Added value of enhanced CT on LR-3 and LR-4 observation of Gd-EOB-DTPA MRI for the diagnosis of HCC: are CT and MR washout features interchangeable?

Objective: To characterize the use of portal venous or delayed phase CT as an alternative to estimate washout for the non-invasive diagnosis of hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced MRI in combination with other features. Methods: This retrospective study included 226 observations (n = 162 patients) at high risk for HCC imaged with gadoxetic acid-enhanced MRI and enhanced liver CT between March 2015 and March 2018. Two radiologists independently evaluated two sets of images and assigned the final Liver Imaging Reporting and Data System (LI-RADS) categories by consensus using gadoxetic acid-enhanced MRI. LR-1, LR-2, LR-5, and LR-M were excluded from the study. The observations were divided using different criteria for washout: hypointensity on the portal venous phase (PVP) at MRI (criteria 1), hypointensity on PVP at MRI and/or hypoattenuation on the PVP/delayed phase at dynamic CT (criteria 2), and hypointensity on the PVP and/or hepatobiliary phase at MRI (criteria 3). The sensitivity, specificity, and accuracy for the diagnosis of HCC were analyzed for each criterion. Results: Using gadoxetic acid-enhanced, 226 lesions were diagnosed as LR-3 or LR-4 by LI-RADS. Among them, 98 and 152 had “washout” at criteria 1 and 2, respectively. For the diagnosis of HCC, criteria 2 and 3 showed significantly higher sensitivities (67.3 and 92.5%, respectively) compared with criteria 1 (35.5%) (p < 0.001). The specificity of criteria 3 (13%) was significantly lower than those of criteria 1 and 2 (40.7% and 38.4%, respectively, p < 0.001). The specificities between criteria 1 and 2 were not statistically different (p = 0.427). Conclusion: Although the LI-RADS lexicon does not permit the interchange of image features among various image modalities, the sensitivity of HCC diagnosis could be improved without any decrease in specificity by adding CT image washout features. Advances in knowledge: Although the LI-RADS lexicon does not permit the interchange of image features among various image modalities, complementary use of dynamic CT in LR-3 or LR-4 categories on the basis of gadoxetic acid-enhanced MRI may contribute to major imaging feature.

18F-Fluorocholine PET and 4D-CT in Patients with Persistent and Recurrent Primary Hyperparathyroidism

Patients with primary hyperparathyroidism (pHPT) can develop persistent (P-pHPT) or recurrent (R-pHPT) disease after parathyroidectomy. Before recommending reoperation, recurrence must be accurately identified because of the high risk of complications. Our study evaluates 18F-fluorocholine (18F-FCH) PET/CT and 4D-CT integrated in PET/4D-CT in patients with P-pHPT/R-pHPT. Patients with P-pHPT/R-pHPT investigated by 18F-FCH PET/4D-CT between May 2018 and March 2021 were retrospectively included. Forty-two patients were included, 37 of whom underwent 4D-CT. The sensitivity and detection rate (DR%) were 95% and 88% for 18F-FCH PET/CT and 70% and 63% for 4D-CT, respectively. PET/CT and 4D-CT were concordant in 18/24 glands and concordant and positive in 15/24 (63%) glands. Discordant results were obtained for 6/24 glands. The surgical success rate was 65%. PET/CT showed significantly higher sensitivity than 4D-CT. Dynamic CT allowed the identification of no additional glands missed by PET/CT, and the combination of the 2 techniques did not improve the sensitivity or DR%. 18F-FCH PET/CT appears to be a valuable technique to accurately detect hyperfunctioning parathyroid tissue in patients with P-pHPT/R-pHPT and is better than 4D-CT. Except for cases with doubtful locations of PET targets that may require 4D-CT for surgical guidance, standard nonenhanced 18F-FCH PET/CT can be effectively recommended in patients with P-pHPT/R-pHPT before reoperation.

Platelet count and abdominal dynamic CT are useful in predicting and screening for gastroesophageal varices after Fontan surgery

Objective Patients who undergo Fontan surgery for complex cardiac anomalies are prone to developing liver and gastrointestinal complications. In particular, gastroesophageal varices (GEVs) can occur, but their prevalence is unknown. We aimed to elucidate the occurrence of GEVs and the predicting parameters of GEVs in these patients. Materials and methods Twenty-seven patients (median age, 14.8 years; median time since surgery, 12.9 years) who had undergone the Fontan surgery and were examined by abdominal dynamic computed tomography (CT) for the routine follow-up were included in the study. Radiological findings including GEVs and extraintestinal complications were retrospectively evaluated by experienced radiologists in a blinded manner. Relationships between blood-biochemical and demographic parameters and the presence of GEVs were statistically analyzed. Results Dynamic CT revealed gastric varices (n = 3, 11.1%), esophageal varices (n = 1, 3.7%), and gastrorenal shunts (n = 5, 18.5%). All patients with gastric varices had gastrorenal shunts. All gastric varices were endoscopically confirmed as being isolated and enlarged, with indications for preventive interventional therapy. A platelet count lower than 119 × 109 /L was identified as a predictor of GEV (area under the receiver operating curve, 0.946; sensitivity, 100%; and specificity, 87%). Conclusions GEVs are important complications that should not be ignored in patients who have undergone a Fontan procedure. Platelet counts lower than 119 × 109 /L may help to prompt patient screening by using abdominal dynamic CT to identify GEVs and their draining collateral veins in these patients.