Gastrointestinal Radiology

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Gastrointestinal Radiology

  1. 1. GASTROINTESTINAL RADIOLOGYGASTROINTESTINAL RADIOLOGY  1. Liver Lesions – Haemangioma and HCC1. Liver Lesions – Haemangioma and HCC  2. CT Colonography2. CT Colonography  3. Small bowel - CT, MRI or fluoroscopy?3. Small bowel - CT, MRI or fluoroscopy?  4. Rectal tumor – MRI staging4. Rectal tumor – MRI staging  5. Anal fistula – MRI imaging5. Anal fistula – MRI imaging Topics to be covered
  2. 2. Liver – Haemangioma (US)Liver – Haemangioma (US) Atypical
  3. 3. Liver Haemangioma CTLiver Haemangioma CT A) Pre-contrastA) Pre-contrast
  4. 4. B) Arterial phaseB) Arterial phase
  5. 5. C) Portal venous phaseC) Portal venous phase
  6. 6. D) Delayed phaseD) Delayed phase CT – we will not do delayed phase unless haemangioma suspected. Please specify “? haemangioma” on request form.
  7. 7. Haemangioma SummaryHaemangioma Summary  Common- often incidentalCommon- often incidental  US – Echogenic -no halo. No colour flow.US – Echogenic -no halo. No colour flow. Aytpical – hypo-echoic in fatty liverAytpical – hypo-echoic in fatty liver - mixed echotexture- mixed echotexture  CT – C- low densityCT – C- low density C+ peripheral vessels (uneven)C+ peripheral vessels (uneven) C+ PV /delay progressive fill-inC+ PV /delay progressive fill-in Small haemangioma fill in immediately andSmall haemangioma fill in immediately and cannot be distinguished from metastates.cannot be distinguished from metastates.  MRI features similar to CT post GadoliniumMRI features similar to CT post Gadolinium
  8. 8. CT -HCCCT -HCC pre contrastpre contrast
  9. 9. Arterial enhancementArterial enhancement (central and early)(central and early)
  10. 10. Washout on portal venousWashout on portal venous indicates fast flowindicates fast flow
  11. 11. HCC SummaryHCC Summary  US - usually heterogeneous Usually HepB +ve withUS - usually heterogeneous Usually HepB +ve with raised alpha FPraised alpha FP  CT – C- low densityCT – C- low density C+A – central early contrast (high flow rate)C+A – central early contrast (high flow rate) C+PV – washout cf with liverC+PV – washout cf with liver –– may have a capsulemay have a capsule  MR – intracellular fat on T1 out of phaseMR – intracellular fat on T1 out of phase - similar perfusion characteristics to CT- similar perfusion characteristics to CT
  12. 12. MRI IMAGES of LIVERMRI IMAGES of LIVER  Look at CSF first to tell if T1 or T2Look at CSF first to tell if T1 or T2  T1-in/out.T1-in/out.  T1 are grey. Fluid is dark. Black outlineT1 are grey. Fluid is dark. Black outline  T2-incl HASTE.T2-incl HASTE.  More definition. Fluid is bright.More definition. Fluid is bright.  Gadolinium – always with T1Gadolinium – always with T1
  13. 13. Fatty liver with sparingFatty liver with sparing
  14. 14. Same pt - out of phase T1 MRISame pt - out of phase T1 MRI
  15. 15. Same patient - CT non-contrastSame patient - CT non-contrast
  16. 16. CT COLONOGRAPHYCT COLONOGRAPHY Dissection Strip, anus to caecum Endoluminal (for fun only) 800/40 window Axial to loops Orientation Overview
  17. 17. Advantages / disadvantagesAdvantages / disadvantages  Sensitivity and specificity is of the order of 90 %Sensitivity and specificity is of the order of 90 % for 10 mm polyps.for 10 mm polyps.  Easy, quick and well tolerated.Easy, quick and well tolerated.  Beats barium enema hands down.Beats barium enema hands down.  Safer than optical colonoscopySafer than optical colonoscopy  Approx. half the price of optical colonoscopyApprox. half the price of optical colonoscopy  No intervention possible as in optical CyNo intervention possible as in optical Cy  At present for “Ba enema” indications, but is likelyAt present for “Ba enema” indications, but is likely to be used for screening in future.to be used for screening in future.  Radiology manpower training required.Radiology manpower training required.  Radiation dose equivalent to Ba EnemaRadiation dose equivalent to Ba Enema
  18. 18. Incidence of Colonic Perforation at CT Colonography: Review of Existing Data and Implications for Screening Asymptomatic Adult Source: InternationalWorking Group on Virtual Colonoscopy Total VC studies considered 21,923 Symptomatic Perforation Rates for VC* 0.005% Total Perforation Rates for VC 0.009% Perforation Rates for Conventional Colonoscopy 0.1-0.2% Pickhardt2007
  19. 19. CTC vs Optical ColonoscopyCTC vs Optical Colonoscopy  CTC for average risk and Fam Hx pts.CTC for average risk and Fam Hx pts.  > 50 yrs (radiation)> 50 yrs (radiation)  Contraindicated if inflammatory bowel or on steroidsContraindicated if inflammatory bowel or on steroids (risk of perforation as inflation is done “blind” as(risk of perforation as inflation is done “blind” as opposed to Ba enema).opposed to Ba enema).  Optical Colonoscopy – if biopsy or polypectomy probOptical Colonoscopy – if biopsy or polypectomy prob neededneeded  All polyposis syndromesAll polyposis syndromes  High riskHigh risk  Inflammatory Bowel DiseaseInflammatory Bowel Disease Consider “Is intervention likely to be needed?” – (cf MRCP vs ERCP)
  20. 20. Overview of CT colonography?Overview of CT colonography?  ProcessProcess CurrentlyCurrently FutureFuture  CLEANSECLEANSE -Tagging-Tagging -Subtraction-Subtraction  DISTENDDISTEND -Air-Air -CO2-CO2  COMPUTECOMPUTE -Workstation-Workstation -new programs-new programs  VIEWVIEW -Time-Time - CAD- CAD  REPORTREPORT -Issues-Issues
  21. 21. Prep and taggingPrep and tagging Slide courtesy Dr Helen MooreSlide courtesy Dr Helen Moore
  22. 22. Longer tube and patient can apply airLonger tube and patient can apply air themselvesthemselves Slide courtesy Dr Helen MooreSlide courtesy Dr Helen Moore
  23. 23. Lateral topogramLateral topogram
  24. 24. Philips workstation layoutPhilips workstation layout
  25. 25. Incomplete air column -Excess fluidIncomplete air column -Excess fluid SupineSupine ProneProne
  26. 26. Diverticular diseaseDiverticular disease
  27. 27. 4 mm Polyp4 mm Polyp
  28. 28. Ileo-caecal valveIleo-caecal valve Residual tagging Arrow points To caecum Caecal pole
  29. 29. Dirty Caecum-Dirty Caecum- not fully open on supine or prone viewsnot fully open on supine or prone views 54 yr54 yr RecommRecomm opticaloptical colonoscopycolonoscopy
  30. 30. The dirty caecumThe dirty caecum
  31. 31. Complex Folds at flexuresComplex Folds at flexures
  32. 32. RadiationRadiation  Barium enema 6 – 8 mSvBarium enema 6 – 8 mSv  CTC estimate of 7.6 mSv with low mAs.CTC estimate of 7.6 mSv with low mAs. Increased noise, but high resolutionIncreased noise, but high resolution improves definition of small polypsimproves definition of small polyps  Thin slice, limit tube currentThin slice, limit tube current  Background radiation is 2.4 MSv/yearBackground radiation is 2.4 MSv/year The worldwide average background dose for a human being is about 2.4 milli sievert (mSv) per year.[1] This exposure is mostly from cosmic radiation and natural isotopes in the Earth. This is far greater than human-caused background radiation exposure, which in the year 2000 amounted to an average of about 0.01 mSv per year from historical nuclear weapons testing, nuclear power accidents and nuclear industry operation combined,[2] and is greater than the average exposure from medical tests, which ranges from 0.04 to 1 mSv per year. Source Wikipedia.
  33. 33. Small Bowel ImagingSmall Bowel Imaging  < 35 yrs – MRI for radiation reasons< 35 yrs – MRI for radiation reasons  However if pre-surgical workup–fluoroscopyHowever if pre-surgical workup–fluoroscopy  CT Enteroclysis – only difference from CT isCT Enteroclysis – only difference from CT is negative contrast in bowel. No advantage tonegative contrast in bowel. No advantage to do if recent normal CT.do if recent normal CT.  MR Small bowel – breath-hold sequences,MR Small bowel – breath-hold sequences, dynamic change between sequences. Gooddynamic change between sequences. Good soft tissue differentiation. +/- Gadoliniumsoft tissue differentiation. +/- Gadolinium
  34. 34. Normal Fluoroscopic EnteroclysisNormal Fluoroscopic Enteroclysis Jejunal intubation Low density barium Pumped in to distend Intubation 10 min Study 20 min
  35. 35. Terminal ileumTerminal ileum
  36. 36. Skip lesions - ProximalSkip lesions - Proximal
  37. 37. Follow-throughFollow-through time-consumingtime-consuming flocculationflocculation Strictures mayStrictures may be hiddenbe hidden Is supersededIs superseded by other testsby other tests
  38. 38. Enteroclysis- same patientEnteroclysis- same patient
  39. 39. Intra-luminal massIntra-luminal mass
  40. 40. CT EnteroclysisCT Enteroclysis Tumor shows up against negative contrast in bowel. Positive contrast could hide it Histo- GIST
  41. 41. CT ENTEROCLYSISCT ENTEROCLYSIS Volumen oral contrast for 45 min pre scanVolumen oral contrast for 45 min pre scan IV MaxolonIV Maxolon IV contrast on tableIV contrast on table CT to include anal canal and with sagittal.CT to include anal canal and with sagittal.
  42. 42. CT ENTEROCLYSISCT ENTEROCLYSIS Jejunum often thick-walled Can evaluate bowel wall due to negative contrast in lumen and IV contrast in wall. Evaluates stomach well also Plus standard CT Reserved for older patients due to radiation dose
  43. 43. MRI Small BowelMRI Small Bowel  Oral Volumen 30 – 45 min prior (or Ioscan)Oral Volumen 30 – 45 min prior (or Ioscan)  +/- IM Buscopan for peristaltic movement+/- IM Buscopan for peristaltic movement  Good for Crohns patients with multiple studiesGood for Crohns patients with multiple studies and large radiation dose over time.and large radiation dose over time.  Coronal TRUFICoronal TRUFI  Coronal TRUFI fat saturationCoronal TRUFI fat saturation  Coronal HASTECoronal HASTE  Axial HASTEAxial HASTE  Coronal T1Coronal T1
  44. 44. MRIMRI ENTEROCLYSISENTEROCLYSIS TRUFITRUFI
  45. 45. Normal- HASTE sequenceNormal- HASTE sequence
  46. 46. Terminal ileumTerminal ileum
  47. 47. Cutaneous fistulaCutaneous fistula Post Gadolinium T1 fat sat
  48. 48. Caecum / TICaecum / TI
  49. 49. Crohns diseaseCrohns disease
  50. 50. NormalNormal FAT SATURATION
  51. 51. Sag, axial and coronalSag, axial and coronal
  52. 52. Normal anal canal - sagittalNormal anal canal - sagittal Subcutaneous External sphincter Puborectalis Internal sphincter
  53. 53. Normal anal canal - axial at PRNormal anal canal - axial at PR mucosa Internal sphincter Fat in inter- sphincteric space Pubo-rectalis = upper external sphincter
  54. 54. Normal anal canal - coronalNormal anal canal - coronal Internal Sphincter Puborectalis External Sphincter
  55. 55. Post Gad fat saturation T1Post Gad fat saturation T1 Drain in situDrain in situ ANTERIOR POSTERIOR
  56. 56. UC - mucinous tumourUC - mucinous tumour
  57. 57. UC - mucinous tumourUC - mucinous tumour
  58. 58. Anal canal tumourAnal canal tumour

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