Assessment of renal perfusion and oxygenation in transplant donor-recipient pairs using arterial spin labelling (ASL) and blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI)

Abstract Objectives To evaluate the role of arterial spin labelling (ASL) and blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) in assessment of perfusion and oxygenation in kidney transplant donor-recipient pairs. Subjects and methods This prospective study included 40 kidney transplant recipients (30 males and 10 females) and 40 corresponding donors (8 males and 32 females) and was done in the period from June, 2022 to January, 2024. Donors underwent ASL and BOLD MRI by using 3 Tesla MRI scanner the day prior to kidney donation (baseline), both donor and recipient underwent the same sequences early (7–10 days) after,3 months and 6 months post-transplantation. Demographic data were recorded. ASL value, BOLD values (MR2*, CR2* and MCR) were correlated with laboratory investigations (serum creatinine and estimated glomerular filtration rate) and compared using ROC curve analyses. Results In donors there were no significant changes as regard the ASL mean value immediately after donation (402.08 ± 42.29 ml/min/100gm), 3 months later (402.06 ± 40.96 ml/min/100gm) or 6 months later (400.17 ± 44.13 ml/min/100gm) also the mean value of the CR2* showed no significant changes either immediately after donation ( 17.65 ± 0.23 /s),3 months after (17.64 ± 0.29 /s) or 6 months later ( 17.60 ± 0.32/s) in the remaining kidney. In recipients there was reduction in the cortical perfusion immediately after donation ( 252.41 ± 109.89 ml/min/100gm) and 3 months later ( 253.35 ± 103.41 ml/min/100gm) compared with the mean ASL value of the pre transplanted donor’s kidney ( 394.12 ± 54.0 ml/min/100gm) ( P = 0.001), after 6 months it showed mild increase in its mean value ( 263.52 ± 91.50 ml/min/100gm) but still less than the baseline mean value ( p = 0.001). There was reduction in the immediate post transplantation cortical R2* mean value (16.89 ± 1.49 /s) and 3 months post transplantation (17.02 ± 1.59 /s) p value (0.004) as well as 6 months post transplantation (24.15 ± 1.69/s). There was a significant difference between the mean ASL value of the recipients with impaired function (114 ± 15.06 ml/min/100gm) and of those with good function group (298.55 ± 85.79 ml/min/100gm) p = 0.001, also as regard the CR2* between the impaired function group (17.91 ± 1.88/s) and of normal function group (16.56 ± 1.21 /s) p value (0.012). The diagnostic accuracy, sensitivity and specificity of ASL for assessment of renal function were 90%, 96.7% and 70% respectively, As the regard the BOLD parameters; MR2* diagnostic accuracy was 85%, sensitivity 93.3% and specificity 60%, CR2* diagnostic accuracy was 80%, sensitivity86.7% and specificity 60%, MCR diagnostic accuracy was 57.5%, sensitivity 50% and specificity 80%. Conclusion The ASL and BOLD are efficient noninvasive methods in functional follow up of the donor-recipients pairs kidneys and efficient in early detection of renal impairment.