Diagnostic ultrasound ( PDFDrive )

CHAPTER 9 The Kidney and Urinary Tract 335
A
B
C
D
FIG. 9.36 Gas Within the Bladder; Emphysematous Cystitis. (A) Transverse sonogram shows intraluminal gas along left anterior bladder
wall. Note “dirty” posterior shadowing. (B) Corresponding CT in this patient with conirmed emphysematous cystitis shows mild bladder wall
thickening and adjacent gas. (Courtesy of Shweta Bhatt, MD.) (C) Iatrogenic air introduced at cystoscopy appears as a nondependent bright
echogenic focus with multiple relection artifacts. (D) Enterovesical istula (arrow) showing gas in the bladder as multiple bright echogenic foci on
a transvaginal sonogram.
calculi that are nonobstructing are usually asymptomatic. Patients
with small caliceal calculi may have gross or microscopic
hematuria and may have colic symptoms despite the lack of
imaging indings suggestive of obstruction. 87 A calculus that
migrates and causes infundibular or UPJ obstruction oten results
in clinical signs and symptoms of lank pain. If a stone passes
into the ureter, the calculus may lodge in three areas of ureteric
narrowing: just past the UPJ; where the ureter crosses the iliac
vessels; and at the UVJ. he very small diameter of the UVJ
(1-5 mm) accounts for the large percentage of calculi that lodge
within the distal ureter. 86 Approximately 80% of stones smaller
than 5 mm will pass spontaneously.
Renal calculi can be detected using many diferent imaging
modalities, including plain ilms, tomography, intravenous
urography, ultrasound, and unenhanced CT. Sensitivities of 12%
to 96% for the ultrasound detection of calculi have been reported.
his wide discrepancy is a result of difering deinitions (renal
or ureteral), composition, and sizes of calculi. 88 Stones greater
than 5 mm were detected with 100% sensitivity by ultrasound.
Ultrasound with or without plain radiography competes favorably
with unenhanced CT in select patients with ureteral colic. 89-91
he sensitivity of ultrasound detection of urinary calculi in
patients with acute lank pain is 77% to 93%. 92-94 he 2016
European Association of Urology guidelines for diagnosis and