Renal Parenchyma calcifications

Classic signs in uroradiology

The language of radiology is rich with descriptions of imaging findings, often metaphorical, which have found common usage in the day-to-day practice of genitourinary radiology. These "classic signs" give us confidence in our diagnosis. Some of the signs have become so familiar to us that they are referred to as an "Aunt Minnie." When the sign is invoked, or an Aunt Minnie is recognized, it often brings an impression of the image to mind, and it may have specific diagnostic and pathologic implications. The article uses classic signs accumulated from the literature to review a variety of pathologic conditions in the urinary tract.

Acetazolamide-induced nephrocalcinosis

Nephrocalcinosis has been reported in patients treated with acetazolamide and other agents, such as furosemide or bicarbonate. We present a case of nephrocalcinosis induced solely by acetazolamide and diagnosed radiographically. Possible mechanisms of pathogenesis are reviewed.

Unusual tubular calcification of a nephrostomy tract

Unusual tubular calcification occurred in the nephrostomy tract of a 30-year-old male, 6 months after percutaneous nephrostolithotomy. To our knowledge, this phenomena has not been previously reported. The main radiologic differential diagnoses are focal dystrophic calcification and vascular calcification. The etiology is unknown but may have been related to the patients' tendency to form renal calculi. The temporal sequence of events and the location of the nephrostomy catheter which correlated with the calcification suggests the correct diagnosis.

The renal parenchymal stone: a benign calcified renal mass

Five patients are described, each with a densely calcified solitary mass in a peripheral location in the kidney. There was exophytic projection of the calcification in 4 cases. Three lesions were so completely calcified as to be regarded as stones. The bulk of the lesion was calcified in the 2 other cases, in which the noncalcified portion was either avascular or hypovascular. In no case was there evidence of a soft-tissue mass extending beyond the confines of the calcification. Pathologic correlation in 1 case showed only calcification in association with some renal scarring, and in a second case demonstrated an old organized and calcified abscess. Long-term follow-up in the other 3 cases has demonstrated complete stability without evidence of tumor. All cases are believed to represent examples of calcified renal parenchymal scars, resulting from old granulomatous disease, renal abscess, or hematoma. We propose that these lesions be regarded as solitary renal parenchymal stones without malignant potential, rather than calcified masses. The significance of the findings for patient management are discussed.

Imaging of urinary tract disease. Current approaches

Current modalities and techniques used in imaging of the urinary tract offer prompt and accurate diagnoses as well as treatment in some cases. Careful planning and judgement in the choice of the imaging sequence is important in avoiding redundant or ill-advised tests. Individual tailoring will be necessary in some patients. It is hoped that with the rational use of the diagnostic tools now available and with the continued improvement in MRI technology, safe and accurate diagnoses will be expected in practically all patients with diseases of the urinary tract.