Different types of nerve fibers demonstrate distribution variations. When linked to possible functional aspects of the different nerve types, this morphologic evidence may be of importance to further protect function after radical prostatectomy. To our knowledge this is the first time that DTI confirmed reported histological findings in nerve sparing radical prostatectomies. DTI could be used as an important tool to correlate nerves-to-tumor for better pre-operative planning and incorporate imaging into the treatment. This article is protected by copyright. All rights reserved.

Objectives: In spinal cord injury (SCI), the primary mechanical injury is followed by secondary sequelae that develop over the subsequent months and manifests in biochemical, functional, and microstructural alterations, at the site of direct injury but also in the spinal cord tissue above and below the actual lesion site. Noninvasive magnetic resonance spectroscopy (MRS) can be used to assess biochemical modulation occurring in the secondary injury phase, in addition to and supporting conventional MRI, and might help predict and improve patient outcome. In this article, we aimed to examine the metabolic levels in the pons of subacute SCI by means of in vivo proton MRS at 3 T and explore the association to clinical scores. Materials and Methods: In this prospective study, between November 2015 and February 2018, single-voxel short-echo MRS data were acquired in healthy controls and in SCI subjects in the pons once during rehabilitation. Besides the single-point MRS examination, in addition, in participants with SCI, the clinical status (ie, motor, light touch, and pinprick scores) was assessed twice: (1) around the MRS session (approximately 10 weeks postinjury) and (2) before discharge (at approximately 9 months postinjury). The group differences were assessed with Kruskal-Wallis test, the post hoc comparison was assessed with Wilcoxon rank sum test, and the clinical correlations were conducted with Spearman rank correlation test. Bayes factor calculations completed the statistical part providing relevant evidence values. Results: Twenty healthy controls (median age, 50 years; interquartile range, 41-55 years; 18 men) and 18 subjects with traumatic SCI (median age, 50 years; interquartile range, 32-58 years; 16 men) are included. Group comparison showed an increase of total N-acetylaspartate and combined glutamate and glutamine levels in complete SCI and a reduction of total creatine in incomplete paraplegic SCI. The proton MRS-based glutathione levels at baseline correlate to the motor score improvement during rehabilitation in incomplete subacute SCI. Conclusions: This exploratory study showed an association of the metabolite concentration of glutathione in the pons assessed at approximately 10 weeks after injury with the improvements of the motor score during the rehabilitation. Pontine glutathione levels in subjects with traumatic subacute incomplete SCI acquired remote from the injury site correlate to clinical score and might therefore be beneficial in the rehabilitation assessments.

INTRODUCTION AND OBJECTIVES: The lower urinary tract (LUT) is innervated by a network of nerve fibers from S2 to S4 and from the pudendal nerve. Neurogenic disorders (e.g. SCI, Multiple sclerosis) or surgery in the pelvis (e.g. radical prostatectomy) can affect the integrity of this neural circuit, leading to LUT dysfunction with incontinence or erectile dysfunction, impairing the patients' quality of life. Diffusion tensor imaging (DTI) offers a promising tool to investigate the neural circuit in vivo. Aim of the study was to evaluate if DTI imaging of the LUT is feasible.METHODS: In a prospective pilot study we used DTI fiber tracking to image the innervation of the LUT in 5 healthy volunteers and 4 patients with neurogenic LUT dysfunction. We used an adapted algorithm as mentioned by van der Jagt and Haakma (Neuroimage 2012, J Urol 2014). All subjects were examined with a 3.0 Tesla MR, which was performed from L5 to the pelvic floor. Total scanning time was 25 minutes, 2400 images/subject, voxel size 3x3x3 mm.RESULTS: In 8/9 subjects, DTI fiber tracking of the LUT neuronal network was feasible. In all healthy volunteers (2 female, 3 male, mean age 44.5 years) and in the four patients ( 4 male, mean age 43.7 years) visualization of the sacral roots and the innervation of the bladder and the prostate (male patients) was possible. A a high innervation density was depicted. Beside the vascular nerve bundle, the prostate is also innervated by a ventral network with connections to the bladder neck and the penile nerve bundle.CONCLUSIONS: LUT innervation in vivo with DTI fiber tracking is feasible. Our preliminary results indicate that this technique is promising for further assessment of LUT dysfunctions.

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