Evaluation of periprostatic neurovascular fibers before and after radical prostatectomy by means of 1.5 t mri diffusion tensor imaging

To evaluate if diffusion tensor Imaging (DTI) is able to detect changes of periprostatic neurovascular fibers (PNFs) before and after radical prostatectomy (RP), and if these changes are related to post-surgical urinary incontinence and erectile dysfunction.

22 patients (mean age 62.6 years) with biopsy-proven prostate cancer underwent 1.5-T DTI before and after radical prostatectomy (RP). The number, fractional anisotropy (FA) values and length of PNFs before and after RP were compared using Student's t-test. Each patient filled out two questionnaires before and after RP, one for the evaluation of urinary continence (ICIQ-SF) and one for the evaluation of erectile function (IIEF-5). The ratios of the number, FA values and length of PNFs before and after RP (DTI B-A RATIOs) and the ratios between the scores obtained before and after RP for both ICIQ-SF and IIEF-2 (ICIQ-SF B-A RATIOs and IIEF-2 B-A RATIOs) were calculated to perform the Kendall's Tau Test between them.

There was a statistically significant decrease of the number of PNFs after RP at base, mid gland, and apex (p<0.01) and of FA values at mid gland (p<0.05), with positive statistically significant correlation between the DTI B-A RATIOs of the number of PNFs and IIEF-2 B-A RATIOs (p<0.05, ρ=0.47).

DTI was able to detect that the decrease of the number of the PNFs after RP was statistically related to the post-surgical erectile dysfunction (p< 0.05). Advances in knowledge: This work demonstrates that: - 1.5 T MRI Diffusion Tensor Imaging is able to detect the decrease of the number and of the Fractional Anisotropy of periprostatic neurovascular fibers after prostatectomy; - the decrease of the number of periprostatic neurovascular fibers after prostatectomy is related with the post-surgical erectile dysfunction; - 1.5 T MRI Diffusion Tensor Imaging has demonstrated to be a reproducible technique in detecting the changes of the periprostatic neurovascular fibers induced by radical prostatectomy (RP), with high interobserver agreement.

The British journal of radiology. 2018 Feb 01 [Epub ahead of print]

Valerio Di Paola, Adam Cybulski, Salvatore Belluardo, Francesca Cavicchioli, Riccardo Manfredi, Roberto Pozzi Mucelli

1 Università Cattolica del Sacro Cuore di Roma, Roma, Italy., 2 Università di Verona, Verona, Italy., 3 Ospedale Civile Maggiore di Borgo Trento - Verona, Italy., 4 Ospedale Sacro Cuore Don Calabria di Negrar, Negrar, Italy.