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This article is part of the supplement: Proceedings of the Eighth Annual MCBIOS Conference. Computational Biology and Bioinformatics for a New Decade

Open Access Proceedings

Validation of an arterial tortuosity measure with application to hypertension collection of clinical hypertensive patients

Karl T Diedrich12*, John A Roberts1, Richard H Schmidt3, Chang-Ki Kang4, Zang-Hee Cho4 and Dennis L Parker12

Author Affiliations

1 Utah Center for Advanced Imaging Research, Department of Radiology, University of Utah, 729 Arapeen Drive, Salt Lake City, UT 84108, USA

2 Department of Biomedical Informatics, University of Utah, 26 South 2000 East Room 5775 HSEB, Salt Lake City, UT 84112, USA

3 Department of Neurosurgery, University of Utah, Health Science Center, Bldg 550, 5th Floor, 175 N. Medical Drive East, Salt Lake City, UT 84132, USA

4 Neuroscience Research Institute, Gachon University of Medicine and Science 1198, Kuwol-dong, Namdong-gu, Incheon, 405-760, Korea

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BMC Bioinformatics 2011, 12(Suppl 10):S15  doi:10.1186/1471-2105-12-S10-S15

Published: 18 October 2011

Abstract

Background

Hypertension may increase tortuosity or twistedness of arteries. We applied a centerline extraction algorithm and tortuosity metric to magnetic resonance angiography (MRA) brain images to quantitatively measure the tortuosity of arterial vessel centerlines. The most commonly used arterial tortuosity measure is the distance factor metric (DFM). This study tested a DFM based measurement’s ability to detect increases in arterial tortuosity of hypertensives using existing images. Existing images presented challenges such as different resolutions which may affect the tortuosity measurement, different depths of the area imaged, and different artifacts of imaging that require filtering.

Methods

The stability and accuracy of alternative centerline algorithms was validated in numerically generated models and test brain MRA data. Existing images were gathered from previous studies and clinical medical systems by manually reading electronic medical records to identify hypertensives and negatives. Images of different resolutions were interpolated to similar resolutions. Arterial tortuosity in MRA images was measured from a DFM curve and tested on numerically generated models as well as MRA images from two hypertensive and three negative control populations. Comparisons were made between different resolutions, different filters, hypertensives versus negatives, and different negative controls.

Results

In tests using numerical models of a simple helix, the measured tortuosity increased as expected with more tightly coiled helices. Interpolation reduced resolution-dependent differences in measured tortuosity. The Korean hypertensive population had significantly higher arterial tortuosity than its corresponding negative control population across multiple arteries. In addition one negative control population of different ethnicity had significantly less arterial tortuosity than the other two.

Conclusions

Tortuosity can be compared between images of different resolutions by interpolating from lower to higher resolutions. Use of a universal negative control was not possible in this study. The method described here detected elevated arterial tortuosity in a hypertensive population compared to the negative control population and can be used to study this relation in other populations.