Intravascular Palpography for Vulnerable Plaque Assessment
Johannes A. Schaar, MD*, ,*,
Anton F.W. van der Steen, PhD*,,
Frits Mastik*,
Radj A. Baldewsing, MSc* and
Patrick W. Serruys, MD, PhD*
* Thoraxcenter, Erasmus Medical Center, Rotterdam
Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands
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Figure 1 Principle of the intravascular elastography measurement procedure. An intravascular ultrasound (IVUS) image is acquired with a low (P2) and a high (P1) intraluminal pressure. Using cross-correlation analysis on the high-frequency radiofrequency data, the radial strain in the tissue is determined. This information is superimposed on the IVUS image. In this example, an eccentric soft lesion is visible between the 6- and 12-o’clock positions in the elastogram where it cannot be identified from the IVUS image.
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Figure 2 Intravascular ultrasound (IVUS) image (A) and elastogram (B) with corresponding histology of a coronary artery with a vulnerable plaque. The IVUS image reveals an eccentric plaque between the 6- and 12-o’clock positions. The elastogram shows high-strain regions (yellow) at the shoulders of the plaque surrounded by low-strain values (blue). The histology reveals a plaque with a typical vulnerable appearance: A thin cap with a lack of collagen at the shoulders (C) and a large atheroma with heavy infiltration of macrophages (D).
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Figure 3 In vivo intravascular ultrasound image and palpogram of a human coronary artery. The elastogram reveals that the plaque has soft edges with adjacent hard (calcified) tissue. Plaque deformability was scored according to the Rotterdam classification (ROC), in which ROC I and IV indicate low (0% to 0.6%) and very high (>1.2%) deformation, respectively, by strain.
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