Automated prostate multi-regional segmentation in magnetic resonance using fully convolutional neural networks.

OBJECTIVE: Automatic MR imaging segmentation of the prostate provides relevant clinical benefits for prostate cancer evaluation such as calculation of automated PSA density and other critical imaging biomarkers. Further, automated T2-weighted image segmentation of central-transition zone (CZ-TZ), peripheral zone (PZ), and seminal vesicle (SV) can help to evaluate clinically significant cancer following the PI-RADS v2.1 guidelines. Therefore, the main objective of this work was to develop a robust and reproducible CNN-based automatic prostate multi-regional segmentation model using an intercontinental cohort of prostate MRI. METHODS: A heterogeneous database of 243 T2-weighted prostate studies from 7 countries and 10 machines of 3 different vendors, with the CZ-TZ, PZ, and SV regions manually delineated by two experienced radiologists (ground truth), was used to train (n = 123) and test (n = 120) a U-Net-based model with deep supervision using a cyclical learning rate. The performance of the model was evaluated by means of dice similarity coefficient (DSC), among others. Segmentation results with a DSC above 0.7 were considered accurate. RESULTS: The proposed method obtained a DSC of 0.88 ± 0.01, 0.85 ± 0.02, 0.72 ± 0.02, and 0.72 ± 0.02 for the prostate gland, CZ-TZ, PZ, and SV respectively in the 120 studies of the test set when comparing the predicted segmentations with the ground truth. No statistically significant differences were found in the results obtained between manufacturers or continents. CONCLUSION: Prostate multi-regional T2-weighted MR images automatic segmentation can be accurately achieved by U-Net like CNN, generalizable in a highly variable clinical environment with different equipment, acquisition configurations, and population. KEY POINTS: • Deep learning techniques allows the accurate segmentation of the prostate in three different regions on MR T2w images. • Multi-centric database proved the generalization of the CNN model on different institutions across different continents. • CNN models can be used to aid on the diagnosis and follow-up of patients with prostate cancer.

Teleworking beyond teleradiology: managing radiology departments during the COVID-19 outbreak.

Teleradiology solutions are playing an essential role during the COVID-19 outbreak. Activity at radiology departments must be maintained and adapted to this new situation beyond teleradiology. Teleworking should be extended to the rest of non-medical radiology department areas. A comprehensive perspective based on our own experience during the COVID-19 outbreak has been performed highlighting the value of teleworking for almost all areas implied in the workflow of radiology departments beyond radiologists. Personal and technical requirements for successfully adapting to this new scenario are discussed including the opportunities that this unprecedent situation is bringing for reorganizing workflow and developing new projects. KEY POINTS: • Teleradiology solutions are playing an essential role during the COVID-19 outbreak. • Teleworking should be extended to the rest of non-medical radiology department areas whenever possible.

Improving Bone Mineral Density Assessment Using Spectral Detector CT.

INTRODUCTION: Bone mineral density (BMD) analysis by Dual-Energy x-ray Absorptiometry (DXA) can have some false negatives due to overlapping structures in the projections. Spectral Detector CT (SDCT) can overcome these limitations by providing volumetric information. We investigated its performance for BMD assessment and compared it to DXA and phantomless volumetric bone mineral density (PLvBMD), the latter known to systematically underestimate BMD. DXA is the current standard for BMD assessment, while PLvBMD is an established alternative for opportunistic BMD analysis using CT. Similarly to PLvBMD, spectral data could allow BMD screening opportunistically, without additional phantom calibration. METHODOLOGY: Ten concentrations of dipotassium phosphate (K2HPO4) ranging from 0 to 600 mg/ml, in an acrylic phantom were scanned using SDCT in four different, clinically-relevant scan conditions. Images were processed to estimate the K2HPO4 concentrations. A model representing a human lumbar spine (European Spine Phantom) was scanned and used for calibration via linear regression analysis. After calibration, our method was retrospectively applied to abdominal SDCT scans of 20 patients for BMD assessment, who also had PLvBMD and DXA. Performance of PLvBMD, DXA and our SDCT method were compared by sensitivity, specificity, negative predictive value and positive predictive value for decreased BMD. RESULTS: There was excellent correlation (R2 >0.99, p < 0.01) between true and measured K2HPO4 concentrations for all scan conditions. Overall mean measurement error ranged from -11.5 ± 4.7 mg/ml (-2.8 ± 6.0%) to -12.3 ± 6.3 mg/ml (-4.8 ± 3.0%) depending on scan conditions. Using DXA as a reference standard, sensitivity/specificity for detecting decreased BMD in the scanned patients were 100%/73% using SDCT, 100%/40% using PLvBMD provided T-scores, and 90-100%/40-53% using PLvBMD hydroxyapatite density classifications, respectively. CONCLUSIONS: Our results show excellent sensitivity and high specificity of SDCT for detecting decreased BMD, demonstrating clinical feasibility. Further validation in prospective clinical trials will be required.

Effect of Virtual Monoenergetic Images From Spectral Detector Computed Tomography on Coronary Calcium Blooming.

OBJECTIVE: The aim of this study was to investigate the quantitative and qualitative effects of virtual monoenergetic images (VMI) by spectral detector computed tomography (SDCT) on calcium blooming in coronary computed tomography angiography. METHODS: Coronary computed tomography angiography using SDCT was performed on 42 patients with coronary artery calcifications. Stenosis grading by diameter and area of calcified plaques and free lumen using VMI from 70 to 140 keV was performed and compared with measurements by conventional images. In addition, interobserver reliability and subjective image quality were assessed by 2 experienced readers. RESULTS: A total of 61 coronary arteries were evaluated. Stenosis grading by diameter and area showed significant incremental decrease, from 48.86% to 22.82% and from 41.18% to 11.33%, respectively, with increasing VMI (P < 0.05). Interobserver reliability was excellent (intraclass correlation coefficient >0.99). Overall image quality was best at 80 keV. CONCLUSIONS: Calcium blooming significantly decreases at higher monoenergetic levels from SDCT, increasing luminal dimensions and decreasing stenotic grading, with best overall subjective image quality using 80-keV VMI.

Magnetic resonance enterography/enteroclysis in acquired small bowel diverticulitis and small bowel diverticulosis.

PURPOSE: Small bowel (SB) diverticulosis is a rare disorder that may entail serious complications, including SB diverticulitis. Both are often missed in imaging. Magnetic resonance enterography/enteroclysis (MRE) is increasingly used to assess SB disease; awareness of the appearance of SB diverticulitis is essential to ensure appropriate management. Our aim was to systematically describe imaging characteristics of SB diverticulosis and diverticulitis in MRE. METHODS: This retrospective, HIPAA-compliant study identified 186 patients with suspected SB diverticulosis/diverticulitis in medical databases of two tertiary medical centres between 2005 and 2011. Patients with surgically confirmed diagnoses of SB diverticulosis/diverticulitis were included. Two observers analyzed MR images for the presence, location, number, and size of diverticula, wall thickness, and mural and extramural patterns of inflammation. RESULTS: Seven patients were recruited. MRI analysis showed multiple diverticula in all (100 %). Diverticular size ranged from 0.5 to 6 cm. Prevalence of diverticula was higher in the proximal than the distal SB (jejunum 86 %, ileum 57 %, distal ileum43%). Diverticulitis occurred in 3/7 patients (43 %) showing asymmetric bowel wall thickening and focal mesenteric inflammation. CONCLUSION: SB diverticulitis demonstrates characteristic MRE imaging features to distinguish this rare disorder from more common diseases. Asymmetric, focal mesenteric and mural inflammation and presence of multiple diverticula are keys to diagnosis. KEY POINTS: • Small bowel diverticulosis and diverticulitis is rare and often missed in imaging • Acquired small bowel diverticula are variable in size and number • Small bowel diverticulitis demonstrates characteristic features on MR enterography/enteroclysis • A focal or segmental asymmetric small bowel inflammation should prompt the search for diverticula.

Moving Away From Spoon-Feeding as a Teaching Style in Radiology.

OBJECTIVE: Medical education has been an important topic in the literature, with many new attempts to revitalize and improve efforts to teach physicians and students. As a unique subspecialty that incorporates visual learning, knowledge of clinical management and presentation, basic science topics such as physics and mechanics, and procedural skills, radiology affords itself to new and more effective methods of teaching. CONCLUSION: Much of radiology education has currently focused on the concept of spoon-feeding information from the teacher to the learners. This article outlines the dangers of this approach in radiology and offers solutions for educators to improve their teaching skills and use the potential afforded by the diversity of the field.

Initial experience of MR/PET in a clinical cancer center.

Magentic Resonance/positron emission tomography (PET) has been introduced recently for imaging of clinical patients. This hybrid imaging technology combines the inherent strengths of MRI with its high soft-tissue contrast and biological sequences with the inherent strengths of PET, enabling imaging of metabolism with a high sensitivity. In this article, we describe the initial experience of MR/PET in a clinical cancer center along with a review of the literature. For establishing MR/PET in a clinical setting, technical challenges, such as attenuation correction and organizational challenges, such as workflow and reimbursement, have to be overcome. The most promising initial results of MR/PET have been achieved in anatomical areas where high soft-tissue and contrast resolution is of benefit. Head and neck cancer and pelvic imaging are potential applications of this hybrid imaging technology. In the pediatric population, MR/PET can decrease the lifetime radiation dose. MR/PET protocols tailored to different types of malignancies need to be developed. After the initial exploration phase, large multicenter trials are warranted to determine clinical indications for this exciting hybrid imaging technology and thereby opening new horizons in molecular imaging.

Predictive value of pattern classification 24 hours after radiofrequency ablation of liver metastases on CT and positron emission tomography/CT.

PURPOSE: To assess a classification scheme for predicting local tumor progression (LTP) after radiofrequency (RF) ablation of liver metastases, using predefined patterns on contrast-enhanced computed tomography (CT) and positron emission tomography (PET) combined with CT (PET/CT) acquired 24 hours after RF ablation. MATERIALS AND METHODS: There were 45 metastases in 20 patients treated. After 24 hours, imaging of the ablation zones was performed with contrast-enhanced PET/CT. Three independent radiologists prospectively assessed contrast-enhanced CT and combined PET/CT images to identify three patterns: pattern I, no tissue enhancement or fluorodeoxyglucose uptake between the ablation zone and the liver parenchyma; pattern II, a rimlike pattern; and pattern III, a peripheral nodule. PET/CT images obtained after 8-10 weeks were evaluated for LTP. The patterns were analyzed for their sensitivity, specificity, positive predictive value, and negative predictive value for predicting LTP. RESULTS: Pattern I was most frequently observed (81% for contrast-enhanced CT and 61% for PET/CT) as well as for ablation zones that showed LTP (52% and 37%, respectively). Conversely, pattern II was observed for tumors that were completely ablated (6% and 29%, respectively). Patterns II and III together had the highest sensitivity for predicting LTP (48% and 63%, respectively); pattern III had the highest specificity (94% and 95%, respectively). For nodular patterns, test characteristics were better for PET/CT compared with contrast-enhanced CT, but the difference was not significant. Nodular patterns > 1 cm achieved high positive predictive value (both 100%). CONCLUSIONS: Inflammation and hyperemia can hinder interpretation on imaging 24 hours after RF ablation, especially on PET/CT. Nodular patterns around the ablation zone on early contrast-enhanced CT and PET/CT have a high predictive value for LTP and should be taken into account for disease management.

Atmospheric isoprene measurements reveal larger-than-expected Southern Ocean emissions.

Isoprene is a key trace component of the atmosphere emitted by vegetation and other organisms. It is highly reactive and can impact atmospheric composition and climate by affecting the greenhouse gases ozone and methane and secondary organic aerosol formation. Marine fluxes are poorly constrained due to the paucity of long-term measurements; this in turn limits our understanding of isoprene cycling in the ocean. Here we present the analysis of isoprene concentrations in the atmosphere measured across the Southern Ocean over 4 months in the summertime. Some of the highest concentrations ( >500 ppt) originated from the marginal ice zone in the Ross and Amundsen seas, indicating the marginal ice zone is a significant source of isoprene at high latitudes. Using the United Kingdom Earth System Model we show that current estimates of sea-to-air isoprene fluxes underestimate observed isoprene by a factor >20. A daytime source of isoprene is required to reconcile models with observations. The model presented here suggests such an increase in isoprene emissions would lead to >8% decrease in the hydroxyl radical in regions of the Southern Ocean, with implications for our understanding of atmospheric oxidation and composition in remote environments, often used as proxies for the pre-industrial atmosphere.

The cost of doing business in academic radiology departments.

This study identifies the major sources of overhead fees/costs and subsidies in academic radiology departments (ARDs) in the US and determines the differences between them based on geographic location or the size of their affiliated hospital. ARDs in the Northeast had the highest level of financial support from their affiliated hospitals when compared to those in the South/Southwest; however, a greater number of Midwest ARDs receive high levels of funding for teaching from their medical schools when compared to the northeast. Significantly fewer ARDs affiliated with hospitals of less than 200 beds receive subsidies for their activities when compared to those affiliated with larger hospitals. Differences in levels of overhead costs/ subsidies available to ARDs are associated with either geographic location or the size of the affiliated hospital. The reasons for these differences may be related to a variety of legal, contractual, or fiscal factors. Investigation of existing geographic and affiliate size fiscal differences and their causes by ARDs may be of benefit.

The 2022 AUR Academic Radiology and Industry Leaders Roundtable.

The Association of University Radiologists (AUR) convened its sixth annual Academic-Industry Roundtable in a hybrid fashion in March 2022, with academic radiology and radiology industry leaders gathered in person and via remote videoconference. The open discussion centered around on challenges facing radiology and specifically focused on the people in our field, including patients, radiologists, and radiology staff. Participants identified numerous opportunities for industry and radiology departments to collaborate to improve equitable access to healthcare, communication with patients, use of appropriate imaging, and the state of the radiology workforce.

A Review of COVID-19's Impact on Radiology Residents' Academics and Wellness in North America.

BACKGROUND: The COVID-19 pandemic caused major disruptions in radiology departments throughout North America. Radiology residency programs were forced to make dramatic changes to their training programs, which had major impacts on resident academics and wellness. The goal of this review is to evaluate the impact of COVID-19 on radiology residents' academics and wellness in North America, while also identifying effective measures taken by programs to mitigate the effects of the pandemic. METHODS: The search strategy involved database search via PubMed, Embase, and Web of Science with specific key words related to COVID-19, radiology residents, education, wellness, and virtual learning. Studies discussing the education and wellness of radiology residents in North America published after 2020 were included. The data were analyzed using a narrative synthesis approach. RESULTS: The three main domains affected by the pandemic include the residency curriculum, research, and resident wellness. The decline in case volume and diversity of cases had negative overall impact on education of radiology residents, but simulated cases and virtual learning proved its value during the pandemic and may have lasting implications for the postpandemic world. Research initiatives transitioned to a remote format with greater emphasis on quality improvement and COVID-19-related studies. Reduced face-to-face interaction opportunities made it difficult to establish strong and meaningful interpersonal connections and had a negative impact on resident wellness, mentorship, and professional development. Implementing mentorship programs and virtual "town hall meetings" were effective measures to maintain connections during times of social distancing. Finally, the COVID-19 pandemic introduced unprecedented stressors and challenges for radiology residents that negatively impacted their mental health and wellness. Incorporating wellness initiatives such as wellness hours and team-building activities and using social media were helpful in promoting wellness and mental health for radiology residents. CONCLUSION: The COVID-19 pandemic has had a significant impact on the academics and wellness of radiology residents across North America but has taught us many lessons that can help us navigate the ongoing challenges of the pandemic, the postpandemic world, and future pandemics.

A history of radiologic pathology correlation at the Armed Forces Institute of Pathology and its evolution into the American Institute for Radiologic Pathology.

The evolution of the Armed Forces Institute of Pathology (AFIP) has played an important role in the history of pathology education and in radiologic pathology correlation in the United States. From its humble beginnings as a museum, showcasing dried and varnished morbid specimens--human relics of the Civil War, the institute became a leader in pathology. Later, it became a center of instruction for radiology residents seeking to understand the pathologic findings that underlay the radiologic appearance of disease. Images were gathered by the AFIP and the American Registry of Pathology (ARP) and have been used in research and education in radiology and other fields (ophthalmology, otalaryngology, dermatology, obstetrics and gynecology, and surgery). Despite the contributions of the AFIP, the ARP, and the Radiologic Pathology Correlation Course, high-ranking members of the military and the federal government frowned on a military-owned educational system that also served civilians. Although support from the radiology community dissuaded military officers and federal officials from taking action against the participation of civilians, the 2005 Base Realignment and Closure (BRAC) provisions mandated the disestablishment of the AFIP, forcing the redistribution of some of its resources to other military-only organizations and disbanding other AFIP functions. To ensure that the correlation course, known to radiology residents as the "rad-path" course, was not a casualty of the BRAC, the American College of Radiology (ACR) and leaders of the AFIP and ARP agreed that the ACR should continue this vital educational endeavor. In January 2011, the American Institute for Radiologic Pathology of the ACR debuted and successfully instructed 268 radiology residents, including 40 international residents. The faculty and staff, who had been part of the course at the AFIP, continue to help enrich and improve the course established by their predecessors.

The Radiology Landscape after COVID-19: Summary of the 2021 AUR Academic Radiology and Industry Leaders Roundtable.

The fifth Association of University Radiologists (AUR) Academic Radiology and Leaders Roundtable took place the day after the conclusion of the AUR annual meeting in May 2021 and involved leaders in academic radiology departments across the United States, and industry from companies who provide quintessential services to radiology departments. The open-ended discussion identified the key challenges facing the practice and business of radiology as we jointly move forward after the COVID-19 pandemic. Particular attention was paid to the identification of viable solutions that radiology departments should embrace to sustain clinical productivity, innovation, and well-being, and the ways that industry could contribute significantly to that endeavor.

A Systematic Review for Health Disparities and Inequities in Multiparametric Magnetic Resonance Imaging for Prostate Cancer Diagnosis.

RATIONALE AND OBJECTIVES: Multi-parametric Magnetic Resonance Imaging (mpMRI) is a novel procedure recommended by the American Urological Association for Prostate Cancer (PCa) diagnosis. In radiology, differences in utilization of expensive screening techniques are described but never reviewed for mpMRI. Thus, our article aims at summarizing disparities relating to the expensive yet revolutionary mpMRI in United States men with PCa while highlighting needed research areas. MATERIAL AND METHODS: Eligible articles were gathered via PubMed query, referred publications known to the authors or from the reference lists of the identified publications. We excluded studies that didn't specifically evaluate mpMRI technique, weren't conducted in the United States, or didn't directly assess the relationship between disparities and mpMRI. No date restrictions were applied, resulting articles were published through 2020. RESULTS: Out of 80 publications, 17 were selected. Two unique themes were identified: 1) disparities in mpMRI utilization, and 2) performance. While demographic factors such as race, age and socioeconomic status played a significant role in utilization, mpMRI demonstrated equal and sometimes superior performance in AAs. CONCLUSION: Our findings illustrate the importance of disparity awareness in PCa mpMRI and highlight the need to examine additional mpMRI disparities across other races and social determinants. A new area of inequity in PCa was theoretically illustrated, as lower utilization of mpMRI was detected in a group that could potentially benefit from it the most. Major limitation was the selected search terms. Our review is unique as disparities related to mpMRI were found to be multilayered, affecting utilization and performance. Continued research is needed to discover additional areas in efforts to reduce disparity gaps related to mpMRI and PCa.

Peritoneal sarcomatosis versus peritoneal carcinomatosis: imaging findings at MDCT.

OBJECTIVE: Peritoneal sarcomatosis is an entity analogous to the better known peritoneal carcinomatosis. The purpose of this article is to discuss the imaging findings of peritoneal sarcomatosis versus peritoneal carcinomatosis. CONCLUSION: Sarcomatosis is most commonly seen in gastrointestinal stromal tumor, liposarcoma, and leiomyosarcoma. A few distinguishing features of peritoneal sarcomatosis include heterogeneous bulky masses, hypervascularity with or without hemoperitoneum, and variable presence of ascites.

Recurrent malignant peritoneal mesothelioma: radiological manifestations.

PURPOSE: To describe the CT imaging findings of recurrent malignant peritoneal mesothelioma in patients who underwent debulking surgery. MATERIALS AND METHODS: The history, clinical and laboratory data, and imaging studies of 13 patients with histologically proven diagnosis of Malignant Peritoneal Mesothelioma (MPM) and their recurrence following cytoreductive surgery were reviewed. CT studies were reviewed for presence of ascites, peritoneal, mesenteric and omental involvement, presence of solid abdominal viscera involvement, gastrointestinal involvement, presence and location of enlarged lymph nodes and extra abdominal sites of involvement. RESULTS: The most common finding at recurrence was ascites (n = 6). Peritoneal thickening was seen in five patients, infiltration of the peritoneum resembling omental caking was seen in one patient, and low density implants mimicking pseudomyxoma peritonei was seen in another patient. None of the peritoneal implants showed calcification. Three patients had large discrete soft tissue masses in the omentum and/or peritoneum. Multifocal serosal implants were seen in four patients; one had low grade small bowel obstruction which was managed conservatively. Three patients had evidence of intrathoracic disease seen as soft tissue pericardial mass and malignant pleural effusions. CONCLUSION: CT findings of recurrent MPM resemble primary MPM, metastatic or granulomatous diseases. Radiologist should be aware of its appearance and forms of recurrence which may be seen at extra abdominal sites.

Artificial Intelligence in Radiology: Summary of the AUR Academic Radiology and Industry Leaders Roundtable.

The AUR Academic Radiology and Industry Leaders Roundtable was organized as an open discussion between academic leaders of top US academic radiology departments and industry leaders from top companies that provide equipment and services to radiology, including manufacturers, pharmaceutical companies, software developers and electronic medical record (EMR) providers. The format was that of a structured brainstorming session with pre-selected discussion topics. This roundtable was instrumental in widening perspectives and providing insights into the challenges and opportunities for our specialty, such as in the case of Artificial Intelligence (AI).