Comparative study between 1.5 and 3 Tesla multiparametric MRI systems using the PIRADS version 2 classification in the diagnosis of prostate cancer

Introduction: The 3-Tesla multiparametric MRI (mpMRI) system represents a diagnostic advance for prostate cancer. Our aim is to demonstrate that the results in 1.5-Tesla mpMRI are not inferior compared to the 3-Tesla for the correct diagnosis of prostate cancer.

Material and methods: Non-inferiority comparative cross-sectional study between fusion-guided prostate biopsy results. 344 patients with clinical suspicion of prostate cancer (elevated PSA and/or suspicious DRE) and mpMRI interpreted and verified by the same radiologists in all cases, 270 in 1.5-Tesla and 74 in 3-Tesla, with at least one lesion PIRADSv2≥ 3. Exclusion criteria were positive biopsy or previous prostate treatment. We consider malignancy as ISUP≥ 1 and significant tumor as ISUP≥ 2. We used Wilcoxon and t-student test (central tendency measures), diagnostic test (gold standard: ISUP of targeted biopsy), Chi2 test and Z-test (comparison of prevalences and 95%CI malignancy and significant tumor according to mpMRI).

Results: Median prostate volume 50cc(IQR:33.5) and PSA 6.11ng/ml(IQR:3.39). Mean age 67.4±8.1years. Number of suspi-cious lesions/patient: mpMRI 1.3 (1.5-Tesla) and 1.5 (3-Tesla). No differences were found between mpMRI (homogeneous and comparable samples). 57% (1.5-Tesla) vs 66% (3-Tesla) of targeted biopsies were malignant, and 34%vs38% were significant tumor, with no significant differences. Se, Sp, PPV and NPV for malignancy (1.5-Tesla vs 3-Tesla) were 96%vs90%, 38%vs44%, 67%vs76%, and 86%vs69%, with no significant differences.

Conclusions: There are no significant differences between 1.5-Tesla vs 3-Tesla mpMRI regarding targeted biopsy results. Not to have 3-Tesla mpMRI may not be a limitation to use 1.5-Tesla as a diagnostic test for the better diagnosis of prostate cancer.