Diagnostic ultrasound ( PDFDrive )

314 PART II Abdominal and Pelvic Sonography
FIG. 9.5 Anterior Junction Line. Sagittal sonogram demonstrates
an echogenic line that extends from the renal sinus to perinephric fat.
The defect is typically located at the junction of the upper and middle
thirds of the kidney, as in this example.
Sonographic Criteria for Hypertrophied
Column of Bertin
Indentation of renal sinus laterally
Bordered by junctional parenchymal defect
Location at junction of upper and middle thirds
Continuous with adjacent renal cortex
Similar color low to surrounding parenchyma
Contains renal pyramids
Less than 3 cm in size
Columns contain renal pyramids and usually measure less than
3 cm 7,8 (Fig. 9.6). he echogenicity of HCB and adjacent renal
cortex depend on the scan plane. Alterations in tissue orientation
produce diferent acoustic relectivity. 7 he echoes of the HCB
are brighter than those of adjacent renal cortex when seen en
face 7 (Fig. 9.6). It may be diicult to diferentiate a small, hypovascular
tumor from an HCB; however, demonstration of arcuate
arteries by color Doppler ultrasound indicates an HCB rather
than a tumor. Occasionally, contrast-enhanced computed
tomography (CT) may be necessary to diferentiate between an
HCB and a non–border-deforming renal lesion.
he kidney has a thin, ibrous capsule. he capsule is surrounded
by perirenal fat. Perirenal fat is encased anteriorly by
Gerota fascia and posteriorly by Zuckerkandl fascia. 9 he right
perirenal space opens superiorly at the bare area of the liver, and
both perirenal spaces communicate with the pelvic peritoneal
space. 10 Right and let perirenal spaces communicate with each
other across the midline at the level of the third to ith lumbar
vertebrae. 10
Ureter
he ureter is a long (30-34 cm), mucosal-lined conduit that delivers
urine from the renal pelvis to the bladder. Each ureter varies
in diameter from 2 to 8 mm. 3 As it enters the pelvis, the ureter
passes anterior to the common/external iliac artery. he ureter
has an oblique course through the bladder wall (see Fig. 9.3).
Bladder
he bladder is positioned in the pelvis, inferior and anterior to
the peritoneal cavity and posterior to the pubic bones. 3 Superiorly,
the peritoneum is relected over the anterior aspect of the bladder.
Within the bladder, the ureteric and urethral oriices demarcate
an area known as the trigone; the urethral oriice also marks
the bladder neck. he bladder neck and trigone remain constant
in shape and position; however, the remainder of the bladder
will change shape and position depending on the volume of
urine within it. Deep to the peritoneum covering the bladder is
a loose, connective tissue layer of subserosa that forms the
adventitial layer of the bladder wall. Adjacent to the adventitia
are three muscle layers: the outer (longitudinal), middle (circular),
and internal longitudinal layers. Adjacent to the muscle,
the innermost layer of the bladder is composed of mucosa. he
bladder wall should be smooth and of uniform thickness. he
wall thickness depends on the degree of bladder distention.
SONOGRAPHIC TECHNIQUE
he ability to visualize organs of the genitourinary tract by
ultrasound depends on the patient’s body habitus, operator
experience, and scanner platform. High-frequency probes should
be used for patients with a favorable body habitus. Harmonic
imaging is oten useful for diicult-to-scan patients (e.g., obese
patients). Compound imaging and speckle reduction may increase
lesion conspicuity and decrease artifacts.
Kidney
he kidneys should be assessed in the transverse and coronal
plane. Optimal patient positioning varies; supine and lateral
decubitus positions oten suice, although oblique and occasionally
prone positioning may be necessary (e.g., obese patients).
Usually, a combination of subcostal and intercostal approaches
is required to evaluate the kidneys fully; the upper pole of the
let kidney may be particularly diicult to image without a
combination of approaches. When the collecting system is dilated,
additional images should be taken to assess for the level of
obstruction, any obstructing lesion, and appearance of the kidneys
ater voiding (see “Hydronephrosis”).
Ureter
he proximal ureter is best visualized using a coronal oblique
view with the kidney as an acoustic window. he ureter is followed
to the bladder, maintaining the same approach. A nondilated
ureter may be impossible to visualize because of overlying bowel
gas. Transverse scanning of the retroperitoneum oten demonstrates
a dilated ureter, which can then be followed caudally with
both transverse and sagittal imaging. In women, a dilated distal
ureter is well seen with transvaginal scanning.
Bladder and Urethra
he bladder is best evaluated when it is moderately illed; an
overilled bladder causes patient discomfort. he bladder should
be scanned in the transverse and sagittal planes. To better visualize
the bladder wall in women, transvaginal scanning may be helpful.
If the nature of a large, luid-illed mass in the pelvis is uncertain,