Abstract TP168: Angiography-Like Grading of Carotid Artery Stenosis with B-Flow Ultrasound: 3D-Ultrasound Supported Comparison with Computer Tomography Angiography Results in a High Accuracy
Background: Evaluation of various imaging modalities for grading internal carotid artery (ICA) stenosis can be performed by comparison of minimal lumen diameters (MLD) as well as percent ICA-stenosis calculated with a healthy distal reference segment (NASCET method). The two dimensional B-Flow (BF) ultrasound (US) imaging method displays stenoses in a similar fashion as reference methods like multi-slice CT-angiography (MS CTA) and in part like catheter angiography.
Aim: to evaluate the accuracy of BF-US carotid stenosis grading at NASCET locations adjusted with 3D-color-Doppler ultrasound by comparison with MSCTA.
Methods: Patients were screened by doppler US velocity criteria after informed consent. 3D-US was made for distance taking and search for anatomical markers. CTA were compared with BF-US in 91 ICA stenoses of 69 patients at identical projections of longitudinal sections. 58 low to high grade ICA stenoses were imaged by selective angiography and compared with CTA. Diameters of stenosed ICA were rendered coaxial on CTA. Angiography was made with AXIOM (Siemens, Germany), MSCTA with SOMATOM (Siemens, Germany); Ultrasound Logic 9 with 8 Mhz linear scanner for BF-US and a 10 Mhz 3D-US probe, GE, USA. All readings were by two independent observers for each technique. Quantitative angiography was done with MEDIS software (Netherlands), Bland-Altman analysis and statistics with SPSS (USA). Identical planes were finally confirmed by overlay technique of BF with 3D-US and CTA in addtition to the use of anatomical markers.
Results: Degree of stenosis was slightly understimated by CTA compared with angiography with mean differences (±SD) of -0.4% (±6.1%) for longitudinal sections. In this cohort, discrimination of binary 50% NASCET stenosis with BF-US had a 90% sensitivity, 94% specifity and an accuracy of 91%; discrimination of binary 70% NASCET stenosis with BF-US had a sensitivity of 88%, specifity of 93% and an accuracy of 92%.
Conclusion: diagnostic performance of CTA proved to be excellent compared with angiography and 3D-US adjusted BF-US measurements were highly accurate, when using corresponding projections. BF-US may be a valuable additional tool for screening and confirmation of CAS for therapeutic stratification.
- © 2012 by American Heart Association, Inc.