Extended periprostatic nerve distributions on the prostate surface confirmed using diffusion tensor imaging

To perform a descriptive microscopic study of prostatectomy specimens from 19 patients which anatomically characterizes the distributions of periprostatic nerve qualities, and to visualize these using diffusion tensor imaging (DTI).

Serial whole-mounted sections were stained for cholinergic (neuronal nitric oxide synthase), adrenergic (tyrosine hydroxylase) and sensory (calcitonin gene-related peptide) nerves. Extracapsular stained nerves were counted by prostate surface sector, and classified by diameter. Stain-related relative density was calculated, and distribution patterns were evaluated. To better visualize the reported neuronal structures and independently confirm our findings, nerve concordance in five male volunteers was investigated using a 3-Tesla magnetic resonance imaging-DTI system.

At the base, cholinergic nerves were distributed from the anterolateral to posterior sectors, continuing posterolaterally (mid-section) into the posterolateral-posterior sector toward the apex. Adrenergic nerves were distributed across the anterolateral-posterior sectors at the base, with the course narrowing to the posterolateral-posterior sectors at the mid- and apical levels. Sensory fibres were found posterolaterally posteriorly at the base, continuing posterolaterally over the mid- and apical levels. Although it was not possible to determine the different nerve qualities, DTI confirmed histological findings from the base to the apex.

Different types of nerve fibres were found to vary in distribution. When linked to possible functional aspects of the different nerve types, this morphological evidence may be of importance to further protect function after radical prostatectomy (RP). To our knowledge, this is the first time that DTI has confirmed reported histological findings in nerve-sparing RPs. DTI could be an important tool with which to correlate nerves to tumour for better preoperative planning and to incorporate imaging into treatment.