Strain histogram analysis for elastography in breast cancer diagnosis

Transcription

1 Strain histogram analysis for elastography in breast cancer diagnosis Poster No.: C-1854 Congress: ECR 2015 Type: Scientific Exhibit Authors: J. F. Carlsen, C. Ewertsen, S. Sletting, M. B. Nielsen; Copenhagen/DK Keywords: Breast, Oncology, Elastography, Ultrasound, Technology assessment, Experimental investigations, Cancer DOI: /ecr2015/C-1854 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 9

2 Aims and objectives Strain elastography is a method to qualitatively assess tumour stiffness, which can be used to evaluate malignancy risk in combination with B-mode imaging [1]. Strain elastography displays tumour stiffness on a colour scale, and different methods of colour semi-quantification have been proposed [2,3]. The aim of this study was to determine whether strain-histograms analysis is feasible in breast tumour diagnosis, and if mean pixel colour values of malignant tumours are different from mean pixel colour values of benign tumours. Methods and materials Strain elastography is an ultrasound-based method, which non-invasively assesses tissue stiffness [1,4]. In breast tumour diagnosis malignant tumours tend to be stiffer than benign tumours, and strain elastography can be used as an adjunct to the Bmode examination in discerning malignant from being neoplasms (Fig. 1) [5]. In strainelastography however, the assessment of tissue stiffness is a measurement of tissue strain, when manual compression is applied with the transducer on the skin of the patient. As the applied compression is not quantified, neither is the resulting tissue strain. Breast tumour stiffness is therefore displayed on a colour scale relative to the surrounding tissue. Strain histograms are bar charts of the colour distribution within an ROI (Fig. 2-5)[6]. In strain elastography tissue stiffness is displayed on a scale consisting of 256 colours from red (soft), through yellow and green (intermediate stiffness) to blue (hard)[7]. For an ROI the mean pixel colour value can be calculated. The mean pixel colour value is representative of the relative stiffness of the tumour, and the depiction of the strain of the tumour is thereby semi-quantified. In this study strain elastography was performed on women with breast tumours referred for ultrasound-guided biopsy. All examinations were performed using a 5-18 MHz transducer and pathology was used as gold-standard. Strain histograms were performed on cine-loops of 10 seconds length. Strain histogram had the elastogram colours on the y-axis, and the number of pixels of each colour on the x-axis. Strain histograms were made by placing circular ROIs within the tumours and displaying the colours within the ROIs as bar charts. Mean ROI colours values for benign and malignant tumours were calculated. Gold standard for final evaluation was histopathology. A t-test was performed to test statistical significance. P<0.05 was chosen as the level of significance. Page 2 of 9

3 Images for this section: Fig. 1: A strain elastogam of a malignant breast tumour (carcinoma). The elastogram is displayed side-by-side with the B-mode image. The strain elastogram colour scale is displayed in the upper left corner, ranging from red (soft) to blue (hard). The tumour is mainly blue, suggesting that it is hard. Page 3 of 9

4 Fig. 2: A strain elastogram of a ductal carcinoma. The ROI placed in the centre of the tumour, is used for strain histogram analysis (Fig 3). All strain images were recorded as 10 s cine-loops. Page 4 of 9

5 Fig. 3: A strain histogram made from ROI in the strain elastogram in Figure 2. The xaxis shows the colour numbers, corresponding to the elastogram colour code displayed below. The y-axis shows the number of pixels of any given colour in the ROI pr 1000 pixels. The mean pixel colour value of this tumour was 190, a value of a relatively hard tumour. The histopathology diagnosis was ductal carcinoma. Page 5 of 9

6 Fig. 4: A strain elastogram of a fibroadenoma. The ROI placed in the centre of the tumour, is used for strain histogram analysis (Fig 5). All strain images were recorded as 10 s cine-loops. Page 6 of 9

7 Fig. 5: A strain histogram made from ROI in the strain elastogram in Figure 4. The xaxis shows the colour numbers, corresponding to the elastogram colour code displayed below. The y-axis shows the number of pixels of any given colour in the ROI pr 1000 pixels. The mean pixel colour value of this tumour was 145, a value of a intermediate stiffness tumour. The histopathology diagnosis was fibroadenoma. Page 7 of 9

8 Results Thirty-six women (Mean age 52 years, range 23-81) with 42 breast tumours were included. Sixteen tumours were benign (Mean diameter 7.9 mm, SD 3.4 mm) and 26 were malignant (Mean diameter 11.2 mm, SD 4.3 mm). Mean histogram values were 176.2, SD 34.1 for benign tumours and 202.2, SD 22.4 for malignant tumours (P=0.002). Conclusion Strain histogram analysis can be performed in breast tumours, and there is significant difference between mean histogram values of benign and malignant tumours. Personal information Jonathan Frederik Carlsen is an M.D. at Dep. of Radiology, Rigshospitalet, Copenhagen University Hospital, Denmark. References 1. Cosgrove D, Piscaglia F, Bamber J, Bojunga J, Correas J-M, Gilja O, et al. EFSUMB Guidelines and Recommendations on the Clinical Use of Ultrasound Elastography.Part 2: Clinical Applications. Ultraschall in Medizin Apr 19; 34(03): Fischer T, Peisker U, Fiedor S, Slowinski T, Wedemeyer P, Diekmann F, et al. Significant Differentiation of Focal Breast Lesions: Raw Data-Based Calculation of Strain Ratio. Ultraschall in Med May 25; 33(04): Itoh A, Ueno E, Tohno E, Kamma H, Takahashi H, Shiina T, et al. Breast Disease: Clinical Application of US Elastography for Diagnosis1. Radiology May 1; 239(2): Bamber J, Cosgrove D, Dietrich CF, Fromageau J, Bojunga J, Calliada F, et al. EFSUMB Guidelines and Recommendations on the Clinical Use of Ultrasound Elastography. Part 1: Basic Principles and Technology. Ultraschall Med Apr; 34(2): Page 8 of 9

9 5. Sadigh G, Carlos R, Neal C, Dwamena B. Accuracy of quantitative ultrasound elastography for differentiation of malignant and benign breast abnormalities: a metaanalysis. Breast Cancer Research and Treatment; Sãftoiu A, S#ftoui A, Gheonea DI, Ciurea T. Hue histogram analysis of real-time elastography images for noninvasive assessment of liver fibrosis. AJR Am J Roentgenol Oct;189(4):W Normal 0 21 false false false DA JA X-NONE 7. Carlsen J, Ewertsen C, Lönn L, Nielsen M. Strain Elastography Ultrasound: An Overview with Emphasis on Breast Cancer Diagnosis. Diagnostics Feb 25; 3(1): Page 9 of 9