Blood Oxygen Level Dependent MRI of Normal Kidney and Its Correlation with Physiological Indexes / 天津医药

ABSTRACT

Objective To explore the characteristics of blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) in healthy native kidneys. To investigate the relationship between BOLD-MRI and common physiological in-dexes. Methods GE 3.0T MRI scanner and Torsopa phased-array coil were employed to acquire renal coronal T1WI and BOLD image. Ninety patients who were ruled out chronic kidney diseases underwent BOLD-MRI with T2*-spoiled gradient recalled echo (T2*SPGR) sequence. BOLD images were analyzed on R2*map software. Cortical and medullary R2*values were analyzed in bilateral kidneys and in different gender. Different regional R2*values in cortex and medulla were also ana-lyzed. Physiological indices including age, body height and weight, body mass index (BMI), body surface area (BSA), estimat-ed glomerular filtration rate (eGFR) were recorded. Correlation between R2*value and physiological indices were analyzed. Results Bilateral renal cortical R2*values [left (16.56±1.40) Hz and right (16.66±1.28)Hz, respectively] were less than val-ues in medulla [left (28.82±3.71)Hz and right (28.36±3.72)Hz, respectively]. Female and male cortical R2*values [female (16.55±1.30Hz) and male (16.66±1.38)Hz, respectively] were also less than corresponding values in medulla [female (28.46± 3.64) Hz and male (28.70±3.78) Hz, respectively]. In bilateral renal medullary region, R2*values in low pole (27.29±3.05) Hz was less than values in middle (29.32±3.47) Hz and upper pole (29.16±4.21)Hz (F=15.184, P<0.001). Age was positive-ly correlated with R2* values in medulla (r =0.284, P =0.002). However, eGFR was negatively correlated with medullary R2*value (r=-0.232, P=0.007). Conclusion R2*values reflected the levels of renal partial pressure of oxygen and as-sessed the degree of renal ischemia. BOLD MRI could offer a simple, convenient and noninvasive method for to evaluate renal oxygen metabolism in cortex and medulla.