[Diffusion-weighted MR imaging of the kidney]. / Apport de l'IRM de diffusion en pathologie rénale.

After being first used for liver imaging, diffusion-weighted imaging of the kidney is in development. The kidney is the only anisotropic organ in the abdomen. It is a complex organ, with different types of flow, that is the subject of multiple research projects. Diffusion-weighted imaging is very sensitive for the detection of tumors, especially small ones. It also facilitates lesion characterization with the help of ADC values. Diffusion restriction indicates hypercellularity, which suggests malignancy. Diffusion-weighted imaging is currently available on clinical scanners. Characterization of different types of collections is possible. The characterization of nephropathies remains investigational.

[The role of diffusion 3-Tesla MRI in detecting prostate cancer before needle biopsy: multiparametric study of 111 patients]. / Rôle de l'IRM de diffusion pour la détection du cancer de la prostate avant ponction biopsie: étude multiparamétrique de 111 patients à 3 Tesla.

AIM: Evaluate diffusion MRI in the multiparametric assessment of prostate cancer before needle biopsy. MATERIALS AND METHODS: One hundred eleven patients with suspected prostate cancer (mean age: 63 years old, median PSA: 7 ng/mL) were examined before undergoing needle biopsy (59 patients with a history of a negative biopsy and 52 without a history of biopsy). A diffusion sequence type SS SE-EPI (TR/TE: 5357/58, fEPI: 73, b 0 and 1000 s/mm², axial) with a qualitative analysis of the ADC map was performed in addition to T2 and T1 gadolinium enhanced sequences on 3 T MRI with an endorectal coil. The histological correlations were obtained by ultrasound guided needle biopsy (85 patients) or radical prostatectomy (26 patients). RESULTS: The correlation of the results of the diffusion sequence in the series of the 111 patients and the biopsies of the entire prostate or the hemiprostate had a sensitivity of: 92%, 77%; a specificity of: 55%, 70%; a positive predictive value of: 77%, 62%; a negative predictive value of: 84%, 80% and an efficacy of 78%, 75% respectively. The agreement of the three sequences had a specificity of 84.3%. CONCLUSION: The sensitivity of diffusion MRI is high for the detection of cancer of the prostate. Specificity of sequences is good. The results of simple visual assessment of the ADC map are good.