"My attending really wants it!" Manual clinical decision support adjudicating the "better look" inpatient MRI at an academic medical center.

OBJECTIVE: MRI utilization in the United States is relatively higher than in other parts of the world and inpatient MRI utilization is particularly difficult to manage given the lack of direct reimbursement. Body MRI studies present an opportunity to reduce inpatient MRI utilization since they are generally the least emergent. Our objective was to use a targeted questionnaire to probe the necessity of inpatient body MRI orders and present an opportunity to either cancel them or transition them to the outpatient realm METHODS: A 9-item questionnaire was devised asking questions about the urgency of the inpatient MRI order including the urgent management question, an inpatient procedure or whether it was recommended by a consultant. Peer-to-peer discussion walking through each of the questions was conducted by radiology housestaff with the ordering clinicians and responses recorded. RESULTS: 845 recorded responses reported a lack of specific clinical question in 23.9% of orders, 68.9% were recommended by a non-radiology consulting service and 16.1% were recommended by radiology studies. 17.0% orders were felt to be outpatient appropriate and 23.3% were considered possibly appropriate for the outpatient setting. 3.9% were canceled and 4.9% were transitioned to outpatient orders. DISCUSSION: Engaging in a focused discussion about the urgency and appropriateness of an inpatient MRI body order following a list of scripted questions has the potential to reduce utilization. This approach also highlights the relatively high rate of indication uncertainty among ordering clinicians and the central role of consultants in prompting orders.

Pancreatic Walled-Off Necrosis: Cross-Sectional Imaging Depiction of Debris Predicts the Success of Endoscopic Drainage Using Lumen Apposing Metal Stents.

BACKGROUND: The use of endoscopic ultrasound-guided (EUS) transmural stent placement for pancreatic walled-off-necrosis (WON) drainage is widespread. This study retrospectively analyzes imaging parameters predicting the outcomes of WON endoscopic drainage using lumen apposing metal stents (LAMS). METHODS: The study analyzed data of 115 patients who underwent EUS-guided debridement using LAMS from 2011 to 2015. Pre-intervention CT or MRI were used to analyze WON total volume, percentage of debris, multilocularity, and density. Success measures included technical success, the number of endoscopic sessions, requirement of percutaneous drainage, long-term success, and recurrence. RESULTS: The primary cause of pancreatitis was gallstones (50.4%), followed by alcohol (27.8%), hypertriglyceridemia (11.3%), idiopathic (8.7%), and autoimmune (1.7%). The mean WON size was 674 mL. All patients underwent endoscopic necrosectomies, averaging 3.1 sessions. Stent placement was successful in 96.5% of cases. Procedural complications were observed in 13 patients (11.3%) and six patients (5.2%) needed additional percutaneous drainage. No patients reported recurrent WON post-treatment. Univariate analysis indicated a significant correlation between debris percentage and the need for additional drainage and long-term success (p <0.001). The number of endoscopic sessions correlated significantly with debris percentage (p < 0.001). CONCLUSIONS: Preprocedural imaging, particularly debris percentage within WON, significantly predicts the number of endoscopic sessions, the need for further percutaneous drainage, and overall long-term success.

Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) Revisited: In-Flight Calibrations, Lessons Learned and Scientific Advances.

The Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) on both the Van Allen Probes spacecraft is a time-of-flight versus total energy instrument that provided ion composition data over the ring current energy (∼7 keV to ∼1 MeV), and electrons over the energy range ∼25 keV to ∼1 MeV throughout the duration of the mission (2012 - 2019). In this paper we present instrument calibrations, implemented after the Van Allen Probes mission was launched. In particular, we discuss updated rate dependent corrections, possible contamination by "accidentals" rates, and caveats concerning the use of certain products. We also provide a summary of the major advances in ring current science, obtained from RBSPICE observations, and their implications for the future of inner magnetosphere exploration.

Hepatic Steatosis After Partial Pancreatectomy in a Cohort of Patients with Intraductal Papillary Mucinous Neoplasm.

Background/Aims: Nonalcoholic fatty liver disease (NAFLD) has been observed in patients after partial pancreatectomy. Previous studies have been performed on oncologic patients who underwent partial pancreatectomy and received adjuvant chemotherapy. By studying a cohort of patients with intraductal papillary mucinous neoplasms (IPMNs) who did not receive chemotherapy, the authors investigate the isolated effect of partial pancreatectomy on the development of fatty liver. Methods: A retrospective search for patients with pancreatic IPMNs who underwent partial pancreatectomy at an academic center from 2006 to 2014 identified 63 patients, including 42 who had pancreaticoduodenectomy (PD) and 21 who had distal pancreatectomy (DP). Fourteen patients with preoperative hepatic steatosis, diabetes, obesity, on steroid therapy, history of malignancy, or incomplete data were excluded. No patient received chemotherapy. Liver fat signal fraction (LFSF) was computed by the Dixon method using pre- and postoperative in- and out-of-phase MRI. Results: Of the 49 patients included in the study, 29 (59%) underwent PD and 20 (41%) underwent DP. A total of 17 patients (34%) developed fatty liver after surgery. The entire cohort developed significant weight loss, 72.1 versus 69.4 kg (P < 0.01). Postoperatively, there was significant increase in LFSF, 1.3% versus 9.6% following PD (P < 0.01), and 2.1% versus 9.4% following DP (P = 0.01). Conclusion: Partial pancreatectomy increases the risk of NAFLD independent of chemotherapy-induced hepatotoxicity. The underlying mechanism remains unclear and possibly related to pancreatic exocrine insufficiency and malnutrition.

Alcoholic vs. Nonalcoholic Steatohepatitis: Vascular Branching Heterogeneity on Magnetic Resonance Imaging as a Diagnostic Marker.

Background and Aims: Distinguishing alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH) with biopsy alone is often difficult without a reliable clinical context. A novel finding on liver imaging, perivascular branching heterogeneity, has shown promise in distinguishing between these chronic liver diseases. Our study investigated the role of this finding on imaging to differentiate between ASH and NASH. The aim of this study was to determine the utility and reproducibility of this novel radiographic marker to help distinguish ASH from NASH. Methods: This was a retrospective cohort study conducted between 2016 and 2020 in patients with both liver biopsy-confirmed steatohepatitis/chronic hepatitis and abdominal magnetic resonance imaging within 13 months of each other. Two radiologists, blinded to patient clinical history and diagnosis, categorized the appearance of the liver as: 1- homogeneity, 2- mild heterogeneity, 3- moderate heterogeneity, 4- possible perivascular branching, 5- definite perivascular branching. Results: Of the 90 patients in the study, 60 were identified as NASH and 30 as ASH. The area under the curve (AUC) for both reader 1 and 2 when using the 5-point scale was 0.69 (CI: 0.56-0.82, p=0.006) and 0.72 (CI: 0.60-0.85, p=0.001), respectively. The positive predictive value (PPV) for identification of ASH when scoring 5 was 64.7% and 66.7% for reader 1 and 2, respectively. Interclass correlation coefficient was 0.74 in patients with ASH, indicating moderate reliability among both readers. Conclusions: Identification of this perivascular branching pattern on imaging is a promising novel diagnostic marker that can be used with other methods to help distinguish between ASH and NASH.

The Early-Enhancing Hepatic Vein: Differentiating Focal Nodular Hyperplasia and Hepatic Adenoma With Pathologic Validation in MRI.

BACKGROUND: Focal nodular hyperplasia (FNH) and hepatic adenoma (HA) are two common benign liver lesions with different management options. In particular, resection is considered for large HA lesions to avoid possible bleeding complications or rarely malignant degeneration. PURPOSE: To determine whether early enhancement of a draining hepatic vein (EDHV) and absence of perilesional enhancement (PLE) on arterial phase MR images are useful for distinguishing FNH from HA. STUDY TYPE: Retrospective. POPULATION: A total of 34 patients: 16 with FNH and 18 with HA lesions. FIELD STRENGTH/SEQUENCE: A1.5 T, axial T1 fat-suppressed arterial postcontrast. ASSESMENT: Four abdominal radiologists blinded to pathologic diagnosis assessed for the presence or absence of EDHV in association with the lesion, definitively characterized by pathology. This was considered present if contrast could be identified in a hepatic vein contiguous with the lesion in question. Secondarily, PLE was evaluated. STATISTICAL TESTS: Fleiss's multirater kappa statistic, Chi-squared statistic, Phi-coefficient. Significance level P < 0.05. RESULTS: Considering all observations obtained from the four readers, an EDHV was identified with FNH 48.5% of the time. EDHV was seen with HA in 8.8% of cases. PLE was seen with significantly greater frequency in HA. The presence of an EDHV was associated with the absence of PLE. DATA CONCLUSION: In a lesion that may be either an FNH or HA, confident identification on arterial phase images of an EDHV should lead the reader to favor FNH, while the presence PLE should dissuade the reader from FNH. EVIDENCE LEVEL: 4. TECHNICAL EFFICACY: Stage 2.

LI-RADS: Looking Back, Looking Forward.

Since its initial release in 2011, the Liver Imaging Reporting and Data System (LI-RADS) has evolved and expanded in scope. It started as a single algorithm for hepatocellular carcinoma (HCC) diagnosis with CT or MRI with extracellular contrast agents and has grown into a multialgorithm network covering all major liver imaging modalities and contexts of use. Furthermore, it has developed its own lexicon, report templates, and supplementary materials. This article highlights the major achievements of LI-RADS in the past 11 years, including adoption in clinical care and research across the globe, and complete unification of HCC diagnostic systems in the United States. Additionally, the authors discuss current gaps in knowledge, which include challenges in surveillance, diagnostic population definition, perceived complexity, limited sensitivity of LR-5 (definite HCC) category, management implications of indeterminate observations, challenges in reporting, and treatment response assessment following radiation-based therapies and systemic treatments. Finally, the authors discuss future directions, which will focus on mitigating the current challenges and incorporating advanced technologies. Tha authors envision that LI-RADS will ultimately transform into a probability-based system for diagnosis and prognostication of liver cancers that will integrate patient characteristics and quantitative imaging features, while accounting for imaging modality and contrast agent.

Science of the Van Allen Probes Science Operations Centers.

The Van Allen Probes mission operations materialized through a distributed model in which operational responsibility was divided between the Mission Operations Center (MOC) and separate instrument specific SOCs. The sole MOC handled all aspects of telemetering and receiving tasks as well as certain scientifically relevant ancillary tasks. Each instrument science team developed individual instrument specific SOCs proficient in unique capabilities in support of science data acquisition, data processing, instrument performance, and tools for the instrument team scientists. In parallel activities, project scientists took on the task of providing a significant modeling tool base usable by the instrument science teams and the larger scientific community. With a mission as complex as Van Allen Probes, scientific inquiry occurred due to constant and significant collaboration between the SOCs and in concert with the project science team. Planned cross-instrument coordinated observations resulted in critical discoveries during the seven-year mission. Instrument cross-calibration activities elucidated a more seamless set of data products. Specific topics include post-launch changes and enhancements to the SOCs, discussion of coordination activities between the SOCs, SOC specific analysis software, modeling software provided by the Van Allen Probes project, and a section on lessons learned. One of the most significant lessons learned was the importance of the original decision to implement individual team SOCs providing timely and well-documented instrument data for the NASA Van Allen Probes Mission scientists and the larger magnetospheric and radiation belt scientific community.

Beyond the Liver Function Tests: A Radiologist's Guide to the Liver Blood Tests.

Liver blood tests (often also known as liver chemistries, liver tests, or the common misnomer liver function tests) are routinely used in diagnosis and management of hepatobiliary disease. Abnormal liver blood test results are often the first indicator of hepatobiliary disease and a common indication for abdominal imaging with US, CT, or MRI. Most of the disease entities can be categorized into hepatocellular or cholestatic patterns, with characteristic traits on liver blood tests. Each pattern has a specific differential, which can help narrow the differential diagnosis when combined with the clinical history and imaging findings. This article reviews the major liver blood tests as well as a general approach to recognizing common patterns of hepatobiliary disease within these tests (hepatocellular, cholestatic, acute liver failure, isolated hyperbilirubinemia). Examples of hepatobiliary disease with hepatocellular or cholestatic patterns are presented with characteristic test abnormalities and imaging findings. The commonly encountered scenario of chronic hepatitis with possible fibrosis is also reviewed, with discussion of potential further imaging such as elastography. The role of liver blood tests and imaging in evaluating complications of hepatic transplant is also discussed. Overall, integrating liver blood test patterns with imaging findings can help the radiologist accurately diagnose hepatobiliary disease, especially in cases where imaging findings may not allow differentiation between different entities. ©RSNA, 2021.

Biliary excretion of gadobenate dimeglumine causing degradation of magnetic resonance cholangiopancreatography (MRCP).

PURPOSE: To assess the effect of gadobenate dimeglumine on magnetic resonance cholangiopancreatography (MRCP) and determine an appropriate time frame for performing MRCP sequences. MATERIALS AND METHODS: 2D MRCP sequences obtained after intravenous administration of gadobenate dimeglumine or gadobutrol over 14 months were reviewed retrospectively in randomized order by five abdominal radiologists, using a 3-point scale to rate biliary and pancreatic duct clarity (1 = no-, 2 = limited-, 3 = good visualization). Intraclass correlation coefficients were computed and mean scores were compared for both agents. For gadobenate dimeglumine exams, time delays between arterial phase and MRCP acquisition times were analyzed concerning duct clarity. For gadobutrol, only exams with delays ≥ 15 min were included. RESULTS: 134 exams (107 gadobenate dimeglumine, 27 gadobutrol) were included. Moderate reliability for pancreatic duct visualization and excellent reliability for visualization of intrahepatic bile ducts and upper and lower extrahepatic bile ducts were noted. No difference in mean scores was noted for pancreatic duct visualization (p = 0.66). Bile duct segment scores were lower with gadobenate dimeglumine (mean: 2.1-2.6) compared with gadobutrol (mean: 2.8-2.9) (p ≤ 0.006). For gadobenate dimeglumine, visualization scores varied depending on the delay between the arterial phase and MRCP acquisition (p ≤ 0.047). Good visualization for all bile duct segments was noted with delays of 7.2-9.4 min (95% confidence interval; mean 8.3 min). CONCLUSION: Bile duct clarity degraded on MRCP images with an increasing delay following gadobenate dimeglumine injection. 2D MRCP, thus, should be performed within 7.2 min after obtaining the arterial phase sequence to ensure good visualization of the entire biliary system.

Retrospective comparison of EASL 2018 and LI-RADS 2018 for the noninvasive diagnosis of hepatocellular carcinoma using magnetic resonance imaging.

PURPOSE: We compared the diagnostic performances of the European Association for the Study of the Liver (EASL) 2018 and Liver Imaging Reporting and Data System (LI-RADS) 2018 criteria on magnetic resonance imaging (MRI) for the noninvasive diagnosis of hepatocellular carcinoma (HCC) in high-risk patients and evaluated the difference in diagnostic value between MRI with extracellular contrast agents (ECA-MRI) and MRI with hepatobiliary agents (HBA-MRI). METHODS: This study included 382 observations from 298 patients at high risk for HCC who underwent preoperative multiphasic contrast-enhanced MRI between January 2015 and December 2016. Two readers assessed all observations according to the EASL 2018 and LI-RADS 2018 criteria, and the per-observation diagnostic performances were compared. RESULTS: On ECA-MRI, the LR-5 category of LI-RADS 2018 showed significantly higher sensitivity (78.9% vs. 71.5%, p = 0.005) and accuracy (81.7% vs. 75.0%, p = 0.003) for the diagnosis of HCC than the EASL 2018. On HBA-MRI, the diagnostic performances of the EASL 2018 and LR-5 of LI-RADS 2018 were not significantly different. When using EASL 2018, no statistically significant differences were observed in the diagnostic performances between ECA-MRI and HBA-MRI; however, when using the LR-5 of LI-RADS 2018, ECA-MRI had a higher sensitivity (78.9% vs. 67.5%, p = 0.029) than HBA-MRI. CONCLUSIONS: On ECA-MRI, the LR-5 category of LI-RADS 2018 provides better sensitivity and accuracy than the EASL 2018 for diagnosing HCC. EASL 2018 provides comparable diagnostic performances between ECA-MRI and HBA-MRI, but the LR-5 category of LI-RADS 2018 provides better sensitivity on ECA-MRI than on HBA-MRI.

Liver MR Elastography Technique and Image Interpretation: Pearls and Pitfalls.

Liver MR elastography is an imaging technique used to measure liver stiffness in the evaluation for possible fibrosis or cirrhosis. Liver stiffness measurement (LSM) is useful for predicting the stage of liver fibrosis. However, obtaining and reporting accurate and reliable LSMs with MR elastography require an understanding of the three core components of liver MR elastography: optimization of imaging technique, prompt quality control of images, and proper interpretation and reporting of elastogram findings. When performing MR elastography, six important technical parameters that should be optimized are patient fasting before the examination, proper passive driver placement, proper MR elastography section positioning over the largest area of the liver, use of MR elastography-related sequences at end expiration, choosing the best timing of the MR elastography sequence, and optimization of several essential pulse sequence parameters. As soon as the MR elastography examination is performed, the elastograms should be reviewed to ensure that they are of diagnostic quality so that corrective steps can be taken, if needed, and MR elastography can be repeated before the diagnostic portion of the examination concludes. Finally, the interpreting radiologist needs to understand and be able to perform the proper technique for LSMs, including determining which areas of the liver to include or avoid in the measurements; knowing which conditions, other than fibrosis or cirrhosis, can increase liver stiffness; and understanding how to report elastography results. This article reviews the proper technique for performing liver MR elastography and subsequent quality control assessment, as well as the principles for interpreting and reporting studies. This review may be helpful for implementing and operating a clinical liver MR elastography service.Online supplemental material is available for this article.©RSNA, 2019.

LI-RADS: a conceptual and historical review from its beginning to its recent integration into AASLD clinical practice guidance.

The Liver Imaging Reporting and Data System (LI-RADS®) is a comprehensive system for standardizing the terminology, technique, interpretation, reporting, and data collection of liver observations in individuals at high risk for hepatocellular carcinoma (HCC). LI-RADS is supported and endorsed by the American College of Radiology (ACR). Upon its initial release in 2011, LI-RADS applied only to liver observations identified at CT or MRI. It has since been refined and expanded over multiple updates to now also address ultrasound-based surveillance, contrast-enhanced ultrasound for HCC diagnosis, and CT/MRI for assessing treatment response after locoregional therapy. The LI-RADS 2018 version was integrated into the HCC diagnosis, staging, and management practice guidance of the American Association for the Study of Liver Diseases (AASLD). This article reviews the major LI-RADS updates since its 2011 inception and provides an overview of the currently published LI-RADS algorithms.

CT/MR LI-RADS 2018: clinical implications and management recommendations.

Unique among solid organ tumors, hepatocellular carcinoma (HCC), may be diagnosed by imaging alone, without the need for biopsy. The Liver Imaging Reporting and Data System (LI-RADS) was developed to provide high-specificity diagnosis of HCC based on imaging while also standardizing the assessment and reporting of the entire spectrum of lesions and pseudolesions encountered in patients at risk for this malignancy. In this pictorial review, we discuss management recommendations associated with CT/MR LI-RADS observations. We emphasize the rationale for the recommendations and the role of multidisciplinary management discussion, and we provide a framework for standardized reporting. Management of patients who undergo ultrasound (US) for screening and surveillance or those who undergo diagnostic contrast-enhanced ultrasound (CEUS) is beyond the scope of this paper.

Pitfalls in liver MRI: Technical approach to avoiding misdiagnosis and improving image quality.

The following is an illustrative review of common pitfalls in liver MRI that may challenge interpretation. This article reviews common technical and diagnostic challenges encountered when interpreting dynamic multiphasic T1 -weighted imaging, hepatobiliary phase imaging, and diffusion-weighted imaging of the liver. Additionally, each section includes suggestions for avoiding diagnostic and technical errors. Level of Evidence: 5 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:41-58.

Introduction to the Liver Imaging Reporting and Data System for Hepatocellular Carcinoma.

The Liver Imaging Reporting And Data System (LI-RADS) was created with the support of the American College of Radiology (ACR) to standardize the acquisition, interpretation, reporting, and data collection for imaging examinations in patients at risk for hepatocellular carcinoma (HCC). A comprehensive and rigorous system developed by radiologists, hepatologists, pathologists, and surgeons, LI-RADS addresses a wide range of imaging contexts. Currently, 4 algorithms are available publicly on the ACR website: ultrasound for HCC surveillance, computed tomography and magnetic resonance imaging for HCC diagnosis and tumor staging, contrast-enhanced ultrasound for HCC diagnosis, and computed tomography/magnetic resonance imaging for treatment response assessment. Each algorithm is supported by a decision tree, categorization table, lexicon, atlas, technical requirements, and reporting and management guidance. Category codes reflecting the relative probability of HCC and malignancy are assigned to imaging-detected liver observations, with emerging evidence suggesting that LI-RADS accurately stratifies HCC and malignancy probabilities. LI-RADS is an evolving system and has been updated and refined iteratively since 2011 based on scientific evidence, expert opinion, and user feedback, with input from the American Association for the Study of Liver Diseases and the Organ Procurement Transplantation Network/United Network for Organ Sharing. Concurrent with its most recent update, LI-RADS was integrated into the American Association for the Study of Liver Diseases HCC guidance released in 2018. We anticipate continued refinement of LI-RADS and progressive adoption by radiologists worldwide, with the eventual goal of culminating in a single unified system for international use.

Liver Imaging Reporting and Data System (LI-RADS) Version 2018: Imaging of Hepatocellular Carcinoma in At-Risk Patients.

The Liver Imaging Reporting and Data System (LI-RADS) is composed of four individual algorithms intended to standardize the lexicon, as well as reporting and care, in patients with or at risk for hepatocellular carcinoma in the context of surveillance with US; diagnosis with CT, MRI, or contrast material-enhanced US; and assessment of treatment response with CT or MRI. This report provides a broad overview of LI-RADS, including its historic development, relationship to other imaging guidelines, composition, aims, and future directions. In addition, readers will understand the motivation for and key components of the 2018 update.

White paper of the Society of Abdominal Radiology hepatocellular carcinoma diagnosis disease-focused panel on LI-RADS v2018 for CT and MRI.

The Liver Imaging and Reporting Data System (LI-RADS) is a comprehensive system for standardizing the terminology, technique, interpretation, reporting, and data collection of liver imaging with the overarching goal of improving communication, clinical care, education, and research relating to patients at risk for or diagnosed with hepatocellular carcinoma (HCC). In 2018, the American Association for the Study of Liver Diseases (AASLD) integrated LI-RADS into its clinical practice guidance for the imaging-based diagnosis of HCC. The harmonization between the AASLD and LI-RADS diagnostic imaging criteria required minor modifications to the recently released LI-RADS v2017 guidelines, necessitating a LI-RADS v2018 update. This article provides an overview of the key changes included in LI-RADS v2018 as well as a look at the LI-RADS v2018 diagnostic algorithm and criteria, technical recommendations, and management suggestions. Substantive changes in LI-RADS v2018 are the removal of the requirement for visibility on antecedent surveillance ultrasound for LI-RADS 5 (LR-5) categorization of 10-19 mm observations with nonrim arterial phase hyper-enhancement and nonperipheral "washout", and adoption of the Organ Procurement and Transplantation Network definition of threshold growth (≥ 50% size increase of a mass in ≤ 6 months). Nomenclatural changes in LI-RADS v2018 are the removal of -us and -g as LR-5 qualifiers.

LI-RADS 2017: An update.

The computed tomography / magnetic resonance imaging (CT/MRI) Liver Imaging Reporting & Data System (LI-RADS) is a standardized system for diagnostic imaging terminology, technique, interpretation, and reporting in patients with or at risk for developing hepatocellular carcinoma (HCC). Using diagnostic algorithms and tables, the system assigns to liver observations category codes reflecting the relative probability of HCC or other malignancies. This review article provides an overview of the 2017 version of CT/MRI LI-RADS with a focus on MRI. The main LI-RADS categories and their application will be described. Changes and updates introduced in this version of LI-RADS will be highlighted, including modifications to the diagnostic algorithm and to the optional application of ancillary features. Comparisons to other major diagnostic systems for HCC will be made, emphasizing key similarities, differences, strengths, and limitations. In addition, this review presents the new Treatment Response algorithm, while introducing the concepts of MRI nonviability and viability. Finally, planned future directions for LI-RADS will be outlined. LEVEL OF EVIDENCE: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018;47:1459-1474.