Stähr Peter M, Höfflinghaus Tobias, Voigtländer Thomas, Courtney Brian K, Victor Anja, Otto Mike, Yock Paul G, Brennecke Rüdiger, Fitzgerald Peter J
Stanford University Medical School, Stanford, California 94305, USA.
Am J Cardiol. 2002 Jul 1;90(1):19-23. doi: 10.1016/s0002-9149(02)02379-2.
Radiofrequency intravascular ultrasound (IVUS-RF) analysis, as an extension of conventional IVUS imaging, may provide more accurate plaque discrimination. Thirty-two autopsy atherosclerotic coronary arteries were investigated. Corresponding sectors in different plaques were matched by histologic and RF analysis. Histologic analysis utilized the American Heart Association plaque classification. The backscattered ultrasound RF signal was analyzed by fast-Fourier transform, providing the underlying frequency components of its power spectrum. The normalized backscattered signal power (in decibels [dB]) for frequencies between 15.3 and 40.3 MHz was then measured for plaque discrimination. Advanced/complicated plaque types showed a higher signal power at all frequencies than early/intermediate lesion types (p <0.001 to p = 0.005). Discrimination of advanced/complicated lesion types was best at 15.3 MHz, with a cut-off point of 2.5 dB (sensitivity 93%, specificity 79%), and second best at 17.6 MHz (sensitivity 87%, specificity 71%, cut-off point 1.9 dB). With conventional IVUS, plaque discrimination was weaker; the best sensitivity for diagnosing early/intermediate lesion types was reached for "soft plaque" (sensitivity 63%, specificity 73%). Compared with conventional IVUS, IVUS-RF can discriminate between advanced/complicated and early/intermediate coronary atherosclerotic lesions with relatively high sensitivity and specificity in vitro.
作为传统血管内超声成像的扩展，射频血管内超声（IVUS-RF）分析可能提供更准确的斑块鉴别。对32例尸检的动脉粥样硬化冠状动脉进行了研究。通过组织学和射频分析匹配不同斑块中的相应区域。组织学分析采用美国心脏协会的斑块分类。通过快速傅里叶变换分析反向散射超声射频信号，提供其功率谱的潜在频率成分。然后测量15.3至40.3MHz频率范围内的归一化反向散射信号功率（以分贝[dB]为单位）用于斑块鉴别。晚期/复杂斑块类型在所有频率下的信号功率均高于早期/中期病变类型（p<0.001至p = 0.005）。在15.3MHz时对晚期/复杂病变类型的鉴别最佳，截止点为2.5dB（敏感性93%，特异性79%），在17.6MHz时次之（敏感性87%，特异性71%，截止点1.9dB）。对于传统血管内超声，斑块鉴别能力较弱；对于“软斑块”，诊断早期/中期病变类型的最佳敏感性为63%，特异性为73%。与传统血管内超声相比，IVUS-RF在体外能够以相对较高的敏感性和特异性区分晚期/复杂和早期/中期冠状动脉粥样硬化病变。
