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Volumetric intracoronary ultrasound

Dhawale, Paritosh Jayant
http://rave.ohiolink.edu/etdc/view?acc_num=case1057677172

Abstract Details

1994, Doctor of Philosophy, Case Western Reserve University, Biomedical Engineering.
Three dimensional analysis using intracoronary ultrasound (ICUS) pull-back data provides the unique ability to quantitate lumen and atherosclerotic plaque volumes. Unlike x-ray angiography which measures only the lumen, ICUS provides direct information about plaque volume distribution. ICUS volumetric analysis is required in order to understand mechanisms of coronary interventions, restenosis, and regression. In this study we developed and validated volumetric ICUS methodology. In the first part of the study, optimal data acquisition parameters for volumetric acquisition were established using simulations on computer phantoms of stenotic arteries. Eleven computer phantoms were generated using cross-sectional area data from quantitative angiography of stenotic coronary arteries. Three methods of data acquisition were simulated: conventional manual pull-back; motorized pull-back; and manual pull-back with measured displacement. Effects of pull-back velocity and cardiac gating on cross-sectional area profiles and volumes were studied. We rated the methods, measured ~ motorized >> manual. Cardiac gating eliminated errors introduced by vessel deformation within a cardiac cycle. With cardiac gating, pull-backs with mean velocities up to 1.2 mm/sec allowed reconstruction of cross-sectional area profiles within 5% RMS error. With faster pull-backs, cardiac gating resulted in sparse spatial samp ling and significant errors in cross-sectional area profiles. The accuracy of both motorized and measured required equal displacements of the catheter proximal and distal ends. This assumption was validated with in-vitro experiments where x-ray fluoroscopy was used to measure the displacement of the imaging tip. Excellent correlation was found between the two displacements (r = 0.99). Finally, slow pull-backs were performed by 3 operators, and pull-back velocities were measured. It was found that mean pull-back velocities as low as 0.8 mm/sec were achievable. In the second part of the study, we developed a real-time, ICUS pull-back data acquisition scheme to acquire calibrated, cardiac-gated 3D image data sets. A semi-automated border detection scheme was implemented using dynamic programming. To validate the ICUS methodology, multiple pull-backs were performed in phantoms. ICUS volumes were very reproducible (~3% standard deviation) and were close to independently obtained volume measurements obtained from water weight (mean error ~5%). The ICUS volumes also correlated with angiographic analysis which is the current gold standard in coronary imaging (mean error ~1.6%). Clinical applicability was assessed by performing 10 cardiac gated pull-backs in 5 patients before and after directional coronary atherectomy (DCA). Lumen and plaque volumes over the length of the DCA cutter showed that lumen volume improvement occurred due to plaque removal (45%) and vessel expansion (55%). Angiographic measurements of lumen volumes compared favorably. We conclude that volumetric ICUS provides accurate and reproducible estimates and, unlike angiography, provides a direct in-vivo technique for quantifying atherosclerotic plaque volumes. The technique will have direct clinical applicability in regression and restenosis trails.
n/a n/a (Advisor)
169 p.
Engineering, Biomedical
Volumetric intracoronary ultrasound.

Recommended Citations

Citations

  • Dhawale, P. J. (1994). Volumetric intracoronary ultrasound [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1057677172

    APA Style (7th edition)

  • Dhawale, Paritosh. Volumetric intracoronary ultrasound. 1994. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1057677172.

    MLA Style (8th edition)

  • Dhawale, Paritosh. "Volumetric intracoronary ultrasound." Doctoral dissertation, Case Western Reserve University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=case1057677172

    Chicago Manual of Style (17th edition)

case1057677172
501
© 1994, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.