Assessment of regional myocardial oxygenation changes in the presence of coronary artery stenosis with balanced SSFP imaging at 3.0T: Theory and experimental evaluation in canines

Abstract

Purpose:To examine the dependence of steady-state freeprecession (SSFP) -based myocardial blood-oxygen-leveldependent (BOLD) contrast on field strength using theoretical and experimental models. Materials and Methods:Numerical simulations using a two-pool exchange model and a surgically prepared dog model were used to assess the SSFP-based myocardial BOLD signal changes at 1.5T and 3.0T. Experimental studies were performed in eight canines with pharmacological vasodilation under various levels of left circumflex coronary artery stenosis. Experimentally obtained BOLD signal changes were correlated against microsphere-based true flow changes. Results:Theoretical results showed that, at 3.0T, relative to 1.5T, a threefold increase in oxygen sensitivity can be expected. Experimental studies in canines showed near similar results-a 2.5 Ϯ 0.2-fold increase in BOLD sensitivity at 3.0T relative to 1.5T (P Ͻ 0.05). Based on the scatter gram of BOLD data and microsphere data, it was found that the minimum regional flow difference that can be detected with SSFP-based myocardial BOLD imaging at 1.5T and 3.0T were 2.9 and 1.6, respectively (P Ͻ 0.05). Conclusion:This study demonstrated that SSFP-based myocardial BOLD sensitivity is substantially greater at 3.0T compared with 1.5T. The findings here suggest that SSFP-based myocardial BOLD imaging at 3.0T may have the necessary sensitivity to detect the clinically required minimum flow difference of 2.0.

Myocardial T2* Mapping with Ultrahigh Field Magnetic Resonance: Physics and Frontier Applications

“…Since microscopic susceptibility increases with field strength, thus making oxygenation sensitivity due to ischemic (patho) physiology more pronounced, T 2 * mapping at 7.0 T might be beneficial to address some of the BOLD sensitivity constraints reported for the assessment of regional myocardial oxygenation changes in the presence of coronary artery stenosis [121] or for the characterization of vasodilator-induced changes of myocardial oxygenation at 1.5 T and at 3.0 T [10].…”

Three-dimensional contrast-enhanced and non-contrast-enhanced cardiac magnetic resonance imaging for the assessment of myocardial ischemic reactions

“…Phantom studies suggested a three-fold increase of myocardial BOLD contrast at 3.0 Tesla in comparison to 1.5 Tesla. 39 In an experimental setting the gain in myocardial BOLD contrast based on a SSFP sequence at 3.0 Tesla reached up to a 2.5-fold signal increase. 39 Favorably, the increase in myocardial BOLD signal using the abovementioned SSFP sequence was observed independently of varying coronary blood flow.…”

Impaired myocardial oxygenation response to stress in patients with chronic kidney disease

“…As recently reviewed, the BOLD CMR technique has been extensively validated in preclinical and clinical studies at both 1.5 and 3 T using a variety of sequences. 35 The SSFP sequence used in this study was initially validated in the canine heart at 1.5 T by Fieno et al 20 We used the higher field strength (3 T) given the limited signal-to-noise ratio between normal and deoxygenated myocardial regions at 1.5 T. 21 The BOLD measurement reproducibility in this study compares favorably with the BOLD SI measurement reproducibility demonstrated by Karamitsos et al, who used the same SSFP sequence at 3 T. 23 Myocardial Oxygenation, Epicardial and Microvascular CAD BOLD CMR technique can identify not only epicardial coronary artery stenosis, but also potentially coronary microvascular dysfunction. BOLD CMR has moderate accuracy in detecting significant CAD.…”

“…11 The transition from diamagnetic oxyhemoglobin to paramagnetic deoxyhemoglobin induces a change in magnetic resonance signal intensity (SI) and thereby generates oxygen-dependent contrast. 12 The BOLD technique has been validated in animal models [13][14][15][16][17][18][19][20][21] and utilized in human studies in patients with angina, CAD, syndrome X, and hypertension. [22][23][24][25][26] We utilized BOLD CMR to measure myocardial oxygenation response to stress in the CKD population as a measure of myocardial ischemia and searched for associations with renal function.…”