[Exploration of renal arteries by angio-MRI]. / Exploration des artères rénales par angio-IRM.

Major clinical challenges are involved in applications of MR-angiography for the study of renal arteries, mostly for the diagnosis of renovascular hypertension. This technique now competes with color Doppler flow sonography and spiral CT. MR angiography of the renal arteries can be performed with 2D or 3D, flight-time or phase contrast sequences. Main and co-dominant arteries are usual by visualized on all sequences, but small accessory arteries are often missed. The diagnosis of stenosis is based on the presence of an area of signal extinction. The degree of extinction depends on the degree of turbulence, the type of technique, the length of TE and spatial resolution parameters, which is why scoring of stenoses is difficult and frequently overestimated. The diagnostic performance for stenosis is between 50 and 100% for sensitivity and between 80 and 97% for specificity. Detection of distal stenoses is poor because of respiratory artifacts. Multiphase acquisitions make it possible to measure the renal blood flow on each renal artery, adding hemodynamic criteria to this diagnosis.

[Imaging of the renal transplant. Radiological methods]. / Imagerie du transplant rénal. Les méthodes radiologiques.

Ultrasound examination with morphological sonography and color flow imaging is now considered as the main technique for the follow-up of renal transplants. Morphology of the graft, and quality of perfusion can be assessed non invasively with this technique. Indications of IV pyelography decreased considerably in many centers. CT can help in characterizing intra-abdominal collections. MR will probably play a major role in the future allowing the graft itself, the perirenal space, and the intrarenal vessels to be studied by means of MR-angiography techniques.

External iliac vein stenosis after segmental pancreatic transplantation: treatment by percutaneous endoprosthesis.

A stenosis of the iliac vein secondary to a fluid collection in a pancreas transplant was identified by color Doppler flow sonography. The pancreatic venous drainage was reversed to the contralateral iliac veins via venous collaterals. After two unsuccessful angioplasties of the vein stenosis, a Wallstent was positioned above the venous anastomosis, and has remained patent for 8 months. The pancreatic venous drainage became normal after the procedure.

Radioclinical problems raised by megalodolichobasilar artery. 17 cases and a review of the literature.

Megalodolichobasilar artery (MDBA) is a vascular abnormality characterized by a regular increase in caliber and lengthening of the vertebrobasilar system (VBS), with varying degrees of displacement. Several physiopathological theories have been put forward. Clinically, MDBA may compress the cranial nerves and may be responsible for ischaemic accidents of the brain stem, hydrocephalus or mass syndrome. The radiological images may be misleading. The diagnosis of MDBA should be considered on the basis of CT findings, and its should be confirmed by vertebral arteriography at the slightest doubt.

[Retroperitoneal teratoma in children. Apropos of 2 cases]. / Les tératomes rétropéritonéaux de l'enfant. A propos de deux cas.

Retroperitoneal teratoma is infrequent (5% of all teratomas). The diagnosis is usually made within the first year of life. Two cases are reported. Case n. 1 is typical of mature benign teratoma with teeth, fat and water densities visible on the plain film of the abdomen. Cases n. 2 a malignant partly ossified immature teratoma. The ossification is in continuity of a congenital block of vertebral bodies L2 and L3; this association has not been reported in the literature. CT in both cases was contributive for delineation of the tumor but did not help to answer the question of malignancy or not; foeto-protein remains the only test to do that discrimination.

[External epiphysiolysis with caput valga. Apropos of 2 cases]. / Epiphysiolyse externe avec "caput valga". A propos de 2 observations.

External epiphysiolysis with valgus slip of the femoral epiphysis is rare. The authors report two such chronic cases, one unilateral and the other bilateral. This disorder complicates a coxa valga with a reversed cephalic growth plate, downward and externally. This coxa valga which appears constitutional is sometimes associated with an increase in femoral antetorsion. Treatment is the same as classical varus slip of the femoral epiphysis.