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Intramyocardial vascular volume distribution studied by synchrotron radiation-excited X-ray fluorescence
Y Nakajima1, N Akizuki, Y Kimura
1Department of Physiology, Tokai University School of Medicine, Bohseidai, Isehara, Kanagawa 259-1193, Japan.
Insights
This study reveals significant variability in myocardial vascular volume distribution within the left ventricle. These findings highlight the complex, asymmetric nature of the intramural coronary vascular network.
Area of Science:
- Cardiovascular Physiology
- Myocardial Anatomy
- Vascular Biology
Background:
- Understanding myocardial vascular volume distribution is crucial for assessing cardiac function and disease.
- Previous studies have provided limited resolution on intramyocardial vascular architecture.
Purpose of the Study:
- To precisely evaluate vascular volume distribution in the left ventricle's sagittal plane.
- To characterize the variability, self-similarity, and spatial correlation of myocardial vascular volume.
Main Methods:
- Utilized the microsphere filling method for fine-resolution analysis (0.1-1.3 mg myocardial tissue).
- Analyzed coronary arterial volume density in the sagittal plane of the left ventricle in 21 dogs.
- Employed fractal analysis to assess vascular volume distribution and correlation patterns.
Main Results:
- Coronary arterial volume density showed non-normal distribution with significant variability across and within myocardial layers.
- Median vascular volume density ranged from 4.7 to 22.9 nl/mg myocardial tissue.
- Fractal analysis indicated self-similarity (fractal dimension ~1.2) and greater variability than flow distribution, with asymmetric correlations between adjacent regions.
Conclusions:
- Intramyocardial vascular volume density in the sagittal plane is highly variable, self-similar, and exhibits asymmetric regional correlations.
- These characteristics are likely inherent to the intramural coronary vascular network's structure.
- Findings provide novel insights into myocardial vascular architecture and its functional implications.
Abstract:
We evaluated the vascular volume distribution with fine resolution (0.1-1.3 mg myocardial tissue) in the sagittal plane of the left ventricle by using the microsphere filling method in 21 dogs. The coronary arterial volume density in the sagittal plane did not exhibit normal distribution and was characterized by variability among the outer-to-inner layers and within the layers (+2SD/-2SD > 80 times), and the median values in the layers ranged from 4.7 to 22. 9 nl/mg myocardial tissue. The fractal analysis of vascular volume revealed a self-similar nature with a fractal dimension (D value) similar to that of flow distribution (1.20 +/- 0.05 and 1.24 +/- 0. 09 for vascular volume and flow distribution, respectively) and had a more marked variability than the flow. The correlation of the regional vascular volume between adjacent regions decreased as the distance increased. However, the correlation coefficients in the endocardial-to-epicardial direction were significantly higher than those in the anterior-to-posterior direction (P < 0.05 by paired t-test). In conclusion, we determined intramyocardial vascular volume density in the sagittal plane, and the distribution revealed considerable variability, self-similarity, and asymmetry in the correlation among the adjacent regions. These observations could be related to the characteristics of the intramural coronary vascular network.