Abstract
OBJECTIVE To assess the feasibility of blood oxygen level–dependent (BOLD) MRI for measurement of the renal T2* relaxation rate (R2*; proxy for renal oxy-genation) before and after furosemide administration and to evaluate the reliability and repeatability of those measurements in healthy dogs. ANIMALS 8 healthy adult Beagles (4 males and 4 females). PROCEDURES Each dog was anesthetized and underwent BOLD MRI before (baseline) and 3 minutes after administration of furosemide (1 mg/kg, IV) twice, with a 1-week interval between scanning sessions. Mapping software was used to process MRI images and measure R2* and the difference in R2* (∆R2*) before and after furosemide administration. The intraclass correlation coefficient was calculated to assess measurement reliability, and the coefficient of variation and Bland-Altman method were used to assess measurement repeatability. RESULTS Mean ± SD baseline R2* in the renal medulla (24.5 ± 3.8 seconds−1) was significantly greater than that in the renal cortex (20.6 ± 2.7 seconds−1). Mean R2* in the renal cortex (18.6 ± 2.6 seconds−1) and medulla (17.8 ± 1.5 seconds−1) decreased significantly after furosemide administration. Mean ∆R2* in the medulla (6.7 ± 2.4 seconds−1) was significantly greater than that in the renal cortex (2.1 ± 0.7 seconds−1). All R2* and ∆R2* values had good or excellent reliability and repeatability, except the cortical ∆R2*, which had poor repeatability. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that BOLD MRI, when performed before and after furo-semide administration, was noninvasive and highly reliable and repeatable for dynamic evaluation of renal oxygenation in healthy dogs.
Original language | English |
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Pages (from-to) | 880-889 |
Number of pages | 10 |
Journal | American Journal of Veterinary Research |
Volume | 82 |
Issue number | 11 |
DOIs | |
State | Published - 1 Nov 2021 |