Small bowel imaging small bowel AIIMS .ppt

Presentation on small bowel imaging

1. SMALL BOWEL
IMAGING
Candidate:Shivani Pahwa
Moderator: Dr Sanjay Thulkar

2. Imaging Modalities
•X rays
•Barium studies
•CT
•MRI
•Angiography
•PET
•Sonography

3. Plain radiographs
Initial investigation in casualty

4. Suspected
perforation

5. Obstruction

6. Barium Studies
Indirect
•Small bowel follow
through
•Small bowel meal
•Peroral
pneumocolon
•Reflux examination
Direct
•Enteroclysis(small
bowel enema)

7. BMFT
•Two types
Conventional (radiographic)
Fluoroscopic
•Preparation
Dulcolax-afternoon before study
Abstain from food and drink in the
morning
Metoclopramide

8. BMFT
C/I of Metoclopramide
High grade obstruction
H/O allergy
Reduces lumen diameter
?disadvantage

9. BMFT
•Barium suspension-40%-50% w/v
•Limitations
Underdistention spurious nodularity
Low grade obstrn
Early mural infiltrn MISSED

10. BMFT
•Fluoroscopic FT after double contrast
UGI examn-AVOID
•Double contrast follow through
•Peroral pneumocolon
•Retrograde small bowel enema
•See through small bowel study

11. Small bowel follow through
Jejunum ileum
Thickness of
folds
2-3 mm 1-2 mm
Diameter of
lumen
Upto3 cm Upto2 cm

12. Enteroclysis
•Single contrast
-28-42% Ba @ 75ml/min
•Biphasic enteroclysis
-Methylcellulose ,air
-Maglinte method-50% w/v Ba
-Harlinger method-80% w/v Ba

13. Advantages of enteroclysis
•Pylorus bypassed
•Tests luminal distensibility
•Induces hypotonia
simultaneous display of all dilated loops
•Completed in 20-30 min

14. Enteroclysis
•Disadvantages
-Discomfort of intubation
-technical problems
High flow rate
poor distension
reflux into stomach & duodenum
Low flow rate
hypotonia,retardedprogress

15. Enteroclysis
Jejunum Ileum
Folds per inch
length
4-7 2-4
Thickness of folds1-2 mm 1-1.5 mm
Diameter of lumen Upto4 cmUpto3 cm
Wall thickness 1-1.5 mm 1-1.5 mm

16. CT Enteroclysis
Kloppel and colleagues (1992)
•Barium studies mucosal details
• CT extraluminal abnormalities
•CT Enteroclysis both

17. CT Enteroclysis
Contrast agents
Neutral
•0.5% methylcellulose
•Water
•Low density
Barium(VoLumen)
•Polyethylene glycol
Positive
•4 –15% water
soluble contrast
•Dilute 6% Barium

18. CT Enteroclysis-Neutral contrast

19. CT Enteroclysis
Indications for neutral contrast
No e/o obstruction on plain radiographs
Unexplained GI bleed or anemia
Staging of known Crohn’s disease
Unexplained pain abdomen
Alternate examination before/after capsule
endoscopy

20. CT Enteroclysis -Positive contrast

21. CT enteroclysis
Indications for positive contrast
C/I to IV contrast
Suspected recurrent small bowel obstruction
inconclusive conventional studies
Suspected small bowel disease
inconclusive conventional studies
Suspected obstruction
H/O surgery
H/O radiotherapy

22. CT Enteroclysis
Fluoroscopic Phase
Small balloon catheter (9 F Maglinte
Minicatheter)-positioned distal to DJ
flexure
0.3 mg glucagon IV
Infuse 1.5L of water at 100 ml/min
RCNA 2007

23. CT Enteroclysis
CT phase
0.3 mg glucagon IV
1.5 L contrast @ 100 ml/min
IV contrast 4ml/sec,150 ml
Acquisition at 50 sec delay
RCNA 2007

24. CT Parameters
40 channel CT
Source :40 x 0.625 mm
Reformat:2.0 mm @ 1.0 mm recon interval
Neutral contrast
window width = 360 HU
window level = 40HU
Positive contrast
window width = 1200HU
window level =200 HU

25. CT Enterography
•Patient Preparation
•Oral contrast 0.1% w/v Ba solution with
sorbitol
•Volume-900 to 1800 ml over 30 min to 1hr
•metoclopramide +/-
•1 mg glucagon (i/m,i/v)

26. CT Enterography-Scanning
Techniques
•Single phase imaging
-”Enteric phase” -45 sec
-espfor Crohn’sDs & obstn
•Multiphasicimaging
for Obscure GI bleed
1.Arterial phase-6 sec
2.Enteric phase-20-25 sec
3.Delayed phase-70-75 sec

27. MR Imaging
Specific advantages
Better evaluation of fistulas
Evaluation of bowel distensibility
multiphasic imaging
MR fluoroscopy

28. Enteric Contrast Agents
•Negative
•Positive
•Biphasic

29. Negative Contrast Agents
•Super paramagnetic particles
•Perfluorooctyl bromide
•Ferumoxide oral suspension
•Oral magnetic particles
•Low signal intensity on T1 w and T2w

30. Advantages
•Bowel wall thickening -T1w
•Bowel wall enhancement
•Inflammation in surrounding fat-T2w
•Inter loop abscesses –more conspicuous

31. Pitfalls
GI side effects-5-15%
Imaging artefacts
Cost
Paradoxical High intensity if not
homogenously distributed

32. Positive Contrast Agents
Paramagnetic substances-
•Gadolinium chelates
•Manganese ions
•Ferrous ions
•Natural substances-milk,oil,ice cream,green
tea,blueberry juice

33. Pearls and pitfalls
Demonstrate wall thickness well on T1w
Inter loop abscesses shown well on T1w
-abscess has low signal intensity on T1
High signal intensity in lumen-masks bowel
wall enhancement or intraluminal masses after
I/V contrast

34. Biphasic Contrast Agents
•T1w –low signal intensity
T2w-high signal intensity
•Agents in use-
-water
-polyethylene glycol
-low Hounsfield Barium

35. Technical issues
•Enteroclysis vs enterography
•Pulse sequences
T2 w
single shot HASTE
True-FISP,
balanced fast field echo
T1 w contrast enhanced gradient echo
sequences with fat supression-2D or 3D

36. MR Enteroclysis

37. Angiography
•To detect Obscure GI bleed,massive acute
bleed
•Selective catheterisaation of coeliac
axis,SMA,IMA

38. Radionucleide studies
•Acute lower GI bleed
-Technetium 99 sulphur
colloid
-technetium 99 labelled
RBC’s-better
•Meckel’sdiverticulum
-Technetium 99 pertechnate
•Inflammatory bowel disease
-Indium 111 labelledWBC’s

39. Small bowel pathology
Inflammatory
Neoplastic
miscallaneous

40. Tuberculosis
Barium studies
First stage
-accelerated transit
-chicken intestine
-precipitation of barium
-crenated,spiculated contour
-thick folds

41. Tuberculosis
Second stage
•Ulcerations +
Third stage
•absent mucosal relief
•Short ‘hour glass’
stenosis
•Multiple strictures
•Fixed, matted loops
•Signs of malabsorption

42. IC tuberculosis
•Fleischner/inverted
umbrella sign
•Napkin ring stenosis
•Goose neck
deformity
•Purse string stenosis
•Stierlin’s sign
•String sign

43. USG
•Extramucosal changes
•Thickened bowel wall
>5 mm -non-distended
>3mm -distended
•Pseudo-kidney
•Club sign

44. Tuberculosis
CT
Mural thickening of IC area-
concentric
Low density areas in bowel
wall
Skip areas
Enlarged mesenteric lymph
nodes
-with central low attenuation
areas
Obstruction
D/D-Crohn’s

45. Crohn’s Disease
•Small bowel involved in 80%
•Diagnosisand evaluation of early disease
-Barium studies
-Colonoscopy
•Advanced disease
-CT
-MRI

46. Crohn’s Disease
Early disease
•Smooth symmetrical thickening of mucosal
folds
•Coarse villous pattern
•Aphthoid ulcers 1-3mm
Twoor more signs +
Increased likelihood of Crohn’s

47. Crohn’s disease
Intermediate disease
•Obliteration,distortio
nof mucosal folds
•Stellate/rosethorn
appearance
•Linear ulcers
,retraction of
mesenteric border
•sacculationof
redundant border

48. Crohn’s Disease
Advanced disease
•Deep linear
ulcers/fissures
•Pseudopolyps
•Cobblestone /
ulceronodular
appearance
•Anti mesenteric
redundancy-
disappears
•Fat wrapping

49. Crohn’s disease-CT

50. Crohn’s Disease

51. Crohn’s Disease-MR

52. Neoplasms-malignant

53. Adenocarcinoma
•40% of malignant small bowel tumors
•Duodenum/proximal jejunum
•Barium-narrowing

54. Adenocarcinoma
Eccentric focal mass
Asymmetric
thickening
metastasis
lymph nodes
mesentry

55. Lymphoma-NHL
Barium
Aneurysmal
Constrictive
Nodular
Ulcerative
Mesenteric
Sprue
endoexoenteric

56. Lymphoma –Non-Hodgkin’s
CT
Circumferential
Cavitary
Mesenteric
Value in treatment
planning & post-
therapy follow up

57. Lymphoma-Hodgkin’s
•Extremely rare
•Barium
-tapered,eccenteric narrowing
-displacement of bowel loops by nodal mass

58. Leiomyosarcoma

59. Leiomyosarcoma
Ileum (50%) jejunum
(33%)
Barium
Separation of loops
Ulceration, barium
filled cavities
Tethering
Shape altered by
compression

60. Leiomyosarcoma
CT
Bulky , eccenteric
lesion
Calcification +/-
Significant
enhancement with IV
contrast
Metastasis to
liver,omentum

61. Carcinoid
•Appendix ,terminal
ileum
Barium
Less than 2 cm-
incidental submucosal
nodule
Mesenteric
involvement-
-crowding of folds
-kinking of bowel wall
-separation of loops
-narrowing of lumen

62. Carcinoid
CT
desmoplasticrxn
Mesenteric mass
with curvilinear
strands extending to
bowel loops-stellate
appearance
Adenopathy
Liver metastasis
Calcification-50%

63. Somatostatin receptor scanning-Indium
111 pentetreotide

64. Metastasis
Intraperitoneal
Bowel
Ovary
Uterus
Hematogenous
Malignant melanoma-Bull’s eye/ target
Bronchogenicca
Breast ca
Local

65. Neoplasms -benign
Adenoma
Leiomyoma
Lipoma
Haemangioma

66. Imaging in Small Bowel Obstruction
20% of patients presenting with acute
abdomen
1
st
investigation-plain radiographs

67. Enteroclysis –Method of choice
Low grade/intermittent obstruction
Unsuspected closed loop obstruction
H/O laparotomy for malignancy
Radiation enteropathy
Strictures in Crohn’s ds

68. Enteroclysis –C/I
Acute & complete or high grade obstruction
Suspicion of strangulated obstruction
Suspected perforation

69. CT
Level of obstruction
Cause
Method of choice in-
Acute,complete obstruction
Adynamic ileus
Prolonged high grade obstruction
Suspicion of strangulation
Suspicion of inflammatory process

70. Obstruction
Beak sign
Whirl sign

71. Obstruction
Strangul ation
Closed loop
obstruction

72. Obstruction
Adhesions
Hernias

73. Obstruction-intussuception

74. Obstruction
Radiationenteropathy

75. Obstruction
Malignancy
Metastasis

76. Obstruction
Inflammatory
Gall stone ileus

77. Mesenteric Ischemia
•Rapid radiographic evolution
•Plain X rays
-thickened valvulae conniventes
-dilated gas filled bowel loops
-thickening of bowel wall
-thumbprinting-occassionally
-air in intestinal wall/hepatic veins

78. Mesenteric Ischemia
conventional

79. Mesenteric Ischemia-CT
•Neutral oral & IV contrast
•Arterial phase
•Venous phase

80. Mesenteric ischemia-CT
Thin Axial images-
-proximal arterial patency
Sagittalprojection
-to evaluate origin & proximal portion of
mesenteric arteries
-to identify anatomic variants
Volume rendering-coronal/coroblique
-distal branches
MIP
-smallest branches

81. Mesenteric Ischemia
Findings
Bowel dilatation
Mesnteric edema
Vascular changes

82. Mesenteric Ischemia
Bowel dilatation
Bowel thickening
>8mm
transmuralinfarct -
paper thin
Bowel wall attenuation
low density edema
high density hge

Pneumatosis/portomese
ntericvenous gas

83. Mesenteric Ischemia
Abnormal enhancement patterns
delayed on early phase;persistenton late phase
Complete absence of enhancement
very specific
very rare
Hyperemia-good prognosis
CT Angiography

84. Malabsorption
Role of radiology
To determine the cause
Possible complications
CT and MR-complementary
Specific pattern
Bacterial overgrowth syndromes
Adult coeliacds
Adult CF
ZES
Short bowel synd

85. Modifications in Barium techniques
•Enteroclysis –prefd
•Balloon-kept in distal duodenum
•Larger amt of barium (more than 300ml)
•Faster injection
•Early compression spot films reqd

86. Coeliac disease
•Lumen dilatation
•Fold thickening
•Less than 3
folds/inch -jejunum
•4-6 folds/inch
-ileum
jejunisation

87. Conclusion
barium studies –still 1
st
line of investigation
CT –can demonstrate extra-luminal
abnormalities
MR –upcoming,esp where repeated imaging is
required and radiation issues are a concern

88. Thank you