• Normal ileocolic
• The role of plain radiography is limited and
only done for 2 reasons:
• To assess intestinal obstruction.
• To diagnose pneumoperitoneum.
1. Multiple air fluid levels > 2.
2. Wide air fluid levels > 2.5 cm.
3. Differential air fluid levels (2 air fluid levels of
different height > 2 cm in the same bowel loop).
4. Small bowel / colon diameter ratio > 0.5.
5. Step ladder configuration of small bowel loops
from LUQ to RLQ.
6. String of pearls sign (trapped air between the
valvulae conniventes along the superior wall of
the dilated bowel).
Step ladder configuration
String of pearls sign
• Air under diaphragm (erect).
• Air on both sides of the bowel wall (Rigler
• Air around the falciform ligament (supine).
Signs of pneumo-peritoneum
• Nodular pattern.
• Ulcero-nodular pattern.
• Straightening of the mesenteric border.
• Sacculation of the ante-mesenteric border.
• Wide separation.
• Pathology: mucosal ulcers with surrounding
translucent mound of edema.
• Fluid collection with thickened wall
• containing air or echogenic debris
• bright echoes with distal acoustic shadows
outside the boundaries of bowel loops.
• Heterogenous hypoechoic mass with
• No identifiable wall or fluid.
CT is less sensitive than barium studies in detection
of early mucosal changes (i.e ulceration).
CT is more sensitive than barium studies in detection
of extraluminal changes (mural or extraintestinal).
Circumferential mural thickening
In acute non cicatrizing phase:
Mural thickening with preserved stratification
and minimal luminal narrowing.
In chronic cicatrizing phase:
Mural thickening, with loss of mural stratification
and increased luminal narrowing.
• Normally the bowel wall measures less than
2 mm if well distended).
• The mean diameter in Crohn’s disease is 10
• If > 10 mm suspect pseudomembranous
• Segmental hyper-attenuation of distended
small bowel loops relative to nearby
• Mural hyper-enhancement indicates
• Sometimes associated with proximal
dilatation due to partial obstruction.
proliferation (Creeping fat):
• Adjacent to the actively inflamed segment.
• Of high density than the normal fat.
• Produce mass effect with displacement of the
adjacent bowel loops (DD with T.B).