Performances de l’IRM 3T dans la Détection de l’Extension du Cancer de la Prostate aux Vésicules Séminales

RESUME Objectif. Evaluer la performance de l’IRM 3T dans la detection de l’extension du cancer de la prostate aux vesicules seminales. Patients et methodes. Il s’agissait d’une etude retrospective realisee sur 11 mois (du 22/11/2016 au 17/10/2017) dans le service de radiologie B du CHU Gabriel Montpied de Clermont Ferrand, incluant les patients ayant eu une prostatectomie radicale pour cancer de la prostate et qui ont beneficie d’une IRM 3T. Resultats. 34 patients ont ete inclus. L’âge moyen des patients etait de 58 ans. Tous les patients presentaient un adenocarcinome. Sur les pieces de prostatectomie, 23 cancers soit 67,64% etaient localises a la base. Les pieces vesiculaires etaient representatives dans 13 cas soit 38,24%. Pour 6 patients (17,65%), une extension vesiculaire etait rapportee dont une sous la forme d’emboles endolymphatiques. Les examens IRM ont ete realises pour 17 patients (50 %) 6 semaines apres la biopsie. L’IRM etait jugee interpretable pour 22 patients (64,70%). Les signes IRM d’envahissement des vesicules seminales les plus frequents etaient les anomalies de signal T2 et les anomalies de perfusion. Le coefficient de concordance de Kappa etait de 0,76 avec p=0,0005 et 89% de paires concordantes. Conclusion. Ces resultats preliminaires sont encourageants mais necessitent d’etre confirmes avec un effectif de patients plus large. Les ecueils observes nous ont amenes a ameliorer la technique de realisation des protocoles d’IRM notamment en ce qui concerne la bonne couverture des vesicules seminales. ABSTRACT Objective. To assess the performance of 3T MRI in the detection of prostate cancer extension to the seminal vesicles. Patients and methods. This was a retrospective study carried out over 11 months (from 22/11/2016 to 17/10/2017) in the radiology department B of the CHU Gabriel Montpied in Clermont Ferrand, including patients who had undergone radical prostatectomy for prostate cancer and who benefited from 3T MRI.  Results. Thirty four (34) patients were included. Their mean age was 58 years. All patients had adenocarcinoma. On prostatectomy specimens, 23 cases (67.64%) were located at the base. Vesicular specimens were representative in 13 cases (38.24%). For 6 patients (17.65%), a vesicular extension was reported, one of which was in the form of endo lymphatic emboli. MRI examinations were performed 6 weeks after the biopsy for in 17 patients (50%). MRI was considered interpretable in 22 patients (64.70%). The most frequent signs of seminal vesicle invasion on MRI were T2 signal abnormalities and perfusion abnormalities. The concordance coefficient of Kappa was 0.76 (p=0.0005), 89% of matched pairs. Conclusion: These preliminary results are encouraging but need to be confirmed with a larger number of patients. The pitfalls observed led us to improve the technique of carrying out MRI protocols, particularly with regard to good coverage of the seminal vesicles.