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Visualisation of arterial structure in vivo with intravascular ultrasound
R Jeremy1, E Hasche, E Sinclair
1University of Sydney, Department of Cardiology, Royal Prince Alfred Hospital, NSW.
Insights
Intravascular ultrasound (IVUS) offers detailed arterial wall imaging, surpassing contrast angiography. IVUS accurately measures vascular geometry and detects early atherosclerosis not visible with traditional methods.
Area of Science:
- Cardiovascular imaging
- Medical device technology
- Vascular pathology
Background:
- Contrast angiography visualizes arterial lumen but not wall structure.
- Catheter-tip ultrasound transducers provide cross-sectional arterial wall imaging.
- This study correlates intravascular ultrasound (IVUS) images with arterial pathology and assesses measurement accuracy.
Purpose of the Study:
- To evaluate the pathological correlation of IVUS images.
- To determine the accuracy of IVUS measurements of vascular geometry.
- To compare IVUS with contrast angiography for detecting arterial lesions.
Main Methods:
- IVUS imaging using a mechanically rotated catheter-tip transducer.
- Validation in post-mortem arterial specimens with saline filling.
- Comparison of IVUS images and measurements with pathological findings and angiography.
- In vivo studies in human aorta, ilio-femoral, and coronary arteries.
Main Results:
- IVUS detects early arterial thickening and mild atherosclerotic lesions without luminal deformation.
- Ultrasound images define calcified, fibrotic, and lipid-filled lesions.
- IVUS measurements of luminal diameter (r=0.93) and plaque area (r=0.89) correlate well with pathology.
- IVUS identifies atheroma lesions missed by angiography and evaluates interventions like balloon angioplasty.
Conclusions:
- IVUS provides unique insights into human arterial structure and pathology.
- IVUS enables accurate vascular geometry measurements.
- IVUS defines early atheromatous lesions undetectable by angiography.
Background:
Contrast angiography provides a silhouette of the arterial lumen, but does not give information about arterial wall structure. Catheter-tip ultrasound transducers can now provide a cross-sectional image of the arterial wall. This study examined the pathological correlation of intravascular ultrasound images and the accuracy of ultrasound measurements of vascular geometry.
Methods:
Intravascular ultrasound images were obtained with a mechanically rotated catheter-tip transducer and recorded on videotape. Initial validation studies were performed in fresh, post-mortem arterial specimens, which were filled with saline at physiological pressures. Ultrasound images at specific sites were compared with the pathological findings at that site and measurements of luminal diameter were compared with corresponding angiographic measurements. Subsequently, intravascular ultrasound was employed to examine the aorta, ilio-femoral and coronary arteries in patients undergoing balloon angioplasty.
Results:
The pathological correlations showed that intravascular ultrasound can detect early initial thickening and mild atherosclerotic lesions that do not result in luminal deformation. Ultrasound images provided definition of calcified, fibrotic and lipid-filled lesions. Ultrasound measurements of luminal diameter correlated well with pathology measurements (r = 0.93), as did ultrasound measurements of plaque area (r = 0.89). The in vivo studies demonstrated that intravascular ultrasound can define atheroma lesions not evident on contrast angiography and permits detailed evaluation of the results of interventions such as balloon angioplasty.
Conclusions:
Intravascular ultrasound provides a unique window upon arterial structure and pathology in humans. Ultrasound images allow accurate measurements of vascular geometry and define early atheromatous lesions that are not evident with angiography.