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Imaging of stomach

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Imaging of stomach

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Imaging of stomach

  1. 1. EMBRYOLOGY
  2. 2. Sagittal sections through embryos at various stages of development demonstrating the effect of cephalocaudal and lateral folding on the position of the endoderm-lined cavity. Note formation of the foregut, midgut, and hindgut. A. Presomite embryo. B. Embryo with seven somites. C. Embryo with 14 somites. D. At the end of the first month
  3. 3. • The stomach appears as a fusiform dilation of the foregut in the fourth week of development. • During the following weeks, its appearance and position change greatly as a result of the different rates of growth in various regions of its wall and the changes in position of surrounding organs. Positional changes of the stomach are most easily explained by assuming that it rotates around a longitudinal and an anteroposterior axis
  4. 4. Embryos during the fourth (A) and fifth (B) weeks of development showing formation of the gastrointestinal tract and the various derivatives originating from the endodermal germ layer
  5. 5. • The stomach rotates 90° clockwise around its longitudinal axis, causing its left side to face anteriorly and its right side to face posteriorly. Hence, the left vagus nerve, initially innervating the left side of the stomach, now innervates the anterior wall; similarly, the right nerve innervates the posterior wall. • During this rotation, the original posterior wall of the stomach grows faster than the anterior portion, forming the greater and lesser curvatures
  6. 6. • The cephalic and caudal ends of the stomach originally lie in the midline, but during further growth, the stomach rotates around an anteroposterior axis, such that the caudal or pyloric part moves to the right and upward, and the cephalic or cardiac portion moves to the left and slightly downward. The stomach thus assumes its final position, its axis running from above left to below right.
  7. 7. Rotation of the stomach along its longitudinal axis as seen anteriorly. D,E. Rotation of the stomach around the anteroposterior axis. Note the change in position of the pylorus and cardia.
  8. 8. Transverse section through a 4-week embryo showing intercellular clefts appearing in the dorsal mesogastrium. B,C. The clefts have fused, and the omental bursa is formed as an extension of the right side of the intraembryonic cavity behind the stomach.
  9. 9. Primitive dorsal and ventral mesenteries. The liver is connected to the ventral abdominal wall and to the stomach by the falciform ligament and lesser omentum, respectively. The superior mesenteric artery runs through the mesentery proper and continues toward the yolk sac as the vitelline artery.
  10. 10. ANATOMY
  11. 11. RADIOLOGICAL TECHNIQUE
  12. 12. Conventional Radiography • The widespread use of cross-sectional imaging has significantly diminished the role of conventional radiographic techniques (plain radiography and contrast X-ray examinations) in the diagnosis of diseases of the stomach and duodenum.
  13. 13. Plain Abdominal Radiograph • Currently, the plain abdominal radiograph remains a first-line investigation in the acute setting; although there is a clear move towards cross-sectional techniques such as US and CT as part of the initial patient assessment. • In the non-acute situation, plain abdominal radiography offers little information and is now almost obsolete.
  14. 14. CAUSES OF A MASSIVELY DILATED STOMACH • Mechanical gastric outlet obstruction • Duodenal or pyloric canal ulceration • Carcinoma of pyloric antrum • Extrinsic compression • Paralytic ileus • Surgery • Trauma • Peritonitis • Pancreatitis • Cholecystitis • Diabetes • Hepatic coma • Drugs • Gastric volvulus • Intubation • Air swallowing
  15. 15. Gastric Dilatation • Mechanical gastric obstruction caused by peptic ulceration or carcinoma often leads to a huge fluid-filled stomach that occupies most of the abdomen and is demonstrated as a soft-tissue mass with little or no bowel gas beyond.
  16. 16. • Usually a little gas is present in the stomach, which allows the organ to be identified. • When supine, a gas-filled stomach can usually be identified with the wall of the greater curvature convex caudally and the pyloric antrum pointing cranially. It is important to differentiate a distended stomach from a caecal volvulus, which may also be positioned beneath an elevated left hemidiaphragm. Acute gastric dilatation after trauma
  17. 17. Complication of endoscopy. A linear collection of intramural gas surrounds the stomach
  18. 18. X-ray contrast studies • Although largely replaced by endoscopy, X-ray contrast studies remain the basic radiological technique for investigation of diseases of the oesophagus, stomach, and duodenum. • Barium meal is used for examination of the lower oesophagus, stomach, and duodenum
  19. 19. • high-density barium suspension • The best results are achieved using either high-density barium (200% wt/vol – i.e. E-Z-HD) or intermediate density (100% wt/vol) barium such as Baritop
  20. 20. • There are four basic techniques to the performance of this examination: – compression, – mucosal relief – barium filling and – double-contrast
  21. 21. SINGLE-CONTRAST EXAMINATION • A properly performed single-contrast examination will emphasize : – mucosal relief, – compression and – barium filling.
  22. 22. Mucosal relief radiographs • Obtained at the onset of the examination in both the prone and supine positions with approximately 60–90 ml of barium. • The objective being demonstration of the gastric fold pattern. • The anterior gastric wall is evaluated on the prone images, an area that may not be well demonstrated on a routine double-contrast examination.
  23. 23. Compression filming • The stomach is moderately distended with barium suspension. The amount of barium administered should be sufficient to spread the rugal folds in the antrum. • Only those portions of the stomach distal to the inferior rib cage are accessible to compression. • Images may be obtained with the patient prone, supine and/or upright on the radiographic table. • It should be appreciated that compression filming demonstrates both the anterior and posterior walls of the distal stomach. • Many ulcers and masses can be demonstrated in the compressible areas of the stomach.
  24. 24. • Compression of distal antrum with patient upright. Rugal folds are well seen. The descending duodenum overlies in antrum. Note: Pylorus (P).
  25. 25. DOUBLE-CONTRAST TECHNIQUE • An anti-peristaltic agent such as glucagon or buscopan is often employed to delay filling of the small bowel during the study. • Glucagon produces gastric hypotonia within 45 s of the injection. It also tends to delay gastric emptying, allowing better views of the antrum and the body of the stomach. – Contraindications: pheochromocytoma and insulinoma. • Buscopan produces transient hypotonia of stomach and duodenum. In addition, it causes pyloric relaxation, allowing excellent double-contrast views of the duodenum. – Contraindications: glaucoma, potential cardiovascular side effects
  26. 26. • The double-contrast technique involves the ingestion of an effervescent, gas-producing agent composed of sodium bicarbonate and an antifoaming agent. • When swallowed with a small amount of water, the granules or tablets release 300–500 ml of carbon dioxide, which distends the stomach. • The gastric walls are then coated with 100–150 ml of ingested high-density barium suspension. The density of the barium used in these examinations is typically around 250 per cent weight/volume.
  27. 27. • Double-contrast technique provides exquisite detail of the mucosal surface of the stomach. • Lesions on the dependent surface of the stomach (the posterior wall in the supine patient) are best seen using double-contrast technique. • Anterior wall lesions may be more difficult to identify. For that reason, compression and/or mucosal relief filming is frequently employed in conjunction with double-contrast technique. • This, in effect, is a ‘BIPHASIC’ upper gastrointestinal barium examination.
  28. 28. Limited double-contrast examination • Part of the conventional single-contrast examination using air ingested with swallowing or by drinking through a straw. • Given the lower density of the barium utilized, this is not as sensitive as the dedicated double-contrast examination.
  29. 29. EXAMINATION WITH WATER-SOLUBLE CONTRAST MEDIA • Evaluate a suspected perforation. – Barium may lead to granuloma formation and peritoneal fibrosis. • If aspiration is suspected or likely, water-soluble, non-ionic (low osmolar) contrast media should always be used first. – An ionic, water-soluble contrast medium such as Gastrografin must be avoided as it can cause severe pulmonary oedema if aspirated. • The patient must be examined in both prone and supine positions to preclude a leak from the anterior wall.
  30. 30. RADIOGRAPHIC APPEARANCE • Gastric mucosa is characterized by two features: – the areae gastricae, which form the mucosal surface pattern, and – the gastric rugae, which form the gross or macromucosal pattern.
  31. 31. Normal areae gastricae pattern • Fine reticular network produced by barium trapped in criss-crossing grooves (sulci gastricae) dividing the gastric mucosa into 2–4 mm polygonal islands of mucosa.
  32. 32. • 50–75 per cent of high-quality double-contrast barium studies, • most often in the antrum and body. • The pattern is rarely seen on single-contrast studies • not usually visualized endoscopically unless a dye such as methylene blue is applied to the mucosa. • Visualization of the areae gastricae is considered an indicator of adequate coating of the stomach.
  33. 33. Areae gastricae. The normal pattern seen with a well-coated gastric mucosa at barium meal Abnormal areae gastricae. The pattern is disturbed in this patient with a carcinoma of the fundus not noted at endoscopy (also note the gastric diverticulum) • Abnormalities of the areae gastricae may be seen in peptic ulcer disease (PUD), particularly in Helicobacter pylori infection, where they may be enlarged forming a coarser pattern. • Focal distortion or absence of the areae gastricae pattern is often seen with gastric tumours. • In diffuse atrophic gastritis the normal areae gastricae pattern is absent.
  34. 34. Gastric rugae • Smooth folds that tend to parallel the long axis of the stomach • About 3–5 mm thick on barium studies. • These comprise mucosa and a portion of submucosa. • Abnormalities: – Thicker and nodular rugal folds – Infiltrative disease (e.g. scirrhous carcinoma) may efface the rugae. – Disruption of the normal longitudinal orientation of the rugae. – Radiating folds converging to a central point with healing gastric ulcers.
  35. 35. • Three dimensional anatomic relationship – to properly position patients for upper gastrointestinal studies – demonstrating each portion of the stomach and its relationship to adjacent structures. • The fundus lies posteriorly in the left upper quadrant while • the body and antrum course on a relatively horizontal plane to lie anteriorly and cross the midline. • The distal antrum courses posteriorly to the right of the spine with the pylorus directed posteriorly.
  36. 36. • CT of normal stomach distended with positive contrast and air. (A) Normal soft-tissue prominence at gastro-oesophageal junction. Fundus is posterior. The body courses anteriorly. (B) On a slightly more caudad image, the antrum turns in a posterior direction. Normal, thin gastric wall is seen. Note relationships to liver, spleen, colon and diaphragm.
  37. 37. • The greater curvature forms the anterior wall of the stomach and, similarly, the lesser curvature forms the posterior wall. • Variability in the length of the mesenteric attachments leads to a more horizontal orientation of the stomach in muscular and obese people, and a more vertical orientation in slender people and in the geriatric population.
  38. 38. CT - Technique • spiral CT > standard CT • MDCT – improved multiplanar capabilities. • Water as a negative oral contrast agent – good visualization of the underlying enhancing mucosa – improved 3D reconstruction (because there is no intervening positive contrast material in the lumen.)
  39. 39. • The gastric cardia to adequately distend, an effervescent agent can be incorporated. • Positioning of the patient in the left lateral decubitus or left posterior oblique positions can improve distension of the antrum and cardia. • Positioning the patient prone improves fundal distension.
  40. 40. • With fast scanning, virtual gastroscopy has developed and may further improve lesion detection and staging of gastric cancer
  41. 41. Aspects of CT anatomy • A well-distended stomach has a wall thickness of approximately 5 mm. This measurement should be obtained in between the rugal folds. • Layered enhancement of the normal gastric wall – The mucosa brightly enhances, while the submucosa remains lower in attenuation. The muscular-serosal layer has moderate enhancement.
  42. 42. The normal appearance of the gastric wall may only have a single, two- or three-layered appearance • CT scan performed during the arterial phase shows normal single-layer enhancement of the gastric wall (arrow).
  43. 43. The normal appearance of the gastric wall may only have a single, two- or three-layered appearance • CT scan performed during the arterial phase shows normal double- (arrow) and triple-layer (curved arrow) enhancement of the gastric wall. Hyperenhancing mucosa is easily identified with water used as a negative oral contrast agent. • B: Portal venous phase image through the same region demonstrates a more homogeneous mural enhancement without stratification
  44. 44. Virtual Gastroscopy • This technique can likewise be applied to the stomach for virtual evaluation. Following air distension of the stomach we can apply the ‘fly-through technique’ to the stomach to visualize the gastric folds, pylorus etc. Normal appearance of gastric folds as seen on the virtual endoscopy. Image shows a view from the fundus looking into the body of the stomach. (B) Normal appearance of the pylorus as seen on the virtual endoscopy
  45. 45. MRI - Technique • Patient preperation – Fasting for 4 – 6 hours – 500 – 1000mL contrast for optimal distension – Antiperistaltic agent – buscopan – Positioning – tumor location – GE jn – ECG gating
  46. 46. Conventional MRI • Combination of T1-weighted spoiled gradient echo with and without contrast enhancement and • T2-weighted single shot turbo spin-echo sequences using breathhold techniques to avoid misregistration errors. • The field of view (FOV) used is 400 × 400 mm • Matrix size of 192 × 256 mm • Slice thickness between 8 and 10 mm • voxel size of between 25.96 and 32.45 mm. • Axial planes together with sequences perpendicular to the plane of the tumor to asses for resectability
  47. 47. High-Resolution MRI • External Surface Coil – For tumors at the gastro-esophageal junction • single-shot coronal T2-weighted sequence also acquired – cranio-caudal extent of the tumor – extension of disease above and below the diaphragmatic hiatus • Diffusion-weighted imaging – locally advanced (T3/T4) tumors, showing resticted diffusion (Sakurada et al. 2009). – hoped to differentiate benign from malignant lymph nodes.
  48. 48. • Endoluminal: Endoscopic coils – optimum coil positioning close to the site of the tumor and – clearly overcomes the difficulty of motion artifact (Kulling et al. 1997).
  49. 49. An endoscope used for endoscopic MR imaging is not very different from other gastroscopes, but it is manufactured with materials that do not produce artefacts which interfere with imaging. a The endoscope used by Dux et al (2001). The tip of the endoscope b shows the oversized biopsy channel that is used to advance the coil into the stomach. c The prototype of the receiver coil used nowadays. The diameter of the coil released from the endoscope is variable depending on the size of the tumour that is to be imaged. d shows that the endoscope is compatible with MRI, and the channel that accommodates the receiver coil is clearly depicted
  50. 50. • Endoluminal: Endoscopic and Expandable surface Coils – self-expanding loop coil. – enables high-resolution imaging of the primary tumor • location adjacent to the tumor and • Larger diameter of the coil (8 cm) than the endoscopic MR increasing the radius for receiving signal from 3–4 cm to 8 cm. – detailed analysis of the depth of tumor invasion through the layers of the stomach wall and – assessment of involvement of the gastric serosa and surrounding tissues (Heye et al. 2006).
  51. 51. Endoscopic MR imaging of the stomach. • The receiver coil (arrowheads) was advanced into the lumen of the stomach and covers an area of 9–10 cm that can be used for imaging. • A small early gastric carcinoma (arrow) is located within the gastric wall and has infiltrated the submucosa. The submucosa is represented by the middle, hypointense layer of the gastric wall (∗)
  52. 52. Normal Anatomy on MRI – Wall Layers • Endoluminal coil demonstrates the main component layers of the stomach wall: – The mucosa (low signal intensity), – submucosa (low or high signal intensity, dependent on the sequence parameters), and – muscularis propria (low signal intensity) on both T1- and T2-weighted sequences (Inui et al. 1995).
  53. 53. Sometimes two layers may be distinguished using T2-weighted sequences (arrow, a). In addition a polypoid tumour (arrowhead) of the gastric wall is visible. The patient was positioned prone, and water was used for luminal distension. In contrast, experimental high-spatial-resolution MR imaging of the stomach reveals three layers of the gastric wall b. Opposed-phase imaging shows an early gastric carcinoma (∗), type I, that does not penetrate the second/middle gastric wall layer. (1) mucosa, (2) submucosa, (3) muscularis propria
  54. 54. • The muscularis propria layer as three distinct layers: – the inner circular muscle (low signal intensity), – interposed connective tissue (high signal)and – the outer longitudinal muscle layer (low signal intensity) (Yamada et al. 2001; Heye et al. 2006)
  55. 55. Normal Anatomy on MRI – Surrounding Structures • superior soft tissue contrast – particularly when structures lie in direct contact with no interposing fat plane. • multi-planar capability – assessment of the relationship of the stomach to the pancreas, left lobe of the liver, and transverse colon.
  56. 56. Clinical Application: Staging of Malignant Disease • T Staging – Assessment of resectability • N staging • Metastatic disease – Characterisation of focal liver lesions – Identify peritoneal infiltration
  57. 57. T Staging Experimental high-spatial-resolution MRI of gastric specimens Opposed-phase imaging is best suited to diagnose gastric tumours because of their high signal intensities. The images show a carcinoma (∗) of the gastric antrum that involves the whole circumference of the gastric wall. At histology and MRI, mesenteric infiltration (arrow) was diagnosed and the tumour finally was staged pT4.
  58. 58. T Staging • An axial view of a gastric specimen at T2-weighted imaging. • The carcinoma (∗) penetrates the gastric wall and infiltrates liver tissue that therefore was resected. • Local invasion of the liver was correctly depicted by MRI that showed tiny areas of signal intensity changes (arrow) within the liver parenchyma. • Compared to that of the primary tumour the areas of focal invasion have similar signal intensities
  59. 59. N Staging • A signet ring cell carcinoma (∗) involving more than two-thirds of the gastric wall as well as locoregional lymph node metastases (arrows) that have signal intensities identical to that of the primary tumour.
  60. 60. Clinical Application : Evaluation of Gastric Motility • assessment of gastric emptying • Increased or decreased gastric motion can be reliably distinguished with MRI; this imaging modality may be an attractive alternative to conventional invasive diagnostic tools for diagnosis of gastric motility disorders and consecutive therapeutic monitoring (Ajaj et al. 2004).
  61. 61. Endoscopic Ultrasound of the Stomach • two basic types of echoendoscope – radial or linear array transducer technology. – The bowel is a tube- radial scanning is the most appropriate. • Doppler facilities • Miniprobes • The use of contrast-enhanced EUS has been discussed and may in selected cases add further additional information (Nomura et al. 1999). Close-up of the tip of the Olympus GF-UM200 echoendoscope demonstrating the partially inflated water-filled balloon
  62. 62. Bowel Wall Anatomy • The normal stomach wall at 12 Mz. The five layers, between arrows, are well demonstrated. b= water-fi lled balloon and associated ring-artefacts. • Close-up of image 1. an echogenic layer representing the interface between the balloon (b) and the superficial mucosa, 2. a hypoechoic layer representing the deeper mucosa including the muscularis propria, 3. an echogenic layer comprising the submucosa, 4. a hypoechoic layer, the muscularis propria, and 5. the echogenic serosa
  63. 63. Bowel Wall Anatomy • Higher-frequency probes are able to identify up to nine distinct layers including the circular and longitudinal muscle components of the muscularis propria.
  64. 64. • The coeliac trunk with its common hepatic and splenic artery branches are useful landmarks with significant importance for tumour staging. Coeliac trunk and its major divisions likened to a “whale’s tail”. Ao= aorta, CT= coeliac trunk, SpA= splenic artery, HA= hepatic artery
  65. 65. Applications - Benign Pathology • Submucosal Lesions – Gastrointestinal stromal tumours (GISTs) have a characteristic appearance and usually arise from the fourth hypoechoic layer corresponding to the muscularis propria, A stromal tumour (*) clearly arising from the muscularis propria (arrows) of the stomach wall. Imaging features suggest an entirely benign lesion
  66. 66. • a lipoma is seen as a well-defined mass, more echogenic than a GIST, usually confined to the submucosal layer displacing adjacent muscle layers A lipoma (*) arising from the submucosal layer (sm) of the stomach wall. The muscularis propria (mp) is displaced but not directly involved
  67. 67. • An intramural gastric lesion (*) with indeterminate EUS imaging features. The precise layer of origin deep to the muscularis mucosa (arrow) is unclear. Diagnostic uncertainty and noncontributory biopsies necessitated surgical resection. Aberrant pancreas proven histologically
  68. 68. • Thickened Folds – which wall layers are causing the thickening and – whether or not the layered structure is preserved. • Thickening of the mucosa is seen in various types of gastritis, Ménétrier’s disease, and some patients with early lymphoma. • More generalized thickening with loss of the layer structure suggests malignancy, such as advanced lymphoma or linitis plastica. Enlarged submucosal gastric vessels (arrows). Identification of intramural and adjacent vessels clearly important if trans-gastric biopsy or drainage is being considered
  69. 69. Applications - Malignant Pathology • Gastric Cancer – T Staging
  70. 70. • Gastric tumour (T). • There is definite localised breach of the muscularis propria (white arrow), suggesting T3. • Muscularis propria (mp) elsewhere intact
  71. 71. Applications - Malignant Pathology • Gastric Cancer – Nodes • Lymph nodes are well seen, and certain features correlate well with malignant infiltration: – Nodes greater than 1 cm diameter, with – well-defined margins, – rounded and – hypoechoic are likely to be involved (Catalano et al. 1991). A perigastric lymph node (n) measuring 14 mm in diameter with imaging features suggesting metastatic involvement
  72. 72. • The presence of direct invasion into adjacent structures (T4) can be difficult to establish on both CT and EUS. • Using CT, the suggestion of invasion is often based solely upon the area of contact with the contiguous organ, but EUS also allows evaluation in real-time, and free movement between the tumour and the adjacent organ (particularly the liver) excludes direct invasion Sizeable T2 gastric tumour. Arrow demonstrates clear line of separation from the adjacent liver (L). Realtime scanning demonstrated obvious movement between the tumour and the liver, making invasion unlikely
  73. 73. • Small-volume ascites, frequently undetected by other imaging modalities, can also be demonstrated with EUS, and will alert the surgeon to the possibility of peritoneal spread. Ascites (*) between the free edge of the left lobe of liver (LL) and the left hemi- iaphragm (arrow)
  74. 74. Gastric Maltoma • EUS has been shown to be more sensitive than endoscopy or CT for accurate staging and crucial for predicting tumour response to bacterial eradication (Ruskoné- Formestraux et al. 2001). Patient with biopsy-proven maltoma following a course of H. pylori eradication. Post-treatment biopsies suggested disease-free, but EUS demonstrates persistent abnormality (m). Further targeted biopsies confirmed persistent disease
  75. 75. Interventional EUS • accurate guidance for – injection, – biopsy, – aspiration, and – drainage
  76. 76. Radionuclide Imaging of the Stomach • simple, noninvasive means of quantifying gastric motor function and is presently considered the “gold standard” for this purpose.
  77. 77. Radiopharmaceutical Meals • Solid, liquid, or semisolid meals – solid (99mTc-tin colloid in scrambled egg) – liquid (111In-DTPA in water) • The radiopharmaceuticals used for gastric emptying must be nonabsorbable, as this will reduce the radiation dose outside the GI tract
  78. 78. Indications • symptoms of gastroparesis and diffuse gastrointestinal dysmotility • the follow-up of patients who have undergone various surgical procedures for peptic ulcer and other GI abnormalities • Gastric emptying studies are also useful in quantifying the effect of medical and therapeutic interventions. • pivotal role in drug development in recent years
  79. 79. Patient Preparation • fast overnight. • drugs known to influence gastrointestinal motility should be discontinued for 24 hours. • refrain from smoking and consuming caffeine containing drinks on the morning of the test.
  80. 80. • Dual-isotope gastric emptying study using solid (99mTc-scrambled egg) and liquid (111In- DTPA in water) meals. • Images were acquired immediately, 20, 40, 60, and 120 minutes after meal ingestion
  81. 81. • Liquid Gastric Emptying – Exponential • Solid Gastric Emptying – early lag phase before the food enters the duodenum (Sheiner et al. 1980), followed by a linear pattern Gastric emptying curves for solids and liquids in normal subjects
  82. 82. Disorders of Gastric Emptying
  83. 83. PET • Positron emission tomography (PET) has proven itself to be valuable in the evaluation of patients with gastric cancer. • The study utilizes [F-18] Fluoro-2-deoxy-glucose as a marker of tumor activity. • It is a functional technique that images tissue metabolic activity. • Fusion of PET with CT is rapidly becoming the standard of care when diagnosing malignancy. • PET/CT is currently used for staging and restaging of gastric lymphoma as well as following response to therapy.
  84. 84. FDG PET/CT. The images depicted show first normal uptake of FDG by the stomach and second increased uptake in an area of proven gastric lymphoma
  85. 85. PATHOLOGY
  86. 86. Classification • Congenital • Inflammatory • Infectious • Positional • Vascular • Trauma • Foreign body • Miscellaneous • Post surgical • Neoplastic
  87. 87. Classification • Congenital • Inflammatory • Infectious • Positional • Vascular • Trauma • Foreign body • Miscelleous • Post surgical • Neoplastic
  88. 88. Congenital • Gastric duplication cyst • Gastric diverticulum • Ectopic pancreas • Situs anomalies
  89. 89. Gastric Duplication cyst • Gastric duplication cyst is the least common of the enteric duplications. • 7% of GI tract duplications. • Usually asymptomatic, but occasionally present with vomiting and abdominal pain. • Most commonly seen in infants.
  90. 90. Gastric Duplication cyst • Gastric duplication cyst in a 21-year-old female presenting with epigastric pain. • CT reveals a hyperdense cystic lesion along the medial wall of the fundus with an air speck within it suggesting focal communication with the stomach. • Pathology confirmed gastric mucosa within the cystic lesion. The age of presentation, location and communication with the stomach are all unusual for a gastric duplication.
  91. 91. Congenital Gastric Diverticula • Gastric diverticula are uncommon and usually asymptomatic (Compared to duodenal diverticulae). • Posterior wall of the gastric cardia are the most common site. • Often single, varying in size from 1 - 3 cm. • Occasionally can be multiple and large.
  92. 92. • These are true diverticula, i.e. containing muscularis propria, and thus are capable of peristalsis. • They are usually several centimetres in size and readily fill with barium. • They rarely present a diagnostic dilemma but may mimic a submucosal mass if they fail to fill with barium. • They may be mistaken for a gastric ulcer. Large fundal diverticulum. The patient is upright and a barium/air level is present in the diverticulum.
  93. 93. • Gastric cardia diverticula may simulate a left adrenal mass. • Air-fluid level, retained contrast, communication with stomach and wall enhancement help in differentiating it from other masses.
  94. 94. Ectopic pancreas • pancreatic rest, aberrant pancreas • presence of pancreatic tissue in the submucosa of the luminal gastrointestinal tract. • MC along the greater curvature of the antrum. • The ectopic pancreatic tissues are usually solitary deposits that appear as sharply defined submucosal nodules usually <2 cm. A central depression that collects barium, thought to represent a rudimentary duct, is present in about 50 per cent of cases. • When this is present, the appearance is pathognomonic. • If there is no central depression, the appearance is indistinguishable from other small submucosal lesions. • If the central barium collection is prominent, ulceration is a diagnostic consideration.
  95. 95. Ectopic Pancreas in the stomach. Double Contrast barium study (a) shows a small nodule in the antrum of the stomach (bottom left of image). Endoscopy (b) demonstrates the characteristic round umbilicated lesion situated a few centimeters proximal to the pylorus. Biopsy confirmed ectopic pancreas (pancreatic rest)
  96. 96. Pancreatic rest. • The typical position in the gastric antrum and the small pit due to the rudimentary duct gave the clue to the diagnosis
  97. 97. Classification • Congenital • Inflammatory • Infectious • Positional • Vascular • Trauma • Foreign body • Miscellaneous • Post surgical • Neoplastic
  98. 98. Helicobacter pylori and diseases of the stomach • H. pylori is a Gram-negative, flagellated, spiral bacterium recognized as the most important cause of: – PUD, – chronic gastritis, – gastric ulcer, – duodenitis, – duodenal ulcer and – Adenocarcinoma – MALT lymphoma
  99. 99. PREVALENCE OF HELICOBACTER PYLORI INFECTION WITH UPPER GI DISEASE Disease Prevalence(%) Active chronic gastritis 100 Duodenal ulcer 95 Gastric cancer (body or antrum) 80–95 MALT lymphoma 90 Gastric ulcer 60–80 Nonulcer dyspepsia 35–60 Asymptomatic population 20–55
  100. 100. • Acute infection initially injures parietal cells causing decreased gastric acid production. • This is followed by the chronic stage of infestation, which is localized to the distal stomach and duodenum. Parietal cell function recovers, leading to abnormally high acid output. This causes antral gastritis and duodenitis, with approximately 1 per cent of infected patients developing peptic ulcers every year.
  101. 101. Gastric ulcer • penetrate the stomach wall through the mucosa into the submucosa and frequently the muscularis propria • Among the most common gastrointestinal disorder and is amenable to reliable radiographic detection. • 95 % benign – H. pylori (70 %) – NSAIDs – Alcohol abuse • most prevalent in the distal stomach and along the lesser curvature. • more common on the posterior wall of the stomach • NSAID- and alcohol-related ulcers are most often seen on the greater curvature of the antrum (direct toxic effect of the ingested material)
  102. 102. Findings Benign Malignant Extends beyond gastric wall Yes No Folds Smooth, even Irregular, nodular, may fuse Associated mass Absent Present Ulcer shape Round, oval, linear Irregular Healing Heals completely Rarely heals Hampton's line Present Absent Carman meniscus Absent Present
  103. 103. En face appearance of benign gastric ulcer. (A) Posterior wall ulcer is nearly filled with barium in this RPO projection. Thin regular radiating folds (best seen around the inferior border of the ulcer) are seen converging to the ulcer. (B) Unfilled benign ulcer crater is outlined by a ‘ring’ shadow. This ulcer is surrounded by a prominent ring of oedema – the lucent area around the crater.
  104. 104. Profile views of benign gastric ulcer. (A) Hampton's line, a thin line of radiolucency crossing the opening of an ulcer, a virtually infallible sign of a benign ulcer. (B) Lesser curvature ulcer with a clearly visible ulcer collar. (C) Large lesser curvature ulcer niche, its projection from the lumen of the stomach strongly suggesting a benign lesion. (D) Smooth, straight radiating folds converge at the ulcer crater.
  105. 105. Benign lesser curve ulcers: double-contrast barium meal study shows a benign penetrating lesser curve ulcer seen in profile. A benign lesser curve ulcer seen en face
  106. 106. Healing ulcer • As benign ulcers heal they may change shape from round or oval to linear crevices. There may be subtle retraction or stiffening of the affected wall. • An easily recognizable radiographic sign of healed gastric ulcer is the presence of folds converging to the site of the healed ulcer. There may be a residual central pit or depression. The radiating folds should be uniform. Note the linear scars extending right to the ulcer edge and the lack of distortion of the areae gastricae
  107. 107. Healing gastric ulcer. (A) Focal retraction along the incisura angularis with small residual out-pouching is present. Converging smooth folds no longer fill an ulcer crater. (B) Radiating folds converging to a linear scar.
  108. 108. • Incomplete healing, irregularity of the folds, residual mass or loss of mucosal pattern all suggest the possibility of an underlying malignancy
  109. 109. Malignant gastric ulcer. • The term ‘malignant ulcer’ is used to indicate an ulcer within a gastric mass, usually a carcinoma. • Note the clubbing and fusion of some folds
  110. 110. Carman meniscus sign and gastric adenocarcinoma. Image from a single-contrast upper gastrointestinal study shows a large filling defect (arrows) in the antrum with a large central ulcer (*) convex relative to the lumen Kanne J P et al. Radiographics 2006;26:129-142
  111. 111. Kirklin’s meniscus complex • Consists of Carmen’s meniscus sign plus elevated rim of tumor surrounding crater • Ulcer - Barium filled • Halo - Rim of malignant tissue
  112. 112. Malignant Lesser Curve Ulcers Irregular ulcer crater with nodular and amputated radiating mucosal folds indicating infiltration a “Carman meniscus” sign (arrow) is seen, which represents the ulcer crater with an associated elevated border
  113. 113. Gastric Ulcer on CT Benign gastric ulcer on the posterior Wall of the stomach. Note the sharp margins of the ulcer crater (arrows) and evidence of the ulcer burrowing into the gastric wall. A malignant gastric ulcer on the posterior wall of the stomach. Note the somewhat heaped up ulcer crater margins (arrows) and the more intraluminal position of the ulcer.
  114. 114. Lymphoid Follicular Hyperplasia • H. pylori infection is also related to the presence of lymphoid follicular hyperplasia, which is commonly present in patients with peptic ulcer disease (Torigian et al. 2001). Follicular lymphoid hyperplasia: double-contrast barium meal study shows follicular lymphoid hyperplasia involving the antrum
  115. 115. Gastric Erosions or Aphthous Ulcers • Shallow ulcerations that do not penetrate the muscularis mucosa • Usually appear as small, shallow collections of barium 1–2 mm in diameter’ erosions. • Gastric erosions are most often causally related to H. pylori infection. Other causes include alcohol, NSAID ingestion and crohn's disease. They may also be seen as a response to stress, for example in patients with severe trauma.
  116. 116. Erosive gastritis: double-contrast barium meal studies in two different patients demonstrating erosive gastritis involving the antrum (a) and the entire stomach (b)
  117. 117. ‘COMPLETE’ or ‘varioloform’ - surrounded by a radiolucent rim of oedema. ‘INCOMPLETE’- halo of oedema is lacking
  118. 118. Gastritis • Descriptive term with sometimes conflicting pathological, endoscopic and radiographic definitions • H. Pylori has been shown to be the most common cause of gastritis • The most common findings (H. pylori) are: – Thick (>5 mm) folds with or without nodularity. – Erosions – Others - antral narrowing, inflammatory polyps and prominent areae gastricae. • Combination of thick folds and enlarged areae gastricae may be the most specific findings
  119. 119. • Diffuse erosive gastritis with thick nodular folds. Erosions are scattered along the folds
  120. 120. Chronic antral gastritis with several rows of erosions converging towards the pylorus (a), also shown on the double-contrast barium meal (b)
  121. 121. Atrophic gastritis • combination of atrophy of the gastric glands with histological inflammatory changes • Associated with pernicious anaemia and is more common with advancing age • Loss of parietal and chief cells leading to achlorhydria, and atrophy of the mucosa and mucosal glands • Intestinal metaplasia, which may be seen histologically in atrophic gastritis, is considered a premalignant condition.
  122. 122. • Radiographic findings include: – loss of rugal folds and – a tubular, featureless narrowed stomach. – Areae gastricae may be absent
  123. 123. Hypertrophic gastritis • Misnomer - inflammation is not a prominent • Associated with glandular hyperplasia and increased acid secretion . • There is a high prevalence of duodenal and gastric ulcers in these patients. • D/d - Ménétrier's disease and lymphoma
  124. 124. • Characterized radiographically by thickened folds, often greater than 10 mm in width, predominantly in the fundus and body, which are the acid-producing regions of the stomach. • The areae gastricae pattern may be prominent, up to 4– 5 mm in size and more angular and polygonal than the usual round or oval configuration Hypertrophic gastritis in a patient with a recently healed lesser curvature gastric ulcer. This characteristic enlargement and prominence of the areae gastricae can be correlated with an increased incidence of gastric hypersecretion and PUD
  125. 125. Ménétrier's disease • characterized by – hypertrophy of gastric glands, – achlorhydria and – Hypoproteinaemia - protein-losing enteropathy - manifests as increased fluid in the small bowel. • While in the classic description of Ménétrier's disease the antrum is spared, it has been found to be involved in up to 50 per cent of cases causing diffuse involvement of the stomach.
  126. 126. • markedly enlarged, often bizarre gastric folds most prominent in the proximal stomach and along the greater curvature. • massively thickened often lobular folds. • The folds remain pliable, – D/D - carcinoma, where the stomach becomes rigid and aperistaltic. Classic appearance with massively distended folds in the body sparing the antrum.
  127. 127. • CT – uniform thickening of the gastric wall that may be as much as 1–2 cm. • The most important differential diagnosis is lymphoma (Williams et al. 1978). Ménétrier’s disease. Coronal reformation shows large, lobulated folds and preserved gastric mucosa of the fundus in a patient with biopsy-proven Ménétrier’s disease
  128. 128. Eosinophilic gastritis • focal or diffuse infiltration of the gastrointestinal tract by eosinophils. • crampy abdominal pain, diarrhoea, distension and vomiting, often in an atopic or asthmatic patient. • Peripheral eosinophilia. • most often involves the stomach, especially the antrum and the proximal small bowel. • The clinical and imaging features depend on which layers of the GI tract wall are involved. Involvement may be predominantly mucosal, muscular or subserosal. Many cases are panmural and eosinophilic ascites is often seen in such cases.
  129. 129. • Radiographically eosinophilic gastritis is characterized by fold thickening of the stomach and small bowel. • Antral narrowing and rigidity with mucosal nodularity are frequently seen. CT shows diffuse thickening of the gastric wall in a patient proven to have eosinophilic gastroenteritis. No ascites was present. Symptoms resolved with steroid therapy
  130. 130. Corrosive ingestion • Alkaline substances – oesophagus is usually the target. • Acids - are more injurious to the stomach and duodenum. • The consequences of ingesting a corrosive agent follow a distinct course. First, there is necrosis with sloughing of the mucosal and submucosal layers. In severe cases, full-thickness necrosis of the gastric wall may lead to perforation. In less severe cases, the denuded gastric wall develops a granulating surface and the formation of collagen then leads to fibrosis and stricture. The final result is a deformed, contracted and occasionally obstructed stomach. The outcome is often total gastrectomy.
  131. 131. Radiographic Findings • depend on the severity of the chemical insult and the time that has elapsed since injury. • Initially, swelling and irregularity of the gastric mucosa are seen, occasionally with visible blebs. • As the mucosa sloughs, barium flows beneath it and the mucosa may then be seen as a thin radiolucent line paralleling the outline of the stomach. • After a week or two, fibrotic contraction of the stomach becomes evident. • In severe cases, the lumen of the stomach may be no larger than that of the duodenal bulb. Corrosive gastritis following the ingestion of household bleach. The distal stomach has undergone considerable scarring and contraction in a manner similar to syphilitic gastritis or linitis plastica.
  132. 132. Air in the gastric wall • Disruption of the gastric mucosa permits air to enter the gastric wall. • without an underlying infection - gastric emphysema. – Causes include corrosive ingestion, gastric ulcer, gastric outlet obstruction, chronic obstructive pulmonary disease (COPD), ischaemia and trauma. • caused by an acute infection (gas forming organisms) - emphysematous gastritis. – Escherichia coli and Clostridium welchii. • Acute panmural infectious gastritis (nongas-forming organisms) - phlegmonous gastritis. – alpha-haemolytic streptococcus, Staphylococcus aureus E. coli, C. welchii and Streptococcus pneumoniae.
  133. 133. • The radiological findings in both emphysematous gastritis and gastric emphysema include thin, curvilinear lines of radiolucent gas paralleling the gastric wall. Gastric emphysema on abdominal radiograph in a patient after extensive abdominal surgery. Gastric emphysema. Note air in the wall of the stomach together with much gastric residue. The patient was vomiting as a result of the tumour of the distal stomach, causing gastric outlet obstruction CT of patient with infectious, emphysematous gastritis
  134. 134. Granulomatous processes – Crohn’s disease – Tuberculosis, histoplasmosis and syphilis – Sarcoidosis • Ulceration, thick folds and mucosal nodularity are common features, with antral narrowing being a late feature of these diseases.
  135. 135. Crohn's disease • Gastroduodenal involvement occurs in up to 20 per cent of cases • duodenum alone is more common than the stomach alone • Radiographic findings – almost always involve the antrum or antrum and body of the stomach. – early (non stenotic) disease - aphthous ulcers, larger discrete ulcers, thickened and distorted folds and sometimes a nodular (‘cobble-stoned’) mucosa – Stenotic phase – scarring and fibrosis narrowing the gastric antrum and pylorus into a funnel or “rams-horn”shape. – D/D – other granulomatous diseases, scirrhous gastric carcinoma
  136. 136. Crohn’s Disease of the stomach. Double Contrast barium study (a) shows distortion of the normal gastric mucosal pattern with marked nodularity and multiple aphthous lesions. Note the irregular scalloping affecting the greater curve, due to active Crohn’s Disease. Ultrasound (b) and Endoscopic-ultrasound (c) show marked transmural thickening of the gastric wall. The muscularis propria is intact
  137. 137. Crohn’s disease: stenotic phase with narrowing of the gastric antrum and pylorus
  138. 138. Tuberculosis • Primary tuberculosis of stomach and duodenum is very rare and usually develops secondary to pulmonary tuberculosis. • Simultaneous involvement of the duodenum occurs in 10% of patients. • There is increased incidence in patients with AIDS. • The radiological appearances are classified as predominantly ulcerative or hypertrophic type (Tishler 1979; Agrawal et al. 1999). • The ulcerative form is more frequent and consists of multiple large and deep ulcerations, sometimes with antral fistulas. • In the hypertrophic form, there is thickening of stomach and duodenal folds which can lead to pyloric stenosis and gastric outlet obstruction. A narrowed antrum can mimic a linitis plastica appearance. • There is usually extensive lymph node involvement in the adjacent areas (Tishler 1979; Agrawal et al. 1999).
  139. 139. Gastroduodenal tuberculosis: • Double-contrast barium meal showing destruction of the pre-pyloric region, pylorus, and first part of the duodenum due to intramural ulcers and fibrosis
  140. 140. Other granulomatous diseases • Sarcoidosis and syphilis have identical appearances on conventional barium studies, both ulcerative and hypertrophic Gastric sarcoidosis: Double-contrast barium meal shows nodular thickening of the gastric rugae in a patient with sarcoidosis
  141. 141. Classification • Congenital • Inflammatory • Infectious • Positional • Vascular • Trauma • Foreign body • Miscellaneous • Post surgical • Neoplastic
  142. 142. Infectious gastritis • H. pylori gastritis – the most common infection. • Monilia – the presence of severe oesophageal disease. – Prominent aphthous ulceration
  143. 143. • In immunocompromised patients, – Cytomegalovirus • Deep ulceration, and even fistulization to adjacent structures may be seen with. – Cryptosporidium • primarily affects the small bowel causing severe diarrhoea and thick, small bowel folds. It rarely involves the stomach but has been shown to cause deep ulcers, antral narrowing and rigidity. – Strongyloides • affects the upper gastrointestinal tract, duodenum and proximal small bowel with thickened, effaced folds and narrowing. In advanced cases, the stomach may be narrowed and have thickened folds.
  144. 144. Gastric abscess • Rare condition representing a localized form of suppurative gastritis. • Predispositions: – alcoholism, immunosuppression, diabetes, HIV, old age, foreign body. • CT findings: – Localized mural thickening within stomach wall or focal mass with heterogeneous enhancement. – Fluid and air may be seen within the mass. Adjacent inflammatory stranding may be present.
  145. 145. Gastric abscess • 65-year-old AIDS patient with intramural gastric and liver abscess. • CT reveals heterogeneously enhancing masses in the wall of the stomach and liver . • Biopsy revealed abscess in both the liver and stomach with gram negative organisms.
  146. 146. • Perforated peptic ulcer with multiple gastric and perigastric abscesses. • CT reveals multiple peripherally enhancing abscesses in the gastric and perigastric location along the greater curvature of the stomach.
  147. 147. Classification • Congenital • Inflammatory • Infectious • Positional • Vascular • Trauma • Foreign body • Miscellaneous • Post surgical • Neoplastic
  148. 148. Positional abnormalities • Several peritoneal reflections, permitting it relative mobility • These include the gastrohepatic ligament (lesser omentum), the gastrosplenic ligament and the gastrocolic ligament, which is part of the greater omentum. • The oesophagogastric junction passing through the oesophageal hiatus of the diaphragm normally fixes the proximal stomach while the distal stomach is anchored at the pyloroduodenal junction.
  149. 149. Hiatus hernia • most common positional abnormality • the stomach herniates into the chest through the oesophageal hiatus when there is widening of the opening between the diaphragmatic crura. • The prevalence of hiatal hernia increases with age and is present in over 50 per cent of the aged population. • Most hiatal hernias are small, involving a protrusion of a part of the gastric fundus at least 1.5–2 cm above the diaphragm. At the opposite extreme the entire stomach may be intrathoracic.
  150. 150. Sliding hiatal hernias • most common type of hiatal hernia. • the gastro-oesophageal junction slides proximally through the diaphragmatic hiatus to assume an intrathoracic location. • Small or moderate-sized hiatal hernias are often reducible, changing in size and configuration during barium evaluation. • They are best demonstrated with the patient recumbent in the right anterior oblique position. • Sliding hiatal hernias are often accompanied by gastro-oesophageal reflux and reflux oesophagitis
  151. 151. (A) Sliding hiatal hernia. Chest X-ray shows a large air collection overlying the heart shadow. (B) CT shows a large part of the barium-filled stomach is in the chest. (C) In this patient, an upper GI exam shows that the gastric fundus and most of the body of the stomach is intrathoracic
  152. 152. Paraoesophageal hernias • the gastro-oesophageal junction is in its normal position below the diaphragm. • The proximal stomach herniates through the oesophageal hiatus usually to the left of the distal oesophagus in the posterior mediastinum. • more prone to incarceration and obstruction than a sliding hernia.
  153. 153. Traumatic diaphragmatic hernias • result from a tear in the diaphragm either from a direct penetrating injury or from a sudden increase in intra-abdominal pressure during blunt trauma. • almost always on the left side. • Herniation may occur immediately after trauma or may be delayed by many years. • Diagnosis is often difficult both due to lack of specificity of symptoms and because it is often confused with simple elevation of the hemidiaphragm. • On barium studies the recognition of the gastric hernia lateral to the normal oesophageal hiatus is crucial. • CT is also often helpful in diagnosis.
  154. 154. Gastric volvulus • Occurs when the stomach twists on itself between the points of its normal anatomical fixation. • It may cause gastric outlet obstruction or vascular compromise resulting in a surgical emergency. • Most common in the elderly but may occur at any age. • When acute and obstructing – Abdominal pain – Attempts to vomit without results – Inability to pass an NG tube • Together, these three findings comprise the Borchardt triad which is diagnostic of acute volvulus (in 70% of cases)
  155. 155. Gastric volvulus is often divided into two types depending on the plane of torsion.
  156. 156. Mesentero-axial volvulus The antrum of the stomach has herniated into the chest alongside the oesophagus. Endoscopy was described as difficult and could not be completed, but the cause of the problems encountered was not understood
  157. 157. Radiographic signs • upright plain radiograph: – a double air–fluid level of the stomach in the mediastinum and upper abdomen • barium studies: – the stomach may be inverted with the greater curvature above the lesser curvature, or the pylorus above the cardia and the torsed area identified as the source of the obstruction
  158. 158. EXTRINSIC IMPRESSIONS • Organomegaly or masses in upper abdominal organs may displace or cause extrinsic impressions on the stomach. • These most commonly involve the spleen, left lobe of the liver and pancreas. • These processes may be deduced from the position and configuration of the compression on upper gastrointestinal examination, but are primarily evaluated by computed tomography (CT) or ultrasound (US).
  159. 159. Classification • Congenital • Inflammatory • Infectious • Positional • Vascular • Trauma • Foreign body • Miscelleous • Post surgical • Neoplastic
  160. 160. Infarction • Etiologies: – arterial thrombosis, herniation /volvulus, caustic ingestion, therapeutic embolizations, post-op. • CT features: – Wall thickening with non-enhancing wall. – Intramural gas and perforation may be present. – Associated findings may include other visceral infarctions and portal venous gas. Acute gastric and small bowel infarction in a 62-year -old woman with heart failure and atrial fibrillation. CT reveals thickened non-enhancing gastric wall with pneumatosis . The small bowel is fluid distended and dilated with non-enhancing walls with extensive pneumatosis
  161. 161. Herniation with iscemia Perforation and ischemia of the stomach contained in an epigastric hernia. The distal stomach is seen within the hernia sac and is focally dilated. There is free fluid and air within the peritoneal cavity. Caudal sections reveal gastric perforation.
  162. 162. Varices • patients with portal hypertension and oesophageal varices. • Gastric veins provide one of the collateral pathways when there is obstruction of the portal vein. • The presence of gastric varices in the absence of oesophageal varices is a sign of splenic vein thrombosis most often associated with pancreatitis or pancreatic carcinoma. • often seen in the fundus around the oesophagogastric junction sometimes involving the proximal body. • They appear as widened, effaceable polypoid folds. They may be nodular-appearing, ‘grape-like’ or appear mass-like, in which case they may mimic gastric cancer. Rarely they occur in the antrum without fundal involvement. • Transabdominal and endoscopic US are important techniques for definitive diagnosis of gastric varices. • D/D: for thick polypoid gastric folds includes hypertrophic gastritis, Ménétrier's disease and lymphoma.
  163. 163. • Multiple nodular and curved submucosal masses in the fundus are a common appearance of gastric varices.
  164. 164. Gastric varices. The precontrast images (a, b) demonstrate masses indenting the fundus of the stomach which on (a) in particular could be confused with a fundal tumour. The nature of the abnormality becomes clear following contrast administration (c)
  165. 165. Classification • Congenital • Inflammatory • Infectious • Positional • Vascular • Trauma / Iatrogenic • Foreign body • Miscelleous • Post surgical • Neoplastic
  166. 166. Classification • Congenital • Inflammatory • Infectious • Positional • Vascular • Trauma • Foreign body • Miscelleous • Post surgical • Neoplastic
  167. 167. Bezoars • A bezoar is a mass of foreign matter composed of retained ingested material in the stomach and small bowel. • They can be classified into two main types: phytobezoars and trichobezoars
  168. 168. Trichobezoars • It consist of large quantity of ingested hair firmly matted together, forming an intraluminal cast in the stomach and frequently extending into the duodenum (Choi and Kang 1988). • These are found most commonly in young psychiatric patients, almost exclusively females. • Radiological features of bezoars on contrast studies are very distinctive, allowing a more confident diagnosis with no need for further imaging. • It appears as a large, filling defect with poor barium coating due to uneven filling of the interstices. • There is no constant site of attachment with the stomach wall (Szemes and Amberg 1968; Choi and Kang 1988).
  169. 169. Trichobezoar: double-contrast barium meal showing a large filling defect occupying the whole lumen of the stomach and photograph of the removed trichobezoar
  170. 170. Phytobezoars • caused by: – ingestion of poorly digested fibres, most commonly orange, persimmon skin, and seeds. • Predisposing conditions include: – previous gastric surgery such as Billroth I and II operations, especially if complemented by a vagotomy procedure (Szemes and Amberg 1968). These may lead to decreased motility and digestive ability of the remaining portion of the stomach, thus impairing gastric emptying. Phytobezoar: double-contrast barium meal shows a phytobezoar in a patient with previous partial gastrectomy
  171. 171. Classification • Congenital • Inflammatory • Infectious • Positional • Vascular • Trauma • Foreign body • Miscellaneous • Post surgical • Neoplastic
  172. 172. Hypertrophic Pyloric Stenosis • congenital disorder diagnosed in infancy. • Presentation in adults occasionally occurs. • hypertrophy and hyperplasia of the circular muscle with some contribution by the longitudinal muscle. The hypertrophied muscle lengthens and narrows the pyloric channel. • Radiographically, there is lengthening of the pyloric channel (2–4 cm long) with smooth symmetrical narrowing. The hypertrophied muscle bulges retrograde into the antrum, creating a ‘shoulder’. • In infants US generally provides the definitive diagnosis.
  173. 173. Classification • Congenital • Inflammatory • Infectious • Positional • Vascular • Trauma • Foreign body • Miscellaneous • Post surgical stomach • Neoplastic
  174. 174. SURGICAL APPEARANCES • In the past partial gastrectomy was often performed for PUD. • This consists of antrectomy, vagotomy and creation of either a gastroduodenostomy (Billroth I) or a gastrojejunostomy (Billroth II). • More recently gastric bypass surgery has replaced the Billroth II for weight reduction. • On CT the gastric pouch and the gastric remnant are easily visualized as well as the type of gastric bypass, whether it is a retrocolic, retrogastric or antecolic, antegastric bypass. • Complications such as obstruction or extravasation are also seen readily on CT. • The most common method of following up a bypass patient is a single-contrast upper GI study, usually 1–2 days postoperatively.
  175. 175. The stomach is foreshortened due to an antrectomy with a gastroduodenostomy. This is a Billroth I - type anastomosis Vagotomy, partial gastrectomy, and Billroth-ll anastomosis. Note the metallic clip at the esophagogastric junction.
  176. 176. • Pyloroplasty – widen the lumen of the pylorus and facilitate gastric emptying. – frequently combined with a vagotomy. – the normal pyloric contours are lost, and a pouch-like deformity may be observed. • Fundoplication procedures – To prevent gastro-oesophageal reflux and produce a characteristic deformity of the gastric cardia.
  177. 177. COMPLICATIONS OF GASTRIC SURGERY • Submucosal haemorrhage – may lead to outlet obstruction – usually self-limited and subsides within 10 days. • Leakage from the duodenal stump or anastomosis after gastrojejunostomy – most common cause of death during the postoperative period. – The incidence of this complication is 1–5 per cent, with a mortality rate of 40– 50 per cent. – Stump leakage usually occurs during the first 2 weeks after surgery. • Ischaemia of the stomach leading to necrosis and fistula formation – significant morality rate. • Leakage - diagnosed after ingestion of water-soluble contrast material. • Persistent severe diarrhoea caused by inadvertent gastroileostomy instead of gastrojejunostomy also is best diagnosed by upper gastrointestinal examination
  178. 178. COMPLICATIONS OF GASTRIC SURGERY • Marginal ulcerations – 3–10 per cent of patients who have been operated on for PUD. – within the first 2 cm of anastomosis on the jejunal side – usually caused by inadequate vagotomy.
  179. 179. COMPLICATIONS OF GASTRIC SURGERY • Afferent loop obstruction – may be acute or chronic. – This is usually caused by herniation of the afferent loop through a surgically created defect behind the gastroenteric anastomosis. – Chronic afferent loop obstruction occurs because of preferential gastric emptying into the afferent loop . – Patients present with intermittent bilious vomiting, weight loss, malabsorptions and steatorrhoea. – Preferential filling of the afferent loop is seen on upper gastrointestinal examination. – Barium is retained within the afferent loop on delayed films, and regurgitation of contrast material into the stomach from the afferent loop may be recognized. – This syndrome may be associated with a very long afferent loop.
  180. 180. COMPLICATIONS OF GASTRIC SURGERY • Efferent loop obstruction – usually caused by spasm and inflammation. – manifested between the fifth and tenth postoperative days, – usually a self-limited phenomenon not requiring specific treatment. – Upper gastrointestinal examination reveals delayed transit in the efferent loop
  181. 181. COMPLICATIONS OF GASTRIC SURGERY • Prolapse and intussusception may occur at the anastomosis postoperatively. – Jejunogastric intussusception is the most common abnormality of this type. – Either the afferent or the efferent loop may be involved, although the efferent loop is involved in 75 per cent of cases
  182. 182. COMPLICATIONS OF GASTRIC SURGERY • Bezoars – after Billroth I and II procedures, especially when these are accompanied by vagotomies. – Gastric bezoars are more common after the Billroth I procedure, and those in the small bowel after Billroth II anastomoses. – usually phytobezoars related to an improper diet postoperatively Gastric bezoar. Large mass in stomach – solidified retained ingested fibrous material mixed with air in the patient after a Billroth II anastomosis
  183. 183. COMPLICATIONS OF GASTRIC SURGERY • Primary gastric carcinoma – occasionally develops in the gastric remnant – Incidence - 0.3–11 per cent. – approximately 1 per cent of all gastric cancers. – the patients have a relatively high incidence of atrophic gastritis. – Billroth II > Billroth I Wall thickening at the anastomosis site Post Bilroth II anastomosis
  184. 184. • On upper gastrointestinal examination, these tumours may have several appearances. • They may appear as a lack of distensibility of the gastric remnant. • Obstruction, either at the stoma or at the gastro-oesophageal junction, may be seen. • A pattern of enlarged rugae with intraluminal masses or gastric ulcer formation may also be seen. Gastric cancer after Billroth II anastomosis. There is narrowing, irregularity and lack of distensibility around the anastomosis
  185. 185. Classification • Congenital • Inflammatory • Infectious • Positional • Vascular • Trauma • Foreign body • Miscellaneous • Post surgical • Neoplastic
  186. 186. Benign Tumors • Polyps – Non neoplastic • Hyperplastic polyps • Hamartomatous polyps • Retention polyps – Neoplastic • Adenomatous polyps • Villous polyps • Lipoma • Neural tumors • Mesenchymal tumors
  187. 187. Gastric Polyps • Gastric polyps are the most common benign gastric tumours.
  188. 188. • They can be broadly divided into non-neoplastic and neoplastic polyps. • Non-neoplastic polyps include: – Hyperplastic, hamartomatous, and retention polyps • Neoplastic polyps include – Adenomatous and villous polyps.
  189. 189. Hyperplastic polyps • most common benign neoplasms of the stomach. • NOT considered to have malignant potential • but do occur more commonly in patients who have other risk factors for developing gastric malignancy, such as atrophic gastritis, and in patients with gastric resections and bile reflux gastritis.
  190. 190. • Radiographically, hyperplastic polyps are round, smooth sessile lesions. • They are usually multiple and of uniform size (< 1 cm). • They are most common in the fundus and body of the stomach. Hyperplastic polyps in the body of the stomach – small, sessile and uniform in size
  191. 191. Multiple hyperplastic polyps: a Double-contrast barium meal showing multiple filling defects in the stomach due to hyperplastic polyps and (b) endoscopic view of hyperplastic polyps in a different patient
  192. 192. Fundic gland polyps • variant of hyperplastic polyps believed to be hyperplastic fundal glands • not found in the antrum. • These are identified in up to 40 per cent of patients with familial adenomatous polyposis coli. Fundic gland polyps morphologically identical to hyperplastic polyps predominate in the fundus as shown in this patient with familial adenomatosis coli
  193. 193. Non neoplastic polyps • Hamartomatous polyps are sessile or pedunculated, usually less than 2 cm in diameter and are associated with Peutz- Jeghers syndrome. • Retention or inflammatory polyps are very rare such as associated with Cronkhite-Canada syndrome.
  194. 194. Adenoma • usually solitary • can be broad base or pedunculate • have a lobulated appearance with a smooth or irregular contour. • They are most commonly found in the antrum. • On double-contrast barium meal they have smooth circular outline, with the stalk seen en face overlying the head of the polyp – the “Mexican hat sign” Gastric adenoma: Double-contrast barium meal shows an adenoma as seen en face – “Mexican hat sign”
  195. 195. (A) Mexican hat. (B) Radiograph of an upper gastrointestinal series demonstrates a pedunculated gastric polyp demonstrating a close resemblance to a Mexican hat.
  196. 196. Adenomatous polyps • Adenomatous polyps coexist with gastric carcinoma in 35% of cases and malignancy is detected histologically in 50% of adenomas larger than 2 cm (Tomasulo 1971). Biopsy-proven adenomatous polyp in the gastric antrum (arrow)
  197. 197. Villous polyps • Villous polyps carry a very high risk for malignancy. • They are characterised by numerous frond-like projections which give them a typical bubbly appearance on double-contrast barium meal.
  198. 198. Gastric lipoma • Gastric lipoma is rare and usually appears as a smooth submucosal mass (Maderal et al. 1984). Gastric lipoma: Double-contrast barium meal shows a perfectly smooth submucosal mass due to a lipoma
  199. 199. Neural Tumours • 5–10% of benign gastric tumours (Hoare and Elkington 1976). • majority are nerve sheath tumours (neurinomas, schwannomas or neuromas). • Mostly benign, but occasional sarcomatous changes • CT - submucosal masses (with or without ulceration) that are indistinguishable from other mesenchymal tumours Biopsy-proven schwannoma. There is a submucosal soft tissue mass that shows only minor enhancement but a preserved and strongly enhancing mucosa (arrow). Note that the perigastric fat plane around the tumour is clear
  200. 200. Mesenchymal lesions • second most common type of polypoid lesion in the stomach after hyperplastic polyps. • Mesenchymal tumours of the gastrointestinal tract are referred to as gastrointestinal stromal tumours (GISTs) and include most lesions previously designated leiomyoma, leiomyoblastoma and leiomyosarcoma. • Approximately 70 per cent of GISTs occur in the stomach and most (70–90 per cent) are benign.
  201. 201. • Submucosal tumours, including GISTs and true leiomyomas account for about 90 per cent of all the gastric mesenchymal tumours. • Most of the tumours are small and are discovered incidentally during evaluation for unrelated problems. • Ulceration becomes more common as the lesions grow to >2 cm in size and symptoms, including epigastric pain and gastrointestinal bleeding, become more common.
  202. 202. • Radiographically the tumours appear as discrete submucosal masses typified by a smooth mucosal surface with borders forming right or slightly obtuse angles to the adjacent mucosa. • En face, the preservation of a normal areae gastricae pattern over the mass confirms the presence of normal mucosa and the extramucosal location of tumour. • When there is ulceration it is usually seen as a central collection of barium in a smooth or slightly lobulated mass. This is sometimes called a ‘target’ or ‘bulls-eye’ lesion. • Leiomyomas occasionally contain coarse mottled calcifications Leiomyoma adjacent to the gastro-oesophageal junction shown on CT as a smooth soft tissue mass in the contrast-filled stomach
  203. 203. Leiomyoma of the stomach. Double Contrast barium study (a) shows a well delineated smooth mass arising from the lesser curve of the stomach. Endoscopic-ultrasound (b) demonstrates a massive lesion which does not penetrate through the gastric wall. Biopsy revealed a benign leiomyoma
  204. 204. • 15 per cent – grow predominantly outside the stomach (exogastric) • < 5 per cent of cases – have an intra- and extraluminal growth pattern (‘dumbbell’). • Occasionally they are pedunculated – may obstruct the pylorus or duodenum or – act as the lead point of an intussusception.
  205. 205. An endogastric GIST arising from the posterior wall of the stomach. Note the intraluminal position with relatively acute angles to the adjacent gastric wall, as well as the heterogeneous attenuation An exogastric GIST arising from the posterior wall of the stomach. Note the more obtuse angle it forms with the body of the stomach and again a heterogeneous attenuation pattern. The size of this lesion together with the lack of definition of its margin suggest that this is frankly malignant
  206. 206. Malignancy?? • 10 per cent are malignant. • Unfortunately, the prediction of malignancy is difficult even by histological criteria. • GISTs are classified by their estimated risk of recurrence and metastasis into low- or high-risk categories. • Imaging findings contribute importantly to the assessment of risk of malignancy. • A favourable prognosis is associated with – tumour size <5 cm and – lack of infiltration into adjacent organs. – Gastric GISTs > distal GI tract GISTs – low mitotic index (<2/10 high-power fields), – low proliferation index and – DNA-diploidy in the G-2 peak by flow cytometry.
  207. 207. MALIGNANT NEOPLASMS • Gastric carcinoma and lymphoma are the most common malignant neoplasms of the stomach. • Each of these has a variable radiographic appearance, with some overlap of radiographic signs. • Other malignant neoplasms are considerably less common.
  208. 208. Gastric Carcinoma • more prevalent in Japan than elsewhere. • A difference in diet is the most strongly implicated reason for this occurrence • most gastric cancers are detected at an advanced stage due to the nonspecific and insidious nature of symptoms. • The incidence of gastric cardia tumours has increased while the incidence elsewhere in the stomach has decreased or remained stable
  209. 209. Early gastric carcinoma • defined as gastric carcinoma that is limited to the mucosa and submucosa with or without associated lymphadenopathy (Gore et al. 1997).
  210. 210. • At double-contrast barium meal early gastric cancer appears as: – an elevated polypoid lesion (type I), – superficial plaque-like lesion (type II), or – shallow irregular ulcer with adjacent nodular mucosa and associated amputation of radiating folds (type III) (Gold et al. 1984).
  211. 211. Early Gastric Cancer. Double Contrast barium study (a) shows slight distortion of normal mucosal folds on the posterior wall of the antrum of the stomach. Endoscopy (b) demonstrates the non-depressed lesion, with distortion of the normal gastric mucosal pattern. Histopathology confirmed early gastric cancer
  212. 212. Advanced gastric carcinoma • Tumours most frequently present as large, irregular masses that may or may not be ulcerated.
  213. 213. • The margins of the masses may exhibit a shelf, and form an acute angle with the gastric wall, indicating the mucosal origin of the tumour. • This may become less obvious as the tumour enlarges. • As the mucosa is primarily involved by the tumour, the surface is generally irregular. • When the antrum is primarily involved by tumour, it may be severely narrowed or obstructed. Large circumferential mass in the body of the stomach with a shelf at the proximal margin sharply demarcating the cancer from the proximal stomach.
  214. 214. Gastric carcinomas may demonstrate several forms at CT: a thick walled ulcer polypoid mass infiltration of the gastric wall with reduced distension and loss of mucosal detail
  215. 215. • Sometimes, the stomach can be diffusely infiltrated by a scirrhous tumour resulting in a linitis plastica or “leather bottle” appearance (Low et al. 1994; Gore et al. 1997). Gastric carcinoma: Infiltrative gastric carcinoma producing a linitis plastica or “leather bottle appearance”
  216. 216. Scirrhous gastric carcinoma. Gastroscopy revealed irregular mucosal folds in the body of the stomach (a). Biopsies were negative and follow-up examinations with a barium meal (b) and ultrasound (c) revealed narrowing of the lumen, typical irregular folds, and a thickened gastric wall
  217. 217. Linitis plastica • descriptive term for a tumour of the stomach, usually a carcinoma, which is diffusely infiltrating with considerable fibrosis. • Radiographically this usually appears as a narrowed, rigid stomach.
  218. 218. scirrhous carcinoma with linitis plastica appearance. Poor distensibility of the stomach is shown on the barium study (a) and wall thickening confirmed by CT
  219. 219. • Linitis plastica appearance caused by eosinophilic gastroenteritis. • The clue to the diagnosis relates to the infiltration extending into the duodenum, although this was not appreciated at endoscopy
  220. 220. Staging of Gastric Carcinoma • The TNM classification system • Two important factors influencing survival in resectable gastric cancer are – depth of invasion and – regional lymph node involvement. • Although such imaging studies such as the double-contrast upper GI, CT and MRI are useful in examining a patient with suspected gastric carcinoma, and possibly detecting lymph node involvement, their usefulness remains limited for staging.
  221. 221. Preoperative tumour staging • most commonly performed using CT, although endoscopic US is used in some centres primarily for evaluating the depth of gastric wall invasion. • In a patient with nonspecific abdominal symptoms, the gastric neoplasm may first be detected on a ‘routine’ CT. • On CT, gastric cancer may present as – focal wall thickening with or without ulceration, – mass or – diffuse wall thickening. • In a well-distended stomach, a wall thickness of >1 cm is considered abnormal. • Tumours may exhibit abnormal contrast enhancement of the gastric wall and loss of the normal multilayered wall pattern.
  222. 222. • Using CT, the tumour may not only be diagnosed, but may also be staged. • Wall thickness, the presence or absence of regional lymphadenopathy, adenopathy in the left gastric, porta hepatis and peripancreatic area and the presence or absence of liver metastases can be evaluated. • The pancreas, left lobe of the liver, spleen and transverse colon may all be involved by direct extension of tumour. • Distant or diffuse intraperitoneal metastatic disease may also be detected.
  223. 223. TNM Staging
  224. 224. • Advanced gastric cancer (pT2). • Coronal reformation shows focal wall thickening of the antrum with marked enhancement of the mucosal layer (arrows). At histology, the outer layers of the muscularis propria were intact, whereas the inner layers were infi ltrated. The subtle irregularities of the mucosal surface correspond to ulceration at histology. Note the clear fat plane around the tumour. • Large carcinoma at the lesser curvature. Note that there is an area with irregular delineation of the tumour from the surrounding fat (arrowhead), which corresponds to a desmoplastic reaction at histology. There are two slightly hyperenhancing lymph nodes adjacent to each other (arrow); both proved to be metastases positive at histology.
  225. 225. • Advanced gastric cancer (pT3). • A large polypoid carcinoma with gross infiltration of the perigastric fatty tissue (arrows). • Oblique coronal reformation tilted posteriorly to display the corpus and fundus of the stomach and distal oesophagus. There is a large tumour (T) that protrudes from the posterior wall into the lumen and appears as a filling defect within the water-filled stomach. Note the increased density stranding in the perigastric fat (arrow) and the oval lymph node that proved to be hyperplastic at histology (arrowhead)
  226. 226. • Advanced gastric cancer (pT4). • Advanced gastric cancer of the posterior wall of the body that infiltrates the tail of the pancreas (arrow). • Coronal reformation of the posterior portions of the abdomen. Large gastric cancer with obliteration of the fat plane and thickening of the colonic wall (arrow). At histology, the transverse colon was infiltrated.
  227. 227. N STAGING Regional lymph nodes are considered involved when the short-axis diameter is >6 mm for the perigastric lymph nodes and >8 mm for the extraperigastric lymph nodes Other criteria for malignant involvement include: Nearly round shape (L/T ratio <1.5) Fatty hilum eccentric or missing Strong or heterogeneous enhancement
  228. 228. M Staging
  229. 229. Gastric lymphoma • stomach – most frequent site of gastrointestinal lymphoma. • Mostly of the non-Hodgkin's type. • Gastric involvement may be primary, due to direct extension from involved lymph nodes, or part of generalized disease. • There is no anatomic predilection but when the antrum is involved duodenum is often affected.
  230. 230. MALT lymphoma • type of non-Hodgkin's lymphoma that occurs in the lung, thyroid and salivary glands and intestine, but the stomach is by far the most common site. • Normally, there is no lymphoid tissue in the gastric mucosa. • Helicobacter pylori, the only common bacterial antigen in the stomach, results in an accumulation of gastric mucosa-associated lymphoid tissue. • Double-contrast upper gastrointestinal studies demonstrate rounded, often confluent nodules of varying size which can be difficult to distinguish from gastritis or leukaemic infiltration (Levine et al. 1996; Yoo et al. 1998; Brown et al. 2000). • Depressed lesions and thickened fold may also be seen
  231. 231. Gastric MALT lymphoma showing marked thickening of the posterior wall of the stomach (a). Note the bilateral shrunken kidneys in this renal transplant patient. There is also marked extranodal lymphadenopathy in the region of the omentum, suggesting that the underlying condition is more likely to be high-grade (b)
  232. 232. Primary Gastric Lymphoma • no typical radiographic appearance, and may mimic any of the appearances of gastric carcinoma. • At double-contrast barium meal gastric lymphoma may demonstrate – an infiltrative appearance with thickened broad tortuous mucosal folds, – a circumscribed mass growing inside or outside the lumen of the stomach, or – large irregular ulcers (Sherrick et al. 1965; Menuck 1976).
  233. 233. • There are four gross pathological types of gastric lymphoma (Fischback et al. 1992): – Infiltrative gastric lymphomas manifest as a focal or diffuse enlargement of rugal folds due to submucosal spread of tumour (Fig. 6.2.11a). – One or more ulcerated lesions characterize ulcerative gastric lymphoma (Fig. 6.2.11b). – Polypoid gastric lymphomas are characterized by intraluminal masses that may simulate polypoid carcinomas (Fig. 6.2.11c). – Multiple submucosal nodules ranging in size between several millimetres and several centimetres characterize the nodular form of gastric lymphoma (Fig. 6.2.11d).
  234. 234. Infiltrative Ulcerative Polypoid Nodular
  235. 235. Lymphoma v/s Carcinoma • CT may be helpful in differentiating gastric lymphoma from carcinoma, although at times the appearance of these two entities may be identical. • Direct spread of disease or invasion of the stomach from enlarged regional lymph nodes may be observed, and may sometimes by helpful in differentiating these two processes.
  236. 236. Gastric carcinoma Lymphoma Wall thickening Less thick, mean = 1.8cm homogeneously thick Very thick, mean = 4 cm focally thick Perigastric fat planes May be obliterated Usually preserved Regional adenopathy Common Common Extent of adenopathy Does not extend below renal vein May extend below level Less bulky Large bulky nodes Extent Does not commonly involve duodenum May involve duodenum
  237. 237. Tumours of mesenchymal origin (gastrointestinal stromal tumours) • Most malignant mesenchymal tumours seen in the stomach are malignant GIST tumours many of which are called leiomyosarcomas. • They are indistinguishable from their benign counterparts radiographically, and frequently histologically, except for size. • If the size of the mass is >5 cm, malignancy should be strongly considered. • As a result of the large size of these tumours, they frequently outgrow their blood supply and ulcerations are therefore common. • Tumours may arise from any of the mesenchymal elements of the gastric wall, including the neural elements. • These are all radiographically indistinguishable from one another.
  238. 238. GIST response to Glivec therapy. The initial CT demonstrates a huge predominately exophytic GIST arising from the greater curve of the stomach (a). Note the metastasis in the liver. Following three months of Glivec therapy, there has been dramatic reduction in the size of the main tumour and it is of lower attenuation (b). However, there has been relatively little change in the appearance of the metastasis
  239. 239. Metastatic Disease • They may result from – direct spread such as from a carcinoma of the pancreas or kidney or colon or – from a haematogenous route.
  240. 240. • The most common primary tumours that metastasize to the stomach are breast, malignant melanoma and lung. • Blood-borne metastases to the stomach appear radiographically as gastric wall lesions. • Initially these can be seen as small intramural masses, usually multiple, that are indistinguishable from benign disease.
  241. 241. Metastasis to the stomach. Double Contrast and Single Contrast barium studies (a) demonstrate a villous type tumour arising from the lesser curve aspect of the antrum, confirmed at endoscopy (b). Biopsy revealed a metastasis from breast cancer
  242. 242. • These may contain central ulcerations, having a bulls-eye appearance. – most frequently seen in metastatic melanoma, lymphoma and Kaposi's sarcoma. • As these lesions grow, the aetiology becomes apparent. • Breast carcinoma may produce a linitis plastica-type appearance, indistinguishable from primary gastric carcinoma.
  243. 243. Angiography of the Stomach • DSA to examine coeliac axis and SMA • Bowel should be paralyzed • Adequate breath hold
  244. 244. Indications • Gastrointestinal Bleeding • Tumors
  245. 245. Gastrointestinal Bleeding • Commonest indication • Endoscopy – primary indication and performed prior to angiography
  246. 246. • Active bleeding is identified angiographically when contrast medium extravasates into the bowel lumen. • This finding may be absent if the bleeding is intermittent and other more indirect angiographic signs such as – an aneurysm, – early venous return, – vascular irregularity or truncation should be sought.
  247. 247. • For many years it has been accepted that the identification of a bleeding source requires a blood loss at a rate of 0.5 ml/min (Nusbaum and Baum 1963), but in general the chance of localising the site of bleeding is greater with a higher rate of blood loss. • The timing of angiography is evidently critical and a good ‘rule of thumb’ is that – the patient’s pulse should be greater than 100 beats/min and – the systolic blood pressure less than 100 mmHg, to maximise the chance of localisation.
  248. 248. • The most frequent causes of gastric bleeding are: – peptic ulcers, followed by – Iatrogenic causes, e.g. following biopsy or surgery, and – aneurysms. • The role of angiography in the upper gastrointestinal tract is focussed more on therapy by embolization than purely diagnosis, particularly in elderly patients with high co-morbidity who are poor surgical candidates
  249. 249. Aneurysms • Visceral aneurysms are uncommon and most frequently involve the splenic artery. • Contrast enhanced CT is usually performed and this may reveal a haematoma and sometimes the aneurysm itself, which is a useful guide for subsequent angiography.
  250. 250. Tumours • Embolization are useful in inoperable primary leiomyosarcomas, which can cause severe bleeding, and large invading pancreatic neuroendocrine tumours.
  251. 251. Zollinger-Ellinson Syndrome • Angiography is indicated for preoperative localisation of the tumour, which can be single or multiple. • preoperative localisation of the tumour • Historically, the sensitivity of angiographic localisation has been increased by the use of intra-arterial injection of secretin (Doppman et al. 1990). • This has now largely been superseded by using calcium gluconate, which has been demonstrated to be a highly sensitive and specific alternative (Turner et al. 2002).
  252. 252. RADIOLOGICAL INTERVENTION IN THE STOMACH
  253. 253. Introduction • Until recently interventional procedures for lesions of the gastro-oesophageal junction, the stomach and the duodenum have been the domain of the endoscopist. However, difficult or failed endoscopic cases are frequently referred for radiological management.
  254. 254. Patient Preparation • Ensure adequate hydration to maintain renal function, and • Anaemia and clotting abnormalities need to be corrected. – haemoglobin > 100 g/l, – platelets > 50.000/ μl, – PT-ratio (international normalised ratio, INR) and – APTT ratio ≤ 1.3. • Proper assessment of sedation risk,
  255. 255. The Pre Operative Stomach • Main indication: gastric outlet obstruction • Stent insertion is cheaper and results in quicker recovery than open gastro-jejunostomy (maetani et al. 2004; mittal et al. 2004) • The proximal margin of the lesion is assessed either endoscopically or fluoroscopically. • Need for fluoroscopy is imperative to assess the distal margin of the obstruction
  256. 256. Obstructing pancreatic tumour: Fluoroscopic stent placement in prone position. Injection of contrast shows an irregular stricture at the pylorus (arrow). b The stricture is crossed with a looped, stiff hydrophilic wire Aqualiner
  257. 257. c Injection of air and contrast shows a possible further stricture in D2 (arrow). d The hydrophilic wire is exchanged for a heavy duty wire, note the junction of the flexible wire tip with the stiff shaft (arrow). The stent delivery system (arrowheads) is positioned, allowing for stent shortening deployment.
  258. 258. e A Niti-S stent immediately after deployment. The stent is in excellent position, with an initially distorted appearance. f After 24h the nitinol skeleton has regained its original configuration (patient supine)
  259. 259. Obstruction of the gastric outlet: using a doubled- up wire is the safest way to traverse a stricture, avoiding perforation as well as exiting through the sides of an existing stent.
  260. 260. The Post-Operative Stomach • The procedure for stenting anastomotic tumour recurrence after Billroth I gastrectomy is exactly as described in the native stomach. • Similarly tumour recurrence after Polya (Billroth II) gastrectomy can be treated with stenting of the gastro-enterostomy
  261. 261. • a–d. Recurrent tumour obstructing the efferent loop of a Polya (Billroth 2) gastro-jejunostomy. • The stricture (arrowheads) is easily identified, a through-the- scope delivery system passed (arrow) and an uncovered Hanaro nitinol stent deployed. Initial limited expansion will increase over the space of several days
  262. 262. Gastrostomy • Percutaneous gastrostomy for feeding support is a procedure for which there has been enormous demand since it was first described in children in 1980 (Gauderer et al. 1980). • Before this, gastrostomy was a surgical procedure, which required opening the abdomen and stomach in order to place the feeding tube.
  263. 263. Percutaneous Endoscopic Gastrostomy (PEG) • The quickest and simplest way to place a gastrostomy is with endoscopic support. • The endoscope is passed into the stomach, which is inflated with air and a point in the body or antrum is chosen for entry.
  264. 264. • occasionally fails because of – unsuccessful endoscopic access or – inability to determine a safe point of puncture (Wollman and D‘Agostino 1997; Laasch et al. 2003). • This latter occurs most commonly in overweight patients or when the left lobe of the liver lies low in the epigastrium covering access to the stomach
  265. 265. Fluoroscopic Gastrostomy • Inserted directly through the skin into the stomach OR • advanced through the mouth, oesophagus and stomach and brought out through the abdominal wall (as in PEG)
  266. 266. Radiologically Inserted Gastrostomy (RIG) • Also termed percutaneous radiologic gastrostomy (PRG), allows a tube to be placed directly percutaneously into the stomach (Preshaw 1981; Wills and Oglesby 1983). • Advantages: – reduced infection rate as the tube is not contaminated by oral flora, – avoiding the risk of stoma metastasis from upper GI tumour seeding and – provides the option to perform this under local anaesthesia in high-risk patients (e.g. motor neurone disease).
  267. 267. a,b. Müller-Brown gastropexy T-fasteners A metal bar (arrow) is attached to a suture with a cotton wool bud and aluminium tubes for crimping (arrowheads) on the outside of the patient. The bar is inserted into a slot in the delivery needle. c After local anaesthesia the stomach is punctured with the slotted needle containing the T-fastener. Intragastric position is confirmed and the T-fastener dislodged from the needle with a pusher (arrow).
  268. 268. Per-oral Image-Guided Gastrostomy (PIG) • a hybrid of PEG and RIG • outcomes superior to both methods (Laasch et al.2003) • It can be used as a routine alternative to PEG. • also appropriate for use where endoscopic gastrostomy has failed but RIG is not necessarily indicated. • The procedure is simple and does NOT require the use of gastropexy sutures or the use of an endoscope.
  269. 269. a Over-the-wire push gastrostomy tubes: A, assembled 20-Fr Corflo gastrostomy (Merck). B, 14- Fr MicKey gastrostomy (Vygon). The tube itself is joined (arrow) to a long tapered dilator shaft (arrowheads). b The stomach is inflated through a naso-gastric tube (arrow).
  270. 270. c The puncture needle (arrow) is inserted in a straight line below the cardia. d Over a wire the needle is exchanged for a valved vascular sheath (arrow).
  271. 271. e A Headhunter 1 catheter (arrow) is advanced onto the cardia. In this case cannulation is made easy by the presence of an axial hiatus hernia (arrowheads). f Catheter and wire (arrow) are manipulated up the oesophagus following the line of the nasogastric tube (arrowhead). g Push-gastrostomy in situ

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