Association of LI-RADS and Histopathologic Features with Survival in Patients with Solitary Resected Hepatocellular Carcinoma.

Background Both Liver Imaging Reporting and Data System (LI-RADS) and histopathologic features provide prognostic information in patients with hepatocellular carcinoma (HCC), but whether LI-RADS is independently associated with survival is uncertain. Purpose To assess the association of LI-RADS categories and features with survival outcomes in patients with solitary resected HCC. Materials and Methods This retrospective study included patients with solitary resected HCC from three institutions examined with preoperative contrast-enhanced CT and/or MRI between January 2008 and December 2019. Three independent readers evaluated the LI-RADS version 2018 categories and features. Histopathologic features including World Health Organization tumor grade, microvascular and macrovascular invasion, satellite nodules, and tumor capsule were recorded. Overall survival and disease-free survival were assessed with Cox regression models. Marginal effects of nontargetoid features on survival were estimated using propensity score matching. Results A total of 360 patients (median age, 64 years [IQR, 56-70 years]; 280 male patients) were included. At CT and MRI, the LI-RADS LR-M category was associated with increased risk of recurrence (CT: hazard ratio [HR] = 1.83 [95% CI: 1.26, 2.66], P = .001; MRI: HR = 2.22 [95% CI: 1.56, 3.16], P < .001) and death (CT: HR = 2.47 [95% CI: 1.72, 3.55], P < .001; MRI: HR = 1.80 [95% CI: 1.32, 2.46], P < .001) independently of histopathologic features. The presence of at least one nontargetoid feature was associated with an increased risk of recurrence (CT: HR = 1.80 [95% CI: 1.36, 2.38], P < .001; MRI: HR = 1.93 [95% CI: 1.81, 2.06], P < .001) and death (CT: HR = 1.51 [95% CI: 1.10, 2.07], P < .010) independently of histopathologic features. In matched samples, recurrence was associated with the presence of at least one nontargetoid feature at CT (HR = 2.06 [95% CI: 1.15, 3.66]; P = .02) or MRI (HR = 1.79 [95% CI: 1.01, 3.20]; P = .048). Conclusion In patients with solitary resected HCC, LR-M category and nontargetoid features were negatively associated with survival independently of histopathologic characteristics. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Kartalis and Grigoriadis in this issue.

Applicability of Bosniak 2019 for renal mass classification on portal venous phase at the era of spectral CT imaging using rapid kV-switching dual-energy CT.

OBJECTIVES: To evaluate the applicability of Bosniak 2019 criteria on a monophasic portal venous phase using rapid kilovoltage-switching DECT (rsDECT). MATERIALS AND METHODS: One hundred twenty-seven renal masses assessed on rsDECT were included, classified according to Bosniak 2019 classification using MRI as the reference standard. Using the portal venous phase, virtual monochromatic images at 40, 50, and 77 keV; virtual unenhanced (VUE) images; and iodine map images were reconstructed. Changes in attenuation values between VUE and 40 keV, 50 keV, and 77 keV measurements were computed and respectively defined as ∆HU40keV, ∆HU50keV, and ∆HU77keV. The values of ∆HU40keV, ∆HU50keV, and ∆HU77keV thresholds providing the optimal diagnostic performance for the detection of internal enhancement were determined using Youden index. RESULTS: Population study included 25 solid renal masses (25/127, 20%) and 102 cystic renal masses (102/127, 80%). To differentiate solid to cystic masses, the specificity of the predefined 20 HU threshold reached 88% (95%CI: 82, 93) using ∆HU77keV and 21% (95%CI: 15, 28) using ∆HU40keV. The estimated optimal threshold of attenuation change was 19 HU on ∆HU77keV, 69 HU on ∆HU50eV, and 111 HU on ∆HU40eV. The rsDECT classification was highly similar to that of MRI for solid renal masses (23/25, 92%) and for Bosniak 1 masses (62/66, 94%). However, 2 hyperattenuating Bosniak 2 renal masses (2/26, 8%) were classified as solid renal masses on rsDECT. CONCLUSION: DECT is a promising tool for Bosniak classification particularly to differentiate solid from Bosniak I-II cyst. However, known enhancement thresholds must be adapted especially to the energy level of virtual monochromatic reconstructions. CLINICAL STATEMENT: DECT is a promising tool for Bosniak classification; however, known enhancement thresholds must be adapted according to the types of reconstructions used and especially to the energy level of virtual monochromatic reconstructions. KEY POINTS: • To differentiate solid to cystic renal masses, predefined 20 HU threshold had a poor specificity using 40 keV virtual monochromatic images. • Most of Bosniak 1 masses according to MRI were also classified as Bosniak 1 on rapid kV-switching dual-energy CT (rsDECT). • Bosniak 2 hyperattenuating renal cysts mimicked solid lesion on rsDECT.

Glomerular Filtration Rate Measured Based on Iomeprol Clearance Assessed at CT Urography in Living Kidney Donor Candidates.

Background Estimating glomerular filtration rate (GFR) from serum creatinine can be inaccurate, and current procedures for measuring GFR are time-consuming and cumbersome. Purpose To develop a method for measuring GFR based on iomeprol clearance assessed at CT urography in kidney donor candidates and compare this with iohexol clearance (reference standard for measuring GFR). Materials and Methods This cross-sectional retrospective study included data from kidney donor candidates who underwent both iohexol clearance and CT urography between July 2016 and October 2022. CT-measured GFR was calculated as the iomeprol excretion rate in the urinary system between arterial and excretory phases (Hounsfield units times milliliters per minute) divided by a surrogate for serum iomeprol concentration in the aorta at the midpoint (in Hounsfield units). Performance of CT-measured GFR was assessed with use of mean bias (mean difference between CT-measured GFR and iohexol clearance), precision (the distance between quartile 1 and quartile 3 of the bias [quartile 3 minus quartile 1], with a small value indicating high precision), and accuracy (percentage of CT-measured GFR values falling within 10%, 20%, and 30% of iohexol clearance values). Intraobserver agreement was assessed for 30 randomly selected individuals with the Lin concordance correlation coefficient. Results A total of 75 kidney donor candidates were included (mean age, 51 years ± 13 [SD]; 45 female). The CT-measured GFR was unbiased (1.1 mL/min/1.73 m2 [95% CI: -1.9, 4.1]) and highly precise (16.2 mL/min/1.73 m2 [quartiles 1 to 3, -6.6 to 9.6]). The accuracy of CT-measured GFR within 10%, 20%, and 30% was 61.3% (95% CI: 50.3, 72.4), 88.0% (95% CI: 80.7, 95.4), and 100%, respectively. Concordance between CT-based GFR measurements taken 2 months apart was almost perfect (correlation coefficient, 0.99 [95% CI: 0.98, 0.99]). Conclusion In living kidney donors, GFR measured based on iomeprol clearance assessed at CT urography showed good agreement with GFR measured based on iohexol clearance. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Davenport in this issue.

Sonic hedgehog hepatocellular adenoma: magnetic resonance imaging features and correlation with histology.

OBJECTIVES: Sonic hedgehog hepatocellular adenoma (shHCA) is a new hepatocellular adenoma (HCA) subgroup characterized by high risk of hemorrhage. ShHCA account for below 10% of all HCA cases and are often associated with female gender, obesity, and non-alcoholic steatohepatitis. No specific MRI characteristics have been described to date. The objective of this study was to assess the value of using MRI to identify shHCA, and correlate MRI findings with histology. METHODS: We retrospectively collected MRI scans of 29 patients with shHCA from our center and from different liver referral centers to include 35 lesions. Diagnosis of shHCA was assessed by immunohistochemical overexpression of argininosuccinate synthase 1 or prostaglandin D2 synthase, then confirmed by molecular analysis of sonic hedgehog pathway activation and/or by proteomic analysis. RESULTS: In 46% (n = 16/35) of shHCA cases, we detected intralesional fluid-filled cavities defined on MR images as fluid-like foci markedly hyperintense on T2-weighted sequences, and hypointense on T1-weighted sequences, with or without delayed enhancement. Pathologically, these cavities were observed in 54% of cases as vacuoles filled with blood at different stages of degradation. Hemorrhage and/or necrosis were detected among 71% of cases by MRI analysis (n = 25/35) versus 82% pathologically. Seventeen percent of shHCA cases (n = 6/35) were completely homogeneous via MRI and pathological analysis. No MRI criteria was found in favor of focal nodular hyperplasia, HNF1A-mutated HCA, or typical inflammatory HCA. CONCLUSION: We reveal the presence of intralesional fluid-filled cavities among 46% of our shHCA cases that represent a new MRI finding possibly helpful for shHCA diagnosis. CLINICAL RELEVANCE STATEMENT: This multicenter study is the first clinical study about the radiological aspect of this new hepatocellular adenoma subgroup. This highlights a strong correlation between MRI and histological analysis, with a specific pattern emerging for diagnosis. KEY POINTS: • Sonic hedgehog hepatocellular adenoma is a new hepatocellular adenoma subgroup associated with high risk of hemorrhage, but imaging features of this subgroup remain unknown. • Analysis of MR images and correlation with pathology revealed intralesional fluid-filled cavities and necrotic-hemorrhagic changes. • Intralesional fluid-filled cavities have not yet been described in other adenoma subtypes and represent a new MRI finding for sonic hedgehog hepatocellular adenoma.

The liver in sickle cell disease.

Liver involvement in SCD patients is frequent but often misdiagnosed or underestimated, except in case of advanced liver diseases. Because of so far poorly recognized forms of chronic SCD-related vascular injury that can silently evolved towards end stages or facilitate ACLF, any persisting liver function tests abnormalities should be carefully investigated, following the above proposed algorithm. Work up and management must be considered multidisciplinary in relationship with a Hepatologist. Early SCD hepatopathy should prompt revision of SCD management to prevent further liver injury and decompensation, discussing transfusion exchanges and hydro urea when not yet initiated, and control for any cofactor of liver injury. The role of HSCT in early SCD hepatopathies also deserves evaluation. In advanced SCD hepatopathies, liver transplantation, which has been rarely performed so far, is the only therapeutic option associated with improved survival. It should definitely be discussed- either electively in case of decompensation in SCD cirrhosis or jaundice/recurrent cholangitis in cholestatic diseases, with excellent outcome, - or emergently in case of ALF or ACLF with more mitigate results. To improve knowledge and management of SCD liver diseases, creation of national and international registries, as well as longitudinal observational cohorts are encouraged.

Automated CT LI-RADS v2018 scoring of liver observations using machine learning: A multivendor, multicentre retrospective study.

Background & Aims: Assessment of computed tomography (CT)/magnetic resonance imaging Liver Imaging Reporting and Data System (LI-RADS) v2018 major features leads to substantial inter-reader variability and potential decrease in hepatocellular carcinoma diagnostic accuracy. We assessed the performance and added-value of a machine learning (ML)-based algorithm in assessing CT LI-RADS major features and categorisation of liver observations compared with qualitative assessment performed by a panel of radiologists. Methods: High-risk patients as per LI-RADS v2018 with pathologically proven liver lesions who underwent multiphase contrast-enhanced CT at diagnosis between January 2015 and March 2019 in seven centres in five countries were retrospectively included and randomly divided into a training set (n = 84 lesions) and a test set (n = 345 lesions). An ML algorithm was trained to classify non-rim arterial phase hyperenhancement, washout, and enhancing capsule as present, absent, or of uncertain presence. LI-RADS major features and categories were compared with qualitative assessment of two independent readers. The performance of a sequential use of the ML algorithm and independent readers were also evaluated in a triage and an add-on scenario in LR-3/4 lesions. The combined evaluation of three other senior readers was used as reference standard. Results: A total of 318 patients bearing 429 lesions were included. Sensitivity and specificity for LR-5 in the test set were 0.67 (95% CI, 0.62-0.72) and 0.91 (95% CI, 0.87-0.96) respectively, with 242 (70.1%) lesions accurately categorised. Using the ML algorithm in a triage scenario improved the overall performance for LR-5. (0.86 and 0.93 sensitivity, 0.82 and 0.76 specificity, 78% and 82.3% accuracy for the two independent readers). Conclusions: Quantitative assessment of CT LI-RADS v2018 major features is feasible and diagnoses LR-5 observations with high performance especially in combination with the radiologist's visual analysis in patients at high-risk for HCC. Impact and implications: Assessment of CT/MRI LI-RADS v2018 major features leads to substantial inter-reader variability and potential decrease in hepatocellular carcinoma diagnostic accuracy. Rather than replacing radiologists, our results highlight the potential benefit from the radiologist-artificial intelligence interaction in improving focal liver lesions characterisation by using the developed algorithm as a triage tool to the radiologist's visual analysis. Such an AI-enriched diagnostic pathway may help standardise and improve the quality of analysis of liver lesions in patients at high risk for HCC, especially in non-expert centres in liver imaging. It may also impact the clinical decision-making and guide the clinician in identifying the lesions to be biopsied, for instance in patients with multiple liver focal lesions.

Evaluation of the contribution of shotgun metagenomics in the microbiological diagnosis of liver abscesses.

BACKGROUND: Shotgun metagenomics (SMg) sequencing has gained a considerable interest, as it enables the detection of any microorganisms through a single analysis. Due to the limitations of standard microbiological approaches, the microbial documentation of liver abscesses (LA), which is crucial for their medical management, can be difficult. Here we aimed to compare the performance of SMg with standard approaches for the microbiological documentation of LA. METHODS: In this retrospective study conducted at two centers, we compared the results of standard microbiology with metagenomics analysis of consecutive LA samples. For samples tested positive for Klebsiella pneumoniae, we compared the analysis of virulence and resistance genes using metagenomics data to whole-genome sequencing of corresponding isolates obtained in culture. RESULTS: Out of the 62 samples included, standard approaches and SMg yielded documentation in 80.6% and 96.8%, respectively. In 37.1% (23/62) of cases, both methods showed identical results, whereas in 43.5% (27/62) of cases, the samples were positive by both methods, but SMg found additional species in 88.9% (24/27), mostly anaerobes. When the standard approaches were negative, the SMg was able to detect microorganisms in 80.0% of cases (8/10). Overall, SMg identified significantly more microorganisms than culture (414 vs.105; p<0.05). K. pneumoniae genome analysis was able to detect resistance and virulence genes with a level of sensitivity depending on the depth of sequencing. DISCUSSION: Overall, we showed that SMg had better performance in detecting and identifying microorganisms from LA samples and could help characterizing strain's resistome and virulome. Although still costly and requiring specific skills and expensive equipment, MGs methods are set to expand in the future.

MRI features associated with HCC histologic subtypes: a western American and European bicenter study.

OBJECTIVES: To evaluate if preoperative MRI can predict the most frequent HCC subtypes in North American and European patients treated with surgical resection. METHODS: A total of 119 HCCs in 97 patients were included in the North American group and 191 HCCs in 176 patients were included in the European group. Lesion subtyping was based on morphologic features and immuno-histopathological analysis. Two radiologists reviewed preoperative MRI and evaluated the presence of imaging features including LI-RADS major and ancillary features to identify clinical, biologic, and imaging features associated with the main HCC subtypes. RESULTS: Sixty-four percent of HCCs were conventional. The most frequent subtypes were macrotrabecular-massive (MTM-15%) and steatohepatitic (13%). Necrosis (OR = 3.32; 95% CI: 1.39, 7.89; p = .0064) and observation size (OR = 1.011; 95% CI: 1.0022, 1.019; p = .014) were independent predictors of MTM-HCC. Fat in mass (OR = 15.07; 95% CI: 6.57, 34.57; p < .0001), tumor size (OR = 0.97; 95% CI: 0.96, 0.99; p = .0037), and absence of chronic HCV infection (OR = 0.24; 95% CI: 0.084, 0.67; p = .0068) were independent predictors of steatohepatitic HCC. Independent predictors of conventional HCCs were viral C hepatitis (OR = 3.20; 95% CI: 1.62, 6.34; p = .0008), absence of fat (OR = 0.25; 95% CI: 0.12, 0.52; p = .0002), absence of tumor in vein (OR = 0.34; 95% CI: 0.13, 0.84; p = .020), and higher tumor-to-liver ADC ratio (OR = 1.96; 95% CI: 1.14, 3.35; p = .014) CONCLUSION: MRI is useful in predicting the most frequent HCC subtypes even in cohorts with different distributions of liver disease etiologies and tumor subtypes which might have future treatment and management implications. KEY POINTS: • Representation of both liver disease etiologies and HCC subtypes differed between the North American and European cohorts of patients. • Retrospective two-center study showed that liver MRI is useful in predicting the most frequent HCC subtypes.

Change in Density Not Size of Esophageal Adenocarcinoma During Neoadjuvant Chemotherapy Is Associated with Improved Survival Outcomes.

BACKGROUND: Changes in the size and density of esophageal malignancy during neoadjuvant chemotherapy (NCT) may be useful in predicting overall survival (OS). The aim of this study was to explore this relationship in patients with adenocarcinoma. METHODS: A retrospective single-centre cohort study was performed. Consecutive patients with esophageal adenocarcinoma who received NCT followed by en bloc resection with curative intent were identified. Pre- and post-NCT computed tomography scans were reviewed. The percentage difference between the greatest tumor diameter, esophageal wall thickness and tumor density was calculated. Multivariate Cox regression analysis identified variables independently associated with OS. A ROC analysis was performed on radiological markers to identify optimal cut-off points with Kaplan-Meier plots subsequently created. RESULTS: Of the 167 identified, 88 (51.5%) had disease of the gastro-esophageal junction and 149 (89.2%) were clinical T3. In total, 122 (73.1%) had node-positive disease. Increased tumor density (HR 1.01 per % change, 95% CI 1.00-1.02, p = 0.007), lymphovascular invasion (HR 3.23, 95% CI 1.34-7.52, p = 0.006) and perineural invasion (HR 2.51, 95% CI 1.03-6.08, p = 0.048) were independently associated with a decrease in OS. Patients who had a decrease in their tumor density during the time they received NCT of ≥ 20% in Hounsfield units had significantly longer OS than those who did not (75.5 months versus 34.4 months, 95% CI 38.83-105.13/18.63-35.07, p = 0.025). CONCLUSIONS: Interval changes in the density, not size, of esophageal adenocarcinoma during the time that NCT are independently associated with OS.

Focal Benign Liver Lesions and Their Diagnostic Pitfalls.

Focal hepatic lesions are frequently discovered incidentally on cross-sectional imaging or abdominal ultrasound, and in the general population, a vast majority of those incidental findings are benign entities. However, the formal diagnosis of benign liver lesions is not always straightforward and may require advanced imaging modalities, such as MRI with hepatobiliary contrast agent or contrast-enhanced ultrasound (CEUS). This review presents the typical features of the main benign liver lesions, including focal nodular hyperplasia (FNH), hepatocellular adenoma (HCA), hepatic cysts, hemangioma, angiomyolipoma, and pseudotumors, such as inflammatory pseudotumors or hepatic granulomas. However, beyond the specific and classical MRI features, some lesions may present atypical patterns. Moreover, arterial phase hyperenhancement, often present in benign liver lesions, can be seen in malignant lesions such as hepatocellular carcinoma. Hence, accurate analysis of clinical and biological contexts is mandatory to optimize our diagnostic performance. The objective of this investigation was, therefore, to review the specific presentations of benign liver tumors and to illustrate their diagnostic pitfalls.

Fat in mass in primary liver lesions: are usual MRI diagnostic criteria of both malignant and benign liver lesions still applicable?

PURPOSE: To evaluate the accuracy of the usual MRI diagnostic patterns of primary liver lesions applied to the diagnosis of pathologically proven fat-containing liver lesions. MATERIALS AND METHODS: This monocentric IRB approved retrospective study included all patients with pathologically proven focal liver lesions and documented intra-tumoral fat on pathology and who underwent preoperative liver MRI for characterization. Both liver morphology and usual lesion MRI features were analyzed and their distribution correlated to the final pathological result (Khi-2 or Fisher exact tests, Student t-test or Mann-Whitney U test, as appropriate). The Sensitivity (Se) and Specificity (Sp) of MRI patterns known to be associated to both Hepatocellular Carcinoma (HCC), Focal Nodular Hyperplasia (FNH), and Hepatocellular Adenoma (HCA) subtypes were evaluated. RESULTS: Between March 2014 and November 2021, 66 lesions were included, corresponding to: 26 HCC, 32 HCA, 6 FNH and 2 hepatic angiomyolipoma (HAML). All lesions developed on a dysmorphic liver were HCC. A non-rim arterial phase hyperenhancement with a washout and an enhancing capsule had a 98% specificity for HCC diagnosis; A homogeneous dropout of signal on the opposed phase had a sensitivity of 92% and a specificity of 89% for the diagnosis of HNF1alpha inactivated subtype of HCA (HHCA). The FNH pattern was specific at 100% for the diagnosis of FNH with a 40% Se. Finally, the accuracy of inflammatory hepatocellular adenoma (IHCA) pattern had a low 60% Se but a high 89% Sp for IHCA diagnosis. CONCLUSION: Known MRI patterns remain reliable for the accurate diagnosis of primary liver tumors on MRI even in fat-containing lesions.

Fast T2-weighted liver MRI: Image quality and solid focal lesions conspicuity using a deep learning accelerated single breath-hold HASTE fat-suppressed sequence.

PURPOSE: Acceleration of MRI acquisitions and especially of T2-weighted sequences is essential to reduce the duration of MRI examinations but also kinetic artifacts in liver imaging. The purpose of this study was to compare the acquisition time and the image quality of a single-shot fat-suppressed turbo spin-echo (TSE) T2-weighted sequence with deep learning reconstruction (HASTEDL) with that of a fat-suppressed T2-weighted BLADE TSE sequence in patients with focal liver lesions. MATERIALS AND METHODS: Ninety-five patients (52 men, 43 women; mean age: 61 ± 14 [SD]; age range: 28-87 years) with 42 focal liver lesions (17 hepatocellular carcinomas, 10 sarcoidosis lesions, 9 myeloma lesions, 3 liver metastases and 3 focal nodular hyperplasias) who underwent liver MRI at 1.5 T including HASTEDL and BLADE sequences were retrospectively included. Overall image quality, noise level in the liver, lesion conspicuity and sharpness of liver lesion contours were assessed by two independent readers. Liver signal-to-noise ratio (SNR) and lesion contrast-to-noise ratio (CNR) were measured and compared between the two sequences, as well as the mean duration of the sequences (Student t-test or Wilcoxon test for paired data). RESULTS: Median overall quality on HASTEDL images (3; IQR: 3, 3) was significantly greater than that on BLADE images (2; IQR: 1, 3) (P < 0.001). Median noise level in the liver on HASTEDL images (0; IQR: 0, 0.5) was significantly lower than that on BLADE images (1; IQR: 1, 2) (P < 0.001). On HASTEDL images, mean liver SNR (107.3 ± 39.7 [SD]) and mean focal liver lesion CNR (87.0 ± 76.6 [SD]) were significantly greater than those on BLADE images (67.1 ± 23.8 [SD], P < 0.001 and 48.6 ± 43.9 [SD], P = 0.027, respectively). Acquisition time was significantly shorter with the HASTEDL sequence (18 ± [0] s; range: 18-18 s) compared to BLADE sequence (152 ± 47 [SD] s; range: 87-263 s) (P < 0.001). CONCLUSION: By comparison with the BLADE sequence, HASTEDL sequence significantly reduces acquisition time while improving image quality, liver SNR and focal liver lesions CNR.

Abdominal imaging in ICU patients with viral pneumonia: Are findings in COVID-19 patients really different from those observed with non-SARS-CoV-2 viral pneumonia?

Purpose: To evaluate and compare the prevalence and type of abdominal involvements identified on CT scans in COVID-19 critically ill patients to those observed in critically ill patients with non-SARS-CoV-2 viral pneumonia. Methods: Monocentric IRB approved retrospective study comparing all abdominal CT scans performed for patients admitted in the ICU with COVID-19 and those performed in a historical cohort of ICU patients with non-SARS-CoV-2 viral pneumonia. For each patient, gallbladder abnormality, acute pancreatitis signs, acute adrenal infarction, renal infarcts, bowel wall thickening and CT scan signs of bowel ischemia were assessed. Results were then compared between critically ill COVID-19 and non-COVID-19 patients (Chi-2 or Fisher exact tests for categorical data and Student t-test or Mann-Whitney U test for continuous data as appropriate). Results: Ninety-nine COVID-19 patients and 45 non-COVID-19 patients were included.No difference was found between the rate of abnormal findings comparing COVID-19 patients and patients with other viral pneumonia (63/99 [64%] vs 27/45 [61%], p=0.94). Acute pancreatitis signs were more commonly seen in COVID-19 patients but without statistically difference between groups (14/99 [14%] vs 3/45 [6.7%], p=0.31). Bowel wall thickening was slightly more commonly seen in patients with other viral pneumonia (18/99 [18%] vs 11/45 [24%], p=0.52), however ischemic features were observed in higher rate in the COVID-19 group, although without reaching statistically significant differences (7/99 [7.1%] vs 2/45 [4.4%], p=0.75). Conclusion: The rate and severity of abdominal involvement demonstrated by CT in ICU patients hospitalized for COVID-19 although high were not different to that observed in patients with other severe viral pneumoniae.

Utility of Early Posttreatment PET/CT Evaluation Using FDG or 18F-FCH to Predict Response to 90Y Radioembolization in Patients With Hepatocellular Carcinoma.

BACKGROUND. Assessment of hepatocellular carcinoma (HCC) treatment response after transarterial radioembolization (TARE) is challenging, because response by conventional imaging criteria may not become apparent until 6 months after treatment. Though HCC exhibits variable avidity for FDG, some cases of HCC without avidity for FDG show avidity for 18F-fluorocholine (18F-FCH). OBJECTIVE. The purpose of this study was to evaluate the utility of early posttreatment evaluation by PET/CT using FDG or 18F-FCH to predict 6-month treatment response and survival after TARE in patients with HCC. METHODS. This retrospective study included 37 patients (mean age, 67 years; 34 men, three women) with documented HCC treated by TARE who underwent both pre-treatment FDG PET/CT and 18F-FCH PET/CT and early FDG PET/CT and/or 18F-FCH PET/CT 4-8 weeks after treatment; FDG PET/CT and 18F-FCH PET/CT examinations were performed on separate dates. Only one of 73 initially identified potentially eligible patients was excluded because of lack of HCC avidity for both FDG and 18F-FCH. Response assessment by modified RECIST (mRECIST) on multiphase CT or MRI was performed at 1 month and 6 months in 23 patients. Early responses seen on PET/CT and 1-month mRECIST response were assessed as predictors of 6-month mRECIST response. Univariable and multivariable predictors of overall survival (OS) were identified. RESULTS. On pretreatment PET/CT, 28 (76%) patients were FDG-positive (showed visual uptake on FDG PET/CT and tumor-to-normal liver ratio > 1.15), 15 (41%) were FCH-positive (showed visual uptake on 18F-FCH PET/CT), and six (16%) were both FDG-positive and FCH-positive. Twelve of 28 FDG-positive HCCs exhibited early response by FDG PET/CT; seven of 15 FCH-positive HCCs exhibited early response by 18F-FCH PET/CT. Twelve (52%) patients exhibited 6-month mRECIST response. Response seen on early posttreatment PET/CT exhibited 100% (12/12) sensitivity and 100% (11/11) specificity for 6-month mRECIST response, whereas 1-month mRECIST response exhibited 67% (8/12) sensitivity and 100% (11/11) specificity for 6-month mRECIST response. Response seen on early posttreatment PET/CT was a significant independent predictor of OS on univariable (hazard ratio [HR], 0.4; 95% CI, 0.2-0.9; p = .03) and multivariable (HR, 0.2; 95% CI, 0.1-0.8; p = .01) analyses. CONCLUSION. Early evaluation after TARE by PET/CT using FDG or 18F-FCH may pre dict 6-month response and OS in patients with HCC. CLINICAL IMPACT. Early posttreatment evaluation with PET/CT could help more reliably identify true nonresponders after TARE, which in turn could prompt early response-adapted therapeutic management.

Whole-Body Functional MRI and PET/MRI in Multiple Myeloma.

Bone disease is one of the major features of multiple myeloma (MM), and imaging has a pivotal role in both diagnosis and follow-up. Whole-body magnetic resonance imaging (MRI) is recognized as the gold standard for the detection of bone marrow involvement, owing to its high sensitivity. The use of functional MRI sequences further improved the performances of whole-body MRI in the setting of MM. Whole-body diffusion-weighted (DW) MRI is the most attractive functional technique and its systematic implementation in general clinical practice is now recommended by the International Myeloma Working Group. Whole-body dynamic contrast-enhanced (DCE) MRI might provide further information on lesions vascularity and help evaluate response to treatment. Whole Body PET/MRI is an emerging hybrid imaging technique that offers the opportunity to combine information on morphology, fat content of bone marrow, bone marrow cellularity and vascularization, and metabolic activity. Whole-body PET/MRI allows a one-stop-shop examination, including the most sensitive technique for detecting bone marrow involvement, and the most recognized technique for treatment response evaluation. This review aims at providing an overview on the value of whole-body MRI, including DW and DCE MRI, and combined whole-body 18F-FDG PET/MRI in diagnosis, staging, and response evaluation in patients with MM.

Reply to "Intrapatient Comparison of the Hepatobiliary Phase of Gd-BOPTA and Gd-EOB-DTPA in the Differentiation of Hepatocellular Adenoma From Focal Nodular Hyperplasia".

LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3 CONFLICT OF INTEREST: None. FINANCIAL SUPPORT: None. J. Magn. Reson. Imaging 2020;52:1279-1280.

Quantification of hepatic steatosis with ultrasound: promising role of attenuation imaging coefficient in a biopsy-proven cohort.

OBJECTIVES: To prospectively assess the role of the US attenuation imaging coefficient (AC) for the diagnosis and quantification of hepatic steatosis. METHODS: One hundred and one patients underwent liver biopsy and US-AC measurement on the same day. Liver steatosis was graded according to biopsy as absent (S0 < 5%), mild (S1 5-33%), moderate (S2 33-66%), or severe (S3 > 66%); liver fibrosis was graded from F0 to F4. The correlation between AC and steatosis on pathology (%) was calculated using the Pearson correlation coefficient. The Student t or Mann-Whitney U test was used to compare continuous variables and ROC curve analysis was used to assess diagnostic performance of AC in diagnosing steatosis. RESULTS: Overall, 43 (42%), 35 (35%), 12 (12%), and 11 (11%) patients were classified as S0, S1, S2, and S3, respectively. The AC was positively correlated with steatosis as a continuous variable (%) on pathology (r = 0.58, p < 0.01). Patients with steatosis of any grade had a higher AC than those without steatosis (mean 0.77 ± 0.13 vs. 0.63 ± 0.09 dB/cm/MHz, respectively; p < 0.01, AUROC = 0.805). Patients with S2-S3 had a higher AC than patients with S0-1 (0.85 ± 0.11 vs. 0.67 ± 0.11 dB/cm/MHz, respectively; p < 0.01, AUROC = 0.892). AC > 0.69 dB/cm/MHz had a sensitivity and specificity of 76% and 86%, respectively, for diagnosing any grade of steatosis (S1-S3), and AC > 0.72 dB/cm/MHz had a sensitivity and specificity of 96% and 74%, respectively, for diagnosing S2-S3. The presence of advanced fibrosis (F3-F4) did not affect the calculated AC. CONCLUSIONS: The attenuation imaging coefficient is a promising quantitative technique for the non-invasive diagnosis and quantification of hepatic steatosis. KEY POINTS: • Measurement of the attenuation coefficient is achieved with a very high rate of technical success. • We found a significant positive correlation between the attenuation coefficient and the grade of steatosis on pathology. • The attenuation imaging coefficient is a promising quantitative technique for the noninvasive diagnosis and quantification of hepatic steatosis.

Iso- or hyperintensity of hepatocellular adenomas on hepatobiliary phase does not always correspond to hepatospecific contrast-agent uptake: importance for tumor subtyping.

PURPOSE: This study was conducted in order to evaluate if iso- or hyperintensity of HCAs on HBP is systematically related to a high uptake of hepatospecific contrast agent, using a quantitative approach. METHODS: This bicentric retrospective study included all patients with histologically confirmed and subtyped HCA from 2009 to 2017 who underwent MRI with HBP after Gd-BOPTA injection and who showed iso- or hyperintensity on HBP. The signal intensity of tumors on pre- and postcontrast images and the presence of hepatic steatosis were noted. Contrast uptake on HBP was quantified using the liver-to-lesion contrast enhancement ratio (LLCER) and compared between HCA subtypes (Wilcoxon signed-rank test). Categorical variables were compared using chi-square tests. RESULTS: Twenty-four HCAs showed iso- or hyperintensity on HBP, specifically 17 inflammatory (IHCAs) and 7 ß-catenin HCAs (BHCAs). Eighteen HCAs (75%) (17 IHCAs and 1 BHCAs) had a LLCER < 0% (median - 13.6%, group 1), of which 94% were hyperintense on precontrast T1-W images, with background hepatic steatosis. Six HCAs (25%) had LLCER ≥ 0% (median 2.9%, group 2), and all were BHCAs. A LLCER ≥ 1.6% was associated with the diagnosis of BHCA with a sensitivity of 86% and a specificity of 100%. CONCLUSION: In conclusion, iso- or hyperintensity of hepatocellular adenomas on HBP does not necessarily correspond to an increased hepatospecific contrast-agent uptake. In IHCA, tumor hyperintensity on precontrast images and the underlying steatosis likely explain such iso- or hyperintensity, which do show reduced HBP contrast-agent uptake. On the other hand, marked contrast uptake can be observed, especially in BHCA. KEY POINTS: • Iso- or hyperintensity on HBP does not necessarily reflect a high uptake of hepatospecific contrast agent. • Discrepancies between qualitative signal intensity and quantitative hepatospecific contrast uptake can be explained in IHCA by a combination of tumor hyperintensity on precontrast images and underlying hepatic steatosis. • In BHCA, iso- or hyperintensity on HBP does actually correspond to a greater contrast uptake than that of the liver, demonstrated by an increased lesion-to-liver contrast enhancement ratio (LLCER).

Quantitative correlation between uptake of Gd-BOPTA on hepatobiliary phase and tumor molecular features in patients with benign hepatocellular lesions.

PURPOSE: The purpose of our study was to correlate the quantitative analysis of benign hepatocellular tumor uptake on delayed hepatobiliary phase (HBP) imaging with the quantitative level of OATP expression. METHODS: This single-center retrospective study, which took place between September 2009 and March 2015, included 20 consecutive patients with a proven pathologic and immunohistochemical (IHC) diagnosis of FNH or HCA, including quantification of the OATP expression. The patients underwent Gd-BOPTA-enhancement MRI, including an HBP. The analysis of HBP uptake was performed using the liver-to-lesion contrast enhancement ratio (LLCER). Mean LLCER and OATP expressions were compared between FNH and HCA, and the expression of OATP was correlated with the LLCER value. RESULTS: Of the 23 benign hepatocellular tumors, 9 (39%) were FNH and 14 (61%) were HCA, including 6 inflammatory, 2 HNF1a inactivated, 3 ß-catenin-mutated and 3 unclassified HCAs. On HBP, 100% of the FNH appeared hyper- or isointense, and 79% of the adenomas appeared hypointense. The mean OATP expression of FNH (46.67 ± 26.58%) was significantly higher than that of HCA (22.14 ± 30.74%) (p = 0.0273), and the mean LLCER of FNH (10.66 ± 7.403%) was significantly higher than that of HCA (-13.5 ± 12.25%) (p < 0.0001). The mean LLCER of ß-catenin-mutated HCA was significantly higher than that of other HCAs (p = 0.011). Significant correlation was found between the OATP expression and LLCER values (r = 0.661; p = 0.001). CONCLUSION: In benign hepatocellular tumors, the quantitative analysis of hepatobiliary contrast agent uptake on HBP is correlated with the level of OATP expression and could be used as an imaging biomarker of the molecular background of HCA and FNH. KEY POINTS: • Gd-BOPTA uptake on HBP correlates with the OATP level in benign hepatocellular tumors • FNH and ß-catenin-mutated HCA showed an increased lesion-to-liver contrast enhancement ratio (LLCER) • Increased LLCER may be explained by activation of the Wnt ß-catenin pathway.