Evaluation of Renal Oxygenation in Normal Korean Volunteers Using 3.0 T Blood Oxygen Level-Dependent MRI

Purpose : Renal blood oxygen level-dependent (BOLD) MRI has been used in the evaluation of renal oxygenation. We tried to provide the normal R2* value of the human kidney with 3.0 T, and evaluated the differences in R2* values according to gender and location. Materials and Methods: Twenty-four healthy volunteers underwent BOLD MRI at 3.0 T. Multi gradient echo-echo planar imaging sequence with seventeen echoes was used. After generation of the T2* map, the R2* was calculated. The statistical differences in R2* values between the cortex and medulla, males and females, and the right and left kidney were analyzed. The regional differences of R2* within the both kidneys were evaluated respectively. Results: BOLD MRI was successful in all participants. No gross artifact interfered with R2* measurement. The mean R2* at 3.0 T was 17.1 ± 2.60 s in the cortex and 27.7 ± 4.83 s in the medulla (p < 0.001). The R2* value in the medulla was significantly higher in the male than female volunteers (p = 0.025). There were no statistical differences of R2* according to the side and location in the kidney (p = 0.197). Conclusion: Renal BOLD MRI can be efficiently performed with 3.0 T MRI. Renal medullary hypoxia is present in normal volunteers. Our results may be used as reference values in the evaluation of pathologic conditions using BOLD MRI. Index words : Blood oxygen level-dependent MRI∙Kidney∙Normal