Author + information
- Received August 27, 2018
- Revision received May 7, 2019
- Accepted May 10, 2019
- Published online August 14, 2019.
- Shiro Nakamori, MDa,
- Ahmed Fahmy, PhDa,
- Jihye Jang, MSca,
- Hossam El-Rewaidy, MSca,
- Ulf Neisius, MDa,
- Sophie Berg, RNa,
- Beth Goddu, RTa,
- Patrick Pierce, RTa,
- Jennifer Rodriguez, BAa,
- Thomas Hauser, MDa,
- Long H. Ngo, PhDa,
- Warren J. Manning, MDa,b and
- Reza Nezafat, PhDa,∗ ()
- aDepartment of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
- bDepartment of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
- ↵∗Address for correspondence:
Dr. Reza Nezafat, Department of Medicine, Cardiovascular Division, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, Massachusetts 02215.
Objectives This study assessed changes in myocardial native T1 and T2 values after supine exercise stress in healthy subjects and in patients with suspected ischemia as potential imaging markers of ischemia.
Background With emerging data on the long-term retention of gadolinium in the body and brain, there is a need for an alternative noncontrast cardiovascular magnetic resonance (CMR)−based myocardial ischemia assessment.
Methods Twenty-eight healthy adult subjects and 14 patients with coronary artery disease (CAD) referred for exercise stress and/or rest single-photon emission computed tomography/myocardial perfusion imaging (SPECT/MPI) for evaluation of chest pain were prospectively enrolled. Free-breathing myocardial native T1 and T2 mapping were performed before and after supine bicycle exercise stress using a CMR-compatible supine ergometer positioned on the MR table. Differences in T1 rest, T2 rest and T1 post-exercise, T2 post-exercise values were calculated as T1 and T2 reactivity, respectively.
Results The mean exercise intensity was 104 W, with exercise duration of 6 to 12 min. After exercise, native T1 was increased in healthy subjects (p < 0.001). T1 reactivity, but not T2 reactivity, correlated with the rate−pressure product as the index of myocardial blood flow during exercise (r = 0.62; p < 0.001). In patients with CAD, T1 reactivity was associated with the severity of myocardial perfusion abnormality on SPECT/MPI (normal: 4.9%; quartiles: 3.7% to 6.3%, mild defect: 1.2%, quartiles: 0.08% to 2.5%; moderate defect: 0.45%, quartiles: −0.35% to 1.4%; severe defect: 0.35%, quartiles: −0.44% to 0.8%) and had similar potential as SPECT/MPI to detect significant CAD (>50% diameter stenosis on coronary angiography). The area under the receiver-operating characteristic curve was 0.80 versus 0.72 (p = 0.40). The optimum cutoff value of T1 reactivity for predicting flow-limiting stenosis was 2.5%, with a sensitivity of 83% and a specificity of 92%, a negative predictive value of 96%, a positive predictive value of 71%, and an area under the curve of 0.86.
Conclusions Free-breathing stress/rest native T1 mapping, but not T2 mapping, can detect physiological changes in the myocardium during exercise. Our feasibility study in patients shows the potential of this technique as a method for detecting myocardial ischemia in patients with CAD without using a pharmacological stress agent.
Dr. Nakamori is supported by a scholarship from Mie University Foundation International. Dr. Nezafat is supported by grants from the National Institutes of Health (R01HL129185, R01HL127015, R01HL129157, and AHA 15EIA22710040). All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received August 27, 2018.
- Revision received May 7, 2019.
- Accepted May 10, 2019.
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