Resumo

CANALS L, Mauricio et al. VALUE OF DIFFUSION-WEIGHTED SEQUENCES IN THE STUDY OF PROSTATE CANCER IN PATIENTS WITH INCREASED PROSTATE SPECIFIC ANTIGEN LEVELS. Rev. chil. radiol. [online]. 2010, vol.16, n.3, pp. 121-127. ISSN 0717-9308.  doi: 10.4067/S0717-93082010000300005.

In prostatic carcinoma, the glandular architecture is replaced by cancer cells producing barriers to water motion, anomaly that can be studied through diffusion-enhanced MRI technique. To assess the contribution of these sequences in the prostate cancer exploration, we conducted a descriptive and inferential study using diffusion-enhanced MRI technique in 26 patients with abnormal digital rectal examination (DRE) and increased prostate specific antigen (PSA) values. We analyzed sensitivity, specificity and ROC curves based on apparent diffusion coefficient (ADC). Seven out of 14 biopsies were positive in patients undergoing prostate biopsy. When applying ADC <1000 _m2/se, high sensitivity with low specificity levels, as well as moderate predictive values were obtained. By incorporating T2-weighted images, improved diagnostic accuracy, specificity and predictive values were achieved. When comparing ADC values in tissues with and without cancer, average and minimum ADC appeared to exhibit different values. ROC curves depicted increased and significant values, suggesting cutoff values of 1059iirrf/s and 969/jm²/s for healthy and malignant tissues, respectively; LR (+) for cut-off value: 6.97 and 5.23, respectively. Our results enable us to propose that improved diagnostic outcomes are attained through combined interpretation of T2-weighted images and diffusion-weighted sequences and that the ADC permits discrimination between normal and malignant tissues. Therefore, we strongly support that these criteria should be taken into account when performing prostate explorations.

Palavras-chave : Diffusion; Prostate cancer; MRI.