Original Research
Integrating CT Myocardial Perfusion and CT-FFR in the Work-Up of Coronary Artery Disease

https://doi.org/10.1016/j.jcmg.2016.09.028Get rights and content
Under an Elsevier user license
open archive

Abstract

Objectives

The aim of this study was to investigate the individual and combined accuracy of dynamic computed tomography (CT) myocardial perfusion imaging (MPI) and computed tomography angiography (CTA) fractional flow reserve (FFR) for the identification of functionally relevant coronary artery disease (CAD).

Background

Coronary CTA has become an established diagnostic test for ruling out CAD, but it does not allow interpretation of the hemodynamic severity of stenotic lesions. Two recently introduced functional CT techniques are dynamic MPI and CTA FFR using computational fluid dynamics.

Methods

From 2 institutions, 74 patients (n = 62 men, mean age 61 years) planned for invasive angiography with invasive FFR measurement in 142 vessels underwent CTA imaging and dynamic CT MPI during adenosine vasodilation. A patient-specific myocardial blood flow index was calculated, normalized to remote myocardial global left ventricular blood flow. CTA FFR was computed using an on-site, clinician-operated application. Using binary regression, a single functional CT variable was created combining both CT MPI and CTA FFR. Finally, stepwise diagnostic work-up of CTA FFR with selective use of CT MPI was simulated. The diagnostic performance of CT MPI, CTA FFR, and CT MPI integrated with CTA FFR was evaluated using C statistics with invasive FFR, with a threshold of 0.80 as a reference.

Results

Sensitivity, specificity, and accuracy were 73% (95% confidence interval [CI]: 61% to 86%), 68% (95% CI: 56% to 80%), and 70% (95% CI: 62% to 79%) for CT MPI and 82% (95% CI: 72% to 92%), 60% (95% CI: 48% to 72%), and 70% (63% to 80%) for CTA FFR. For CT MPI integrated with CTA FFR, diagnostic accuracy was 79% (95% CI: 71% to 87%), with improvement of the area under the curve from 0.78 to 0.85 (p < 0.05). Accuracy of the stepwise approach was 77%.

Conclusions

CT MPI and CTA FFR both identify functionally significant CAD, with comparable accuracy. Diagnostic performance can be improved by combining the techniques. A stepwise approach, reserving CT MPI for intermediate CTA FFR results, also improves diagnostic performance while omitting nearly one-half of the population from CT MPI examinations.

Key Words

coronary artery disease
CT angiography
CTA FFR
CT myocardial perfusion

Abbreviations and Acronyms

AIF
arterial input function
AUC
area under the curve
CAD
coronary artery disease
CT
computed tomography
CTA
computed tomography angiography
FFR
fractional flow reserve
IQR
interquartile range
MBF
myocardial blood flow
MBF(LV)75%
myocardial blood flow of the myocardial segment representing the 75th percentile
MPI
myocardial perfusion imaging

Cited by (0)

Drs. Coenen, Lubbers, and Nieman were supported by a grant from the Dutch Heart Foundation (NHS 2014T061). This work forms part of the translational research portfolio of the National Institute for Health Research Cardiovascular Biomedical Research Unit at Barts, which is supported and funded by the National Institute for Health Research (Dr. Pugliese). Dr. Rossi is a recipient of a Training Grant from the European Society of Cardiology (2014). Dr. Dijkshoorn is a consultant for Siemens AG. Dr. van Geuns has received speaking fees from Abbott Vascular. Dr. Nieman has received institutional research support from Bayer Healthcare, GE Healthcare, Siemens Medical Solutions, and HeartFlow. Dr. Pugliese has received research support from Siemens Healthcare; and speaking fees from Bracco Diagnostics. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. Drs. Pugliese and Nieman contributed equally to this work.