Journal of Postgraduate Medicine Medknow Publications and Staff Society of Seth GS Medical College and KEM Hospital, Mumbai, India ISSN: 0022-3859 EISSN: 0972-2823 Vol. 52, Num. 1, 2006, pp. 35-37

Journal of Postgraduate Medicine, Vol. 52, No. 1, January-March, 2006, pp. 35-37

Case Report

Virtual cystoscopy: Reality in imaging of bladder tuberculosis

Khanna ParitoshC, Kukreja KU, Merchant SA, Farooq M

Departments of Radiology and Urology, Lokmanya Tilak Municipal General Hospital, Sion, Mumbai-400 022, Maharashtra, India

Correspondence Address:Paritosh C. Khanna, E-mail: paritoshkhanna@hotmail.com

Code Number: jp06012

Abstract

Keywords: Bladder tuberculosis, conventional cystoscopy, virtual cystoscopy

Conventional cystoscopy, an invasive investigation, plays a key role in the diagnosis of urinary bladder diseases. Virtual cystoscopy (VC), derived from postprocessing of rapidly acquired multidetector computed tomography (MDCT) has been used for identification and characterization of bladder masses.[1],[2],[3],[4] The purpose of this case report is to essentially highlight the use and advantages of VC in tuberculous bladder lesions, such as ulcers, as an adjunct to basic imaging and as a tool that precedes conventional cystoscopic biopsies.

Case History

A 42-year-old female, symptomatic for the past 2 years, presented with complaints of dysuria, urinary urgency, frequency, and painless hematuria that was accompanied by intermittent episodes of passage of blood clots and clot colic. Her complaints included a continuous, dull, right flank pain, low-grade fever, and recurrent urinary tract infections refractory to antibiotics. Recent salient laboratory investigations revealed presence of anemia, leukocytosis, increased erythrocyte sedimentation rate (80 mm at the end of 1 h), and serum creatinine level of 1.8 mg/dl. Urinary polymerase chain reaction was positive for tuberculosis (TB). However, urine was negative both for acid fast bacilli and culture.

Chest radiographs were normal. Ultrasound [Figure - 1] of the urinary tract revealed bilateral mild-moderate renomegaly, moderate right hydroureteronephrosis, severe hydronephrosis of the left kidney, and a small capacity bladder with a distinct solitary ulcer with undermined edges. MDCT of the abdomen was performed [Figure - 2]; Siemens Volume Zoom, Forchheim, Germany). The scanner employed a 0.5-s gantry rotation speed, eight detector rows, and four image acquisition systems. Plain, contrast-enhanced [with 120-ml nonionic iodinated contrast intravenously (IV, iopromide, Ultravist 370, Schering)], and delayed scans were obtained at 120 kV/250 mA. Collimation of 5 mm was used, except for the plain and delayed scans of the bladder region, where 1.25-mm collimation was used. Effective dose of the entire examination was 14.4 mSv. Prior to the delayed scan, alternate supine/prone patient positions were performed five times to facilitate adequate contrast-urine mixing in the bladder. CT, in addition to confirming the ultrasound findings, revealed that the right ureter had a stricture in its lower third segment and the left kidney was nonfunctioning. The MDCT-derived volume dataset (of the contrast-filled bladder on delayed scan) was used to generate VC images [Figure - 3] on a workstation (3D Virtuoso, Silicon Graphics, Mountain View, CA) that confirmed the right posterior wall ulcer, superior to the trigone, and the right ureteric orifice. A diethyl triamine penta-acetic acid (DTPA) renogram confirmed left renal dysfunction.

A conventional cystoscopic biopsy [Figure - 4]; Karl Storz 30° cystoscope with Storz Endocamera, passed through a 21-French rigid sheath) was obtained from the solitary ulcer edge. Histopathological examination [Figure - 5] demonstrated the presence of multiple caseating granulomas and Langhans giant cells. A left-sided total nephrectomy was subsequently performed, which revealed tuberculosis.

Discussion

Persistent cystitis refractory to antibiotics and presence of pus and red cells in the urine without bacteria on routine culture should arouse suspicion of urinary TB, particularly in young adults. Mycobacteria enter the urine from the pelvicalyceal system of the infected kidneys, leading to bladder mucosal inflammation and formation of tubercles. As in our case, these tubercles may coalesce and ulcerate. This is a common occurrence around the ureteric orifices and trigone, ultimately leading to bladder wall destruction, scarring, ureteric fibrosis, and ureteral stricture formation and thickening (usually in the lower-third), which, in turn, leads to hydronephrosis or pyonephroses. Symptoms of chronic cystitis, loin discomfort, and constitutional derangement predominate.

Ultrasound depicts bladder-wall thickening, contraction, vesicoureteric reflux, calcifications, and ulcerations.[5] In our case, ultrasound and CT, by virtue of their cross-sectional capability, depicted a side-on view of a typical tuberculous ulcer, with irregular, ragged, and undermined edges. CT is useful, but without adequate bladder distension and thin-slice scanning, it has low sensitivity for detection of small bladder lesions.[6] MDCT circumvents these limitations. MDCT and VC are proven tools for the detection and evaluation of bladder tumors.[1],[2],[3],[4] CT data acquisition protocols used to generate VC employ either air or contrast material.[1],[2],[3],[4] IV contrast-mediated bladder filling is easier, convenient, and less invasive than air which involves catheterization and doubled radiation doses.[6],[7] VC can be generated from routine contrast-enhanced CT, and the entire urinary tract imaged with one comprehensive examination. We employed a volume-rendering algorithm after scanning the contrast-laden bladder for generation of VC images, which is superior to surface rendering because it retains raw data and provides better mucosal detail.[6]

VC has the potential to localize and characterize lesions in a manner similar to conventional cystoscopy. As it provides an en face view of lesions, surgeons can proceed with conventional cystoscopy with a mental image of the lesion, when a cystoscopic biopsy or follow-up is contemplated.[6] It requires fewer steps for patient preparation, is inexpensive, and patient compliance is not an issue, which are the basic attributes of a screening test. In conjunction with axial and multiplanar images, both endoluminal and exoluminal information are gathered. Unlike ultrasound and CT, the endoluminal perspective helped us obtain an en face view of the ulcer. A VC study is rapidly and easily generated (and can be done while the patient is in the scanner) as the bladder has a simple luminal anatomy, small volume, and no involuntary peristalsis.[6] Other potential indications are as follows: patients who decline invasive diagnostic tests, unfit patients (distal urinary obstruction, active hematuria, and bladder substitutions), and early postoperative period.[5],[6]

However, at the time of writing, VC is unable to depict small (< 5 mm), flat lesions that conventional cystoscopy can depict as subtle, mucosal alterations. Benign (inflammatory/tuberculous/fibrous) and malignant mucosal thickening may be indistinguishable; conventional cystoscopy and biopsy often become imperative. VC, for obvious reasons, is unable to provide tissue diagnosis, an ability possessed by cystoscopic-biopsy. Ionic contrast, rarely used in current practice, is contraindicated in allergic patients and those with bilateral renal malfunction.[6] Magnetic-resonance-imaging VC is comparable with conventional and CT cystoscopy,[8] and can be used where contrast-enhanced CT is contraindicated. Nevertheless, VC holds promise in the evaluation of large bladder ulcers and adds a "third imaging dimension" that resembles conventional cystoscopy. Although more extensive evaluation is required, our case underscores its role in preliminary bladder "exploration." This imaging advancement can serve as a follow-up tool for patients with bladder lesions and to monitor healing during and after treatment. Continuously evolving technology is making virtual detection of smaller lesions a reality.

References

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