Diagnostic ultrasound ( PDFDrive )

306 PART II Abdominal and Pelvic Sonography
A
B
C
D
FIG. 8.59 Traumatic Disruption of Anal Sphincter in Two Patients. (A) Cross-sectional and (B) long-axis views of the anal canal from a
transvaginal approach show disruption of the sphincter anteriorly from 9 to 3 o’clock. The arrow on the sagittal image shows the cephalad extent
of the internal anal sphincter. (C) Cross-sectional and (D) long-axis views of the anal canal show full-thickness disruption of the anterior anal canal
between 11 and 1 o’clock. The arrow in each image shows air bubbles within an anovaginal istula.
intersphincteric anal glands predominantly located at the dentate
line. his occurs most frequently in young adult men. Documentation
of luid collections and the relationship of inlammatory
tracts to the sphincter mechanism are important for surgical
treatment. We prefer transvaginal sonography (Video 8.17) in
conjunction with transperineal sonography in women and
transperineal sonography in men for evaluation of this problem.
Scans are performed with curved and high-frequency linear
probes placed irmly on the skin of the perineum between the
introitus and the anal canal in women and between the scrotum
and the anal canal in men. 111 Firm pressure on the transducer
is required to aford good visualization of the anal canal. We
begin the procedure with the transducer in the transverse
plane relative to the body. he transducer should be directed
cephalad and anterior to the plane of the anal canal, then angled
slowly through the plane of the anal canal, which will show it
in cross section from the anorectal junction to the external anal
Sonography of Perianal Inlammatory Disease
Internal opening in the anal canal or rectum
Tracts and their relationship to anal sphincter
External openings
Fluid collections
opening. Rotation of the transducer by 90 degrees will allow for
imaging in the longitudinal plane. Tracts and collections in the
perineum, buttocks, scrotum, and labia can also be assessed and
followed in a retrograde direction to their connection with the
anal canal.
Perianal inlammatory tracts and masses are classiied according
to Parks et al. 114 heir classiication provides an anatomic
description of istulous tracts, which acts as a guide to operative