Article

Assessment of myocardial blood flow (MBF) in humans using arterial spin labeling (ASL): feasibility and noise analysis.

Ming Hsieh Department of Electrical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California 90089-2564, USA.
Magnetic Resonance in Medicine (Impact Factor: 3.4). 09/2009; 62(4):975-83. DOI: 10.1002/mrm.22088
Source: PubMed

ABSTRACT Arterial spin labeling (ASL) is a powerful tool for the quantitative measurement of tissue blood flow, and has been extensively applied to the brain, lungs, and kidneys. ASL has been recently applied to myocardial blood flow (MBF) measurement in small animals; however, its use in humans is limited by inadequate signal-to-noise ratio (SNR) efficiency and timing restrictions related to cardiac motion. We present preliminary results demonstrating MBF measurement in humans, using cardiac-gated flow-sensitive alternating inversion recovery (FAIR) tagging and balanced steady-state free precession (SSFP) imaging at 3T, and present an analysis of thermal and physiological noise and their impact on MBF measurement error. Measured MBF values in healthy volunteers were 1.36 +/- 0.40 ml/ml/min at rest, matching the published literature based on quantitative (13)N-ammonia positron emission tomography (PET), and increased by 30% and 29% with passive leg elevation and isometric handgrip stress, respectively. With thermal noise alone, MBF can be quantified to within +/- 0.1 ml/ml/min with 85.5% confidence, for 3.09 cm(3) regions averaged over 6 breath-holds. This study demonstrates the feasibility of quantitative assessment of myocardial blood flow in humans using ASL, and identifies SNR improvement and the reduction of physiological noise as key areas for future development.

0 Bookmarks
 · 
187 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: : Background Myocardial arterial spin labeling (ASL) is a noninvasive MRI based technique that is capable of measuring myocardial blood flow (MBF) in humans. It suffers from poor sensitivity to MBF due to high physiological noise (PN). This study aims to determine if the sensitivity of myocardial ASL to MBF can be improved by reducing image acquisition time, via parallel imaging. Methods Myocardial ASL scans were performed in 7 healthy subjects at rest using flow-sensitive alternating inversion recovery (FAIR) tagging and balanced steady state free precession (SSFP) imaging. Sensitivity encoding (SENSE) with a reduction factor of 2 was used to shorten each image acquisition from roughly 300 ms per heartbeat to roughly 150 ms per heartbeat. A paired Student’s t-test was performed to compare measurements of myocardial blood flow (MBF) and physiological noise (PN) from the reference and accelerated methods. Results The measured PN (mean ± standard deviation) was 0.20 ± 0.08 ml/g/min for the reference method and 0.08 ± 0.05 ml/g/min for the accelerated method, corresponding to a 60% reduction. PN measured from the accelerated method was found to be significantly lower than that of the reference method (p = 0.0059). There was no significant difference between MBF measured from the accelerated and reference ASL methods (p = 0.7297). Conclusions In this study, significant PN reduction was achieved by shortening the acquisition window using parallel imaging with no significant impact on the measured MBF. This indicates an improvement in sensitivity to MBF and may also enable the imaging of subjects with higher heart rates and imaging during systole.
    Journal of Cardiovascular Magnetic Resonance 01/2014; 16(1):15. · 4.44 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Rapid magnetic resonance imaging (MRI) of the heart, during the first pass of an injected contrast bolus is routinely used to detect hypoperfused myocardium, both at rest, and during vasodilator stress. Adapting this approach for quantitative perfusion imaging has been successfully tested and validated over more than 15 years in experimental models and clinical studies, yielding quantitative estimates of the perfusion reserve to detect epicardial stenoses and microvascular dysfunction, and to quantify absolute myocardial blood flow (in mL/minute/g of myocardial tissue). This review presents an overview of the most common approaches used in contrast-enhanced cardiac MRI for quantification of myocardial perfusion, and identifies some critical areas of current research. In its present state, cardiac MRI is a viable, diagnostically valuable alternative to other cardiac imaging modalities for the quantification of myocardial perfusion.
    Current Cardiovascular Imaging Reports 06/2012; 5(3).
  • [Show abstract] [Hide abstract]
    ABSTRACT: This review is intended to give a comprehensive overview over new cardiovascular magnetic resonance (CMR) method developments and refinements dedicated to the fully non-invasive in vivo exploration of the rodent heart. Unlike other cardiovascular imaging techniques, CMR techniques exist in many modalities giving access to parameters characterizing morphology, global and regional function, blood flow, myocardial structure, cell damage, metabolism and other molecular processes in mouse and rat models of human disease. But even in healthy animals, small animal CMR techniques can help exploring general physiological and biochemical mechanisms in vivo. New magnetic resonance imaging methods and imaging protocols are actively being developed by the entire CMR community with the goal of widening the spectrum of observable and measurable myocardial properties. This report also includes a selection of application studies using recent CMR methodology in this field. Beyond giving new insights into pathophysiologic processes, these studies underline the growing usefulness of CMR in a small animal research context.
    Current Cardiovascular Imaging Reports 02/2014; 7(2).

Full-text (2 Sources)

Download
80 Downloads
Available from
Jun 10, 2014