Blood oxygenation level‐dependent (BOLD) MRI of human skeletal muscle at 1.5 and 3 T

Abstract

Purpose: To evaluate the dependence of skeletal muscle blood oxygenation level-dependent (BOLD) effect and time course characteristics on magnetic field strength in healthy volunteers using an ischemia/reactive hyperemia paradigm.Materials and Methods: Two consecutive skeletal muscle BOLD magnetic resonance imaging (MRI) measurements in eight healthy volunteers were performed on 1.5 T and 3.0 T whole-body MRI scanners. For both measurements a fat-saturated multi-shot multiecho gradient-echo EPI sequence was applied. Temporary vascular occlusion was induced by suprasystolic cuff compression of the thigh. T2* time courses were obtained from two different calf muscles and characterized by typical curve parameters. Ischemia-and hyperemia-induced changes in R2* (DR2*) were calculated for both muscles in each volunteer at the two field strengths.Results: Skeletal muscle BOLD changes are dependent on magnetic field strength as the ratio DR2*(3.0 T)/ DR2*(1.5 T) was found to range between 1.6 and 2.2. Regarding time course characteristics, significantly higher relative T2* changes were found in both muscles at 3.0 T.Conclusion: The present study shows an approximately linear field strength dependence of DR2* in the skeletal muscle in response to ischemia and reactive hyperemia. Using higher magnetic fields is advisable for future BOLD imaging studies of peripheral limb pathologies.

Comparison of Standardized Uptake Values in Normal Structures Between PET/CT and PET/MRI in an Oncology Patient Population

“…Differences between MRI and computed tomography (CT) that are advantageous in certain applications include MRI’s better soft tissue contrast, lack of ionizing radiation, and the ability to perform functional and multi-parametric imaging [2]. Clinical validation of the first PET/MRI systems are currently underway [3] and preliminary case series have recently been published including whole-body oncologic imaging [4, 5] and intracranial tumors [6, 7].…”

Dynamic Blood Oxygen Level-dependent MR Imaging of Muscle: Comparison of Postocclusive Reactive Hyperemia in Young Smokers and Nonsmokers

“…32 However, a recent study using a 3-tesla system showed improved inter-session CVs for BOLD variables, 20 which was presumably attributable to the increased signal-tonoise ratio and BOLD SI contrast with the higher field strength. 22 Our study has several limitations. First, there were few subjects.…”

“…14,16,17,22 We applied a conventional sphygmomanometer air cuff for the thigh (86 © 21 cm; Welch Allyn Japan, Tokyo, Japan) to the middle of the left thigh (Fig. 1a) (40-s rest phase), compressed the cuff by applying pressure of 50 mm Hg above the individual's brachial systolic blood pressure to induce ischemia (300-s ischemic phase), and then rapidly reduced compression by opening the air valve, provoking reactive hyperemia (360-s hyperemic phase) (Fig.…”

“…14,20 Noninvasive techniques are needed for assessing early stage vascular dysfunction, and BOLD MR is potentially such a technique. Dynamic BOLD MR imaging of calf muscle is reportedly useful for assessing microcirculatory function 14,22 and muscle oxygen metabolism 15 during postocclusive reactive hyperemia. However, its usefulness for assessing early stage vascular dysfunction is unclear.…”

Evaluation of blood volume by use of blood oxygen level-dependent magnetic resonance imaging in a cuff-compression model: usefulness of calculated echo time image

“…BOLD MR imaging has also been used to evaluate several extra neural organs, including the heart, kidney, liver, uterus, and skeletal muscle [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. For example, BOLD MR imaging of skeletal muscle has been used to evaluate exercise-induced physiological changes in skeletal muscle [7][8][9] and to assess severity of peripheral arterial occlusive disease [12,13].…”