Radioiodinated hypericin as a tracer for detection of acute myocardial infarction: SPECT-CT imaging in a swine model.

Abstract

PURPOSE:

Hypericin (Hyp) is a natural compound with a newly discovered necrosis-avidity, which can be exploited as a necrosis-avid tracer once labeled with radioactive iodine as has been tested in rodent models. This study was to evaluate the effect of radioiodinated Hyp (131I-Hyp) for imaging detection of acute myocardial infarction (AMI) in conditions closer to clinical scenarios.

METHODS:

We established swine AMI models (n = 6) which were intravenously given 131I-Hyp and 99mTc-sestamibi and underwent SPECT-CT imaging with high- and low-energy collimators. The acquired SPECT images were fused with cardiac CT images and correlated with postmortem autoradiography and macro- and microscopic pathology. Tissue γ counting was performed to determine biodistribution of 131I-Hyp.

RESULTS:

131I-Hyp based SPECT indicated clearly hot regions on ventricular walls which were all histologically proved as AMI. Complementally, the hot AMI regions on 131I-Hyp SPECT (infarct/myoc ratio of 15.3 ± 7.7) were inversely cold regions on 99mTc-sestamibi SPECT (infarct/myoc ratio of 0.029 ± 0.021). Autoradiography of heart slices showed 9.8 times higher 131I-Hyp uptake in infarcted over normal myocardium. With γ counting, the mean 131I-Hyp uptake in infarcts was 10.69 ID%/g, 12.05 times of that in viable myocardium.

CONCLUSION:

131I-Hyp shows a potential for clinical detection of AMI once I-131 is substituted by its isotope like I-124 or I-123 for PET or SPECT, respectively.

• Authors: Shuping Yang, Junting Ma, Tian Li, Peng Wang, Xudan Wang, Jian Zhang, Yicheng Ni, Haibo Shao
• Journal: Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology (J Nucl Cardiol) Vol. 29 Issue 6 Pg. 3432-3439 (12 2022) ISSN: 1532-6551 [Electronic] United States
• PMID: 35296972 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.

Chemical References

• Iodine-131
• Iodine Radioisotopes
• hypericin
• Technetium Tc 99m Sestamibi

Topics

• Animals
• Swine
• Iodine Radioisotopes
• Tissue Distribution
• Thyroid Neoplasms
• Myocardial Infarction (diagnostic imaging, pathology)
• Necrosis
• Tomography, Emission-Computed, Single-Photon
• Tomography, X-Ray Computed
• Technetium Tc 99m Sestamibi