Presentation Authors: Patrick Blaza*, Jason Letran, German Jose Albano, Manila, Philippines
Introduction: We compared the Biparametric MRI (BP-MRI) to the standard Multiparametric MRI (MP-MRI) with Dynamic Contrast Enhanced (DCE) sequence in determining the Prostate Imaging - Data and Recording System (PI-RADS) score in patients with suspected prostate cancer. If there is no significant difference in the results, a Biparametric study may reliably guide our decision to do a prostate biopsy without the added cost and potential adverse effects of the intravenous (IV) contrast agents.
Methods: We performed a cross-sectional study comparing the final PI-RADS scores taken using only T2-Weighted Image (T2W) and Diffusion-Weighted Image (DWI) sequences and compared them to the PI-RADS scores taken using T2W, DWI and DCE sequences, the standard multiparametric protocol. Agreement between the two groups was assessed using Bland-Altman plots, while Interclass Correlation Coefficient (ICC) was utilized to assess reliability.
Results: A total of 803 prostate lesions were identified in 490 patients. Of these lesions, 442 (55%) were PI-RADS 3, 216 (27%) were PI-RADS 4, and 132 (16%) were PI-RADS 5. The presence of contrast enhancement in the DCE sequence upgraded 18% of PI-RADS 3 lesions to PI-RADS 4, and 1% of PI-RADS 4 lesions to PI-RADS 5. With exclusion of the DCE sequence, 431 (97.5%) of the 442 PI-RADS 3 lesions remained unchanged, and only 5 (1.1%) were downgraded to PI-RADS 2, while 92 (42%) of the 216 PI-RADS 4 lesions were downgraded to PI-RADS 3. Bland-Altman Plots showed good agreement with a mean difference between the two methods of -0.12 (-0.89 to 0.64). ICC among PI-RADS 3, 4, and 5 was excellent at 0.89 (0.85 â€“ 0.91).
Conclusions: The exclusion of the DCE sequence had minimal influence in distinguishing lesions as clinically significant (PI-RADS 3-5) or indolent (PI-RADS 1-2), with only a 1.1% incidence of downgrading from PI-RADS 3 to PI-RADS 2. We conclude that a Biparametric MRI of the prostate is a reliable tool in the selection of patients for biopsy.