MRI OF CANCERS OF THE PROSTATE WITH T1-WE IGHTED SEQUENCES USING FAT-SUPPRESSION AND GADOLINIUM INJECTIONS

The assessment of tumor extension in 20 patients with cancers of the p rostate at a clinical stade A or B included MRI with a body coil befor e prostatectomy. Transverse and coronal T1-weighted sections with inje ctions of gadopentate dimeglumine (gadolinium) and fat suppression wer e systematically taken to assess the vascularity of the various region s of the prostate and of the cancer, as well as the merits of such seq uences for the assessment of extension. The normal, poorly vascularize d peripheral area is only slightly enhanced by injection, while the tr ansition area, which is most often hyperplastic in the age group studi ed, enhances heterogeneously with contrast. All cancers enhance after injection. In the assessment of extension, the major merit of gadolini um is that it allows exploration both of the vesiculodeferential junct ion on coronal sections and of the structure of the seminal vesicles. Thus a normal junction allows ruling out macroscopic invasion of the v esicles. In addition, gadolinium allows correcting false positive MRI findings when the areolar structure of the vesicles is preserved. Gado linium does not provide additional evidence of extension through the c apsule in comparison with T2-weighted sequences. On a whole, in our se ries, MRI with a body coil, associated T2-weighted sequences and T1-we ighted sequences after gadolinium injection and fat suppression, has 5 8% sensitivity and 100% specificity for the diagnosis of stage C cance rs.