Volume 13 Supplement 1

Abstracts of the 2011 SCMR/Euro CMR Joint Scientific Sessions

Open Access

Arterial spin labeled MRI detects clinically relevant increases in myocardial blood flow with vasodilatation

  • Zungho Zun1,
  • Padmini Varadarajan2,
  • Ramdas G Pai2,
  • Eric C Wong3 and
  • Krishna S Nayak1
Journal of Cardiovascular Magnetic Resonance201113(Suppl 1):O94

DOI: 10.1186/1532-429X-13-S1-O94

Published: 2 February 2011

Objective

This study sought to demonstrate the potential for arterial spin labeling (ASL) to differentiate normal and ischemic myocardial segments based on increase in myocardial blood flow (MBF) with vasodilatation.

Background

Myocardial ASL is a promising technique for the assessment of MBF because of the absence of contrast agents. Patients with end-stage renal disease cannot tolerate contrast agent, and therefore stand to potential benefit from myocardial ASL. MBF in healthy myocardium is known to increase by 4 times during vasodilator-induced stress, compared to at rest [1].

Methods

Twenty nine patients were recruited from those scheduled for routine cardiac MR (CMR) exams. All MRI experiments were performed on a GE Signa 3T scanner. Myocardial ASL measurements were obtained from a single mid short-axis slice, using flow-sensitive alternating inversion recovery (FAIR) tagging and balanced steady-state free precession (SSFP) imaging [2]. Rest-stress myocardial ASL scans were incorporated in CMR exam including first-pass imaging during adenosine infusion of 0.14 mg/kg/min (Figure 1). Based on CMR results, patients who were suspected to have severe ischemic heart disease also underwent X-ray angiography.
https://static-content.springer.com/image/art%3A10.1186%2F1532-429X-13-S1-O94/MediaObjects/12968_2011_Article_1563_Fig1_HTML.jpg
Figure 1

Imaging protocol excerpt.

Results

Among 29 patients, fifteen patients were found to be normal based on having no visible perfusion defect on first-pass MRI and no significant stenosis on X-ray angiogram. Ten patients had both perfusion defects and stenosis. Four remaining patients showed perfusion defects but no stenosis. Table 1 summarizes the perfusion analysis performed in both whole myocardium and myocardial segments after excluding subjects with signal-to-physiological-noise ratio<2.0 [2]. The normal segments included all six segments [3] of the whole myocardium in normal patients and ischemic segments included the most ischemic segments in the patients with stenosis confirmed by X-ray angiography. MBF increase with adenosine in the global and segmental myocardium in normal patients were both statistically significant with p<0.0001 while MBF increase with adenosine in ischemic segments were not statistically significant with p=0.1032, based on paired t-test. Difference in perfusion reserve (MBFstress/MBFrest) between normal and ischemic segments was statistically significant with p=0.0296, based on unpaired t-test.
Table 1

MBF at rest and during stress (ml/g/min) and perfusion reserve.

Subject

Normal whole myocardium

Normal myocardial segments

Ischemic myocardial segments

N

12

66

11

Condition

Rest

Stress

Rest

Stress

Rest

Stress

MBF

1.19±0.46

3.99±1.39

1.20±0.88

3.90±1.30

1.48±0.46

2.17±1.53

Reserve

4.21±3.44

2.87±2.10

1.44±0.97

Conclusion

This study has demonstrated that myocardial ASL is able to capture adenosine-induced MBF increase in normal myocardium while detecting insignificant increase in ischemic myocardium. This suggests that myocardial ASL with vasodilation has a potential to diagnose angiographically significant heart disease.

Authors’ Affiliations

(1)
University of Southern California
(2)
Loma Linda University Medical Center
(3)
University of California

References

  1. Kaufmann , et al: Am J Physiol Heart Circ Physiol. 2007Google Scholar
  2. Zun , et al: MRM. 2009Google Scholar
  3. Cerqueira , et al: Circulation. 2002Google Scholar

Copyright

© Zun et al; licensee BioMed Central Ltd. 2011

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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