Imaging

Most calyceal diverticula are found by the intravenous pyelograms. With the aid of tomograms and oblique films, intravenous pyelograms can demonstrate the anterior-posterior orientation of the diverticulum; however, it may not clearly demonstrate the communicating neck or the renal parenchyma. Cystoscopy with ureteral catheterization and retrograde pyelography may be necessary not only to localize symptoms but also to better identify the width, length, and location of the diverticular neck. This is particularly useful when an endourologic approach is considered.

Computed tomography scan enables precise localization of the lesion as well as demonstrates its relation to surrounding structures. Most importantly, it allows for characterization of the renal parenchyma overlying the calyceal diverticulum, which is paramount in selecting patients for a laparoscopic approach.

Recently, a novel computed tomography protocol has been described in which noncontrast computed tomography is performed prone during inspiratory and expiratory phases (7). Three-dimensionally rendered images clearly demonstrate the anatomic relationship between the diverticulum, the parietal pleura, and retroperitoneal organs, and may identify patients in whom a percutaneous approach may not be safe or feasible, warranting a laparoscopic approach.

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