Measurement of renal tissue oxygenation with Blood Oxygen Level Dependent (BOLD) MRI and oxygen transit modeling.

Measurement of renal tissue oxygenation with Blood Oxygen Level Dependent (BOLD) MRI and oxygen transit modeling. Am J Physiol Renal Physiol. 2014 Jan 22; Authors: Zhang JL, Morrell G, Rusinek H, Warner L, Vivier PH, Cheung AK, Lerman LO, Lee VS Abstract Blood oxygen level dependent (BOLD) MRI data of kidney, while indicative of tissue oxygenation level (pO2), is in fact influenced by multiple confounding factors, such as R2, perfusion, oxygen permeability, and hematocrit. We aim to explore the feasibility of extracting tissue pO2 from renal BOLD data. A method of two steps was proposed: first, a Monte Carlo simulation to estimate blood oxygen saturation (SHb) from BOLD signals and second, an oxygen transit model to convert SHb to tissue pO2. The proposed method was calibrated and validated with 20 pigs (12 before and after furosemide injection) in which BOLD-derived tissue pO2 was compared to microprobe-measured values. The method was then applied to 9 healthy human subjects (age 25.7±3.0 yrs) in whom BOLD was performed before and after furosemide. For the 12 pigs before furosemide injection, the proposed model estimated renal tissue pO2 with errors of 2.3±5.2 mmHg (5.8%±13.4%) in cortex and -0.1±4.5 mmHg (1.7%±18.1%) in medulla, compared with microprobe measurements. After injection of furosemide, the estimation errors were 6.9±3.9 mmHg (14.2%±8.4%) for cortex and 2.6±4.0 mmHg (7.7%±11.5%) for medulla. In the human subjects, BOLD-de...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research