Updates on LI-RADS Treatment Response Criteria for Hepatocellular Carcinoma: Focusing on MRI.

As the incidence of hepatocellular carcinoma (HCC) and subsequent treatments with liver-directed therapies rise, the complexity of assessing lesion response has also increased. The Liver Imaging Reporting and Data Systems (LI-RADS) treatment response algorithm (LI-RADS TRA) was created to standardize the assessment of response after locoregional therapy (LRT) on contrast-enhanced CT or MRI. Originally created based on expert opinion, these guidelines are currently undergoing revision based on emerging evidence. While many studies support the use of LR-TRA for evaluation of HCC response after thermal ablation and intra-arterial embolic therapy, data suggest a need for refinements to improve assessment after radiation therapy. In this manuscript, we review expected MR imaging findings after different forms of LRT, clarify how to apply the current LI-RADS TRA by type of LRT, explore emerging literature on LI-RADS TRA, and highlight future updates to the algorithm. EVIDENCE LEVEL: 3. TECHNICAL EFFICACY: Stage 2.

A Natural Language Processing and Machine Learning Approach to Identification of Incidental Radiology Findings in Trauma Patients Discharged from the Emergency Department.

STUDY OBJECTIVE: Patients undergoing diagnostic imaging studies in the emergency department (ED) commonly have incidental findings, which may represent unrecognized serious medical conditions, including cancer. Recognition of incidental findings frequently relies on manual review of textual radiology reports and can be overlooked in a busy clinical environment. Our study aimed to develop and validate a supervised machine learning model using natural language processing to automate the recognition of incidental findings in radiology reports of patients discharged from the ED. METHODS: We performed a retrospective analysis of computed tomography (CT) reports from trauma patients discharged home across an integrated health system in 2019. Two independent annotators manually labeled CT reports for the presence of an incidental finding as a reference standard. We used regular expressions to derive and validate a random forest model using open-source and machine learning software. Final model performance was assessed across different ED types. RESULTS: The study CT reports were divided into derivation (690 reports) and validation (282 reports) sets, with a prevalence of incidental findings of 22.3%, and 22.7%, respectively. The random forest model had an area under the curve of 0.88 (95% confidence interval [CI], 0.84 to 0.92) on the derivation set and 0.92 (95% CI, 0.88 to 0.96) on the validation set. The final model was found to have a sensitivity of 92.2%, a specificity of 79.4%, and a negative predictive value of 97.2%. Similarly, strong model performance was found when stratified to a dedicated trauma center, high-volume, and low-volume community EDs. CONCLUSION: Machine learning and natural language processing can classify incidental findings in CT reports of ED patients with high sensitivity and high negative predictive value across a broad range of ED settings. These findings suggest the utility of natural language processing in automating the review of free-text reports to identify incidental findings and may facilitate interventions to improve timely follow-up.

Radiology Dictation Errors with COVID-19 Protective Equipment: Does Wearing a Surgical Mask Increase the Dictation Error Rate?

Our aim was to determine the effect of wearing a surgical mask on the number and type of dictation errors in unedited radiology reports. IRB review was waived for this prospective matched-pairs study in which no patient data was used. Model radiology reports (n = 40) simulated those typical for an academic medical center. Six randomized radiologists dictated using speech-recognition software with and without a surgical mask. Dictations were compared to model reports and errors were classified according to type and severity. A statistical model was used to demonstrate that error rates for all types of errors were greater when masks are worn compared to when they are not (unmasked: 21.7 ± 4.9 errors per 1000 words, masked: 27.1 ± 2.2 errors per 1000 words; adjusted p < 0.0001). A sensitivity analysis was performed, excluding a reader with a large number of errors. The sensitivity analysis found a similar difference in error rates for all types of errors, although significance was attenuated (unmasked: 16.9 ± 1.9 errors per 1000 words, masked: 20.1 ± 2.2 errors per 1000 words; adjusted p = 0.054). We conclude that wearing a mask results in a near-significant increase in the rate of dictation errors in unedited radiology reports created with speech-recognition, although this difference may be accentuated in some groups of radiologists. Additionally, we find that most errors are minor single incorrect words and are unlikely to result in a medically relevant misunderstanding.

The LI-RADS Version 2018 MRI Treatment Response Algorithm: Evaluation of Ablated Hepatocellular Carcinoma.

Background The Liver Imaging Reporting and Data System (LI-RADS) treatment response algorithm (TRA) is used to assess presumed hepatocellular carcinoma (HCC) after local-regional therapy, but its performance has not been extensively assessed. Purpose To assess the performance of LI-RADS version 2018 TRA in the evaluation of HCC after ablation. Materials and Methods In this retrospective study, patients who underwent ablation therapy for presumed HCC followed by liver transplantation between January 2011 and December 2015 at a single tertiary care center were identified. Lesions were categorized as completely (100%) or incompletely (≤99%) necrotic based on transplant histology. Three radiologists assessed pre- and posttreatment MRI findings using LI-RADS version 2018 and the TRA, respectively. Interreader agreement was assessed by using the Fleiss κ test. Performance characteristics for predicting necrosis category based on LI-RADS treatment response (LR-TR) category (viable or nonviable) were calculated by using generalized mixed-effects models to account for clustering by subject. Results A total of 36 patients (mean age, 58 years ± 5 [standard deviation]; 32 men) with 53 lesions was included. Interreader agreement for pretreatment LI-RADS category was 0.40 (95% confidence interval [CI]: 0.15, 0.67; P < .01) and was lower than the interreader agreement for TRA category (κ = 0.71; 95% CI: 0.59, 0.84; P < .01). After accounting for clustering by subject, sensitivity of tumor necrosis across readers ranged from 40% to 77%, and specificity ranged from 85% to 97% when LR-TR equivocal assessments were treated as nonviable. When LR-TR equivocal assessments were treated as viable, sensitivity of tumor necrosis across readers ranged from 81% to 87%, and specificity ranged from 81% to 85% across readers. Six (11%) of 53 treated lesions were LR-TR equivocal by consensus, with most (five of six) incompletely necrotic at histopathology. Conclusion The Liver Imaging Reporting and Data System treatment response algorithm can be used to predict viable or nonviable hepatocellular carcinoma after ablation. Most ablated lesions rated as treatment response equivocal were incompletely necrotic at histopathology. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Do and Mendiratta-Lala in this issue.

MRI of acute appendicitis.

Appendicitis is the most common cause of acute abdominal pain resulting in surgery. While historically ultrasound (US) and computed tomography (CT) have been used to evaluate for appendicitis and its related complications, magnetic resonance imaging (MRI) has become a highly accurate and increasingly utilized modality in the last two decades, particularly in the pediatric and pregnant patient populations in whom ionizing radiation is used reluctantly. This article discusses the advantages and disadvantages of MRI as a modality to evaluate for acute appendicitis, summarizes studies of the diagnostic performance relative to CT and US, provides a standard MR protocol, and describes MRI findings typical of acute appendicitis, common complications, and other differential diagnoses. Level of Evidence: 2 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;50:1367-1376.

MRI in pregnancy: Indications and practical considerations.

There is a constantly evolving knowledgebase regarding the safety of MRI in pregnant patients, as well as the safety of gadolinium administration, given potential fetal risks. This review provides an overview of national and international recommendations for patient screening and safety by trimester, evaluates the most recent literature regarding administration of gadolinium in pregnant patients, and discusses technical requirements when imaging pregnant patients. A protocol for imaging pregnant patients is provided, and multiple common indications for MRI in pregnancy are discussed. Level of Evidence 5. Technical Efficacy Stage 5. J. Magn. Reson. Imaging 2019;49:621-631.

Intravenous Corticosteroid Premedication Administered 5 Hours before CT Compared with a Traditional 13-Hour Oral Regimen.

Purpose To determine if the allergic-like breakthrough reaction rate of intravenous corticosteroid prophylaxis administered 5 hours before contrast material-enhanced computed tomography (CT) is noninferior to that of a traditional 13-hour oral regimen. Materials and Methods Institutional review board approval was obtained and informed consent waived for this retrospective noninferiority cohort study. Subjects (n = 202) who completed an accelerated 5-hour intravenous corticosteroid premedication regimen before low-osmolality contrast-enhanced CT for a prior allergic-like or unknown-type reaction to iodine-based contrast material from June 1, 2008, to June 30, 2016, were identified. The breakthrough reaction rate was compared by using the Farrington and Manning noninferiority likelihood score to test subjects premedicated with a traditional 13-hour oral regimen (2.1% [13 of 626]). All subjects were premedicated for a prior allergic-like or unknown-type reaction to iodine-based contrast material. A noninferiority margin of 4.0% was selected to allow for no more than a clinically negligible 6.0% breakthrough reaction rate in the cohort that received 5-hour intravenous corticosteroid prophylaxis. Results The breakthrough reaction rate for 5-hour intravenous prophylaxis was 2.5% (five of 202 patients; 95% confidence interval: 0.8%, 5.7%), which was noninferior to the 2.1% (13 of 626 patients; 95% confidence interval: 1.1%, 3.5%) rate for the 13-hour regimen (P = .0181). The upper limits of the confidence interval for the difference between the two rates was 3.7% (0.4%; 95% confidence interval: -1.6%, 3.7%), which was within the 4.0% noninferiority margin. All breakthrough reactions were of equal or lesser severity to those of the index reactions (two severe, one moderate, and one mild reaction). Conclusion Accelerated intravenous premedication with corticosteroids beginning 5 hours before contrast-enhanced CT has a breakthrough reaction rate noninferior to that of a 13-hour oral premedication regimen. © RSNA, 2017.

Indirect Cost and Harm Attributable to Oral 13-Hour Inpatient Corticosteroid Prophylaxis before Contrast-enhanced CT.

PURPOSE: To estimate the effect of an oral 13-hour inpatient corticosteroid premedication regimen on length of stay, hospital cost, and hospital-acquired infections (HAIs) by using a combination of real and hypothetical study populations. MATERIALS AND METHODS: Institutional review board approval was obtained and informed consent waived for this HIPAA-compliant retrospective study. Inpatients who received an oral 13-hour corticosteroid premedication regimen before contrast material-enhanced CT (n = 1424) from 2008 to 2013 were matched by age, sex, and year when CT was performed to a control cohort (n = 1425) of patients who underwent contrast-enhanced CT without premedication and who had similar rates of 13 comorbid diseases. Length of stay in the hospital and time from admission to CT were compared by using the Mann-Whitney U test. Rates of prospectively reported HAIs were compared by using χ(2) tests. The indirect cost and risk of HAI with premedication were estimated by using published data. RESULTS: Premedicated inpatients had a significantly longer median length of stay (+25 hours; 158 vs 133 hours, P < .001), a significantly longer median time to CT (+25 hours, 42 vs 17 hours, respectively; P < .001), and a significantly greater risk of HAI (5.1% [72 of 1424] vs 3.1% [44 of 1424], respectively; P = .008) compared with nonpremedicated control subjects. On the basis of these data and existing references, the prolonged length of stay was estimated to result in 0.04 HAI-related deaths and a cost of $159 131 (in U.S. dollars) for each prevented reaction of any severity and 32 HAI-related deaths and a cost of $131 211 400 for each prevented reaction-related death. CONCLUSION: Oral 13-hour inpatient corticosteroid prophylaxis is associated with substantial cost relative to its modest benefit, and may cause more indirect harm than the direct harm that it prevents.

Rates of Breakthrough Reactions in Inpatients at High Risk Receiving Premedication Before Contrast-Enhanced CT.

OBJECTIVE: The purpose of this study was to determine the rate of allergiclike breakthrough reactions among inpatients at high risk receiving premedication before undergoing CT with IV iodinated low-osmolality contrast material (LOCM). MATERIALS AND METHODS: Inpatients (n = 1051) completing a 13-hour corticosteroid and diphenhydramine premedication regimen before LOCM-enhanced CT from January 1, 2010, through December 31, 2013, were included in the study. Breakthrough reaction rates were compared with the ordinary allergiclike reaction rate in the general population (0.6% [545/84,928]) by use of chi-square tests. Multivariate logistic regression was performed. Number needed to treat (NNT) was calculated for patients premedicated for a previous contrast reaction. RESULTS: Sixty percent (626/1051) of premedicated patients had had a previous reaction to iodinated contrast material, and 40% (425/1051) were premedicated for other reasons. The overall breakthrough reaction rates were 1.2% (13/1051) (p < 0.0001 vs the general population), 2.1% (13/626) for those with a previous iodinated contrast reaction (p < 0.0001), and 0% (0/425) for those premedicated for other reasons (p = 0.18). There were no severe breakthrough reactions. Younger age (p = 0.046; odds ratio, 1.03 per year; 95% CI, 1.001-1.07) and multiple indications for premedication (p < 0.0001; odds ratio, 2.7 per indication; 95% CI, 1.5-4.8) significantly increased the likelihood of a breakthrough reaction. The estimated NNTs were 69 (95% CI, 39-304) to prevent a reaction of any severity and 569 (95% CI, 389-1083) to prevent a severe reaction. CONCLUSION: Patients premedicated for a previous reaction to iodinated contrast material have a breakthrough reaction rate 3-4 times the ordinary reaction rate in the general population. Patients receiving premedication for other reasons have a breakthrough reaction rate near 0%. Many patients must receive premedication to prevent one reaction.

Pancreatic Transplantation: Surgical Anatomy and Complications.

Pancreatic transplantation is a complex surgical procedure performed for patients with chronic severe diabetes, often performed in combination with renal transplantation. Vascular and exocrine drainage anatomy varies depending on the surgical technique. Radiology plays a critical role in the diagnosis of postoperative complications, requiring an understanding of grayscale/Doppler ultrasound as well as computed tomography and MR imaging. In this review, we detail usual surgical methods and normal postoperative imaging appearances. We then review the most common complications following pancreatic transplants, emphasizing diagnostic features of vascular (arterial/venous), surgical, and diffuse parenchymal pathologic conditions on multiple imaging modalities.

A Review of the Clinical Applications of Artificial Intelligence in Abdominal Imaging.

Artificial intelligence (AI) has been a topic of substantial interest for radiologists in recent years. Although many of the first clinical applications were in the neuro, cardiothoracic, and breast imaging subspecialties, the number of investigated and real-world applications of body imaging has been increasing, with more than 30 FDA-approved algorithms now available for applications in the abdomen and pelvis. In this manuscript, we explore some of the fundamentals of artificial intelligence and machine learning, review major functions that AI algorithms may perform, introduce current and potential future applications of AI in abdominal imaging, provide a basic understanding of the pathways by which AI algorithms can receive FDA approval, and explore some of the challenges with the implementation of AI in clinical practice.

A low mortality model of chronic pulmonary hypertension in sheep.

BACKGROUND: Pulmonary hypertension and right ventricular failure are major contributors to morbidity and mortality in chronic lung disease. Therefore, large animal models of pulmonary hypertension and right ventricular hypertrophy are needed to study underlying disease mechanisms and test new treatment modalities. The objective of this study was to create a low-mortality model of chronic pulmonary hypertension and right ventricular hypertrophy in sheep. METHODS: The vena cavae of nine sheep weighing 62 ± 2 (SEM) kg were injected with 0.375 g of dextran beads (sephadex) every day for 60 d. Pulmonary hemodynamics were assessed via pulmonary artery catheterization prior to the first injection and again on d 14, 28, 35, 42, 49, and 56. At the end of the experiment, the heart was removed, dissected, and weighed to determine the ratio of right ventricular mass to left ventricle plus septal mass (RV:LV+S). RESULTS: All sheep survived to 60 d. The average pulmonary artery pressure rose from 17 ± 1 mmHg at baseline to 35 ± 3 mmHg on d 56 with no significant change in cardiac output (8.7 ± 0.7 to 9.8 ± 0.7 L/min, P = 0.89). The RV:LV+S was significantly higher (0.42 ± 0.01, P < 0.001) than a historic group of untreated normal animals (0.35 ± 0.01, n = 13). CONCLUSION: This study provides a low-mortality large animal model of moderate chronic pulmonary hypertension and right ventricular hypertrophy.

Paralabral cysts of the hip: sonographic evaluation with magnetic resonance arthrographic correlation.

This retrospective study demonstrates the sonographic appearance paralabral cysts of the hip with magnetic resonance (MR) arthrography as the reference standard. Consensus review by 2 musculoskeletal radiologists was used to assess the paralabral cysts and determine their characteristics. The 3 paralabral cysts seen on sonography and confirmed with MR arthrography in this study were anechoic or hypoechoic, lobulated, and filled with contrast on MR imaging. A labral tear was also noted in all cases on both sonography and MR arthrography. Sonographic assessment for an anterior hip paralabral cyst and labral tear may be of diagnostic benefit.

Understanding differences in practices and preferences during videofluoroscopic swallow studies: A survey of radiologists and speech language pathologists in the United States.

PURPOSE: The purpose of this study was to (a) examine the interprofessional relationship between radiologists and speech-language pathologists (SLPs), and (b) explore viewpoints and practice patterns of each profession regarding a videofluoroscopic swallow study (VFSS). METHODS: This IRB approved study utilized an online survey developed by the authors to gather information from radiologists and SLPs who currently perform videofluoroscopic swallow studies (VFSS) for the evaluation of swallow function. Surveys were primarily distributed through the American Speech-Language-Hearing Association's (ASHA) Special Interest Group 13 (Swallowing and Swallowing Disorders) forum, through LinkedIn and email networking among professional radiology-focused businesses and organizations (Bracco Diagnostics, Inc., Society of Abdominal Radiology), and via social media (e.g. Facebook). The survey consisted of 7 demographic questions and 15 practice-related items, using a modified Likert scale and multiple-choice items to assess agreement with statements regarding VFSS procedures and opinions on professional roles. RESULTS: Radiologists and SLPs differed significantly (p < 0.05) in practices regarding nearly all items surveyed, including preferences on: esophageal sweep, anteroposterior view, fluoroscopy time limitation, termination following an aspiration event, frame rate, as well as in defining the primary role of the SLP, the primary purpose of a VFSS, the most valuable piece of information obtained from a VFSS, and training requirements. Radiologists and SLPs agreed that a standardized protocol should exist for VFSS. CONCLUSIONS: Radiologists and SLPs differ in their practice patterns and opinions on the roles of team members in the performance of VFSS. However, both radiologists and SLPs agree that a standardized protocol for VFSS should exist.

Metastatic basal cell carcinoma with atypical pattern of spread.

Basal cell carcinoma is the most common malignancy in the United States. However, metastasis of basal cell carcinoma is exceedingly rare, with incidence estimates of 0.0028-0.055%. When it does metastasize, basal cell carcinoma most commonly spreads to regional lymph nodes and lungs, although other sites of disease can occur. This case report presents multi-modality imaging of a 54-year-old male who developed multifocal metastatic basal cell carcinoma approximately three years after initial presentation with an ulcerated groin lesion. Ultimately, metastases included many common and uncommon sites, including lymph nodes, lung, duodenum, spleen, and adrenal glands. This case provides an interesting example of an uncommon pattern of spread and associated symptoms of treatment-resistant metastatic basal cell carcinoma.

Breakthrough Reactions to Gadobenate Dimeglumine.

PURPOSE: The aim of this study was to determine the severity of breakthrough reactions to gadobenate dimeglumine in patients premedicated with a 13-hour premedication regimen. METHODS: Institutional review board approval was obtained and informed consent waived for this Health Insurance Portability and Accountability Act-compliant retrospective cohort study. All acute allergic-like reactions to gadobenate dimeglumine from 11/1/2008 to 1/31/2016 were identified. Of these, 19 allergic-like reactions followed 13-hour premedication: 150 mg prednisone and 50 mg diphenhydramine (ie, "breakthrough reactions"). Reasons for premedication, risk factors, index reaction characteristics, and breakthrough reaction characteristics were catalogued. Reaction severities were assigned using American College of Radiology guidelines. Severities of breakthrough (n = 19) and nonbreakthrough reactions (n = 97) were compared with the Cochran-Armitage test for trend. RESULTS: Premedication was most commonly given (63% [12/19]) for a previous allergic-like reaction to gadolinium-based contrast material (GBCM); in 37% (7/19), it was given for a different risk factor. In those premedicated for a previous allergic-like reaction to GBCM of known severity (n = 9), the breakthrough reaction severity was the same as index reaction severity in 56% (5/9), less severe in 11% (1/9), and of greater severity in 33% (3/9). Two severe breakthrough reactions occurred; both were in subjects premedicated for risk factors other than a previous GBCM reaction. No subjects died. Five subjects were reexposed to GBCM a total of 9 times; no repeat breakthrough reactions occurred. Breakthrough reactions were more severe than nonbreakthrough reactions (P = 0.046), but the level of significance was borderline. CONCLUSION: Premedication does not eliminate severe reactions to gadobenate dimeglumine. Breakthrough reactions to gadobenate dimeglumine can be of greater severity than index reactions.