Use of 3D T2-Weighted MR Sequences for the Assessment of Neurovascular Bundle Changes after Nerve-Sparing Radical Retropubic Prostatectomy (RRP): A Potential Diagnostic Tool for Optimal Management of Erectile Dysfunction after RRP

Abstract

Erectile dysfunction (ED) is one of the complications after radical retropubic prostatectomy (RRP), and recovery of erectile function is quantitatively related to the preservation of the neurovascular bundles (NVBs). The aim of our study was to assess, in patients submitted to a nerve-sparing RRP, the capability of a dedicated 3D isotropic magnetic resonance imaging (MRI) T2-weighted sequence in the depiction of postsurgical changes of NVB formation. Fifty-three consecutive patients underwent a bilateral nerve-sparing RRP. Two postoperative magnetic resonance (MR) examinations and International Index of Erectile Function Five-Item (IIEF-5) questionnaire were carried out at 6 and 12 months. Morphological imaging of the postprostatectomy fossa was performed by first acquiring turbo spin echo T2-weighted sequences in the axial and coronal planes and then with 3D T2-weighted isotropic sequence on axial plane. Image findings were scored using a relative 5-point classification (0 = normal; I = mild; II = mild to moderate; III = moderate; IV = severe alterations) and correlated with postoperative IIEF-5 score questionnaire. The degree of association between the alteration score values obtained by postoperative MR morphologic evaluation for MR sequence and IIEF-5 score. Image interpretation was performed by two radiologists, that scoring MR alterations by the use of axial and multiplanar reconstruction 3D T2 isotropic sequence. The radiologists placed 43.30% of patients in class 0 (23/53 normal or quite normal), 32.00% in class I (17/53 mild), 11.40% in class II (6/53 mild to moderate), 7.50% in class III (4/53 moderate), and 5.70% in class IV (3/53 severe). In all cases, the correlation and regression analyses between the 3D T2 isotropic sequence and IIEF-5 score, resulted in higher coefficient values (rho = 0.45; P = 0.0010). The MRI protocol and NVB change classification score proposed in this study would represent an additional tool in the postoperative phase of those patients with ED.