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Primary Outcome Assessment in a Pig Model of Acute Myocardial Infarction
Published on: October 14, 2016
Early ischemia in growing piglet skeleton: MR diffusion and perfusion imaging
Nina M Menezes1, Susan A Connolly, Frederic Shapiro
1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, and Harvard Medical School, Boston 02129, USA. nmenezes@nmr.mgh.harvard.edu
Radiology
|December 23, 2006
Summary
Diffusion magnetic resonance imaging detects early ischemia in piglets, showing elevated apparent diffusion coefficients (ADCs) even after blood flow restoration. Histologic changes explain these diffusion changes in prolonged ischemia.
Area of Science:
- Biomedical imaging
- Radiology
- Orthopedics
Background:
- Ischemia can lead to significant structural and biochemical changes in tissues.
- Diffusion magnetic resonance (MR) imaging offers insights into tissue microstructure.
- Gadolinium-enhanced imaging assesses blood flow and vascularity.
Purpose of the Study:
- To evaluate diffusion changes in ischemic hips over time.
- To compare diffusion imaging with gadolinium-enhanced imaging in ischemia.
- To identify structural and biochemical factors influencing diffusion changes.
Main Methods:
- Surgically induced ischemia in piglet hips, with contralateral hips as controls.
- Line-scan diffusion and dynamic gadolinium-enhanced MR imaging at multiple time points.
- Calculation of apparent diffusion coefficients (ADCs) and enhancement ratios (ERs), followed by histologic evaluation.
Main Results:
- Ischemic hips showed no flow at 48 hours, with partial reperfusion by 1-4 weeks.
- Apparent diffusion coefficients (ADCs) were elevated early and remained high despite reperfusion.
- Histologic findings revealed cartilage thickening and altered marrow composition, explaining elevated ADCs.
Conclusions:
- Diffusion imaging is sensitive to early ischemia, preceding reperfusion.
- Diffusion changes have a different time course than gadolinium enhancement.
- Elevated ADCs in prolonged ischemia persist despite restored blood flow.
