Breast-Lesion Characterization using Textural Features of Quantitative Ultrasound Parametric Maps

© 2017 The Author(s). This study evaluated, for the first time, the efficacy of quantitative ultrasound (QUS) spectral parametric maps in conjunction with texture-analysis techniques to differentiate non-invasively benign versus malignant breast lesions. Ultrasound B-mode images and radiofrequency data were acquired from 78 patients with suspicious breast lesions. QUS spectral-analysis techniques were performed on radiofrequency data to generate parametric maps of mid-band fit, spectral slope, spectral intercept, spacing among scatterers, average scatterer diameter, and average acoustic concentration. Texture-analysis techniques were applied to determine imaging biomarkers consisting of mean, contrast, correlation, energy and homogeneity features of parametric maps. These biomarkers were utilized to classify benign versus malignant lesions with leave-one-patient-out cross-validation. Results were compared to histopathology findings from biopsy specimens and radiology reports on MR images to evaluate the accuracy of technique. Among the biomarkers investigated, one mean-value parameter and 14 textural features demonstrated statistically significant differences (p < 0.05) between the two lesion types. A hybrid biomarker developed using a stepwise feature selection method could classify the legions with a sensitivity of 96%, a specificity of 84%, and an AUC of 0.97. Findings from this study pave the way towards adapting novel QUS-based frameworks for breast cancer screening and rapid diagnosis in clinic

Application of ultrasound spectral analysis for intraocular tissues differentiation

At present time the ultrasound imaging technique is widely used for qualitative evaluation of ocular tissue structure. Differential diagnosis of human eye tumors is one of the most important problems in ophthalmology in dealing with cancer prevention and diagnostics. Simple ultrasonic methods such as A scan and B scan images used in ophthalmology helps to identify intraocular tumors, but does not reflect the microstructure, does not allow them to differentiate. In this paper the new technique for tumours tissue structure evaluation using ultrasound spectral analysis is presented. Based on the obtained results, it can be said that RF ultrasound signals parameters (amplitude envelope, spectrum slope, spectrum intercept and momentary bandwidth) at the healthy tissue area and the area with the intraocular tumor – melanoma and hemangioma statistically are significantly different. This study has shown that the lower amplitude, lower spectral intercept, high spectral slope and high momentary bandwidth are typical for choroidal melanoma if compared with hemangioma or healthy tissues. This allows us to distinguish healthy tissues from the abnormal tumor tissues, to identify and differentiate chorioidal melanoma and hemangioma between each other. Application of spectral analysis using non-invasive ultrasound expert system, reliably reflects tissue microstructure, gives more information about tissue differences, allows to distinguish healthy tissues from the tumor to identify and differentiate tumors between each other

Chemotherapy-Response Monitoring of Breast Cancer Patients Using Quantitative Ultrasound-Based Intra-Tumour Heterogeneities

© 2017 The Author(s). Anti-cancer therapies including chemotherapy aim to induce tumour cell death. Cell death introduces alterations in cell morphology and tissue micro-structures that cause measurable changes in tissue echogenicity. This study investigated the effectiveness of quantitative ultrasound (QUS) parametric imaging to characterize intra-tumour heterogeneity and monitor the pathological response of breast cancer to chemotherapy in a large cohort of patients (n = 100). Results demonstrated that QUS imaging can non-invasively monitor pathological response and outcome of breast cancer patients to chemotherapy early following treatment initiation. Specifically, QUS biomarkers quantifying spatial heterogeneities in size, concentration and spacing of acoustic scatterers could predict treatment responses of patients with cross-validated accuracies of 82 ± 0.7%, 86 ± 0.7% and 85 ± 0.9% and areas under the receiver operating characteristic (ROC) curve of 0.75 ± 0.1, 0.80 ± 0.1 and 0.89 ± 0.1 at 1, 4 and 8 weeks after the start of treatment, respectively. The patients classified as responders and non-responders using QUS biomarkers demonstrated significantly different survivals, in good agreement with clinical and pathological endpoints. The results form a basis for using early predictive information on survival-linked patient response to facilitate adapting standard anti-cancer treatments on an individual patient basis

Quantitative Ultrasound and B-mode Image Texture Features Correlate with Collagen and Myelin Content in Human Ulnar Nerve Fascicles

We investigate the usefulness of quantitative ultrasound (QUS) and B-mode texture features for characterization of ulnar nerve fascicles. Ultrasound data were acquired from cadaveric specimens using a nominal 30 MHz probe. Next, the nerves were extracted to prepare histology sections. 85 fascicles were matched between the B-mode images and the histology sections. For each fascicle image, we selected an intra-fascicular region of interest. We used histology sections to determine features related to the concentration of collagen and myelin, and ultrasound data to calculate backscatter coefficient (-24.89 dB $\pm$ 8.31), attenuation coefficient (0.92 db/cm-MHz $\pm$ 0.04), Nakagami parameter (1.01 $\pm$ 0.18) and entropy (6.92 $\pm$ 0.83), as well as B-mode texture features obtained via the gray level co-occurrence matrix algorithm. Significant Spearman's rank correlations between the combined collagen and myelin concentrations were obtained for the backscatter coefficient (R=-0.68), entropy (R=-0.51), and for several texture features. Our study demonstrates that QUS may potentially provide information on structural components of nerve fascicles

Evaluation of Thiel cadaveric model for MRI-guided stereotactic procedures in neurosurgery

BACKGROUND: Magnetic resonance imaging (MRI)-guided deep brain stimulation (DBS) and high frequency focused ultrasound (FUS) is an emerging modality to treat several neurological disorders of the brain. Developing reliable models to train and assess future neurosurgeons is paramount to ensure safety and adequate training of neurosurgeons of the future. METHODS: We evaluated the use of Thiel cadaveric model to practice MRI-guided DBS implantation and high frequency MRI-guided FUS in the human brain. We performed three training sessions for DBS and five sonications using high frequency MRI-guided FUS in five consecutive cadavers to assess the suitability of this model to use in training for stereotactic functional procedures. RESULTS: We found the brains of these cadavers preserved in an excellent anatomical condition up to 15 months after embalmment and they were excellent model to use, MRI-guided DBS implantation and FUS produced the desired lesions accurately and precisely in these cadaveric brains. CONCLUSION: Thiel cadavers provided a very good model to perform these procedures and a potential model to train and assess neurosurgeons of the future

Quantitative non-destructive evaluation of porous composite materials based on ultrasonic wave propagation

Two complementary ultrasonic techniques for characterizing porosity in fiber-reinforced composite laminates are evaluated. Five uniaxial graphite-fiber/epoxy-matrix composites having a range of 1 to 8 percent volume fraction of solid glass inclusions to model porosity were investigated. In one technique, signal loss was measured in transmission mode and slope of attenuation, obtained from the first order coefficient of a two-parameter polynomial fit about the center frequency of the useful bandwidth, was used as the ultrasonic parameter to characterize the porosity. The results of these transmission mode measurements displayed a good correlation between the volume fraction of porosity and the slope of attenuation. Integrated polar backscatter was used as a second ultrasonic parameter for the characterization of the porosity in these samples. A single transducer insonified the samples and measured the resulting backscatter at a polar angle of 30 deg with respect to the normal of the sample surface with the azimuthal angles centered at 0 deg with respect to the fiber orientation (i.e., along the fibers). Integrated polar backscatter also displayed good correlation with the volume fraction of porosity