Imaging abnormalities of the pancreas in diabetes: implications for diagnosis and treatment.

PURPOSE OF REVIEW: Radiographic imaging of the pancreas has drawn recent interest as pancreas volume may serve as a biomarker in identifying the likelihood of diabetes development, subtyping diabetes, and identifying prognostic indicators of poor ultimate outcomes. In this review, the role of pancreas imaging is discussed in various forms of diabetes including type 1 diabetes (T1D), type 2 diabetes (T2D), and diabetes of the exocrine pancreas, particularly diabetes following acute or chronic pancreatitis. RECENT FINDINGS: Recent literature of quantitative pancreatic imaging correlating with various forms of diabetes was reviewed. Imaging-derived pancreas volumes are lower in individuals with diabetes, in particular those with T1D. Additionally, morphologic changes, enhancement characteristics, fat content, and MRI signal changes have been observed in different diabetes subtypes. These characteristics, as well as potential confounding variables, are reviewed. Additionally, future areas of research in MRI, CT radiomics, and pancreatitis-related imaging predictors of diabetes are discussed. SUMMARY: Increased understanding of pancreas imaging features which predict diabetes and gauge prognosis has the potential to identify at-risk individuals and will become increasingly important in diabetes care. This article reviews the current knowledge of common pancreas imaging features as well as future directions of ongoing research in diabetes imaging.

Diagnosing Prostate Cancer: The Role of Intravesical Prostatic Gland Protrusion on Accuracy of Prostate Biopsies.

PURPOSE: We evaluated the association between intravesical prostate protrusion (IPP) and the detection rate of clinically significant prostate cancer (csPCa) on magnetic resonance imaging (MRI)-transrectal ultrasound (TRUS) fusion targeted biopsy (TB). MATERIALS AND METHODS: A total of 538 consecutive men who underwent MRI-TRUS fusion TB and concomitant systematic biopsy were evaluated. IPP on MRI was independently measured by 4 blinded reviewers. The primary outcome was per-lesion detection of csPCa on TB. We assessed the association between IPP and csPCa detection on TB, controlling for age, prostate specific antigen, Prostate Imaging Reporting and Data System® (PI-RADS®) score, prostate volume, targeted cores sampled and previous biopsy experience. RESULTS: A total of 847 PI-RADS 3 or greater lesions were targeted across 570 biopsies. Intra- and interrater reliability for measuring IPP was strong. A total of 81 (14.2%), 127 (22.3%), 237 (41.6%) and 125 (21.9%) men had 0, small, medium and large IPP, respectively. A total of 230, 392 and 196 lesions were PI-RADS 3, 4 and 5, respectively. Of the lesions 198 (34.7%) had csPCa on TB. The overall relationship between IPP size and csPCa found on TB was not significant; however, large IPP is associated with a significantly lower rate of csPCa detection than 0 IPP (p=0.007). Every mm increase in IPP is associated with a 5.6% decrease in the odds of csPCa detection on TB (p=0.004) and a 66.5% decrease in odds of detection in large IPP compared to 0 IPP (p=0.003). CONCLUSIONS: As the size of the IPP and volume increase, there is a decrease in the detection rate of csPCa on MRI-guided TB. These findings may be driven by poor MRI-TRUS co-registration and prostate asymmetry.

Impact of 18-French Rectal Tube Placement on Image Quality of Multiparametric Prostate MRI.

This study compared prostate multiparametric MRI (mpMRI) performed using an 18-French rectal tube in place throughout the examination after initial placement by a technologist (n = 97) with mpMRI performed without rectal tube placement (n = 99). Acquisition parameters were otherwise identical. Two radiologists scored subjective image quality and measured rectal diameter. For both readers, rectal tube placement was associated (p < .001) with improved ADC map quality, decreased DWI distortion, decreased rectal gas, and decreased rectal diameter. Findings support routine rectal tube placement for prostate mpMRI.

Atypical Hepatic Steatosis Patterns on MRI After Total Pancreatectomy With Islet Autotransplant.

OBJECTIVE. The purpose of this retrospective study was to investigate the prevalence and patterns of hepatic steatosis after total pancreatectomy with islet autotransplant (TPIAT) and to determine if the unique patterns of steatosis seen in this study correlated with islet graft function. MATERIALS AND METHODS. Fifty-two subjects who had undergone MRI after TPIAT were reviewed for the presence of hepatic steatosis. Patterns of steatosis were categorized into three groups: normal (no steatosis), homogeneous, and atypical. Demographics and outcomes were compared between the groups. Islet graft function 1 year after surgery was classified as full graft function, partial graft function, and graft failure. Statistical analysis was performed using ANOVA, Kruskal-Wallis, and Fisher exact tests. RESULTS. Sixty-three percent of patients had steatosis present on MRI after TPIAT (33 subjects of 52 total), and 48% (25/52) exhibited an atypical pattern. Twenty-four percent of the 37 patients who had MRI examinations before TPIAT showed steatosis preoperatively, yet none of these showed an atypical steatosis pattern. Islet graft function was not statistically different between the groups. The only statistically significant variable difference between the groups was body mass index (p = .02). CONCLUSION. Steatosis is a common finding after TPIAT, and atypical steatosis patterns frequently develop after the procedure, implying that the procedure itself is the causal factor. There was no correlation between islet graft function and the presence or pattern of steatosis. An atypical pattern of hepatic steatosis can therefore be considered an incidental finding after TPIAT and does not require additional workup or treatment.

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.

Minimally invasive microwave ablation provides excellent long-term outcomes for otherwise inaccessible hepatocellular cancer.

BACKGROUND AND OBJECTIVES: Thermal ablation can be used as a bridge to transplant or with curative intent for hepatocellular carcinoma (HCC). We report our experience with laparoscopic ablation of HCC in patients deemed inaccessible by the percutaneous approach. METHODS: We performed a retrospective review of surgical ablations from 2009 to 2017. Patient demographics, disease and treatment characteristics, and outcomes were abstracted from the medical record. Kaplan-Meier modeling was performed for survival and recurrence. RESULTS: Thirty-three patients were included with a median age of 62 (interquartile range [IQR], 57-67). Most patients were male (76%) and Caucasian (70%). Ninety-seven percent had underlying cirrhosis. Median model for end stage liver disease-sodium was 9.5 (IQR, 8-12). The median maximal diameter of ablated lesions was 2.6 cm (IQR, 1.8-3.0). Thirty-nine lesions were ablated; 97% were completed laparoscopically. The median maximal diameter of the ablation zone was 4.8 cm (IQR, 3.8-5.7) with a median difference of ablation zone to the tumor of 2.0 cm (IQR, 1.5-2.75). Twelve patients received additional treatment. Median disease-free survival was 66.7 months and median follow-up 42.9 months. Disease recurrence occurred in 13 patients (39%)-systemic recurrence in 6%, intrahepatic recurrence in 27% and local recurrence in 6%. CONCLUSION: Laparoscopic thermal ablation of HCC is safe and provides good oncologic outcomes for otherwise inaccessible tumors.

Spectrum of Early Postoperative Multidetector Computed Tomography Findings Following Cytoreductive Surgery With Hyperthermic Intraperitoneal Chemotherapy.

OBJECTIVE: To review and describe imaging findings on multidetector computed tomography in the early postoperative period after cytoreductive surgery with concomitant hyperthermic intraperitoneal chemotherapy (CRS + HIPEC). METHODS: This was a retrospective review of consecutive patients undergoing early (≤60 days) postoperative abdominopelvic multidetector computed tomography scans after CRS + HIPEC from 2014 to 2018 at a single institution. Two radiologists separately assessed bowel wall thickening, bowel wall enhancement, bowel dilation, ascites, and pleural effusion(s) and identified any other significant finding(s). RESULTS: Thirty-two patients met the inclusion criteria. The majority of patients demonstrated bowel wall thickening (53%; n = 17) and ascites (72%; n = 23), whereas postoperative ileus (35%; n = 10), pleural effusion(s) (24%; n = 7), and bowel wall hyperenhancement (6%; n = 1) were less common. Significant findings included anastomotic leak/perforation (13%; n = 4), fistula (13%; n = 4), abscess (13%; n = 4), and bladder leak (6%; n = 2). CONCLUSIONS: Multidetector computed tomography is an excellent imaging modality to identify common postoperative findings as well as complications following CRS + HIPEC.

A clinical prediction tool to determine the need for concurrent systematic sampling at the time of magnetic resonance imaging-guided biopsy.

OBJECTIVE: To develop a clinical prediction tool that characterises the risk of missing significant prostate cancer by omitting systematic biopsy in men undergoing transrectal ultrasonography/magnetic resonance imaging (TRUS/MRI)-fusion-guided biopsy. PATIENTS AND METHODS: A consecutive sample of men undergoing TRUS/MRI-fusion-guided biopsy with the UroNav® system (Invivo International, Best, The Netherlands) who also underwent concurrent systematic biopsy was included. By comparing the grade of cancer diagnosed on targeted and systematic biopsy cores, we identified cases where clinically significant disease (Gleason score ≥3+4) was only found on systematic and not targeted cores. Multivariable logistic regression analyses were used to identify predictive factors for finding significant cancer on systematic cores only. We then used these data to develop a nomogram and evaluated its utility using decision curve analysis. RESULTS: Of the 398 men undergoing TRUS/MRI-fusion-guided biopsy in our study, there were 46 (11.6%) cases in which clinically significant cancer was missed on targeted biopsy and detected on systematic biopsy. The clinical setting, number of MRI lesions identified, and the highest Prostate Imaging-Reporting and Data System (PI-RADS) score of the lesions, were all found to be predictors of this. Our model had a good discriminative ability (concordance index = 0.70). The results from our decision curve analysis show that this model provides a higher net clinical benefit than either biopsying all men or omitting biopsy in all patients when the threshold probability is <30%. CONCLUSION: We found that omitting concurrent systematic biopsy in men undergoing TRUS/MRI-fusion-guided biopsy would miss significant disease in more than one in 10 patients. We propose a prediction model with good discriminative ability that can be used to improve patient selection for performing concurrent systematic biopsy in order to minimise the number of missed significant cancers. It is important that our model is validated in external cohorts before being employed in routine clinical practice.

A Comparison of Radiologists' and Urologists' Opinions Regarding Prostate MRI Reporting: Results From a Survey of Specialty Societies.

OBJECTIVE: The purpose of this study is to compare radiologists' and urologists' opinions regarding prostate MRI reporting. SUBJECTS AND METHODS: Radiologist members of the Society of Abdominal Radiology and urologist members of the Society of Urologic Oncology received an electronic survey regarding prostate MRI reporting. RESULTS: The response rate was 12% (135/1155) for Society of Abdominal Radiology and 8% (54/663) for Society of Urologic Oncology members. Most respondents in both specialties prefer Prostate Imaging Reporting and Data System version 2 (PI-RADSv2) (radiologists, 84%; urologists, 84%), indicate that it is used at their institution (radiologists, 84%; urologists, 78%), understand its implications for patient care (radiologists, 89%; urologists, 71%), and agree that radiologists apply PI-RADSv2 categories correctly (radiologists, 57%; urologists, 61%). Both specialties agreed regarding major barriers to PI-RADSv2 adoption: radiologist inexperience using PI-RADSv2 (radiologists, 51%; urologists, 51%), urologist inexperience using PI-RADSv2 (radiologists, 46%; urologists, 51%), and lack of standardized templates (radiologists, 47%; urologists, 52%). The specialties disagreed (p ≤ 0.039) regarding whether reports should include the following management recommendations: targeted biopsy (radiologists, 58%; urologists, 34%), follow-up imaging (radiologists, 46%; urologists, 28%), and time interval for follow-up imaging (radiologists, 35%; urologists, 16%). There was also disagreement (p = 0.037) regarding report style: 54% of urologists preferred fully structured reports, whereas 53% of radiologists preferred hybrid structured and free-text reports. CONCLUSION: Radiologists and urologists both strongly prefer PI-RADSv2 for prostate MRI reporting, despite recognizing barriers to its adoption. Urologists more strongly preferred a fully structured report and disagreed with radiologists' preference to include management recommendations. Collaborative radiologist-urologist educational efforts are warranted to help optimize the effect of prostate MRI reporting in patient care.

Detection of Prostate Cancer: Quantitative Multiparametric MR Imaging Models Developed Using Registered Correlative Histopathology.

Purpose To develop multiparametric magnetic resonance (MR) imaging models to generate a quantitative, user-independent, voxel-wise composite biomarker score (CBS) for detection of prostate cancer by using coregistered correlative histopathologic results, and to compare performance of CBS-based detection with that of single quantitative MR imaging parameters. Materials and Methods Institutional review board approval and informed consent were obtained. Patients with a diagnosis of prostate cancer underwent multiparametric MR imaging before surgery for treatment. All MR imaging voxels in the prostate were classified as cancer or noncancer on the basis of coregistered histopathologic data. Predictive models were developed by using more than one quantitative MR imaging parameter to generate CBS maps. Model development and evaluation of quantitative MR imaging parameters and CBS were performed separately for the peripheral zone and the whole gland. Model accuracy was evaluated by using the area under the receiver operating characteristic curve (AUC), and confidence intervals were calculated with the bootstrap procedure. The improvement in classification accuracy was evaluated by comparing the AUC for the multiparametric model and the single best-performing quantitative MR imaging parameter at the individual level and in aggregate. Results Quantitative T2, apparent diffusion coefficient (ADC), volume transfer constant (K(trans)), reflux rate constant (kep), and area under the gadolinium concentration curve at 90 seconds (AUGC90) were significantly different between cancer and noncancer voxels (P < .001), with ADC showing the best accuracy (peripheral zone AUC, 0.82; whole gland AUC, 0.74). Four-parameter models demonstrated the best performance in both the peripheral zone (AUC, 0.85; P = .010 vs ADC alone) and whole gland (AUC, 0.77; P = .043 vs ADC alone). Individual-level analysis showed statistically significant improvement in AUC in 82% (23 of 28) and 71% (24 of 34) of patients with peripheral-zone and whole-gland models, respectively, compared with ADC alone. Model-based CBS maps for cancer detection showed improved visualization of cancer location and extent. Conclusion Quantitative multiparametric MR imaging models developed by using coregistered correlative histopathologic data yielded a voxel-wise CBS that outperformed single quantitative MR imaging parameters for detection of prostate cancer, especially when the models were assessed at the individual level. (©) RSNA, 2016 Online supplemental material is available for this article.

Use of MRI for Lobar Classification of Benign Prostatic Hyperplasia: Potential Phenotypic Biomarkers for Research on Treatment Strategies.

OBJECTIVE: We present an MRI classification of benign prostatic hyperplasia (BPH) for use as a phenotype biomarker in the study of proposed therapeutic interventions. CONCLUSION: Six patterns of BPH distribution were identified. Illustrations are provided for each classification type.

The importance and future of prostate MRI report templates: improving oncological care.

The radiologist's report is crucial for guiding care post-imaging, with ongoing advancements in report construction. Recent studies across various modalities and organ systems demonstrate enhanced clarity and communication through structured reports. This article will explain the benefits of disease-state specific reporting templates using prostate MRI as the model system. We identify key reporting components for prostate cancer detection and staging as well as imaging in active surveillance and following therapy. We discuss relevant reporting systems including PI-QUAL, PI-RADS, PRECISE, PI-RR and PI-FAB systems. Additionally, we examine optimal reporting structure including disruptive technologies such as graphical reporting and using artificial intelligence to improve report clarity and applicability.

Transplantation for type 1 diabetes: radiologist's primer on islet, pancreas and pancreas-kidney transplantation imaging.

Whole-organ pancreas, pancreatic-kidney and islet transplantation are surgical therapeutic options for the treatment of type 1 diabetes. They can enable effective glycemic control, improve quality of life and delay/reduce the secondary complications of type 1 diabetes mellitus. Radiologists are integral members of the multidisciplinary transplantation team involved in these procedures, with multimodality imaging serving as the mainstay for early recognition and management of transplant related complications. This review highlights the transplantation procedures available for patients with type 1 Diabetes Mellitus with a focus on the imaging appearance of transplantation-related complications.

Transurethral Vapor Ablation in Patients with Intermediate-Risk Localized Prostate Cancer.

Purpose: We report results of a prospective, multicenter single-arm study of transurethral vapor ablation (TUVA) of prostate tissue in patients with unilateral, intermediate-risk, localized prostate cancer (PCa). Materials and Methods: Men ≥45 years of age with biopsy-confirmed unilateral Gleason grade group 2 (GGG2) adenocarcinoma of the prostate, prostate volume of 20-80 cc, and prostate-specific antigen (PSA) ≤15 ng/mL were enrolled. Cystoscopy and transrectal ultrasound (TRUS) guidance were used to deliver ∼103°C water vapor to prostate zones for unilateral hemigland ablation, including destruction of cancers detected by multiparametric MRI (mpMRI) and confirmed by biopsy. The primary outcomes were device-related serious adverse events (SAEs). At 7 days and 6 months postprocedure, the ablation extent was assessed by mpMRI; MRI/TRUS fusion biopsies were completed at 6 months. Quality of life (QOL) was assessed with validated questionnaires. Results: All subjects underwent a single hemigland TUVA procedure. No SAEs occurred. Grade 2 procedure-related AEs included transient urinary retention (n = 4) and erectile (n = 1) or ejaculatory dysfunction (n = 1). At 7 days, mpMRI revealed complete ablation of 14/17 (82%) visible lesions. At 6 months, biopsies showed no Gleason pattern ≥4 or ≥GGG2 cancer on the treated side of prostates in 13/15 (87%) subjects. Ten of 15 (67%) subjects were biopsy negative. Of the 5 biopsy-negative subjects, 2 had one core each of 3 + 4 disease and 3 had one core each of 3 + 3 disease with ≤5% involvement. Median prostate volume was reduced by 40.7% and PSA by 58%. Extensive QOL assessments showed, on average, no appreciable negative effects of treatment. Conclusions: Initial evidence suggests that TUVA is safe in men with intermediate-risk PCa. Preliminary results demonstrate the absence of ≥GGG2 disease on the treated side in 87% of men and a favorable QOL profile.

AUR-RRA Review: Logistics of Academic-Industry Partnerships in Artificial Intelligence.

The Radiology Research Alliance (RRA) of the Association of University Radiologists (AUR) convenes Task Forces to address current topics in radiology. In this article, the AUR-RRA Task Force on Academic-Industry Partnerships for Artificial Intelligence, considered issues of importance to academic radiology departments contemplating industry partnerships in artificial intelligence (AI) development, testing and evaluation. Our goal was to create a framework encompassing the domains of clinical, technical, regulatory, legal and financial considerations that impact the arrangement and success of such partnerships.

Design and Rationale for the Use of Magnetic Resonance Imaging Biomarkers to Predict Diabetes After Acute Pancreatitis in the Diabetes RElated to Acute Pancreatitis and Its Mechanisms Study: From the Type 1 Diabetes in Acute Pancreatitis Consortium.

ABSTRACT: This core component of the Diabetes RElated to Acute pancreatitis and its Mechanisms (DREAM) study will examine the hypothesis that advanced magnetic resonance imaging (MRI) techniques can reflect underlying pathophysiologic changes and provide imaging biomarkers that predict diabetes mellitus (DM) after acute pancreatitis (AP). A subset of participants in the DREAM study will enroll and undergo serial MRI examinations using a specific research protocol. The aim of the study is to differentiate at-risk individuals from those who remain euglycemic by identifying parenchymal features after AP. Performing longitudinal MRI will enable us to observe and understand the natural history of post-AP DM. We will compare MRI parameters obtained by interrogating tissue properties in euglycemic, prediabetic, and incident diabetes subjects and correlate them with metabolic, genetic, and immunological phenotypes. Differentiating imaging parameters will be combined to develop a quantitative composite risk score. This composite risk score will potentially have the ability to monitor the risk of DM in clinical practice or trials. We will use artificial intelligence, specifically deep learning, algorithms to optimize the predictive ability of MRI. In addition to the research MRI, the DREAM study will also correlate clinical computed tomography and MRI scans with DM development.

A Fatal Case of Diffuse Alveolar Hemorrhage in the Setting of Systemic Lupus Erythematosus: A Case Report and Review of Noninfectious Causes of Acute Pulmonary Hemorrhage in Adults.

Systemic lupus erythematosus (SLE) is an autoimmune connective tissue disease, characterized by autoantibody production and immune complex formation, that has the potential to affect virtually any organ. Pleuropulmonary involvement occurs in 50-70% and commonly manifests as pleuritis and pleural effusion. Diffuse alveolar hemorrhage (DAH) is a rare manifestation of SLE. Most cases of DAH occur in young adults with an underlying autoimmune disease such as systemic vasculitis or Goodpasture syndrome. SLE is typically lower on the list of initial differential diagnoses of DAH due to its rarity compared to other etiologies. We present a case of a patient with dyspnea on exertion, dry coughs, lower extremity edema, and intermittent periorbital edema who ultimately succumbed to respiratory failure secondary to DAH in the setting of SLE. The diagnosis of SLE was suspected clinically and confirmed at autopsy due to her rapid clinical deterioration. DAH requires prompt intervention, and management is guided by the underlying disease process. SLE is a potentially treatable disease; therefore, timely diagnosis is important in order to exclude other noninfectious causes of DAH (reviewed in this report) and to initiate appropriate therapy.

Training Convolutional Networks for Prostate Segmentation With Limited Data.

Multi-zonal segmentation is a critical component of computer-aided diagnostic systems for detecting and staging prostate cancer. Previously, convolutional neural networks such as the U-Net have been used to produce fully automatic multi-zonal prostate segmentation on magnetic resonance images (MRIs) with performance comparable to human experts, but these often require large amounts of manually segmented training data to produce acceptable results. For institutions that have limited amounts of labeled MRI exams, it is not clear how much data is needed to train a segmentation model, and which training strategy should be used to maximize the value of the available data. This work compares how the strategies of transfer learning and aggregated training using publicly available external data can improve segmentation performance on internal, site-specific prostate MR images, and evaluates how the performance varies with the amount of internal data used for training. Cross training experiments were performed to show that differences between internal and external data were impactful. Using a standard U-Net architecture, optimizations were performed to select between 2D and 3D variants, and to determine the depth of fine-tuning required for optimal transfer learning. With the optimized architecture, the performance of transfer learning and aggregated training were compared for a range of 5-40 internal datasets. The results show that both strategies consistently improve performance and produced segmentation results that are comparable to that of human experts with approximately 20 site-specific MRI datasets. These findings can help guide the development of site-specific prostate segmentation models for both clinical and research applications.