Prostate Region Research Articles

PROSTATE DISEASES DIAGNOSIS IN POWER DOPPLER SONOGRAPHY

In order to detect early prostate cancer, physicians usually apply the ultrasound imaging to visualize prostate for diagnosis. However, the traditional gray-scale ultrasound images that obtained from transrectal ultrasound of the prostate are often limited in diagnosing prostate cancer because of cancer heterogeneity, which makes direct diagnosing on the image difficult. Power Doppler ultrasound images improve the diagnosis by providing extra information of blood flow. Previous study has shown that increased blood inflow exists in prostate cancer. It is not difficult to differentiate the malignancy from benign prostate diseases by inspecting Doppler spectrum at bilateral neurovascular bundle sites and using resistive index. Although it is effective; however, it is hand-held, time-consuming, and only limited in a small and static region, which might not represent the real status of the whole prostate. Therefore, this study proposed an integrated dynamic approach to estimate the resistive index of blood flow in regions of interest within or all over the whole prostate. Merits of the proposed approach include the follows: resistive index can be calculated in serial prostate frames; the calculation can be performed on integral prostate region; and the proposed approach shortened the time needed to complete the calculation on whole prostate. Experimental results show that dynamic resistive index is better than conventional resistive index, and comparable with Prostate specific antigen (PSA) test in diagnosing prostate cancer, indicating high performance of the proposed approach, which also reveals feasibility and effectively of it.

Feasibility and Preliminary Experience of Quantitative T2* Mapping at 3.0 T for Detection and Assessment of Aggressiveness of Prostate Cancer

To assess the feasibility of quantitative T2* mapping at 3.0T for prostate cancer detection and to investigate the use of T2* values to characterize tumor aggressiveness, with whole-mount step-section pathologic analysis as the reference standard. Prostate multiecho T2* was performed in 55 consecutive patients with prostate cancer using a multishot fast-field echo sequence at 3.0T magnetic resonance imaging. T2* mapping was obtained by exponentially fitting the multiecho T2* images pixel by pixel with different echo times for each slice. Generalized estimating equations were used to test the T2* value difference between normal and malignant prostate regions and the association between T2* value and tumor Gleason scores. The T2* values of the cancerous prostatic regions (mean: 42.51±0.65milliseconds) were significantly lower (P<.001) than those of the normal prostatic regions (mean: 74.87±0.99milliseconds). Adopting a threshold value of 59.27milliseconds, T2* mapping resulted in 94.8% sensitivity and 77.3% specificity in the identification of prostate cancer. A lower mean T2* value was significantly associated with a higher tumor Gleason score (mean T2* values of 53.53, 43.75, 33.66, and 22.95 milliseconds were associated with Gleason score of 3+3, 3+4, 4+3, and ≥8, respectively P<.05). From these preliminary data, quantitative T2* mapping seems to be a potential method in the characterization of prostate cancer. T2* mapping may provide additional quantitative information that significantly correlated with prostate cancer aggressiveness.

Sonoelastographic evaluation with the determination of compressibility ratio for symmetrical prostatic regions in the diagnosis of clinically significant prostate cancer.

AimSonoelastography is a technique that assesses tissue hardness/compressibility. Utility and sensitivity of the method in prostate cancer diagnostics were assessed compared to the current gold standard in prostate cancer diagnostics i.e. systematic biopsy.Material and methodsThe study involved 84 patients suspected of prostate cancer based on elevated PSA levels or abnormal per rectal examination findings. Sonoelastography was used to evaluate the prostate gland. In the case of regions with hardness two-fold greater than that of symmetric prostate area (strain ratio >2), targeted biopsy was used; which was followed by an ultrasound-guided 8- or 10-core systematic biopsy (regardless of sonoelastography-indicated sites) as a reference point.ResultsThe mean age of patients was 69 years. PSA serum levels ranged between 1.02 and 885 ng/dl. The mean prostate volume was 62 ml (19–149 ml). Prostate cancer was found in 39 out of 84 individuals. Statistically significant differences in strain ratios between cancers and benign lesions were shown. Sonoelastography guided biopsy revealed 30 lesions – overall sensitivity 77% (sensitivity of the method – 81%). Sonoelastographic sensitivity increased depending on cancer stage according to the Gleason grading system: 6–60%, 7–75%, 8–83%, 9/10–100%. The estimated sensitivity of systematic biopsy was 92%.ConclusionsSonoelastography shows higher diagnostic sensitivity in prostate cancer diagnostics compared to conventional imaging techniques, i.e. grey-scale TRUS, Doppler ultrasound. It allows to reduce the number of collected tissue cores, and thus limit the incidence of complications as well as the costs involved. Sonoelastography using the determination of compressibility ratio for symmetrical prostatic regions may prove useful in the detection of clinically significant prostate cancer.

TU‐F‐BRF‐02: MR‐US Prostate Registration Using Patient‐Specific Tissue Elasticity Property Prior for MR‐Targeted, TRUS‐Guided HDR Brachytherapy

Purpose:High‐dose‐rate (HDR) brachytherapy has become a popular treatment modality for prostate cancer. Conventional transrectal ultrasound (TRUS)‐guided prostate HDR brachytherapy could benefit significantly from MR‐targeted, TRUS‐guided procedure where the tumor locations, acquired from the multiparametric MRI, are incorporated into the treatment planning. In order to enable this integration, we have developed a MR‐TRUS registration with a patient‐specific biomechanical elasticity prior.Methods:The proposed method used a biomechanical elasticity prior to guide the prostate volumetric B‐spline deformation in the MRI and TRUS registration. The patient‐specific biomechanical elasticity prior was generated using ultrasound elastography, where two 3D TRUS prostate images were acquired under different probe‐induced pressures during the HDR procedure, which takes 2‐4 minutes. These two 3D TRUS images were used to calculate the local displacement (elasticity map) of two prostate volumes. The B‐spline transformation was calculated by minimizing the Euclidean distance between the normalized attribute vectors of the prostate surface landmarks on the MR and TRUS. This technique was evaluated through two studies: a prostate‐phantom study and a pilot study with 5 patients undergoing prostate HDR treatment. The accuracy of our approach was assessed through the locations of several landmarks in the post‐registration and TRUS images; our registration results were compared with the surface‐based method.Results:For the phantom study, the mean landmark displacement of the proposed method was 1.29±0.11 mm. For the 5 patients, the mean landmark displacement of the surface‐based method was 3.25±0.51 mm; our method, 1.71±0.25 mm. Therefore, our proposed method of prostate registration outperformed the surfaced‐based registration significantly.Conclusion:We have developed a novel MR‐TRUS prostate registration approach based on patient‐specific biomechanical elasticity prior. Successful integration of multi‐parametric MR and TRUS prostate images provides a prostate‐cancer map for treatment planning, enables accurate dose planning and delivery, and potentially enhances prostate HDR treatment outcome.

TH‐A‐BRF‐08: Deformable Registration of MRI and CT Images for MRI‐Guided Radiation Therapy

Purpose:To evaluate the quality of a commercially available MRI‐CT image registration algorithm and then develop a method to improve the performance of this algorithm for MRI‐guided prostate radiotherapy.Methods:Prostate contours were delineated on ten pairs of MRI and CT images using Eclipse. Each pair of MRI and CT images was registered with an intensity‐based B‐spline algorithm implemented in Velocity. A rectangular prism that contains the prostate volume was partitioned into a tetrahedral mesh which was aligned to the CT image. A finite element method (FEM) was developed on the mesh with the boundary constraints assigned from the Velocity generated displacement vector field (DVF). The resultant FEM displacements were used to adjust the Velocity DVF within the prism. Point correspondences between the CT and MR images identified within the prism could be used as additional boundary constraints to enforce the model deformation. The FEM deformation field is smooth in the interior of the prism, and equal to the Velocity displacements at the boundary of the prism. To evaluate the Velocity and FEM registration results, three criteria were used: prostate volume conservation and center consistence under contour mapping, and unbalanced energy of their deformation maps.Results:With the DVFs generated by the Velocity and FEM simulations, the prostate contours were warped from MRI to CT images. With the Velocity DVFs, the prostate volumes changed 10.2% on average, in contrast to 1.8% induced by the FEM DVFs. The average of the center deviations was 0.36 and 0.27 cm, and the unbalance energy was 2.65 and 0.38 mJ/cc3 for the Velocity and FEM registrations, respectively.Conclusion:The adaptive FEM method developed can be used to reduce the error of the MIbased registration algorithm implemented in Velocity in the prostate region, and consequently may help improve the quality of MRI‐guided radiation therapy.

Computational system to create an entry file for replicating I-125 seeds simulating brachytherapy case studies using the MCNPX code

Purpose:A computational system was developed for this paper in the C++ programming language, to create a 125 I radioactive seed entry file, based on the positioning of a virtual grid (template) in voxel geometries, with the purpose of performing prostat e cancer treatment simulations using the MCNPX code. Method:The system is fed with information from the plannin g system with regard to each seeds location and its depth, and an entry file is automatically created with all the cards (instruction s) for each seed regarding their cell blocks and surfaces spread out spatially in the 3D environment. The system provides with precision a reproduction of the clinical scenario for the MCNPX codes simulation environment, thereby allowing the techniques in -depth study.Results and Conclusion: The preliminary results from this study showed that the lateral pe -numbra of uniform scanning proton beams was less sensitive In order to validate the computational system, an entry file was created with 88 125I seeds that were inserted in the phantoms MAX06 prostate region with initial activity determined for the seeds at the 0.27 mCi value. Is dose curves were obtained in all the prostate slices in 5 mm steps in the 7 to 10 cm interval, totaling 7 slices. Variance reduction

A comparison of rigid registration methods for prostate localization on CBCT and the dependence on rectum distension

We evaluated automatic three-dimensional intensity-based rigid registration (RR) methods for prostate localization on CBCT scans and studied the impact of rectum distension on registration quality. 106 CBCT scans of 9 prostate patients were used. Each one was registered to the planning computed tomography (CT) scan using different methods: (a) global registration, (b) pelvis bony structure registration, (c) bony registration refined by a local prostate registration using the CT clinical target volume (CTV) expanded with 1, 3, 5, 8, 10, 12, 15 or 20-mm margin. Automatic CBCT contours were generated after propagation of the manual CT contours. To evaluate results, a radiation oncologist was asked to manually delineate the CTV on the CBCT scans (gold standard). The Dice similarity coefficients between propagated and manual CBCT contours were calculated.

Preliminary Results of a Pilot Study of Focal Salvage High-Dose-Rate Prostate Brachytherapy in Patients with Local Recurrence after Definitive External Beam Radiotherapy

Purpose: Permanent prostate implants (PPI) are performed since 1994 in our institution. The analysis of 1794 patients treated between 1994 and 2012 was done to evaluate the seed loss and migration rate over this period. The impact of implantation techniques on seed migration, such as the introduction of intraoperative technology, was evaluated. The correlation between seed loss/migration and the experience of the physician performing the implant was also explored. Materials and Methods: Post-implant evaluations were done 30 days after the implant for all patients. Migration was defined as one or more seed found outside the prostate region and confirmed by imaging (CT or kV). Most of the time, the migrated seeds were located in the lungs while uncommon locations included kidneys, heart and sacrum. Seed loss was defined as at least one seed missing at the post-implant evaluation, excluding the migrated seeds found in the patient. Seeds might be lost through micturition but miscount on kV images remains a possibility. Since January 2004, all PPI patients were surveyed using a collimated NaI gamma scintillator to detect seed migration to the chest. Before this date, the total number of migrated and lost seeds is reported without differentiation. The seed loss and migration rate are reported for three different implantation techniques: manual, guidance and robotic. The manual group (G1) consists of implants performed with a pre-planning technique and 2D TRUS insertion. The guidance group (G2) were done using OR planning and 3D TRUS insertion with guidance (SPOTPRO, Nucletron). The robotic group (G3) were implanted with the FIRST system (Nucletron) similar to the second group G2 but with robotic needle extraction. Groups were compared using Pearson khi-2 test. Results: The proportions of patients with seed migration were 17%, 15.5% and 8% for the G1, G2 and G3 groups respectively. The difference between G1-G3 or G2-G3 are statistically significant (p5 0.0028 and 0.002). For patients with either migration or loss, rates were 39%, 26% and 23.6% for the G1, G2 and G3 groups, respectively. There is a significant difference between G1-G3 (p 5 0.0005). The introduction of intra-op planning between 2003 and 2004 had a significant impact on both migration and seed loss rates (p50.0049). The rate of seed migration/loss tended to decrease as physicians gained experience in the implantation technique. Conclusions: Seed migration and loss rates are related to the implantation technique, with the robotic-assisted technique leading to the best results. Data also suggest that the experience of the physician performing the implant has an impact on migration/loss rates. PD56

New acquisition protocol of 18F-choline PET/CT in prostate cancer patients: review of the literature about methodology and proposal of standardization.

Purpose. (1) To evaluate a new acquisition protocol of 18F-choline (FCH) PET/CT for prostate cancer patients (PC), (2) to review acquisition 18F-choline PET/CT methodology, and (3) to propose a standardized acquisition protocol on FCH PET/CT in PC patients. Materials. 100 consecutive PC patients (mean age 70.5 years, mean PSA 21.35 ng/mL) were prospectively evaluated. New protocol consisted of an early scan of the pelvis immediately after the injection of the tracer (1 bed position of 4 min) followed by a whole body scan at one 1 hour. Early and 1 hour images were compared for interfering activity and pathologic findings. Results. The overall detection rate of FCH PET/CT was 64%. The early static images of the pelvis showed absence of radioactive urine in ureters, bladder, or urethra which allowed a clean evaluation of the prostatic fossae. Uptake in the prostatic region was better visualized in the early phase in 26% (7/30) of cases. Other pelvic pathologic findings (bone and lymph nodes) were visualized in both early and late images. Conclusion. Early 18F-choline images improve visualization of abnormal uptake in prostate fossae. All pathologic pelvic deposits (prostate, lymph nodes, and bone) were visualized in both early and late images.

Seasonal changes in the prostatic complex of Artibeus planirostris (Chiroptera: Phyllostomidae)

The male reproductive accessory glands are important organs that secrete products that ensure the survival, viability and motility of spermatozoa, not only in the male reproductive tract, but also in the female. Most studies relating to the reproduction of bats do not include these glands, and detailed studies of these glands describing annual variations in the morphology and physiology are scarce. The aim of this study was to evaluate the impact of these variations on morphophysiology of the prostatic complex (PC) of Artibeus planirostris (Chiroptera: Phyllostomidae). Adult males were collected from June 2009 to July 2010, and the PC was subjected to various analyses. We observed that the PC showed marked variations throughout the year. Both PC and testicular weight increased synchronously with an increasing rate of circulating testosterone, from the autumn until summer, demonstrating that both organs are regulated by this hormone. Each region of the PC (ventral and dorsal) was unique and distinct. The ventral region showed the glandular lumen as a predominant component, in contrast to the dorsal introduced epithelium; acid phosphatase activity was observed in the epithelium of all acini in the dorsal region, but only in the stroma of the ventral region, in addition each region responded differently to variations in the environment and circulating testosterone. We concluded that the PC of A. planirostris produces two secretory peaks, which were related to a gradual increase in the rate of circulating testosterone, which stimulates both of the prostate regions to prepare for the two reproductive periods.

Structure, histochemistry and seasonal variations of the male reproductive accessory glands in the Pallas's mastiff bat, Molossus molossus (Chiroptera: Molossidae).

Due to their wide geographical distribution, bats suffer considerable influence from abiotic factors on their reproductive strategies, detected through behavioural or functional assessment of the gonads and accessory glands. The present study aimed to characterise anatomically and morphologically the reproductive accessory glands (RAGs) of Molossus molossus (Molossidae) and evaluate their seasonal variations. The RAGs were removed, fixed, sectioned after histological processing and submitted to the following stains: haematoxylin-eosin, periodic acid--Schiff (PAS) and Gömöri's reticulin. Our data demonstrated that the RAGs of M. molossus are composed of a semi-lobed prostatic complex associated with the urethra and a pair of inguinal bulbourethral glands. Histology and three-dimensional reconstruction of the prostatic complex demonstrated the existence of two regions: ventral and dorsal (named according to the position around the urethra). The two regions had distinctive morphological and histological differences, with the ventral region being the most prominent and the dorsal formed by four lobes. Considering the seasonal evaluation, we can infer that the prostatic complex of M. molossus is active throughout the seasons in São Paulo State (Brazil) and, although each of the prostatic regions has inherent characteristics, they synchronise to establish the main reproductive peak in spring (early rainy season).

Abstract B129: Clinical implications of inter- and intra- prostatic heterogeneity.

Abstract Men with localized prostate cancer vary widely in clinical outcome, with a 30-50% failure rate after primary treatment. There is thus significant interest in developing genomically refined prognostic groups. We sought to evaluate the extent of genetic heterogeneity, both between patients (inter-prostate) and within individual prostate glands (intra-prostate) to assess the impact of genetic heterogeneity on risk stratification within a tight clinical cohort. Copy number aberrations (CNAs) from 75 Gleason 7 patients were determined by OncoScan SNP microarrays. We measure the percentage of genome involved in a CNA, termed percent genome aberration (PGA), a proxy for genomic instability. Additionally, whole genome sequencing was applied to 10 intermediate-risk prostate tumours and matched blood, including multiple manually macro-dissected regions from 5 of the prostates (range 2 to 9). Somatic single nucleotide variants (SNVs) and genomic rearrangements (GR) were extracted from each patient. We find a high degree of inter-prostatic heterogeneity between the 75 Gleason 7 patients, with the number of CNAs per patient ranging from 0 to 929, corresponding to PGA 0 to 16.7%. Known prognostic markers can differentiate between patients at higher risk for biochemical recurrence, but only account for a fraction of the cohort. Notably, when these prognostic genes are examined within multiple regions of five independent tumours, they differ in copy number between cancerous regions of the same prostate. For example, TP53 is deleted in 1/2, 1/3, 4/9, 0/4, and 4/5 prostate regions. Indeed, phylogenetic analysis of geographically distinct regions revealed multi-clonal disease in two of the five patients; separate analyses based on SNVs, CNAs, and GRs all concluded that these patient have two genetically distinct cancers within their prostate. We demonstrate dramatic levels of inter- and intra- prostate genetic heterogeneity within pathologically identical or similar cancers. The observed intra-prostatic genomic heterogeneity, both in terms of multi-focal and multi-clonal disease, has critical implications for clinical management. Prognostic information obtained by biopsy may be inconsistent depending on the site of biopsy, and applying personalized medicine to prostate cancer will be challenging. This study highlights the need for further evaluation of how intra-prostatic heterogeneity is related to patient prognosis. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B129. Citation Format: Emilie Lalonde, Paul C. Boutros, Michael Fraser, Richard de Borja, Nicholas J. Harding, Dominique Trudel, Alice Meng, Pablo H. Hennings-Yeomans, Andrew McPherson, Amin Zia, Jianxin Wang, Timothy Beck, Natalie S. Fox, Taryne Chong, Michelle Sam, Jeremy Johns, Lee Timms, Nicholas Buchner, Sohrab Shah, Cenk Sahinalp, Thomas J. Hudson, John D. McPherson, Theodorus van der Kwast, Robert G. Bristow. Clinical implications of inter- and intra- prostatic heterogeneity. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B129.

Transition Zone Prostate Cancer: Incremental Value of Diffusion-weighted Endorectal MR Imaging in Tumor Detection and Assessment of Aggressiveness

To evaluate the incremental value of using diffusion-weighted magnetic resonance (MR) imaging in addition to T2-weighted imaging for the detection of prostate cancer in the transition zone and the assessment of tumor aggressiveness. This retrospective HIPAA-compliant institutional review board-approved study included 156 consecutive patients (median age, 59.2 years) who underwent MR imaging before radical prostatectomy. Two readers who were blinded to patient data independently recorded their levels of suspicion on a five-point scale of the presence of transition zone tumors on the basis of T2-weighted imaging alone and then, 4 weeks later, diffusion-weighted imaging and T2-weighted imaging together. Apparent diffusion coefficients (ADCs) were measured in transition zone cancers and glandular and stromal benign prostatic hyperplasia. Areas under the receiver operating characteristic curves were used to evaluate detection accuracy, and generalized linear models were used to test ADC differences between benign and malignant prostate regions. Whole-mount step-section histopathologic examination was the reference standard. In overall tumor detection, addition of diffusion-weighted imaging to T2-weighted imaging improved the areas under the receiver operating characteristic curves for readers 1 and 2 from 0.60 and 0.60 to 0.75 and 0.71, respectively, at the patient level (P = .004 for reader 1 and P = .027 for reader 2) and from 0.64 and 0.63 to 0.73 and 0.68, respectively, at the sextant level (P = .001 for reader 1 and P = .100 for reader 2). Least squares mean ADCs (× 10(-3) mm(2)/sec) in glandular and stromal benign prostatic hyperplasia were 1.44 and 1.09, respectively. Mean ADCs were inversely associated with tumor Gleason scores (1.10, 0.98, 0.87, and 0.75 for Gleason scores of 3 + 3, 3 + 4, 4 + 3, and ≥ 4 + 4, respectively). Use of diffusion-weighted imaging in addition to T2-weighted imaging improved detection of prostate cancer in the transition zone, and tumor ADCs were inversely associated with tumor Gleason scores in the transition zone.

Is Fosfomycin a Potential Treatment Alternative for Multidrug-Resistant Gram-Negative Prostatitis?

Multidrug-resistant gram-negative bacterial (MDR-GNB) infections of the prostate are an increasing problem worldwide, particularly complicating transrectal ultrasound (TRUS)-guided prostate biopsy. Fluoroquinolone-based regimens, once the mainstay of many protocols, are increasingly ineffective. Fosfomycin has reasonable in vitro and urinary activity (minimum inhibitory concentration breakpoint ≤64 µg/mL) against MDR-GNB, but its prostatic penetration has been uncertain, so it has not been widely recommended for the prophylaxis or treatment of MDR-GNB prostatitis. In a prospective study of healthy men undergoing a transurethral resection of the prostate for benign prostatic hyperplasia, we assessed serum, urine, and prostatic tissue (transition zone [TZ] and peripheral zone [PZ]) fosfomycin concentrations using liquid chromatography-tandem mass spectrometry, following a single 3-g oral fosfomycin dose within 17 hours of surgery. Among the 26 participants, mean plasma and urinary fosfomycin levels were 11.4 ± 7.6 µg/mL and 571 ± 418 µg/mL, 565 ± 149 minutes and 581 ± 150 minutes postdose, respectively. Mean overall prostate fosfomycin levels were 6.5 ± 4.9 µg/g (range, 0.7-22.1 µg/g), with therapeutic concentrations detectable up to 17 hours following the dose. The mean prostate to plasma ratio was 0.67 ± 0.57. Mean concentrations within the TZ vs PZ prostate regions varied significantly (TZ, 8.3 ± 6.6 vs PZ, 4.4 ± 4.1 µg/g; P = .001). Only 1 patient had a mean prostatic fosfomycin concentration of <1 µg/g, whereas the majority (70%) had concentrations ≥4 µg/g. Fosfomycin appears to achieve reasonable intraprostatic concentrations in uninflamed prostate following a single 3-g oral dose, such that it may be a potential option for prophylaxis pre-TRUS prostate biopsy and possibly for the treatment of MDR-GNB prostatitis. Formal clinical studies are now required.

Multispectral Photoacoustic Imaging of Prostate Cancer: Preliminary Ex-vivo Results

Objective:The objective of this study is to validate if ex-vivo multispectral photoacoustic (PA) imaging can differentiate between malignant prostate tissue, benign prostatic hyperplasia (BPH), and normal human prostate tissue.Materials and Methods:Institutional Review Board's approval was obtained for this study. A total of 30 patients undergoing prostatectomy for biopsy-confirmed prostate cancer were included in this study with informed consent. Multispectral PA imaging was performed on surgically excised prostate tissue and chromophore images that represent optical absorption of deoxyhemoglobin (dHb), oxyhemoglobin (HbO2), lipid, and water were reconstructed. After the imaging procedure is completed, malignant prostate, BPH and normal prostate regions were marked by the genitourinary pathologist on histopathology slides and digital images of marked histopathology slides were obtained. The histopathology images were co-registered with chromophore images. Region of interest (ROI) corresponding to malignant prostate, BPH and normal prostate were defined on the chromophore images. Pixel values within each ROI were then averaged to determine mean intensities of dHb, HbO2, lipid, and water.Results:Our preliminary results show that there is statistically significant difference in mean intensity of dHb (P < 0.0001) and lipid (P = 0.0251) between malignant prostate and normal prostate tissue. There was difference in mean intensity of dHb (P < 0.0001) between malignant prostate and BPH. Sensitivity, specificity, positive predictive value, and negative predictive value of our imaging system were found to be 81.3%, 96.2%, 92.9% and 89.3% respectively.Conclusion:Our preliminary results of ex-vivo human prostate study suggest that multispectral PA imaging can differentiate between malignant prostate, BPH and normal prostate tissue.

Role of Endorectal Prostate MRI in Patients with Initial Suspicion of Prostate Cancer

To evaluate the role of conventional endorectal prostate MRI in patients with initial suspicion of prostate cancer. Ethics board approval was received for this retrospective study of 87 men who underwent 1.5-Tesla conventional prostate MRI with a combination of endorectal and body phased-array coils for suspected prostate cancer before their first systematic 12-core TRUS-guided biopsy. Three radiologists independently analyzed the images, dividing the prostate into 12 regions corresponding to the biopsy scheme and scoring each region for the presence of prostate cancer on a 5-point scale. Results were analyzed by prostate region. ROC analysis was done and descriptive statistics were calculated. The negative predictive value, specificity, sensitivity and positive predictive value were calculated using dichotomized scores (benign tissue = scores of 1 and 2; malignant tissues = scores of 3, 4, and 5). Biopsy revealed cancer in 47/87 patients (26 low-grade [Gleason score 6]; 21 high-grade [Gleason score ≥ 3 + 4]), and 184/1044 cores (77 low-grade and 107 high-grade) with a median of 3 positive cores per cancer patient (range 1 - 12). The areas under ROC curves were 0.65 - 0.67 for cancer detection by region overall and 0.75 - 0.76 for the detection of high-grade cancer by region. Statistic figures for the detection of all cancers/high-grade cancers by region were as follows: negative predictive value, 87.4 - 88.2 %/92.6 - 93.1 %; specificity, 72.3 - 79.4 %/71.5 - 79.8 %; sensitivity, 49.5 - 54.8 %/62.6 - 69.2 %; and positive predictive value, 29.3 - 34.0 %/29.4 - 34.7 %. In patients with suspected prostate cancer, negative MRI findings indicate the absence of high-grade prostate cancer on subsequent TRUS-guided 12-core biopsy with high probability. However, agreement between conventional 1.5-T endorectal prostate MRI and systematic 12-core TRUS-guided biopsy for the detection of prostate cancer appears to be moderate.

Histology core‐specific evaluation of the European Society of Urogenital Radiology (ESUR) standardised scoring system of multiparametric magnetic resonance imaging (mpMRI) of the prostate

To evaluate the Prostate Imaging Reporting and Data System (PIRADS) in multiparametric magnetic resonance imaging (mpMRI) based on single cores and single-core histology. To calculate positive (PPV) and negative predictive values (NPV) of different modalities of mpMRI. We performed MRI-targeted transrectal ultrasound-guided perineal prostate biopsies on 50 patients (mean age 66 years, mean PSA level of 9.9 ng/mL) with suspicion of prostate cancer. The biopsy trajectories of every core taken were documented in three dimensions (3D) in a 3D-prostate model. Every core was evaluated separately for prostate cancer and the performed biopsy trajectories were projected on mpMRI images. PIRADS scores of 1177 cores were then assessed by a histology 'blinded' uro-radiologist in T2-weighted (T2W), dynamic contrast-enhanced (DCE), diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy (MRS). The PIRADS score was significantly higher in cores positive for cancer than in negative cores. There was a significant correlation between the PIRADS score and histopathology for every modality. Receiver operating characteristic (ROC) analysis showed excellent specificity for T2W (90% peripheral zone/97% transition zone) and DWI (98%/97%) images regardless of the prostate region observed. These numbers decreased for DCE (80%/93%) and MRS (76%/83%). All modalities had NPVs of 99%, if a PIRADS score threshold of 2 (for T2W, DCE, and MRS) or 3 (for DWI) was used. However, PPVs were low. Our results show that PIRADS scoring is feasible for clinical routine and allows standardised reporting. PIRADS can be used as a decision-support system for targeting of suspicious lesions. mpMRI has a high NPV for prostate cancer and, thus, might be a valuable tool in the initial diagnostic evaluation.

Histopathologic Evaluation of Neurovascular Bundles and Periprostatic Tissue in Interfascial and Intrafascial Nerve-sparing Radical Prostatectomy Technique: A Cadaveric Anatomic Study

To compare interfascial (IEF) or intrafascial (IAF) periprostatic nerve dissection technique in prostate tissue using immunohistochemical methods in fresh cadavers. Prostate tissues of 25 fresh cadavers were removed from rectum and other surrounding structures. IEF nerve dissection (n= 25) was performed on the right and IAF nerve (n= 25) dissection on the left side of each prostate under direct visualization. The base, center, and apex of each prostate lobes andfascia dissected were sampled for blind histopathologic evaluation. Total counts of nerve, artery, and vein were performed on hematoxylin and eosin stained sections, whereas sympathetic and parasympathetic nerve counts were performed on immunohistochemical stained sections. Iatrogenic surgical margin injury at base, center, and apex detected were compared between groups. Thickness of neurovascular bundle dissected in IAF was found significantly higher than IEF technique. The number of residual sympathetic fibers after dissection of neurovascular bundle was found significantly higher in IAF group. There were significant decreases in total nerve, parasympathetic, and sympathetic nerve counts only at the central region of prostate in IAF group. Asignificant decrease was found in the number of residual vein left in the fascia only at the apex by IAF dissection. Of surgical margin injury results, no significant difference was detected between IAF and IEF groups at any location. IAF provides better preservation of sympathetic but not parasympathetic fibers without increasing surgical injury of prostate capsule.

Transition Zone Prostate Cancer: Incremental Value of Diffusion-weighted Endorectal MR Imaging in Tumor Detection and Assessment of Aggressiveness

To evaluate the incremental value of using diffusion-weighted magnetic resonance (MR) imaging in addition to T2-weighted imaging for the detection of prostate cancer in the transition zone and the assessment of tumor aggressiveness. This retrospective HIPAA-compliant institutional review board-approved study included 156 consecutive patients (median age, 59.2 years) who underwent MR imaging before radical prostatectomy. Two readers who were blinded to patient data independently recorded their levels of suspicion on a five-point scale of the presence of transition zone tumors on the basis of T2-weighted imaging alone and then, 4 weeks later, diffusion-weighted imaging and T2-weighted imaging together. Apparent diffusion coefficients (ADCs) were measured in transition zone cancers and glandular and stromal benign prostatic hyperplasia. Areas under the receiver operating characteristic curves were used to evaluate detection accuracy, and generalized linear models were used to test ADC differences between benign and malignant prostate regions. Whole-mount step-section histopathologic examination was the reference standard. In overall tumor detection, addition of diffusion-weighted imaging to T2-weighted imaging improved the areas under the receiver operating characteristic curves for readers 1 and 2 from 0.60 and 0.60 to 0.75 and 0.71, respectively, at the patient level (P = .004 for reader 1 and P = .027 for reader 2) and from 0.64 and 0.63 to 0.73 and 0.68, respectively, at the sextant level (P = .001 for reader 1 and P = .100 for reader 2). Least squares mean ADCs (× 10(-3) mm(2)/sec) in glandular and stromal benign prostatic hyperplasia were 1.44 and 1.09, respectively. Mean ADCs were inversely associated with tumor Gleason scores (1.10, 0.98, 0.87, and 0.75 for Gleason scores of 3 + 3, 3 + 4, 4 + 3, and ≥ 4 + 4, respectively). Use of diffusion-weighted imaging in addition to T2-weighted imaging improved detection of prostate cancer in the transition zone, and tumor ADCs were inversely associated with tumor Gleason scores in the transition zone.

Kinetic Modeling Application to (18)F-fluoroethylcholine Positron Emission Tomography in Patients with Primary and Recurrent Prostate Cancer Using Two-tissue Compartmental Model.

Although 18F-fludeoxyglucose-positron emission tomography (PET) is the most applied diagnostic method in tumor staging, its role in prostate cancer (PCA) is limited because glucose metabolism tends to be low unless PCA has high Gleason score. Alternatively, choline PET was introduced as a valuable imaging method. Kinetic analysis of PET acquisition has increasingly gained momentum as an investigative tool because it provides a non-invasive approach to obtain kinetic and metabolic data from tissues of interest including transport and metabolism of the administered material. In this regard, we sought to apply it in 18F-fluoroethylcholine (FECH)-PET/computed tomography (CT) in patients with PCA. 64 patients, the mean age 69 (range: 47-87 years) with primary/recurrent PCA were encompassed. They underwent 18F-FECH-PET started with a dynamic acquisition using a 20-frame each 30 s over the prostate region and followed at 1 h post-injection by a static whole body imaging. The kinetic evaluation of the data was performed using the software package PMOD (PMOD Technologies Ltd., Zürich, Switzerland). Significant increase in mean values for K1, K3, FD, standardized uptake value (SUV) and global influx in tumor tissue versus normal tissue (P < 0.05). Moderate but significant correlation (r: 0.28, P = 0.023) between SUV and K1. By contrast, no correlation between SUV and K3 (r: −0.08, P = 0.79). In patients with recurrent tumors, there is no significant difference in all kinetic parameters and SUV (P > 0.1) between the different types of recurrences. The kinetic analysis of dynamic FECH-PET provides a novel method in primary PCA diagnosis and could be of potential value in the delineation of tumor focus.