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Detection of acute myocardial ischemia using first-pass dynamics of MnDPDP on inversion recovery echoplanar imaging
R Wyttenbach1, M Saeed, M F Wendland
1Department of Radiology, University of California at San Francisco 94143-0628, USA.
Abstract:
Previous studies used manganese N,N'-bis-(pyridoxal 5-phosphate)ethylenediamine-N,N'-diacetic acid (MnDPDP) to detect myocardial ischemia at a dose of 0.4 mmol/kg with spin echo imaging. The purpose of this study was to detect acute myocardial ischemia using MnDPDP at a dose range near that approved for hepatobiliary imaging (0.005 mmol/kg) in conjunction with inversion recovery echoplanar imaging (IR EPI). Regional ischemia was produced in 26 rats by occluding the left coronary artery for 20-30 minutes before imaging. Consecutive 32 IR EP images (inversion time [TI]/TR/TE 700/2000/10 msec) were obtained to monitor the first pass of MnDPDP at four incremental doses (0.005, 0.01, 0.02, or 0.04 mmol/kg, n = 6-8). MnDPDP produced dose-dependent enhancement of left ventricular blood and normal myocardium, but not ischemic myocardium. Quantitative analysis revealed a difference in signal intensities (P<0.05) between normal and ischemic myocardium at the time of peak enhancement in all groups. However, differential enhancement between normal and ischemic myocardium produced clear visual delineation of the ischemic region only at doses > or =0.01 mmol/kg. In conclusion, acute myocardial ischemia can be detected with IR EPI using doses close to the clinically approved dose of MnDPDP.
Insights
Manganese N,N'-bis-(pyridoxal 5-phosphate)ethylenediamine-N,N'-diacetic acid (MnDPDP) effectively detects acute myocardial ischemia using low doses with inversion recovery echoplanar imaging (IR EPI). This method offers clear visual delineation of ischemic regions near clinically approved MnDPDP dosages.
Area of Science:
- Cardiovascular Imaging
- Medical Diagnostics
- Pharmacology
Background:
- Previous studies utilized manganese N,N'-bis-(pyridoxal 5-phosphate)ethylenediamine-N,N'-diacetic acid (MnDPDP) at high doses (0.4 mmol/kg) for myocardial ischemia detection.
- Spin echo imaging was the modality used in prior research.
Purpose of the Study:
- To evaluate the efficacy of MnDPDP for detecting acute myocardial ischemia at doses near those approved for hepatobiliary imaging (0.005 mmol/kg).
- To assess the utility of inversion recovery echoplanar imaging (IR EPI) in conjunction with MnDPDP for this purpose.
Main Methods:
- Acute regional myocardial ischemia was induced in 26 rats by left coronary artery occlusion.
- Consecutive IR EPI images were acquired during the first pass of MnDPDP at incremental doses (0.005 to 0.04 mmol/kg).
Main Results:
- MnDPDP demonstrated dose-dependent enhancement in left ventricular blood and normal myocardium, but not in ischemic areas.
- A statistically significant difference (P<0.05) in signal intensity was observed between normal and ischemic myocardium.
- Clear visual delineation of ischemic regions was achieved at MnDPDP doses of 0.01 mmol/kg and above.
Conclusions:
- Acute myocardial ischemia can be detected using IR EPI with MnDPDP at doses approaching the clinically approved level for hepatobiliary imaging.
- This approach offers a potential method for diagnosing myocardial ischemia with lower contrast agent doses.