Utility of Prostate Health Index Density for Biopsy Strategy in Biopsy-Naïve Patients With PI-RADS v2.1 Category 3 Lesions.

BACKGROUND: Category 3 lesions in PI-RADSv2.1 pose diagnostic challenges, complicating biopsy decisions. Recent biomarkers like prostate health index (PHI) have shown higher specificity in detecting clinically significant prostate cancer (csPCa) than prostate-specific antigen (PSA). Yet their integration with MRI remains understudied. PURPOSE: To evaluate the utility of PSA and PHI with its derivatives for detecting csPCa in biopsy-naïve patients with category 3 lesion on initial prostate MRI scan. STUDY TYPE: Retrospective. POPULATION: One hundred ninety-three biopsy-naïve patients who underwent MRI, PSA, and PHI testing, followed by both targeted and systematic biopsies. FIELD STRENGTH/SEQUENCE: Turbo spin-echo T2-weighted imaging, diffusion-weighted single-shot echo-planar imaging, and dynamic contrast-enhanced T1-weighted fast field echo sequence imaging in 3 T. ASSESSMENT: PHI density (PHID) and PSA density (PSAD) derived by dividing serum PHI and PSA with prostate volume (MRI based methodology suggested by PI-RADSv2.1). Risk-stratified models to evaluate the utility of markers in triaging patients for biopsy, including low-, intermediate-, and high-risk groups. STATISTICAL TESTS: Independent t-test, Mann-Whitney U test, Mantel-Haenszel test, generalized estimating equation, and receiver operating characteristic (ROC) curve analysis were used. Statistical significance defined as P < 0.05. RESULTS: CsPCa was found in 16.6% (32/193) of patients. PHID had the highest area under the ROC curve (AUROC) of 0.793, followed by PHI of 0.752, PSAD of 0.750, and PSA of 0.654. PHID with two cut-off points (0.88/mL and 1.82/mL) showed the highest potential biopsy avoidance of 47.7% (92/193) with 5% missing csPCa, and the lowest intermediate-risk group (borderline decision group) at 38.9% (75/193), compared to PSA and PHI. DATA CONCLUSION: PHID demonstrated better potential in triaging patients with category 3 lesions, possibly aiding more selective and confident biopsy decisions for csPCa detection, than traditional markers. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY: Stage 5.

Inter-method agreement between wash-in and wash-out computed tomography for characterizing hyperattenuating adrenal lesions as adenomas or non-adenomas.

OBJECTIVES: To investigate inter-method agreement between wash-out and wash-in computed tomography (CT) to determine whether hyperattenuating adrenal lesions are characterized as adenomas or non-adenomas. METHODS: We evaluated 243 patients who underwent wash-out CT for a solid enhancing hyperattenuating (i.e., > 10 Hounsfield unit [HU]) adrenal mass of ≥ 1 to < 4 cm. Wash-out (absolute percentage wash-out [APW]; relative percentage wash-out [RPW]) and wash-in values (enhancement ratio [ER]; relative enhancement ratio [RER]) were analyzed by two independent readers. Diagnostic criteria of wash-out CT for adenoma were APW ≥ 60% or RPW ≥ 40% (conventional method). Three different criteria for wash-in CT were set: ER ≥ 3.0; RER ≥ 200%; and RER ≥ 210%. Concordance rate and inter-method agreement between wash-out and wash-in CT were investigated using Gwet's AC1. RESULTS: For all lesions, concordance rates between wash-out and wash-in CT were > 83%. AC1 between conventional method and ER ≥ 3.0 or between conventional method and RER ≥ 200% were identically 0.843 for reader 1 and 0.776 for reader 2. AC1 between conventional method and RER ≥ 210% were 0.780 for reader 1 and 0.737 for reader 2. For lesions of > 10 to ≤ 30 HU, concordance rates between wash-out and wash-in CT were > 89%. AC1 between conventional method and ER ≥ 3.0 or between conventional method and RER ≥ 200% were identically 0.914 for reader 1 and 0.866 for reader 2. AC1 between conventional method and RER ≥ 210% were 0.888 for reader 1 and 0.874 for reader 2. CONCLUSION: In approximately 90% of patients with a hyperattenuating adrenal lesion of ≥ 1 to < 4 cm and >10 to ≤ 30 HU, wash-out CT with 15-min contrast-enhanced images may be replaced by wash-in CT. KEY POINTS: • An enhancement ratio of ≥ 3.0 or a relative enhancement ratio of ≥ 200% appears to be appropriate as the threshold of wash-in computed tomography (CT) comprising unenhanced and 1-min contrast-enhanced CT. • Measurement of enhancement ratio or relative enhancement ratio was reproducible. • We found good agreement between wash-in and wash-out CT for determining whether hyperattenuating adrenal lesions of ≥ 1 to < 4 cm and >10 to ≤ 30 Hounsfield unit would be characterized as adenomas.

Prostate MRI Qualification: AJR Expert Panel Narrative Review.

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.

Lumbosacral plexopathy caused by the perineural spread of pelvic malignancies: clinical aspects and imaging patterns.

BACKGROUND: Perineural spread (PNS) of tumors from pelvic malignancies is a rare phenomenon but constitutes an important differential diagnosis of lumbosacral plexopathy (LSP). Herein, we describe the clinical and imaging features of patients with LSP due to PNS of pelvic malignancies along with a literature review. METHODS: We retrospectively reviewed 9 cases of LSP caused by PNS of pelvic malignancy between January 2006 and August 2021, and all clinical and imaging parameters were recorded in detail. Clinical symptoms and signs of patients were described and listed in the order in which they occurred. The results of imaging test were analyzed to describe specific findings in LSP caused by PNS. RESULTS: This study enrolled nine adult patients (mean age, 50.1 years). Two cases initially presented as LSP and were later diagnosed with pelvic malignancy. Pain in the perianal or inguinal area preceded pain at the extremities in six patients. Neurogenic bladder or bowel symptoms developed in five patients. On the magnetic resonance imaging (MRI), the S1-S2 spinal nerve was most commonly involved, and S1 myotome weakness was more prominent in six patients than the other myotomes. One patient had an intradural extension. 18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) and computed tomography (CT) showed abnormal signal intensity in six patients. No abnormality in 18F-FDG PET/CT was detected in the nervous structures in one patient. Only four patients survived until the last follow-up visit. CONCLUSIONS: Though rare, physicians should always keep in mind the possibility of LSP due to the PNS in patients with pelvic malignancy. Thorough physical examination and history taking could provide clues for diagnosis. Pelvic MRI and 18F-FDG-PET/CT should be considered for patients with LSP to rule out neoplastic LSP.

Yield of concurrent systemic biopsy during MRI-targeted biopsy according to Prostate Imaging Reporting and Data System version 2 in patients with suspected prostate cancer.

OBJECTIVES: To investigate the yield of concurrent systemic biopsy (SB) during MRI-targeted biopsy (MRTB) as Prostate Imaging Reporting and Data System (PI-RADS) version 2 (v2) interpretations in patients with suspected prostate cancer (PCa). METHODS: A total of 285 patients with suspected PCa underwent prebiopsy 3-T MRI, followed by MRI-transrectal ultrasound fusion targeted biopsy and concurrent standard SB for lesions with PI-RADS v2 scores 3-5. Detection rates and positive core rates of PCa and clinically significant cancer (CSC) were evaluated. RESULTS: In concurrent MRTB and SB, PCa and CSC detection rates were 18.9% and 9.4% for PI-RADS score 3, 45.9% and 32.4% for PI-RADS score 4, and 82.1% and 72.6% for PI-RADS score 5, respectively. Overall detection rate of CSCs (40.0%) for concurrent MRTB and SB was significantly higher than that of MRTB (34.4%, p = 0.004) or SB alone (27.7%, p < 0.001): an increase of 5.6% (16 patients) compared with MRTB alone. For patients with PI-RADS score 4 or 5, the CSC detection rate of concurrent MRTB and SB was 47.0%, an increase of 6.1% when compared with MRTB (40.9%) only (p < 0.001). Of the 110 patients with both MRTB- and SB-positive findings, 22 (20.0%) had the highest Gleason score in SB compared with that in MRTB. In 9.5% (27/285) patients including 12 patients with CSCs, only SB was positive, with negative MRTB. CONCLUSION: Concurrent SB with MRTB based on PI-RADS v2 can yield a higher CSC detection rate compared with MRTB alone in patients with suspected PCa. KEY POINTS: • Concurrent SB with MRTB yields an increase of 5.6% CSC detection compared with MRTB alone. • Of both MRTB- and SB-positive findings, 20.0% patients have upgraded Gleason score in SB. • In 18.4% patients, only SB was positive, with negative MRTB. Adding MRTB to SB is helpful for adequate risk stratification, reducing diagnostic uncertainty of PCa.

MRI Targeted Prostate Biopsy Techniques: AJR Expert Panel Narrative Review.

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: A Critical Review, From the AJR Special Series on Radiology Reporting and Data Systems.

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).

Variability of the Positive Predictive Value of PI-RADS for Prostate MRI across 26 Centers: Experience of the Society of Abdominal Radiology Prostate Cancer Disease-focused Panel.

Background Prostate MRI is used widely in clinical care for guiding tissue sampling, active surveillance, and staging. The Prostate Imaging Reporting and Data System (PI-RADS) helps provide a standardized probabilistic approach for identifying clinically significant prostate cancer. Despite widespread use, the variability in performance of prostate MRI across practices remains unknown. Purpose To estimate the positive predictive value (PPV) of PI-RADS for the detection of high-grade prostate cancer across imaging centers. Materials and Methods This retrospective cross-sectional study was compliant with the HIPAA. Twenty-six centers with members in the Society of Abdominal Radiology Prostate Cancer Disease-focused Panel submitted data from men with suspected or biopsy-proven untreated prostate cancer. MRI scans were obtained between January 2015 and April 2018. This was followed with targeted biopsy. Only men with at least one MRI lesion assigned a PI-RADS score of 2-5 were included. Outcome was prostate cancer with Gleason score (GS) greater than or equal to 3+4 (International Society of Urological Pathology grade group ≥2). A mixed-model logistic regression with institution and individuals as random effects was used to estimate overall PPVs. The variability of observed PPV of PI-RADS across imaging centers was described by using the median and interquartile range. Results The authors evaluated 3449 men (mean age, 65 years ± 8 [standard deviation]) with 5082 lesions. Biopsy results showed 1698 cancers with GS greater than or equal to 3+4 (International Society of Urological Pathology grade group ≥2) in 2082 men. Across all centers, the estimated PPV was 35% (95% confidence interval [CI]: 27%, 43%) for a PI-RADS score greater than or equal to 3 and 49% (95% CI: 40%, 58%) for a PI-RADS score greater than or equal to 4. The interquartile ranges of PPV at these same PI-RADS score thresholds were 27%-44% and 27%-48%, respectively. Conclusion The positive predictive value of the Prostate Imaging and Reporting Data System was low and varied widely across centers. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Milot in this issue.

Utility of diffusion-weighted imaging in association with pathologic upgrading in biopsy-proven grade I endometrial cancer.

BACKGROUND: Prediction of pathologic upgrading is clinically meaningful to identify the optimal candidate of fertility-preserving hormonal treatment in the young patients with biopsy-proven grade I endometrial cancer. PURPOSE: To investigate the utility of diffusion-weighted imaging (DWI) in association with pathologic upgrading in endometrial cancer. STUDY TYPE: Retrospective. SUBJECTS: Preoperative MRI datasets of 221 patients with grade I endometrial cancer on endometrial biopsy (n = 146), dilatation and curettage (n = 66), or either (n = 9). FIELD STRENGTH/SEQUENCE: 3.0T, including T2 -weighted imaging, DWI with a b-value of 1000 s/mm2 , and dynamic contrast enhanced imaging. ASSESSMENT: The tumor size was determined as the longest diameter of the lesion. The minimum apparent diffusion coefficient (ADCmin ) was calculated using histogram analysis of the entire tumor. STATISTICAL TESTS: Mann-Whitney U-test, Pearson's chi-square test, Fisher's exact test, intraclass correlation coefficient (ICC) analysis, receiver operating characteristic (ROC) curve analysis, univariate and multivariate logistic regression analysis. RESULTS: Pathologic upgrading was identified in 42 patients (19.0%). Patients with pathologic upgrading had larger tumors and showed lower ADCmin values than those without pathologic upgrading (both P < 0.001). The area under the ROC curve of ADCmin and tumor size was 0.812 and 0.758, respectively. On multivariate analysis, tumor ADCmin ≤0.600 × 10-3 mm2 /s (odds ratio [OR], 11.8; P < 0.001) and tumor size on MRI >3 cm (OR, 3.24; P = 0.009) were independently associated with pathologic upgrading. Upgrading occurred in 23 of 31 patients (74.2%) with ADCmin ≤0.600 × 10-3 mm2 /s and tumor size >3 cm, and in 7 of 114 patients (6.1%) with ADCmin >0.600 × 10-3 mm2 /s and tumor size ≤3 cm. DATA CONCLUSION: Tumor ADC and tumor size on MRI may be useful parameters in association with pathologic upgrading in biopsy-proven grade I endometrial cancer. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:117-123.

Histogram analysis of apparent diffusion coefficients for predicting pelvic lymph node metastasis in patients with uterine cervical cancer.

OBJECTIVE: To investigate the value of apparent diffusion coefficient (ADC) histogram analysis in predicting pelvic lymph node (LN) metastasis in patients with cervical cancer undergoing surgery. MATERIALS AND METHODS: A total of 162 cervical cancer patients who underwent radical abdominal hysterectomy with pelvic LN dissection performed with pelvic 3 T-MRI including diffusion-weighted imaging were enrolled in this study. The ADC histogram variables (minimum, mean, median, 97.5th percentile [ADC97.5], and maximum) of the tumors were developed using in-house software. For predicting pelvic LN metastasis, clinical and imaging variables were evaluated using logistic regression and receiver-operating characteristic (ROC) analyses. RESULTS: Pelvic LN metastasis was identified histopathologically in 50 patients (30.9%). In patients with LN metastasis, all ADC histogram variables were significantly different from those without LN metastasis (all p < 0.01). Univariate analysis demonstrated that long- and short-axis diameter of LN, MRI T-stage, squamous cell carcinoma antigen, tumor size, and the ADC97.5 were significantly associated with pelvic LN metastasis (all p < 0.05). However, multivariate analysis demonstrated that the ADC97.5 was the only independent predictor of pelvic LN metastasis (odds ratio, 0.996; p = 0.001). The area under the ROC curve of ADC97.5 was 0.782, which was the greatest among all variables. Interobserver agreement of all ADC histogram variables was fair to good. DISCUSSION: The ADC97.5 from histogram analysis may be a useful marker for the prediction of pelvic LN metastasis in patients with cervical cancer.

Value of blood oxygenation level-dependent MRI for predicting clinical outcomes in uterine cervical cancer treated with concurrent chemoradiotherapy.

OBJECTIVES: To investigate the value of blood oxygenation level-dependent (BOLD) MRI as a predictor of clinical outcomes in cervical cancer patients treated with concurrent chemoradiotherapy (CCRT). METHOD: Enrolled 92 patients with stage IB2-IVB cervical cancer who received CCRT underwent 3-T BOLD MRI before treatment. The R2* value (rate of spin dephasing, s-1) was measured in the tumor. Cox regression analysis was used to evaluate the associations of imaging and clinical parameters with progression-free survival (PFS) and cancer-specific survival (CSS). Inter-reader reliability for the R2* measurements was evaluated using an intraclass correlation coefficient (ICC). RESULTS: Tumor R2* values were significantly different between patients with and without disease progression (p < 0.001). Multivariate analysis demonstrated that tumor R2* value was significantly independent factor for PFS (hazard ratio [HR] = 5.746, p < 0.001) and CSS (HR = 12.878, p = 0.001). Additionally, squamous cell carcinoma antigen (HR = 1.027, p = 0.001) was significantly independent factor for PFS. Inter-reader reliability for the R2* measurements was good (ICC = 0.702). CONCLUSION: Pretreatment 3-T BOLD MRI may be useful for predicting clinical outcomes in uterine cervical cancer patients treated with CCRT, with good inter-reader reliability. KEY POINTS: • Tumor R2* values are different between patients with and without disease progression. • The R2* value is an independent factor for treatment outcomes in cervical cancer. • Inter-reader reliability for R2* measurements using BOLD MRI is good.

Prognostic value of ADC quantification for clinical outcome in uterine cervical cancer treated with concurrent chemoradiotherapy.

OBJECTIVES: To investigate the prognostic value of diffusion-weighted imaging (DWI) in predicting clinical outcome in patients with cervical cancer after concurrent chemoradiotherapy (CCRT). METHODS: We enrolled 124 cervical cancer patients who received definitive CCRT and underwent 3 T-MRI before and 1 month after initiating treatment. The mean apparent diffusion coefficient (ADC) value was measured on the tumor and the changes in ADC percentage (ΔADCmean) between the two time points were calculated. The Cox proportion hazard model was used to evaluate the associations between imaging or clinical variables and progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS). RESULTS: In multivariate analysis, ΔADCmean was the only independent predictor of PFS (hazard ratio [HR] = 0.2379, p = 0.005), CSS (HR = 0.310, p = 0.024), and OS (HR = 0.217, p = 0.002). Squamous cell carcinoma antigen, histology, and pretreatment tumor size were significantly independent predictors of PFS. Tumor size response was significantly independent predictor of CSS and OS. Using the cutoff values of ΔADCmean, the PFS was significantly lower for ΔADCmean < 27.8% (p = 0.001). The CSS and OS were significantly lower for ΔADCmean < 16.1% (p = 0.002 and p < 0.001, respectively). CONCLUSION: The percentage change in tumor ADC may be a useful predictor of disease progression and survival in patients with cervical cancer treated with CCRT. KEY POINTS: • DWI is widely used as a potential marker of tumor viability. • Percentage change in tumor ADC (ΔADC mean ) was an independent marker of PFS, CSS, and OS. • Survival was better in patients with ≥ ΔADC mean cutoff value than with < the cutoff value.

Prebiopsy Biparametric MRI for Clinically Significant Prostate Cancer Detection With PI-RADS Version 2: A Multicenter Study.

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.

Clinically insignificant prostate cancer suitable for active surveillance according to Prostate Cancer Research International: Active surveillance criteria: Utility of PI-RADS v2.

BACKGROUND: Active surveillance (AS) is an important treatment strategy for prostate cancer (PCa). Prostate Imaging-Reporting and Data System (PI-RADS) v2 has been addressed, but few studies have reported the value of PI-RADS v2 for assessing risk stratification in patients with PCa, especially on selecting potential candidates for AS. PURPOSE: To investigate the utility of PI-RADS v2 and apparent diffusion coefficient (ADC) in evaluating patients with insignificant PCa, who are suitable for AS. STUDY TYPE: Retrospective. SUBJECTS: In all, 238 patients with PCa who met the Prostate Cancer Research International: Active Surveillance criteria underwent radical prostatectomy. FIELD STRENGTH/SEQUENCE: 3.0T, including T2 -weighted, diffusion-weighted, and dynamic contrast-enhanced imaging. ASSESSMENT: Insignificant cancer was defined histopathologically as an organ-confined disease with a tumor volume <0.5 cm3 without Gleason score 4-5. Patients were divided into two groups based on the PI-RADS v2 and tumor ADC: A, PI-RADS score ≤3 and ADC ≥1.095 × 10-3 mm2 /s; and B, PI-RADS score 4-5 or ADC <1.095 × 10-3 mm2 /s. Preoperative clinical and imaging variables were evaluated regarding the associations with insignificant cancer. RESULTS: Of the 238 patients, 101 (42.8%) were diagnosed with insignificant cancer on pathological findings. The number of positive cores, prostate-specific antigen density (PSAD), PI-RADS v2 and tumor ADC were significantly associated with insignificant cancer on univariate analysis (P < 0.05). However, multivariate analysis indicated tumor ADC (odds ratio [OR] = 4.57, P < 0.001) and PI-RADS v2 (OR = 3.60, P < 0.001) were independent predictors of insignificant cancer. Area under the receiver operating characteristics curve (AUC) reached 0.803 when PI-RADS v2 (AUC = 0.747) was combined with tumor ADC (AUC = 0.786). DATA CONCLUSION: The PI-RADS v2 together with tumor ADC may be a useful marker for predicting patients with insignificant PCa when considering AS. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1072-1079.

Prebiopsy Multiparametric MRI With Cancer-Negative Findings in Men With Suspected Prostate Cancer: Evaluation Using Prostate Imaging Reporting and Data System Version 2.

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.

Postoperative Outcome of Cystic Renal Cell Carcinoma Defined on Preoperative Imaging: A Retrospective Study.

PURPOSE: We evaluated the postoperative outcome of cystic renal cell carcinoma defined on preoperative computerized tomography. We also sought to find the optimal cutoff of the cystic proportion in association with patient prognosis. MATERIAL AND METHODS: In this institutional review board approved study with waiver of informed consent, 1,315 patients were enrolled who underwent surgery for a single renal cell carcinoma with preoperative computerized tomography. The cystic proportion of renal cell carcinoma was determined on computerized tomography. The optimal cutoff of the cystic proportion was explored regarding cancer specific survival. Renal cell carcinomas were categorized as cystic or noncystic renal cell carcinoma according to a conventional cutoff (ie cystic proportion 75% or greater) and an optimal cutoff. Postoperative outcomes were then compared between the 2 groups. Multivariate Cox regression analysis was performed to determine the independent predictor of cancer specific survival. RESULTS: Of the 1,315 lesions 107 (8.1%) were identified as cystic renal cell carcinoma according to a conventional cutoff. The postoperative outcome of cystic renal cell carcinoma was significantly better than that of noncystic renal cell carcinoma (p <0.001). Neither metastasis nor recurrence developed after surgery in patients with cystic renal cell carcinoma. In association with the cancer specific survival rate, the optimal cutoff of the cystic proportion was 45% and 197 cases (15.0%) were accordingly defined as cystic renal cell carcinoma. On Cox regression analysis, a cystic proportion of 45% or greater of the renal cell carcinoma was an independent predictor of a favorable outcome regarding cancer specific survival (HR 0.34, p = 0.03). CONCLUSIONS: Cystic renal cell carcinoma defined on preoperative computerized tomography is associated with low metastatic potential and favorable outcomes after surgery. Particularly, a cystic proportion of 45% or greater is an independent prognostic factor for favorable survival.

Evaluation of extracapsular extension in prostate cancer using qualitative and quantitative multiparametric MRI.

PURPOSE: To investigate the value of multiparametric magnetic resonance imaging (mpMRI) for extracapsular extension (ECE) in prostate cancer (PCa). MATERIALS AND METHODS: In all, 292 patients who received radical prostatectomy and underwent preoperative mpMRI at 3T were enrolled retrospectively. For determining the associations with ECE, the likelihood of ECE was assessed qualitatively on T2 -weighted imaging (T2 WI) and combined T2 WI and diffusion-weighted imaging (DWI) or dynamic contrast-enhanced imaging (DCEI). Quantitative MRI parameters were measured in PCa based on histopathological findings. Two models for detecting ECE including imaging and clinical parameters were developed using multivariate analysis: Model 1 excluding combined T2 WI and DWI and DCEI and Model 2 excluding combined T2 WI and DWI, and combined T2 WI and DCEI. Diagnostic performance of imaging parameters and models was evaluated using the area under the receiver operating characteristics curve (Az). RESULTS: For detecting ECE, the specificity, accuracy, and Az of combined T2 WI and DWI or DCEI were statistically better than those of T2 WI (P < 0.05), and all quantitative MRI parameters showed a statistical difference between the patients with and without ECE (P < 0.05). On multivariate analysis, significant independent markers in Model 1 were combined T2 WI and DWI, combined T2 WI and DCEI, and Ktrans (P < 0.05). In Model 2, significant markers were combined T2 WI and DWI and DCEI, Ktrans , Kep , and Ve (P < 0.05). The Az values of models 1 and 2 were 0.944 and 0.957, respectively. CONCLUSION: mpMRI may be useful to improve diagnostic accuracy of the models for determining the associations with ECE in PCa. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;45:1760-1770.

Accuracy of preoperative multiparametric magnetic resonance imaging for prediction of unfavorable pathology in patients with localized prostate cancer undergoing radical prostatectomy.

INTRODUCTION: We investigated the accuracy of multiparametric MRI (mpMRI) for preoperative staging and its influence on the determination of neurovascular bundle sparing and disease prognosis in patients with localized prostate cancer. METHODS: We reviewed 1045 patients who underwent radical prostatectomy with preoperative mpMRI at a single institution. Clinical local stages determined from mpMRI were correlated with preoperative and postoperative pathological outcomes. RESULTS: The sensitivity and specificity to diagnose seminal vesicle invasion (SVI) on mpMRI were 43.8 and 95.4 %, respectively. The negative predictive value was 78.9 %. The sensitivity and specificity to diagnose extracapsular extension (ECE) were 54.5 and 80.5 %, respectively. The overall sensitivity and specificity of diagnosing pathological T3 or higher were 52.6 and 82.1 %, respectively. Non-organ-confined disease determined by mpMRI was significantly associated with positive surgical margin and pathological T3 disease on multivariate analysis. Preoperative adverse findings on mpMRI were significantly associated with performance of the non-nerve-sparing technique. CONCLUSION: mpMRI did not show outstanding diagnostic accuracy relative to our expectations in predicting SVI or ECE preoperatively. However, adverse findings on preoperative mpMRI were significantly related to worse postoperative pathological outcomes as well as postoperative biochemical recurrence.

Small (< 4 cm) Renal Tumors With Predominantly Low Signal Intensity on T2-Weighted Images: Differentiation of Minimal-Fat Angiomyolipoma From Renal Cell Carcinoma.

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 mm2/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.