imaging modalities of intestinal obstruction mithilesh kumar medical college kolkata
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Mithilesh Kumar Medical College kolkataTRANSCRIPT
IMAGING MODALITIES IN INTESTINAL OBSTRUCTIONBy – MITHLESH KUMAR
Third Professional MBBS Part – IIMedical College Kolkata
OVERVIEW
• Radiography• Computed Tomography• Magnetic Resonance Imaging• Ultrasonography• Nuclear Imaging• Angiography
Radiography
• Plain upright abdominal X – Ray• Conventional barium follow – through
examination and enteroclysis• Barium enema study
Radiological features of plain X - Ray
• Small bowel – straight segments generally central and lie transversely
• Jejunum – valvulae conniventes, spaced regularly, concertina or ladder effect
• Ileum – featureless• Caecum – rounded gas shadow in right iliac fossa• Large bowel except caecum – haustral folds, spaced
irregularly
Some special points• In intestinal obstruction fluid level appear later than gas shadow as it takes
time for gas and fluid to separate• In adults, two inconstant fluid levels – one at the duodenal cap and the
other in the terminal ileum may be regarded as normal • In infants fluid levels in small bowel may be physiological, in this age group
it is difficult to distinguish large from small bowel in the presence of obstruction because the characteristic features seen in adults are not present or are unreliable
• In small bowel the number of fluid levels is directly proportional to the degree of obstruction and to its site, the number increasing the more distal the lesion
• Limited water soluble enema differentiates large bowel obstruction from pseudo-obstruction
Supine view of the abdomen in a patient with intestinal obstruction. Dilated loops of small bowel are visible(arrows)
Upright view of abdomen in a patient with intestinal obstruction,Showing multiple air fluid levels
Lateral decubitus view of abdomen, showing air fluid levels consistent with intestinal obstruction (arrows)
Plain abdominal radiograph shows dilated loops of small bowel associated with thickened edematous valvulae conniventes
Barium follow - throughFollowing features may assist in diagnosis
• Delay in the transit time• Snakehead appearance• Beak sign• Fixation and kinking
The contrast enhanced study shows dilated loops of small bowel with stretching of the mucosal folds and a narrowed segment ending in a beak
(arrow)
EnteroclysisDivide small bowel obstruction into 3 groups
• Low – grade or incomplete obstruction• High – grade obstruction • Complete small – bowel obtruction
Barium enema study
• Useful in large bowel obstruction• In children with intussusception it is
diagnostic as well as therapeutic
Postevacuation image from part of a barium enema study, shows a coiled spring appearance at the hepatic flexure of the colon typical of an intussusception
Computed Tomography
• Recommended when initial clinical findings and plain radiographs are inconclusive
• When strangulation is suspected• Clearly demonstrate abnormalities of bowel
wall, mesentery, mesenteric vessels, peritoneum
• Should be performed with intravenous contrast enhancement
Axial computed tomography scan showing dilated, contrast filled loops of the bowel on the patient’s left( yellow arrows), with decompressed distal small bowel on the patient’s right(red arrows)
Magnetic Resonance Imaging
• Assessment of small – bowel obstruction with strangulation
Ultrasonography
• It is of particular value in looking at the dynamics of the small bowel
• Used to assess peristalsis
A sonogram of right iliac fossa shows a bowel mass
Nuclear Imaging
• White blood scanning for detection and localization of intra abdominal inflammatory disease
99mTc HMPAO labeled white blood cell scan shows active uptake of the radionuclide in the terminal ileum and caecum/ascending colon indicative of an active inflammatory process
Angiography
• Superior mesenteric angiography used in diagnosis of internal herniation, intussusception, volvulus, malrotation, and adhesions.
Imaging in Intussusception
• Plain abdominal X – Ray shows features of small and large bowel obstruction
• Barium follow through of ileocolic intussusception shows claw sign
• Abdominal ultrasonography demonstrate doughnut appearance
‘Claw ‘sign of iliac intussusception , the barium in the intussusception is seen as a claw around a negative shadow of the intussusception
Postevacuation image from part of a barium enema study shows a coiled spring appearance in the region of caecum suggestive intussusception
Imaging in Volvulus
Caecal volvulus – bird beak deformity in barium enema
Sigmoid volvulus – dilated loop
Grossly dilated loop of bowel in the central abdomen with the ends of the loop pointing towards the right half of the pelvis
Shows a medially pointed end column of the barium (beak sign) in the mid ascending colon