Anatomic Basis of Rectal Cancer Staging: Clarifying Controversies and Misconceptions.

Rectal MRI provides a detailed depiction of pelvic anatomy; specifically, the relationship of the tumor to key anatomic structures, including the mesorectal fascia, anterior peritoneal reflection, and sphincter complex. However, anatomic inconsistencies, pitfalls, and confusion exist, which can have a strong impact on interpretation and treatment. These areas of confusion include the definition of the rectum itself, specifically differentiation of the rectum from the anal canal and the sigmoid colon, and delineation of the high versus low rectum. Other areas of confusion include the relative locations of the mesorectal fascia and peritoneum and their significance in staging and treatment, the difference between the mesorectal fascia and circumferential resection margin, involvement of the sphincter complex, and evaluation of lateral pelvic lymph nodes. The impact of these anatomic inconsistencies and sources of confusion is significant, given the importance of MRI in depicting the anatomic relationship of the tumor to critical pelvic structures, to triage surgical resection and neoadjuvant chemoradiotherapy with the goal of minimizing local recurrence. Evolving treatment paradigms also place MRI central in management of rectal cancer. ©RSNA, 2024.

Evaluation of 18 CT signs in diagnosing cecal volvulus: a multi-reader retrospective study.

PURPOSE: To assess the diagnostic performance and reliability of 18 CT signs to diagnose cecal volvulus, a surgical emergency, versus a group of non-volvulus mimickers. MATERIALS AND METHODS: Four radiologists retrospectively and independently assessed 18 CT signs in 191 patients with cecal volvulus (n = 63) or a non-volvulus control group ((n = 128), including cecal bascule (n = 19), mobile cecum (n = 95), and colonic pseudo-obstruction (n = 14)) at a single institution from 2013 to 2021. Fleiss' kappa coefficient was used to assess inter-reader agreement. For diagnostic performance metrics, we assessed sensitivity, specificity, and positive and negative predictive values. For predictive performance, all 18 signs were included in bivariate and stepwise lasso multivariate logistic regression models to diagnose cecal volvulus. Performance was assessed by ROC curves. RESULTS: 191 patients (mean age: 63 years +/- 15.5 [SD]; 135 women) were included in the study. Nine of the 18 CT signs of cecal volvulus demonstrated good or better (> 0.6) inter-reader agreement. Individual CT signs with sensitivity, specificity, positive and negative predictive values all above 70% for diagnosing cecal volvulus were transition point, bird beak, and X-marks-the-spot. A lasso regression model determined four CT features: transition point, bird beak, coffee bean, and whirl had excellent prediction (AUC = .979) for cecal volvulus if all present. CONCLUSION: CT signs for cecal volvulus that have high sensitivity and specificity include: transition point, bird beak, and X-marks-the-spot and were reliable in distinguishing non-volvulus mimickers. If the following four features were present: transition point, bird beak, coffee bean, and whirl, there was excellent prediction (AUC = .979) for cecal volvulus.

The utility of [18F]Fluciclovine PET/CT in Evaluating Nonmetastatic Castrate-Resistant Prostate Cancer Patients (nmCRPCp): diagnostic performance and impact on management.

OBJECTIVE: To evaluate the role of [18F]Fluciclovine PET/CT scan in restaging nmCRPCp and its impact on management. METHODS AND MATERIALS: This retrospective study included all patients with nonmetastatic castrate-resistant prostate cancer, who underwent [18F]Fluciclovine PET/CT scans for restaging who had concern for disease progression. Two radiologists independently reviewed the PET/CT studies, assigned an overall impression, and reported the site and number of radiotracer activities in consensus and impact on management was recorded. Available tissue diagnosis and/or six-month clinical and imaging follow-up were used as reference standards. RESULTS: Thirty-five patients were included in this study. At least one lesion was detected in 73% (26/35) of the scans. Management changed in 71% (25/35) of patients, (22 positives and three negative scans). 26.9% (7/26) of patients were found to have an oligometastatic disease. Based on the reference standards, the diagnostic performance of [18F]Fluciclovine PET/CT in detecting recurrence in nmCRCP has 86%, sensitivity, 83% specificity, 96.1% PPV, and 55.5% NPV. There was no relationship between the Gleason score and a positive PET/CT scan in our patient population. CONCLUSION: Detecting the source of recurrence is challenging in nmCRCP patients when conventional imaging fails. Given the high PPV, sensitivity, and specificity, [18F]Fluciclovine PET/CT can be used instead of conventional imaging as a first-line choice due to its superiority over bone scan and added value of detecting soft tissue metastasis regardless of the initial Gleason score. ADVANCES IN KNOWLEDGE: The study highlights the added value of [18F]Fluciclovine PET/CT in detecting soft tissue metastasis regardless of the initial Gleason score, which is not possible with conventional imaging such as bone scans.The study highlights the potential role of [18F]Fluciclovine PET/CT guiding management change for nonmetastatic castrate-resistant prostate cancer patients, particularly those with oligometastatic disease.

Resident Perspective of the Virtual Diagnostic Radiology Residency Interview Process: A National Survey From the Association of Program Directors in Radiology.

RATIONALE AND OBJECTIVES: The purpose of this study was to assess differences in first-year radiology resident perception of the match process and early satisfaction with residency programs between those who matched in 2020 versus 2021, the first virtual application cycle after the start of the COVID-19 pandemic. MATERIALS AND METHODS: A 33-question survey was distributed to first-year diagnostic radiology residents at programs throughout the United States through the Association of Program Directors in Radiology. Responses were collected in June of 2022 from residents who matched in 2020 and in July of 2022 from residents who matched in 2021. Questions were designed to assess applicant demographics, outcomes and attitudes towards the interview process. Comparison was made between the two cohorts. RESULTS: Of the 2231 matched residents in the 2020 and 2021 match years, 108 residents (4.8%) received, responded, and met inclusion criteria for the survey. Forty-three of 46 (92.5%) respondents that matched in 2020 interviewed in-person compared to one of 60 (1.7%) that matched in 2021 (p < 0.0001). There was no difference in satisfaction of match results, current training programs, work culture, satisfaction with facilities, and depiction of residency structure. Applicants from the 2021 cohort were more likely to express concerns about interview hoarding, having enough time to ask questions on interview days, and ability to accurately present themselves in interviews but were more likely to favor virtual interviews for future cycles. CONCLUSION: The virtual interview process is perceived neutrally or positively by most early diagnostic radiology residents and produced similar satisfactory results compared to applicants that interviewed in person. Attention should be given to concerns of those who matched virtually if the virtual interview process is to be continued.

Teaching with Technology-Matching Pedagogy with Purpose in Radiology Education.

The response to pandemic-related teaching disruption has revealed dynamic levels of learning and teaching flexibility and rapid technology adoption of radiology educators and trainees. Shutdowns and distancing requirements accelerated the adoption of technology as an educational tool, in some instances supplanting in-person education entirely. Despite the limitations of remote interaction, many educational advantages were recognized that can be leveraged in developing distance learning paradigms. The specific strategies employed should match modern learning science, enabling both students and educators to mutually grow as lifelong learners. As panel members of the "COVID: Faculty perspective" Task Force of the Association of University Radiologists Radiology Research Alliance, we present a review of key learning principles which educators can use to identify techniques that enhance resident learning and present an organized framework for applying technology-aided techniques aligned with modern learning principles. Our aim is to facilitate the purposeful integration of learning tools into the training environment by matching these tools to established educational frameworks. With these frameworks in mind, radiology educators have the opportunity to re-think the balance between traditional curricular design and modern digital teaching tools and models.

"Imaging Findings of Eosinophilic Gastrointestinal Diseases in Adults".

Eosinophilic gastrointestinal (GI) disorders are a group of conditions marked by pathologic eosinophilic infiltration of one or multiple locations in the GI tract. Conditions include eosinophilic esophagitis, eosinophilic gastritis, eosinophilic enteritis, and eosinophilic colitis. The site and depth of eosinophilic infiltration of the GI tract usually determines clinical presentation. These conditions should be considered in the differential diagnosis for several GI symptoms, such as food impaction or dysphagia. Histopathology is the gold standard for diagnosis of eosinophilic disorders. Nevertheless, findings from endoscopy, barium studies, computed tomography or magnetic resonance imaging, can aid in the diagnosis, by allowing for earlier diagnosis as well as proper management. Eosinophilic gastrointestinal disorders are typically managed with corticosteroids or dietary elimination. A high index of suspicion is required for diagnosis as it can often be challenging.

A Framework for Harmonization of Radiomics Data for Multicenter Studies and Clinical Trials.

PURPOSE: Variability in computed tomography images intrinsic to individual scanners limits the application of radiomics in clinical and research settings. The development of reproducible and generalizable radiomics-based models to assess lesions requires harmonization of data. The purpose of this study was to develop, test, and analyze the efficacy of a radiomics data harmonization model. MATERIALS AND METHODS: Radiomic features from biopsy-proven untreated hepatic metastasis (N = 380) acquired from 167 unique patients with pancreatic, colon, and breast cancers were analyzed. Radiomic features from volume-match 551 samples of normal liver tissue and 188 hepatic cysts were included as references. A novel linear mixed effect model was used to identify effects associated with lesion size, tissue type, and scanner model. Six separate machine learning models were then used to test the effectiveness of radiomic feature harmonization using multivariate analysis. RESULTS: Proposed model identifies and removes scanner-associated effects while preserving cancer-specific functional dependence of radiomic features on the tumor size. Data harmonization improves the performance of classification models by reducing the scanner-associated variability. For example, the multiclass logistic regression model, LogitBoost, demonstrated the improvement in sensitivity in the range from 15% to 40% for each type of liver metastasis, whereas the overall model accuracy and the kappa coefficient increased by 5% and 8% accordingly. CONCLUSION: The model removed scanner-associated effects while preserving cancer-specific functional dependence of radiomic features.

Utilizing CT to identify clinically significant biliary dilatation in symptomatic post-cholecystectomy patients: when should we be worried?

PURPOSE: To determine a reliable threshold common duct diameter on CT, in combination with other ancillary CT and clinical parameters, at which the likelihood of pathology requiring further imaging or intervention is increased in post-cholecystectomy patients. METHODS: In this IRB approved retrospective study, two attending radiologists independently reviewed CT imaging for 118 post-cholecystectomy patients, who were subsequently evaluated with MRCP, ERCP, or EUS, prompted by findings on the CT and clinical status. Measurements of the common duct (CD) were obtained at the porta hepatis, distal duct, and point of maximal dilation on axial and coronal CT scans. Patients were grouped by whether they required intervention after follow-up imaging. Pertinent baseline lab values and patient demographics were reviewed. RESULTS: Of the 118 post-cholecystectomy patients, 38 patients (31%) required intervention, and 80 patients (69%) did not require intervention after follow-up imaging. For both readers, axial and coronal CD diameters were significantly higher in the 'intervention required' vs 'no intervention' groups at all locations (p value < 0.05). There was good to excellent inter-reader agreement at all locations (ICC 0.68-0.92). Pertinent baseline lab values including AST (p = 0.043), ALT (p = 0.001), alkaline phosphatase (p = 0.0001), direct bilirubin (p = 0.011), total bilirubin (p = 0.028), and WBC (p = 0.043) were significantly higher in the 'intervention required' group. CD thresholds of 8 mm yielded the highest sensitivities (76-95%), and CD thresholds of 12 mm yielded the highest specificities (65-78%). CD combined with bilirubin levels increased sensitivity and specificity, compared to using either feature alone. CONCLUSION: Dilated CD on CT combined with bilirubin levels increases the sensitivity and specificity for identifying patients needing intervention. We recommend that a post-cholecystectomy patient who presents with a CD diameter > 10 mm on CT and elevated bilirubin levels should undergo further clinical and imaging follow-up.

Association of CT findings in patients with hemoperitoneum due to ruptured ovarian cysts with subsequent intervention.

PURPOSE: Hemoperitoneum caused by ovarian cyst rupture may necessitate intervention. The literature is lacking in descriptions of CT findings that help guide patient management. The purpose of this study is to consider CT findings associated with a need for intervention (surgical or interventional radiology management) versus conservative treatment (observation, pain management, and blood transfusions). METHODS: Two radiologists retrospectively and independently reviewed 103 CTs of pre-menopausal women who presented with acute hemoperitoneum related to ruptured ovarian cysts between January 2010 and January 2019. The following imaging features were assessed: ovarian cyst characteristics, sentinel clot, contrast extravasation, and hemoperitoneum size. Findings were correlated with patient demographics, clinical parameters, and management with surgery/interventional radiology procedure (intervention group) versus conservative management (conservative group). RESULTS: Of the 103 patients with hemoperitoneum from cyst rupture, 16% (n = 16) required intervention, and 84% underwent conservative treatment (n = 87). Length of stay (p = .008) was higher in the intervention group. Statistically significant CT findings in the intervention versus conservative group included (p-value reader 1/p-value reader 2) greatest AP dimension of hemoperitoneum (p = .001/p = 0.02), posterior cul-de-sac AP dimension (p = 0.03/p = .006), total cul-de-sac AP dimension (p = .002/p = .007), and number of spaces with hemoperitoneum (p = .01/p = .02). There was good to excellent inter-reader agreement for these findings (ICC 0.68-0.91). Active contrast extravasation was significant for one reader (p = .02) with poor inter-reader agreement (ICC 0.36). In utilizing ROC curves, thresholds of 107 mm (greatest axial AP dimension of hemoperitoneum) yielded a sensitivity and specificity of 0.81 and 0.62 for reader 1 and 0.69 and 0.55 for reader 2; 45 mm (posterior cul-de-sac AP dimension) yielded a sensitivity and specificity of 0.75 and 0.63 for reader 1 and 0.94 and 0.49 for reader 2; 70 mm (total cul-de-sac AP dimension) yielded a sensitivity and specificity of 0.75 and 0.64 for reader 1 and 0.75 and 0.50 for reader 2; and greater than 5 spaces yielded a sensitivity and specificity of 0.75 and 0.58 for reader 1 and 0.69 and 0.70 for reader 2. CONCLUSION: CT findings associated with intervention in hemoperitoneum due to ovarian cyst rupture include size of hemoperitoneum, number of abdominopelvic spaces with hemoperitoneum, and contrast extravasation.

Role of hepatic metastatic lesion size on inter-reader reproducibility of CT-based radiomics features.

OBJECTIVES: To evaluate the effect of hepatic metastatic lesion size on inter-reader reproducibility of CT-based 2D radiomics imaging features. METHODS: Computerized tomography (CT) scans of 59 liver metastases from 34 patients with colorectal cancer were evaluated. Image segmentation was performed manually by three readers blinded to each other's results. For each radiomics feature, we created two datasets by sorting measurements according to size, i.e., (i) from the smallest to the largest lesion and (ii) from the largest to the smallest lesion. The Lin concordance correlation coefficient (CCC) was employed to analyze the reproducibility of radiomics features. In particular, the CCC was computed as a function of a number of elements in the dataset, by gradually adding lesions from each sorted dataset. To evaluate the effect of lesion size, we analyzed the difference between these two functions thus assessing the contribution of small and large lesions into the reproducibility of radiomics features. RESULTS: Inter-reader reproducibility of CT-based 2D radiomics features assessed using Lin's CCC demonstrates tumor-size dependence. For example, the Lin CCC for GLCM contrast equals 0.88 (95% C.I. 0.84 to 0.92, p < 0.003) and could change by an additional + / - 0.06 depending on the presence of large or small lesions. CONCLUSIONS: Groups of "large" and "small" lesions show different inter-reader reproducibility. The inter-reader reproducibility from the mixed group consisting of "large" and "small" lesions depends on the lesion-size distribution and can vary widely. This finding could partially explain variability in reproducibility of radiomics features in the literature. KEY POINTS: • Groups of "large" and "small" lesions show different inter-reader reproducibility. • The inter-reader reproducibility from the mixed group consisting of "large" and "small" lesions depends on the lesion-size distribution.

Role of Ergonomic Improvements in Decreasing Repetitive Stress Injuries and Promoting Well-Being in a Radiology Department.

RATIONALE AND OBJECTIVES: To determine if ergonomic improvements in a radiology department can decrease repetitive stress injuries (RSIs), advance ergonomics knowledge, and improve well-being. MATERIALS AND METHODS: Radiologists in an academic institution were surveyed regarding physician wellness, workstations, RSIs, and ergonomics knowledge before and after interventions over 1 year. Interventions included committee formation, education, wrist pads and wireless mice, broken table and chair replacement, and cord organization. Mann-Whitney U test was used for analysis. RESULTS: Survey response was 40% preinterventions (59/147), and 42% (66/157) postinterventions. Preinterventions, of radiologists with RSI history, 17/40 (42%) reported the RSI caused symptoms which can lead to burnout, and 15/40 (37%) responded their RSI made them think about leaving their job. Twenty-three of 59 (39%) radiologists had an active RSI preinterventions. Postinterventions, 9/25 (36%) RSI resolved, 13/25 (52%) RSI improved, and 3/25 (12%) RSI did not improve. RSI improvements were attributed to ergonomic interventions in 19/25 (76%) and therapy in 2/25 (8%). Radiologists who thought their workstation was designed with well-being in mind increased from 9/59 (15%) to 52/64 (81%). The percentage of radiologists knowing little or nothing about ergonomics decreased from 15/59 (25%) to 5/64 (8%). After ergonomics interventions, more radiologists thought the administration cared about safety and ergonomics, equipment was distributed fairly, and radiologists had the ability to ask for equipment (p < .01). Fifty-three of 64 (83%) of radiologists after interventions said improving workstation ergonomic design contributed to well-being. CONCLUSION: Ergonomic improvements in radiology can decrease RSIs, advance ergonomics knowledge, and improve well-being.

Evolution of Radioembolization in Treatment of Hepatocellular Carcinoma: A Pictorial Review.

Transarterial radioembolization (TARE) with yttrium 90 has increasingly been performed to treat hepatocellular carcinoma (HCC). TARE was historically used as a palliative lobar therapy for patients with advanced HCC beyond surgical options, ablation, or transarterial chemoembolization, but recent advancements have led to its application across the Barcelona Clinic Liver Cancer staging paradigm. Newer techniques, termed radiation lobectomy and radiation segmentectomy, are being performed before liver resection to facilitate hypertrophy of the future liver remnant, before liver transplant to bridge or downstage to transplant, or as a definite curative treatment. Imaging assessment of therapeutic response to TARE is challenging as the intent of TARE is to deliver local high-dose radiation to tumors through microembolic microspheres, preserving blood flow to promote radiation injury to the tumor. Because of the microembolic nature, early imaging assessment after TARE cannot rely solely on changes in size. Knowledge of the evolving methods of TARE along with the tools to assess posttreatment imaging and response is essential to optimize TARE as a therapeutic option for patients with HCC. ©RSNA, 2021.

Review of Artificial Intelligence Training Tools and Courses for Radiologists.

Artificial intelligence (AI) systems play an increasingly important role in all parts of the imaging chain, from image creation to image interpretation to report generation. In order to responsibly manage radiology AI systems and make informed purchase decisions about them, radiologists must understand the underlying principles of AI. Our task force was formed by the Radiology Research Alliance (RRA) of the Association of University Radiologists to identify and summarize a curated list of current educational materials available for radiologists.

Optimizing detection of postoperative leaks on upper gastrointestinal fluoroscopy: a step-by-step guide.

Postoperative leaks after gastrointestinal surgery are important to identify to decrease patient morbidity and mortality. Fluoroscopic studies are commonly employed to detect postoperative leak. While the literature addresses the sensitivity and specificity of these examinations, there is generally a lack of description of the fluoroscopic technique itself and there may be variability between radiologists in how these studies are performed. It is important to balance a standardized fluoroscopy protocol while tailoring the exam for each surgical and patient situation. Here we will briefly review common postoperative anatomy in the upper gastrointestinal tract, propose fluoroscopic techniques to improve postoperative leak detection, and illustrate teaching points with clinical cases.

Using Online Survey Software to Enhance Radiology Learning.

RATIONALE AND OBJECTIVES: Online educational modules can augment radiology learning by creating opportunities to interact with images in more dynamic ways than with static presentation of images in lectures or journal articles. Building these modules on an online survey platform allows for quantitative assessment and learner feedback, without requiring programming knowledge or need for new website creation. MATERIALS AND METHODS: Interactive online tutorials were built on a web-based survey platform (Qualtrics, Provo, Utah) accessible by computer or mobile device to teach radiology imaging findings of selected high-morbidity diagnoses. Topics included congenital-type internal hernias (module 1), acute appendicitis in the pregnant patient (module 2), and unintentionally retained surgical instruments (RSI; module 3). Modules consisted of pretest, educational module, and post-test components. For modules 1 and 2, graphics interchange formats were utilized to show CT and MRI image stacks for the diagnosis of congenital-type internal hernias and acute appendicitis in pregnant patients, respectively. For module 3, the "Heat Map" format was chosen to showcase intraoperative radiograph cases, which allowed participants to click on the potential RSI in the image. Pre- and post-test scores were evaluated. To determine statistical significance, an alpha level of 0.05 was utilized. RESULTS: Module 1 (Internal Hernia): Twenty-one radiology trainees completed the module. The mean pretest score was 3.66 (±1.13) points out of a total 6 possible points (61%), compared to 4.52 (±1.03) points on the post-test (75%). This was a statistically significant increase on the post-test of 0.87 points (95% CI [confidence interval] 0.36, 1.38), t(20) = 3.53, p= 0.002. Module 2 (MR Appendicitis): Seventeen radiology trainees completed the module. The mean pretest score was 3.18 (±1.42) points out of a total 6 possible points (53%), compared to 5.12 (±0.86) points on the post-test (85%). This was a statistically significant increase on the post-test of 1.94 points (95% CI 1.12, 2.76), t(16) = 5.00, p< 0.001. Module 3 (RSI): One hundred seven participants completed the module. The mean pretest score was 3.60 (±1.53) points out of a total 6 possible points (60%), compared to 4.54 (±1.36) points on the post-test (76%). This was a statistically significant increase on the post-test of 0.94 points (95% CI 0.67, 1.21), t(106) = 6.84, p< 0.001. CONCLUSION: An online survey platform can be used to build interactive education modules. Post-test scores significantly improved from pretest scores with these educational modules.

A review of internal hernias related to congenital peritoneal fossae and apertures.

Congenital-type internal hernias have the potential to cause small bowel obstruction well into adulthood. Congenital-type internal hernias include left paraduodenal, right paraduodenal, foramen of Winslow, pericecal, sigmoid mesocolon, transomental, small bowel mesentery, and broad ligament hernias. This review summarizes CT imaging features and complications of congenital internal hernias using a systematic approach based on abdominopelvic quadrants and key anatomic features. CT imaging will continue to be commonly used to evaluate abdominal pain. Anatomical landmarks and characteristic CT findings can help identify congenital internal hernias as a potential cause of abdominal pain.

Gastric outlet obstruction in the setting of acute cholecystitis.

Acute cholecystitis is a rare cause of gastric outlet obstruction (GOO) and may manifest with nonspecific symptoms which may preclude or delay diagnosis. During the latter part of the 20th century, benign disease was responsible for most cases of GOO in adults with peptic ulcer disease accounting for up to 90% of these cases. Although precise estimates on GOO incidence and prevalence are lacking, as many as 2000 surgical operations were reportedly performed annually for GOO in the United States in the 1990s. We present clinical and imaging findings of a case of a 101-year-old woman with GOO resulting from extrinsic compression from a massively dilated gallbladder related to acute cholecystitis. In addition, we review other rare biliary causes of GOO.

Inflammatory mimickers of pancreatic adenocarcinoma.

Pancreatic ductal adenocarcinoma can be a difficult imaging diagnosis early in its course given its subtle imaging findings such as focal pancreatic duct dilatation, abrupt duct cut-off, and encasement of vasculature. A variety of pancreatitidies have imaging findings that mimic pancreatic ductal adenocarcinoma and lead to mass formation making diagnosis even more difficult on imaging alone. These conditions include acute focal pancreatitis, chronic pancreatitis, autoimmune pancreatitis, and paraduodenal ("groove") pancreatitis. This review will focus on imaging findings that can help differentiate these inflammatory processes from pancreatic ductal adenocarcinoma.

Ultrasound Assessment of Acute Kidney Injury.

Ultrasound assessment of the kidneys in patients with renal impairment has been described in various ways in the critical care, nephrology, and radiology literature, resulting in a somewhat heterogeneous picture of the gray-scale and Doppler ultrasound manifestation of acute kidney injury (AKI). Given that ultrasound assessment can potentially identify reversible causes of AKI or identify underlying chronic kidney disease, it is important for radiologists to be aware of the common etiologies of AKI and the spectrum of ultrasound findings. We review the definition and etiologies of renal injury and introduce the ultrasound SERVeillance framework-assessment of renal size, echogenicity, renal hilum, and vascularity-for the imaging assessment of AKI.