Search

Prostate cancer (PCa) is common among men worldwide and is a major cause of morbidity and mortality. The detection of PCa has historically followed a stepwise process of prostate-specific antigen screening followed with systematic transrectal ultrasound-guided biopsy. Magnetic resonance imaging (MRI), utilizing a set of sequences to assess morphology and function, has gained clinical acceptance to detect, characterize, and stage PCa. The Prostate Imaging - Reporting and Data System has helped facilitate the standardization of reporting across institutions and increased adoption of this method. In this review, we will (1) discuss the strengths and weaknesses of conventional diagnostic methods; (2) describe the clinical utility of prostate MRI, specifically addressing its uses in the detection and staging of PCa; and (3) list important technical parameters required for state-of-the-art prostate MRI.

Purpose: Prostatic urethral lift with UroLift is a minimally invasive approach to treat symptomatic benign prostatic hypertrophy. This device causes artifacts on prostate magnetic resonance images. Our aim was to evaluate the impact of artifact on prostate magnetic resonance image quality. Materials and Methods: This was a single-center retrospective review of patients with UroLift who subsequently had prostate magnetic resonance imaging. Two readers graded UroLift artifact on each pulse sequence using a 5-point scale (1dnondiagnostic; 5dno artifact). Prostate Imaging Quality scores were assigned for the whole data set. The volume of gland obscured by artifact was measured. Linear and logistic regression models were used to identify predictors of poor image quality. Results: Thirty-seven patients were included. Poor image quality occurs more in the transition zone than the peripheral zone (15% vs 3%), at base/mid regions vs the apex (13%, 9%, and 5%, respectively) and on diffusion-weighted images vs T2-weighted and dynamic contrast-enhanced sequences (27%, 0.3%, 0%, respectively; P < .001). Suboptimal image quality (ie, Prostate Imaging Quality score ≤2) was found in 16%-24% of exams. The percentage of gland obscured by the UroLift artifact was higher on diffusion-weighted images and dynamic contrast-enhanced sequences than T2-weighted (32%, 9%, and 6%, respectively; P < .001). Conclusions: UroLift artifact negatively affects prostate magnetic resonance image quality with greater impact in the mid-basal transition zone, obscuring a third of the gland on diffusion-weighted images. Patients considering this procedure should be counseled on the impact of this device on image quality and its potential implications for any image-guided prostate cancer workup. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of enema and dietary restrictions on prostate MR image quality metrics and to assess inter-reader agreement for these metrics.Methods: This retrospective study included 195 men divided into groups based on their compliance with preparation instructions before prostate MRI (Enema + Diet, n = 98; Enema, n = 42; Diet, n = 35; Control [no compliance], n = 20). Four readers independently assessed six image quality metrics on a 5-point scale. Between-group comparisons were made using Wilcoxon rank sum test. Inter-reader agreement was calculated using Fleiss' kappa.Results: Compared with the Control group, image quality with respect to rectal stool/gas, distortion of diffusion-weighted images, overall image quality, and confidence in assessment was higher in the Enema + Diet, Enema, and Diet groups (p  < 0.05 for all comparisons). The Enema + Diet and Enema groups had significantly higher scores than the Diet group for rectal stool/gas (p < 0.001 and 0.005, respectively). The Enema + Diet and Diet groups had higher scores than the Control group for rectal peristalsis (p = 0.027 and 0.009, respectively), but there were no significant differences in motion artifacts on T2-weighted images. Agreement among readers was fair, with kappa values ranging from 0.25 to 0.37.Conclusion: Enema and dietary restriction can improve the quality of prostate MRI by decreasing rectal distension and distortion of diffusion-weighted images and by increasing reader confidence in image assessment. Inter-reader agreement using subjective criteria for analysis of MRI quality is fair. [ABSTRACT FROM AUTHOR]

Positron emission tomography (PET) using fluorodeoxyglucose (18F-FDG) combined with magnetic resonance imaging (MR) is an emerging hybrid modality that has shown utility in evaluating abdominal and pelvic disease entities. Together, the high soft tissue contrast and metabolic/functional imaging capabilities make this modality ideal for oncologic imaging in many organ systems. Its clinical utility continues to evolve and future research will help solidify its role in oncologic imaging. In this manuscript, we aim to (1) provide an overview of the various PET/MR systems, describing the strengths and weaknesses of each system, and (2) review the oncologic applications for 18F-FDG PET/MR in the abdomen and pelvis. [ABSTRACT FROM AUTHOR]

Hepatic capsular retraction is a morphologic descriptor that refers to invagination or focal flattening of the typical smooth contour of the liver capsule. It is an uncommon finding that, when combined with other imaging features and clinical context, can help to refine the differential diagnosis in patients with liver lesions. Although this descriptor has historically been used in reference to a small subset of benign and malignant lesions, the differential has since been expanded with the discovery of new entities causing capsular retraction as well as with novel and increased use of liver-directed treatment techniques. Additionally, modern imaging techniques now allow for improved detection and characterization of capsular retraction. In this review, we discuss these common and uncommon causes of capsular retraction, with an emphasis on findings from body MRI. [ABSTRACT FROM AUTHOR]

Management of incidental renal masses is in evolution. Recognition that cystic renal tumors generally act in an indolent fashion has led to less aggressive intervention. The ability of radiologists to stratify risk of malignancy, and in some cases, specify a precise diagnosis, is paramount to patient management. We review pathologies that present as cystic renal masses and how to best stratify malignancy risk. [ABSTRACT FROM AUTHOR]

Objective: To analyze the full spectrum of patients presenting with radiologically-identified infiltrative renal masses (IRMs), including those managed surgically or otherwise, with focus on clinical presentation/prognosis.Methods: All 280 patients presenting with radiologically-identified renal mass with infiltrative features (2008-2017) were retrospectively reviewed. Poorly-defined interface between tumor and parenchyma and irregular shape (nonelliptical) in one or more distinct/unequivocal areas were required for classification as IRM. IRM was confirmed in 265 and clinical characteristics and outcomes were assessed.Results: Median age/tumor size were 65-years/6.9 cm, respectively, and 225 patients (85%) were R.E.N.A.L. = 10-12. Overall, 181 patients (68%) presented symptomatically, locally-advanced cancer (cT3-T4) was observed in 176 (66%) and disseminated disease and/or lymphadenopathy (>2 cm) in 181(68%). Clinical/radiographic findings were suggestive of etiology and could direct evaluation, but were nonspecific for definitive diagnosis. Renal-mass biopsy was performed in 103 patients and diagnostic in 97 (94%). Renal surgery was only performed in 82 patients (31%) and partial nephrectomy in 3 (1.1%). Overall, 72 patients (27%) received systemic chemotherapy and 59 (22%) targeted therapy. Final-diagnosis was renal cell carcinoma in 94 patients (35%), including 49 with highly-aggressive histology (sarcomatoid/rhabdoid/collecting-duct/medullary/unclassified). High-grade urothelial-carcinoma was found in 70 (26%), and lymphoma/metastatic cancer in 26 (10%)/25 (9%), respectively. Overall, 153 patients (58%) died; 138 (52%) cancer-related at median of 5 months. The majority of patients with renal cell carcinoma, urothelial-carcinoma, and renal metastasis died, almost exclusively cancer-related, at medians of 8, 3, and 2 months, respectively.Conclusion: Our series includes the full spectrum of IRMs and confirms predominance of symptomatic, poorly-differentiated, highly-lethal malignancies. Our study highlights the overriding importance of identifying infiltrative features, a simple radiologic diagnosis, during assessment of renal masses. [ABSTRACT FROM AUTHOR]

Purpose: The goal of this study was to determine the predictive value of prostate-specific antigen density (PSAD) plus Prostate Imaging Reporting and Data System (PI-RADS) category for the detection of clinically significant prostate cancer.Materials and Methods: This retrospective study included 526 men without known prostate cancer (initial diagnosis group) and 133 men with prostate cancer grade group 1 (active surveillance group) who underwent magnetic resonance imaging-guided and/or systematic prostate biopsy procedures between August 2014 and October 2018. Prostate specific antigen (PSA), PSAD, and PI-RADS category were entered into logistic regression models for predicting clinically significant prostate cancer (grade group ≥2) at biopsy. Receiver operating characteristic curve analysis was performed to assess model accuracy.Results: The area under the curve (AUC) increased when PSAD was combined with PI-RADS in the initial diagnosis group (difference in AUC = 0.031; 95% confidence interval: 0.012, 0.050; P = 0.002) but not in the active surveillance group (difference in AUC = 0.016; 95% confidence interval: -0.040, 0.071; P = 0.579). When a PSAD threshold of 0.15 was applied, the frequency of clinically significant prostate cancer in patients with a PI-RADS score of 3 or lower decreased from 9.8% to 5.6% in the initial diagnosis group and from 10.7% to 2.7% in the active surveillance group.Conclusions: The addition of PSAD improves the predictive performance of PI-RADS in men without known prostate cancer. A PSAD threshold of 0.15 can help to minimize the number of missed clinically significant prostate cancer cases in men with a PI-RADS score of 3 or lower who decide to defer biopsy. [ABSTRACT FROM AUTHOR]