Christina Yan
Undergraduate Student
School of Computing
Queen's University
Christina started as a freshmen biomedical computing student at Queen's. Her research projects have included ultrasound guided scoliosis monitoring and computer-aided navigation for breast cancer surgery. Having done a full-year industrial internship, she returned to the Perk Lab in Fall 2018 for doing her BSc hon's thesis on develpment of a computer-assisted training system for endoscpic vein harvesting, co-supervised in the Perk Lab and in the Department of Surgery.
Kamali, Shahrokh; Ungi, Tamas; Lasso, Andras; Yan, Christina; Lougheed, Matthew; Fichtinger, Gabor
Localization of the transverse processes in ultrasound for spinal curvature measurement Conference
SPIE Medical Imaging, vol. 10135, 2017.
@conference{Kamali2017a,
title = {Localization of the transverse processes in ultrasound for spinal curvature measurement},
author = {Shahrokh Kamali and Tamas Ungi and Andras Lasso and Christina Yan and Matthew Lougheed and Gabor Fichtinger},
url = {http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=2615387
https://labs.cs.queensu.ca/perklab/wp-content/uploads/sites/3/2024/02/Kamali2017a.pdf},
doi = {10.1117/12.2256007},
year = {2017},
date = {2017-02-01},
urldate = {2017-02-01},
booktitle = {SPIE Medical Imaging},
volume = {10135},
pages = {101350I-101350I-7},
abstract = {<p>PURPOSE: In scoliosis monitoring, tracked ultrasound has been explored as a safer imaging alternative to traditional radiography. The use of ultrasound in spinal curvature measurement requires identification of vertebral landmarks such as transverse processes, but as bones have reduced visibility in ultrasound imaging, skeletal landmarks are typically segmented manually, which is an exceedingly laborious and long process. We propose an automatic algorithm to segment and localize the surface of bony areas in the transverse process for scoliosis in ultrasound.METHODS: The algorithm uses cascade of filters to remove low intensity pixels, smooth the image and detect bony edges. By applying first differentiation, candidate bony areas are classified. The average intensity under each area has a correlation with the possibility of a shadow, and areas with strong shadow are kept for bone segmentation. The segmented images are used to reconstruct a 3-D volume to represent the whole spinal structure around the transverse processes. RESULTS: A comparison between the manual ground truth segmentation and the automatic algorithm in 50 images showed 0.17 mm average difference. The time to process all 1,938 images was about 37 Sec. (0.0191 Sec. / Image), including reading the original sequence file.CONCLUSION: Initial experiments showed the algorithm to be sufficiently accurate and fast for segmentation transverse processes in ultrasound for spinal curvature measurement. An extensive evaluation of the method is currently underway on images from a larger patient cohort and using multiple observers in producing ground truth segmentation.</p>},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
<p>PURPOSE: In scoliosis monitoring, tracked ultrasound has been explored as a safer imaging alternative to traditional radiography. The use of ultrasound in spinal curvature measurement requires identification of vertebral landmarks such as transverse processes, but as bones have reduced visibility in ultrasound imaging, skeletal landmarks are typically segmented manually, which is an exceedingly laborious and long process. We propose an automatic algorithm to segment and localize the surface of bony areas in the transverse process for scoliosis in ultrasound.METHODS: The algorithm uses cascade of filters to remove low intensity pixels, smooth the image and detect bony edges. By applying first differentiation, candidate bony areas are classified. The average intensity under each area has a correlation with the possibility of a shadow, and areas with strong shadow are kept for bone segmentation. The segmented images are used to reconstruct a 3-D volume to represent the whole spinal structure around the transverse processes. RESULTS: A comparison between the manual ground truth segmentation and the automatic algorithm in 50 images showed 0.17 mm average difference. The time to process all 1,938 images was about 37 Sec. (0.0191 Sec. / Image), including reading the original sequence file.CONCLUSION: Initial experiments showed the algorithm to be sufficiently accurate and fast for segmentation transverse processes in ultrasound for spinal curvature measurement. An extensive evaluation of the method is currently underway on images from a larger patient cohort and using multiple observers in producing ground truth segmentation.</p>
Yan, Christina; Ungi, Tamas; Gauvin, Gabrielle; Jabs, Doris; Lasso, Andras; Engel, C. Jay; Rudan, John; Fichtinger, Gabor
Study into the displacement of tumor localization needle during navigated breast cancer surgery Conference
SPIE Medical Imaging, SPIE SPIE, Orlando, Florida, USA, 2017.
@conference{Yan2017a,
title = {Study into the displacement of tumor localization needle during navigated breast cancer surgery},
author = {Christina Yan and Tamas Ungi and Gabrielle Gauvin and Doris Jabs and Andras Lasso and C. Jay Engel and John Rudan and Gabor Fichtinger},
url = {https://labs.cs.queensu.ca/perklab/wp-content/uploads/sites/3/2024/02/Yan2017a_0.pdf},
year = {2017},
date = {2017-01-01},
urldate = {2017-01-01},
booktitle = {SPIE Medical Imaging},
publisher = {SPIE},
address = {Orlando, Florida, USA},
organization = {SPIE},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Yan, Christina; Ungi, Tamas; Gauvin, Gabrielle; Jabs, Doris; Lasso, Andras; Engel, C. Jay; Rudan, John; Fichtinger, Gabor
15th Annual Imaging Network of Ontario (ImNO), 2017.
@conference{Yan2017b,
title = {Quantification of tumor localization needle displacement prior to tumor excision in navigated lumpectomy},
author = {Christina Yan and Tamas Ungi and Gabrielle Gauvin and Doris Jabs and Andras Lasso and C. Jay Engel and John Rudan and Gabor Fichtinger},
url = {https://labs.cs.queensu.ca/perklab/wp-content/uploads/sites/3/2024/02/Yan2017b.pdf
https://labs.cs.queensu.ca/perklab/wp-content/uploads/sites/3/2024/02/Yan-IMNO-v3.pptx},
year = {2017},
date = {2017-01-01},
urldate = {2017-01-01},
booktitle = {15th Annual Imaging Network of Ontario (ImNO)},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Yan, Christina; Tabanfar, Reza; Kempston, Michael; Borschneck, Daniel P.; Ungi, Tamas; Fichtinger, Gabor
Comparison of portable and conventional ultrasound imaging in spinal curvature measurement Conference
SPIE Medical Imaging, SPIE Medical Imaging 2016 SPIE Medical Imaging 2016, San Diego, CA, United States., 2016.
@conference{Yan2016a,
title = {Comparison of portable and conventional ultrasound imaging in spinal curvature measurement},
author = {Christina Yan and Reza Tabanfar and Michael Kempston and Daniel P. Borschneck and Tamas Ungi and Gabor Fichtinger},
url = {https://labs.cs.queensu.ca/perklab/wp-content/uploads/sites/3/2024/02/Yan2016a_1.pdf},
year = {2016},
date = {2016-01-01},
urldate = {2016-01-01},
booktitle = {SPIE Medical Imaging},
publisher = {SPIE Medical Imaging 2016},
address = {San Diego, CA, United States.},
organization = {SPIE Medical Imaging 2016},
abstract = {<p>PURPOSE: In scoliosis monitoring, tracked ultrasound has been explored as a safer imaging alternative to traditional radiography. The use of ultrasound in spinal curvature measurement requires identification of vertebral landmarks, but bones have reduced visibility in ultrasound imaging and high quality ultrasound machines are often expensive and not portable. In this work, we investigate the image quality and measurement accuracy of a low cost and portable ultrasound machine in comparison to a standard ultrasound machine in scoliosis monitoring. </p>
<p> <br />
METHODS: Two different kinds of ultrasound machines were tested on three human subjects, using the same position tracker and software. Spinal curves were measured in the same reference coordinate system using both ultrasound machines. Lines were defined by connecting two symmetric landmarks identified on the left and right transverse process of the same vertebrae, and spinal curvature was defined as the transverse process angle between two such lines, projected on the coronal plane. </p>
<p>RESULTS: Three healthy volunteers were scanned by both ultrasound configurations. Three experienced observers localized transverse processes as skeletal landmarks and obtained transverse process angles in images obtained from both ultrasounds. The mean difference per transverse process angle measured was 3.00 ± 2.1°. 94% of transverse processes visualized in the Sonix Touch were also visible in the Telemed. Inter-observer error in the Telemed was 4.5° and 4.3° in the Sonix Touch. </p>
<p>CONCLUSION: Price, convenience and accessibility suggest the Telemed to be a viable alternative in scoliosis monitoring, however further improvements in measurement protocol and image noise reduction must be completed before implementing the Telemed in the clinical setting. </p>},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
<p>PURPOSE: In scoliosis monitoring, tracked ultrasound has been explored as a safer imaging alternative to traditional radiography. The use of ultrasound in spinal curvature measurement requires identification of vertebral landmarks, but bones have reduced visibility in ultrasound imaging and high quality ultrasound machines are often expensive and not portable. In this work, we investigate the image quality and measurement accuracy of a low cost and portable ultrasound machine in comparison to a standard ultrasound machine in scoliosis monitoring. </p>
<p> <br />
METHODS: Two different kinds of ultrasound machines were tested on three human subjects, using the same position tracker and software. Spinal curves were measured in the same reference coordinate system using both ultrasound machines. Lines were defined by connecting two symmetric landmarks identified on the left and right transverse process of the same vertebrae, and spinal curvature was defined as the transverse process angle between two such lines, projected on the coronal plane. </p>
<p>RESULTS: Three healthy volunteers were scanned by both ultrasound configurations. Three experienced observers localized transverse processes as skeletal landmarks and obtained transverse process angles in images obtained from both ultrasounds. The mean difference per transverse process angle measured was 3.00 ± 2.1°. 94% of transverse processes visualized in the Sonix Touch were also visible in the Telemed. Inter-observer error in the Telemed was 4.5° and 4.3° in the Sonix Touch. </p>
<p>CONCLUSION: Price, convenience and accessibility suggest the Telemed to be a viable alternative in scoliosis monitoring, however further improvements in measurement protocol and image noise reduction must be completed before implementing the Telemed in the clinical setting. </p>
<p> <br />
METHODS: Two different kinds of ultrasound machines were tested on three human subjects, using the same position tracker and software. Spinal curves were measured in the same reference coordinate system using both ultrasound machines. Lines were defined by connecting two symmetric landmarks identified on the left and right transverse process of the same vertebrae, and spinal curvature was defined as the transverse process angle between two such lines, projected on the coronal plane. </p>
<p>RESULTS: Three healthy volunteers were scanned by both ultrasound configurations. Three experienced observers localized transverse processes as skeletal landmarks and obtained transverse process angles in images obtained from both ultrasounds. The mean difference per transverse process angle measured was 3.00 ± 2.1°. 94% of transverse processes visualized in the Sonix Touch were also visible in the Telemed. Inter-observer error in the Telemed was 4.5° and 4.3° in the Sonix Touch. </p>
<p>CONCLUSION: Price, convenience and accessibility suggest the Telemed to be a viable alternative in scoliosis monitoring, however further improvements in measurement protocol and image noise reduction must be completed before implementing the Telemed in the clinical setting. </p>
Tabanfar, Reza; Yan, Christina; Kempston, Michael; Borschneck, Daniel P.; Ungi, Tamas; Fichtinger, Gabor
Clinical feasibility of pediatric scoliosis monitoring using portable ultrasound Conference
Imaging Network Ontario (IMNO), 2016.
@conference{Tabanfar2016,
title = {Clinical feasibility of pediatric scoliosis monitoring using portable ultrasound},
author = {Reza Tabanfar and Christina Yan and Michael Kempston and Daniel P. Borschneck and Tamas Ungi and Gabor Fichtinger},
url = {https://labs.cs.queensu.ca/perklab/wp-content/uploads/sites/3/2024/02/Tabanfar2016b.pdf},
year = {2016},
date = {2016-01-01},
urldate = {2016-01-01},
booktitle = {Imaging Network Ontario (IMNO)},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Yan, Christina; Tabanfar, Reza; Kempston, Michael; Borschneck, Daniel P.; Ungi, Tamas; Fichtinger, Gabor
Vertebral landmark visualization with portable ultrasound imaging in scoliosis monitoring Conference
14th Annual Imaging Network Ontario Symposium (ImNO), 2016.
@conference{Yan2016,
title = {Vertebral landmark visualization with portable ultrasound imaging in scoliosis monitoring},
author = {Christina Yan and Reza Tabanfar and Michael Kempston and Daniel P. Borschneck and Tamas Ungi and Gabor Fichtinger},
url = {https://labs.cs.queensu.ca/perklab/wp-content/uploads/sites/3/2024/02/Yan2016b.pdf},
year = {2016},
date = {2016-01-01},
urldate = {2016-01-01},
booktitle = {14th Annual Imaging Network Ontario Symposium (ImNO)},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Tabanfar, Reza; Yan, Christina; Kempston, Michael; Borschneck, Daniel; Ungi, Tamas; Fichtinger, Gabor
Clinical workflow for spinal curvature measurement with portable ultrasound Journal Article
In: vol. 9786, pp. 149-154, 2016.
@article{fichtinger2016p,
title = {Clinical workflow for spinal curvature measurement with portable ultrasound},
author = {Reza Tabanfar and Christina Yan and Michael Kempston and Daniel Borschneck and Tamas Ungi and Gabor Fichtinger},
url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9786/97860G/Clinical-workflow-for-spinal-curvature-measurement-with-portable-ultrasound/10.1117/12.2217249.short},
year = {2016},
date = {2016-01-01},
volume = {9786},
pages = {149-154},
publisher = {SPIE},
abstract = {PURPOSE
Spinal curvature monitoring is essential in making treatment decisions in scoliosis. Monitoring entails radiographic examinations, however repeated ionizing radiation exposure has been shown to increase cancer risk. Ultrasound does not emit ionizing radiation and is safer for spinal curvature monitoring. We investigated a clinical sonography protocol and challenges associated with position-tracked ultrasound in spinal curvature measurement in scoliosis.
METHODS
Transverse processes were landmarked along each vertebra using tracked ultrasound snapshots. The transverse process angle was used to determine the orientation of each vertebra. We tested our methodology on five patients in a local pediatric scoliosis clinic, comparing ultrasound to radiographic curvature measurements.
RESULTS
Despite strong correlation between radiographic and ultrasound curvature angles in phantom studies …},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
PURPOSE
Spinal curvature monitoring is essential in making treatment decisions in scoliosis. Monitoring entails radiographic examinations, however repeated ionizing radiation exposure has been shown to increase cancer risk. Ultrasound does not emit ionizing radiation and is safer for spinal curvature monitoring. We investigated a clinical sonography protocol and challenges associated with position-tracked ultrasound in spinal curvature measurement in scoliosis.
METHODS
Transverse processes were landmarked along each vertebra using tracked ultrasound snapshots. The transverse process angle was used to determine the orientation of each vertebra. We tested our methodology on five patients in a local pediatric scoliosis clinic, comparing ultrasound to radiographic curvature measurements.
RESULTS
Despite strong correlation between radiographic and ultrasound curvature angles in phantom studies …
Spinal curvature monitoring is essential in making treatment decisions in scoliosis. Monitoring entails radiographic examinations, however repeated ionizing radiation exposure has been shown to increase cancer risk. Ultrasound does not emit ionizing radiation and is safer for spinal curvature monitoring. We investigated a clinical sonography protocol and challenges associated with position-tracked ultrasound in spinal curvature measurement in scoliosis.
METHODS
Transverse processes were landmarked along each vertebra using tracked ultrasound snapshots. The transverse process angle was used to determine the orientation of each vertebra. We tested our methodology on five patients in a local pediatric scoliosis clinic, comparing ultrasound to radiographic curvature measurements.
RESULTS
Despite strong correlation between radiographic and ultrasound curvature angles in phantom studies …