Accuracy of In Vivo Coronary Plaque Morphology Assessment
A Validation Study of In Vivo Virtual Histology Compared With In Vitro Histopathology
Kenya Nasu, MD*,*,
Etsuo Tsuchikane, MD, PhD*,
Osamu Katoh, MD*,
D. Geoffrey Vince, PhD ,
Renu Virmani, MD ,
Jean-François Surmely, MD*,
Akira Murata, MD*,
Yoshihiro Takeda, MD*,
Tatsuya Ito, MD*,
Mariko Ehara, MD*,
Tetsuo Matsubara, MD*,
Mitsuyasu Terashima, MD* and
Takahiko Suzuki, MD, PhD*
* Department of Cardiology, Toyohashi Heart Center, Toyohashi-city, Aichi, Japan
Department of Biomedical Engineering, The Cleveland Clinic Foundation, Cleveland, Ohio
Department of Cardiovascular Pathology, Armed Forces Institute of Pathology, Washington, DC.
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Figure 1 Schematic description of the procedure and data acquisition. After the initial angiogram, intravascular ultrasound (IVUS) with electrocardiogram-gated radiofrequency (RF) data was recorded. Directional coronary atherectomy was performed just one time with high pressure at the target lesion, and the tissue sample was extracted from the atherocatheter for post-processing. After debulking, an angiogram and electrocardiogram-gated RF data acquisition were performed.
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Figure 2 Schematic description of the Virtual Histology (VH) intravascular ultrasound procedure and in vitro histopathology correlation analysis for a heart rate of about 60 beats/min. After the proximal end of debulking was detected, the longitudinal distance from the proximal end to the most proximal VH image (distance 0) was calculated. Knowing the R-R interval (s) and the pullback speed of the intravascular ultrasound catheter (0.5 mm/s), the distance between each VH images was calculated as follows: distance between two VH images (mm) = R-R interval x 0.5. The distance between sections was calculated as 0.5 mm (= each distance of cutting tissue) times the ratio of pre-fixed length of tissue sample (mm) to post-fixed length (mm). The VH image that was closest to each section was chosen as the corresponding color-coded map, and the debulked area on pre-debulking VH images was predicted by comparison of pre- with post-debulking VH images. The predicted debulking area was compared visually with the histology section to assess the presence or absence of the four different components.
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Figure 3 Pre-debulking gray scale intravascular ultrasound images, color-coded maps of pre- and post-debulking target lesions reconstructed by Virtual Histology intravascular ultrasound, and histology sections. (Case 1) Acute coronary syndrome. (1a) Gray scale intravascular ultrasound image at the target lesion. Note the heterogeneity of the plaque beside the plate of calcium with acoustic shadow. (1b) Pre-debulking color-coded map of 1a reconstructed by virtual histology intravascular ultrasound. Note the superficial necrotic core (red) beside the plate of the dense calcium (white). (1c) Post-debulking color-coded map. Predicted debulking area within the blue circle in 1b. (1d) Histologic finding with fibrous tissue, fibro-fatty plaque, and necrotic core. (Case 2) Stable angina pectoris. (2a) Gray scale intravascular ultrasound image of target lesion. Note the heterogeneity of the plaque. (2b) Pre-debulking color-coded map of 2a reconstructed by virtual histology intravascular ultrasound. Note the necrotic core (red) with thick fibrous cap consisting of fibrous tissue (green) and fibro-fatty plaque (yellow). (2c) Post-debulking color-coded map. Predicted debulking area within the blue circle in 2b. (2d) Histologic finding with fibrous tissue and fibro-fatty plaque. Bars = 500 µm.
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