Total Bilirubin Level as a Predictor of Suboptimal Image Quality of the Hepatobiliary Phase of Gadoxetic Acid-Enhanced MRI in Patients with Extrahepatic Bile Duct Cancer

Imaging cholangiocarcinoma: CT and MRI techniques

Cross-sectional imaging plays a crucial role in the detection, diagnosis, staging, and resectability assessment of intra- and extrahepatic cholangiocarcinoma. Despite this vital function, there is a lack of standardized CT and MRI protocol recommendations for imaging cholangiocarcinoma, with substantial differences in image acquisition across institutions and vendor platforms. In this review, we present standardized strategies for the optimal imaging assessment of cholangiocarcinoma including contrast media considerations, patient preparation recommendations, optimal contrast timing, and representative CT and MRI protocols with individual sequence optimization recommendations. Our recommendations are supported by expert opinion from members of the Society of Abdominal Radiology's Disease-Focused Panel (DFP) on Cholangiocarcinoma, encompassing a broad array of institutions and practice patterns.

Suboptimal hepatobiliary phase image in gadoxetic acid-enhanced liver MRI for the evaluation of the HCC: Predictive factors

To determine the relevant laboratory values for hepatobiliary phase (HBP) imaging and predictive factors for suboptimal HBP images on gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) for the evaluation of hepatocellular carcinoma (HCC) in patients with chronic liver disease (CLD). This study included 307 patients with CLD who underwent gadoxetic acid-enhanced liver MRI for HCC evaluation. The liver-portal vein contrast ratio and liver-spleen contrast ratio were calculated from the measurements of the HBP images. In this study, a suboptimal HBP image was defined as the presence of a bright portal vein or a liver-spleen contrast ratio of <1.5. Correlation, comparison, and receiver operating characteristic analyses were performed between the measured parameters on the HBP images and hepatic and renal function tests. The estimated glomerular filtration rate did not correlate with any measured or calculated values on the HBP images. On receiver operating characteristic analysis, the optimal cutoff value for the bright portal vein was an albumin level of 4.05 g/dL (area under the curve, 0.971; sensitivity, 65%; specificity, 82%). The optimal cutoff value of the suboptimal HBP image was a serum direct bilirubin level of 0.83 mg/dL (area under the curve, 0.830; sensitivity, 69%; specificity, 84%). On gadoxetic acid-enhanced MRI for the evaluation of HCC in patients with CLD, suboptimal HBP images were most strongly correlated with serum direct bilirubin levels. Renal function was not associated with suboptimal HBP imaging. Although the sensitivity is low, suboptimal HBP images can be predicted before gadoxetic acid-enhanced liver MRI can be performed.

Inter-reader reliability of functional liver imaging score derived from gadoxetic acid-enhanced MRI: a meta-analysis

PURPOSE

This study aimed to systematically determine the inter-reader reliability of the functional liver imaging score (FLIS) and explore the factors affecting it.

METHODS

Original articles reporting the inter-reader reliability of FLIS derived from gadoxetic acid-enhanced magnetic resonance imaging (MRI) were systematically searched in the MEDLINE and EMBASE databases from January 2013 to June 2022. Data synthesis was performed to calculate the meta-analytic pooled estimates of the FLIS and its three subcategories, including enhancement quality score (EnQS), excretion quality score (ExQS), and portal vein sign quality score (PVsQS) using the DerSimonian-Laird random-effects model. To explore any cause of study heterogeneity, we conducted a meta-regression analysis.

RESULTS

Six studies with data from 1419 patients were included. The meta-analytic pooled inter-reader reliability of FLIS was 0.93 (95% confidence interval [CI], 0.88-0.98). That of the three FLIS subcategories were 0.93 (95% CI, 0.85-1.00), 0.95 (95% CI, 0.91-1.00), and 0.90 (95% CI, 0.81-0.99) for EnQS, ExQS, and PVsQS, respectively. The pooled FLIS data was moderately heterogenous, but heterogeneity was not associated with the study methodology, MRI-related factors, and reader experience.

CONCLUSION

The FLIS and its three subcategories showed almost perfect inter-reader reliability. Therefore, FLIS may be a reliable imaging parameter that reflects liver function and outcomes in patients with chronic liver disease. Further studies should be conducted to confirm any factors affecting the inter-reader reliability of FLIS.

Comprehensive Imaging Review of Pleural Fistulas from Diagnosis to Management

Pleural fistula is an abnormal communication between the pleural cavity and an adjacent structure. The interplay of anatomic and physiologic factors including proximity to various intrathoracic structures, deep pleural recesses, and negative pleural pressures makes the pleura an easy victim of fistulization. Iatrogenic creation followed by necrotizing infections and malignancies are the most common causes. While the overall incidence and size of postsurgical pleural fistulas are decreasing with increased adoption of vascularized flaps for high-risk resections, the smaller fistulas that develop in the setting of post-radiation therapy changes, with necrotizing infections in immunosuppressed patients, and with use of newer antiangiogenic chemotherapies can be challenging to visualize directly. Imaging signs in clinical practice are often subtle and indirect. Multimodality imaging and biochemical pleural fluid analysis can offer important adjunctive information when a diagnosis is only suggested with the first imaging study. Certain pleural fistulas are inconsequential, some spontaneously close with or without diversion of flow or use of positive-pressure ventilation, while others carry a higher risk of complications or recurrence. Estimated fistula size, factors that impair healing, and the possibility of diversion are important considerations when deciding between endoscopic or surgical closure. The authors have tailored this article for a general imager or clinical practitioner and review 10 types of pleural fistulas, ranging from routine to rare, with regard to their etiology, pathophysiology, clinical cues, imaging features, nuances of pleural fluid analysis, and management options available today. ^©RSNA, 2022.