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Lowerison MR, Tse JJ, Hague MN, Chambers AF, Holdsworth DW, Lacefield JC. Compound speckle model detects anti-angiogenic tumor response in preclinical nonlinear contrast-enhanced ultrasonography. Med Phys 2017; 44:99-111. [PMID: 28102955 DOI: 10.1002/mp.12030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/30/2016] [Accepted: 11/22/2016] [Indexed: 01/01/2023] Open
Abstract
PURPOSE This paper proposes a method for analyzing the first-order speckle statistics of nonlinear contrast-enhanced ultrasound images from tumors. METHODS Contrast signal intensity is modeled as a compound distribution of exponential probability density functions with a gamma weighting function. The gamma probability weighting function serves as an approximation for log-normally distributed flow velocities in a vascular network. The model was applied to sub-harmonic bolus-injection images acquired from a mouse breast cancer xenograft model treated with murine version bevacizumab. RESULTS The area under curve produced using the compound statistical model could more accurately discriminate anti-VEGF-treated tumors from untreated tumors than conventional contrast-enhanced ultrasound image processing. This result was validated with gold standard histological measures of microvascular density. Fractal vessel geometry was estimated using the gamma weighting function and tested against micro-CT perfusion casting. Treated tumors had a significantly lower vascular fractal dimension than control tumors. Vascular complexity estimated using the ultrasound compound statistical model performed similarly to micro-CT fractal dimension for discriminating treated from control tumors. CONCLUSION The proposed technique can quantify tumor perfusion and provide an index of vascular complexity, making it a potentially useful addition for clinical detection of vascular normalization in anti-angiogenic trials.
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Affiliation(s)
- Matthew R Lowerison
- Department of Medical Biophysics, Western University, London, ON, N6A 3K7, Canada.,Robarts Research Institute, Western University, London, ON, N6A 5B7, Canada
| | - Justin J Tse
- Department of Medical Biophysics, Western University, London, ON, N6A 3K7, Canada.,Robarts Research Institute, Western University, London, ON, N6A 5B7, Canada
| | - M Nicole Hague
- London Regional Cancer Program, London Health Sciences Centre, London, ON, N6A 4L6, Canada
| | - Ann F Chambers
- London Regional Cancer Program, London Health Sciences Centre, London, ON, N6A 4L6, Canada.,Departments of Oncology and Medical Biophysics, Western University, London, ON, N6A 3K7, Canada
| | - David W Holdsworth
- Robarts Research Institute, Western University, London, ON, N6A 5B7, Canada.,Departments of Surgery, and Medical Biophysics, Western University, London, ON, N6A 3K7, Canada
| | - James C Lacefield
- Robarts Research Institute, Western University, London, ON, N6A 5B7, Canada.,Departments of Electrical and Computer Engineering, and Medical Biophysics, Western University, London, ON, N6A 3K7, Canada
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