Publications by authors named "Kathryn J Fowler"

143 Publications

Quantitative magnetic resonance imaging for chronic liver disease.

Br J Radiol 2021 Feb 26:20201377. Epub 2021 Feb 26.

Department of Radiology, Liver Imaging Group, University of California San Diego, San Diego, CA, USA.

Chronic liver disease (CLD) has rapidly increased in prevalence over the past two decades, resulting in significant morbidity and mortality worldwide. Historically, the clinical gold standard for diagnosis, assessment of severity, and longitudinal monitoring of CLD has been liver biopsy with histological analysis, but this approach has limitations that may make it suboptimal for clinical and research settings. Magnetic resonance (MR)-based biomarkers can overcome the limitations by allowing accurate, precise, and quantitative assessment of key components of CLD without the risk of invasive procedures. This review briefly describes the limitations associated with liver biopsy and the need for non-invasive biomarkers. It then discusses the current state-of-the-art for MRI-based biomarkers of liver iron, fat, and fibrosis, and inflammation.
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http://dx.doi.org/10.1259/bjr.20201377DOI Listing
February 2021

Repeatability and accuracy of various region-of-interest sampling strategies for hepatic MRI proton density fat fraction quantification.

Abdom Radiol (NY) 2021 Feb 20. Epub 2021 Feb 20.

Department of Radiology, University of California San Diego, 9500 Gilman Drive #0888, La Jolla, CA, 92093-0888, USA.

Purpose: To evaluate repeatability of ROI-sampling strategies for quantifying hepatic proton density fat fraction (PDFF) and to assess error relative to the 9-ROI PDFF.

Methods: This was a secondary analysis in subjects with known or suspected nonalcoholic fatty liver disease who underwent MRI for magnitude-based hepatic PDFF quantification. Each subject underwent three exams, each including three acquisitions (nine acquisitions total). An ROI was placed in each hepatic segment on the first acquisition of the first exam and propagated to other acquisitions. PDFF was calculated for each of 511 sampling strategies using every combination of 1, 2, …, all 9 ROIs. Intra- and inter-exam intra-class correlation coefficients (ICCs) and repeatability coefficients (RCs) were estimated for each sampling strategy. Mean absolute error (MAE) was estimated relative to the 9-ROI PDFF. Strategies that sampled both lobes evenly ("balanced") were compared with those that did not ("unbalanced") using two-sample t tests.

Results: The 29 enrolled subjects (23 male, mean age 24 years) had mean 9-ROI PDFF 11.8% (1.1-36.3%). With more ROIs, ICCs increased, RCs decreased, and MAE decreased. Of the 60 balanced strategies with 4 ROIs, all (100%) achieved inter- and intra-exam ICCs > 0.998, 55 (92%) achieved intra-exam RC < 1%, 50 (83%) achieved inter-exam RC < 1%, and all (100%) achieved MAE < 1%. Balanced sampling strategies had higher ICCs and lower RCs, and lower MAEs than unbalanced strategies in aggregate (p < 0.001 for comparisons between balanced vs. unbalanced strategies).

Conclusion: Repeatability improves and error diminishes with more ROIs. Balanced 4-ROI strategies provide high repeatability and low error.
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http://dx.doi.org/10.1007/s00261-021-02965-5DOI Listing
February 2021

Targetoid appearance on T2-weighted imaging and signs of tumor vascular involvement: diagnostic value for differentiating HCC from other primary liver carcinomas.

Eur Radiol 2021 Feb 15. Epub 2021 Feb 15.

Department of Radiology, University of California San Diego, 200 W Arbor Dr., San Diego, CA, 92103, USA.

Objectives: To evaluate targetoid appearance on T2-weighted imaging and signs of tumor vascular involvement as potential new LI-RADS features for differentiating hepatocellular carcinoma (HCC) from other non-HCC primary liver carcinomas (PLCs).

Methods: This IRB-approved, retrospective study was performed at two liver transplant centers. The final population included 375 patients with pathologically proven lesions imaged between 2007 and 2017 with contrast-enhanced CT or MRI. The cohort consisted of 165 intrahepatic cholangiocarcinomas and 74 combined hepatocellular-cholangiocarcinomas, with the addition of 136 HCCs for control. Two abdominal radiologists (R1; R2) independently reviewed the imaging studies (112 CT; 263 MRI) and recorded the presence of targetoid appearance on T2-weighted images and features of tumor vascular involvement including encasement, narrowing, tethering, occlusion, and obliteration. The sensitivity and specificity of each feature were calculated for the diagnosis of non-HCC PLCs. Cohen's kappa (k) test was used to assess inter-reader agreement.

Results: The sensitivity of targetoid appearance on T2-weighted images for the diagnosis of non-HCC PLCs was 27.5% and 32.6% (R1 and R2) and the specificity was 98.2% and 97.3% (R1 and R2). Among the features of tumor vascular involvement, those providing the highest sensitivity for non-HCC PLCs were vascular encasement (R1: 34.3%; R2: 37.2%) and obliteration (R1: 25.5%; R2: 29.7%). The highest specificity for non-HCC PLCs was provided by tethering (R1: 100%; R2: 97.1%) and occlusion (R1: 99.3%; R2: 99.3%). The inter-reader agreement was moderate to substantial (k = 0.48-0.77).

Conclusions: Targetoid appearance on T2-weighted images and features of tumor vascular involvement demonstrated high specificity for non-HCC malignancy.

Key Points: • Targetoid appearance on T2-weighted imaging and signs of tumor vascular involvement have high specificity (92-100%) for the diagnosis of non-HCC PLCs, regardless of the presence of liver risk factors. • In the subset of patients with risk factors for HCC, the sensitivity of signs of tumor vascular involvement decreases for both readers (1.7-20.3%), while the specificity increases reaching values higher than 94.2%. • The inter-reader agreement is substantial for targetoid appearance on T2-weighted images (k = 0.74) and moderate to substantial for signs of tumor vascular involvement (k = 0.48-0.77).
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http://dx.doi.org/10.1007/s00330-021-07743-xDOI Listing
February 2021

CNN color-coded difference maps accurately display longitudinal changes in liver MRI-PDFF.

Eur Radiol 2021 Jan 15. Epub 2021 Jan 15.

Liver Imaging Group, Department of Radiology, University of California, San Diego, La Jolla, CA, USA.

Objectives: To assess the feasibility of a CNN-based liver registration algorithm to generate difference maps for visual display of spatiotemporal changes in liver PDFF, without needing manual annotations.

Methods: This retrospective exploratory study included 25 patients with suspected or confirmed NAFLD, who underwent PDFF-MRI at two time points at our institution. PDFF difference maps were generated by applying a CNN-based liver registration algorithm, then subtracting follow-up from baseline PDFF maps. The difference maps were post-processed by smoothing (5 cm round kernel) and applying a categorical color scale. Two fellowship-trained abdominal radiologists and one radiology resident independently reviewed difference maps to visually determine segmental PDFF change. Their visual assessment was compared with manual ROI-based measurements of each Couinaud segment and whole liver PDFF using intraclass correlation (ICC) and Bland-Altman analysis. Inter-reader agreement for visual assessment was calculated (ICC).

Results: The mean patient age was 49 years (12 males). Baseline and follow-up PDFF ranged from 2.0 to 35.3% and 3.5 to 32.0%, respectively. PDFF changes ranged from - 20.4 to 14.1%. ICCs against the manual reference exceeded 0.95 for each reader, except for segment 2 (2 readers ICC = 0.86-0.91) and segment 4a (reader 3 ICC = 0.94). Bland-Altman limits of agreement were within 5% across all three readers. Inter-reader agreement for visually assessed PDFF change (whole liver and segmental) was excellent (ICCs > 0.96), except for segment 2 (ICC = 0.93).

Conclusions: Visual assessment of liver segmental PDFF changes using a CNN-generated difference map strongly agreed with manual estimates performed by an expert reader and yielded high inter-reader agreement.

Key Points: • Visual assessment of longitudinal changes in quantitative liver MRI can be performed using a CNN-generated difference map and yields strong agreement with manual estimates performed by expert readers.
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http://dx.doi.org/10.1007/s00330-020-07649-0DOI Listing
January 2021

Improved survival following transarterial radioembolization of infiltrative-appearance hepatocellular carcinoma.

Abdom Radiol (NY) 2021 Jan 1. Epub 2021 Jan 1.

Department of Radiology, University of Kentucky, 800 Rose Street, Lexington, KY, 40536, USA.

Purpose: Infiltrative-appearance hepatocellular carcinoma presents a challenge to clinicians as diagnostic criteria continue to evolve and evidence-based treatment guidelines have yet to be established. While transarterial radioembolization has shown efficacy in hepatocellular carcinoma, many studies exclude infiltrative-appearance HCC in their analysis. The purpose of this study was to describe imaging features of infiltrative-appearance hepatocellular carcinoma and evaluate effects of radioembolization on survival.

Methods: In a retrospective review, infiltrative HCC patients treated from 2008 to 2017 were identified. Patients were divided into two groups: TARE versus systemic therapy/palliative care. Demographics, dates of diagnosis/expiry, albumin, international normalized ratio (INR), sodium, alpha-fetoprotein (AFP), creatinine, Child-Pugh class, model for end-stage liver disease (MELD) score, bilirubin, radiation dose and volume were collected. Patients with bilirubin > 3 were excluded. Mann-Whitney U test and Fisher's exact test assessed differences between groups. Kaplan-Meier survival and Cox proportional hazard analyses were performed.

Results: Fifty-three patients were identified, 15 underwent TARE while 38 served as control. Mean age was 60, 43 patients were male. The mean overall survival was 16.2 months for the TARE group and 5.3 months for the control group (Log-rank p < 0.0001). Cox proportional regression analysis revealed significant associations between survival and albumin (HR 0.210, 0.052-0.839, p = 0.027), Child-Pugh class B (HR 0.196, 0.055-0.696, p = 0.012), sorafenib (HR 0.106, 0.031-0.360, p < 0.001), and number of affected liver lobes (HR 1.864, 1.387-2.506, p < 0.001).

Conclusions: Transarterial radioembolization for infiltrative HCC improves life expectancy compared to treatment with comfort measures or systemic therapy.
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http://dx.doi.org/10.1007/s00261-020-02870-3DOI Listing
January 2021

Alternative approach of hepatocellular carcinoma surveillance: abbreviated MRI.

Hepatoma Res 2020 1;6. Epub 2020 Sep 1.

Department of Radiology, Naval Medical Center San Diego, San Diego, CA 92134, USA.

This review focuses on emerging abbreviated magnetic resonance imaging (AMRI) surveillance of patients with chronic liver disease for hepatocellular carcinoma (HCC). This surveillance strategy has been proposed as a high-sensitivity alternative to ultrasound for identification of patients with early-stage HCC, particularly in patients with cirrhosis or obesity, in whom sonographic visualization of small tumors may be compromised. Three general AMRI approaches have been developed and studied in the literature - non-contrast AMRI, dynamic contrast-enhanced AMRI, and hepatobiliary phase contrast-enhanced AMRI - each comprising a small number of selected sequences specifically tailored for HCC detection. The rationale, general technique, advantages and disadvantages, and diagnostic performance of each AMRI approach is explained. Additionally, current gaps in knowledge and future directions are discussed. Based on emerging evidence, we cautiously recommend the use of AMRI for HCC surveillance in situations where ultrasound is compromised.
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http://dx.doi.org/10.20517/2394-5079.2020.50DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7771881PMC
September 2020

Abbreviated MRI for Hepatocellular Carcinoma Screening and Surveillance.

Radiographics 2020 Nov-Dec;40(7):1916-1931

From the Liver Imaging Group, Department of Radiology, University of California San Diego, 9500 Gilman Dr, MC 0888, San Diego, CA 92093 (J.Y.A., G.M.C., M.T.B., C.B.S., K.J.F.); School of Medicine, Tufts University, Boston, Mass (M.A.P.); Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (B.T.); and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY (T.Y.).

To detect potentially curable hepatocellular carcinoma (HCC), clinical practice guidelines recommend semiannual surveillance US of the liver in adult patients at risk for developing this malignancy, such as those with cirrhosis and some patients with chronic hepatitis B infection. However, cirrhosis and a large body habitus, both of which are increasingly prevalent in the United States and the rest of the world, may impair US visualization of liver lesions and reduce the sensitivity of surveillance with this modality. The low sensitivity of US for detection of early-stage HCC contributes to delayed diagnosis and increased mortality. Abbreviated MRI, a shortened MRI protocol tailored for early-stage detection of HCC, has been proposed as an alternative surveillance option that provides high sensitivity and specificity. Abbreviated MRI protocols include fewer sequences than a complete multiphase MRI examination and are specifically designed to identify small potentially curable HCCs that may be missed at US. Three abbreviated MRI strategies have been studied: nonenhanced, dynamic contrast material-enhanced, and hepatobiliary phase contrast-enhanced abbreviated MRI. Retrospective studies have shown that simulated abbreviated MRI provides high sensitivity and specificity for early-stage HCC, mostly in nonsurveillance cohorts. If it is supported by scientific evidence in surveillance populations, adoption of abbreviated MRI could advance clinical practice by increasing early detection of HCC, allowing effective treatment and potentially prolonging life in the growing number of individuals with this cancer. RSNA, 2020.
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http://dx.doi.org/10.1148/rg.2020200104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7714535PMC
November 2021

Online Liver Imaging Course; Pivoting to Transform Radiology Education During the SARS-CoV-2 Pandemic.

Acad Radiol 2021 01 6;28(1):119-127. Epub 2020 Oct 6.

Office of Educational Programs, McGovern Medical School at UT Health, Houston, Texas.

Purpose: The SARS-CoV-2 pandemic has drastically disrupted radiology in-person education. The purpose of this study was to assess the implementation of a virtual teaching method using available technology and its role in the continuity of education of practicing radiologists and trainees during the pandemic.

Methods: The authors created the Online Liver Imaging Course (OLIC) that comprised 28 online comprehensive lectures delivered in real-time and on-demand over six weeks. Radiologists and radiology trainees were asked to register to attend the live sessions. At the end of the course, we conducted a 46-question survey among registrants addressing their training level, perception of virtual conferencing, and evaluation of the course content.

Results: One thousand four hundred and thirty four radiologists and trainees completed interest sign up forms before the start of the course with the first webinar having the highest number of live attendees (343 people). On average, there were 89 live participants per session and 750 YouTube views per recording (as of July 9, 2020). After the end of the course, 487 attendees from 37 countries responded to the postcourse survey for an overall response rate of (33%). Approximately (63%) of participants were practicing radiologists while (37%) were either fellows or residents and rarely medical students. The overwhelming majority (97%) found the OLIC webinar series to be beneficial. Essentially all attendees felt that the webinar sessions met (43%) or exceeded (57%) their expectations. When asked about their perception of virtual conferences after attending OLIC lectures, almost all attendees (99%) enjoyed the virtual conference with a majority (61%) of the respondents who enjoyed the virtual format more than in-person conferences, while (38%) enjoyed the webinar format but preferred in-person conferences. When asked about the willingness to attend virtual webinars in the future, (84%) said that they would attend future virtual conferences even if in-person conferences resume while (15%) were unsure.

Conclusion: The success of the OLIC, attributed to many factors, indicates that videoconferencing technology provides an inexpensive alternative to in-person radiology conferences. The positive responses to our postcourse survey suggest that virtual education will remain to stay. Educational institutions and scientific societies should foster such models.
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http://dx.doi.org/10.1016/j.acra.2020.10.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7538097PMC
January 2021

Imaging Diagnosis of Hepatocellular Carcinoma: The Liver Imaging Reporting and Data System, Why and How?

Clin Liver Dis 2020 11 2;24(4):623-636. Epub 2020 Sep 2.

Division of Gastroenterology & Hepatology, University of California, 9500 Gilman Drive, San Diego, CA 92093, USA. Electronic address:

The Liver Imaging Reporting and Data System (LI-RADS) provides standardized lexicon, technique, interpretation, and reporting of liver imaging in patients at risk for hepatocellular carcinoma (HCC). When applied to at-risk populations, LI-RADS achieves higher than 95% positive predictive value for the noninvasive diagnosis of HCC on computed tomography (CT), MRI and contrast-enhanced ultrasound (CEUS). This article focuses on similarities and differences between the CT/MRI diagnostic algorithm (CT/MRI LI-RADS) and the CEUS diagnostic algorithm (CEUS LI-RADS) to inform health care professionals for efficient and appropriate clinical decisions through the management of patients at risk.
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http://dx.doi.org/10.1016/j.cld.2020.07.002DOI Listing
November 2020

Change in MRI-PDFF and Histologic Response in Patients With Nonalcoholic Steatohepatitis: A Systematic Review and Meta-Analysis.

Clin Gastroenterol Hepatol 2020 Aug 31. Epub 2020 Aug 31.

Division of Gastroenterology and Hepatology, Department of Medicine, University of California, San Diego, La Jolla, California; Division of Epidemiology, Department of Family Medicine and Public Health, University of California, San Diego, La Jolla, California; NAFLD Research Center, University of California, San Diego, La Jolla, California. Electronic address:

Background & Aims: Magnetic resonance imaging proton density fat fraction (MRI-PDFF) offers promise as a non-invasive biomarker of treatment response in early-phase nonalcoholic steatohepatitis (NASH) trials. We performed a systematic review to quantify the association between a ≥ 30% reduction in MRI-PDFF and histologic response in NASH.

Methods: We searched the Cochrane Library, Embase, Medline and trial registries through May 2020 for early-phase clinical trials that incorporated MRI-PDFF and examined histologic response following intervention in adults with NASH. Subjects were classified as MRI-PDFF responders (relative decline in liver fat ≥30%) or non-responders (relative decline in liver fat <30%). MRI-PDFF responders versus non-responders were compared. Primary outcome was histologic response defined as a 2-point improvement in NAFLD Activity Score with at least 1-point improvement in lobular inflammation or ballooning. Secondary outcome was NASH resolution. Proportions and random effects odds ratios (OR) with corresponding 95% confidence intervals (CI) were calculated.

Results: Seven studies met inclusion criteria, comprising 346 subjects (median age 51 years; 59% female; 46% with diabetes). MRI-PDFF responders were significantly more likely to have a histologic response (51% vs 14%, P < .001; OR 6.98, 95% CI 2.38-20.43, P < .001) and NASH resolution (41% vs 7%, P < .001; OR 5.45, 95% CI 1.53-19.46, P = .009) compared to non-responders.

Conclusions: This meta-analysis demonstrates that a ≥30% relative decline in MRI-PDFF is associated with higher odds of histologic response and NASH resolution. These results support the use of MRI-PDFF in non-invasive monitoring of treatment response in early-phase NASH clinical trials and provide helpful data for sample-size estimation for histology-based assessment.
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http://dx.doi.org/10.1016/j.cgh.2020.08.061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7914285PMC
August 2020

Gadoxetate-enhanced abbreviated MRI is highly accurate for hepatocellular carcinoma screening.

Eur Radiol 2020 Nov 25;30(11):6003-6013. Epub 2020 Jun 25.

BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

Objectives: The primary objective was to compare the performance of 3 different abbreviated MRI (AMRI) sets extracted from a complete gadoxetate-enhanced MRI obtained for hepatocellular carcinoma (HCC) screening. Secondary objective was to perform a preliminary cost-effectiveness analysis, comparing each AMRI set to published ultrasound performance for HCC screening in the USA.

Methods: This retrospective study included 237 consecutive patients (M/F, 146/91; mean age, 58 years) with chronic liver disease who underwent a complete gadoxetate-enhanced MRI for HCC screening in 2017 in a single institution. Two radiologists independently reviewed 3 AMRI sets extracted from the complete exam: non-contrast (NC-AMRI: T2-weighted imaging (T2wi)+diffusion-weighted imaging (DWI)), dynamic-AMRI (Dyn-AMRI: T2wi+DWI+dynamic T1wi), and hepatobiliary phase AMRI (HBP-AMRI: T2wi+DWI+T1wi during the HBP). Each patient was classified as HCC-positive/HCC-negative based on the reference standard, which consisted in all available patient data. Diagnostic performance for HCC detection was compared between sets. Estimated set characteristics, including historical ultrasound data, were incorporated into a microsimulation model for cost-effectiveness analysis.

Results: The reference standard identified 13/237 patients with HCC (prevalence, 5.5%; mean size, 33.7 ± 30 mm). Pooled sensitivities were 61.5% for NC-AMRI (95% confidence intervals, 34.4-83%), 84.6% for Dyn-AMRI (60.8-95.1%), and 80.8% for HBP-AMRI (53.6-93.9%), without difference between sets (p range, 0.06-0.16). Pooled specificities were 95.5% (92.4-97.4%), 99.8% (98.4-100%), and 94.9% (91.6-96.9%), respectively, with a significant difference between Dyn-AMRI and the other sets (p < 0.01). All AMRI methods were effective compared with ultrasound, with life-year gain of 3-12 months against incremental costs of US$ < 12,000.

Conclusions: NC-AMRI has limited sensitivity for HCC detection, while HBP-AMRI and Dyn-AMRI showed excellent sensitivity and specificity, the latter being slightly higher for Dyn-AMRI. Cost-effectiveness estimates showed that AMRI is effective compared with ultrasound.

Key Points: • Comparison of different abbreviated MRI (AMRI) sets reconstructed from a complete gadoxetate MRI demonstrated that non-contrast AMRI has low sensitivity (61.5%) compared with contrast-enhanced AMRI (80.8% for hepatobiliary phase AMRI and 84.6% for dynamic AMRI), with all sets having high specificity. • Non-contrast and hepatobiliary phase AMRI can be performed in less than 14 min (including set-up time), while dynamic AMRI can be performed in less than 17 min. • All AMRI sets were cost-effective for HCC screening in at-risk population in comparison with ultrasound.
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http://dx.doi.org/10.1007/s00330-020-07014-1DOI Listing
November 2020

Imaging diagnosis of hepatocellular carcinoma: LI-RADS.

Chin Clin Oncol 2021 Feb 9;10(1). Epub 2020 Jun 9.

Liver Imaging Group, Department of Radiology, University of California San Diego, San Diego, CA 92093, USA.

Liver cancer is the third most common cause of cancer related death worldwide, 90% being hepatocellular carcinoma (HCC) and about half of all HCCs estimated to occur in China. Imaging plays a pivotal role in the management of HCC. When stringent criteria are applied to at-risk populations, it enables HCCs to be diagnosed by imaging alone without further need of invasive histology confirmation. To optimize HCC imaging diagnosis and reporting, several systems have been proposed. The Liver Imaging Reporting and Data System (LI-RADS®) is currently the most comprehensive of these systems, providing guidance on all imaging-related aspects of HCC, from technique for acquisition, reporting, assessment of treatment response and management. For diagnosis, LI-RADS uses major and ancillary imaging features to assign hierarchical categories that communicate the relative probability of HCC to focal liver observations detected in patients at risk. Two LI-RADS algorithms yield high specificity and positive predictive value for HCC diagnosis on contrast enhanced ultrasound (CEUS), CT and MRI. The standardized lexicon and interpretation provided by LI-RADS also improve inter-reader agreement for imaging features and lesion categorization. Additionally, a LI-RADS treatment response algorithm (LR-TR) provide imaging criteria for assessment of response to locoregional therapy. LI-RADS is designed for universal adoption and in this review, we highlighted the most relevant aspects of LI-RADS for the diagnosis of HCC in clinical practice and discussed areas where LI-RADS and Asian guidelines are different.
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http://dx.doi.org/10.21037/cco-20-107DOI Listing
February 2021

ACR Appropriateness Criteria® Crohn Disease.

J Am Coll Radiol 2020 May;17(5S):S81-S99

Specialty Chair, Virginia Commonwealth University Medical Center, Richmond, Virginia.

Three common clinical scenarios involving use of imaging in Crohn disease are covered. These include the initial evaluation of Crohn disease when the diagnosis has not been previously established, the evaluation for anticipated exacerbation of known disease, and the evaluation of disease activity during therapy monitoring. The appropriateness of a given imaging modality for each scenario is rated as one of three categories (usually appropriate, may be appropriate, usually not appropriate) to help guide evaluation. Pediatric presentation of Crohn disease and the appropriateness of imaging are not covered in this document. 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.
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http://dx.doi.org/10.1016/j.jacr.2020.01.030DOI Listing
May 2020

ACR Appropriateness Criteria® Suspected Small-Bowel Obstruction.

J Am Coll Radiol 2020 May;17(5S):S305-S314

Specialty Chair, Virginia Commonwealth University Medical Center, Richmond, Virginia.

Small-bowel obstruction is a common cause of abdominal pain and accounts for a significant proportion of hospital admissions. Radiologic imaging plays the key role in the diagnosis and management of small-bowel obstruction as neither patient presentation, the clinical examination, nor laboratory testing are sufficiently sensitive or specific enough to diagnose or guide management. This document focuses on the imaging evaluation of the two most commonly encountered clinical scenarios related to small-bowel obstruction: the acute presentation and the more indolent, low-grade, or intermittent presentation. This document hopes to clarify the appropriate utilization of the many imaging procedures that are available and commonly employed in these clinical settings. 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.
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http://dx.doi.org/10.1016/j.jacr.2020.01.025DOI Listing
May 2020

Prospective comparison of longitudinal change in hepatic proton density fat fraction (PDFF) estimated by magnitude-based MRI (MRI-M) and complex-based MRI (MRI-C).

Eur Radiol 2020 Sep 21;30(9):5120-5129. Epub 2020 Apr 21.

Liver Imaging Group, Department of Radiology, University of California - San Diego, San Diego, CA, USA.

Purpose: To compare longitudinal hepatic proton density fat fraction (PDFF) changes estimated by magnitude- vs. complex-based chemical-shift-encoded MRI during a weight loss surgery (WLS) program in severely obese adults with biopsy-proven nonalcoholic fatty liver disease (NAFLD).

Methods: This was a secondary analysis of a prospective dual-center longitudinal study of 54 adults (44 women; mean age 52 years; range 27-70 years) with obesity, biopsy-proven NAFLD, and baseline PDFF ≥ 5%, enrolled in a WLS program. PDFF was estimated by confounder-corrected chemical-shift-encoded MRI using magnitude (MRI-M)- and complex (MRI-C)-based techniques at baseline (visit 1), after a 2- to 4-week very low-calorie diet (visit 2), and at 1, 3, and 6 months (visits 3 to 5) after surgery. At each visit, PDFF values estimated by MRI-M and MRI-C were compared by a paired t test. Rates of PDFF change estimated by MRI-M and MRI-C for visits 1 to 3, and for visits 3 to 5 were assessed by Bland-Altman analysis and intraclass correlation coefficients (ICCs).

Results: MRI-M PDFF estimates were lower by 0.5-0.7% compared with those of MRI-C at all visits (p < 0.001). There was high agreement and no difference between PDFF change rates estimated by MRI-M vs. MRI-C for visits 1 to 3 (ICC 0.983, 95% CI 0.971, 0.99; bias = - 0.13%, p = 0.22), or visits 3 to 5 (ICC 0.956, 95% CI 0.919-0.977%; bias = 0.03%, p = 0.36).

Conclusion: Although MRI-M underestimates PDFF compared with MRI-C cross-sectionally, this bias is consistent and MRI-M and MRI-C agree in estimating the rate of hepatic PDFF change longitudinally.

Key Points: • MRI-M demonstrates a significant but small and consistent bias (0.5-0.7%; p < 0.001) towards underestimation of PDFF compared with MRI-C at 3 T. • Rates of PDFF change estimated by MRI-M and MRI-C agree closely (ICC 0.96-0.98) in adults with severe obesity and biopsy- proven NAFLD enrolled in a weight loss surgery program. • Our findings support the use of either MRI technique (MRI-M or MRI-C) for clinical care or by individual sites or for multi-center trials that include PDFF change as an endpoint. However, since there is a bias in their measurements, the same technique should be used in any given patient for longitudinal follow-up.
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http://dx.doi.org/10.1007/s00330-020-06858-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7495399PMC
September 2020

Examining LI-RADS recommendations: should observation size only be measured on non-arterial phases?

Abdom Radiol (NY) 2020 10;45(10):3144-3154

Liver Imaging Group, Department of Radiology, Altman Clinical Translational Research Institute, 9452 Medical Center Drive, Lower Level 501, La Jolla, CA, 92037, USA.

Objective: To investigate if size measurements of liver observations is more variable in the arterial phase as suggested by LI-RADS and assess potential higher instability in categorization in this particular phase. Secondarily, to assess inter- and intra-reader agreement for size across phases.

Materials And Methods: Patients with liver cirrhosis who underwent multi-arterial phase MRI between 2017 and 2018 were retrospectively selected. Three radiologists measured liver observations in each phase, independently, in a random order. Mean size between early and late arterial phases (AP), 2, 3 and 10 min delay and the number of observations crossing the LI-RADS size thresholds (10 and 20 mm) per phase were compared using McNemar's test. Reader agreement was evaluated using intraclass correlation coefficient (ICC) and bootstrap-based comparisons. Bonferroni's correction was applied to pairwise comparisons.

Results: 94 observations (LR-3, LR-4, LR-5, and LR-M) were included. Mean sizes (mm) were late AP: 19.9 (95% CI 17.2, 24.2), 2 min delay: 19.8 (95% CI 17.1, 24.0), 3 min delay: 19.8 (95% CI 17.2, 24.0), 10 min delay: 20.2 (95% CI 17.5, 24.5) (p = 0.10-0.88). There was no difference between phases in number of observations that could have changed category due to variability in size (p = 0.546-1.000). Inter- and intra-reader agreement was excellent (ICC = 0.952-0.981).

Conclusion: Measurements of focal liver observations were consistent across all post-contrast imaging phases and we found no higher instability in LI-RADS category in any particular phase. Inter- and intra-reader agreement for size was excellent for each phase. Based on these findings, size measurement could be allowed on any post-contrast phase, including the arterial phase, if deemed appropriate by the radiologist.
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http://dx.doi.org/10.1007/s00261-020-02490-xDOI Listing
October 2020

The relationship between liver triglyceride composition and proton density fat fraction as assessed by H MRS.

NMR Biomed 2020 06 3;33(6):e4286. Epub 2020 Mar 3.

Liver Imaging Group, Department of Radiology, University of California San Diego, La Jolla, California.

The aim of this study was to estimate parameters determining liver triglyceride composition (TC) using H MRS and to assess how TC estimability is affected by proton density fat fraction (PDFF) in adults with nonalcoholic fatty liver disease (NAFLD). In this prospective single-site study, 199 adults with known or suspected NAFLD in whom other causes of liver disease were excluded underwent two H MRS STimulated Echo Acquisition Method (STEAM) sequences at 3 T. A respiratory-gated water-suppressed free breathing sequence (TE 10 ms, 16 signal averages) was used to assess TC in terms of the number of double bonds (ndb) and methylene-interrupted double bonds (nmidb), and a single breath-hold-long TR, multi-TE sequence (TR 3500 ms), which acquired five single average spectra over TE 10-30 ms, was used to estimate liver PDFF. Ndb and nmidb estimability was qualitatively assessed for each case and summarized descriptively. The consistency of ndb and nmidb estimation was examined using ROC analysis. The relationship between ndb and nmidb values and PDFF was presented graphically. Quality-of-fit of ndb and nmidb versus PDFF was evaluated by Pearson-r correlation. A significance level of 0.05 was used. In 263 H MRS examinations performed on 199 adult participants, ndb and nmidb were successfully estimated in 7/53 (13.2%) examinations with PDFF < 4%, 13/30 (43.3%) examinations with PDFF between 4% and 7%, 33/41 (80.5%) examinations with PDFF between 7% and 10%, and 124/139 (89.2%) examinations with PDFF > 10% (maximum PDFF 38.1%). Liver TC could be estimated consistently for PDFF > 6.7%. Both ndb and nmidb decreased with increasing PDFF (ndb = 2.83-0.0160·PDFF, r = -0.449, P < 0.0001); nmidb = 0.75-0.0088·PDFF, r = -0.350, P < 0.0001). In a cohort of adults with known or suspected NAFLD, liver TC becomes more saturated as PDFF increases.
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http://dx.doi.org/10.1002/nbm.4286DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211117PMC
June 2020

Editorial on "Head-to-Head Comparison of PI-RADS Version 2 and 2.1 in Transition Zone Lesions for Detection of Prostate Cancer".

J Magn Reson Imaging 2020 08 31;52(2):587-588. Epub 2020 Jan 31.

Department of Radiology, University of California San Diego, San Diego, California, USA.

Level Of Evidence: 5 TECHNICAL EFFICACY: Stage 1 J. Magn. Reson. Imaging 2020;52:587-588.
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http://dx.doi.org/10.1002/jmri.27062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7367752PMC
August 2020

Diagnostic performance of LI-RADS version 2018 in differentiating hepatocellular carcinoma from other hepatic malignancies in patients with hepatitis B virus infection.

Bosn J Basic Med Sci 2020 Aug 3;20(3):401-410. Epub 2020 Aug 3.

Liver Imaging Group, Department of Radiology, University of California at San Diego, La Jolla, California, USA.

The diagnostic performance of the Liver Imaging Reporting and Data System (LI-RADS) in differentiating hepatocellular carcinoma (HCC) from other hepatic malignancies has not been investigated in Chinese patients with chronic liver disease from hepatitis B virus (HBV) infection. The aim of this study was to evaluate the accuracy of the LI-RADS version 2018 in differentiating HCC, intrahepatic cholangiocarcinoma (ICCA), and combined HCC-cholangiocarcinoma (cHCC-CCA) in Chinese patients with HBV infection. Seventy consecutive HBV-infected patients with ICCA (n = 48) or cHCC-CCA (n = 22) who underwent contrast-enhanced magnetic resonance imaging (CE-MRI) between 2006 and 2017 were enrolled along with a comparison cohort of 70 patients with HCC and CE-MRI-matched for tumor size (10-19 mm, 20-30 mm, 31-50 mm, and >50 mm). Imaging feature frequencies for each tumor type were compared using Fisher's exact test. The classification accuracy of LR-5 and LR-M was estimated for HCC versus non-HCC (ICCA and cHCC-CCA). The interobserver agreement was good for LI-RADS categories of HCC and moderate for non-HCC. After consensus read, 66 of 70 (94%) HCCs were categorized LR-5 (including tumor in vein [TIV] with LR-5), while 42 of 48 (88%) ICCAs and 13 of 22 (59%) cHCC-CCAs were categorized LR-M (including TIV with LR-M) (p < 0.001). Thus, assignment of LR-5 provided 94% sensitivity and 81% specificity for HCC. LR-M provided 79% sensitivity and 97% specificity for non-HCC (ICCA and cHCC-CCA); and the sensitivity and accuracy were lower in differentiating HCC from non-HCC (tumor size <20 mm). LI-RADS v2018 category 5 and M reliably differentiated HBV-related HCC from ICCA. However, a substantial proportion of cHCC-CCAs were categorized LR-5 rather than LR-M. While management is controversial for these combined tumors, accurate prospective differentiation is desired for optimal treatment.
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http://dx.doi.org/10.17305/bjbms.2019.4576DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7416181PMC
August 2020

Derivation and Internal Validation of a Clinical Prediction Tool to Predict Nonalcoholic Fatty Liver Disease in Patients With Crohn's Disease.

Inflamm Bowel Dis 2020 Nov;26(12):1917-1925

Division of Gastroenterology, Washington University in Saint Louis, St. Louis, Missouri, USA.

Background: Crohn's disease (CD) patients have more than double the risk of nonalcoholic fatty liver disease (NAFLD) compared with the general population after considering traditional risk factors. NAFLD remains underappreciated because routine imaging and liver biochemistries are neither sensitive nor specific for the diagnosis. Here we developed a Clinical Prediction Tool for NAFLD in CD (CPN-CD) using readily accessible parameters to diagnose NAFLD, as determined by magnetic resonance proton density fat fraction (PDFF).

Methods: A total of 311 consecutive CD patients who underwent magnetic resonance enterography from June 1, 2017, to May 31, 2018, were screened for NAFLD, defined as a PDFF >5.5% after excluding other liver diagnoses. CPN-CD was derived using binary multivariate logistic regression and internally validated with a 10-fold cross-validation. CPN-CD was compared with the Hepatic Steatosis Index (HSI) by the C-statistic and categorical Net Reclassification Improvement (NRI).

Results: CPN-CD included age, sex, ethnicity/race, serum alanine aminotransferase, body mass index, known cardiometabolic diagnoses, CD duration, and current use of azathioprine/6-mercaptopurine. At <20% risk, NAFLD could be excluded with a sensitivity of 86% (negative predictive value, 86%). At ≥50% risk, NAFLD was diagnosed with a specificity of 87% (positive predictive value, 75%). CPN-CD exhibited good discrimination (C-statistic 0.85) compared with fair discrimination of the HSI (C-statistic, 0.76). CPN-CD was superior to the HSI by net reclassification improvement (+0.20; P < 0.001) and decision curve analysis.

Conclusions: CPN-CD outperforms HSI in detecting NAFLD in patients with CD. Future directions include external validation, outcome validation, and testing generalizability to patients with ulcerative colitis.
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http://dx.doi.org/10.1093/ibd/izz324DOI Listing
November 2020

Assessing Radiology Research on Artificial Intelligence: A Brief Guide for Authors, Reviewers, and Readers-From the Editorial Board.

Radiology 2020 Mar 31;294(3):487-489. Epub 2019 Dec 31.

From the Department of Radiology, University of Wisconsin Madison School of Medicine and Public Health, 600 Highland Dr, Madison, WI 53792 (D.A.B., M.L.S.); Department of Radiology, New York University, New York, NY (L.M.); Department of Musculoskeletal Radiology (M.A.B.) and Institute for Technology Assessment (E.F.H.), Massachusetts General Hospital, Boston, Mass; Department of Medical Imaging, Hospital for Sick Children, University of Toronto, Toronto, Canada (B.B.E.W.); Department of Radiology, University of California-San Diego, San Diego, Calif (K.J.F.); Department of Cancer Imaging, Division of Imaging Sciences & Biomedical Engineering, Kings College London, London, England (V.J.G.); Department of Radiology and Biomedical Imaging, University of California-San Francisco, San Francisco, Calif (C.P.H.); and Department of Radiology and Radiologic Science, The Johns Hopkins University School of Medicine, Baltimore, Md (C.R.W.).

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http://dx.doi.org/10.1148/radiol.2019192515DOI Listing
March 2020

Deep convolutional neural network applied to the liver imaging reporting and data system (LI-RADS) version 2014 category classification: a pilot study.

Abdom Radiol (NY) 2020 01;45(1):24-35

Department of Radiology, Body Imaging Service, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.

Purpose: To develop a deep convolutional neural network (CNN) model to categorize multiphase CT and MRI liver observations using the liver imaging reporting and data system (LI-RADS) (version 2014).

Methods: A pre-existing dataset comprising 314 hepatic observations (163 CT, 151 MRI) with corresponding diameters and LI-RADS categories (LR-1-5) assigned in consensus by two LI-RADS steering committee members was used to develop two CNNs: pre-trained network with an input of triple-phase images (training with transfer learning) and custom-made network with an input of quadruple-phase images (training from scratch). The dataset was randomly split into training, validation, and internal test sets (70:15:15 split). The overall accuracy and area under receiver operating characteristic curve (AUROC) were assessed for categorizing LR-1/2, LR-3, LR-4, and LR-5. External validation was performed for the model with the better performance on the internal test set using two external datasets (EXT-CT and EXT-MR: 68 and 44 observations, respectively).

Results: The transfer learning model outperformed the custom-made model: overall accuracy of 60.4% and AUROCs of 0.85, 0.90, 0.63, 0.82 for LR-1/2, LR-3, LR-4, LR-5, respectively. On EXT-CT, the model had an overall accuracy of 41.2% and AUROCs of 0.70, 0.66, 0.60, 0.76 for LR-1/2, LR-3, LR-4, LR-5, respectively. On EXT-MR, the model had an overall accuracy of 47.7% and AUROCs of 0.88, 0.74, 0.69, 0.79 for LR-1/2, LR-3, LR-4, LR-5, respectively.

Conclusion: Our study shows the feasibility of CNN for assigning LI-RADS categories from a relatively small dataset but highlights the challenges of model development and validation.
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http://dx.doi.org/10.1007/s00261-019-02306-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946904PMC
January 2020

LI-RADS and transplantation: challenges and controversies.

Abdom Radiol (NY) 2021 01;46(1):29-42

Liver Imaging Group, Department of Radiology, University of California, San Diego, CA, USA.

Patients with early stage hepatocellular carcinoma (HCC) can be cured by liver transplantation. HCC imaging features on CT or MRI are specific enough to allow for definitive diagnosis and treatment without the need of confirmatory biopsy. When applied to the appropriate at-risk population the Liver Imaging Reporting and Data System (LI-RADS) imaging criteria achieve high specificity and positive predictive value for the diagnosis of HCC. The Organ Procurement and Transplantation Network (OPTN) is the United States organization that aims to assure the adequate and fair distribution of livers across candidates. Given the importance of fair organ allocation, OPTN also provides stringent imaging criteria for the diagnosis of HCC aiming to avoid false positive diagnosis. Although most imaging criteria are identical for both systems, discrepancies between LI-RADS and the current OPTN classification system for HCC diagnosis exists. Main differences include, but are not limited to, the binary approach of OPTN to classify lesions as HCC or not, versus the probabilistic algorithmic approach of LI-RADS, technical and interpretation considerations, and the approach towards treated lesions. The purpose of this article is to highlight the similarities and discrepancies between LI-RADS and the current OPTN criteria for HCC diagnosis and the implications that these differences may have on the management of patients who are transplant candidates.
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http://dx.doi.org/10.1007/s00261-019-02311-wDOI Listing
January 2021

ACR Appropriateness Criteria® Palpable Abdominal Mass-Suspected Neoplasm.

J Am Coll Radiol 2019 Nov;16(11S):S384-S391

Specialty Chair, Virginia Commonwealth University Medical Center, Richmond, Virginia.

Palpable abdominal masses may arise from the abdominal cavity or the abdominal wall. The differential diagnosis is broad for each variant ranging from benign lipomas, inflammatory processes, to malignant tumors. The imaging approach to diagnosis varies by location. For intra-abdominal masses, contrast-enhanced CT and ultrasound examination have demonstrated accuracy. For abdominal wall masses, which may arise from muscle, subcutaneous tissue, or connective tissue, MRI, CT, and ultrasound all provide diagnostic value. This publication reviews the current evidence supporting the imaging approach to diagnosis of palpable abdominal masses for two variants: suspected intra-abdominal neoplasm and suspected abdominal wall masses. 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.
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http://dx.doi.org/10.1016/j.jacr.2019.05.014DOI Listing
November 2019

Assessment of primary liver carcinomas other than hepatocellular carcinoma (HCC) with LI-RADS v2018: comparison of the LI-RADS target population to patients without LI-RADS-defined HCC risk factors.

Eur Radiol 2020 Feb 25;30(2):996-1007. Epub 2019 Oct 25.

Department of Radiology, University of California San Diego, 200 W Arbor Dr., San Diego, CA, 92103, USA.

Objectives: To determine whether the LI-RADS imaging features of primary liver carcinomas (PLCs) other than hepatocellular carcinoma (non-HCC PLCs) differ between patients considered high risk (RF+) versus not high risk (RF-) for HCC and to compare rates of miscategorization as probable or definite HCC between the RF+ and RF- populations.

Methods: This retrospective study included all pathology-proven non-HCC PLCs imaged with liver-protocol CT or MRI from 2007 to 2017 at two liver transplant centers. Patients were defined per LI-RADS v2018 criteria as RF+ or RF-. Two independent, blinded readers (R1, R2) categorized 265 lesions using LI-RADS v2018. Logistic regression was utilized to assess for differences in imaging feature frequencies between RF+ and RF- patients. Fisher's exact test was used to assess for differences in miscategorization rates.

Results: Non-HCC PLCs were significantly more likely to exhibit nonrim arterial phase hyperenhancement (R1: OR = 2.94; R2: OR = 7.09) and nonperipheral "washout" (R1: OR = 3.65; R2: OR = 7.69) but significantly less likely to exhibit peripheral "washout" (R1: OR = 0.30; R2: OR = 0.10) and delayed central enhancement (R1: OR = 0.18; R2: OR = 0.25) in RF+ patients relative to RF- patients. Consequently, non-HCC PLCs were more often miscategorized as probable or definite HCC in RF+ versus RF- patients (R1: 23.3% vs. 3.6%, p < 0.001; R2: 11.0% vs. 2.6%, p = 0.009).

Conclusions: Non-HCC PLCs are more likely to mimic HCCs on CT and MRI in the LI-RADS target population than in patients without LI-RADS-defined HCC risk factors.

Key Points: • The presence of LI-RADS-defined risk factors for HCC tends to alter the imaging appearances of non-HCC PLCs, resulting in higher frequencies of major features and lower frequencies of LR-M features. • Non-HCC PLCs are more likely to be miscategorized as probable or definite HCC in the LI-RADS target population than in patients without LI-RADS-defined HCC risk factors.
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http://dx.doi.org/10.1007/s00330-019-06448-6DOI Listing
February 2020

Hepatocellular adenomas: Understanding the pathomolecular lexicon, MRI features, terminology, and pitfalls to inform a standardized approach.

J Magn Reson Imaging 2020 06 16;51(6):1630-1640. Epub 2019 Aug 16.

Department of Radiology, University of California San Diego, San Diego, California, USA.

Hepatocellular adenomas (HCAs) are benign hepatic tumors that can be complicated by bleeding and/or malignant transformation. The epidemiology of HCAs has changed over recent decades, primarily influenced by an increased incidence of obesity in both men and women. Currently, at least eight distinct pathomolecular subtypes of HCAs have been identified, several of which have distinguishing and pertinent imaging features on MRI. Emerging evidence suggests that hepatobiliary phase appearance may provide diagnostic and prognostic information. The purpose of this article is to review the current pathomolecular lexicon and imaging features with emphasis on hepatobiliary phase appearance. Level of Evidence: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:1630-1640.
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http://dx.doi.org/10.1002/jmri.26902DOI Listing
June 2020

Liver Imaging Reporting and Data System Version 2018: Impact on Categorization and Hepatocellular Carcinoma Staging.

Liver Transpl 2019 10 9;25(10):1488-1502. Epub 2019 Sep 9.

Liver Imaging Group, Department of Radiology, University of California San Diego, La Jolla, CA.

The purpose of this study was to assess the concordance in categorization and radiologic T staging using Liver Imaging Reporting and Data System (LI-RADS, LR) version 2017 (v2017), version 2018 (v2018), and the Organ Procurement and Transplantation Network (OPTN) criteria. All magnetic resonance imaging and computed tomography reports using a standardized LI-RADS macro between April 2015 and March 2018 were identified retrospectively. The major features (size, arterial phase hyperenhancement, washout, enhancing capsule, or threshold growth) were extracted from the report for each LR-3, LR-4, and LR-5 observation. Each observation was assigned a new category based on LI-RADS v2017, v2018, and OPTN criteria. Radiologic T stage was calculated based on the size and number of LR-5 or OPTN class 5 observations. Categories and T stages assigned by each system were compared descriptively. There were 398 patients (66.6% male; mean age, 63.4 years) with 641 observations (median size, 14 mm) who were included. A total of 73/182 (40.1%) observations categorized LR-4 by LI-RADS v2017 were up-categorized to LR-5 by LI-RADS v2018 due to changes in the LR-5 criteria, and 4/196 (2.0%) observations categorized as LR-5 by LI-RADS v2017 were down-categorized to LR-4 by LI-RADS v2018 due to changes in the threshold growth definition. The T stage was higher by LI-RADS v2018 than LI-RADS v2017 in 49/398 (12.3%) patients. Compared with the OPTN stage, 12/398 (3.0%) patients were upstaged by LI-RADS v2017 and 60/398 (15.1%) by LI-RADS v2018. Of 101 patients, 5 (5.0%) patients with T2 stage based on LI-RADS v2017 and 10/102 (9.8%) patients with T2 stage based on LI-RADS v2018 did not meet the T2 criteria based on the OPTN criteria. Of the 98 patients with a T2 stage based on OPTN criteria, 2 (2.0%) had a T stage ≥3 based on LI-RADS v2017 and 6 (6.1%) had a T stage ≥3 based on LI-RADS v2018.
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http://dx.doi.org/10.1002/lt.25614DOI Listing
October 2019

Reply to "Second-Opinion Consultations: Limitations and Perspectives From a Developing Country".

AJR Am J Roentgenol 2019 08;213(2):W98

2 University of California San Diego, San Diego, CA.

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http://dx.doi.org/10.2214/AJR.19.21457DOI Listing
August 2019

Expanding the Liver Imaging Reporting and Data System (LI-RADS) v2018 diagnostic population: performance and reliability of LI-RADS for distinguishing hepatocellular carcinoma (HCC) from non-HCC primary liver carcinoma in patients who do not meet strict LI-RADS high-risk criteria.

HPB (Oxford) 2019 12 28;21(12):1697-1706. Epub 2019 Jun 28.

Department of Radiology, University of California San Diego, 200 W Arbor Dr., San Diego, CA, 92103, USA.

Background: Hepatocellular carcinoma (HCC) can be diagnosed using imaging criteria in patients at high-risk for HCC, according to Liver Imaging Reporting and Data System (LI-RADS) guidelines. The aim of this study was to determine the diagnostic performance and inter-rater reliability (IRR) of LI-RADS v2018 for differentiating HCC from non-HCC primary liver carcinoma (PLC), in patients who are at increased risk for HCC but not included in the LI-RADS 'high-risk' population.

Methods: This retrospective HIPAA-compliant study included a 10-year experience of pathologically-proven PLC at two liver transplant centers, and included patients with non-cirrhotic hepatitis C infection, non-cirrhotic non-alcoholic fatty liver disease, and fibrosis. Two readers evaluated each lesion and assigned an overall LI-RADS diagnostic category, additionally scoring all major, LR-M, and ancillary features.

Results: The final study cohort consisted of 27 HCCs and 104 non-HCC PLC in 131 patients. The specificity of a 'definite HCC' designation was 97% for reader 1 and 100% for reader 2. The IRR was fair for overall LI-RADS category and substantial for most major features.

Conclusion: In a population at increased risk for HCC but not currently included in the LI-RADS 'high-risk' population, LI-RADS v2018 demonstrated very high specificity for distinguishing pathologically-proven HCC from non-HCC PLC.
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http://dx.doi.org/10.1016/j.hpb.2019.04.007DOI Listing
December 2019

Reply to "Letter to the editor".

Abdom Radiol (NY) 2019 09;44(9):3209

Abdominal Imaging Division, Department of Radiology, University of Pittsburgh, 200 Lothrop street, Pittsburgh, PA, 15213, USA.

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http://dx.doi.org/10.1007/s00261-019-02092-2DOI Listing
September 2019