[Radio-transparent renal calculi and epithelial tumours. Contribution of ultrasound and CT scan to the diagnosis (author's transl)]. / Calculs rénaux radio-transparents et tumeurs urothéliales. Apports diagnostiques de l'échotomographie et de la tomodensitométrie.

The aetiological diagnosis of lacunae detected by urography is uncertain in 10 to 20% of cases. Uric acid calculi larger than 2 cm in diameter can be demonstrated by ultrasonography, where they show as echogenic areas with conical shadows. Computerized tomography has wider possibilities: uric acid calculi are extremely dense and clearly visible, clots are not enhanced by contrast media, and the enhancement of epithelial tumours is of the avascular type.

Visibility and thickening of the renal fascia on computed tomograms.

The renal fascia can be seen on CT scans (using appropriate window settings) in most patients except those with very little fat. CT confirms current anatomical concepts; however, contrary to the illustrations shown in the literature, it clearly demonstrates that the anterior pararenal space normally exists only at the level of the retroperitoneal organs. A lesion would distend the space. While visualization of the renal fascia on normal urograms may be an indication of renal disease, a thin renal fascia on CT scans has no pathological significance. Thickening is nonspecific: it is not pathognomonic of tumor, nor is it helpful in differentiating pancreatitis from neoplasm. On the other hand, lack of fascial thickening may be helpful in ruling out renal extension of a neighboring lesion.

Cystadenomas of the pancreas: diagnosis by computed tomography.

Three cases of benign pancreatic cystadenoma, diagnosed by computed tomography (CT), are reported. Other neoplasms with similar CT appearance are illustrated as examples of some pitfalls in the CT diagnosis of cystadenoma.

[Scanner examination of the kidney]. / Le rein en tomodensitométrie.

On the basis of a large series of documents, the authors participate in establishment of the classification of scanner appearances of urological diseases of the kidney : peripheral or parapelvic sub-capsular cysts, carcinomas and their spread, multiple tumours but of different nature in the same kidney, angiomyolipomas, polycystic disease, renal abscess, hydated cyst, non-invasive exploration of kidneys showed to be non-functioning by I.V.U., tumours of the intrarenal excretory system, lumbar trauma, long-term surveillance of the retroperitoneal space in individuals undergoing surgery for a urological malignant renoureteric tumour. The authors suggest a new chronological arrangement of investigations in the presence of a renal mass discovered by I.V.U. Scanner has its place between echotomography and renal arteriography. Investigations may be stopped at renal echotomography when this examination offers definite evidence of the fluid nature of the mass. Solid or doubtful nature of the mass necessitates the use of a scanner examination.

Computed tomography of the gastrointestinal tract: lesion recognition and pitfalls.

Abnormalities in the gastrointestinal tract will be found on computed tomography (CT) scans performed for other indications if they are carefully searched for. This potential will increase as CT is used earlier in the investigation of suspected abnormalities of the pancreas. retroperitoneum, and liver. Additionally, CT may be valuable in assessing the extent of a known primary lesion of the alimentary tract.