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MRI detection of myocardial perfusion defects due to coronary artery stenosis with MS-325
Dara L Kraitchman1, Bennett B Chin, Alan W Heldman
1Departments of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-0845, USA. dara@mri.jhu.edu
Purpose:
To assess the value of an intravascular, albumin-targeted contrast agent, MS-325, in visualizing myocardial ischemia with magnetic resonance imaging (MRI).
Materials And Methods:
Left anterior descending coronary artery (LAD) stenosis was created in 19 pigs using a closed-chest modified angioplasty technique. Myocardial ischemia was detected by first-pass, contrast-enhanced MRI at peak dipyridamole stress and was compared to Technetium-99m (Tc-99m) sestamibi single photon emission computed tomography (SPECT). Regional coronary blood flow was determined using microspheres.
Results:
Inducible myocardial ischemia with >40% reduction in stress myocardial blood flow was created in eight animals. An MRI defect, classified as > or=75% reduction in peak myocardial signal intensity in the affected territory, was detected in 92.3% of these animals. In the presence of mild coronary stenosis, there was uniform enhancement with MRI and tracer uptake by SPECT. Concordance of MRI and SPECT for detecting perfusion defects was 85%.
Conclusion:
The pattern of prolonged and persistent MR hypoenhancement of the ischemic myocardial bed using MS-325, which is retained primarily in the vascular bed due to its albumin-binding properties, facilitates the detection of myocardial perfusion defects.
Insights
MS-325, an albumin-targeted contrast agent, effectively visualizes myocardial ischemia using magnetic resonance imaging (MRI). This agent aids in detecting perfusion defects by showing prolonged hypoenhancement in ischemic areas.
Area of Science:
- Cardiovascular Imaging
- Magnetic Resonance Imaging
- Myocardial Perfusion Assessment
Background:
- Myocardial ischemia detection is crucial for diagnosing and managing coronary artery disease.
- Traditional imaging techniques have limitations in sensitivity and specificity.
- Novel contrast agents are needed to improve diagnostic accuracy.
Purpose of the Study:
- To evaluate the diagnostic performance of MS-325, an intravascular, albumin-targeted contrast agent, for visualizing myocardial ischemia using MRI.
- To compare the efficacy of MS-325 enhanced MRI with established methods like SPECT for myocardial perfusion assessment.
Main Methods:
- Created left anterior descending coronary artery (LAD) stenosis in pigs to induce myocardial ischemia.
- Utilized first-pass, contrast-enhanced MRI during dipyridamole stress to detect ischemia.
- Compared MRI findings with Technetium-99m (Tc-99m) sestamibi single-photon emission computed tomography (SPECT) and measured regional coronary blood flow using microspheres.
Main Results:
- Successfully induced myocardial ischemia in 8 out of 19 animals, characterized by >40% reduction in stress myocardial blood flow.
- MRI detected perfusion defects with 92.3% sensitivity (defined as > or =75% reduction in peak myocardial signal intensity).
- Achieved 85% concordance between MRI and SPECT in identifying perfusion defects, with uniform enhancement observed in mild stenosis cases.
Conclusions:
- MS-325 demonstrates significant value in visualizing myocardial ischemia via MRI.
- The agent's albumin-binding property leads to prolonged, persistent hypoenhancement in ischemic myocardial beds, facilitating defect detection.
- MS-325 enhanced MRI shows promise as a reliable tool for assessing myocardial perfusion defects.