Diagnostic ultrasound ( PDFDrive )

CHAPTER 8 The Gastrointestinal Tract 307
treatment. he four main subtypes are intersphincteric (between
internal and external sphincter), transsphincteric (crossing both
internal and external anal sphincter into ischiorectal or ischioanal
fossa), suprasphincteric, and extrasphincteric. In each patient,
we also document the internal opening and the external openings,
as possible. Tracts show on the ultrasound scan as hypoechoic
linear areas or luid-containing tubular areas, depending on
their size and activity (Fig. 8.60). As with istulas elsewhere,
air bubbles within the tract show as bright, echogenic foci that
may move during the scan, helping with their identiication.
In our initial experience with 54 patients with perianal inlammatory
masses, sonographic indings were conirmed in 22 of
26 patients (85%) who underwent surgical treatment for their
disease.
Acknowledgment
he author would like to acknowledge Gordana Popovich for
her artwork.
A B C
D E F
G H I
FIG. 8.60 Perianal Inlammatory Disease in Nine Patients. Top row, Simple inlammatory openings and tracts (arrows). Cross-sectional
images of the anal canal show internal opening at 1 o’clock with (A) transsphincteric tract running to a small collection; (B) intersphincteric tract;
(C) larger extrasphincteric tract. Middle row, More complex tracts (arrows). (D) Anterior extrasphincteric tract shows luid within. (E) Bilateral,
complex, intersphincteric tracts and collections show bright, echogenic foci representing extraluminal air. (F) Boomerang, or horseshoe, tract
surrounds the anal canal posteriorly and laterally. There are internal openings at 2, 4, and 9 o’clock. Bottom row, Perianal abscesses (A). (G)
Abscess on left posterolateral aspect of the anal canal is particle illed. (H) Large, posterior abscess is complex, with a dependent debris level.
(I) Large, posterior abscess shows a large internal opening posteriorly at 6 o’clock.