Benign and malignant focal liver lesions displaying rim arterial phase hyperenhancement on CT and MRI.

Rim arterial phase hyperenhancement is an imaging feature commonly encountered on contrast-enhanced CT and MRI in focal liver lesions. Rim arterial phase hyperenhancement is a subtype of arterial phase hyperenhancement mainly present at the periphery of lesions on the arterial phase. It is caused by a relative arterialization of the periphery compared with the center of the lesion and needs to be differentiated from other patterns of peripheral enhancement, including the peripheral discontinuous nodular enhancement and the corona enhancement. Rim arterial phase hyperenhancement may be a typical or an atypical imaging presentation of many benign and malignant focal liver lesions, challenging the radiologists during imaging interpretation. Benign focal liver lesions that may show rim arterial phase hyperenhancement may have a vascular, infectious, or inflammatory origin. Malignant focal liver lesions displaying rim arterial phase hyperenhancement may have a vascular, hepatocellular, biliary, lymphoid, or secondary origin. The differences in imaging characteristics on contrast-enhanced CT may be subtle, and a multiparametric approach on MRI may be helpful to narrow the list of differentials. This article aims to review the broad spectrum of focal liver lesions that may show rim arterial phase hyperenhancement, using an approach based on the benign and malignant nature of lesions and their histologic origin. CRITICAL RELEVANCE STATEMENT: Rim arterial phase hyperenhancement may be an imaging feature encountered in benign and malignant focal liver lesions and the diagnostic algorithm approach provided in this educational review may guide toward the final diagnosis. KEY POINTS: Several focal liver lesions may demonstrate rim arterial phase hyperenhancement. Rim arterial phase hyperenhancement may occur in vascular, inflammatory, and neoplastic lesions. Rim arterial phase hyperenhancement may challenge radiologists during image interpretation.

Predictors of Survival Without Intestinal Resection after First-Line Endovascular Revascularization in Patients with Acute Arterial Mesenteric Ischemia.

Background Acute arterial mesenteric ischemia requires emergency treatment and is associated with high mortality rate and poor quality of life. Identifying factors associated with survival without intestinal resection (hereafter, intestinal resection-free [IRF] survival) could help in treatment decision-making after first-line endovascular revascularization. Purpose To identify factors associated with 30-day IRF survival in patients with acute arterial mesenteric ischemia whose first-line treatment was endovascular revascularization. Materials and Methods Patients with acute arterial mesenteric ischemia whose first-line treatment was endovascular revascularization because of a low probability of bowel necrosis were included in this single-center retrospective cohort (May 2014 to August 2022). Patient demographics, laboratory values, clinical characteristics at admission, CT scans, angiograms, and endovascular revascularization-related variables were included. The primary end point was 30-day IRF survival, and secondary end points were 3-month, 1-year, and 3-year overall survival. Factors independently associated with 30-day IRF survival were identified with binary logistic regression. Results A total of 117 patients (median age, 70 years [IQR, 60-77]; 53 female, 64 male) were included. Within 30 days after revascularization, 73 of 117 patients (62%) survived without resection, 28 of 117 (24%) survived after resection, 14 of 117 (12%) died without resection, and two of 117 (2%) underwent resection but died. The 30-day IRF survival was 63% (74 of 117). The 3-month, 1-year, and 3-year mortality rate was 18% (21 of 117), 21% (25 of 117), and 27% (32 of 117), respectively. Independent predictors of 30-day IRF survival were persistent bowel enhancement at initial CT (odds ratio [OR], 0.3; 95% CI: 0.2, 0.8; P = .013) and C-reactive protein (CRP) level less than 100 mg/L (OR, 0.3; 95% CI: 0.1, 0.8; P = .002). The 30-day IRF survival was 86%, 61%, 47%, and 23% in patients with both favorable features, persistent bowel enhancement but CRP level greater than 100 mg/L, no bowel enhancement but CRP level less than 100 mg/L, and both unfavorable features, respectively. Conclusion Independent predictors associated with 30-day IRF survival in patients with acute arterial mesenteric ischemia whose first-line treatment was endovascular revascularization were persistent bowel wall enhancement at initial CT and CRP level less than 100 mg/L. © RSNA, 2024 Supplemental material is available for this article.

Adding Short to Left Gastric Artery Embolization for the Treatment of Obesity: Safety and Effectiveness.

PURPOSE: This study assessed the safety and effectiveness of a technical modification that involves adding short gastric artery (SGA) embolization to left gastric artery (LGA) embolization. MATERIAL AND METHODS: This retrospective single-center study analyzed twenty obese patients (median age of 53.5 (30-73)) who were not eligible for bariatric surgery and underwent bariatric embolization with 300-500-µm microspheres in addition to a lifestyle counseling program between March 2021 and July 2022. Eight patients had LGA + SGA embolization, and twelve had LGA embolization alone. The primary outcome measure was total body weight loss (TBWL) at 6 months in the SGA + LGA and the LGA-only cohorts. Safety was assessed, defined as the 30-day adverse events rate according to the SIR classification. RESULTS: The mean 6-month post-embolization TBWL in the SGA + LGA cohort was 7.3 kg (95%CI 2.1-12.4; p = .01) and 4.1 kg (95%CI 0.4-8.6; p = 0.034) in the LGA-only cohort (mean difference - 3.1 kg ± 2.8; 95%CI (- 9.1-2.8); p = .28). The mean 6-month post-embolization TBWL in the entire cohort was 5.3 kg (p < .01). The rate of complications was similar between the two groups. CONCLUSION: Combined SGA and LGA embolization is safe and effective to treat obesity. Larger studies are needed to determine whether SGA + LGA embolization results in more significant weight loss than LGA embolization alone.

Hepatocellular Carcinoma: Optimal Radiological Evaluation before Liver Transplantation.

Liver transplantation (LT) is the recommended curative-intent treatment for patients with early or intermediate-stage hepatocellular carcinoma (HCC) who are ineligible for resection. Imaging plays a central role in staging and for selecting the best LT candidates. This review will discuss recent developments in pre-LT imaging assessment, in particular LT eligibility criteria on imaging, the technical requirements and the diagnostic performance of imaging for the pre-LT diagnosis of HCC including the recent Liver Imaging Reporting and Data System (LI-RADS) criteria, the evaluation of the response to locoregional therapy, as well as the non-invasive prediction of HCC aggressiveness and its impact on the outcome of LT. We will also briefly discuss the role of nuclear medicine in the pre-LT evaluation and the emerging role of artificial intelligence models in patients with HCC.