Skip to content

Advertisement

  • Oral presentation
  • Open Access

Blood oxygen level-dependent magnetic resonance imaging at 3 Tesla in coronary artery disease: validation using quantitative coronary angiography and cardiovascular magnetic resonance perfusion imaging

  • 1,
  • 1,
  • 2,
  • 1,
  • 1,
  • 1,
  • 1,
  • 2,
  • 1,
  • 1,
  • 3 and
  • 4
Journal of Cardiovascular Magnetic Resonance201012 (Suppl 1) :O34

https://doi.org/10.1186/1532-429X-12-S1-O34

  • Published:

Keywords

  • Cardiovascular Magnetic Resonance
  • Quantitative Coronary Angiography
  • Cardiovascular Magnetic Resonance Perfusion
  • Hyperemic Myocardial Blood Flow
  • Signal Intensity Threshold

Background

By exploiting the paramagnetic properties of deoxyhemoglobin, blood oxygen level-dependent (BOLD) MRI can be used to determine myocardial oxygenation. In this study involving human subjects, we used BOLD and perfusion MRI at 3 Tesla to investigate the relationship between coronary artery stenosis, myocardial perfusion and tissue oxygenation. We sought (1) to define a threshold for BOLD MRI to identify myocardium subtended by coronary stenosis, and (2) to determine its diagnostic accuracy in patients with suspected CAD.

Methods

Subjects were studied at 3 Tesla (Trio, Siemens Medical Solutions). Ischemic thresholds for BOLD and first-pass perfusion imaging were determined in 25 patients (age 61 ± 7) with known CAD and 20 normal volunteers (age 53 ± 7). These thresholds were then applied in a consecutive series of 60 patients with suspected CAD, in whom diagnostic angiography was scheduled to investigate exertional chest pain.

For BOLD MRI, mid-ventricular short-axis images were acquired at rest and stress (4-5 minutes intravenous adenosine, 140 μg/kg/min) using a T2-prepared SSFP sequence (echo time 1.43 ms, repetition time 2.86 ms, T2 preparation time 40 ms, matrix 168 × 192, slice thickness 8 mm, flip angle 44°). First-pass perfusion imaging was then performed in the same slice locations following intravenous Gadolinium-DTPA bolus injections (0.04 mmol/kg, Gadodiamide, Omniscan™, GE Healthcare) using a T1-weighted fast gradient echo sequence (echo time 1.04 ms, repetition time 2 ms, voxel size 2.1 × 2.6 × 8 mm3). Absolute quantification of perfusion was performed using model-independent deconvolution. For BOLD analysis, stress signal intensity (SI) was indexed to resting SI using a segmental approach. Quantitative coronary angiography was used to evaluate segmental coronary stenosis: a reduction in luminal diameter of > 50% was deemed significant.

Results

In the validation arm, taking QCA as the gold standard, cut-off values to define ischemic segments were derived for hyperemic myocardial blood flow (<2.1 ml/min/g - AUC 0.72) and BOLD SI change (<5.2% - AUC 0.64). In the prospective arm, the complete imaging protocol was performed in 57 individuals (age 61 ± 9, CAD prevalence 68%). On a per subject basis, applying the BOLD SI threshold provided diagnostic accuracy 83%, sensitivity 94% and specificity 56% for the detection of CAD (compared with 84%, 95% and 61%, respectively for perfusion imaging). On a per subject basis, agreement between BOLD and perfusion imaging was 81%.

Conclusion

BOLD imaging at 3 Tesla is comparable with first-pass perfusion imaging, and yields favorable diagnostic accuracy in the detection of significant CAD.

Authors’ Affiliations

(1)
John Radcliff Hospital, Oxford, UK
(2)
Hammersmith Hospital, London, UK
(3)
Brigham Women's Hospital, Boston, MA, USA
(4)
Flinders Medical Centre, Adelaide, Australia

Copyright

© Arnold et al; licensee BioMed Central Ltd. 2010

This article is published under license to BioMed Central Ltd.

Advertisement