Electron Donors Rather Than Reactive Oxygen Species Needed for Therapeutic Photochemical Reaction of Near-Infrared Photoimmunotherapy.

Near-infrared photoimmunotherapy (NIR-PIT) employs molecularly targeted antibodies conjugated with a photoabsorbing silicon-phthalocyanine dye derivative which binds to cancer cells. Application of NIR light following binding of the antibody-photoabsorber conjugates (APCs) results in ligand release on the dye, dramatic changes in solubility of the APC-antigen complex, and rapid, irreversible cell membrane damage of cancer cells in a highly selective manner, resulting in a highly immunogenic cell death. Clinically, this process results in edema after treatment mediated by reactive oxygen species (ROS). Based on the chemical and biological mechanism of NIR-PIT cytotoxicity and edema formation, in order to minimize acute inflammatory edema without compromising therapeutic effects, l-sodium ascorbate (l-NaAA) was administered to quench harmful ROS and accelerate the ligand release reaction. l-NaAA suppressed acute edema by reducing ROS after NIR-PIT yet did not alter the therapeutic effects. NIR-PIT could be performed safely under existence of l-NaAA without side effects caused by unnecessary ROS production.

Near Infrared Photoimmunotherapy in a Transgenic Mouse Model of Spontaneous Epidermal Growth Factor Receptor (EGFR)-expressing Lung Cancer.

Near infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment that combines the specificity of antibodies for targeting tumors with the toxicity induced by a sensitive photoabsorber following exposure to NIR light. Most studies of NIR-PIT have been performed in xenograft models of cancer. The purpose of this study was to evaluate the therapeutic effects of NIR-PIT in a transgenic model of spontaneous lung cancer expressing human EGFR (hEGFR-TL). Mice were separated into 3 groups for the following treatments: (1) no treatment (control); (2) 150 µg of photoabsorber, IR700, conjugated to panitumumab, an antibody targeting EGFR [antibody-photoabsorber conjugate (APC)] intravenously (i.v.) only; (3) 150 µg of APC i.v. with NIR light administration. Each treatment was performed every week up to three weeks. MRI was performed 1 day before and 3, 6, 13, 20, 27, and 34 days after first NIR-PIT. The relative volume of lung tumors was calculated from the tumor volume at each MRI time point divided by the initial volume. Steel test for multiple comparisons was used to compare the tumor volume ratio with that of control. Tumor volume ratio was inhibited significantly in the NIR-PIT group compared with control group (P < 0.01 at all time points). In conclusion, NIR-PIT effectively treated a spontaneous lung cancer in a hEGFR-TL transgenic mouse model. MRI successfully monitored the therapeutic effects of NIR-PIT. Mol Cancer Ther; 16(2); 408-14. ©2016 AACR.

Optimal high b-value for diffusion weighted MRI in diagnosing high risk prostate cancers in the peripheral zone.

PURPOSE: To retrospectively determine the optimal b-value(s) of diffusion-weighted imaging (DWI) associated with intermediate-high risk cancer in the peripheral zone (PZ) of the prostate. MATERIALS AND METHODS: Forty-two consecutive patients underwent multi b-value (16 evenly spaced b-values between 0 and 2000 s/mm2 ) DWI along with multi-parametric MRI (MP-MRI) of the prostate at 3 Tesla followed by trans-rectal ultrasound/MRI fusion guided targeted biopsy of suspicious lesions detected at MP-MRI. Computed DWI images up to a simulated b-value of 4000 s/mm2 were also obtained using a pair of b-values (b = 133 and 400 or 667 or 933 s/mm2 ) from the multi b-value DWI. The contrast ratio of average intensity of the targeted lesions and the background PZ was determined. Receiver operator characteristic curves and the area under the curve (AUCs) were obtained for separating patients eligible for active surveillance with low risk prostate cancers from intermediate-high risk prostate cancers as per the cancer of the prostate risk assessment (CAPRA) scoring system. RESULTS: The AUC first increased then decreased with the increase in b-values reaching maximum at b = 1600 s/mm2 (0.74) with no statistically significant different AUC of DWI with b-values 1067-2000 s/mm2 . The AUC of computed DWI increased then decreased with the increase in b-values reaching a maximum of 0.75 around b = 2000 s/mm2 . There was no statistically significant difference between the AUC of optimal acquired DWI and either of optimal computed DWI. CONCLUSION: The optimal b-value for acquired DWI in differentiating intermediate-high from low risk prostate cancers in the PZ is b = 1600 s/mm2 . The computed DWI has similar performance as that of acquired DWI with the optimal performance around b = 2000 s/mm2 . LEVEL OF EVIDENCE: 4 J. Magn. Reson. Imaging 2017;45:125-131.

Does Abstinence From Ejaculation Before Prostate MRI Improve Evaluation of the Seminal Vesicles?

OBJECTIVE: The purpose of the present study is to determine whether abstinence from ejaculation before undergoing multiparametric prostate MRI increases seminal vesicle (SV) volume and therefore improves diagnostic interpretation of the SVs. MATERIALS AND METHODS: This retrospective study included 238 patients who underwent 3-T MRI of the prostate over a 4-month period. Patients were requested to complete a questionnaire that asked how long it had been since their last ejaculation (i.e., < 3 days vs ≥ 3 days). Forty-two patients (mean patient age, 62.0 years) indicated that it had been less than 3 days since their last ejaculation and were designated as group 1, whereas the remainder indicated an interval of 3 days or more since their last ejaculation. A group of 42 age-matched subjects (mean patient age, 62.1 years) were randomly selected from the remaining 196 patients and were designated as group 2. SV volumes were measured manually. Two radiologists who were blinded to group assignment and patient characteristics scored the right and left SVs separately to determine diagnostic interpretability, which was scored on a 3-point scale as follows: a score of 1 denoted that the SVs were not dilated and the score was nondiagnostic, a score of 2 indicated that the SVs were not dilated but the score was diagnostic, and a score of 3 denoted that the SVs were dilated and the score was diagnostic. Volume differences and interpretability scores were analyzed using a t test. Interobserver agreement was analyzed using the Cohen kappa statistic. A separate analysis was performed to evaluate differences in diagnostic interpretability for patients 60 years and younger versus patients older than 60 years, by use of the chi-square test and relative risk ratio analysis. RESULTS: The right, left, and total SV volumes for group 1 were 3.1 mL, 2.9 mL, and 6.0 mL, respectively, whereas those for group 2 were 4.7 mL, 4.1 mL, and 8.8 mL, respectively (p = 0.011). The mean interpretability scores for group 1 and group 2 were 2.0 and 2.5, respectively. For group 1, reader 1 and reader 2 assigned a nondiagnostic score for 10 and 13 patients, respectively, whereas for group 2, they assigned a nondiagnostic score for two and five patients, respectively (p = 0.01, for reader 1; and p = 0.03, for reader 2). For men in group 1 who were older than 60 years, reader 1 and reader 2 gave a nondiagnostic score for nine and 11 patients, respectively; whereas for men in group 2 who were older than 60 years, the readers gave a nondiagnostic score for two and five patients, respectively (p = 0.01, for reader 1; and p = 0.05, for reader 2). CONCLUSION: For men older than 60 years, abstinence from ejaculation for 3 or more days before undergoing MRI examination resulted in larger SV volumes and lower rates of nondiagnostic evaluation and therefore might improve evaluation of SV invasion on multi-parametric MRI. The difference is less striking in men 60 years and younger.

Application of an unsupervised multi-characteristic framework for intermediate-high risk prostate cancer localization using diffusion-weighted MRI.

PURPOSE: The aim of this proof-of-concept work is to propose an unsupervised framework that combines multiple parameters, in "positive-if-all-positive" manner, from different models to localize tumors. METHODS: A voxel-by-voxel analysis of the DW-MRI images of whole prostate was performed to obtain parametric maps for D*, D, f, and K using the IVIM and kurtosis models. Ten patients with moderate or high-risk prostate cancer were included in study. The mean age and serum PSA for these 10 patients were 65years (range 54-78) and 21.9ng/mL (range 4.84-44.81), respectively. These patients were scanned using a DW spin-echo sequence with echo-planar readout with 16 equidistantly spaced b-values in the range of 0-2000s/mm2 (TE=58ms; TR=3990ms; spatial resolution 2.19×2.19×2.73mm3, slices =26, FOV=140×140mm, slice gap =0.27mm, NSA=2). RESULTS: The proposed framework detected 24 lesions of which 14 were true positive with 58% tumor detection rate on lesion-based analysis with sensitivity of 100%. The mpMRI evaluation (PIRADSv2) identified 12 of 14 true positive lesions with sensitivity of 86%; positive predictive value of mpMRI was 92%. The index lesions were visible on all framework maps and were coded as the most suspicious in 9 of 10 patients. CONCLUSION: Preliminary results of the proposed framework indicate high patient-based sensitivity with 100% detection rate for identifying moderate-high risk aggressive index lesions.

A Phase I Dosing Study of Ferumoxytol for MR Lymphography at 3 T in Patients With Prostate Cancer.

OBJECTIVE: The objective of our study was to determine the optimal dose of ferumoxytol for performing MR lymphography (MRL) at 3 T in patients with prostate cancer. SUBJECTS AND METHODS: This phase I trial enrolled patients undergoing radical prostatectomy (RP) with bilateral pelvic lymph node dissection (PLND). Three groups of five patients each (total of 15 patients) received IV ferumoxytol before RP with bilateral PLND at each of the following doses of iron: 4, 6, and 7.5 mg Fe/kg. Patients underwent abdominopelvic MRI at 3 T before and 24 hours after ferumoxytol injection using T2- and T2*-weighted sequences. Normalized signal intensity (SI) and normalized SD changes from baseline to 24 hours after injection within visible lymph nodes were calculated for each dose level. Linear mixed effects models were used to estimate the effects of dose on the percentage SI change and log-transformed SD change within visible lymph nodes to determine the optimal dose of ferumoxytol for achieving uniform low SI in normal nodes. RESULTS: One patient who was excluded from the study group had a mild allergic reaction requiring treatment after approximately 2.5 mg Fe/kg ferumoxytol injection whereupon the injection was interrupted. The 15 study group patients tolerated ferumoxytol at all dose levels. The mean percentage SI change in 13 patients with no evidence of lymph metastasis was -36.4%, -45.4%, and -65.1% for 4, 6, and 7.5 mg Fe/kg doses, respectively (p = 0.041). CONCLUSION: A dose level of 7.5 mg Fe/kg ferumoxytol was safe and effective in deenhancing benign lymph nodes. This dose therefore can be the starting point for future phase II studies regarding the efficacy of ferumoxytol for MRL.

Comparison of calculated and acquired high b value diffusion-weighted imaging in prostate cancer.

PURPOSE: To determine whether the performance of calculated high b value diffusion-weighted images (DWI) derived from regular lower b value DWI using exponential diffusion decay models (intravoxel incoherent motion = IVIM and diffusional kurtosis = DK) is comparable to acquired high b value DWI in prostate cancer detection. MATERIALS AND METHODS: One hundred six patients underwent diagnostic multiparametric prostate MRI at 3T using an endorectal coil. Five b value (b = 0, 188, 375, 563, 750 s/mm(2)) DWI and high b value (b = 0, 1000 and 2000 s/mm(2)) DWI were acquired. Calculated high b value (b = 1000 s/mm(2) and b = 2000 s/mm(2)) DWI were derived from the DWI dataset using DK and IVIM models. Calculated and acquired high b value DWI images were compared for lesion visibility and image quality by two experienced radiologists (1 and 6 years of experience). GEE with Wald test was used to compare the image quality among the four calculated high b value DWI by comparing the proportion of lesions in each model which were comparable to the acquired images. This comparison was done for all lesions and by lesion location (PZ or CG; low apical/anterior or apical/mid/base) RESULTS: More lesions were visible on acquired b = 2000 s/mm(2) compared to b = 1000 s/mm(2) DWI. Calculated high b value DWI using the IVIM model had approximately the same number of lesions as acquired high b value DWI, whereas the DK model had fewer lesions than acquired images. The image quality of calculated high b value DWI was comparable to that of acquired images, and the highest quality images were obtained with b1000IVIM. The image quality of calculated b1000IVIM was the same as that of acquired DWI in apical/mid/base (98%) locations and comparable in low apical and anterior (95.4%) locations. The image quality of calculated b2000IVIM was inferior in both apical/mid/base (86.2%) locations and comparable in low apical and anterior (83.9%) locations. CONCLUSION: Calculated high b value DWI obtained using IVIM model has same lesion visibility as that of acquired DWI. The image quality of calculated high b value DWI relative to corresponding acquired DWI decreases with increase in b value.

Whole prostate volume and shape changes with the use of an inflatable and flexible endorectal coil.

Purpose. To determine to what extent an inflatable endorectal coil (ERC) affects whole prostate (WP) volume and shape during prostate MRI. Materials and Methods. 79 consecutive patients underwent T2W MRI at 3T first with a 6-channel surface coil and then with the combination of a 16-channel surface coil and ERC in the same imaging session. WP volume was assessed by manually contouring the prostate in each T2W axial slice. PSA density was also calculated. The maximum anterior-posterior (AP), left-right (LR), and craniocaudal (CC) prostate dimensions were measured. Changes in WP prostate volume, PSA density, and prostate dimensions were then evaluated. Results. In 79 patients, use of an ERC yielded no significant change in whole prostate volume (0.6 ± 5.7%, P = 0.270) and PSA density (-0.2 ± 5.6%, P = 0.768). However, use of an ERC significantly decreased the AP dimension of the prostate by -8.6 ± 7.8% (P < 0.001), increased LR dimension by 4.5 ± 5.8% (P < 0.001), and increased the CC dimension by 8.8 ± 6.9% (P < 0.001). Conclusion. Use of an ERC in prostate MRI results in the shape deformation of the prostate gland with no significant change in the volume of the prostate measured on T2W MRI. Therefore, WP volumes calculated on ERC MRI can be reliably used in clinical workflow.

Comparison of endorectal coil and nonendorectal coil T2W and diffusion-weighted MRI at 3 Tesla for localizing prostate cancer: correlation with whole-mount histopathology.

PURPOSE: To compare utility of T2-weighted (T2W) MRI and diffusion-weighted MRI (DWI-MRI) obtained with and without an endorectal coil at 3 Tesla (T) for localizing prostate cancer. MATERIALS AND METHODS: This Institutional Review Board-approved study included 20 patients (median prostate-specific antigen, 8.4 ng/mL). Patients underwent consecutive prostate MRIs at 3T, first with a surface coil alone, then with combination of surface, endorectal coils (dual coil) followed by robotic assisted radical prostatectomy. Lesions were mapped at time of acquisition on dual-coil T2W, DWI-MRI. To avoid bias, 6 months later nonendorectal coil T2W, DWI-MRI were mapped. Both MRI evaluations were performed by two readers blinded to pathology with differences resolved by consensus. A lesion-based correlation with whole-mount histopathology was performed. RESULTS: At histopathology 51 cancer foci were present ranging in size from 2 to 60 mm. The sensitivity of the endorectal dual-coil, nonendorectal coil MRIs were 0.76, 0.45, respectively. PPVs for endorectal dual-coil, nonendorectal coil MRI were 0.80, 0.64, respectively. Mean size of detected lesions with nonendorectal coil MRI were larger than those detected by dual-coil MRI (22 mm versus 17.4 mm). CONCLUSION: Dual-coil prostate MRI detected more cancer foci than nonendorectal coil MRI. While nonendorectal coil MRI is an attractive alternative, physicians performing prostate MRI should be aware of its limitations.

Fully automated prostate segmentation on MRI: comparison with manual segmentation methods and specimen volumes.

OBJECTIVE: The objective of our study was to compare calculated prostate volumes derived from tridimensional MR measurements (ellipsoid formula), manual segmentation, and a fully automated segmentation system as validated by actual prostatectomy specimens. MATERIALS AND METHODS: Ninety-eight consecutive patients (median age, 60.6 years; median prostate-specific antigen [PSA] value, 6.85 ng/mL) underwent triplane T2-weighted MRI on a 3-T magnet with an endorectal coil while undergoing diagnostic workup for prostate cancer. Prostate volume estimates were determined using the formula for ellipsoid volume based on tridimensional measurements, manual segmentation of triplane MRI, and automated segmentation based on normalized gradient fields cross-correlation and graph-search refinement. Estimates of prostate volume based on ellipsoid volume, manual segmentation, and automated segmentation were compared with prostatectomy specimen volumes. Prostate volume estimates were compared using the Pearson correlation coefficient and linear regression analysis. The Dice similarity coefficient was used to quantify spatial agreement between manual segmentation and automated segmentation. RESULTS: The Pearson correlation coefficient revealed strong positive correlation between prostatectomy specimen volume and prostate volume estimates derived from manual segmentation (R = 0.89-0.91, p < 0.0001) and automated segmentation (R = 0.88-0.91, p < 0.0001). No difference was observed between manual segmentation and automated segmentation. Mean partial and full Dice similarity coefficients of 0.92 and 0.89, respectively, were achieved for axial automated segmentation. CONCLUSION: Prostate volume estimates obtained with a fully automated 3D segmentation tool based on normalized gradient fields cross-correlation and graph-search refinement can yield highly accurate prostate volume estimates in a clinically relevant time of 10 seconds. This tool will assist in developing a broad range of applications including routine prostate volume estimations, image registration, biopsy guidance, and decision support systems.

Prostate cancer: can multiparametric MR imaging help identify patients who are candidates for active surveillance?

PURPOSE: To determine whether multiparametric magnetic resonance (MR) imaging can help identify patients with prostate cancer who would most appropriately be candidates for active surveillance (AS) according to current guidelines and to compare the results with those of conventional clinical assessment scoring systems, including the D'Amico, Epstein, and Cancer of the Prostate Risk Assessment (CAPRA) systems, on the basis of findings at prostatectomy. MATERIALS AND METHODS: This institutional review board-approved HIPAA-compliant retrospectively designed study included 133 patients (mean age, 59.3 years) with a mean prostate-specific antigen level of 6.73 ng/mL (median, 4.39 ng/mL) who underwent multiparametric MR imaging at 3.0 T before radical prostatectomy. Informed consent was obtained from all patients. Patients were then retrospectively classified as to whether they would have met AS eligibility criteria or were better served by surgery. AS eligibility criteria for prostatectomy specimens were a dominant tumor smaller than 0.5 mL without Gleason 4 or 5 patterns or extracapsular or seminal vesicle invasion. Conventional clinical assessment scores (the D'Amico, Epstein, and CAPRA scoring systems) were compared with multiparametric MR imaging findings for predicting AS candidates. The level of significance of difference between scoring systems was determined by using the χ(2) test for categoric variables with the level of significance set at P < .05. RESULTS: Among 133 patients, 14 were eligible for AS on the basis of prostatectomy results. The sensitivity, positive predictive value (PPV), and overall accuracy, respectively, were 93%, 25%, and 70% for the D'Amico system, 64%, 45%, and 88% for the Epstein criteria, and 93%, 20%, and 59% for the CAPRA scoring system for predicting AS candidates (P < .005 for all, χ(2) test), while multiparametric MR imaging had a sensitivity of 93%, a PPV of 57%, and an overall accuracy of 92% (P < .005). CONCLUSION: Multiparametric MR imaging provides useful additional information to existing clinicopathologic scoring systems of prostate cancer and improves the assignment of treatment (eg, AS or active treatment).

Correlation of magnetic resonance imaging tumor volume with histopathology.

PURPOSE: The biology of prostate cancer may be influenced by the index lesion. The definition of index lesion volume is important for appropriate decision making, especially for image guided focal treatment. We determined the accuracy of magnetic resonance imaging for determining index tumor volume compared with volumes derived from histopathology. MATERIALS AND METHODS: We evaluated 135 patients (mean age 59.3 years) with a mean prostate specific antigen of 6.74 ng/dl who underwent multiparametric 3T endorectal coil magnetic resonance imaging of the prostate and subsequent radical prostatectomy. Index tumor volume was determined prospectively and independently by magnetic resonance imaging and histopathology. The ellipsoid formula was applied to determine histopathology tumor volume, whereas manual tumor segmentation was used to determine magnetic resonance tumor volume. Histopathology tumor volume was correlated with age and prostate specific antigen whereas magnetic resonance tumor volume involved Pearson correlation and linear regression methods. In addition, the predictive power of magnetic resonance tumor volume, prostate specific antigen and age for estimating histopathology tumor volume (greater than 0.5 cm(3)) was assessed by ROC analysis. The same analysis was also conducted for the 1.15 shrinkage factor corrected histopathology data set. RESULTS: There was a positive correlation between histopathology tumor volume and magnetic resonance tumor volume (Pearson coefficient 0.633, p <0.0001), but a weak correlation between prostate specific antigen and histopathology tumor volume (Pearson coefficient 0.237, p = 0.003). On linear regression analysis histopathology tumor volume and magnetic resonance tumor volume were correlated (r(2) = 0.401, p <0.00001). On ROC analysis AUC values for magnetic resonance tumor volume, prostate specific antigen and age in estimating tumors larger than 0.5 cm(3) at histopathology were 0.949 (p <0.0000001), 0.685 (p = 0.001) and 0.627 (p = 0.02), respectively. Similar results were found in the analysis with shrinkage factor corrected tumor volumes at histopathology. CONCLUSIONS: Magnetic resonance imaging can accurately estimate index tumor volume as determined by histology. Magnetic resonance imaging has better accuracy in predicting histopathology tumor volume in tumors larger than 0.5 cm(3) than prostate specific antigen and age. Index tumor volume as determined by magnetic resonance imaging may be helpful in planning treatment, specifically in identifying tumor margins for image guided focal therapy and possibly selecting better active surveillance candidates.

11C-Acetate PET/CT in localized prostate cancer: a study with MRI and histopathologic correlation.

UNLABELLED: This work characterizes the uptake of (11)C-acetate in prostate cancer (PCa), benign prostate hyperplasia, and normal prostate tissue in comparison with multiparametric MRI, whole-mount histopathology, and clinical markers to evaluate the potential utility of (11)C-acetate for delineating intraprostatic tumors in a population of patients with localized PCa. METHODS: Thirty-nine men with presumed localized PCa underwent dynamic-static abdominal-pelvic (11)C-acetate PET/CT for 30 min and 3-T multiparametric MRI before prostatectomy. PET/CT images were registered to MR images using pelvic bones for initial rotation-translation, followed by manual adjustments to account for prostate motion and deformation from the MRI endorectal coil. Whole-mount pathology specimens were sectioned using an MRI-based patient-specific mold resulting in improved registration between the MRI, PET, and pathology. (11)C-acetate PET standardized uptake values were compared with multiparametric MRI and pathology. RESULTS: (11)C-acetate uptake was rapid but reversible, peaking at 3-5 min after injection and reaching a relative plateau at approximately 10 min. The average maximum standardized uptake value (10-12 min) of tumors was significantly higher than that of normal prostate tissue (4.4 ± 2.05 [range, 1.8-9.2] vs. 2.1 ± 0.94 [range, 0.7-3.4], respectively; P < 0.001); however, it was not significantly different from that of benign prostatic hyperplasia (4.8 ± 2.01 [range, 1.8-8.8]). A sector-based comparison with histopathology, including all tumors greater than 0.5 cm, revealed a sensitivity and specificity of 61.6% and 80.0%, respectively, for (11)C-acetate PET/CT and 82.3% and 95.1%, respectively, for MRI. The (11)C-acetate accuracy was comparable to that of MRI when only tumors greater than 0.9 cm were considered. In a small cohort (n = 9), (11)C-acetate uptake was independent of fatty acid synthase expression using immunohistochemistry. CONCLUSION: (11)C-acetate PET/CT demonstrates higher uptake in tumor foci than in normal prostate tissue; however, (11)C-acetate uptake in tumors is similar to that in benign prostate hyperplasia nodules. Although (11)C-acetate PET/CT is not likely to have utility as an independent modality for evaluation of localized PCa, the high uptake in tumors may make it useful for monitoring focal therapy when tissue damage after therapy may limit anatomic imaging methods.

Multiparametric 3T prostate magnetic resonance imaging to detect cancer: histopathological correlation using prostatectomy specimens processed in customized magnetic resonance imaging based molds.

PURPOSE: We determined the prostate cancer detection rate of multiparametric magnetic resonance imaging at 3T. Precise one-to-one histopathological correlation with magnetic resonance imaging was possible using prostate magnetic resonance imaging based custom printed specimen molds after radical prostatectomy. MATERIALS AND METHODS: This institutional review board approved prospective study included 45 patients (mean age 60.2 years, range 49 to 75) with a mean prostate specific antigen of 6.37 ng/ml (range 2.3 to 23.7) who had biopsy proven prostate cancer (mean Gleason score of 6.7, range 6 to 9). Before prostatectomy all patients underwent prostate magnetic resonance imaging using endorectal and surface coils on a 3T scanner, which included triplane T2-weighted magnetic resonance imaging, apparent diffusion coefficient maps of diffusion weighted magnetic resonance imaging, dynamic contrast enhanced magnetic resonance imaging and spectroscopy. The prostate specimen was whole mount sectioned in a customized mold, allowing geometric alignment to magnetic resonance imaging. Tumors were mapped on magnetic resonance imaging and histopathology. Sensitivity, specificity, positive predictive value and negative predictive value of magnetic resonance imaging for cancer detection were calculated. In addition, the effects of tumor size and Gleason score on the sensitivity of multiparametric magnetic resonance imaging were evaluated. RESULTS: The positive predictive value of multiparametric magnetic resonance imaging to detect prostate cancer was 98%, 98% and 100% in the overall prostate, peripheral zone and central gland, respectively. The sensitivity of magnetic resonance imaging sequences was higher for tumors larger than 5 mm in diameter as well as for those with higher Gleason scores (greater than 7, p <0.05). CONCLUSIONS: Prostate magnetic resonance imaging at 3T allows for the detection of prostate cancer. A multiparametric approach increases the predictive power of magnetic resonance imaging for diagnosis. In this study accurate correlation between multiparametric magnetic resonance imaging and histopathology was obtained by the patient specific, magnetic resonance imaging based mold technique.