Comprehensive evaluation for transplant renal arterial morphology, hemodynamics, and renal function: utilizing...

Assessing the performance of four-dimensional (4D) flow MRI in evaluating transplant renal arterial morphology, hemodynamics, and renal function.

Between August 2023 and May 2024, 104 kidney transplant patients under long-term follow-up and willing to undergo multi-parameter MRI and ultrasound were prospectively enrolled. The performance of 4D flow MRI in evaluating transplant renal arterial morphology, hemodynamics, and renal function was assessed and compared with non-contrast enhanced magnetic resonance angiography (NCE-MRA), doppler ultrasonography (DUS), and estimated glomerular filtration rate (eGFR), respectively.

In total, 91 transplanted kidneys were comprehensively assessed. In the morphological study, the vessel visibility found in 4D flow for the main renal artery showed no significant difference than in NCE-MRA. Correlation was excellent between the stenosis degrees measured with 4D flow and NCE-MRA (r = 0.94; P < 0.05). In the hemodynamic study, the peak systolic velocity (PSV), end diastolic velocity (EDV), and resistive index (RI) measured using 4D flow and DUS in transplant renal artery demonstrated significant correlations (rPSV = 0.58, rEDV = 0.74, rRI = 0.67; all P < 0.001). Compared to DUS (P < 0.05), 4D flow underestimated PSV and EDV by 21.3 and 16.7%. No significant difference in RI was found between 4D flow and DUS (P = 0.714). In the renal functional study, PSV, EDV and RI measured by 4D flow and eGFR exhibited statistically significant correlations (rPSV = 0.40, rEDV = 0.51, rRI = -0.26; all P < 0.05). PSV and EDV have acceptable diagnostic performance in identifying inferior graft function (IGF) (AUCPSV = 0.71, P = 0.0011; AUCEDV = 0.71, P = 0.0014).

The 4D flow MRI is a useful, non-radiation, non-invasive, and non-contrast method that can provide valuable reference information for assessing transplant renal arterial morphology, hemodynamics, and renal function.