Plain picture in acute abdomen


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  • Subcostal plane : a plane corresponding to a line drawn joining the lowermost bony point of the rib cage - usually 10th costal cartilageThis corresponds the level of the body of the L3 vertebra. The origin of the superior mesentericartery and 3rd part of the duodenum lie on this planeTrans-tubercular plane : a plane corresponding to a line uniting the two tubercles of the iliac crests.The upper border of the L5 vertebra corresponds to this plane long with the confluence of the common iliac veins (i.e. commencement of the Inferior Vena Cava).
  • Pneumoperitoneum is detected in 76% of cases in erect film, but when a left lateral decubitus film is added the sensitivity is raised to 90%.
  • Triangular in shape, concave lateral border, positioned inferior to the right 11th rib, positioned superior to the right kidney
  • Coined by leorigler,american radiologist. Air is present on both sides of the intestine, i.e. when there is air on both the luminal and peritoneal side of the bowel wall.
  • The oval radiolucency seen in the football sign (Figure) represents massive pneumoperitoneum, which distends the peritoneal cavity. In the supine position, free air collects anterior to the abdominal viscera, producing a sharp interface with the parietal peritoneum and thereby creating the football outline. The pneumoperitoneum may outline the falciform ligament, which is seen as a faint linear opacity situated longitudinally within the right upper abdomen
  • Cupola is an inverted cup or a “dome”.. Seen in erect film.
  • Subdiaphragmatic fat is an extension of posterior pararenal fat, a normal finding.
  • Bowel loop, usually the transverse colon is interposed between the liver and the hemidiaphragm resulting in pain. Features that suggest a Chilaiditi syndrome (termed the Chilaiditi sign) include:1.gas between liver and diaphragm,2.rugal folds within the gas suggesting that it is within bowel and not free
  • Mechanical as a complication to peptic ulcer disease, antral carcinoma, extrensic compression over duodenum.Paralytic ileus – commonly post-operative, electolyte disturbance due to metabolic conditions like hepatic or diabetic coma,,, Inflamamtion like pancreatitis, cholecystitis or trauma.Drugs.
  • Post-surgical adhesions account for 60% of cases of acute SBO, can occur within 4wks of surgery.Or may present as chronic obstruction decades latter.
  • Factors affecting radiographic appearance_- 1. Duration of obstruction,2. Frequency of emesis 3. Use of nasogastric tube.
  • Three or more small bowel fluid levels longer than 2.5 cm are abnormal and indicates dilated small bowel, usually with stasis.
  • The obliquely oriented row of air bubbles represents small amounts of air trapped between the valvulaeconniventes along the superior wall of predominantly fluid-filled, dilated small-bowel loops. The meniscal effect of the surrounding fluid gives the trapped air an ovoid or rounded appearance.
  • Ileus means disruption of the normal propulsive activity of gastrointestinal tract.
  • Presence of gas in colon with decreased dilatation may give clue to diagnosis of paralytic ileus.
  • The appearance of generalisedadynamicileus is quite characteristic. The large and small bowel are extensively air filled but not dilated. That is the large and small bowel "looking the same“.
  • duodenum / stomach : leading to gastric outlet obstruction (Bouveret's syndrome)
  • Usually an elderly patient presents with acute onset abdominal pain with bloody diarrhoea.
  • Caecal Volvulus-Dilated loop of large bowel (cecum) in the left upper quadrant with little gas is seen distal part
  • The ahaustral margin can often be indentified overlapping respectively the lower border of the liver shadow(the liver overlap sign), the haustrated, dilated descending colon (the left flank overlap sign) and the left side of the pelvis (the pelvic overlap sign).The top the volvulus reaches very high in the abdomen (above 10th rib) with the apex on left side.
  • The classic findings are colonic dilation, nodular haustral thickening, and thumb printing. In this radiograph the thickening is most pronounced in the transverse colon.
  • Inflammatory exudate in acute pancreatitis that extends intothe phrenicocolic ligament. Infiltration of the phrenicocolic ligament results in functional spasm and/or mechanical narrowing of the splenicflexure at the level where the colon returns to the retroperitoneum. This transition point, or cutoff, is further accentuated bydistention of the intraperitoneal transverse colon from thefocal adynamicileus, which is also a result of the underlyinginflammatory process. This appearance can mimic a truecolonic obstruction
  • Air in the wall (blue arrows) of the gallbladder. There is also a lucency within the lumen of the gallbladder suggesting air inside the lumen. Just superior to the gallbladder is another collection of air (red arrow) that represents a pericholecystic abscess. The yellow arrow points to PEG tube in the stomach.
  • The severe pain which accompanies renal colic frequently leads to air swallowing and this, together with an associated paralytic ileus, frequently results in gas filled small and large bowel loops.
  • Emphysematous pyelonephritis. Patient with diabetes mellitus and sepsis. The left renal collecting system and ureterare distended and gas filled. There are also multiple dense gallstones in the gallbladder.
  • The mere presence of of an aortic aneurysm does not indicate dissection or leak. However, a soft tissue mass identified outside the calcified wall of an aneurysm or bowel gas displaced anteriorly or obscured psoas or renal outline suggests a leak.
  • Plain picture in acute abdomen

    1. 1. Plain picture in acute abdomenModerator-Dr (Prof). R. K. Gogoi Presenter: Dr. Sarbesh Tiwari
    2. 2. INTRODUCTION• Acute abdomen refers to presence of severe abdominal pain developing suddenly or over a period of several hours.• Most frequent reasons for presentation at the emergency department (ED).• It requires a clinician to make an urgent therapeutic decision. 2
    3. 3. Plain Radiography• Plain abdominal radiography is traditionally the first radiological investigation in acute abdomen• Interpretation of plain films presents with formidable challenge because though specific diagnosis can be made, not infrequently the appearance are non specific and misleading. 3
    4. 4. Basic radiographsA supine Abdomen radiograph & Basic standard radiographs Erect Chest x ray Erect abdomen Left lateral decubitus (right side raised) are taken to add information Patient to remain in given position – 10 minutes 4
    5. 5. Erect chest radiograph:o Small pneumoperitoneum can be detectedo Various chest conditions may mimic anacute abdomen.o Acute abdominal conditions may becomplicated by chest pathologyo Even a normal chest radiograph acts as abaseline and helps in detection of postoperative complication. 5
    6. 6. Chest Conditions that mimic acute abdomen 1. Pneumonia 2. Myocardial Infarction 3. Pulmonary Infarction 4. Congestive cardiac failure 5. Pericarditis 6. Leaking or dessecting thoracic aortic aneurysm 7. Pneumothorax 8. Pleurisy 6
    7. 7.  Abdominal radiographs: (kv:60-65, shortexposure time)o Supine abdominal radiograph- Distribution of gas Calibre of bowel Displacement of bowel Obliteration of fat lineso Erect abdominal radiograph- fluid level and freegaso Horizontal-ray films( erect or lateral decubitus)-free intra- abdominal air, fluid levels 7
    8. 8. TECHNIQUE standard projection • supine with kneeAnteroposterior supine slightly flexed. • centered at iliac crest. • Exposure during expiration • Low kV (60-75 kV) • Short exposure time to avoid motion • Both the lung bases and the pubic symphysis included. 8
    9. 9. Supplemental projections Abdomen AP erect • Ideally, tilting x ray table with potter Bucky diaphragm used to reduce distress to patient • 14”- 17” film, high mA, short exposure time, increased 7-10 kVp over supine. • Centered just above umbilicus in midline 9
    10. 10. ADDITIONAL PROJECTIONS• Prone, Oblique, Lateral • For better definition and localization of • mass lesions • calcifications • herniations• A prone radiograph is useful when distal colonic obstruction is suspected. 10
    11. 11. RADIATION EXPOSURE• One PP abdomen exposes a patient to 0.7 mSv of radiation, equivalent to 35 chest radiograph.• Gonadal shielding should be used if gonads lie within 5 cm of the primary beam, if clinical objective is not compromised 11
    12. 12. 12
    13. 13. NORMAL GAS PATTERN• Stomach - always• Small bowel - 2 or 3 loops of non-distended bowel - normal diameter = 2.5 cm• Larger bowel - in rectum or sigmoid colon - always
    14. 14. NORMAL FLUID LEVELS• Stomach - always (except supine film)• Small bowel - 2 or 3 levels possible• Large bowel - none normally
    16. 16. • Pneumoperitoneum refers to the presence of free gas within the peritoneal cavity• Almost always caused by perforation of hollow viscus.• Perforated duodenal ulcer is the most frequent cause 18
    17. 17. CAUSES1. Perforation• Peptic ulcer disease• Inflammation- Diverticulitis, toxic megacolon,necrotizing enterocolitis• Infraction• Pneumatosis coli- The cyst may rupture• Maliganacy.• Mechanical perforation following trauma2. Iatrogenic• Abdominal surgery• Peritoneal dialysis3. Pneumothorax- due to congenital pleuroperitoneal fistula. 194.Introduction per vaginum- e.g. douching
    18. 18. RADIOGRAPHY• Optimal radiographic technique is important.• At least 2 radiographs, • a supine abdominal radiograph and • either an erect chest image or a left lateral decubitus image.• The patient should remain in position for 5-10 minutes before a horizontal-beam radiograph is acquired.• As minimal as 1ml of free gas could be detected by proper technique. 20
    19. 19. Signs in pneumoperitoneum Erect chest radiograph reveals free gas between the liver and both does of diaphragm. 21
    20. 20. Left lateral decubitus film showing gas between the liver and abdominal wall. 22
    21. 21. Signs of pneumoperitoneum of supine radiograph • Right upper quadrant gas Peri hepatic Sub hepatic Morrison’s pouch • Fissure for ligament teres • Rigler’s (double wall sign) • Ligament visualization Falciform Umbilical inverted ‘V’ sign • Triangular air • The cupola sign • Football or air dome • Scrotal air in children 23
    22. 22. Gas in subhepatic spaceSupine abdominal radiograph shows an elliptical collection of air within the subhepatic space 24
    23. 23. Doges cap sign• Doges Cap sign refers to free air in Morrisons pouch.• Morrisons pouch is normally a potential space between the right kidney and the liver 25
    24. 24. Triangular gas shadow superior to kidney and postero- inferior to 11th rib 26
    25. 25. Rigler’s signRiglers sign refers to the appearance of the bowel wall onplain film when it is outlined by intraluminal and extraluminalair .The extra luminal air is free peritoneal gas 27
    26. 26. Falciform ligament visualizationVisualization of Falciform ligament by free gas on either side of 28 the ligament
    27. 27. Football sign• The football sign likens the massively air- filled peritoneum to an American football• In the supine position, free air collects anterior to the abdominal viscera, producing a sharp interface with the parietal peritoneum and thereby creating the football outline 29
    28. 28. 30
    29. 29. Double Bubble SignTwo collections of overlapping gas- one of these collections is subdiaphragmatic free gas and the other is normal gas within the fundus of 31the stomach
    30. 30. The Cupola SignAn arcuate collection of free intraperitoneal air beneath the centraltendon of diaphragm. The superior border is well defined (arrows) 32 compared with the inferior extent of the collection.
    31. 31. The Triangle SignThe triangle sign refers to small triangles of free gas that can typicallybe positioned between the large bowel and the flank(black arrow) 33
    32. 32. CONDITIONS SIMULATING PNEUMOPERITONEUM 1. Chilaiditi’s syndrome-intestine between liver and diaphragm 2. Subphrenic abscess 3. Curvilinear supradiaphragmatic pulmonary collapse 4. Subdiaphragmatic fat 5. Cyst in pneumatosis intestinalis 6. Sub pulmonary pneumothorax 34
    33. 33. CONDITIONS SIMULATING PNEUMOPERITONEUM Chilaiditi‟s syndrome- intestine between liver and diaphragm 35
    34. 34. CONDITIONS SIMULATING PNEUMOPERITONEUMRight sided subphrenic abscess 36
    35. 35. CONDITIONS SIMULATING PNEUMOPERITONEUM Large bulla at the base of the right lung mimics a large pneumoperitoneum 37
    37. 37. GASTRIC DILATATIONCauses1. Mechanical gastric outlet obstruction.2. Paralytic ileus3. Gastric volvulus4. Air swallowing. 39
    38. 38. GASTRIC VOLVULUSo Twisting of the stomach around its longitudinal or mesenteric axiso Organoaxial volvulus - Stomach rotates along its long axis and becomes obstructed, with the greater curvature being displaced superiorly and the lesser curvature located more caudally in the abdomen 40
    39. 39. • Mesenteroaxial volvulus --less common , occurs when the stomach rotates along its short axis, with resultant displacement of the antrum above the gastroesophageal junction 41
    40. 40. SMALL BOWEL OBSTRUCTION• Small bowel obstruction refers to any condition where the lumen of the small bowel is obstructed• The obstruction may be intrinsic (as with intussusception) or extrinsic (as with abdominal adhesions)• A small bowel diameter on plain film greater than 30mm is considered dilated 42
    41. 41. Clinical Presentation of SBO Abdominal pain Rapid onset of nausea and vomiting Belching Abdominal swelling Constipation and obstipation. Squealing bowel sounds (early obstruction) No bowel sounds (bowel wall muscular exhaustion) 43
    42. 42. SMALL BOWEL OBSTRUCTION• Extrinsic causes - adhesions( most common) - hernias - masses - congenital malrotations• Intramural causes - inflammatory strictures - ischaemia - primary small bowel tumours• Intraluminal causes - gall stones -foreign bodies 44
    43. 43. PLAIN RADIOGRAPH• Plain film Signs appear after 3-5 hours marked after 12 hours• Supine abdominal X-rays- dilated gas filled bowel loops (more than 2.5 cm) with little or no gas in colon• Erect films shows- multiple fluid level assuming a „„step-ladder apperance‟‟• „„String of pearls sign‟‟- - Seen in decubitus or upright film and is virtually diagnostic of SBO 45
    44. 44. markedly distended loops ofsmall bowel, with effacement Step ladder pattern of the Valvulae in the mid produced by air fluid abdomen levels in erect film 46
    45. 45. STRING OF PEARL SIGNLeft lateral decubitus radiograph of the abdomendemonstrates a row of small air bubbles (arrows), whichrepresents air trapped between the Valvulae Conniventes. 47
    46. 46. The coiled spring appearance only occurs in the dilated air-filled small bowel. It is most noticeable in the jejunum where the valvulae conniventes are closely spaced 48
    47. 47. GASLESS SMALL BOWEL OBSTRUCTIONGasless fluid filleddilated small bowelAll the air is absorbedDifficult to differentiatewith normal bowel loops 49
    48. 48. PARALYTIC ILEUS• lleus occurs from hypomotility of the gastrointestinal tract in the absence of mechanical bowel obstruction.• Causes- 1. Post operative ileus 2. Electrolyte imbalance 3. Sepsis 4. Generalised peritonoitis 5. Blunt abdominal trauma 6. Infiltration of mesentry by tumor 50
    49. 49. PARALYTIC ILEUS• Difficult to distinguish adynamic ileus from mechanical obstruction based on single radiograph• Degree of distension varies and features are not specific• Generalized distension- difficult to distinguish from low large bowel obstruction 51
    50. 50. 52
    51. 51. Differentiating SBO from Paralytic Ileus SBO Ileus Patient with prior Recent (hours) post- Etiology surgery weeks to years operative patient prior Pain Colicky Not a prominent feature Abdominal Frequently prominent May not be apparent distensionBowel sounds Usually increased Usually absentSmall bowel Present Present dilatationLarge bowel Absent Present dilatation 53
    52. 52. STRANGULATING OBSTRUCTION• Occurs when two limbs of a loop are incarcerated by a band or in a hernia, compromising the blood supply• Plain radiograph - soft tissue mass or pseudotumour -gas filled loops separated by thickened walls may resemble a large coffee bean - if gangrene occurs, lines of gas seen in the wall of the small bowel 54
    53. 53. Dilated small bowelloops with anobstructed bowel in theright inguinal canal. 55
    54. 54. GALLSTONE ILEUS• Mechanical intestinal obstruction due to impaction of gall stones in the intestine• Comprises about 2% of small bowel obstruction• Unusual complication of chronic cholecystitis• Impaction of gallstone in terminal ileum after passing through a biliary-enteric fistula• Average age of diagnosis is 70 years. 56
    55. 55. • The classic radiographic signs, described by Rigler• Rigler’s traid:- 1. Incomplete or complete SBO 2. Gas within gall bladder/bile duct 3. Ectopic location of gall stone 57
    56. 56. INTUSSUSCEPTION• It is the invagination of a segment of bowel ( intussusceptum) into the contiguous segment ( intussuscipiens)• Commonly seen in children below 2 years• Ileocolic segment involved in 90% cases• Colocolic and ileoileal intussusception may occur• Common in the ileum due to inflammation of the lymphoid tissue in Peyer’s patches 58
    57. 57. INTUSSUSCEPTION• In adults usually secondary to tumor of the bowel.• Results in small bowel obstruction• Crescent sign-Soft tissue mass, sometimes surrounded by a crescent of gas, most commonly in Rt.hypochondrium.• Target sign- two concentric circles of fat density lying to the rt. of spine.• Target sign twice as common as crescent sign 59
    58. 58. There is a prominent crescent sign in the left upper quadrant witha subtle target sign in right upper quadrant. 60
    59. 59. Intussusceptions in the leftupper quadrant on this plainfilm of an infant with painvomiting 61
    60. 60. SMALL INTESTINAL INFARCTION• Thrombosis or embolism of superior mesentric artery• FEATURES 1. Gas filled dilated loops with multiple fluid levels. 2. Thickened bowel loops owing to submucosal edema or hemorrhage. 3. Linear gas in wall streaks suggest gangrene. 4. Free gas if perforation. 5. Intra luminal gas in mesentric veins or portal vein in advanced cases. 62
    61. 61. Intramural gas withpositive rigler sign (due to intraperitoneal gas) suggests possibilty of intestinal infarction. 63
    63. 63. Large Bowel Obstruction• Dilated colon to point of obstruction• Little or no air in rectum/sigmoid• Little or no gas in small bowel, if ileocecal valve remains competent 65
    64. 64. Etiology• Mechanical obstruction 1. Carcinoma of colon (60%) 2. Diverticulitis (second most common) 3. Volvulus 4. Extrinsic compression• Paralytic ileus. AKA acute colonic psudo- obstruction, was first described by Ogilvie 66
    65. 65. LARGE BOWEL OBSTRUCTION-types • TYPE 1 A • Large bowel distension only- • Owing to competent ileocaecal valve. • Caecum at risk of perforation 67
    66. 66. LARGE BOWEL OBSTRUCTION-types • TYPE 1 B • Competent ileocaecal valve leading to caecal distension but also as a mechanical obstruction to small bowel • Caecum at risk of perforation. 68
    67. 67. LARGE BOWEL OBSTRUCTION-types • TYPE II • Large and small bowel distension • Incompetent valve 69
    68. 68. Large bowel Volvulus• Sigmoid colon and caecum - most common sites• If twist greater than 360 degrees, unlikely to resolve spontaneously.• The risk of vascular compromise more important than mechanical effects• Compound volvulus, involving interwining of two loops of bowel is rare, such as ileosigmoid knot. 70
    69. 69. CAECAL VOLVULUS• Torsion of the bowel around its own mesentery and often results in a closed-loop obstruction• Occurs due to development failure of peritoneal fixation.• Accounts for 2-3% case of intestinal obstruction and 11% cases of colonic volvulus. 71
    70. 70. The cecum twists in the axial plane, rotating clockwise orcounterclockwise around its long axis.At times caecum twists and inverts and occupy left upper quadrant. 72
    71. 71. PLAIN RADIOGRAPH• Plain film diagnostic in about 75%.• Dilated air filled caecum in an ectopic location, usually with the caecal apex in left upper quadrant• Kidney or coffee bean appearence due to medially placed ileo caecal valve producing a soft tissue indentation.• Little gas in distal colon, and usually collapsed.• Refluxed gas may erroneously suggest a small bowel obstruction. 73
    72. 72. Even though there isconsiderable distension ofthe caecum,one or twohaustral markings can beusually seen,unlike sigmoidvolvulusIdentification of attached gasfilled appendix confirmsdiagnosis. 74
    73. 73. SIGMOID VOLVULUS• Accounts for 60-70% of colonic volvulus• Classically occur in old age, psychiatrically disturbed, mentally retarded or institutionalised people.• Twists around mesenteric axis, rarely with axial torsion. 75
    74. 74. SIGMOID VOLVULUS-findings• Dilated loop of sigmoid colon that has a inverted U configuration with absent haustral margin is an important diagnostic point• Left flank overlap sign• Liver overlap sign• Apex under left hemidiaphram• Apex above 10th thoracic vertebra• Inferior convergence on left 76
    75. 75. 77
    76. 76. 78
    77. 77. COLONIC PSEUDO OBSTRUCTION• Also known as OGILVIE syndrome• Due to autonomic imbalance• Acute abd distension within10 days of precipitating pathology• Contrast enema/ CT required to exclude mechanical obstruction. 79
    78. 78. DISTINCTION BETWEEN SMALL AND LARGE BOWEL OBSTRUCTION Small bowel Large bowelValvulae Present in AbsentConniventes jejunumNumber of loops Many FewDistribution of Central PeripheralloopsHaustra Absent PresentDiameter 3-5 cm >5cmRadius of small largecurvatureSolid faeces Absent Present 80
    79. 79. Acute colitis• An assessment of the extent of colitis, state of mucosa,depth of ulceration,presence or absence of toxic megacolon and perforation can be made.• The extent of faecal residue related to the extent of colitis.• ‘Empty abdomen’-no faecal residue or gas s/o active total colitis• Intra luminal gas tend to accumulate as colitis progress. 81
    80. 80. Acute ulcerativecolitis- descendingcolon with irregularoutline, absenthaustrations, absentfaecal residue 82
    81. 81. TOXIC MEGACOLON• Fulminating form of colitis with trans mural inflammation.• Perforation and peritonitis common• Radiologically-dilatation and nodular mucosa.• Dilatation >55mm- significant and sufficient,• Changes most frequent in transverse colon.• Gaseous distension of small bowel- severe colitis – poor prognosis 83
    82. 82. TOXIC MEGACOLON• Plain abdominal radiograph shows distention of the transverse colon associated with mucosal edema.• The maximum transverse diameter of the transverse colon is 6 cm 84
    83. 83. • ISCHAEMIC COLITISo Disorder caused by vascular insufficiency and bleeding into the wall of the colono Preferentially involves the splenic flexure and the proximal descending colon.o Radiographically, difficult to identify unless some intra luminal gas present.o Submucosal thickening with cresentic margins (thumb- printing).o Involved area acts as a functional obstruction, so proximal parts frequently distended 85
    84. 84. Ischemic colitis 86
    85. 85. PSEUDOMEMBRANOUS COLITIS• Common cause of antibiotic associated diarrohea• Clostridium difficile is usually involved• 1/3 rd cases shows positive findings on plain films.• Colonic dilatation (32 %)• Thumb printing, thickened haustra, abnormal mucosa (18 %)• Untreated cases develops toxic megacolon and subsequent perforation.• Associated small bowel dilation(20 %), ascites(7 %) may be seen. 87
    86. 86. extensive haustral thickening(arrows) in a patient withpseudomembranous colitis 88
    88. 88. ACUTE APPENDICITISo Commonest acute surgical condition in the developing countryo Radiological signs- Appendix calculus(0.5-0.6)cm Right lower quadrant mass indenting the caecum Dilated caecum Sentinel loop Widening / blurring extraperitoneal fat line Scoliosis concave to the right Right lower quadrant haze Gas in the appendix 90
    89. 89. Appendicoliths are found in 10% of cases. Its presence withpain in rt lower abdomen is highly suggestive of diagnosis.91
    90. 90. ACUTE CHOLECYSTITIS• Gall stones- in 20% only• Porcelein GB• Right hypochondrial mass due to enlarged gall bladder.• Duodenal ileus• Ileus of hepatic flexure of colon• Gas within biliary system 92
    91. 91. 93
    92. 92. ACUTE PANCREATITIS• Acute pancreatitis refers to acute inflammation of the pancreas.• Causes • Gallstones (most common) • Alcohol abuse, usually chronic • Trauma, more often penetrating • Drug-induced • Anatomic abnormality • ERCP-induced • Infectious, especially post-viral in children • Vasculitis • Idiopathic 94
    93. 93. ACUTE PANCREATITIS• Pathological changes are edema, hemorrhege,lnfarction,fat necrosis followed by acute suppuration• Inflammatory processes tend into gastro colic ligament or paraduodenal areas- follow route of mesentry or extend out of peritoneum into perirenal space.• Lot of radiological signs described, but many are of little value in diagnosing individual cases. 95
    94. 94. Plain film changes- Chest x-ray-o Left sided pleural effusiono Splinting of left hemidiaphragmo Basal atelactasis Abdominal film-o Duodenal ileuso Gasless abdomeno “colon cut off” signo Renal “halo” signo Absent left psoas shadowo Indistinct mottled shadowingo Sentinel loopo Intrapancreatic gas-abscess/ enteric fistula 96
    95. 95. The abrupt termination of gas within the proximal colonat the level of the radiographic splenic flexure, usuallywith decompression of the distal colon 97
    96. 96. A sentinel loop is a focal area of adynamic ileus close to an intra-abdominal inflammatory process. The sentinel loop sign may aid in localizing the source of inflammation 98
    97. 97. • Later stages- pancreatic pseudocyst visible on plain film as large soft tissue mass• Pleural effusions, mainly left sided. 99
    98. 98. INTRA-ABDOMINAL ABSCESS• Abscesses are collections of pus that may displace adjacent structures following their involvement by inflammatory process• Usually of soft tissue density on plain films,but frequently contain gas.• Recognition of small gas bubbles outside bowel lumen,unchanged in position on sequential films, strongly s/o abscess. 100
    99. 99. SUBPHRENIC ABSCESS• Nearly always occurs as a result of surgery• Chest X-ray - raised hemidiaphragm - basal consolidation - pleural effusion Abdominal radiographs - gas/fluid level - Irregular gas pocket - Scoliosis towards the lesion - localised paralytic ileus Fluoroscopy- decrease diaphragmatic movement - locates small gas-fluid level/ irregular gas pockets 101
    100. 100. INTRA-ABDOMINAL ABSCESSSubhepatic abscess• A gas/fluid level is seen beneath the right hemidiaphragm. Note also the pleural effusion. The abscess developed in a 45-year- old woman following a cholecystectomy. 102
    101. 101. PARACOLIC ABSCESSLies close to the site of causative lesionDiverticulosis and appendicitis are thecommonest causative lesionsSoft tissue mass, often containing gasbubbles, and displacing colon – m.cradiographic presentation 103
    102. 102. INTRAMURAL GAS• Gas within walls of hollow viscus• Classification Cystic pneumatosis Interstitial emphysema Gas-forming infections 104
    103. 103. Cystic pneumatosis (Pneumatosis cystoides intestinalis)• Cyst like collections of gas in the walls of the hollow viscera• Left half of colon most frequently involved- pneumatosis coli• Plain abdominal radiographs- Gas containing cyst Pneumoperitoneum 105
    104. 104. INTERSTITIAL EMPHYSEMA• Linear gas, in single or double streaks, is found in the bowel wall• Common site- stomach & colon• Associated with toxic megacolon Emphysematous gastritis- - contracted stomach - mottled lucency in the left upper abdomen Emphysematous cholecystitis -occurs in absence of gallstones 106
    105. 105.  Necrotizing enterocolitis- in premature babies - generalised bowel distension - bowel wall thickening - pneumatosis - associated with gas in the portal vein Emphysematous cystitis- - linear gas streaks and gas cysts within the wall of the urinary bladder & within the lumen of the bladder 107
    106. 106. Linear or curvilinearlucencies are seen in thewalls of the bowel 108
    107. 107. Emphysematous gastritis Emphysematous cysytitis09 1
    108. 108. Emphysematous Cholecystitis 110
    109. 109. OTHER CONDITIONS 111
    110. 110. RENAL COLIC• A high proportion of patients with acute ureteric obstruction due to calculus present with an acute abdomen• About 90% of renal stones are radio-opaque. Uric acid stones especially may be missed• Plain abdominal radiograph- Calculi (90%) Meteorism Paralytic ileus Urinoma- soft tissue mass with loss of renal and psoas outines 112
    111. 111. 113
    112. 112. Emphysematous Pyelonephritis • Recognised by gas bubbles within the kidney or linear gas beneath the renal capsule • Occurs in uncontrolled Diabetes or Obstructive uropathy 114
    113. 113. ACUTE GYNAECOLOGICAL DISORDERS• Torsion of an ovarian cyst- pelvic mass• Dermoid cyst- contains calcification, teeth or fat• Ruptured ectopic pregnancy- - pelvic mass - paralytic ileus - free intrapeitoneal fluid 115
    114. 114. Ovarian teratomaPop corn like / cauliflower – uterine leiomyoma 116
    115. 115. Abdominal Aortic Aneurysm• Presents as acute abdomen with shock and simulated renal colic• Curvilinear calcification seen on AP radiograph but is best detected on a lateral view• Calcified walls of aorta can allow measurement of lumen• AAA if over 3 cm AP diameter• Ultrasound and CT are much more sensitive 117
    116. 116. 118
    117. 117. ASCITES• Only large amount of Ascites can be recognized on abdominal radiograph• Signs: 1.Obliteration of the inferior edge of the liver 2.Widening of the distance between the flank stripe and ascending colon. Normal is 2-3 mm 3. Fluid accumulation in the pelvis 4. centrally located bowel loops with bulging flanks 5. Ground glass appearnace_ requires large amount of fluid. 119
    118. 118. Supine view of the abdomen shows central displacement of the loops ofbowel,a uniform grayness to the abdomen, loss of any definition of theedge of the spleen or liver and displacement of the bowel loops out of 120the pelvis, all suggestive of ascites
    119. 119. Hydatid cyst in the Liver 121
    121. 121. • PAEDIATRICS 123
    124. 124. Conclusion• Following the history and clinical examination, plain film radiographs have been one of the first and most useful methods of further investigation.• Plain picture continues to be initial imaging modility in acute abdomen, particularly in perforation and intestinal obstruction.• In cases where definite diagnosis cannot be reached, further evaluation with USG and CT scan is required. 126
    125. 125. 127