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  • Open Access

Assessment of semi-quantitative parameters for visual interpretation of stress-perfusion CMR in obstructive coronary artery disease

  • 1,
  • 1,
  • 1,
  • 1,
  • 2, 1,
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  • 1
Journal of Cardiovascular Magnetic Resonance201315 (Suppl 1) :P210

https://doi.org/10.1186/1532-429X-15-S1-P210

  • Published:

Keywords

  • Invasive Coronary Angiography
  • Obstructive Coronary Artery Disease
  • Adenosine Stress
  • Transmural Extent
  • Rest Perfusion

Background

Adenosine stress CMR with visual interpretation is increasingly used in the evaluation of patients with CAD. The definition of a stress perfusion defect is inconsistent in the literature regarding i) the duration from contrast arrival, ii) persistence relative to a remote segment, iii) transmural extent, and iv) reversibility on rest perfusion.

In this study we sought to test several semi-quantitative parameters assessed by rapid visual analysis, and determine their utility to identify stress-perfusion defects from obstructive CAD.

Methods

25 patients (61±14 years, 44% male) with known CAD and ≥70% stenosis on invasive coronary angiography (CA) were studied (60% single-vessel, 40% two-vessel disease). All patients underwent CMR within 2 months of CA, typically, four short-axis images were obtained each heartbeat during adenosine stress and rest. Patients with infarction, revascularization, and cardiomyopathy were excluded.

Stress and rest perfusion images were analyzed visually using a 16-segment model. The number of frames from left-ventricular (LV) cavity peak contrast to myocardial signal homogeneity (MET) within each segment was assessed (n=400 segments). We scored the transmural extent (in quartiles) of any segmental hypoenhancement persiting ≥1 frame beyond the first homogenous segment in the same slice. CA was reviewed to determine for each segment, whether they are subtended by a stenotic coronary artery ("ischemic" vs "non-ischemic" segments).

Results

The input function (number of frames from LV contrast arrival to LV peak contrast enhancement) ranged between 4-7 frames (median 5, IQR 4-6) in all patients. There were 154 ischemic and 246 non-ischemic segments. Nine non-ischemic segments had a matched rest perfusion defect (e.g. artifactual), none of the ischemic segments showed a rest perfusion defect. MET for ischemic segments was longer (median 22, interquartile range [IQR] 14-30) than in non-ischemic segments (7, IQR 5-8, p<0001), however, 38% of segments overlapped (Figure 1a). Most non-ischemic segments were concurrently homogenous (0, IQR 0-0), in two segments hypoenhancement persisted for >3 frames, both had matched rest perfusion defects (Figure 1b). In ischemic segments hypoenhancement persisted for a median of 14 (IQR 8-22) frames (p<0.0001), with a minimum of 4 frames. The transmural extent of hypoenhancement (Figure 1c) was higher in ischemic segments (3, IQR 2-3) compared to non-ischemic segments (0, IQR 0-0], 139 (90.3%) ischemic segments were >25% transmural.
Figure 1
Figure 1

Results of different semi-quantitative parameters (Myocardial Enhancement Time, Persistence of Hypoenhancement, Transmural Extent of Hypoenhancement) derived from the visual interpretation of Stress-Perfusion CMR. The frequency of non-ischemic and ischemic segments in each group is expressed as percent of the total number of non-ischemic or ischemic segments, respectively. A) Frequency of non-ischemic (blue) segments and ischemic (red) segments according to groups of different Myocardial Enhancement Times (x-axis) in frames. B) Frequency of non-ischemic (blue) segments and ischemic (red) segments according to the Persistence of Hypoenhancement (x-axis) in frames. C) Frequency of non-ischemic (blue) segments and ischemic (red) segments according to the Transmural Extent of Hypoenhancement (x-axis) in quartiles.

Conclusions

Stress-perfusion defects in obstructive CAD tend to be >25% in transmural extent, persist for >4 frames, and have no corresponding rest perfusion defects.

Funding

none

Authors’ Affiliations

(1)
Duke Cardiovascular Magnetic Resonance Center, Duke University, Durham, NC, USA
(2)
Siemens Healthcare, Chapel Hill, NC, USA

Copyright

© Jensen et al; licensee BioMed Central Ltd. 2013

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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