Non invasive quantification of coronary endothelial function using 3 T MRI
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KeywordsMyocardial Blood Flow Coronary Blood Flow Cold Pressor Test Coronary Vascular Resistance Coronary Vasomotor
Endothelial dysfunction (ED) plays a key role in the development of cardiovascular disease; a non invasive MRI method of quantification of coronary ED would be relevant for risk stratification, treatment, monitoring and prognosis evaluation in several diseases involving ED.
To evaluate the feasibility of assessing coronary endothelial function by myocardial blood flow (MBF) measurement using coronary sinus flow quantification [1, 2] at rest and during cold pressor test (CPT), which is used in nuclear medicine to assess endothelium-dependent coronary vasomotor function.
Materials and methods
Thirteen healthy volunteers (ten men, three women) without any coronary risk factors underwent magnetic resonance imaging in a 3 T scanner (Verio, Siemens, Erlangen, Germany). CPT was performed by immersing the right ankle in ice-water during four minutes. Heart rate and blood pressure were monitored throughout the protocol using a Maglife system (Schiller). Coronary sinus flow was measured at rest and during CPT using non breath-hold velocity encoded phase contrast cine MRI (repetition time/echo time: 45 ms/2 ms, slice thickness: 5.5 mm, field of view: 250 × 250 mm2, averages: 11, matrix: 256 × 256, flow encoding: 70 cm/sec, flip angle: 25°, acquisition time: 4 minutes, GRAPPA k-space reduction factor: 4). Myocardial function and morphology were evaluated using SSFP sequence. MBF was calculated combining coronary sinus flow quantification and morphologic data using Argus software (flow and 2D). Coronary endothelial function was assessed by comparing MBF at rest and during CPT. Coronary vascular resistance (CVR) and endothelium-dependent vasodilation index (EDVI) were calculated.
MRI coronary sinus flow quantification as a measure of the myocardial blood flow without contrast agent allows to detect significant changes in response to CPT in healthy volunteers. This non invasive measure may help to detect changes in endothelial function which occur early in a variety of cardiovascular diseases.
This article is published under license to BioMed Central Ltd.