"Blood flow assessment using 4D flow MRI has helped the understanding of many physiopathological issues in the follow-up of patients with complex grown-up congenital heart disease," Dr. Arshid Azarine from Saint Joseph Hospital in Paris told AuntMinnie.com.
However, 4D flow MRI sequences are currently based on a single predefined velocity encoding, which is a parameter that clinicians use to determine specific ranges for blood flow velocity in a particular vessel, Azarine continued. This approach restricts 4D flow MRI analysis to a narrow window of blood flow velocity, often requiring clinicians to perform multiple MRI sequences to obtain a more comprehensive assessment of blood flow.
In their study, the researchers from France explored the feasibility of performing 4D flow MRI using two different velocity encodings in a single scan. They tested this dual-velocity encoding strategy on 10 young adults who had undergone surgery for complex CHD and required follow-up imaging.
The patients underwent gadolinium-enhanced cardiac MRI followed by a dual-velocity encoding 4D flow MRI sequence, with a high-velocity encoding set at 300 cm/sec and a low-velocity encoding at 100 cm/sec. It took roughly 12 minutes to complete the scan.
Analysis of the data revealed that the dual-velocity method reliably incorporated the low- and high-velocity fields, generating accurate velocity measurements for the vena cava. Dual-velocity 4D flow MRI provided high- and low-velocity measurements simultaneously, completing in one scan what the standard approach required two scans to do -- ultimately reducing acquisition time for this task by approximately 25%.
