Heart 1998;79:459-467 ( May )

Characterisation of coronary atherosclerotic morphology by spectral analysis of radiofrequency signal: in vitro intravascular ultrasound study with histological and radiological validation

M P Moore,^a T Spencer,^b D M Salter,^a P P Kearney,^a T R D Shaw,^a I R Starkey,^a P J Fitzgerald,^c R Erbel,^d A Lange,^a N W McDicken,^b G R Sutherland,^a K A A Fox^a

^a Department of Cardiology, University of Edinburgh, Edinburgh, UK, ^b Department of Medical Physics, University of Edinburgh, ^c Cardiovascular Research Institute, University of California, San Francisco, California, USA, ^d Department of Cardiology, University of Essen, Essen, Germany

Correspondence to: Dr M P Moore, 41 Crystal Terrace,, Burlingame, CA 94010, USA.

Accepted for publication 14 November 1997

ObjectiveTo determine whether spectral analysis of unprocessed radiofrequency (RF) signal offers advantages over standard videodensitometric analysis in identifying the morphology of coronary atherosclerotic plaques.
Methods97 regions of interest (ROI) were imaged at 30 MHz from postmortem, pressure perfused (80 mm Hg) coronary arteries in saline baths. RF data were digitised at 250 MHz. Two different sizes of ROI were identified from scan converted images, and relative amplitudes of different frequency components were analysed from raw data. Normalised spectra was used to calculate spectral slope (dB/MHz), y-axis intercept (dB), mean power (dB), and maximum power (dB) over a given bandwidth (17-42 MHz). RF images were constructed and compared with comparative histology derived from microscopy and radiological techniques in three dimensions.
ResultsMean power was similar from dense fibrotic tissue and heavy calcium, but spectral slope was steeper in heavy calcium (0.45 (0.1)) than in dense fibrotic tissue (0.31 (0.1)), and maximum power was higher for heavy calcium (7.7 (2.0)) than for dense fibrotic tissue (10.2 (3.9)). Maximum power was significantly higher in heavy calcium (7.7 (2.0) dB) and dense fibrotic tissue (10.2 (3.9) dB) than in microcalcification (13.9  (3.8) dB). Y-axis intercept was higher in microcalcification (5.8 (1.1) dB) than in moderately fibrotic tissue (11.9  (2.0) dB). Moderate and dense fibrotic tissue were discriminated with mean power: moderate 20.2 (1.1) dB, dense 14.7 (3.7) dB; and y-axis intercept: moderate 11.9 (2.0) dB, dense 5.5  (5.4) dB. Different densities of fibrosis, loose, moderate, and dense, were discriminated with both y-axis intercept, spectral slope, and mean power. Lipid could be differentiated from other types of plaque tissue on the basis of spectral slope, lipid 0.17 (0.08). Also y-axis intercept from lipid (17.6 (3.9)) differed significantly from moderately fibrotic tissue, dense fibrotic tissue, microcalcification, and heavy calcium. No significant differences in any of the measured parameters were seen between the results obtained from small and large ROIs.
ConclusionFrequency based spectral analysis of unprocessed ultrasound signal may lead to accurate identification of atherosclerotic plaque morphology.

Keywords: tissue characterisation;  intravascular ultrasound;  spectral analysis;  radiofrequency data

---

© 1998 by Heart
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• BRODOEFEL, H, BURGSTAHLER, C, HEUSCHMID, M, REIMANN, A, KHOSA, F, KOPP, A, SCHROEDER, S, CLAUSSEN, C D, CLOUSE, M E (2009). Accuracy of dual-source CT in the characterisation of non-calcified plaque: use of a colour-coded analysis compared with virtual histology intravascular ultrasound. Br. J. Radiol. 82: 805-812 [Abstract] [Full Text]  
• Wang, H.-W., Langohr, I. M., Sturek, M., Cheng, J.-X. (2009). Imaging and Quantitative Analysis of Atherosclerotic Lesions by CARS-Based Multimodal Nonlinear Optical Microscopy. Arterioscler. Thromb. Vasc. Bio. 29: 1342-1348 [Abstract] [Full Text]  
• Marso, S. P., Mehta, S. K., Frutkin, A., House, J. A., McCrary, J. R., Kulkarni, K. R. (2008). Low Adiponectin Levels Are Associated With Atherogenic Dyslipidemia and Lipid-Rich Plaque in Nondiabetic Coronary Arteries. Diabetes Care 31: 989-994 [Abstract] [Full Text]  
• Voros, S. (2008). Can Computed Tomography Angiography of the Coronary Arteries Characterize Atherosclerotic Plaque Composition?: Is the CAT (Scan) Out of the Bag?. J Am Coll Cardiol Intv 1: 183-185 [Full Text]  
• Kawaguchi, R., Oshima, S., Jingu, M., Tsurugaya, H., Toyama, T., Hoshizaki, H., Taniguchi, K. (2007). Usefulness of Virtual Histology Intravascular Ultrasound to Predict Distal Embolization for ST-Segment Elevation Myocardial Infarction. J Am Coll Cardiol 50: 1641-1646 [Abstract] [Full Text]  
• Konig, A., Klauss, V. (2007). Virtual histology. Heart 93: 977-982 [Abstract] [Full Text]  
• Mehta, S. K., McCrary, J. R., Frutkin, A. D., Dolla, W. J.S., Marso, S. P. (2007). Intravascular ultrasound radiofrequency analysis of coronary atherosclerosis: an emerging technology for the assessment of vulnerable plaque. Eur Heart J 28: 1283-1288 [Abstract] [Full Text]  
• Granada, J. F., Wallace-Bradley, D., Win, H. K., Alviar, C. L., Builes, A., Lev, E. I., Barrios, R., Schulz, D. G., Raizner, A. E., Kaluza, G. L. (2007). In Vivo Plaque Characterization Using Intravascular Ultrasound-Virtual Histology in a Porcine Model of Complex Coronary Lesions. Arterioscler. Thromb. Vasc. Bio. 27: 387-393 [Abstract] [Full Text]  
• Vengrenyuk, Y., Carlier, S., Xanthos, S., Cardoso, L., Ganatos, P., Virmani, R., Einav, S., Gilchrist, L., Weinbaum, S. (2006). A hypothesis for vulnerable plaque rupture due to stress-induced debonding around cellular microcalcifications in thin fibrous caps. Proc. Natl. Acad. Sci. USA 103: 14678-14683 [Abstract] [Full Text]  
• Nasu, K., Tsuchikane, E., Katoh, O., Vince, D. G., Virmani, R., Surmely, J.-F., Murata, A., Takeda, Y., Ito, T., Ehara, M., Matsubara, T., Terashima, M., Suzuki, T. (2006). Accuracy of In Vivo Coronary Plaque Morphology Assessment: A Validation Study of In Vivo Virtual Histology Compared With In Vitro Histopathology. J Am Coll Cardiol 47: 2405-2412 [Abstract] [Full Text]  
• Nair, A., Kuban, B. D., Tuzcu, E. M., Schoenhagen, P., Nissen, S. E., Vince, D. G. (2002). Coronary Plaque Classification With Intravascular Ultrasound Radiofrequency Data Analysis. Circulation 106: 2200-2206 [Abstract] [Full Text]  
• Yamagishi, M., Terashima, M., Awano, K., Kijima, M., Nakatani, S., Daikoku, S., Ito, K., Yasumura, Y., Miyatake, K. (2000). Morphology of vulnerable coronary plaque: insights from follow-up of patients examined by intravascular ultrasound before an acute coronary syndrome. J Am Coll Cardiol 35: 106-111 [Abstract] [Full Text]