MR imaging of the penis.

The signal intensity of the corpora cavernosa of the penis at magnetic resonance (MR) imaging may vary from that of the corpus spongiosum; this difference is dependent on the rate of blood flow within the cavernous spaces that constitute the corporal bodies. Also visible at MR imaging are the layers of fibrous tissue that envelop the corporal bodies, the deep arteries and veins, subcutaneous connective tissue, tunica dartos, epidermis, and urethra. While the iliac, pudendal, perineal, and common penile arteries can be evaluated with three-dimensional MR angiography, the smaller end arteries of the penis have not yet been reliably demonstrated. MR imaging may be used to detect and stage penile and urethral cancers, identify and characterize benign penile masses, evaluate arteriogenic impotence, identify penile fractures, evaluate penile prostheses, localize periurethral abscesses, and identify plaques of Peyronie disease. With its direct multiplanar imaging capabilities, superb soft-tissue contrast, and excellent spatial resolution, high-field surface coil MR imaging can show the soft-tissue and vascular anatomy of the penis, as well as the appearance of many penile diseases.

Simultaneous upper and lower urinary tract obstruction associated with severe genital prolapse: diagnosis and evaluation with magnetic resonance imaging.

Genital prolapse causing both urethral and ureteral obstruction is an infrequent occurrence, especially in the absence of uterine prolapse. We report on a patient with massive genital prolapse causing both urethral and ureteral obstruction in whom magnetic resonance imaging demonstrated the level of obstructive uropathy and, after surgical repair of the prolapse, confirmed restoration of the normal pelvic and upper urinary tract anatomy.

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.

Urologic complications of Crohn's disease.

Crohn's disease frequently can affect the genitourinary system, mainly in the form of urinary fistulae and urolithiasis. Diagnostic evaluation of fistulae associated with Crohn's disease has improved with the increasing use of computed tomography and MR imaging, along with other diagnostic modalities. Resective surgery is the main treatment in this group of patients. Kidney stones are common because of metabolic derangements and dehydration; however, these can be treated adequately with minimally invasive procedures, such as extracorporeal shock-wave lithotripsy, ureteroscopy, and percutaneous surgery. In addition, medical therapies can prevent recurrent stones.

Injected periurethral collagen for postprostatectomy urinary incontinence: MR and CT appearance.

BACKGROUND: Urinary incontinence, a disturbing complication of radical prostatectomy, is often treated with periurethral collagen injections to increase urethral closure and resistance to urinary outflow. METHODS: Using magnetic resonance imaging and computed tomography, we studied the appearance of glutaraldehyde cross-lined bovine collagen endoscopically injected into the periurethral tissues in four men who developed urinary incontinence after radical prostatectomy. Collagen was also scanned in vitro to verify its magnetic resonance appearance. RESULTS: Collagen deposits appear as well-circumscribed nodules of low to intermediate signal intensity on both T1- and T2-weighted images in the periurethral tissues or in the base of the subjacent penile bulb (base of corpus spongiosum). On contrast-enhanced computed tomography, collagen appears as a hypoattenuating nodular-filling defect within the penile bulb. CONCLUSION: These imaging characteristics should allow differentiation of collagen from locally recurrent prostate carcinoma and avoid inappropriate work-up of benign findings.

Imaging urologic complications of pancreas transplantation with bladder drainage.

Urologic complications of bladder-drained pancreas transplants include cystitis, duodenitis and urethritis; duodenal ulceration and perforation; and periallograft fluid collections. These complications are readily depicted radiographically, and their recognition may be crucial for patient management.

Ventral hernia of the urinary bladder with mixed urinary incontinence: treatment with herniorrhaphy and allograft fascial sling.

Abdominal hernias are not rare in women with urinary incontinence, but incisional bladder hernia is uncommon. The presenting symptoms in the rare cases reported included suprapubic discomfort, irritative voiding symptoms, and urinary incontinence. We present a patient with bladder herniation and severe mixed urinary incontinence. The pathophysiology of the urinary symptoms and the surgical alternatives for the correction of this condition are discussed.

Angiomyolipoma of the renal sinus: diagnosis by percutaneous biopsy.

We report a case of angiomyolipoma of the renal sinus discovered incidentally during an evaluation for microscopic hematuria. Diagnosis was confirmed by percutaneous aspiration biopsy performed with magnetic resonance imaging control allowing differentiation of this entity from other fatty tumors of the renal sinus including liposarcoma, lipoma, and sinus lipomatosis.

Epidermoid cysts of the testicle: sonographic and MR imaging features.

OBJECTIVE: The purpose of this study is to analyze the appearance of testicular epidermoid cysts on high-resolution sonography and MR imaging and correlate imaging features with histopathologic findings. CONCLUSION: Intratesticular epidermoid cysts may show imaging features that correlate with their histopathologic findings. Concentric rings of alternating hypo- and hyperechogenicity on sonography and alternating high and low signal intensity on MR imaging ("onion ring" appearance) correspond to the pathologic finding of multiple layers of keratin debris. Absence of flow on color Doppler sonography and absence of contrast enhancement on MR imaging is also consistent with the avascular nature of these lesions. The ability of preoperative imaging studies to suggest the diagnosis of epidermoid cyst may prompt a testis-sparing surgery instead of an orchiectomy.

Renal neoplasms amenable to partial nephrectomy: MR imaging.

PURPOSE: To determine the magnetic resonance (MR) imaging characteristics of renal lesions in patients who undergo technically successful partial nephrectomy. MATERIALS AND METHODS: Between February 1991 and September 1997, 38 patients (41 lesions) who underwent partial nephrectomy at a single institution were preoperatively evaluated with contrast material-enhanced, multiplanar, surface-coil MR imaging. Imaging findings that could affect the decision to perform partial nephrectomy were retrospectively evaluated: tumor size; tumor location; presence of pseudocapsule; suspected tumor invasion of renal sinus fat, renal collecting system, renal vein, or perinephric fat; and morphologic and physiologic status of the contralateral kidney. Correlation was made with surgical and pathologic findings. RESULTS: Thirty-three of 41 lesions (80%) were renal cell carcinomas, five were oncocytic neoplasms (12%), two were hemorrhagic cysts (5%), and one was an angiomyolipoma (2%). Twenty-four of 41 (59%) lesions had pseudocapsules. In most cases, the perinephric fat (n = 38 [93%]), the renal sinus fat (n = 31 [76%]), and the renal collecting system (n = 39 [95%]) were correctly interpreted as being uninvolved by tumor. CONCLUSION: Renal neoplasms amenable to partial nephrectomy can be identified and characterized with contrast-enhanced, multiplanar, surface-coil MR imaging.

Efficacy of prone positioning during intravenous urography in patients with hematuria or urothelial tumor but no obstruction.

RATIONALE AND OBJECTIVES: The authors prospectively explored the efficacy of using prone positioning during intravenous urography to improve diagnostic visualization and eliminate the need for retrograde pyeloureterography in patients with no obstruction but with hematuria, history of urothelial tumor, or abnormal results of urine cytology. MATERIALS AND METHODS: Prone radiography was added to the usual intravenous urography protocol in 510 patients (347 men, 163 women) without urinary tract obstruction. Interpretations of intravenous urograms and recommendations for retrograde pyeloureterography were made before and after evaluation of the prone image. RESULTS: Confidence in the urographic interpretation was improved with acquisition of the prone radiograph in 100 of 510 patients (19.6%) (95% confidence interval, 82.1, 118). Retrograde pyeloureterography was obviated in 46 of 510 patients (9.0%) (95% confidence interval, 33.1, 58.9). The prone image was most helpful in evaluating the distal ureters (sacral and pelvic segments). CONCLUSION: Prone patient positioning during intravenous urography is useful when complete visualization of the upper urinary tract is desirable. Obtaining the additional image is cost-effective, even when only a few retrograde pyeloureterography studies are obviated.

High-resolution MR imaging of the vagina.

High-resolution magnetic resonance (MR) imaging with pelvic phased-array and endoluminal coils provides information on vaginal abnormalities heretofore not available with other imaging modalities. Congenital anomalies of the vagina can result from disorders of lateral fusion of the descending müllerian ducts and ascending urogenital sinus, developmental absence of the müllerian ducts, or disorders of vertical fusion. In these conditions, MR imaging can depict the presence or absence of the vagina, cervix, and uterus and help determine whether these structures contain a septum or are duplicated or distended with blood. Gartner duct cysts and Bartholin gland cysts have the same signal intensity characteristics, but the former are located in the anterolateral aspect of the proximal third of the vagina and the latter are in the posterolateral portion of the lower vagina. Entero-, vesico-, and ureterovaginal fistulas result from obstetric and surgical trauma, radiation therapy, or inflammatory bowel disease. MR imaging has great potential for detection and characterization of these fistulas. MR imaging can be used to detect and stage primary and secondary vaginal tumors. However, neither signal intensity nor patterns of enhancement enable confident prediction of the histologic subtype of vaginal malignancy.

Multicoil MR imaging of symptomatic female urethral and periurethral disease.

High-resolution magnetic resonance (MR) imaging with phased-array pelvic and endorectal coils has dramatically enhanced the ability to visualize abnormalities of the female urethra and periurethral tissues. These include developmental abnormalities (eg, urethral duplication, ectopic ureterocele), benign processes (eg, urethral diverticulum, caruncle, leiomyoma, trauma, and fistula; stress incontinence; paravaginal cyst), and malignant processes (eg, primary urethral carcinoma, secondary urethral malignancies). High-resolution MR imaging can be used to assess complications such as fistula formation and periurethral abscess, localize various entities, exclude pathologic processes whose presence could lead to an incorrect diagnosis, differentiate processes that might be confused at physical examination, and contribute to surgical planning and facilitate surgical correction.

Vesicourethral anastomotic strictures after radical prostatectomy: efficacy of transurethral balloon dilation.

PURPOSE: To assess the efficacy of transurethral balloon dilation of vesicourethral anastomotic strictures after radical retropubic prostatectomy. MATERIALS AND METHODS: Forty-five consecutive patients in whom vesicourethral anastomotic strictures developed after radical prostatectomy underwent fluoroscopically guided transurethral balloon dilation (n = 27), cystoscopically guided transurethral incision of the bladder neck (n = 10), or dilation performed by urologists who used various techniques (n = 8). RESULTS: Transurethral balloon dilation was successful in 16 (59%) of 27 patients. Ten of the 11 patients who did not respond favorably underwent transurethral incision of the bladder neck. Seven (70%) of these patients required either repeat attempts or subsequent balloon dilation. New urinary incontinence developed in one patient treated primarily with transurethral incision of the bladder neck but in no patients treated with transurethral balloon dilation. CONCLUSION: Anastomotic strictures after radical prostatectomy can be effectively treated with transurethral balloon dilation with no serious complication. Refractoriness to balloon dilation may be related to the presence of dense scar tissue.

Voiding cystourethrography after radical prostatectomy: normal findings and correlation between contrast extravasation and anastomotic strictures.

OBJECTIVE: Vesicourethral anastomotic strictures are an important complication of radical prostatectomy for prostatic cancer. Their formation has been attributed to extravasation of urine at the anastomosis and to the surgical technique used to construct the anastomosis. Our study examines whether the formation of a vesicourethral anastomotic stricture correlates with (a) contrast extravasation seen on postoperative voiding cystourethrograms and (b) the surgical technique used to construct the vesicourethral anastomosis. We also describe the postoperative appearances of the anastomosis. MATERIALS AND METHODS: One hundred and forty-two patients who underwent radical retropubic prostatectomy at our institution between June 1, 1987, and December 31, 1991, were included in the study. Of these, 101 had a direct end-to-end vesicourethral anastomosis, and 41 had their anastomosis constructed with traction sutures (Vest procedure). Voiding cystourethrograms were obtained 3 weeks after the prostatectomy. The appearance of the anastomosis, the presence of extravasation of contrast material at the anastomotic site, and the relationship of the subsequent formation of an anastomotic stricture to extravasation were evaluated. The influence of the surgical technique used to construct the vesicourethral anastomosis on the development of anastomotic strictures was analyzed. RESULTS: Contrast extravasation at the anastomotic site was seen in 14 (14%) of 101 patients who had a direct procedure and in three (7%) of 41 patients who had a Vest procedure. No relationship was found between contrast extravasation and subsequent formation of a stricture. Anastomotic strictures occurred in 16 (16%) of 101 patients who had a direct anastomosis and in 12 (29%) of 41 patients who had a Vest procedure. The surgical technique used to construct the vesicourethral anastomosis influenced the appearance of the vesicourethral anastomosis on cystourethrograms. CONCLUSION: Contrast extravasation at the anastomotic site is not infrequently seen on voiding cystourethrograms obtained after radical retropubic prostatectomy and resolves with continued drainage via a Foley catheter. As long as catheters are left in place until anastomotic healing is complete, extravasation of contrast material (implying urine extravasation at the anastomotic site) does not influence the subsequent formation of anastomotic strictures. Anastomoses that heal more slowly are no more likely to develop strictures than normally healing ones. Construction of the vesicourethral anastomosis by using the Vest procedure is a significant risk factor for stricture formation.

Balloon dilation of ureteral strictures after renal transplantation.

Ten ureteral strictures that developed in nine patients after renal transplantation were managed with balloon catheter dilation and placement of a ureteral stent. Four strictures were successfully dilated (40%), with a follow-up of 15-42 months (mean, 29 months). Comparison of these cases with the six cases of unsuccessfully dilated strictures failed to show any substantial differences between the groups with respect to demographics, stricture characteristics, or radiologic management techniques. However, strictures that developed at the ureteroneocystostomy site responded favorably more often (three of four strictures) to balloon catheter dilation than did strictures in other locations. The authors' experience is not as favorable as that of others who have managed renal transplant-related ureteral strictures in a similar manner. Nonetheless, their experience reinforces the efficacy of balloon catheter dilation of ureteral strictures that develop after renal transplantation as an effective alternative to surgical revision in a substantial percentage of patients.