Radionuclide imaging for GI system

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Radionuclide imaging for GI system

  1. 1. RADIONUCLIDE STUDIES OFTHE GASTROINTESTINAL SYSTEM Jiraporn Sriprapaporn, M.D. Nuclear Medicine, Radiology, Siriraj Hospital
  2. 2. GASTROINTESTINAL SYSTEM Eso transit timeEsophagus GE reflux (milk scan) Gastric emptying studyStomach: Ectopic gastric mucosa localizationIntestine GI bleeding study J SRIPRAPAPORN
  3. 3. GASTROINTESTINAL SYSTEMLiver-spleen Nonspecific SOL Tumor/infection HemangiomaBiliary system Hepatobiliary imaging J SRIPRAPAPORN
  4. 4. THE LIVER The biggest organ, 1500 g Anatomy: 4 parts- Right, Left, Caudate, and Quadrate lobes Histology: Hepatocytes or polygonal cells RE cells (Kupffer’s cells) Blood Supply: Portal vein 75 % Hepatic artery 25 % J SRIPRAPAPORN
  5. 5. FUNCTIONS OF LIVER Bile formation (Hepatocytes) Phagocytosis (RE cells) Protein synthesis, eg. albumin, fibrinogen Metabolizes substances J SRIPRAPAPORN
  6. 6. LIVER-SPLEEN SCAN(Routine Liver Scan)Tracer: 99mTc-sulfur colloid/ phytateRoute : IV injectionMechanism : Phagocytosis by RE cells (liver, spl, BM)Visualization : Liver and SpleenTechnique: Patient preparation : none Imaging : 15-20 min. Pi. : Static 6 views- Ant, Post, RL, LL, RAO, LAODiagnosis : Diffuse & focal lesions focal defect(s) -nonspecific (abscess, metastasis, cyst etc.) J SRIPRAPAPORN
  7. 7. Colloid Particles < 100 nm Bone marrow 200-1,000 nm Liver 1-5 um Spleen J SRIPRAPAPORN
  8. 8. Tc-99m Sulfur Colloid Size: 100-500 nm (1-5 um) Distribution of Uptake Liver: 80-85 % Spleen: 12 % Bone marrow: The rest J SRIPRAPAPORN
  9. 9. NORMAL LIVER SCAN Liver and spleen visualization Normal colloid distribution Uniform colloid distribution (no defect) J SRIPRAPAPORN
  10. 10. LIVER SCAN: Clinical ApplicationsEvaluate shape,size,positionSOL in the liver-spleen: Cold defect*: nonspecific (metasastases***) Hot lesionDiffuse hepatocellular disease : COLLOIDSHIFT (Decreased hepatic, increased splenic& BM uptake) Ex. Cirrhosis J SRIPRAPAPORN
  11. 11. COLLOID SHIFTPathophysiology Change in blood flow Hepatocellular impairment Stimulation of RE systemFindings Decreased hepatic uptake Increased splenic & BM uptakeEx. Cirrhosis J SRIPRAPAPORN
  12. 12. LIVER SCAN ROUTINE LIVER SCAN : Tc-99m sulfur colloid (SC) or Tc-99m phytate LIVER SCAN with other R’pharmaceuticals Tc-99m RBC for Hepatic Hemangioma Tc-99m HMPAO-WBC for infection img. Ga-67 scan for tumor/infection imaging Tl-201, Tc-99m MIBI for tumor imaging J SRIPRAPAPORN
  13. 13. Hepatic Blood Pool Scan (99mTc-RBC) Aim : To Dx hepatic hemangioma Sensitivity: SPECT almost 100% for > 1.5 cm lesions Technique : Flow: normal or decreased Static images: may be cold initially Delayed images *** hot lesions Positive : Increased activity in the lesion with time J SRIPRAPAPORN
  14. 14. HEPATIC HEMANGIOMA SPECTVascular Study 3-D image J SRIPRAPAPORN
  15. 15. HEPATIC HEMANGIOMA Planar RBC SPECTU/S Tc-99m RBC Scan J SRIPRAPAPORN
  16. 16. LIVER SCAN U/SSimple RapidNot operator-dependent Operator-dependentMinimally invasive Absolutely noninvasiveNot expensive Not expensiveLess sensitive More sensitiveLess specific More specificNature: nonspecific Nature: Cystic vs solidDiffuse & focal dis. Focal > diffuseMinimal radiation No radiationAnatomy: intrahepatic Anatomy: intra-extrahep. J SRIPRAPAPORN
  17. 17. CT SCAN MRIMore expensive Most expensiveMore radiation No radiationGood anatomic Excellent anatomicdetails details Intrahepatic Intrahepatic Extrahepatic ExtrahepaticMor available Less available J SRIPRAPAPORN
  18. 18. CONCLUSION: LIVER SCAN Liver metastases** Role of radionuclide study Role of U/S , CT, MR Tc-99m RBC for hemangioma ! SPECT/CT will enhance sensitivity & specificity of the test. J SRIPRAPAPORN
  19. 19. SLLEEN SCAN Radiopharmaceuticals: Tc-99m sulfur colloid, Tc-99m phytate: phagocytosis by RE cells Tc-99m heat-denatured red cell: cell sequestration (specific for splenic function) Indication: Accessory spleen, splenic infarct J SRIPRAPAPORN
  20. 20. A 56-year-old woman who underwent splenectomy two yearsago for idiopathic thrombocytopenic purpura (ITP) continuesto have thrombocytopenia Planar and SPECT images of the abdomen ( Tc-99m in vitro- labeled heat-damaged red blood cells) Two foci of increased activity are seen in the posterior aspect of the left upper quadrant consistent with residual splenic tissue. http://nucmed.richis.org/case/Infec/MIRsi0201.htm J SRIPRAPAPORN
  21. 21. HEPATOBILIARY IMAGING
  22. 22. Radiopharmaceuticals forHepatobiliary ImagingTc-99m Iminodiacetic acid) IDA derivatives Tc-99m diisopropyl IDA (DISIDA or Disofenin) Tc-99m trimethylbromo IDA (Mebrofenin) J SRIPRAPAPORN
  23. 23. HEPATOBILIARY SCANTracers : Tc-99m IDA derivatives (Tc-99m DISIDA,Mebrofenin)Route : IV injectionMechnism : Carrier-mediated, non sodium dependentorganic anion transport processTecnique : -Fasting 4-6 hr -Dynamic study for at least 1 hour +/- delayed imagingVisualization : Liver and biliary system includinggallbladder until excretion into small bowel (Normalwithin 1 hour) J SRIPRAPAPORN
  24. 24. HEPATOBILIARY SCAN:IndicationsGallgladder disease Acute cholecystitis*Biliary tract obstruction DDx biliary atresia vs neonatal hepatitisBiliary leakage J SRIPRAPAPORN
  25. 25. NORMAL HEPATOBILIARY SCANVisualization :Liver and biliary system including Right & left hepatic ducts Common hepatic duct Common bile duct Gallbladder Until excreted into small bowelWithin 1 hour J SRIPRAPAPORN
  26. 26. NORMAL HEPATOBILIARY SCAN Tc-99m DISIDA J SRIPRAPAPORN J SRIPRAPAPORN
  27. 27. NONVISUALIZED GALLBLADDER Acute cholecystitis Severe chronic cholecystitis Prolonged fasting Intercurrent severe illness Acute pancreatitis Severe liver disease J SRIPRAPAPORN
  28. 28. BILIARY ATRESIA Early images 24-hr image J SRIPRAPAPORN
  29. 29. NEONATAL HEPATITIS 1 hr 4 hr J SRIPRAPAPORN J SRIPRAPAPORN
  30. 30. GI BLEEDING STUDY Lower GI tract Active bleeding Tc-99m SC or Tc-99m RBC* (intermittent) More sensitive than angiography but less anatomical details Less specific in nature J SRIPRAPAPORN
  31. 31. GI BLEEDING STUDY: TECHNIQUE Preparation: NPO Position: Supine Region: Anterior- lower abdomen Imaging: Flow 1 min Dynamic imaging for 1-2 hr with additional delayed images as required. J SRIPRAPAPORN
  32. 32. POSITIVE FINDINGS •Tc-99m RBC •Hepatic flexureExtravasation of the tracer into bowel lumen Focal area of increased activity, move // bowelmovementPattern depends on site of bleeding & bowelperistalsis J SRIPRAPAPORN
  33. 33. Tc-99m RBC Tc-99m SCBleeding 500+ ml/ 24 T1/2 in bl pool 2.5-3 minhr. Bleeding rate 0.05-0.1Bleeding rate 0.1-0.5 ml/min*ml/min Intetrmittent bleedingIntermittent bleeding- requires reinjection24h F/U wo reinjection Higher T/B ratio (lowerLower T/B ratio (higher Bcg)Bcg) Upper abd interfered byUpper & lower GI liver-spleen activitybleeding J SRIPRAPAPORN
  34. 34. Meckel’s Scan Meckel’s diverticulum represents a persistence of the omphalomesenteric (vitelline) duct at its junction with the ileum. Meckel’s diverticulum is the most common cause of lower GI bleeding in small children. Meckels are disease of “2” Most of the patients are asymptomatic (80%). Gastric mucosa is most commonly found mucosal lining in the Meckel’s. Most common Sx is painless blood per rectum- gastric mucosa was found in 95% of bleeding lesions. J SRIPRAPAPORN
  35. 35. No need for active bleeding during the scanMeckel’s Scan Indication: bleeding per rectum in small children Radiopharm: Tc-99m pertechnetate, IV Mechanism: Localization of ectopic gastric mucosa Imaging: Patient preparation: NPO 4 hr Sequential abdominal imaging for 1-2 hr. Positive findings: Focal hot spot (RLQ) // stomach activity Sen 85%, spec 95% J SRIPRAPAPORN
  36. 36. Meckel’s Diverticulum Stomach Stomach M Bladder U. Bladder J SRIPRAPAPORN
  37. 37. GASTROESOPHAGEAL STUDY1. Esophageal transit study : dysphagia2. Gastroesophageal reflux study (milk scan): GE reflux3. Gastric emptying study : dyspepsia J SRIPRAPAPORN
  38. 38. DISEASES OF THE ESOPHAGUS Motility disorders of the esophagus: scleroderma, achalasia Gastroesophageal reflux & related disorders Structural lesions of the esophagus: tumors, rings, webs J SRIPRAPAPORN
  39. 39. GASTROESOPHAGEAL STUDY1. Esophageal transit study2. Gastroesophageal reflux study (milk scan)3. Gastric emptying study J SRIPRAPAPORN
  40. 40. ESOPHAGEAL TRANSIT STUDY Indications: swallowing difficulty eg. dysphagia, heartburn Radiopharm: Tc-99m SC - neither absorbed nor secreted by esophageal mucosa, 150-500 uCi Technique: 4-6 hr fasting Liquid*: Water = most common, 10 ml bolus Position: Upright* ( more physiological & is preferable or supine ( no effect of gravity) Acquisition: Dynamic imaging 0.8 s x 240 s J SRIPRAPAPORN
  41. 41. ESOPHAGEAL TRANSIT STUDY Quantification: 3 regions Time-activity curvesInterpretation: At 15 sec post bolus swallowing, >90% of radioactivity passed into the stomach J SRIPRAPAPORN
  42. 42. GASTROESOPHAGEAL STUDY1. Esophageal transit study2. Gastroesophageal reflux study (milk scan)3. Gastric emptying study J SRIPRAPAPORN
  43. 43. GE REFLUX STUDY (MILK SCAN)Indication: To detect GE reflux:- regurgitation ofgastric contents esophagusTracers : Tc-99m phytate, Tc-99m SC 300 uCiTechnique : NPO, oral tracer adm. Within 30 s Supine imaging over EG junction Dynamic for >10-20min. Views: anterior ( & posterior)Positive : Activity from the stomach esophagus N < 3 %, Abn >4 % J SRIPRAPAPORN
  44. 44. GE REFLUX STUDY (MILK SCAN) J SRIPRAPAPORN
  45. 45. GASTROESOPHAGEAL STUDY1. Esophageal transit study2. Gastroesophageal reflux study (milk scan)3. Gastric emptying study J SRIPRAPAPORN
  46. 46. THE STOMACHAnatomy Fundus: reservoir Body: grinder Antrum : propeller, grinder Pylorus: particles < 1 mm passPhysiology: Vagus N, ANS J SRIPRAPAPORN
  47. 47. Rate of gastric emptyingTypes & compositions of food: Physical state: Liq-exponential, solid-linear Particle size Caloric contents: Fat delays GE0 Fiber contents Liquid Caloric density Acididy & viscosityVolume of foodNeuro regulartory factors Solid J SRIPRAPAPORN
  48. 48. Rate of gastric emptying Sex Age Obesity Concomitantdiseases eg. DM Position J SRIPRAPAPORN
  49. 49. GASTRIC EMPTYING STUDYClinical indications: Dyspepsia, dumping syndromeTracers : Solid: Tc-99m phytate, Tc-99m SC 1 mCi, Oral Liquid: In-111 Cl 100 uCi CG =[CA . Cp ]1/2Technique : C = Counts calculated G NPO, upright, eat within 10 min by geometric mean Dynamic imaging for 120min. C = Counts in anterior A view Views: anterior & posterior C = Counts in p (geometric means) or LAO posterior view J SRIPRAPAPORN
  50. 50. GASTRIC EMPTYING STUDY J SRIPRAPAPORN J SRIPRAPAPORN
  51. 51. INTERPRETATION OF GET Half-emptying time (T1/2)= 50 % emptying Normal T1/2 (min)Phase Males FemalesSolid 77 + 32 92 + 7.5Liquid 38 + 26 53.8 + 4.9 J SRIPRAPAPORN
  52. 52. NORMAL SOLID-LIQUIDGASTRIC EMPTYING STUDY LIQUID SOLID Lag phase J SRIPRAPAPORN
  53. 53. GEOMETRIC MEANATTENUATION CORRECTIONCGM= [CANT . CPOST]1/2 J SRIPRAPAPORN
  54. 54. DUAL-PHASE SOLID-LIQ GASTRICEMPTYING STUDY A: Normal subject, N solid & liq emptying B: DM, N solid & liq emptying C: DM, delayed solid, N liq emptying D: DM, delayed both solid & liq emptying J SRIPRAPAPORN
  55. 55. DIABETIC GASTROPARESIS A: Baseline study B: 2 wk after metoclopramide Rx C: 1 wk after cisapride Rx J SRIPRAPAPORN
  56. 56. SUMMARYEsophagus: Milk scanStomach: Gastric emptyingstudyIntestine: GI bleedingLiver-spleen: Tc-99m SC orphytate, RBCBiliary system: Hepatobiliary J SRIPRAPAPORN

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