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Prostate MRI is now established as a first-line investigation for individuals presenting with suspected localized or locally advanced prostate cancer. Successful delivery of the MRI-directed pathway for prostate cancer diagnosis relies on high-quality imaging as well as the interpreting radiologist's experience and expertise. Radiologist certification in prostate MRI may help limit interreader variability, optimize outcomes, and provide individual radiologists with documentation of meeting predefined standards. This AJR Expert Panel Narrative Review summarizes existing certification proposals, recognizing variable progress across regions in establishing prostate MRI certification programs. To our knowledge, Germany is the only country with a prostate MRI certification process that is currently available for radiologists. However, prostate MRI certification programs have also recently been proposed in the United States and United Kingdom and by European professional society consensus panels. Recommended qualification processes entail a multifaceted approach, incorporating components such as minimum case numbers, peer learning, course participation, continuing medical education credits, and feedback from pathology results. Given the diversity in health care systems, including in the provision and availability of MRI services, national organizations will likely need to take independent approaches to certification and accreditation. The relevant professional organizations should begin developing these programs or continue existing plans for implementation.

Prostate cancer is the second most common malignancy in men worldwide. Systematic transrectal prostate biopsy is commonly used to obtain tissue to establish the diagnosis. In recent years, however, more clinically significant cancer and less clinically insignificant cancer have been detected with MRI targeted biopsy (on the basis of an MRI examination performed before consideration of biopsy) than with systematic biopsy. This approach of performing MRI before biopsy has become, or is becoming, a standard of practice in centers throughout the world. This growing use of an MRI-directed pathway is leading to performance of a larger volume of MRI targeted prostate biopsies. The three common MRI targeted biopsy techniques are cognitive biopsy, MRI-ultrasound software fusion biopsy, and MRI in-bore guided biopsy. These techniques for using MRI information at biopsy can be performed via a transrectal or transperineal approach. The purpose of this review is to describe the three MRI targeted biopsy techniques and their advantages and shortcomings. Comparisons among the techniques are summarized on the basis of the available evidence. Studies to date have had heterogeneous results, and the preferred technique remains debated.

PI-RADS version 2.1 updates the technical parameters for multiparametric MRI (mpMRI) of the prostate and revises the imaging interpretation criteria while maintaining the framework introduced in version 2. These changes have been considered an improvement, although some issues remain unresolved, and new issues have emerged. Areas for improvement discussed in this review include the need for more detailed mpMRI protocols with optimization for 1.5-T and 3-T systems; lack of validation of revised transition zone interpretation criteria and need for clarifications of the revised DWI and dynamic contrast-enhanced imaging criteria and central zone (CZ) assessment; the need for systematic evaluation and reporting of background changes in signal intensity in the prostate that can negatively affect cancer detection; creation of a new category for lesions that do not fit into the PI-RADS assessment categories (i.e., PI-RADS M category); inclusion of quantitative parameters beyond size to evaluate lesion aggressiveness; adjustments to the structured report template, including standardized assessment of the risk of extraprostatic extension; development of parameters for image quality and performance control; and suggestions for expansion of the system to other indications (e.g., active surveillance and recurrence).

Objective: The purpose of this study was to evaluate the diagnostic performance of the Prostate Imaging Reporting and Data System version 2 (PI-RADSv2) with respect to prebiopsy MRI with and without dynamic contrast enhancement in the detection of clinically significant cancer (CSC)., Materials and Methods: A total of 113 patients with prostate cancer who underwent radical prostatectomy and prebiopsy multiparametric 3-T MRI (mpMRI) that included T2-weighted imaging, DWI, and dynamic contrast-enhanced MRI (DCE-MRI) were enrolled in a retrospective study conducted at two institutions. For detecting CSC at prebiopsy mpMRI with DCE-MRI and biparametric MRI (bpMRI) without DCE-MRI, two independent radiologists using PI-RADSv2 scored suspicious lesions in all patients., Results: CSC was identified in 74.3% (84/113) of patients. For CSC detection rate, no statistical differences between bpMRI and mpMRI were found for any PI-RADS score (p > 0.05). For cancer in the peripheral zone, reader 1 upgraded 22 lesions and reader 2 upgraded 13 lesions from PI-RADS score 3 at bpMRI to PI-RADS 4 (3 + 1) at mpMRI. The CSC detection rate of PI-RADS 3 + 1 lesions at mpMRI (reader 1, 63.6%; reader 2, 69.2%) was slightly greater than that of PI-RADS 3 lesions at bpMRI (reader 1, 53.8%; reader 2, 60.0%), which was not statistically different (p > 0.05). Interreader agreement on PI-RADS scoring was moderate for both bpMRI (κ = 0.540) and mpMRI (κ = 0.478)., Conclusion: For detecting CSC, the diagnostic performance of prebiopsy bpMRI without DCE-MRI is similar to that of mpMRI with DCE-MRI.

Objective: The purpose of this study is to investigate the rates and characteristics of missed cancers at prebiopsy multiparametric MRI with cancer-negative findings according to the Prostate Imaging Reporting and Data System (PI-RADS) version 2 in men with suspected prostate cancer (PCa)., Materials and Methods: A total of 584 consecutive men (biopsy naive, n = 392; repeated biopsy, n = 192) with suspected PCa who underwent prebiopsy 3-T multipara-metric MRI, followed by subsequent biopsies, were enrolled. Cancer-positive findings were confirmed at systemic biopsies and cognitive MRI-targeted biopsies, whereas cancer-negative findings were confirmed at systemic biopsies performed during subsequent follow-up. Missing and detection rates of all PCa and clinically significant cancer according to five biopsy-based definitions were determined. The likelihood of PCa at multiparametric MRI was evaluated according to PI-RADS version 2, and the results were compared., Results: Pathologically confirmed cancers were found in 25% of patients. Cancer-positive MRI findings were seen in 99 men (17%) and, of these, 85.9% had PCa. Of 485 men with cancer-negative MRI findings, a total of 61 (12.6%) had PCa, including 46 men in the biopsy-naive group and 15 men in the repeated-biopsy group. For clinically significant cancers, the rate of missed cancers at MRI was 0.1-6.0%, and the detection rate was 21.2-83.5%. For detecting PCa, multiparametric MRI had 96.8% specificity, 87.2% accuracy, and 87.4% negative predictive value., Conclusion: Prebiopsy 3-T multiparametric MRI with cancer-negative findings missed approximately 12.6% of cases of PCa, including 0.1-6.0% of clinically significant cancers in a cohort of biopsy-naive men and those who had undergone repeated biopsy.

Objective: The purpose of this study was to retrospectively investigate the utility of multiparametric MRI in differentiating minimal-fat angiomyolipoma (AML) from renal cell carcinoma (RCC) in small renal tumors with predominantly low signal intensity on T2-weighted MR images., Materials and Methods: Fifty-six patients with pathologically identified renal tumors (1-4 cm) with predominantly low signal intensity on T2-weighted images without visible fat on unenhanced CT images were enrolled. Clinical and MRI variables (tumor-to-renal cortex signal intensity [SI] ratio on T2-weighted images [T2 ratio], apparent diffusion coefficient [ADC], and SI index) on chemical-shift images were evaluated., Results: The ADC was significantly lower in RCC than in minimal-fat AML (p = 0.001). The T2 ratio and signal intensity index were not significantly different between RCC (p = 0.31) and minimal-fat AML (p = 0.74). Multivariate analysis showed that ADC (odds ratio [OR], 0.01; p = 0.02) and male sex (OR, 46.7; p < 0.001) were the independent predictors of RCC. For differentiating minimal-fat AML from RCC, the ROC AUC of ADC was 0.781. When ADC and sex were combined, the AUC significantly increased to 0.937 with a cutoff value of 1.129 × 10 -3 mm 2 /s. For making the diagnosis of minimal-fat AML if the ADC was greater than the threshold, sensitivity was 89.7% and specificity was 88.2% (p = 0.02)., Conclusion: In small renal tumors with predominantly low SI on T2-weighted images, ADC is useful for differentiating minimal-fat AML from RCC. Combining ADC with male sex increases the accuracy of RCC prediction.

Objective: The purpose of this study was to evaluate the diagnostic accuracy and safety of ultrasound (US)-guided transvaginal core biopsy of pelvic masses., Materials and Methods: Fifty-five pelvic masses in 55 consecutive women who underwent US-guided transvaginal core biopsy were enrolled in our study. All lesions were detected on CT or MRI before biopsy. The procedure was performed with local anesthesia using a transvaginal US probe equipped with a guide and an 18-gauge needle with an automatic biopsy gun. We evaluated the diagnostic accuracy and complication rate of the procedure., Results: All acquired specimens were adequate for the histopathologic analysis. The overall diagnostic accuracy of US-guided transvaginal core biopsy was 93% (51/55). Of the 55 lesions, 46 (84%) were confirmed to be either benign or malignant tumors, and five (9%) were diagnosed as active or chronic inflammatory lesions. Four lesions (7%) were not histopathologically diagnosed after biopsy: two were confirmed as fibrothecoma and leiomyosarcoma after surgery, and the remaining two were clinically determined to be recurrent cancer. In terms of minor complications, vaginal bleeding occurred in 10 patients (18%), and gross hematuria occurred in two patients (4%). These complications resolved spontaneously in all patients without further workup or treatment., Conclusion: US-guided transvaginal core biopsy seems to be safe and reliable procedure for the histopathologic diagnosis of pelvic masses.

Objective: The objective of our study was to determine unenhanced CT and MRI parameters that can be used to reliably predict fat-invisible angiomyolipoma (AML)., Materials and Methods: A total of 152 patients with 155 histologically proven renal cell carcinomas (RCCs) and 16 patients with 18 histologically proven AMLs were included. No AML measured less than -20 HU on CT images. The tumor-to-cortex ratio was measured on unenhanced CT, T2-weighted MRI, and T1-weighted MRI to compare fat-invisible AML and RCC. On chemical-shift MRI, the signal intensity (SI) index and tumor-to-spleen ratio were calculated to compare these lesions. The unpaired t test and ROC with AUC were used for statistical analysis. The reference standard was pathologic examination., Results: The mean tumor-to-cortex ratios on unenhanced CT of AML and RCC were 1.37 ± 0.66 (SD) and 0.83 ± 0.47, respectively (p < 0.001). However, the tumor-to-cortex ratio on unenhanced CT of AML was not different from that of chromophobe RCC (p = 0.093). The mean tumor-to-cortex ratios on T2-weighted MRI of AML and RCC were 0.75 ± 0.15 and 1.21 ± 0.41, respectively (p < 0.001). However, the tumor-to-cortex ratio on T2-weighted MRI of AML was not different from that of papillary RCC (p = 0.161). The tumor-to-spleen ratio on chemical-shift MRI, tumor-to-cortex ratio on T1-weighted MRI, and SI index on chemical-shift MRI of AML were not different from those of RCC (p = 0.104-0.670). The AUCs of the tumor-to-cortex ratio on T2-weighted MRI and the tumor-to-cortex ratio on unenhanced CT were 0.862 and 0.835, respectively., Conclusion: The tumor-to-cortex ratio on T2-weighted MRI and the tumor-to-cortex ratio on unenhanced CT are good parameters to differentiate fat-invisible AML from clear cell RCC. Nevertheless, percutaneous biopsy is necessary because these parameters are not reliable in differentiating fat-invisible AML from non-clear cell RCC.

Objective: The purpose of this study was to quantitatively differentiate adrenal hyperplasia from adenoma with the use of adrenal CT protocols., Materials and Methods: Between January 2004 and November 2012, a total of 156 patients (69 men and 87 women; mean age, 48.9 years) underwent unenhanced CT, early contrast-enhanced CT, and delayed contrast-enhanced CT before undergoing adrenalectomy. Of these patients, 142 had 144 adenomas and 14 had nodular (n = 12) or diffuse (n = 2) hyperplasia. An ROI was placed on 144 adenomas and 27 hyperplastic nodules that were 1 cm or larger or on the four thickest areas of both adrenal glands. The number of each type of lesion and the attenuation value, absolute percentage washout (APW), and relative percentage washout (RPW) associated with hyperplasia and adenoma were compared. The reference standard was pathologic examination. A mixed model and the Fisher exact test were used for statistical analysis., Results: On unenhanced CT, the mean (± SD) attenuation value for hyperplasia and adenoma was 18.8 ± 10.8 HU and 13.7 ± 15.6 HU, respectively (p = 0.375). When a threshold of 10 HU or lower was used, 22.6% of hyperplastic lesions (7/31) were misdiagnosed as adenomas. The mean APW associated with hyperplasia and adenoma was 73.7% ± 9.3% and 67.3% ± 26.2%, respectively (p = 0.449), whereas the mean RPW for hyperplasia and adenoma was 61.2% ± 9.2% and 59.9% ± 23.0%, respectively (p = 0.625). When an APW threshold of 60% or higher or an RPW threshold of 40% or higher was used, 100% of hyperplastic lesions (31/31) were misdiagnosed as adenoma. Three or more nodules were detected in 33.3% of patients with nodular hyperplasia (4/12) but in none of the patients with adenoma (p < 0.001)., Conclusion: Adrenal hyperplasia cannot be quantitatively differentiated from adenoma because there is significant overlap in findings from CT densitometry and assessment of percentage washout. However, the presence of three or more nodules increases the likelihood of nodular hyperplasia.

Objective: The purpose of this study was to investigate the utility of diffusion-weighted MRI (DWI) at 3 T for assessing renal function impairment in patients with liver cirrhosis., Materials and Methods: Sixty-four patients with liver cirrhosis who underwent both DWI at 3 T and renal function testing were retrospectively included. Twenty-two patients had moderate or severe renal function impairment (group A, estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m(2)) and 42 had good renal function or mild renal function impairment (group B, eGFR ≥ 60 mL/min/1.73 m(2)). Cortical and medullary apparent diffusion coefficients (ADCs) of both kidneys were measured. AUC was assessed for predicting group A with ADC. The correlation between renal ADC and eGFR or serum creatinine was analyzed. The reproducibility of ADC measurement was investigated., Results: Both cortical and medullary ADCs were lower in group A than in group B, (both, p < 0.05). In all patients, AUCs were 0.784 and 0.737 with cortical and medullary ADCs, respectively, for predicting group A. Both cortical and medullary ADCs had linear correlation with eGFR or serum creatinine (both, p < 0.05). The reproducibility of measurement was excellent for cortex (intraclass coefficient [ICC] = 0.808) and good for medulla (ICC = 0.692), with 1.6% or less variability., Conclusion: DWI may have potential for assessing renal function impairment in patients with liver cirrhosis.

Objective: The objective of our study was to investigate the usefulness of apparent diffusion coefficient (ADC) values in evaluating for therapeutic changes from androgen deprivation therapy (ADT) in prostate cancer patients., Materials and Methods: Forty-eight patients with prostate cancer treated with ADT were enrolled in this retrospective study. Diffusion-weighted imaging (DWI) at 3 T was performed before and after ADT. Before and after treatment, ADC values were measured in the tumors and in the benign tissues of the prostate, and serum prostate-specific antigen (PSA) levels and prostate volumes were also assessed. Statistical analysis was performed using a paired Student t test, Wilcoxon signed rank test, and Spearman rank correlation., Results: In 48 patients, 55 tumors were identified. After treatment, the mean ADC value of the tumors (1.06×10(-3) mm2/s) was significantly increased as compared with the pretreatment value (0.78×10(-3) mm2/s) (p<0.001), whereas the ADC values of the benign tissues after treatment were significantly decreased compared with the pretreatment values (p<0.001). The mean prostate volume and mean PSA level were significantly reduced from 42.8 cm3 and 153.60 ng/mL before treatment to 21.4 cm3 and 9.51 ng/mL, respectively, after treatment (p<0.001). Changes in tumor ADC values showed a weak negative correlation with changes in PSA levels after treatment (correlation coefficient, ρ=-0.320; p=0.028)., Conclusion: DWI may have potential as a noninvasive tool for monitoring changes in response to ADT in prostate cancer patients.

Objective: The purpose of this study was to prospectively evaluate the reliability and variability of apparent diffusion coefficient (ADC) calculations between two-point and multipoint b value analyses in prostate cancer and benign prostate tissue., Subjects and Methods: Forty-eight consecutive patients with suspected prostate cancer underwent diffusion-weighted MRI (DWI) at 3 T followed by surgery. DWI was examined under different b values. ADC maps were generated by two different methods: two-point b values (0 and 1000 s/mm(2)) and multipoint b values (0, 100, 300, 700, and 1000 s/mm(2)). Two independent readers measured ADC in the cancers, benign peripheral zone and transition zone, and obturator internus muscle. Statistical analyses were performed using the intraclass correlation coefficient (ICC), correlation of variation (CV), Bland-Altman test, and paired Student t test., Results: The intermethod ADC calculation revealed excellent reliability for all tissues in both readers: cancer (ICC = 0.979-0.981), transition zone (0.989-0.993), peripheral zone (0.990-0.994), and obturator internus muscle (0.967-0.975). In both readers, the variability of the intermethod ADC calculation was 2.90-3.09% CV in cancer, 1.16-1.48% CV in the transition zone, 1.03-1.29% CV in the peripheral zone, and 2.44-2.62% CV in the obturator internus muscle. For interreader variability, the CVs of ADC calculation for two-point versus multipoint b value analyses in all tissues were 7.21-9.65% versus 7.18-9.01%., Conclusion: For estimating ADC values on 3-T DWI of the prostate, two-point b value analysis seems to present excellent correlation with multipoint b value analysis, with little error in accuracy.

Objective: The purpose of this article is to retrospectively evaluate the impact of prebiopsy MRI on preoperative assessment of prostate cancer., Materials and Methods: Between January 2005 and June 2012, 89 patients (mean age, 64 years; range, 50-77 years) underwent prebiopsy MRI, transrectal ultrasound-guided biopsy, and prostatectomy for adenocarcinoma. On MR images, prostate cancer was diagnosed if T2-weighted images, diffusion-weighted images, and dynamic contrast-enhanced images were all positive. Preoperative cancers were classified as low, intermediate, high, and very high risk using prostate-specific antigen (PSA) level, biopsy Gleason score, or MRI tumor stage. Postoperative cancers were classified as low, intermediate, high, and very high risk using PSA level, prostatectomy Gleason score, and prostatectomy tumor stage. Interrater agreement using weighted kappa values was used to compare the paired data., Results: Preoperative cancers assessed by PSA level alone and postoperative cancers were concordant in 24.7% (22/89) and discordant in 75.3% (67/89) of cases, with poor agreement (weighted κ, 0.13; 95% CI, 0.05-0.21). Preoperative cancers assessed by biopsy Gleason score alone and postoperative cancers were concordant in 40.4% (36/89) and discordant in 59.6% (53/89) of cases, with fair agreement (weighted κ, 0.22; 95% CI, 0.09-0.36). Preoperative cancers assessed by MRI tumor stage alone and postoperative cancers were concordant in 74.2% (66/89) and discordant in 25.8% (23/89) of cases, with moderate agreement (weighted κ, 0.54; 95% CI, 0.38-0.71)., Conclusion: Prebiopsy MRI may provide better information on preoperative assessment of prostate cancer than PSA level and biopsy Gleason score.

Objective: The purpose of this article is to evaluate the utility of diffusion-weighted imaging (DWI) and blood oxygenation level-dependent (BOLD) MRI for characterizing renal cell carcinoma (RCC) subtypes at 3 T., Materials and Methods: Seventy-seven patients underwent 3-T DWI and BOLD MRI. Apparent diffusion coefficient (ADC; × 10(-3) mm(2)/s) and rate of spin dephasing (R2*, which equals 1 / T2* relaxation time, or 1/s) values were measured in the three RCC subtypes and normal renal parenchyma, and the results were compared. Statistical analyses were performed using analysis of variance, Student t test, and ROC curve analysis., Results: Clear cell RCCs showed statistically significantly greater ADC values (1.81 × 10(-3) mm(2)/s) than did papillary (1.29 × 10(-3) mm(2)/s) and chromophobe (1.55 × 10(-3) mm(2)/s) RCCs (p < 0.01); however, no statistically significant differences between papillary and chromophobe RCCs were observed (p = 0.26). Chromophobe RCCs showed the greatest mean R2* (33.6 1/s) of the three subtypes (p < 0.01); however, no statistically significant differences between clear cell RCCs and papillary RCCs were seen (p = 0.48). Low-grade clear cell RCCs showed statistically significantly higher ADC value (1.97 × 10(-3) mm(2)/s) than did high-grade clear cell RCCs (1.66 × 10(-3) mm(2)/s; p = 0.021). For differentiating clear cell RCCs from non-clear cell RCCs, the AUCs of ADC and R2* values were 0.756 × 10(-3) mm(2)/s and 0.607 (1/s), respectively (p = 0.047): cutoff values of ADC (1.4 × 10(-3) mm(2)/s) and R2* (26.3 1/s) resulted in sensitivities and specificities of 85% and 73%, and 86% and 47%, respectively., Conclusion: For characterizing RCC subtypes, DWI and BOLD MRI at 3 T may be useful, but the current technique of BOLD MRI seems to have a limited diagnostic accuracy.

Objective: The purpose of this study is to retrospectively investigate whether pretreatment multiparametric MRI findings can predict biochemical recurrence in patients who underwent radical prostatectomy (RP) for localized prostate cancer., Materials and Methods: In this study, 282 patients with biopsy-proven prostate cancer who received RP underwent pretreatment MRI using a phased-array coil at 3 T, including T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and dynamic contrast-enhanced MRI (DCE-MRI). MRI variables included apparent tumor presence on combined imaging sequences, extracapsular extension, and tumor size on DWI or DCE-MRI. Clinical variables included baseline prostate-specific antigen (PSA) level, clinical stage, and Gleason score at biopsy. The relationship between clinical and imaging variables and biochemical recurrence was evaluated using Cox regression analysis., Results: After a median follow-up of 26 months, biochemical recurrence developed in 61 patients (22%). Univariate analysis revealed that all the imaging and clinical variables were significantly associated with biochemical recurrence (p < 0.01). On multivariate analysis, however, baseline PSA level (p = 0.002), Gleason score at biopsy (p = 0.024), and apparent tumor presence on combined T2WI, DWI, and DCE-MRI (p = 0.047) were the only significant independent predictors of biochemical recurrence. Of the independent predictors, apparent tumor presence on combined T2WI, DWI, and DCE-MRI showed the highest hazard ratio (2.38) compared with baseline PSA level (hazard ratio, 1.05) and Gleason score at biopsy (hazard ratio, 1.34)., Conclusion: The apparent tumor presence on combined T2WI, DWI, and DCE-MRI of pretreatment MRI is an independent predictor of biochemical recurrence after RP. This finding may be used to construct a predictive model for biochemical recurrence after surgery.

Objective: The purpose of this article is to retrospectively compare the accuracy of MRI and CT in characterizing lipid-poor adrenal adenomas with respect to lesion-attenuation values measured on unenhanced CT., Materials and Methods: Fifty-two lipid-poor adrenal masses measuring greater than 10 HU on unenhanced CT were identified in 52 patients who underwent both chemical-shift MRI and washout CT. Accuracies using the adrenal-to-spleen ratio (< 0.71) or signal intensity index (> 16.5%) for MRI and using absolute (≥ 60%) or relative (≥ 40%) percentage washout for CT were calculated to determine which modality was more accurate for lipid-poor adenoma characterization. Sensitivities of MRI and CT were also compared according to the lesion-attenuation values measured on unenhanced CT. Follow-up imaging or histologic diagnosis was used as the standard reference. The McNemar test was used to compare the accuracies of CT and MRI., Results: Lipid-poor adrenal masses consisted of 37 adenomas and 15 nonadenomas. The sensitivities and specificities for adenoma on MRI versus CT were 75.7% (28/37) versus 100% (37/37) and 60.0% (9/15) versus 80.0% (12/15), respectively. CT achieved a higher accuracy than did MRI (p = 0.008). The sensitivities for adenomas measuring 20 HU or less on unenhanced CT were 100% (12/12) in both MRI and CT, whereas those measuring more than 20 HU were 64.0% (16/25) and 100% (25/25) in MRI and CT, respectively., Conclusion: MRI is equivalent to CT for characterizing adenomas measuring 20 HU or less on unenhanced CT. However, MRI is inferior to CT for adenomas measuring more than 20 HU because of decreased MR sensitivity.

Objective: The purpose of this study was to retrospectively investigate the value of adding diffusion-weighted imaging (DWI) to T2-weighted imaging for the prediction of extracapsular extension (ECE) in patients with prostate cancer, as well as to compare apparent diffusion coefficients (ADCs) between patients with and without ECE., Materials and Methods: Seventy-six patients with suspected prostate cancer underwent T2-weighted imaging and DWI at 3 T using a phased-array coil, followed by radical prostatectomy. For prediction of ECE, the prostate was divided into six sectors. Two experienced radiologists analyzed T2-weighted images alone and in combination with DWI in consensus and rated the likelihood of ECE on a five-point scale. Tumor ADC values were measured, and the results were compared between patients with and without ECE., Results: Of the 456 sectors studied, 74 (16%) were positive for ECE in 31 patients. For prediction of ECE, the specificity and accuracy of combined T2-weighted imaging and DWI were 94.5% and 91.7%, respectively, superior to those of T2-weighted imaging alone (87.2% and 81.2%, respectively) (p < 0.001). On receiver operating characteristic analysis, the area under the curve (Az) of combined T2-weighted imaging and DWI (Az = 0.900) was significantly greater than that of T2-weighted imaging alone (Az = 0.828) (p < 0.001). The mean tumor ADC values were significantly lower in patients with ECE than patients without ECE (p < 0.001)., Conclusion: DWI at 3 T in addition to T2-weighted imaging improves the ability to predict ECE in patients with prostate cancer. Furthermore, tumor ADC values in patients with and without ECE are significantly different.

Objective: The objective of our study was to evaluate the value of the apparent diffusion coefficient (ADC) from diffusion-weighted imaging (DWI) as a predictor of extracapsular extension (ECE) in patients with localized prostate cancer., Materials and Methods: Enrolled in this study were 167 patients who underwent preoperative DWI at 3 T followed by surgery. Univariate and multivariate analyses including clinical variables (serum prostate-specific antigen level, biopsy-based Gleason score, clinical stage, greatest percentage of cancer in all biopsy cores, and presence of perineural invasion) and tumor ADC data were performed for predicting ECE. Receiver operating characteristic curve analysis was also performed to investigate the diagnostic performance of the clinical variables and tumor ADC for predicting ECE., Results: Histopathologic results indicated that 23 (13.8%) patients had ECE. At univariate analysis, tumor ADC, biopsy-based Gleason score, the presence of perineural invasion, and greatest percentage of cancer in all biopsy cores were associated with ECE (p<0.05). Multivariate analysis revealed that the greatest percentage of cancer in all biopsy cores (p=0.001), biopsy-based Gleason score (p=0.015), and tumor ADC (p=0.032) were independent predictors of ECE. For predicting ECE, the area under the curve (AUC) of tumor ADC was 0.771, which is the second best AUC of all the variables evaluated., Conclusion: As an imaging biomarker, tumor ADC may have potential for predicting ECE before surgery in patients with prostate cancer. Further studies investigating this possibility are warranted.