[MRI and prostatic cancer: measurements of kinetic perfusion parameters of gadolinium with a computerized-aided diagnostic tool (CAD)]. / IRM et cancer prostatique: mesure de la cinétique du gadolinium avec un système CAD.

OBJECTIVES: To assess with a CAD in the peripheral (ZP) and transitional (ZT) zones the areas with modifications of the kinetic parameter Kep (ratio of exchanges between vascular compartment and extravascular extracellular spaces) in prostatic cancers with DCE MRI before radical prostatectomy. METHODS: Forty-two consecutive patients (mean age 67 years, mean PSA: 8.9 ng/ml) with a prostatic cancer proved after a set of 12 biopsies underwent, before radical prostatectomy, a dynamic MRI (1.5T) with a surface coil after injection of gadolinium. We look with a CAD for foci of voxels with an abnormal Kep in ZP and/or in ZT. Foci of abnormal voxels computerized were compared with histological results of radical prostatectomies: prostates were shared in 12 sectors (six peripheral and six central) and a total of 504 sectors were studied. The links between prostatic capsule and foci of voxels with elevated Kep were systematically evaluated. The location and the local extension of the various cancerous foci were estimated. A comparison with the results of the T2W and T1 DCE MRI sequences without use of the CAD was made. RESULTS: Eighty-eight percent of investigated patients revealed at least a cancerous focus associated with a group of pathological voxels. Hundred and seventy-eight of the 504 investigated prostatic sectors revealed a cancerous lesion after radical prostatectomy (RP) and 116 a focus of voxels with a pathological Kep being linked to 71 isolated lesions, some of them filling several sectors (47 peripheral and 24 transitional). The automatic research with the software of foci of voxels with a parameter Kep more than 2,2 per minute to detect a cancerous lesion had a sensitivity by sector less than the reading without CAD (69% in ZP and 58% in ZT against respectively, 85 and 66% (p<0.01) but seemed more specific: 98% in PZ and 95% in ZT against respectively, 80 and 82% (p<0.01). After RP, 16 cancers were classified Pt2, 10 Pt2R+ and 16 Pt3. The CAD had a better accuracy (74%) than T2W MRI (60%) to look for an extracapsular extension (EPE) or a risk of positive margins: 86% of extraprostatic extension and 60% of positive margins were near a focus of pathological voxels. CONCLUSIONS: CAD allowed a computerized qualitative and quantitative study of DCE MRI. It identified and localized with a good specificity the significant foci. A focus of voxels with elevated Kep against the capsule increased significantly the risk of an extraprostatic extension or a positive margin after radical prostatectomy.

[Power Doppler and 3D vascular sonography of intraprostatic blood supply: assessment criteria and value for the diagnostic and clinical staging of prostatic cancer]. / Vascularisation intra prostatique en imagerie Doppler puissance et vasculaire 3D: critères d'analyse et intérêt dans l'établissement du diagnostic et du stade évolutif des cancers.

OBJECTIVES: To compare the value of Power Doppler Sonography (PDS) and B mode sonography in the diagnosis of prostate cancer and to assess the value of PDS to assess cell differentiation as a function of the degree of blood supply and to specify capsular effraction of the cancer. PATIENTS: 133 patients, divided into 2 groups, were investigated: one group consisted of 41 patients with no suspicion of cancer (15 control subjects and 26 patients with acute prostatitis) and a second group consisted of 92 patient with suspected cancer (PSA > 4 ng/ml). METHODS: Power Doppler sonography with 3D reconstruction was used to calculate a graduated blood supply index from 1 to 3 for nodules of the peripheral zone. Three types of blood supply (A: regular avascular capsule, B: irregular avascular capsule, C: vessels crossing the capsule) were described as a function of the presumed stage of cancer (A: intraprostatic, B: undetermined, C: extraprostatic). Comparison with histology was performed on randomized biopsies (92 cases) and radical prostatectomy specimens (21 cases). RESULTS: A cancer was diagnosed in 57 of the 92 patients (62%) with suspected cancer. The overall sensitivity of PDS in the initial diagnosis of prostatic cancer was 94.7%, and its specificity was 77.1% (versus 93% and 42.8% for sonography alone, respectively). For a prevalence between 0.4 and 0.9, the PPV ranged from 73.4% to 97.4% and the NPV ranged from 95.6% to 62% (p = 0.02). The correlation between tumour blood supply and Gleason score showed that 20/40 tumours (50%) with a Gleason score > or = 7 had a blood supply index of 3 versus 6/17 (35%) of tumours with a Gleason score < 7 (r = 0.283, p = 0.033). The 3 vascular types, A, B, C, were evaluated prospectively in the detection of capsular effraction. Capsular effraction was detected in one of the 8 cases of type A cancer and in 6 of the 8 cases (75%) of type C cancer. CONCLUSION: PDS improves the reliability of sonography in the diagnosis and staging of prostate cancer. There is a correlation between tumour blood supply and Gleason score.

[Lymphographic and x-ray computed tomographic determination of criteria for normality of the transverse diameter of retroperitoneal lymph nodes]. / Détermination lymphographique et scanographique des critères de normalité de diamètre transversal des ganglions rétropéritonéaux.

Evaluation of ganglionic extension in malignant processes rely widely on ultrasound and CT. However the information yielded by those procedures regarding the ganglionic structure is poor. What is appreciated is the size of ganglia, that is presence or absence of adenomegaly. A CT study of subjects in which lymphography did not reveal structural or size changes enables one to specify the following criteria of normality: The transverse diameter of abdominal lymph nodes should not exceed 1,5 cm. The product: transverse diameter X antero posterior diameter should not exceed 2.