Digital breast tomosynthesis-guided biopsy: preliminary experience

Transcription

1 Digital breast tomosynthesis-guided biopsy: preliminary experience Poster No.: C-2207 Congress: ECR 2016 Type: Authors: Keywords: DOI: Scientific Exhibit F. Pipan, E. Cimino, E. Zanelli, A. Dal Col, R. Girometti, C. Zuiani, M. Bazzocchi; Udine/IT Breast, Mammography, Biopsy, Comparative studies, Multidisciplinary cancer care /ecr2016/C-2207 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 12

2 Aims and objectives Digital Breast Tomosynthesis (DBT) reduces anatomic noise and the so-called "masking effect" of overlapping tissues by allowing a sequential analysis of thin breast sections through the reconstruction of images in multiple projections. This is why DBT is useful in particular in the identification of masses and architectural distortions [1]. A study by Kopans et al. states that, when compared with standard mammography, DBT is able to show calcifications with greater clarity and may improve the interpretive analysis of detected calcifications [2]. Lesions, which are only or best visualized on tomosynthesis, may undergo stereotactic biopsy under tomosynthesis guidance [3]. DBT-guided biopsy is likely to help expand the number of mammographic lesions that are considered manageable with mammographic Vacuum Assisted Breast Biopsy (VABB) [4]. The aim of this study is to describe our preliminary experience with digital breast tomosynthesis guided vacuum assisted biopsy (DBT-VABB) and compare it to standard stereotactic guidance (SS-VABB). Methods and materials In this prospective study, from March to September 2015, all patients with BI-RADS #3 lesions (assessed according to ACR Breast Imaging Reporting and Data System) [5], not visible with ultrasound, were randomly addressed to DBT-VABB or ss-vabb. Examinations were interpreted by a pool of expert radiologists with at least 10 years of experience and the lesions were scored from 1 to 4, where 1-2 were considered as low contrast lesions (and included masses, asymmetries and architectural distortions) and 3-4 were considered as high contrast lesions (and represented essentially calcifications). SS-VABB was performed with the patient in a prone position on a dedicated prone table unit ( Fig. 1 on page 3 b). The breast was compressed using a dedicated fenestrated compression plate (fenestration of 5x5 cm) and then the lesion was identified and placed in its center. Once the lesion was highlighted in the first mammogram at 0 degrees and in two additional projections at +15 and -15 degrees, the center of the lesion was marked and the spatial coordinates were calculated [6]. Page 2 of 12

3 DBT-VABB was performed with a full-field digital mammography system equipped with a three-dimensional tomosynthesis platform, with a dedicated guidance system add-on. The full detector field (with a biopsy window dependent on the type of paddle that was used for compression) was used [4]. The tomosynthesis image defined directly the depth of the lesion, by finding the Z slice where the lesion was located [7]. The patient was positioned in a sitting position on a dedicated armchair or in a lateral decubitus ( Fig. 1 on page 3 a). In both systems, the following projections were acquired: - images to localize the target lesion ( Fig. 2 on page 4 ); - projection after the local anesthesia to verify that the target has not been displaced; - pre-fire projection to verify the correct targeting ( Fig. 3 on page 5 ; Fig. 4 on page 6 ); - post-fire projection, after inserting the needle into the calculated coordinates, to assure that the window of the needle is placed near the lesion ( Fig. 3 on page 5 ; Fig. 4 on page 6 ); Post-biopsy control was performed to evaluate clip position in patients with non-calcified lesions or in patients with few or no residual micro-calcifications. Biopsies were performed with 9 (DBT-VABB) or 10 (SS-VABB) Gauge vacuum assisted devices through the shortest access to the target lesions and 12 cores were obtained. Following end-points were compared: mean time for lesion targeting (minutes) and number of exposures, both calculated from the first image to localize the target lesion to the post-fire projection. Number of suspended procedures and causes of the interruption were evaluated in both groups. Chi square and Student t tests were used to compare biopsy time, number of exposures and lesion type distribution for DBT versus SS VABB. Images for this section: Page 3 of 12

4 Fig. 1: a) patient undergoing DBT VABB in lateral decubitus position b) Prone stereotactic biopsy table. The target breast lie pendant through the aperture in the table. The physician and technologist work under the table. Institute of Radiology, University Hospital of Udine - Udine/IT Page 4 of 12

5 Fig. 2: SS-VABB' s images to localize the target lesion: first mammogram at 0 degrees (a) and two additional projections at +15 (b) and -15 degrees(c) Institute of Radiology, University Hospital of Udine - Udine/IT Page 5 of 12

6 Fig. 3: SS-VABB's pre-fire and post-fire radiographs at -15 (additional projections at +15 has been acquired). Institute of Radiology, University Hospital of Udine - Udine/IT Page 6 of 12

7 Fig. 4: DBT-VABB's pre-fire and post-fire images. Institute of Radiology, University Hospital of Udine - Udine/IT Page 7 of 12

8 Results Of a total of 111 patients (mean age 58 years for both groups; range 41-79), 54 were addressed to DBT-VABB and 57 to SS-VABB. In the 2 groups lesions contrast was as follows: Category 1-2: 19% (9/48) DBT-VABB 4% (2/48) SS-VABB Category 3-4: 81% (39/48) DBT-VABB 96% (46/48) SS-VABB with a statistically significant difference between two groups (p<0,05). For further endpoints results were as follows: Meantime: 14.5 minutes (± 6 minutes) for DBT-VABB and 25.4 minutes (± 8 minutes) for SS-VABB, with a statistically significant difference between two groups (p<0,05); Number of exposures: 7.2 (± 1.8) for DBT-VABB and 11 (±3.5) for SS-VABB with a statistically significant difference between two groups (p<0,05); Number of suspended procedures: 11% (6/54) in DBT-VABB vs 16% (9/57) in SS-VABB without a statistically significant difference between two groups because of sample skimpiness. In Fig. 5 on page 9 and in Fig. 6 on page 9 we illustrate rispectively one case of fine linear branching micro-calcifications localized at the passage between the inner quadrants and one case of architectural distortion localized at the passage between the external quadrants. In both groups, the main reasons for the suspension of the procedure were: inadequate breast thickness, pre-pectoral or superficial location of the lesion and vasovagal reaction. Page 8 of 12

9 Images for this section: Fig. 5: cranio caudal (a) and mediolateral oblique (b) digital mammograms of the left breast demonstrate fine linear branching micro-calcifications localized at the passage between the inner quadrants. Institute of Radiology, University Hospital of Udine - Udine/IT Page 9 of 12

10 Fig. 6: conventional mammograms (a,b) and DBT images (c,d) that magnify architectural distortion. Institute of Radiology, University Hospital of Udine - Udine/IT Page 10 of 12

11 Conclusion DBT-VABB has been demonstrated to be an accurate and efficient method of sampling lesions identified at DBT [8], especially masses and architectural distortions [4], which may be hardly visible and difficult to target with SS-VABB. Using DBT-VABB, it is possible to increase the number of lesions amenable to mammography-guided biopsy. DBT allows to visualize and exactly localize lesions in the breast, to determine with precision depth and safety margin for the biopsy, and to define the approach (lateral or sitting position) [7]. The use of full detector greatly facilitates lesion re-identification and targeting as compared to the small biopsy window used in the standard stereotactic VABB [4]. The determination of the lesion's depth (Z) directly from tomosynthesis images allows to make the procedure faster and use a smaller number of projections for centering the lesion. Possible disadvantages of DBT-VABB are patient's discomfort and increased radiation dose. In previous studies [4] sitting position is more frequently associated with vasovagal reaction compared to prone position. However these problems are compensated by a shorter procedure. In reference to the procedure's suspension causes, no statistically significant differences were observed in the two procedures in our study. In DBT the radiation dose is slightly higher but the number of exposures needed is lesser. DBT-VABB is useful to reduce the duration of procedures, the number of exposures and allows to detect better than SS-VABB low contrast lesions. DBT-VABB is likely to replace SS-VABB for routine use. Personal information francesca.pipan@gmail.com References 1. Diekmann F, Bick U, Breast tomosynthesis Semin Ultrasound CT MR 2011; 32(4): Kopans D, Gavenonis S, Halpern E, Calcifications in the breast and digital breast tomosynthesis. Breast J 2011; 17(6): Page 11 of 12

12 3. Huang M, Adrada B, Candelaria R, Thames D, Dawson D, Stereotactic Breast Biopsy: Pitfalls and Pearls. Breast J 2015; Schrading S, Distelmaier M, Dirrichs T, et al. Digital Breast Tomosynthesisguided Vacuum-assisted Breast Biopsy: Initial Experiences and Comparison with Prone Stereotactic Vacuum-assisted Biopsy. Radiology 2015; 274: American College of Radiology (ACR) Breast Imaging Reporting and Data System Atlas (BIRADS Atlas). V Edition. Reston, Va: American College of Radiology; Ciulisova A et al, False negative cases at stereotactic biopsy: our experience, /ecr2015/C Viala J, Gignier P, Perret B, et al stereotactic vacuum-assisted biopsies on a digital breast 3D-tomosynthesis system. Breast J 2013; 19(1): Kimberly M et al, Suspicious Findings at Digital Breast Tomosynthesis Occult to Conventional Digital Mammography: Imaging Features and Pathology Findings. Breast J 2015; Page 12 of 12