Volume 34, Issue 2 p. 744-753
Ultrasound physics

Novel approach to evaluating breast density utilizing ultrasound tomography

Carri Glide

Carri Glide

Karmanos Cancer Institute, 110 East Warren, Hudson-Webber Cancer Research Center, Room 7040, Detroit, Michigan 48201

Author to whom correspondence should be addressed. Electronic mail: [email protected]

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Nebojsa Duric

Nebojsa Duric

Karmanos Cancer Institute, 110 East Warren, Hudson-Webber Cancer Research Center, Room 7040, Detroit, Michigan 48201

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Peter Littrup

Peter Littrup

Karmanos Cancer Institute, 110 East Warren, Hudson-Webber Cancer Research Center, Room 7040, Detroit, Michigan 48201

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First published: 30 January 2007
Citations: 59

Abstract

Women with high mammographic breast density have a four- to fivefold increased risk of developing breast cancer compared to women with fatty breasts. Many preventative strategies have attempted to correlate changes in breast density with response to interventions including drugs and diet. The purpose of this work is to investigate the feasibility of assessing breast density with acoustic velocity measurements with ultrasound tomography, and to compare the results with existing measures of mammographic breast density. An anthropomorphic breast tissue phantom was first imaged with our computed ultrasound tomography clinical prototype. Strong positive correlations were observed between sound speed and material density, and sound speed and computed tomography number (Pearson correlation urn:x-wiley:0094-2405:media:mp8408:mp8408-math-0001 and 0.91, respectively). A cohort of 48 women was then imaged. Whole breast acoustic velocity was determined by creating image stacks and evaluating the sound speed frequency distribution. The acoustic measures of breast density were evaluated by comparing these results to two mammographic density measures: (1) qualitative estimates determined by a certified radiologist using the BI-RADS Categorical Assessment based on a 1 (fatty) to 4 (dense) scale, and (2) quantitative measurements via digitization and computerized analysis of archival mammograms. A one-way analysis of variance showed that a significant difference existed between the mean values of sound speed according to BI-RADS category, while post hoc analyses using the Scheffé criterion for significance indicated that BI-RADS 4 (dense) patients had a significantly higher sound speed than BI-RADS 1, 2, and 3 at an alpha level of 0.05. Using quantitative measures of breast density, a direct correlation between the mean acoustic velocity and calculated mammographic percent breast density was demonstrated with correlation coefficients ranging from 0.75 to 0.89. The results presented here support the hypothesis that sound speed can be used as an indicator of breast tissue density. Noninvasive, nonionizing monitoring of dietary and chemoprevention interventions that affect breast density are now possible.