Real-time cine first-pass perfusion imaging enables rapid detection of functionally significant high-grade coronary stenosis

  • Behzad Sharif
  • Reza Arsanjani
  • Hsin-Jung Yang
  • Rohan Dharmakumar
  • Noel Bairey C Merz
  • Daniel S Berman
  • Debiao Li
Open Access
Oral presentation

Keywords

Left Anterior Descend Perfusion Defect Right Coronary Artery Coronary Stenosis Transient Ischemic Dilation 

Background

Among the spectrum of patients with coronary artery disease (CAD), those suffering from high-grade stenosis are at a significantly elevated risk for adverse events [1]. Such high-grade disease may result in the so-called "coronary steal" phenomenon under vasodilator stress [2] thereby inducing wall-motion abnormalities (WMAs) in the affected territories, referred to as transient ischemic dilation. We developed a "real time" cine first-pass perfusion (FPP) CMR method for concurrent imaging of myocardial function and perfusion. We hypothesized that this method is capable of simultaneously capturing stress-induced perfusion defects and WMAs in a single ungated scan.

Methods

Canines (n=9) with surgically implemented reversible stenosis below the first diagonal along the left anterior descending (LAD) artery (≈90% stenosis) were studied at 3T. Real-time adenosine stress/rest cine perfusion data was acquired using an ungated continuously-sampled FPP sequence without saturation recovery preparation [3, 4]. The T1-weighted acquisition scheme used a steady-state FLASH sequence with 3-5 slice coverage and no time-gap in between consecutive slice-interleaved radial readouts, acquiring 5,000 projections per slice during the 40-second real-time FPP scan (flip: 30°, echo spacing: 2.7 ms, in-plane resolution: 1.4x1.4 mm2). Retrospective cardiac self-gating was performed automatically using a high temporal-resolution reconstruction of the mid slice at low spatial resolution. The self-gating information was then used to perform a cardiac phase-resolved reconstruction of the FPP data for all slices at high resolution employing a compressed sensing approach. WM for the cine perfusion images was scored on a standard 1-4 scale. To test the clinical feasibility of this approach, patients (n=3) with known high-grade (≥90%) right coronary artery (RCA) stenosis were studied.

Results

Real-time stress FPP scans in stenotic dogs (Fig. 1) showed worsening of WM in the perfusion defect territories compared to resting function, consistent with ischemic dilation (slice-averaged stress WM score for defect region: 2.8 vs. 1.6 for rest; p < 0.05). The close agreement of WMA vs. standard cine (Fig. 1) indicates the high temporal resolution of the real-time method. The mid-slice inferior perfusion defect in the example patient study (Fig. 2) coincides with the WMA (larger LV cavity area) compared to rest function, consistent with the angiogram. The other 2 patients showed similar results.
Figure 1

Representative images from the ischemic canine stress/rest studies (n=9) with high-grade LAD stenosis. (a,b): End-systolic adenosine stress and rest first-pass perfusion images (peak enhancement phase) using the developed real-time cine FPP technique. All of the stress-induced perfusion defect territories (arrows) show WMAs compared to the rest scan (larger end-systolic LV cavity area at stress compared to rest), consistent with the coronary steal (ischemic dilation) phenomenon. (c): standard SSFP cine end-systolic images (mid slice), showing a similar stress-versus-rest WMA pattern as in (a,b). This confirms that the real-time cine perfusion technique was capable of accurately capturing the wall motion at stress (i.e., achieving sufficiently high temporal resolution).

Figure 2

Representative CAD patient study with high-grade RCA stenosis. (a): End-systolic frames (peak myocardial enhancement phase) corresponding to the proposed real-time cine first-pass perfusion method at the apical, mid, and basal ventricular levels. (b): standard SSFP cine scan (end-systolic frames) in the same 3 slices performed at baseline (resting state) prior to adenosine infusion. (c): invasive coronary angiogram. The observed stress perfusion defects (yellow arrows) are consistent with the angiogram in (c), which shows a high-grade stenosis (≈90%) in proximal RCA (dominant vessel) and ≈70% stenosis in mid LAD. For the mid slice, the perfusion defect territory (inferior wall) shows WMA in comparison to the baseline end-systolic frame, i.e., a larger end-systolic LV cavity area is seen in (a2) compared to (b2). This is consistent with the angiographically documented high-grade RCA stenosis.

Conclusions

We presented a multi-slice cine FPP method capable of simultaneous detection of stress-induced perfusion defects and WMAs in a single ungated scan using continuous acquisition (<1 minute). Our initial results demonstrate that worsening of WM (compared to rest) in the perfusion defect territories seen in the real-time stress cine FPP scan may be a marker of severe CAD.

Funding

American Heart Association Scientist Development Grant 14SDG20480123; NIH National Heart, Lung and Blood Institute grant nos. K99 HL124323-01, R01 HL038698-18, R01 HL091989-05, R01 HL090957-01.

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Copyright information

© Sharif et al; licensee BioMed Central Ltd. 2015

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/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Authors and Affiliations

  • Behzad Sharif
    • 1
  • Reza Arsanjani
    • 1
    • 2
  • Hsin-Jung Yang
    • 1
  • Rohan Dharmakumar
    • 1
    • 2
  • Noel Bairey C Merz
    • 2
  • Daniel S Berman
    • 1
    • 2
  • Debiao Li
    • 1
    • 2
  1. 1.Biomedical Imaging Research InstituteCedars-Sinai Medical CenterLos AngelesUSA
  2. 2.Cedars-Sinai Heart InstituteLos AngelesUSA

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