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Direct Comparison of Virtual-Histology Intravascular Ultrasound and Optical Coherence Tomography Imaging for Identification of Thin-Cap Fibroatheroma.

Brown AJ, Obaid DR, Costopoulos C, Parker RA, Calvert PA, Teng Z, Hoole SP, West NE, Goddard M, Bennett MR - Circ Cardiovasc Imaging (2015)

Bottom Line: Combining VH-defined fibroatheroma and fibrous cap thickness ≤85 μm over 3 continuous frames improved TCFA identification, with diagnostic accuracy of 89.0%.Both VH-IVUS and OCT can reliably identify TCFA, although OCT accuracy may be improved using lipid arc ≥80° and fibrous cap thickness ≤85 μm over 3 continuous frames.Combined VH-IVUS/OCT imaging markedly improved TCFA identification.

View Article: PubMed Central - PubMed

Affiliation: From the Division of Cardiovascular Medicine (A.J.B., D.R.O., C.C., P.A.C., M.R.B.), Department of Radiology (Z.T.), and Department of Engineering (Z.T.), University of Cambridge, Cambridge, United Kingdom; Health Services Research Unit, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine. University of Edinburgh, Edinburgh, United Kingdom (R.A.P.); and Departments of Interventional Cardiology (S.P.H., N.E.J.W.) and Pathology (M.G.), Papworth Hospital NHS Trust, Cambridge, United Kingdom.

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Example of plaque incorrectly classified as optical coherence tomography thin-cap fibroatheroma (OCT-TCFA). A–D, Histological image of a fibroatheroma (A) displaying evidence of extracellular lipid accumulation (B) and thick (>65 μm) overlying fibrous cap (*) with coregistered OCT image (C). The OCT displays a signal-poor region with poorly delineated borders (D) correctly identifying lipid, but the minimal fibrous cap thickness (measured at arrow) was <85 μm, resulting in classification as OCT-TCFA.
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Figure 6: Example of plaque incorrectly classified as optical coherence tomography thin-cap fibroatheroma (OCT-TCFA). A–D, Histological image of a fibroatheroma (A) displaying evidence of extracellular lipid accumulation (B) and thick (>65 μm) overlying fibrous cap (*) with coregistered OCT image (C). The OCT displays a signal-poor region with poorly delineated borders (D) correctly identifying lipid, but the minimal fibrous cap thickness (measured at arrow) was <85 μm, resulting in classification as OCT-TCFA.

Mentions: Although individual features may differ subtly between TCFA and other fibroatheroma on VH-IVUS and OCT, plaque classification uses a combination of imaging features to define plaque type as compared with standard histological definitions (Figures 1 and 2; Methods section of Data Supplement). Overall, the prevalence of VH-TCFA was 20.9% and for OCT-TCFA was 20.2%. The diagnostic accuracies for any fibroatheroma and TCFA were 77.5% and 76.5% for VH-IVUS and 89.0% and 79.0% for OCT, respectively (Figure 4; Table 4), with sensitivities to detect TCFA of 63.6% (VH-IVUS) and 72.7% (OCT). The incorrectly classified TCFA showed several common features. For example, 7 of 8 TCFA (87.5%) not identified by VH-IVUS were classified as thick-cap fibroatheroma, indicating that although VH-IVUS can identify large areas of NC, it has difficulty discriminating thin fibrous caps. In contrast, false-positive VH-TCFA identification was commonly encountered in regions of calcification, where the adjacent plaque composition was incorrectly portrayed as NC (Figure 5). Three of six TCFA incorrectly classified by OCT had an LAmax <90° and 3 of 6 had FCTmin ≥85 μm (Figure 6), suggesting that current thresholds for TCFA identification by OCT may not be accurate.


Direct Comparison of Virtual-Histology Intravascular Ultrasound and Optical Coherence Tomography Imaging for Identification of Thin-Cap Fibroatheroma.

Brown AJ, Obaid DR, Costopoulos C, Parker RA, Calvert PA, Teng Z, Hoole SP, West NE, Goddard M, Bennett MR - Circ Cardiovasc Imaging (2015)

Example of plaque incorrectly classified as optical coherence tomography thin-cap fibroatheroma (OCT-TCFA). A–D, Histological image of a fibroatheroma (A) displaying evidence of extracellular lipid accumulation (B) and thick (>65 μm) overlying fibrous cap (*) with coregistered OCT image (C). The OCT displays a signal-poor region with poorly delineated borders (D) correctly identifying lipid, but the minimal fibrous cap thickness (measured at arrow) was <85 μm, resulting in classification as OCT-TCFA.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4596008&req=5

Figure 6: Example of plaque incorrectly classified as optical coherence tomography thin-cap fibroatheroma (OCT-TCFA). A–D, Histological image of a fibroatheroma (A) displaying evidence of extracellular lipid accumulation (B) and thick (>65 μm) overlying fibrous cap (*) with coregistered OCT image (C). The OCT displays a signal-poor region with poorly delineated borders (D) correctly identifying lipid, but the minimal fibrous cap thickness (measured at arrow) was <85 μm, resulting in classification as OCT-TCFA.
Mentions: Although individual features may differ subtly between TCFA and other fibroatheroma on VH-IVUS and OCT, plaque classification uses a combination of imaging features to define plaque type as compared with standard histological definitions (Figures 1 and 2; Methods section of Data Supplement). Overall, the prevalence of VH-TCFA was 20.9% and for OCT-TCFA was 20.2%. The diagnostic accuracies for any fibroatheroma and TCFA were 77.5% and 76.5% for VH-IVUS and 89.0% and 79.0% for OCT, respectively (Figure 4; Table 4), with sensitivities to detect TCFA of 63.6% (VH-IVUS) and 72.7% (OCT). The incorrectly classified TCFA showed several common features. For example, 7 of 8 TCFA (87.5%) not identified by VH-IVUS were classified as thick-cap fibroatheroma, indicating that although VH-IVUS can identify large areas of NC, it has difficulty discriminating thin fibrous caps. In contrast, false-positive VH-TCFA identification was commonly encountered in regions of calcification, where the adjacent plaque composition was incorrectly portrayed as NC (Figure 5). Three of six TCFA incorrectly classified by OCT had an LAmax <90° and 3 of 6 had FCTmin ≥85 μm (Figure 6), suggesting that current thresholds for TCFA identification by OCT may not be accurate.

Bottom Line: Combining VH-defined fibroatheroma and fibrous cap thickness ≤85 μm over 3 continuous frames improved TCFA identification, with diagnostic accuracy of 89.0%.Both VH-IVUS and OCT can reliably identify TCFA, although OCT accuracy may be improved using lipid arc ≥80° and fibrous cap thickness ≤85 μm over 3 continuous frames.Combined VH-IVUS/OCT imaging markedly improved TCFA identification.

View Article: PubMed Central - PubMed

Affiliation: From the Division of Cardiovascular Medicine (A.J.B., D.R.O., C.C., P.A.C., M.R.B.), Department of Radiology (Z.T.), and Department of Engineering (Z.T.), University of Cambridge, Cambridge, United Kingdom; Health Services Research Unit, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine. University of Edinburgh, Edinburgh, United Kingdom (R.A.P.); and Departments of Interventional Cardiology (S.P.H., N.E.J.W.) and Pathology (M.G.), Papworth Hospital NHS Trust, Cambridge, United Kingdom.

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Related in: MedlinePlus