Magnetic resonance imaging of an infected urethral diverticulum: a case report

Cross-sectional imaging of the female urethra: technique and results

Clinical assessment of women with urethral symptoms is difficult, necessitating further evaluation with imaging. Urethrography provides limited information on luminal abnormalities of the urethra. Recent advances in ultrasound (US) and magnetic resonance (MR) imaging have dramatically improved evaluation of the female urethra, clarifying findings at physical examination and providing accurate road maps for surgeons. High-resolution transvaginal US, transperineal US, and transurethral US are reliable techniques for diagnosis and characterization of urethral abnormalities. High-resolution multiplanar MR imaging with phased-array pelvic and endovaginal coils demonstrates the urethral anatomy in greater detail. In women with urethral diverticula, US and MR imaging demonstrate the number of diverticula and the location, size, configuration, and possible contents of the sac. Most important, the position of the neck of the diverticulum may be identified for the surgeon. Imaging features do not allow differentiation between histologic subtypes of urethral carcinoma; the diagnosis is established with histopathologic examination. Periurethral cysts do not communicate with the urethra and therefore can often be differentiated from urethral diverticula at endocavitary MR imaging. High-resolution multiplanar US and MR imaging allow comprehensive evaluation of abnormalities of the female urethra.

Female urethral diverticula

Urethral diverticula are frequently under-diagnosed. The pathogenesis of this condition is poorly understood, and these lesions represent a spectrum of disorders ranging from isolated suburethral cysts to herniation of the urethral lining into the vaginal mucosa. Women with this disorder frequently complain of a host of symptoms referable to the lower urinary and genital tracts. Accurate diagnosis is based on history and clinical evaluation. Perineal ultrasound and MRI are often helpful. Repeated courses of antibiotics and urethral dilatation often fail to resolve the problem, and definitive intervention usually requires surgical excision to provide relief. This chapter describes the current management of this condition, and it heralds a re-look at the patho-aetiology in view of recent MRI findings of symptomatic non-communicating microcystic lesions.

MR imaging of the male and female urethra

Conventional radiographic contrast material-enhanced studies (eg, retrograde urethrography [RUG], voiding cystourethrography [VCUG], double-balloon catheter urethrography) and ultrasonography are useful in evaluating the anatomy of the urethra but are limited in demonstrating anatomic derangement of adjacent structures. Since the anatomic details of both the urethra and periurethral tissues can be evaluated noninvasively with magnetic resonance (MR) imaging, this modality can be used as an adjunctive tool for evaluation of urethral abnormalities. In patients with congenital anomalies, MR imaging is reserved for cases of intersex anomalies or complex genitourinary anomalies, in which evaluation of internal organs is essential. MR imaging may demonstrate diverticula that are not seen on radiographic contrast-enhanced studies, including VCUG, RUG, or double-balloon catheter study. In cases of inflammation, MR imaging can demonstrate not only inflammatory infiltration around the urethra but also the presence of a periurethral abscess or sinus tract. In cases of trauma, MR imaging is helpful in assessing the presence and extent of anterior or posterior urethral injury and predicting the occurrence of complications. At MR imaging, a fistula can be seen as a direct communicating channel with an adjacent organ. In patients with urethral tumors, the major role of MR imaging is in local staging.

Endoluminal magnetic resonance imaging in the evaluation of urethral diverticula in women

OBJECTIVES

Accurate determination of the size and extent of urethral diverticula can be important in planning operative reconstruction and repair. Voiding cystourethrography (VCUG) is currently the most commonly used study in the preoperative evaluation of urethral diverticula. We reviewed our experience with the use of endoluminal (endorectal or endovaginal) magnetic resonance imaging (eMRI) in these patients as an adjunctive study to VCUG to evaluate whether the MRI provided anatomically important information that was not apparent on VCUG.

METHODS

A retrospective analysis of all patients with a clinical diagnosis of urethral diverticula undergoing MRI at a single institution was performed. Patients were evaluated with history, physical examination, cystoscopy, VCUG, and eMRI. Endoluminal MRI was retrospectively compared to VCUG with respect to size, extent, and location found at operative exploration.

RESULTS

Twenty-seven consecutive patients underwent endorectal or endovaginal coil MRI in the evaluation of suspected urethral diverticula. Twenty patients subsequently had attempted transvaginal operative repair of the diverticulum. In 2 patients, eMRI demonstrated a urethral diverticulum, whereas VCUG did not. Operative exploration in these patients revealed a urethral diverticulum. In 14 of 27 patients, the VCUG underestimated the size and complexity of the urethral diverticulum as compared to eMRI and operative exploration. In 13 of 27 patients, the size, location, and extent of the urethral diverticulum on VCUG correlated well with the eMRI and/or operative findings.

CONCLUSIONS

We have found endorectal and endovaginal coil MRI to be extremely accurate in determining the size and extent of urethral diverticula as compared to VCUG. This information can be critical when planning the approach, dissection, and reconstruction of these sometimes complex cases.

The role of magnetic resonance imaging in problematic gynecologic diagnoses

MRI is a modality that provides excellent anatomic detail, especially of soft tissue and bone. Comparison of T1-weighted and T2-weighted images offers significant diagnostic information of pelvic pathology. In five problematic gynecologic cases, magnetic resonance imaging (MRI) provided key information for optimal treatment planning or a definitive diagnosis for the gynecologist.