Diagnostic ultrasound ( PDFDrive )

260 PART II Abdominal and Pelvic Sonography
FIG. 8.4 Gut Wall Pathology. Schematic of sonographic appearances with sonographic equivalents. Top, Intraluminal mass. Inlammatory
pseudopolyp on sonogram. Middle, Pseudokidney sign, with symmetrical wall thickening and wall layer destruction. Carcinoma of the colon on
sonogram. Bottom, Exophytic mass. Serosal seed on visceral peritoneum of the gut on sonogram. (With permission from Wilson SR. The bowel
wall looks thickened: what does that mean? In: Cooperberg PL, editor. RSNA categorical course syllabus. Chicago: RSNA; 2002. pp. 219-228. 1 )
allowing optimal resolution of structures close to the skin. Slow,
graded pressure is applied. Normal gut will be compressed
and gas pockets displaced away from the region of interest. In
contrast, thickened abnormal loops of bowel and obstructed
noncompressible loops will remain unchanged. Patients with
peritoneal irritation or local tenderness will usually tolerate the
slow, gentle increase in pressure of compression sonography,
whereas they show a marked painful response if rapid, uneven
scanning is performed.
Doppler Evaluation of Gut Wall
Normal gut shows little signal on conventional color Doppler
because interrogation is diicult in a normal and mobile bowel
loop. Both neoplasia and inlammatory disease show increased
vascularity compared with the normal gut wall (Fig. 8.6), whereas
ischemic and edematous gut tends to be relatively hypovascular.
he addition of color and spectral Doppler ultrasound evaluation
to the study of the gut wall provides supportive evidence that
gut wall thickening is caused by either ischemic or inlammatory