Quantification of peak blood flow velocity at the cardiac valve and great thoracic vessels by four-dimensional flow and two-dimensional phase-contrast MRI compared with echocardiography: a systematic review and meta-analysis

•4D flow MRI is comparable to Doppler for peak velocity quantification. •4D flow MRI provides improved assessment for peak velocity compared with 2D PC MRI. •Volumetric 4D flow analysis is superior to planar method for velocity quantification. AIM To objectively examine the agreement and correlation between four-dimensional (4D) flow magnetic resonance imaging (MRI) and traditional two-dimensional (2D) phase-contrast (PC) MRI with the reference...