Title Page
Contents
Abstract 9
Ⅰ. Introduction 10
Ⅱ. Methods and Materials 14
A. Reverberation artifact in medical ultrasound B-mode imaging 14
B. Experimental setup 16
1) Reverberation artifact phantom 16
2) Data acquisition 18
C. DCL for Reverberation artifact reduction (DCL-Reverb) 19
D. Image evaluation 23
Ⅲ. Results and Discussion 24
A. Results on ex-vivo images 24
B. Results on in-vivo images 28
Ⅳ. Conclusion 31
References 32
Table.1. Results of CNR (dB) and gCNR measured in B-mode images for ex-vivo cyst-shape phantom in Fig.8-(a). The orange and green boxes indicate of the... 27
Table.2. Results of CNR (dB) and gCNR measured in B-mode images of transverse section for ex-vivo carotid-shape phantom in Fig.8-(b). The orange and green boxes... 27
Table.3. Results of CNR (dB) and gCNR measured in B-mode images of longitudinal section for ex-vivo carotid-shape phantom in Fig.8-(c). The orange and green boxes... 27
Table.4. Results of CNR (dB) and gCNR measured in B-mode images for in-vivo carotid artery in Fig.10. The orange and green boxes indicate of the anechoic and... 30
Fig.1. A graphic illustration showing (a) the process by which reverberation artifact occur and (b) the process by which attenuation occurs between organizations. 15
Fig.2. (a) Reverberation artifact seen at evenly spaced echogenic bands beyond a copper intrauterine device. (b) Reverberation artifact seen in the anterior portion of... 15
Fig.3. (a) A cylindrical mold with a diameter of 6 mm and a length of 75 mm was used to produce the carotid-shaped reverberation artifact model. (b) A spherical... 16
Fig.4. A pork phantom with (a) carotid-shape, and (b) cyst-shape for reverberation artifact. (c) The completed reverberation artifact phantom for RF data acquisition. 17
Fig.5. Plane wave images with reverberation artifacts using (a) carotid-shape and (b) cyst-shape phantoms. 18
Fig.6. Schematic representation of the DCL-Reverb framework about (a) training phase and (b) inference phase. 20
Fig.7. CNN based on the U-Net architecture for DCL-Reverb training. 22
Fig.8. Reconstructed B-mode images by DAS, 3DCNN, DCL, and DCL-Reverb from the results scanned in ex-vivo (a) cyst shape, (b) carotid-shape with transverse... 25
Fig.9. Normalized intensity (dB) of axial profiles for four beamforming methods in the yellow arrow scanline from Fig.8-(a), (b), and (c). The red arrow point in the... 26
Fig.10. Reconstructed B-mode images by (a) DAS, (b) 3DCNN, (c) DCL, and (d) DCL-Reverb from the results scanned in in-vivo carotid artery. CNR and gCNR... 29
Fig.11. Normalized intensity (dB) of axial profiles for four beamforming methods in the yellow arrow scanline from Fig.10-(a). The red arrow point in the graph is the... 30