Diagnostic Ultrasound - Abdomen and Pelvis
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Diagnostic Ultrasound - Abdomen and Pelvis

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Ureters and Bladder – Distended bladder may cause ureteral and pelvicalyceal dilation and rescanning post void is beneficial to exclude obstruction ○ Color Doppler evaluation of bladder helps assess normal ureteral jets and helps exclude complete ureteral obstruction • Bladder ○ Recommend fluid intake prior to examination to ensure optimal distension of urinary bladder – In fully distended state, urinary bladder is easily visualized using transabdominal approach ○ Examine patient in supine position with transabdominal suprapubic approach – Perform scanning in sagittal and transverse planes – Patient may be placed in decubitus position, especially to determine mobility of intravesical masses or debris, if present – With smaller volumes, caudal angulation of transducer is needed to visualize urinary bladder in its retropubic location ○ Nature of cystic structure in pelvis may be ascertained by asking patient to void or by inserting Foley catheter ○ In some instances, transvaginal ultrasound may be used in women for evaluation of suspect bladder neck lesions, UVJ stone, or ureterocele ○ Advantages of ultrasound – Radiation-free, real-time assessment with high spatial resolution of bladder and bladder wall – Real-time assessment of intraluminal masses in bladder for mobility and vascularity – Real-time imaging guidance for bladder intervention, e.g., placement of percutaneous suprapubic catheters – Real-time assessment of ureteral jets using color Doppler imaging; particularly useful in pregnant patients with dilated collecting system • Large midline ovarian or pelvic cystic mass may simulate bladder on transabdominal ultrasound ○ Attention to normal bladder shape, rescanning after voiding to confirm empty bladder, or transvaginal imaging is helpful to differentiate Imaging Pitfalls • Bladder ○ Reverberation artifacts are commonly encountered behind anterior wall of urinary bladder – Appear as regularly spaced lines at increasing depth as a result of repeated reflection of ultrasound signals between highly reflective interfaces close to transducer – May be reduced or avoided by changing scanning angle or by moving transducer or using spacer ○ Underdistended bladder may give false impression of wall thickening and limits intraluminal assessment CLINICAL IMPLICATIONS Clinical Importance • Ureters are at high risk of inadvertent injury during abdominal or gynecological surgery due to close proximity to uterine (in uterosacral ligament) and gonadal arteries (at pelvic brim) • Ectopic ureter ○ Usually (80%) associated with complete ureteral duplication; more common in females ○ Ectopic ureteral insertion in females can occur in urethra, vagina leading to urinary incontinence ○ In complete duplication, upper moeity inserts ectopically inferiorly and distally to lower moeity (Weigert-Meyer rule) and can be associated with ureterocele ○ In duplicated system, upper moiety has higher predisposition to obstruction from ureterocele, while lower moiety has predisposition to vesicoureteral reflux • Ureterocele: Cystic dilation of intramural portion of ureter bulging into bladder ○ Orthotopic: Normal insertion of single ureter ○ Ectopic: Inserts below trigone, mostly in duplicated system • Ureteral duplication ○ Bifid ureter drains a duplex kidney but ureters unite before entering bladder • Extraperitoneal bladder rupture ○ Urine and blood distend prevesical space (Retzius) ○ Urine often tracks posteriorly into presacral space, superiorly into retroperitoneal abdomen ○ Usually caused by pelvic fractures • Intraperitoneal bladder rupture ○ Urine flows up paracolic gutters into peritoneal recesses and surrounds bowel ○ Usually caused by blunt trauma to an overdistended bladder ○ Bladder ruptures along dome, which is in contact with intraperitoneal space • Patent fetal urachus forms conduit between umbilicus and bladder ○ Urachus is normally obliterated to form median umbilical ligament ○ May persist as cyst, diverticulum, or rarely, fistula ○ May become infected or lead to carcinoma (adenocarcinoma) • Bladder diverticula are common ○ Congenital: Hutch diverticulum (near ureterovesical junction) ○ Acquired (usually due to chronic bladder outlet obstruction), associated with trabeculated bladder wall ○ Can lead to infection, stones, tumor SELECTED REFERENCES 1. Demir S et al: Value of sonographic anterior-posterior renal pelvis measurements before and after voiding for predicting vesicoureteral reflux in children. J Clin Ultrasound. ePub, 2014 2. Butler P, Mitchell A, Healy JC. Applied Radiological Anatomy. Cambridge University Press. 2012 3. Shimoya K et al: Diagnosis of ureterocele with transvaginal sonography. Gynecol Obstet Invest. 54(1):58-60, 2002 4. Djavan B et al: Bladder ultrasonography. Semin Urol. 12(4):306-19, 1994 5. Hayden CK Jr et al: Urinary tract infections in childhood: a current imaging approach. Radiographics. 6(6):1023-38, 1986 6. Glassberg KI et al: Suggested terminology for duplex systems, ectopic ureters and ureteroceles. J Urol. 132(6):1153-4, 1984 Anatomy: Pelvis 111

Ureters and Bladder Anatomy: Pelvis URETERS AND URINARY BLADDER IN SITU Ureteric branch from renal artery Superior mesenteric artery Gonadal (ovarian) arteries Left ureter Right ureter Inferior mesenteric artery Psoas muscle External iliac artery & vein Internal iliac artery Rectum Uterus Uterine artery Vaginal artery Ureteric branch from inferior vesical artery Superior vesical artery Urinary bladder The ureters receive numerous and highly variable arterial branches from the aorta, and the renal, gonadal, and internal iliac arteries. These vessels are short and can be easily ruptured by retraction of the ureter during surgical procedures. The arterial supply to the bladder is also quite variable. Both genders receive supply from the superior vesical arteries and from various branches of the internal iliac arteries. Branches to the prostate and seminal vesicles (men) also send branches to the inferior bladder wall. In women, branches to the vagina send arteries to the base of the bladder. Note how the ureters deviate anteriorly as they cross the external (or common) iliac vessels and pelvic brim. This may constitute a point of relative narrowing where the passage of ureteral calculi (stones) may be impeded. In the abdomen the ureters course along the psoas muscles. 112

Ureters <strong>and</strong> Bladder<br />

Anatomy: <strong>Pelvis</strong><br />

URETERS AND URINARY BLADDER IN SITU<br />

Ureteric branch from<br />

renal artery<br />

Superior mesenteric<br />

artery<br />

Gonadal (ovarian) arteries<br />

Left ureter<br />

Right ureter<br />

Inferior mesenteric artery<br />

Psoas muscle<br />

External iliac artery &<br />

vein<br />

Internal iliac artery<br />

Rectum<br />

Uterus<br />

Uterine artery<br />

Vaginal artery<br />

Ureteric branch from<br />

inferior vesical artery<br />

Superior vesical artery<br />

Urinary bladder<br />

The ureters receive numerous <strong>and</strong> highly variable arterial branches from the aorta, <strong>and</strong> the renal, gonadal, <strong>and</strong> internal iliac arteries.<br />

These vessels are short <strong>and</strong> can be easily ruptured by retraction of the ureter during surgical procedures. The arterial supply to the<br />

bladder is also quite variable. Both genders receive supply from the superior vesical arteries <strong>and</strong> from various branches of the internal<br />

iliac arteries. Branches to the prostate <strong>and</strong> seminal vesicles (men) also send branches to the inferior bladder wall. In women, branches<br />

to the vagina send arteries to the base of the bladder. Note how the ureters deviate anteriorly as they cross the external (or common)<br />

iliac vessels <strong>and</strong> pelvic brim. This may constitute a point of relative narrowing where the passage of ureteral calculi (stones) may be<br />

impeded. In the abdomen the ureters course along the psoas muscles.<br />

112

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