Four-dimensional flow MRI quantification of pulmonary regurgitation in patients with repaired tetralogy of Fallot: a study on reproducibility and consistency 
	    		
		   		
		   			
		   		
	    	
    	 
    	10.3760/cma.j.issn.1005-1201.2019.09.009
   		
        
        	
        		- VernacularTitle: 四维血流定量测量法洛四联症患者矫正术后肺动脉瓣反流的可重复性与一致性研究 
 
        	
        	
        	
        		- Author:
	        		
		        		
		        		
			        		Shiqin YU
			        		
			        		
			        		
			        			1
			        			
			        		
			        		
			        		
			        		
			        		;
		        		
		        		
		        		
			        		Minjie LU
			        		
			        		;
		        		
		        		
		        		
			        		Gang YIN
			        		
			        		;
		        		
		        		
		        		
			        		Xinling YANG
			        		
			        		;
		        		
		        		
		        		
			        		Chen CUI
			        		
			        		;
		        		
		        		
		        		
			        		Xiuyu CHEN
			        		
			        		;
		        		
		        		
		        		
			        		Shihua ZHAO
			        		
			        		
		        		
		        		
		        		
		        		
		        			
			        		
			        		Author Information
			        		
		        		
		        		
			        		
			        		
			        			1. Department of MR, Fuwai Hospital, National Center for Cardiovascular Diseases of China, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
			        		
		        		
	        		
        		 
        	
        	
        	
        		- Publication Type:Journal Article
 
        	
        	
        		- Keywords:
        			
	        			
	        				
	        				
			        		
				        		Magnetic resonance imaging;
			        		
			        		
			        		
				        		Pulmonary regurgitation;
			        		
			        		
			        		
				        		Tetralogy of Fallot
			        		
			        		
	        			
        			
        		
 
        	
            
            
            	- From:
	            		
	            			Chinese Journal of Radiology
	            		
	            		 2019;53(9):761-766
	            	
            	
 
            
            
            	- CountryChina
 
            
            
            	- Language:Chinese
 
            
            
            	- 
		        	Abstract:
			       	
			       		
				        
				        	 Objective:To investigate the feasibility and consistency of four-dimensional flow (4D flow) quantification of pulmonary regurgitation in patients with repaired Tetralogy of Fallot (ToF) by comparing with conventional two-dimensional flow (2D flow) and echocardiography.
				        	
				        
				        	Methods:Both the 4D flow and 2D flow imaging were acquired with repaired ToF (a total of 21 patients) consecutively on 3.0 T MR scanner from May 2018 to August 2018. Pulmonary flow and regurgitant fraction were measured by a commercial post processing software Circle CVI42. All patients underwent echocardiography within one week after or before MR examination. The inter/intra-observer variability by 2D/4D f1ow and agreement between the two methods were investigated by interclass correlation coefficients (ICC) and Bland-Altman analyses. The agreement between MR and echocardiography were analyzed by weighted Kappa coefficient. The correlation between pulmonary regurgitation and cardiac function was also investigated by Pearson analysis.
				        	
				        
				        	Results:All patients were included and completed the examinations successfully. Both inter-observer and intra-observer agreement by 4D flow for total forward volume (ICC=0.993, 0.996, respectively, P<0.001), total backward volume (ICC=0.994, 0.997, respectively, P<0.001) and regurgitant fraction (ICC=0.968, 0.985, respectively, P<0.001) were good. The total forward volume, total backward volume and regurgitant fraction measured by 2D flow and 4D flow reached a good agreement (ICC=0.954, 0.913,0.721,respectively,P<0.001). The consistency was good for severity of regurgitation measured by 2D flow (weighted Kappa=0.897, P<0.001) and 4D flow (weighted Kappa=0.710, P=0.001) compared with echocardiography. Significant correlation was found among right ventricular cardiac index(r=0.600, P<0.05), right ventricular end-diastolic volume index(r=0.788, P<0.05), right ventricular end-systolic volume index(r=0.683, P<0.05) and left ventricular end-diastolic volume index(r=0.578, P<0.05), left ventricular end-systolic volume index(r=0.687, P<0.05) with regurgitant fraction measured by 2D flow. Regurgitant fraction measured by 4D flow had a significant correlation with right ventricular cardiac index(r=0.606, P<0.05), right ventricular end-diastolic volume index(r=0.685,P<0.05), right ventricular end-systolic volume index(r=0.534, P<0.05) and left ventricular end-diastolic volume index(r=0.459, P<0.05), left ventricular mass index(r=0.633, P<0.05).
				        	
				        
				        	Conclusion:4D flow MRI provides highly reproducible measurements of pulmonary flow on morphology and haemodynamics in patients with repaired ToF compared with 2D flow MRI and echocardiography.