Diagnostic ultrasound ( PDFDrive )

268 PART II Abdominal and Pelvic Sonography
basis were high and not signiicantly diferent for ultrasound
(89.7%), MRI (93.0%), and CT (84.3%). 19 herefore in this era
of cost and radiation awareness, ultrasound is rising in importance
for imaging of IBD. 20 Sonography is our routine evaluation
technique for initial disease diagnosis, the detection of recurrence,
21 the determination of the extent, complications 22 and
activity of disease, and in the assessment of response to
treatment.
Although any portion of the gut may be involved, Crohn
disease most commonly afects the terminal ileum and the
colon. his transmural, granulomatous inlammatory process
afects all layers of the gut wall and also the perienteric sot
tissues. Grossly, the gut wall may become very thick and rigid
with secondary luminal narrowing. Discrete or continuous
ulcers and deep issures are characteristic, frequently leading
to istula formation. Mesenteric lymph node enlargement and
matting of involved loops are common. he mesentery may be
markedly thickened and fatty, creeping over the edges of the
gut to the antimesenteric border. he classic features of Crohn
disease—wall thickening, inlammatory fat, lymphadenopathy,
and hyperemia—relect these gross morphologic changes.
Complications of Crohn disease include stricture, incomplete
bowel obstruction, perforation, istulas, and inlammatory
masses. 21
he immediate objectives of a sonogram on a patient with
known or suspected IBD, therefore, include documentation of
the distribution and the extent of the disease, as well as the
disease activity. A global assessment is made on ultrasound
grading all of the classic features from 0, not present; through
1, mild; 2, moderate; and 3, showing severe change 23 (Table 8.2).
Utilization of such a scoring system allows for consistency of
performance and reproducibility of results. It also facilitates
comparisons for monitoring response to therapy.
Crohn Disease on Sonography
CLASSIC FEATURES
Gut wall thickening
Inlammatory fat
Mesenteric lymphadenopathy
Hyperemia
COMPLICATIONS
Strictures
Mechanical bowel obstruction
Perforation
Inlammatory masses
Fistulas
Appendicitis
TABLE 8.2 Ultrasound Global Assessment Showing Crohn Disease Activity Scores on Gray-
Scale Ultrasound and Color Doppler Imaging
Gray-Scale
Ultrasound
Features of
Activity
Wall thickness
(mm)
Inlammatory
fat
Color Doppler
imaging
(CDI)
Mural blood
low
Ultrasound
global
assessment
Classiication
INACTIVE MILD MODERATE SEVERE
<4.0 4.0-6.0 6.1-8.0 >8.1
• Absent
• Perienteric region
resembles normal
mesenteric fat
• Absent
• No signs of active
disease
• Masslike
• Slightly echogenic
• Of less area than
the bowel on axial
view
• Small regions of
color without the
vessel
• Mild wall thickness
• Minimal
inlammatory fat
• Present but not
minimal signal on
CDI
• Wall layer
preservation
• Masslike
• More echogenic
• Equal area to
the bowel on
axial view
• Medium-length
segments of
color vessels in
the bowel wall
• Moderate wall
thickness
• Moderate
inlammatory fat
• Moderate signal
on CDI
• ± Wall layer
preservation a
• Masslike
• Signiicantly echogenic
• Of greater area than the
bowel on axial view
• Circumferential or
continuous depiction of
vessels in the bowel wall
with or without mesenteric
vessels
• Moderate to severely
thickened bowel wall
• Abundant inlammatory fat
• Long continuous mural
blood vessels on CDI
• ± Wall layer preservation a
• Spiculation of serosal
border a
a Loss of wall layering and serosal spiculation both suggest increasing disease severity.
Reproduced with permission from Medellin-Kowalewski A, Wilkens R, Wilson A, et al. Quantitative contrast-enhanced ultrasound parameters in
Crohn disease: their role in disease activity determination with ultrasound. AJR Am J Roentgenol. 2016;206(1):64-73. 23