The Society of Abdominal Radiology at 10 years: Reflections, status report, and look to the future.

In 2012, the Society of Abdominal Radiology (SAR) was formed by the merger of the Society of Gastrointestinal Radiologists (SGR) and the Society of Uroradiology (SUR). On the occasion of SAR's ten year anniversary, this commentary describes important changes in society structure, the growth and diversity of society membership, new educational and research initiatives, intersociety and international outreach, and plans for the future.

Initial Experience with a COVID-19 Screening Chatbot Before Radiology Appointments.

Guidelines for COVID-19 issued by the Centers for Disease Control and Prevention prompted state and local governments to mandate safety measures for screening high-risk patient populations and for institutions to look for ways to limit human contact when possible. The aim of this study was to determine the feasibility of an automated communication system (chatbot) for COVID-19 screening before patients' radiology appointments and to describe patient experiences with the chatbot. We developed a chatbot for COVID-19 screening before outpatient radiology examination appointments and tested it in a pilot study from July 6 to August 31, 2020. The chatbot assessed the presence of any symptoms, exposure, and recent testing. User experience was assessed via a questionnaire based on a 5-point Likert scale. Multivariable logistic regression was performed to predict response rate. The chatbot COVID-19 screening SMS message was sent to 4687 patients. Of these patients, 2722 (58.1%) responded. Of the respondents, 46 (1.7%) reported COVID-19 symptoms; 34 (1.2%) had COVID-19 tests scheduled or pending. Of the 1965 nonresponders, authentication failed for 174 (8.8%), 1496 (76.1%) did not engage with the SMS message, and 251 (12.8%) timed out of the chatbot. The mean rating for the chatbot experience was 4.6. In a multivariable logistic regression model predicting response rate, English written-language preference independently predicted response (odds ratio, 2.71 [95% CI, 1.77-2.77]; P = .007). Age (P = 0.57) and sex (P = 0.51) did not predict response rate. SMS-based COVID-19 screening before scheduled radiology appointments was feasible. English written-language preference (not age or sex) was associated with higher response rate.

Enabling Your Radiology Business to Thrive Strategic Lessons Learned During the Initial and Subsequent Surges of the Covid-19 Pandemic.

The Covid-19 pandemic surges of 2020 resulted in major operational, personal, and financial impacts on US radiology practices. In response, a series of strategic and intentional operational changes were implemented, varying by practice size, structure and model. In reviewing the many business lessons that we learned during the pandemic, it became clear that for a business to be successful, a host of additional supportive factors are necessary. In addition to timely expense reductions, optimizing revenue capture and close monitoring and management of cash and reserves available for use, we also consider effective leadership and communication strategies, maintenance of a healthy and adequately staffed team, support for a remote work environment and flexible staffing models. Other ingredients include effectively embracing digital media for communications, careful attention to current and new stakeholders and the service delivered to them, understanding federal and state regulatory changes issued in response to the pandemic, close collaboration with the Human Resources office, and an early focus on redesigning your future practice structure and function, including disaster and downtime planning. This review aims to share lessons to enable leaders of an imaging enterprise to be better prepared for similar and future surges.

Mucin-Containing Rectal Carcinomas: Overview of Unique Clinical and Imaging Features.

OBJECTIVE. The purpose of this study is to review the unique clinical and imaging features of mucin-containing rectal carcinomas. CONCLUSION. Mucinous rectal carcinoma is an uncommon tumor subtype with a worse prognosis. At MRI, it is marked by T2-hyperintense extracellular mucin. Difficulty in distinguishing cellular from acellular mucin and persistent tumor bulk can cause errors at restaging. Signet ring cell carcinoma contains intracellular mucin. The classic imaging appearance is rectal linitis plastica. Both tumor subtypes have a unique metastatic pattern.

Using Naïve Bayesian Analysis to Determine Imaging Characteristics of KRAS Mutations in Metastatic Colon Cancer.

Genotype, particularly Ras status, greatly affects prognosis and treatment of liver metastasis in colon cancer patients. This pilot aimed to apply word frequency analysis and a naive Bayes classifier on radiology reports to extract distinguishing imaging descriptors of wild-type colon cancer patients and those with v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations. In this institutional-review-board-approved study, we compiled a SNaPshot mutation analysis dataset from 457 colon adenocarcinoma patients. From this cohort of patients, we analyzed radiology reports of 299 patients (> 32,000 reports) who either were wild-type (147 patients) or had a KRAS (152 patients) mutation. Our algorithm determined word frequency within the wild-type and mutant radiology reports and used a naive Bayes classifier to determine the probability of a given word belonging to either group. The classifier determined that words with a greater than 50% chance of being in the KRAS mutation group and which had the highest absolute probability difference compared to the wild-type group included: "several", "innumerable", "confluent", and "numerous" (p < 0.01). In contrast, words with a greater than 50% chance of being in the wild type group and with the highest absolute probability difference included: "few", "discrete", and "[no] recurrent" (p = 0.03). Words used in radiology reports, which have direct implications on disease course, tumor burden, and therapy, appear with differing frequency in patients with KRAS mutations versus wild-type colon adenocarcinoma. Moreover, likely characteristic imaging traits of mutant tumors make probabilistic word analysis useful in identifying unique characteristics and disease course, with applications ranging from radiology and pathology reports to clinical notes.

Molecular and Clinical Approach to Intra-abdominal Adverse Effects of Targeted Cancer Therapies.

Targeted cancer therapies encompass an exponentially growing number of agents that involve a myriad of molecular pathways. To excel within this rapidly changing field of clinical oncology, radiologists must eschew traditional organ system-based approaches of cataloging adverse effects in favor of a conceptual framework that incorporates molecular mechanisms and associated clinical outcomes. Understanding molecular mechanisms that underlie imaging manifestations of adverse effects and known associations with treatment response allows radiologists to more effectively recognize adverse effects and differentiate them from tumor progression. Radiologists can therefore more effectively guide oncologists in the management of adverse effects and treatment decisions regarding continuation or cessation of drug therapy. Adverse effects from targeted cancer therapies can be classified into four categories: (a) category 1, on-target adverse effects associated with treatment response; (b) category 2, on-target adverse effects without associated treatment response; (c) category 3, off-target adverse effects; and (d) category 4, tumor necrosis-related adverse effects. This review focuses on adverse effects primarily within the abdomen and pelvis classified according to established or hypothesized molecular mechanisms and illustrated with images of classic examples and several potential emerging toxic effects. ©RSNA, 2017.

ACR Appropriateness Criteria® Pretreatment Staging of Colorectal Cancer.

Colorectal cancers are common tumors in the United States and appropriate imaging is essential to direct appropriate care. Staging and treatment differs between tumors arising in the colon versus the rectum. Local staging for colon cancer is less integral to directing therapy given radical resection is often standard. Surgical options for rectal carcinoma are more varied and rely on accurate assessment of the sphincter, circumferential resection margins, and peritoneal reflection. These important anatomic landmarks are best appreciated on high-resolution imaging with transrectal ultrasound or MRI. When metastatic disease is suspected, imaging modalities that provide a global view of the body, such as CT with contrast or PET/CT may be indicated. Rectal cancer often metastasizes to the liver and so MRI of the liver with and without contrast provides accurate staging for liver metastases. This article focuses on local and distant staging and reviews the appropriateness of different imaging for both variants. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Review of paratesticular pathology: findings on ultrasound and MRI.

The paratesticular scrotal contents consist of the spermatic cord, epididymis, and fascia, which originate from the embryologic descent of the testis through the abdominal wall. Historically, the primary diagnostic modality has been high-resolution ultrasound. Magnetic resonance imaging (MRI) is an alternative imaging option. Both contrast MRI and diffusion weighted imaging can assist in differentiating between benign and malignant lesions. Unlike the testis which most disease processes are malignant, a wide spectrum of benign disease processes affects the paratesticular region either in isolation or as part of a contiguous disease process from adjacent organs. The familiarity with the epidemiology, pathogenesis, and imaging features can aid the radiologic diagnoses and guide appropriate clinical management. In this article, we review the ultrasound and MR characteristics of various paratesticular pathologies.

Malignancy after Solid Organ Transplantation: Comprehensive Imaging Review.

Life expectancies for solid organ recipients as well as graft survival rates for these patients have improved over the years because of advanced immunosuppressive therapies; however, with chronic use of these drugs, posttransplant malignancy has become one of the leading causes of morbidity for them. The risk of carcinogenesis in transplant recipients is significantly higher than for the general population and cancers tend to manifest at an advanced stage. Posttransplant malignancies are thought to develop by three mechanisms: de novo development, donor-related transmission, and recurrence of a recipient's pretransplant malignancy. Although nonmelanoma skin cancer, Kaposi sarcoma, posttransplant lymphoproliferative disorder, anogenital cancer, and lung cancer are malignancies that are thought to arise de novo, malignant melanoma and cancers that arise in the renal allograft are frequently donor related. Hepatocellular carcinomas and cholangiocarcinomas have a greater tendency to recur in liver transplant recipients. An altered or deranged immune system caused by chronic immunosuppression is considered to be one of the major contributing factors to carcinogenesis. The proposed pathogenic mechanisms for oncogenesis include impaired immunosurveillance of neoplastic cells, weakened immune activity against oncogenic viruses, and direct carcinogenic effects of immunosuppressive agents. Imaging plays an important role in screening, follow-up, and long-term surveillance in patients with malignancies because key imaging features can guide in their timely diagnosis. However, some benign entities such as transplant-related renal fibrosis, biliary necrosis, and infectious nodules in the lungs mimic malignancies and require pathologic confirmation. Management strategies that can improve malignancy-related morbidity and mortality in transplant recipients include prevention of risk factors, appropriate modulation of immunosuppressive agents, prophylaxis against infection-related malignancies, and use of intensive targeted screening programs. (©)RSNA, 2016.

Tumors and Tumorlike Conditions of the Anal Canal and Perianal Region: MR Imaging Findings.

Tumors and tumorlike conditions of the anus and perianal region originate from the anal canal and anal margin or result from direct extension of tumors from adjacent organs. The anatomy of the anal canal is complex, and its different histologic characteristics can lead to diverse pathologic conditions. The anal canal extends from the anorectal junction to the anal verge. The World Health Organization classification of anal canal tumors includes (a) anal intraepithelial neoplasia, the precursor of squamous cell carcinoma (SCC), and (b) invasive tumors. Invasive tumors are further classified on the basis of cell type as epithelial tumors (SCC, adenocarcinoma, mucinous adenocarcinoma, small cell carcinoma, and undifferentiated carcinoma), nonepithelial tumors, carcinoid tumors, melanoma, and secondary tumors (direct spread from rectal, cervical, or prostate carcinoma). The anal margin, or perianal skin, lies outside the anal verge and encompasses a radius of 5 cm from the anal verge. Tumors in the anal margin are classified according to the World Health Organization classification of skin tumors. Anal margin tumors include SCC, anal intraepithelial neoplasia, also known as Bowen disease, adenocarcinoma and its precursor Paget disease, basal cell carcinoma, and verrucous carcinoma (Buschke-Löwenstein tumor), which is a rare variant of SCC. Imaging plays an important role in the evaluation, staging, and follow-up of patients with anal and perianal tumors. However, because of the overlap in imaging features among these diverse entities, a definitive diagnosis is best established at histopathologic examination. Nevertheless, familiarity with the pathogenesis, imaging features, and treatment of these tumors can aid radiologic diagnosis and guide appropriate patient treatment. (©)RSNA, 2016.

Imaging of Drug-induced Complications in the Gastrointestinal System.

Drug-induced injury commonly affects the gastrointestinal and hepatobiliary systems because of the mechanisms of absorption and metabolism. In pill esophagitis, injury is frequently related to direct contact with the esophageal mucosa, resulting in small superficial ulcers in the mid esophagus. Nonsteroidal anti-inflammatory drugs can lead to gastrointestinal tract ulcers and small bowel mucosal diaphragms (thin weblike strictures). Injury to the pancreatic and hepatobiliary systems can manifest as pancreatitis, acute or chronic hepatitis, cholestasis, or steatosis and steatohepatitis (which may progress to cirrhosis). Various drugs may also insult the hepatic vasculature, resulting in Budd-Chiari and sinusoidal obstructive syndromes. Focal lesions such as hepatic adenomas may develop after use of oral contraceptives or anabolic steroids. Ultrasonography, computed tomography, and magnetic resonance imaging can aid in diagnosis of drug-induced injuries and often are necessary to exclude other causes.

Adaptive noise correction of dual-energy computed tomography images.

PURPOSE: Noise reduction in material density images is a necessary preprocessing step for the correct interpretation of dual-energy computed tomography (DECT) images. In this paper we describe a new method based on a local adaptive processing to reduce noise in DECT images METHODS: An adaptive neighborhood Wiener (ANW) filter was implemented and customized to use local characteristics of material density images. The ANW filter employs a three-level wavelet approach, combined with the application of an anisotropic diffusion filter. Material density images and virtual monochromatic images are noise corrected with two resulting noise maps. RESULTS: The algorithm was applied and quantitatively evaluated in a set of 36 images. From that set of images, three are shown here, and nine more are shown in the online supplementary material. Processed images had higher signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) than the raw material density images. The average improvements in SNR and CNR for the material density images were 56.5 and 54.75%, respectively. CONCLUSION: We developed a new DECT noise reduction algorithm. We demonstrate throughout a series of quantitative analyses that the algorithm improves the quality of material density images and virtual monochromatic images.

MR Imaging of the Penis and Scrotum.

Traditionally, due to its low cost, ready availability, and proved diagnostic accuracy, ultrasonography (US) has been the primary imaging modality for the evaluation of scrotal and, to a lesser extent, penile disease. However, US is limited by its relatively small useful field of view, operator dependence, and inability to provide much information on tissue characterization. Magnetic resonance (MR) imaging, with its excellent soft-tissue contrast and good spatial resolution, is increasingly being used as both a problem-solving tool in patients who have already undergone US and as a primary modality for the evaluation of suspected disease. Specifically, MR imaging can aid in differentiating between benign and malignant lesions seen at US, help define the extent of inflammatory processes or traumatic injuries, and play a vital role in locoregional staging of tumors. Consequently, it is becoming more important for radiologists to be familiar with the wide range of penile and scrotal disease entities and their MR imaging appearances. The authors review the basic anatomy of the penis and scrotum as seen at MR imaging and provide a basic protocol for penile and scrotal imaging, with emphasis on the advantages of MR imaging. Pathologic processes are organized into traumatic (including penile fracture and contusion), infectious or inflammatory (including Fournier gangrene and scrotal abscess), and neoplastic (including both benign and malignant scrotal and penile tumors) processes.

Selection and pilot implementation of a mobile image viewer: a case study.

BACKGROUND: For health care providers, mobile image viewing increases image accessibility, which could lead to faster interpretation/consultations and improved patient outcomes. OBJECTIVE: We explored the technical requirements and challenges associated with implementing a commercial mobile image viewer and conducted a small study testing the hypothesis that the mobile image viewer would provide faster image access. METHODS: A total of 19 clinicians (9 radiologists, 3 surgeons, 4 neurologists, and 3 physician assistants) evaluated (1) a desktop commercial picture archiving and communication system (PACS) viewer, (2) a desktop viewer developed internally over 20 years and deployed throughout the enterprise (ENTERPRISE viewer) and (3) a commercial Food and Drug Administration class II-cleared mobile viewer compatible with Web browsers, tablets, and mobile phones. Data were collected during two separate 7-day periods, before and after mobile image viewer deployment. Data included image viewer chosen, time to view first image, technical issues, diagnostic confidence, and ease of use. RESULTS: For 565 image-viewing events, ease of use was identical for PACS and mobile viewers (mean 3.6 for all scores of a possible 4.0), and significantly worse for the enterprise viewer (mean 2.9, P=.001). Technical issues were highest with the enterprise viewer (26%, 56/215) compared with the mobile (7%,19/259, P=.001) and PACS (8%, 7/91, P=.003) viewers. Mean time to first image for the mobile viewer (2.4 minutes) was significantly faster than PACS (12.5 minutes, P=.001) and the enterprise viewer (4.5 minutes, P=.001). Diagnostic confidence was similar for PACS and mobile viewers and worst for enterprise viewer. Mobile image viewing increased by sixfold, from 14% (37/269, before the deployment) to 88.9% (263/296, after the deployment). CONCLUSIONS: A mobile viewer provided faster time to first image, improved technical performance, ease of use, and diagnostic confidence, compared with desktop image viewers.

Observer Performance in the Detection and Classification of Malignant Hepatic Nodules and Masses with CT Image-Space Denoising and Iterative Reconstruction.

PURPOSE: To determine if lower-dose computed tomographic (CT) scans obtained with adaptive image-based noise reduction (adaptive nonlocal means [ANLM]) or iterative reconstruction (sinogram-affirmed iterative reconstruction [SAFIRE]) result in reduced observer performance in the detection of malignant hepatic nodules and masses compared with routine-dose scans obtained with filtered back projection (FBP). MATERIALS AND METHODS: This study was approved by the institutional review board and was compliant with HIPAA. Informed consent was obtained from patients for the retrospective use of medical records for research purposes. CT projection data from 33 abdominal and 27 liver or pancreas CT examinations were collected (median volume CT dose index, 13.8 and 24.0 mGy, respectively). Hepatic malignancy was defined by progression or regression or with histopathologic findings. Lower-dose data were created by using a validated noise insertion method (10.4 mGy for abdominal CT and 14.6 mGy for liver or pancreas CT) and images reconstructed with FBP, ANLM, and SAFIRE. Four readers evaluated routine-dose FBP images and all lower-dose images, circumscribing liver lesions and selecting diagnosis. The jackknife free-response receiver operating characteristic figure of merit (FOM) was calculated on a per-malignant nodule or per-mass basis. Noninferiority was defined by the lower limit of the 95% confidence interval (CI) of the difference between lower-dose and routine-dose FOMs being less than -0.10. RESULTS: Twenty-nine patients had 62 malignant hepatic nodules and masses. Estimated FOM differences between lower-dose FBP and lower-dose ANLM versus routine-dose FBP were noninferior (difference: -0.041 [95% CI: -0.090, 0.009] and -0.003 [95% CI: -0.052, 0.047], respectively). In patients with dedicated liver scans, lower-dose ANLM images were noninferior (difference: +0.015 [95% CI: -0.077, 0.106]), whereas lower-dose FBP images were not (difference -0.049 [95% CI: -0.140, 0.043]). In 37 patients with SAFIRE reconstructions, the three lower-dose alternatives were found to be noninferior to the routine-dose FBP. CONCLUSION: At moderate levels of dose reduction, lower-dose FBP images without ANLM or SAFIRE were noninferior to routine-dose images for abdominal CT but not for liver or pancreas CT.

Observer performance for adaptive, image-based denoising and filtered back projection compared to scanner-based iterative reconstruction for lower dose CT enterography.

PURPOSE: The purpose of this study was to compare observer performance for detection of intestinal inflammation for low-dose CT enterography (LD-CTE) using scanner-based iterative reconstruction (IR) vs. vendor-independent, adaptive image-based noise reduction (ANLM) or filtered back projection (FBP). METHODS: Sixty-two LD-CTE exams were performed. LD-CTE images were reconstructed using IR, ANLM, and FBP. Three readers, blinded to image type, marked intestinal inflammation directly on patient images using a specialized workstation over three sessions, interpreting one image type/patient/session. Reference standard was created by a gastroenterologist and radiologist, who reviewed all available data including dismissal Gastroenterology records, and who marked all inflamed bowel segments on the same workstation. Reader and reference localizations were then compared. Non-inferiority was tested using Jackknife free-response ROC (JAFROC) figures of merit (FOM) for ANLM and FBP compared to IR. Patient-level analyses for the presence or absence of inflammation were also conducted. RESULTS: There were 46 inflamed bowel segments in 24/62 patients (CTDIvol interquartile range 6.9-10.1 mGy). JAFROC FOM for ANLM and FBP were 0.84 (95% CI 0.75-0.92) and 0.84 (95% CI 0.75-0.92), and were statistically non-inferior to IR (FOM 0.84; 95% CI 0.76-0.93). Patient-level pooled confidence intervals for sensitivity widely overlapped, as did specificities. Image quality was rated as better with IR and AMLM compared to FBP (p < 0.0001), with no difference in reading times (p = 0.89). CONCLUSIONS: Vendor-independent adaptive image-based noise reduction and FBP provided observer performance that was non-inferior to scanner-based IR methods. Adaptive image-based noise reduction maintained or improved upon image quality ratings compared to FBP when performing CTE at lower dose levels.

Polypoid lesions of the gallbladder: disease spectrum with pathologic correlation.

Gallbladder polyps are seen on as many as 7% of gallbladder ultrasonographic images. The differential diagnosis for a polypoid gallbladder mass is wide and includes pseudotumors, as well as benign and malignant tumors. Tumefactive sludge may be mistaken for a gallbladder polyp. Pseudotumors include cholesterol polyps, adenomyomatosis, and inflammatory polyps, and they occur in that order of frequency. The most common benign and malignant tumors are adenomas and primary adenocarcinoma, respectively. Polyp size, shape, and other ancillary imaging findings, such as a wide base, wall thickening, and coexistent gallstones, are pertinent items to report when gallbladder polyps are discovered. These findings, as well as patient age and risk factors for gallbladder cancer, guide clinical decision making. Symptomatic polyps without other cause for symptoms, an age over 50 years, and the presence of gallstones are generally considered indications for cholecystectomy. Incidentally noted pedunculated polyps smaller than 5 mm generally do not require follow-up. Polyps that are 6-10 mm require follow-up, although neither the frequency nor the length of follow-up has been established. Polyps that are larger than 10 mm are typically excised, although lower size thresholds for cholecystectomy may be considered for patients with increased risk for gallbladder carcinoma, such as patients with primary sclerosing cholangitis.