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Objective:
This study aims to evaluate whether 4D flow MRI with quantitative hemodynamic parameters could be used as an add-on tool to endoscopy for predicting actual bleeding in patients with cirrhosis with esophageal varices.

Materials and Methods:
All patients with cirrhosis underwent 4D flow MRI using a 3-T scanner (Skyra; Siemens Healthcare, Erlangen, Germany) covering the abdominal vessels, including the right portal vein (PV), main PV, splenic vein (SV), and superior mesenteric vein (SMV), with the following MR parameters: TR/TE 6.25/3.81 ms, FOV 340 × 380 mm2, matrix 160 × 90, and slice thickness 2.5 mm. The velocity-encoding sensitivity for x, y, and z flow-encoding directions was set to 30, 20, and 20 cm/s, respectively. Finally, a total of 109 patients with cirrhosis with endoscopically confirmed esophageal varices were divided into groups A (negative RC sign with no variceal bleeding, n = 60, age 35–81 years), B (negative RC sign with variceal bleeding, n = 13, age 41–80 years), C (positive RC sign with no variceal bleeding, n = 10, age 49–81 years), and D (positive RC sign with variceal bleeding, n = 26, age 48–81 years). The RC sign was defined to be present when erythrogenic findings were seen on the varices endoscopically, and the presence of variceal bleeding was defined as the occurrence of active bleeding within 1 year after initial diagnosis of esophageal varices, based on the endoscopic and clinical findings. The quantitative parameter of 4D flow MRI included the net flow rate (mL/s), mean flow rate (mL/s), peak flow rate (mL/s), and net forward volume (mL) in each vessel. The 4D flow MR parameters were compared among the groups using Mann-Whitney U test, and ROC curve analysis was performed to evaluate the diagnostic performance.

Results:
The values of all 4D flow MR parameters in the right and main PV of patients with a positive RC sign were significantly lower than those of patients with a negative RC sign (p < 0.05). The patients with variceal bleeding in groups B and D showed lower values in all MR parameters in the main PV compared with patients with no variceal bleeding in group A and C (p < 0.05). However, there were no significant differences among the groups regarding the MR parameters in the SV and SMV. In the ROC analysis for evaluating the diagnostic performance of actual variceal bleeding, AUC values were 0.762 and 0.7700.787 in endoscopy alone and MR alone, respectively. However, in the combination of endoscopy and 4D flow MRI, the AUC value increased significantly to 0.871. When comparing these AUCs, the value of the combination of endoscopy and 4D flow MRI was significantly different from endoscopy alone and MR alone (p < 0.05), and there was no difference between endoscopy alone and MR alone.

Conclusion:
The 4D flow MRI could significantly contribute to improving the diagnostic performance of endoscopy in predicting actual bleeding in patients with cirrhosis and esophageal varices.