Abstract 19661: Integrin Imaging for the Detection of Diffuse Myocardial Fibrosis in Patients with Hypertrophic Cardiomyopathy: Direct Comparison Between Single-Photon Emission Computer Tomography and Cardiovascular Magnetic Resonance The SCAR Study
Background Hypertrophic cardiomyopathy (HCM) promotes diffuse myocardial collagen synthesis, disarray and hypertrophy. Cardiovascular magnetic resonance (CMR) imaging using late gadolinium enhancement (LGE) can detect focal fibrosis in HCM, although the injury process in HCM may be global and diffuse. αvβ3 is a vitronectin integrin receptor associated with fibroblasts and collagen synthesis. A 99Technetium compound (99mTc-NC100692) that binds with high affinity to αvβ3 has been developed. Thus, we hypothesize that 99mTc-NC100692 could be used to detect focal and diffuse myocardial fibrosis in patients with HCM.
Methods 5 patients (62±11 years, 4 male) with a diagnosis of HCM from echocardiography were prospectively recruited. Patients underwent SPECT 99mTc-NC100692 and CMR LGE imaging. Using a 17-segment model, 99mTc-NC100692 images were visually assessed for myocardial uptake using a 3-point scale. LGE images were assessed for the presence or absence of enhancement per segment.
Results For the 5 patients, 85 segments were evaluated and all had some degree of 99mTc-NC100692 uptake. Three patients had evidence for focal LGE in 9 segments. Of these 9 segments, 5 had matched high-grade 99mTc-NC100692 uptake. One patient had strong apical 99mTc-NC100692 uptake without any evidence of hypertrophy nor LGE. The remaining 79 segments had low-grade 99mTc-NC100692 uptake with lack of evidence for LGE.
Conclusion Diffuse low-grade myocardial uptake of 99mTc-NC100692 in patients with HCM may be suggestive of diffuse fibrosis. 99mTc-NC10069 may serve as a marker of myocellular disarray although further studies are required to determine the specificity of 99mTc-NC100692.
- © 2012 by American Heart Association, Inc.