In vivo 3D neuroanatomical evaluation of periprostatic nerve plexus with 3T-MR Diffusion Tensor Imaging. Eur J Radiol. 2013;82:1677-1682. [PMID: 23773553 DOI: 10.1016/j.ejrad.2013.05.013]

What the urologist needs to know before radical prostatectomy: MRI effective support to pre-surgery planning

BACKGROUND

Radical prostatectomy (RP) is recommended in case of localized or locally advanced prostate cancer (PCa), but it can lead to side effects, including urinary incontinence (UI) and erectile dysfunction (ED). Magnetic resonance imaging (MRI) is recommended for PCa diagnosis and staging, but it can also improve preoperative risk-stratification.

PURPOSE

This nonsystematic review aims to provide an overview on factors involved in RP side effects, highlighting anatomical and pathological aspects that could be included in a structured report.

EVIDENCE SYNTHESIS

Considering UI evaluation, MR can investigate membranous urethra length (MUL), prostate volume, the urethral sphincter complex, and the presence of prostate median lobe. Longer MUL measurement based on MRI is linked to a higher likelihood of achieving continence restoration. For ED assessment, MRI and diffusion tensor imaging identify the neurovascular bundle and they can aid in surgery planning. Finally, MRI can precisely describe extra-prostatic extension, prostate apex characteristics and lymph-node involvement, providing valuable preoperative information for PCa treatment.

CONCLUSIONS

Anatomical principals structures involved in RP side effects can be assessed with MR. A standardized MR report detailing these structures could assist urologists in planning optimal and tailored surgical techniques, reducing complications, and improving patients' care.

Perineural Invasion and Spread in Common Abdominopelvic Diseases: Imaging Diagnosis and Clinical Significance

Malignancies and other diseases may spread by multiple pathways, including direct extension, hematogenous spread, or via lymphatic vessels. A less-well-understood route is the peripheral nervous system, which is known as perineural spread (PNS). In addition to accounting for pain and other neurologic symptoms, PNS affects both disease prognosis and management. Although PNS is commonly discussed in relation to head and neck tumors, there is emerging data regarding PNS in abdominopelvic malignancies and other conditions such as endometriosis. Due to improved contrast and spatial resolution, perineural invasion, a finding heretofore diagnosed only at pathologic examination, can be detected at CT, MRI, and PET/CT. PNS most commonly manifests as abnormal soft-tissue attenuation extending along neural structures, and diagnosis of it is aided by optimizing imaging parameters, understanding pertinent anatomy, and becoming familiar with the typical neural pathways of spread that largely depend on the disease type and location. In the abdomen, the celiac plexus is a central structure that innervates the major abdominal organs and is the principal route of PNS in patients with pancreatic and biliary carcinomas. In the pelvis, the lumbosacral plexus and inferior hypogastric plexus are the central structures and principal routes of PNS in patients with pelvic malignancies. Although the imaging findings of PNS may be subtle, a radiologic diagnosis can have a substantial effect on patient care. Knowledge of anatomy and known routes of PNS and optimizing imaging parameters is of utmost importance in providing key information for prognosis and treatment planning. © RSNA, 2023 Supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. Quiz questions for this article are available through the Online Learning Center.

Impact of Pelvic Anatomical Changes Caused by Radical Prostatectomy

Simple Summary

After radical prostatectomy, the pelvic anatomy is altered such that the postoperative structure differs from the preoperative one, resulting in a variety of complications. In this review, the complications and mechanisms of pelvic anatomical changes associated with radical prostatectomy, as well as countermeasures, are outlined. An analysis of the anatomical mechanisms that cause complications after radical prostatectomy using imaging and other modalities is in progress. In addition, many surgical techniques that ensure the prevention of postoperative complications have been reported, and their usefulness has been evaluated. The preservation of as much periprostatic tissue and periprostatic structures as possible may lead to favorable postoperative functions, as long as the cancer condition permits.

Abstract

During radical prostatectomy, the prostate is removed along with the seminal vesicles, and the urinary tract is reconstructed by dropping the bladder onto the pelvic floor and suturing the bladder and urethra together. This process causes damage to the pelvic floor and postoperative complications due to the anatomical changes in the pelvic floor caused by the vesicourethral anastomosis. Urinary incontinence and erectile dysfunction are major complications that impair patients’ quality of life after radical prostatectomy. In addition, the shortening of the penis and the increased prevalence of inguinal hernia have been reported. Since these postoperative complications subsequently affect patients’ quality of life, their reduction is a matter of great interest, and procedural innovations such as nerve-sparing techniques, Retzius space preservation, and inguinal hernia prophylaxis have been developed. It is clear that nerve sparing is useful for preserving the erectile function, and nerve sparing, urethral length preservation, and Retzius sparing are useful for urinary continence. The evaluation of pre- and postoperative imaging to observe changes in pelvic anatomy is also beginning to clarify why these techniques are useful. Changes in pelvic anatomy after radical prostatectomy are inevitable and, therefore, postoperative complications cannot be completely eliminated; however, preserving as much of the tissue and structure around the prostate as possible, to the extent that prostate cancer control is not compromised, may help reduce the prevalence of postoperative complications.

Technical advances in nerve-sparing and continence preservation

PURPOSE OF REVIEW

Urinary incontinence and erectile dysfunction are common after radical prostatectomy. These side effects greatly impact patients' quality of life. Therefore, surgical techniques and technology tools are constantly being developed to optimize trifecta outcomes. Here we focus on advances in nerve-sparing (NS) and continence preservation.

RECENT FINDINGS

New surgical techniques dedicated to preservation rather than reconstruction have been developed to improve urinary continence (UC) and NS. On the other hand, intraoperative assessment of prostatic and periprostatic structures has shown promising outcomes toward NS whereas avoiding omission of extracapsular extension (ECE). Likewise, neural regeneration strategies are under research to improve return of erectile function and UC.

SUMMARY

Superb outcomes after Robot-Assisted Radical Prostatectomy require a proper balance between NS and risk of ECE. Detailed anatomic knowledge together with an accurate surgical planning are cornerstone for tailoring the approach in each case.

Correlation between FA and ADC, number and length of the periprostatic neurovascular fibers

PURPOSE

Our aim was to explore the relation between FA and ADC, number and length of the periprostatic neurovascular fibers (PNF) by means of 1.5 T Diffusion Tensor Imaging (DTI) imaging through a multivariate linear regression analysis model.

METHODS

For this retrospective study, 56 patients (mean age 63.5 years), who underwent 1.5-T prostate MRI, including DTI, were enrolled between October 2014 and December 2018. Multivariate regression analysis was performed to evaluate the statistically significant correlation between FA values (dependent variable) and ADC, the number and the length of PNF (independent variables), if p-value <0.05. A value of 0.5 indicated poor agreement; 0.5-0.75, moderate agreement; 0.75-0.9, good agreement; 0.61-0.80, good agreement; and 0.9-1.00, excellent agreement.

RESULTS

The overall fit of the multivariate regression model was excellent, with R² value of 0.9445 (R² adjusted 0.9412; p < 0.0001). Multivariate linear regression analysis showed a statistically significant correlation (p < 0.05) for all the three independent variables. The r partial value was -0.9612 for ADC values (p < 0.0001), suggesting a strong negative correlation, 0.4317 for the number of fiber tracts (p < 0.001), suggesting a moderate positive correlation, and -0.306 for the length of the fiber tracts (p < 0.05), suggesting a weak negative correlation.

CONCLUSIONS

Our multivariate linear regression model has demonstrated a statistically significant correlation between FA values of PNF with other DTI parameters, in particular with ADC.

Selection of patients for nerve sparing surgery in robot‐assisted radical prostatectomy

Context

Robot‐assisted radical prostatectomy (RARP) has become the standard surgical procedure for localized prostate‐cancer (PCa). Nerve‐sparing surgery (NSS) during RARP has been associated with improved erectile function and continence rates after surgery. However, it remains unclear what are the most appropriate indications for NSS.

Objective

The objective of this study is to systematically review the available parameters for selection of patients for NSS. The weight of different clinical variables, multiparametric magnetic‐resonance‐imaging (mpMRI) findings, and the impact of multiparametric‐nomograms in the decision‐making process on (side‐specific) NSS were assessed.

Evidence acquisition

This systematic review searched relevant databases and included studies performed from January 2000 until December 2020 and recruited a total of 15 840 PCa patients. Studies were assessed that defined criteria for (side‐specific) NSS and associated them with oncological safety and/or functional outcomes. Risk of bias assessment was performed.

Evidence synthesis

Nineteen articles were eligible for full‐text review. NSS is primarily recommended in men with adequate erectile function, and with low‐risk of extracapsular extension (ECE) on the side‐of NSS. Separate clinical and radiological variables have low accuracy for predicting ECE, whereas nomograms optimize the risk‐stratification and decision‐making process to perform or to refrain from NSS when oncological safety (organ‐confined disease, PSM rates) and functional outcomes (erectile function and continence rates) were assessed.

Conclusions

Consensus exists that patients who are at high risk of ECE should refrain from NSS. Several multiparametric preoperative nomograms were developed to predict ECE with increased accuracy compared with single clinical, pathological, or radiological variables, but controversy exists on risk thresholds and decision rules on a conservative versus a less‐conservative surgical approach. An individual clinical judgment on the possibilities of NSS set against the risks of ECE is warranted.

Patient summary

NSS is aimed at sparing the nerves responsible for erection. NSS may lead to unfavorable tumor control if the risk of capsule penetration is high. Nomograms predicting extraprostatic tumor‐growth are probably most helpful.

Depiction of periprostatic nerve fibers by means of 1.5 T diffusion tensor imaging

PURPOSE

The knowledge of periprostatic nerve fiber (pNF) is still incomplete by means of conventional MRI. The purpose of our study was to demonstrate if DTI imaging is able to depict anatomical features of pNF.

METHODS

For this retrospective study, fifty-six patients (mean age 63.5 years), who underwent 1.5-T prostate MRI, including 32 directions DTI, were enrolled between October 2014 and December 2018. ANOVA test and Student's t-test were performed between the mean values of the number, FA values, and fiber length of pNF between base and mid-gland, mid-gland and apex, base and apex, right and left side, and anterior and posterior face of the prostate. A qualitative analysis was performed to detect the main orientation of pNF through a colorimetric 3D tractographic reconstruction.

RESULTS

The number of pNF showed a decrease from the base (322) to mid-gland (248) and apex (75) (p < 0.05). The FA values were higher at base and mid-gland (0.435 and 0.456) compared to the apex (0.313) (p < 0.05). The length of pNF was higher at apex (13.4 mm) compared to base (11.5 mm) and mid-gland (11.7 mm) (p < 0.05). The number of pNF was higher on the posterior face compared to the anterior face at base (186 vs 137), (p < 0.001). The FA values were higher on the posterior face compared to the anterior face at base (0.452 vs 0.417), mid-gland (0.483 vs 0.429), and apex (0.42 vs 0.382), (p < 0.05). The length of the pNF was higher in the posterior (14.7 mm) than in the anterior face (12 mm) at apex (p < 0.001). The main orientation of pNF was longitudinal in all patients (56/56, 100%).

CONCLUSIONS

DTI imaging has been demonstrated able to depict anatomical features of pNF.

Mapping the rest of the human connectome: Atlasing the spinal cord and peripheral nervous system

The emergence of diffusion, structural, and functional neuroimaging methods has enabled major multi-site efforts to map the human connectome, which has heretofore been defined as containing all neural connections in the central nervous system (CNS). However, these efforts are not structured to examine the richness and complexity of the peripheral nervous system (PNS), which arguably forms the (neglected) rest of the connectome. Despite increasing interest in an atlas of the spinal cord (SC) and PNS which is simultaneously stereotactic, interactive, electronically dissectible, scalable, population-based and deformable, little attention has thus far been devoted to this task of critical importance. Nevertheless, the atlasing of these complete neural structures is essential for neurosurgical planning, neurological localization, and for mapping those components of the human connectome located outside of the CNS. Here we recommend a modification to the definition of the human connectome to include the SC and PNS, and argue for the creation of an inclusive atlas to complement current efforts to map the brain's human connectome, to enhance clinical education, and to assist progress in neuroscience research. In addition to providing a critical overview of existing neuroimaging techniques, image processing methodologies and algorithmic advances which can be combined for the creation of a full connectome atlas, we outline a blueprint for ultimately mapping the entire human nervous system and, thereby, for filling a critical gap in our scientific knowledge of neural connectivity.

Characterization of prostate cancer using diffusion tensor imaging: A new perspective

PURPOSE

This study is aimed at evaluating the potential role of quantitative magnetic resonance diffusion tensor imaging (DTI) and tractography parameters in the detection and characterization of peripheral zone prostate cancer with a particular attention for fiber tract density.

MATERIALS AND METHODS

DTI was acquired from eleven high risk, transrectal ultrasound (TRUS)-guided biopsy proven prostate cancers with perineural invasion (histological Gleason score ≥ 7) on a 3 T magnet. Twenty parameters derived from DTI were quantified in cancer and healthy regions of the prostate. In addition, fiber tract density in normal versus cancer tissues was also calculated using DTI tractography. Support vector machine with a radial basis function kernel and area under receiver operator characteristic (ROC) were used to describe and compare the diagnostic performance of combined fractional anisotropy (FA) and mean diffusivity (MD) and other statistically significant DTI parameters. Spearman correlation analysis between DTI parameters and Gleason scores was conducted.

RESULTS

Eighteen DTI parameters yielded statistically significant differences between cancer and healthy regions (p-value < 0.05). The ROC curve of all statistically significant DTI parameters between cancer and healthy regions was higher than the area under ROC curve using FA + MD alone (95% confidence interval = 0.988, range = 0.975-1.00) vs (95% confidence interval = 0.935, range = 0.898-0.999), respectively (p-value < 0.05). Fiber tract density was also found to be higher in cancer than in healthy tissues (+38.22%, p-value = 0.010) and may be related to the increase in nerve and vascular density reported in prostate cancer. The linear and relative anisotropy were highly correlated with Gleason score (Spearman correlation factor r = 0.655, p-value = 0.001 and r = 0.667, p-value < 0.001, respectively).

CONCLUSIONS

DTI has the potential to provide imaging biomarkers in the detection and characterization of prostate cancer. Novel quantitative parameters derived from DTI and DTI tractography, including fiber tract density, support the use of DTI in the assessment of high grade prostate cancer.

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

OBJECTIVE

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.

METHODS

22 patients (mean age 62.6 years) with biopsy-proven prostate cancer underwent 1.5 T DTI before and after 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 τ-test between them.

RESULTS

There was a statistically significant decrease of the number of PNFs after RP at base, midgland, and apex (p < 0.01) and of FA values at midgland (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).

CONCLUSION

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) 1.5 T MRI DTI is able to detect the decrease of the number and of the FA of PNFs after prostatectomy; (2) the decrease of the number of PNFs after prostatectomy is related with the post-surgical erectile dysfunction; (3) 1.5 T MRI DTI has demonstrated to be a reproducible technique in detecting the changes of the PNFs induced by RP, with high interobserver agreement.

Diffusion tensor imaging beyond brains: Applications in abdominal and pelvic organs

Functional magnetic resonance imaging (MRI) provided critical functional information in addition to the anatomic profiles offered by conventional MRI, and has been enormously used in the initial diagnosis and followed evaluation of various diseases. Diffusion tensor imaging (DTI) is a newly developed and advanced technique that measures the diffusion properties including both diffusion motion and its direction in situ, and has been extensively applied in central nerve system with acknowledged success. Technical advances have enabled DTI in abdominal and pelvic organs. Its application is increasing, yet remains less understood. A systematic overview of clinical application of DTI in abdominal and pelvic organs such as liver, pancreas, kidneys, prostate, uterus, etc., is therefore presented. Exploration of techniques with less artifacts and more normative post-processing enabled generally satisfactory image quality and repeatability of measurement. DTI appears to be more valuable in the evaluation of diffused diseases of organs with highly directionally arranged structures, such as the assessment of function impairment of native and transplanted kidneys. However, the utility of DTI to diagnose focal lesions, such as liver mass, pancreatic and prostate tumor, remains limited. Besides, diffusion of different layers of the uterus and the fiber structure disruption can be depicted by DTI. Finally, a discussion of future directions of research is given. The underlying heterogeneous pathologic conditions of certain diseases need to be further differentiated, and it is suggested that DTI parameters might potentially depict certain pathologic characterization such as cell density. Nevertheless, DTI should be better integrated into the current multi-modality evaluation in clinical practice.

Influence of fractional anisotropy thresholds on diffusion tensor imaging tractography of the periprostatic neurovascular bundle and selected pelvic tissues: do visualized tracts really represent nerves?

Background Diffusion tensor imaging (DTI) tractography has recently been shown to successfully visualize periprostatic tracts allegedly representing the neurovascular bundle. Purpose To examine the impact of different fractional anisotropy (FA) thresholds on the results of DTI tractography in the male pelvis as well as to evaluate the resulting specificity for nerve tracts. Material and Methods Ten healthy male volunteers were examined at 3 Tesla. DTI tractography was performed based on seed points placed circularly around the prostate, in the rectoprostatic angle, the peripheral zone of the prostate, the sciatic nerve, and in addition the urinary bladder using FA thresholds of 0.20, 0.05, and 0.01. DTI tract number and DTI tract length measured with different FA thresholds were compared. ANOVA with repeated measures was used for statistics. Results DTI tract number and tract length were significantly dependent on FA thresholds. While a FA threshold of 0.20 visualized the typical distribution of DTI tracts in the sciatic nerve, a FA threshold of ≤0.05 was necessary to yield results visually mimicking the distribution of nerve tracts in the NVB. However, with such low FA thresholds even in the filled urinary bladder DTI tracts could be visualized. With FA thresholds of 0.20, the number and length of periprostatic DTI tracts did not differ from those measured within the prostate. Conclusion DTI tractography can be used to visualize DTI tracts periprostatically. However, one may doubt that these DTI tracts represent nerve tracts and that the periprostatic neurovascular bundle can be evaluated in a meaningful way with the current methods available.

Computer-aided Detection of Prostate Cancer with MRI: Technology and Applications

One in six men will develop prostate cancer in his lifetime. Early detection and accurate diagnosis of the disease can improve cancer survival and reduce treatment costs. Recently, imaging of prostate cancer has greatly advanced since the introduction of multiparametric magnetic resonance imaging (mp-MRI). Mp-MRI consists of T2-weighted sequences combined with functional sequences including dynamic contrast-enhanced MRI, diffusion-weighted MRI, and magnetic resonance spectroscopy imaging. Because of the big data and variations in imaging sequences, detection can be affected by multiple factors such as observer variability and visibility and complexity of the lesions. To improve quantitative assessment of the disease, various computer-aided detection systems have been designed to help radiologists in their clinical practice. This review paper presents an overview of literatures on computer-aided detection of prostate cancer with mp-MRI, which include the technology and its applications. The aim of the survey is threefold: an introduction for those new to the field, an overview for those working in the field, and a reference for those searching for literature on a specific application.

Zoomed echo-planar diffusion tensor imaging for MR tractography of the prostate gland neurovascular bundle without an endorectal coil: a feasibility study

PURPOSE

The purpose of this study was to assess the feasibility of zoomed echo-planar imaging (EPI) diffusion tensor imaging (DTI) with 2-channel parallel transmission (pTx) for MR tractography of the periprostatic neurovascular bundle (NVB) without an endorectal coil, and to compare its performance to that of conventionally acquired DTI.

METHODS

8 healthy males (28.9 ± 4.6 years) underwent pelvic phased-array coil prostate MRI on a 3T system using both zoomed-EPI DTI (z-DTI) with 2-channel pTx and conventional single-shot spin-echo EPI DTI (c-DTI) acquisitions with 6 encoding directions and b-values of 0 and 1000 s/mm(2). Fractional anisotropy (FA) maps and tractography analysis incorporating 3D visualization of the NVB were performed from each acquisition. Fiber tract counts, estimated signal-to-noise ratio (eSNR), and image quality measures of the FA maps and NVB tractography were compared. Quantitative and image quality measures were compared using Wilcoxon signed rank tests.

RESULTS

3 of 8 subjects had no tracts detected with c-DTI acquisition, while all 8 had tracts detected with z-DTI. z-DTI acquisition yielded significantly more fiber tracts (c-DTI: 77 ± 116 tracts; z-DTI: 430 ± 228 tracts; p = 0.019) and higher eSNR (c-DTI: 2.9 ± 1.2; z-DTI: 13.17 ± 9.9; p = 0.014). Relative to c-DTI acquisitions, z-DTI FA maps showed significantly reduced artifact (p = 0.008) and reduced anatomic distortion of the prostate (p = 0.010), while z-DTI tractography showed significantly better overall visual quality (p = 0.011), tract symmetry (p = 0.010), tract coherence (p = 0.011), and subjective similarity to the actual NVB (p = 0.011).

CONCLUSION

Zoomed-EPI DTI acquisition for tractography of the prostate gland NVB improves quantitative and qualitative measures of image and tract fiber quality, allowing tractography of the NVB at 3T without using an endorectal coil.

Novel methods for mapping the cavernous nerves during radical prostatectomy

The cavernous nerves, which course along the surface of the prostate gland, are responsible for erectile function. During radical prostatectomy, urologists are challenged in preserving these nerves and their function. Cavernous nerves are microscopic and show variable location in different patients; therefore, postoperative sexual potency rates are widely variable following radical prostatectomy. A variety of technologies, including electrical and optical nerve stimulation, dye-based optical fluorescence and microscopy, spectroscopy, ultrasound and magnetic resonance imaging have all been used to study cavernous nerve anatomy and physiology, and some of these methods are also potential intraoperative methods for identifying and preserving cavernous nerves. However, all of these technologies have inherent limitations, including slow or inconsistent nerve responses, poor image resolution, shallow image depth, slow image acquisition times and/or safety concerns. New and emerging technologies, as well as multimodal approaches combining existing methods, hold promise for improved postoperative sexual outcomes and patient quality of life following radical prostatectomy.

Updates in advanced diffusion-weighted magnetic resonance imaging techniques in the evaluation of prostate cancer

Diffusion-weighted magnetic resonance imaging (DW-MRI) is considered part of the standard imaging protocol for the evaluation of patients with prostate cancer. It has been proven valuable as a functional tool for qualitative and quantitative analysis of prostate cancer beyond anatomical MRI sequences such as T2-weighted imaging. This review discusses ongoing controversies in DW-MRI acquisition, including the optimal number of b-values to be used for prostate DWI, and summarizes the current literature on the use of advanced DW-MRI techniques. These include intravoxel incoherent motion imaging, which better accounts for the non-mono-exponential behavior of the apparent diffusion coefficient as a function of b-value and the influence of perfusion at low b-values. Another technique is diffusion kurtosis imaging (DKI). Metrics from DKI reflect excess kurtosis of tissues, representing its deviation from Gaussian diffusion behavior. Preliminary results suggest that DKI findings may have more value than findings from conventional DW-MRI for the assessment of prostate cancer.

Uroflow Stop Test and Potency Recovery: A Surrogate for Pelvic Floor Integrity Post Robotic-Assisted Radical Prostatectomy?

OBJECTIVE

To study the relation between uroflow Stop Test and early recovery of potency following robot-assisted radical prostatectomy (RARP). We recently showed that the ability to completely stop urine flow during voiding, measured objectively by uroflowmetry at the time of catheter removal (uroflow Stop Test) can predict early urinary continence recovery following RARP.

MATERIALS AND METHODS

In this prospective observational cohort, data were collected on 108 patients operated by a single surgeon (AEH). Eighty patients had a positive uroflow Stop Test (group one) and 28 had a negative Stop Test (group two). Patients were followed for a minimum of 2 years. Covariates included age, body mass index, international prostate symptom score and sexual health inventory for men scores, prostate-specific antigen, tumor stage, prostate volume, nerve sparing status, and estimated blood loss.

RESULTS

Preoperative characteristics were comparable between both groups except nerve sparing and prostate-specific antigen which were statistically higher in group one (P <.05). Early 3- and 6-months recovery of erectile function was significantly higher in group one. Potency rates in group one and two at 1, 3, 6, 9, 12, 18, and 24 months were 25% vs 14.3% (P = .241), 54.5% vs 18.5% (P = .001), 55.4% vs 18.5% (P = .001), 56.4% vs 36% (P = .084), 66.6% vs 50% (P = .141), 65.5% vs 56% (P = .404) and 73.2% vs 57.7% (P = .160) respectively. Uroflow Stop Test was independent predictor of early potency recovery on multivariate regression analysis at 6 months [odds ratio 6.042 (confidence interval 95% 1.496-24.413) P = .012].

CONCLUSION

Uroflow Stop Test is simple and can help predict early potency recovery following RARP.

Imaging biomarkers in prostate cancer: role of PET/CT and MRI

Prostate-specific antigen (PSA) is currently the most widely used biomarker of prostate cancer (PCa). PSA suggests the presence of primary tumour and disease relapse after treatment, but it is not able to provide a clear distinction between locoregional and distant disease. Molecular and functional imaging, that are able to provide a detailed and comprehensive overview of PCa extension, are more reliable tools for primary tumour detection and disease extension assessment both in staging and restaging. In the present review we evaluate the role of PET/CT and MRI in the diagnosis, staging and restaging of PCa, and the use of these imaging modalities in prognosis, treatment planning and response assessment. Innovative imaging strategies including new radiotracers and hybrid scanners such as PET/MRI are also discussed.

Multiparametric magnetic resonance imaging vs. standard care in men being evaluated for prostate cancer: a randomized study

OBJECTIVES

To assess whether the proportion of men with clinically significant prostate cancer (PCa) is higher among men randomized to multiparametric magnetic resonance imaging (mp-MRI)/biopsy vs. those randomized to transrectal ultrasound (TRUS)-guided biopsy.

METHODS

In total, 1,140 patients with symptoms highly suggestive of PCa were enrolled and divided in 2 groups of 570 patients to follow 2 different diagnostic algorithms. Group A underwent a TRUS-guided random biopsy. Group B underwent an mp-MRI and a TRUS-guided targeted+random biopsy. The accuracy of mp-MRI in the diagnosis of PCa was calculated using prostatectomy as the standard of reference.

RESULTS

In group A, PCa was detected in 215 patients. The remaining 355 patients underwent an mp-MRI: the findings were positive in 208 and unremarkable in 147 patients. After the second random+targeted biopsy, PCa was detected in 186 of the 208 patients. In group B, 440 patients had positive findings on mp-MRI, and PCa was detected in 417 at first biopsy; 130 group B patients had unremarkable findings on both mp-MRI and biopsy. In the 130 group B patients with unremarkable findings on mp-MRI and biopsy, a PCa Gleason score of 6 or precancerous lesions were detected after saturation biopsy. mp-MRI showed an accuracy of 97% for the diagnosis of PCa.

CONCLUSIONS

The proportion of men with clinically significant PCa is higher among those randomized to mp-MRI/biopsy vs. those randomized to TRUS-guided biopsy; moreover, mp-MRI is a very reliable tool to identify patients to schedule in active surveillance.

Newer concepts in neural anatomy and neurovascular preservation in robotic radical prostatectomy

With more than 60% of radical prostatectomies being performed robotically, robotic-assisted laparoscopic prostatectomy (RALP) has largely replaced the open and laparoscopic approaches and has become the standard of care surgical treatment option for localized prostate cancer in the United States. Accomplishing negative surgical margins while preserving functional outcomes of sexual function and continence play a significant role in determining the success of surgical intervention, particularly since the advent of nerve-sparing (NS) robotic prostatectomy. Recent evidence suggests that NS surgery improves continence in addition to sexual function. In this review, we describe the neuroanatomical concepts and recent developments in the NS technique of RALP with a view to improving the “trifecta” outcomes.

Functional MR imaging of the abdomen

In this article, functional magnetic resonance (MR) imaging techniques in the abdomen are discussed. Diffusion-weighted imaging (DWI) increases the confidence in detecting and characterizing focal hepatic lesions. The potential uses of DWI in kidneys, adrenal glands, bowel, and pancreas are outlined. Studies have shown potential use of quantitative dynamic contrast-enhanced MR imaging parameters, such as K(trans), in predicting outcomes in cancer therapy. MR elastography is considered to be a useful tool in staging liver fibrosis. A major issue with all functional MR imaging techniques is the lack of standardization of the protocol.

Multiparametric MRI for recurrent prostate cancer post radical prostatectomy and postradiation therapy

The clinical suspicion of local recurrence of prostate cancer (PCa) after radical prostatectomy (RP) and after radiation therapy (RT) is based on the onset of biochemical failure. The aim of this paper was to review the current role of multiparametric-MRI (mp-MRI) in the detection of locoregional recurrence. A systematic literature search using the Medline and Cochrane Library databases was performed from January 1995 up to November 2013. Bibliographies of retrieved and review articles were also examined. Only those articles reporting complete data with clinical relevance for the present review were selected. This review article is divided into two major parts: the first one considers the role of mp-MRI in the detection of PCa local recurrence after RP; the second part provides an insight about the impact of mp-MRI in the depiction of locoregional recurrence after RT (interstitial or external beam). Published data indicate an emerging role for mp-MRI in the detection and localization of locally recurrent PCa both after RP and RT which represents an information of paramount importance to perform focal salvage treatments.

Visualization of periprostatic nerve fibers before and after radical prostatectomy using diffusion tensor magnetic resonance imaging with tractography

PURPOSE

The purpose was to evaluate whether the diffusion tensor imaging (DTI) technique can visualize changes in the numbers of periprostatic nerve fibers before and after nerve-sparing and non-nerve-sparing prostatectomy.

METHOD

Fifty-two prostate cancer patients underwent 3-T magnetic resonance imaging including DTI before and after prostatectomy.

RESULTS

After non-nerve-sparing prostatectomy, the numbers of tracts were significantly decreased at base (218.8±198.8 vs. 60.5±88.7), midgland (124.1±134.5 vs. 32.5±45.7), and apex (103.1±127.4 vs. 29.1±57.1). However, after nerve-sparing prostatectomy, the numbers of tracts were not changed significantly at base (170.5±139.7 vs. 127.7±146.0), midgland (134.3±140.8 vs. 83.7±58.3), and apex (64.1±68.4 vs. 62.3±61.9).

CONCLUSION

DTI technique may be feasible for visualization of periprostatic nerve fibers.