Repeatability and sensitivity of high resolution blood volume mapping in mouse kidney disease.

PURPOSE:To evaluate the repeatability of MRI-derived relative blood volume (RBV) measurements in mouse kidneys across subjects and days and to evaluate sensitivity of this approach to renal pathology. MATERIALS AND METHODS:A 7 Tesla MRI system and an intravascular iron-oxide contrast agent were used to acquire spin-echo-based renal RBV maps in 10 healthy mice on 2 consecutive days. Renal RBV maps were also acquired in the Alport and unilateral ureteral obstruction mouse models of renal disease. RESULTS:The average renal RBV measured on consecutive days was 19.97 ± 1.50 and 19.86 ± 1.62, yielding a concordance correlation coefficient of 0.94, indicating that this approach is highly repeatable. In the disease models, the RBV values were regionally dissimilar and substantially lower than those found in control mice. CONCLUSION:In vivo renal iron-oxide-based RBV mapping in mice complements the physiological information obtained from conventional assays of kidney function and could shed new insights into the pathological mechanisms of kidney disease.