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Updated: Aug 9, 2026
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Automated quantification of the spatial extent of perfusion defects and viability on myocardial contrast
Antonio Micari1, Jiri Sklenar, Todd A Belcik
1Cardiovascular Division, University of Virginia, Charlottesville, USA.
Insights
Pixel intensity threshold analysis (PITA) automates myocardial contrast echocardiography (MCE) to assess perfusion defect size. This method accurately quantifies infarct size, aiding in coronary artery disease patient treatment and clinical trials.
Area of Science:
- Cardiology
- Medical Imaging
- Computational Pathology
Background:
- Assessing myocardial perfusion and viability is crucial for managing coronary artery disease.
- Current methods for quantifying perfusion defects can be time-consuming and subjective.
- Automated analysis offers potential for more efficient and objective assessment.
Purpose of the Study:
- To evaluate the efficacy of computerized pixel intensity threshold analysis (PITA) for automated assessment of perfusion defect size in myocardial contrast echocardiography (MCE).
- To validate PITA's accuracy in determining infarct size compared to established methods.
Main Methods:
- MCE was performed in dogs for calibration, with infarct size determined by PITA using a 10% threshold.
- Clinical validation involved MCE in 30 acute myocardial infarction patients before and after percutaneous coronary intervention (PCI).
- PITA's defect size measurements were compared with expert reader planimetry on background-subtracted images.
Main Results:
- A 10% threshold in PITA demonstrated strong correlation with histologic staining for infarct size in canine models.
- In patients, PITA-derived defect size strongly correlated with expert planimetry (r = 0.95, P < .001).
- The PITA method proved effective in measuring both risk area and infarct size sequentially post-PCI.
Conclusions:
- Automated analysis of perfusion defect size using PITA on MCE is feasible and accurate.
- PITA offers a rapid, objective tool for analyzing ischemia and viability extent.
- This technique is valuable for clinical research requiring precise, sequential perfusion defect assessment.
Abstract:
The spatial extent of hypoperfusion or viability is important in the treatment of patients with coronary artery disease. We hypothesized that computerized pixel intensity threshold analysis (PITA) could be used for the automated analysis of perfusion defect size during myocardial contrast echocardiography (MCE). For calibration studies, MCE was performed in 6 dogs undergoing ischemia and reperfusion. Infarct size was determined by PITA, which automatically calculates the percentage of pixels within the myocardium that fail to exceed a predetermined threshold of maximum contrast enhancement. A threshold of 10% of maximum yielded infarct sizes that most closely correlated with those determined by histologic staining. For clinical validation, MCE was performed in 30 patients with acute myocardial infarction before primary percutaneous coronary intervention (PCI) for measurement of risk area; and within 5 days and at 4 weeks after PCI to determine infarct size. The defect size by PITA with a 10% threshold value closely correlated with those measured by expert reader planimetry on background-subtracted color-coded image sets (r = 0.95, P < .001). We conclude that automated analysis of perfusion defect size on MCE is possible by PITA. This technique may be useful for rapid and objective analysis of the extent of ischemia and viability, and for clinical experimentation where accurate and sequential analysis of perfusion defect size is imperative.
