Elsevier

Journal of Nuclear Cardiology

Volume 29, Issue 6, December 2022, Pages 3267-3277
Journal of Nuclear Cardiology

Original Article
Three-dimensional Fusion of Myocardial Perfusion SPECT and Invasive Coronary Angiography Guides Coronary Revascularization

https://doi.org/10.1007/s12350-022-02907-8Get rights and content

Abstract

Background

SPECT myocardial perfusion imaging (SPECT MPI) and invasive coronary angiography (ICA) provide complementary clinical information in the diagnosis of coronary artery disease (CAD). We have developed an approach for 3D fusion of perfusion data from SPECT MPI and coronary anatomy from ICA. In this study, we aimed to evaluate its clinical value when compared to the traditional side-by-side readings.

Methods

Thirty-six CAD patients who had at least one stenosis ≥ 50% were retrospectively enrolled. Based on the presence of a perfusion defect in a territory subtended by a coronary vessel, all vessels were classified as matched, unmatched, or normal groups via both the fusion and side-by-side analysis. The treatments recommended by the fusion and side-by-side analysis were compared with those that the patients received. Major adverse cardiac events (MACE), defined as all-cause death, myocardial infarction, unstable angina requiring hospitalization, and unplanned revascularization, were assessed.

Results

The overall vessel-based concordance was 78.7% between the fusion and side-by-side analysis. Compared with the side-by-side analysis, 23 coronary arteries (29 equivocal segments) of 19 patients were reclassified via fusion of data. In the matched, unmatched, and normal groups, the numbers of vessels with hemodynamically significant stenosis which caused reversible defect were 37 vs 53, 28 vs 14, and 43 vs 41 (P < .01) when comparing the side-by-side analysis with the fusion, and the revascularization ratios per vessel were 69% vs 88%, 29% vs 10%, and 2% vs 2% between them. During the five-year follow-up, 8 patients (22.2%) experienced MACE. Patients who received the same treatment as the guidance of 3D fusion results (n = 22) had superior outcomes when compared with those who did not (n = 14) (P < .01).

Conclusions

Compared with the side-by-side analysis, the 3D fusion of SPECT MPI and ICA provided incremental diagnostic and prognostic value.

Introduction

The degree of coronary stenosis on invasive coronary angiography (ICA) is considered as the gold standard for the diagnosis and treatment of coronary artery disease (CAD). However, anatomical stenosis does not always contribute to inducible ischemia on perfusion imaging. Hemodynamically significant coronary artery stenosis refers to coronary artery lesion, from atherosclerosis, or spasm resulting in hypoperfusion of a given myocardial territory.1 The ideal tool to evaluate coronary circulation should provide both anatomical and physiological information.

Myocardial perfusion imaging (MPI) using single-photon emission computed tomography (SPECT) is a well-established non-invasive method that has been widely used to assess the functional significance of coronary stenosis. SPECT MPI has been recommended as a gatekeeper prior to ICA, to inform revascularization2 and such an approach is associated with an excellent prognosis. However, as a non-invasive test, values of SPECT MPI are limited by low sensitivity, issues with image quality, and the possibility of balanced ischemia. Moreover, the misassignment of myocardial segments to the concerned coronary arteries obtained by coronary computed tomography angiography (CCTA) is quite common. It has been reported that 72% of patients have arterial distribution different from the standard assignment in at least one myocardial segment due to patient-specific variations of the coronary anatomy.3

The combination of anatomy and physiology by fusion of imaging data may have a role in improving the diagnosis and management of CAD.4 Current guidelines recommend that patients with low-to-intermediate pretest probability for stable CAD undergo CCTA, which has a high negative predictive value, while patients with intermediate-to-high pretest probability should be referred for functional testing, including SPECT MPI. Nevertheless, most of the existing studies focused on the fusion between SPECT MPI and CCTA, but few studies have reported results on the utility of fusion of SPECT MPI and ICA data. We have previously developed a 3D fusion approach that combines SPECT MPI and ICA with a high technical accuracy to guide myocardial revascularization.5,6 In this study, we aim to evaluate the diagnostic and prognostic values of the 3D fusion approach compared to the side-by-side analysis.

Section snippets

Study Population

We retrospectively analyzed SPECT MPI and ICA data from 36 patients, all of whom had suspected CAD. For each patient, SPECT MPI was acquired before ICA and the time interval between them was 10.5 ± 14.5 days (all < 3 months). All patients included in this analysis had at least one segment stenosis (≥ 50%) diagnosed by ICA. The exclusion criteria were (1) previous bypass graft lesion or stent implantation, (2) previous myocardial infarction, (3) dilated cardiomyopathy (DCM), (4) hypertrophic

Patient Characteristics

Thirty-six patients who meet the inclusion criteria were analyzed. Baseline characteristics of the study population are listed in Table 1.

SPECT MPI Results

SPECT revealed abnormal perfusion in 27 patients, including 9 fixed, 20 reversible, and 1 mixed perfusion defect. Among the perfusion defects, 18 defects were in the anterior and septal wall, 11 were in the inferior wall, and 11 were in the posterior and lateral wall. Nine patients did not have any perfusion abnormality on MPI.

ICA Results

A total of 697 coronary segments

Discussion

Our study demonstrates that compared with the side-by-side analysis, the SPECT/ICA fusion could (1) significantly reduce the number of coronary stenosis segments with uncertainty, especially for the LCX artery, (2) guide the decision making for patient treatment which could improve the prognosis of CAD.

Revascularization based only on the anatomical criteria has been proved to have no additional benefit for long-term survival, and guidelines recommend the proof of ischemia prior to

Study Limitations

The study is limited by its observational nature. Due to the small number of patients studied, independent predictors of MACE could not be assessed. A larger prospective study will be needed to confirm the independent prognostic value of our fusion methodology. Additionally, abnormalities on MPI were not categorized as ischemia or infarction or both. While categorizing these defects may have a value in predicting outcomes after revascularization, this is not the focus of this pilot study and

New Knowledge Gained

The fusion between perfusion data from SPECT MPI and coronary anatomy from invasive coronary angiography reduced the number of equivocal coronary segments. Patients who received the same treatment as the guidance of 3D fusion results had superior outcomes when compared with those who did not.

Conclusions

Compared with the side-by-side analysis, 3D fusion between SPECT MPI and ICA provided incremental diagnostic and prognostic values for revascularization.

Acknowledgments

The authors have indicated they have no financial conflict of interest.

Disclosures

None of the authors, including Zhihui Xu, Haipeng Tang, Saurabh Malhotra, Minghao Dong, Chen Zhao, Zekang Ye, Ying Zhou, Shun Xu, Dianfu Li, Cheng Wang and Weihua Zhou, has any relevant conflicts of interest.

Funding

This research was supported by a new faculty grant from Michigan Technological University Institute of Computing and Cybersystems (PI: Weihua Zhou), a seed grant from Michigan Technological University Health Research

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    The authors of this article have provided a PowerPoint file, available for download at SpringerLink, which summarises the contents of the paper and is free for re-use at meetings and presentations. Search for the article DOI on SpringerLink.com.

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    Zhihui Xu and Haipeng Tang contributed equally to this work.

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