Unspecified Yun Liang Profile

Yun Liang

Associate Professor at Indiana Univ School of Medicine

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Publications (12)

Proceedings Article | 20 March 2006 Paper

Evaluating dynamic contrast-enhanced and photoacoustic CT to assess intra-tumor heterogeneity in xenograft mouse models

Keith Stantz, Bo Liu, Minsong Cao, Dan Reinecke, Mario Dzemidzic, Yun Liang, Robert Kruger

Proceedings Volume 6143, 61431F (2006) https://doi.org/10.1117/12.654056

KEYWORDS: Tumors, Oxygen, Blood, Photoacoustic spectroscopy, Breast, In vivo imaging, Vascular physiology, Calibration, Error analysis, Plasma

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Proceedings Article | 13 March 2006 Paper

Myocardial physiology measurements using contrast enhanced dynamic computed tomography: simulation of beam hardening effect

Minsong Cao, Keith Stantz, Yun Liang

Proceedings Volume 6143, 61432N (2006) https://doi.org/10.1117/12.654206

KEYWORDS: Physiology, Computer simulations, Heart, Iodine, X-ray computed tomography, X-rays, Error analysis, Optical simulations, Scanners, Computed tomography

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Proceedings Article | 14 April 2005 Paper

Assessment of multislice CT to quantify pulmonary emphysema function and physiology in a rat model

Minsong Cao, Keith Stantz, Yun Liang, Ganapathy Krishnamurthi, Robert Presson

Proceedings Volume 5746, (2005) https://doi.org/10.1117/12.595775

KEYWORDS: Lung, Emphysema, Computed tomography, Capillaries, Signal attenuation, Tissues, Animal model studies, Physiology, Image segmentation, Blood

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Proceedings Article | 30 April 2004 Paper

Reproducibility of physiologic parameters obtained using functional computed tomography in mice

Ganapathy Krishnamurthi, Keith Stantz, Rosemary Steinmetz, Gary Hutchins, Yun Liang

Proceedings Volume 5369, (2004) https://doi.org/10.1117/12.536255

KEYWORDS: Tissues, Kidney, Heart, Capillaries, Tumors, Computed tomography, Physiology, Picosecond phenomena, X-ray computed tomography, Iodine

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Proceedings Article | 30 April 2004 Paper

Kinematic modeling and its implication in longitudinal chemotherapy study of tumor physiology: ovarian xenograft mouse model and contrast-enhanced dynamic CT (Honorable Mention Poster Award)

Keith Stantz, Yun Liang, Gary Hutchins

Proceedings Volume 5369, (2004) https://doi.org/10.1117/12.536212

KEYWORDS: Tumors, Error analysis, Picosecond phenomena, Physiology, Computed tomography, Mouse models, Plasma, Scanners, Temporal resolution, Tissues

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The purpose of this study is to demonstrate that dynamic CT provides the necessary sensitivity to quantify tumor physiology and differences in chemotherapeutic response. A compartmental mouse model utilizing measured contrast-enhanced dynamic CT scans is used to simulate systematic and statistical errors associated with tumor physiology: perfusion, permeability (PS), fractional plasma volume (f_p), and fractional interstitial volume. The solute utilized is a small molecular weight radio-opaque contrast agent (isovue). For such an intravascular-interstitial medium, the kinematics simplifies to a two compartmental diffusive dominated set of coupled differential equations. Each combination of physiological parameters is repeatedly simulated fifteen times from which statistical errors calculated. The fractional change relative to the true value (systematic error) and standard deviation (statistical error) are plotted as a function of PS, f_p, scanner temporal resolution and noise, and contrast media injection rates. By extrapolating from experimental data found in literature, a relative change in PS and f_p of approximately 40% is required. Thus, the longitudinal response of two chemotherapeutic drugs under investigation - proteasome and IMPDH inhibitors - are hypothesized to induce different physiological responses. The first set of simulations varies PS from 0.05 to 0.40 mL/min/mL and f_p from 0.01 to 0.07 mL/mL while holding all other physiological parameters constant. Errors in PS remain below 3% while statistical errors for f_p increase significantly as the volume decreases toward 1-2%: errors remain less than 6% for f_p>0.03 while increasing to above 15% for f_p<0.02. The second set of simulations are performed quantifying the relationship between scanner temporal resolution and contrast media injection rate for various tumor permeabilities. For the majority of cases, the errors remain below 5%. As PS approaches perfusion, a total error less than 6% can be maintained for a temporal resolution less than or equal to 3 seconds, and an error less than 9% up to 5-7 seconds. As the injection rate decreases from 2 mL/min down to 0.25 mL/min, inadequate sampling of the contrast dynamics necessary to decouple the physiological parameters is lost increasing both systematic and statistical errors from 10% when sampling at 5 seconds in excess of 20-25% at a 9 second sampling rate. In each case, dynamic CT provides the necessary sensitivity to distinguish between the differing therapeutic reponses of proteasome and IMPDH inhibitors.

Proceedings Article | 2 May 2003 Paper

In-vivo regional myocardial perfusion measurements in a porcine model by ECG-gated multislice computed tomography

Keith Stantz, Yun Liang, Cristopher Meyer, Shawn Teague, Michael Stecker, Gary Hutchins, Gordon McLennan, Scott Persohn

Proceedings Volume 5031, (2003) https://doi.org/10.1117/12.480431

KEYWORDS: Computed tomography, Heart, Positron emission tomography, Arteries, Tissues, Blood, Data modeling, Motion models, Scanners, Blood circulation

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Purpose: To evaluate whether functional multi-slice computed tomography (MSCT) can identify regional areas of normally perfused and ischemic myocardium in a porcine model. Material and Methods: Three out bred pigs, two of which had ameroids surgically implanted to constrict flow within the LAD and LCx coronary arteries, were injected with 25 mL of iopromide (Isovue) at a rate of 5 mL/second via the femoral or jugular vein. Sixty axial scans along the short axis of the heart was acquired on a 16-slice CT scanner (Philips MX8000-IDT) triggered at end-diastole of the cardiac cycle and acquiring an image within 270 msec. A second series of scans were taken after an intravenous injection of a vasodilator, 150 μg/kg/min of adenosine. ROIs were drawn around the myocardial tissue and the resulting time-density curves were used to extract perfusion values. Results: Determination of the myocardial perfusion and fractional blood volume implementing three different perfusion models. A 5-point averaging or 'smoothing' algorithm was employed to effectively filter the data due to its noisy nature. The (preliminary) average perfusion and fractional blood volume values over selected axial slices for the pig without an artificially induced stenosis were measured to be 84 ± 22 mL/min/100g-tissue and 0.17 ± 0.04 mL/g-tissue, the former is consistent with PET scan and EBCT results. The pig with a stenosis in the left LAD coronary artery showed a reduced global perfusion value -- 45 mL/min/100g-tissue. Correlations in regional perfusion values relative to the stenosis were weak. During the infusion of adenosine, averaged perfusion values for the three subjects increased by 46 (±45) percent, comparable to increases measured with PET. Conclusion: Quantifying global perfusion values using MDCT appear encouraging. Future work will focus resolving the systematic effects from noise due to signal fluctuation from the porcine tachyardia (80-93 BPM) and provide a more robust measurement of regional myocardial perfusion throughout the heart.

Proceedings Article | 2 May 2003 Paper

Development of contrast-enhanced rodent imaging using functional CT

Yun Liang, Keith Stantz, Ganapathy Krishnamurthi, Rosemary Steinmetz, Gary Hutchins

Proceedings Volume 5031, (2003) https://doi.org/10.1117/12.480690

KEYWORDS: Tissues, Tumors, Kidney, Physiology, Imaging systems, Scanners, X-ray computed tomography, Computed tomography, Blood, Capillaries

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Proceedings Article | 9 May 2002 Paper

Reproducibility of the coronary calcium measurement with different cardiac algorithms using multislice spiral CT

Yun Liang, Ganapathy Krishnamurthi, Laigao Chen, Cristopher Meyer

Proceedings Volume 4684, (2002) https://doi.org/10.1117/12.467207

KEYWORDS: Calcium, Reconstruction algorithms, Electrocardiography, Temporal resolution, Heart, Computed tomography, Cardiac imaging, Algorithm development, Arteries, Lithium

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Proceedings Article | 9 May 2002 Paper

Novel method for reducing high-attenuation object artifacts in CT reconstructions

Laigao Chen, Yun Liang, George Sandison, Jonas Rydberg

Proceedings Volume 4684, (2002) https://doi.org/10.1117/12.467232

KEYWORDS: Metals, Signal attenuation, X-ray computed tomography, Tissues, X-rays, Digital filtering, Scanners, CT reconstruction, Reconstruction algorithms, Computed tomography

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Proceedings Article | 3 July 2001 Paper

Performance evaluation of oblique surface reconstruction algorithm in multislice cone-beam CT

Laigao Chen, Yun Liang, Dominic Heuscher

Proceedings Volume 4322, (2001) https://doi.org/10.1117/12.430969

KEYWORDS: Reconstruction algorithms, Sensors, Lithium, X-ray computed tomography, X-rays, Image quality, Detection and tracking algorithms, Scanners, Algorithm development, X-ray sources

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Proceedings Article | 16 November 2000 Paper

Oblique surface reconstruction to approximate cone-beam helical data in multislice CT

Laigao Chen, Dominic Heuscher, Yun Liang

Proceedings Volume 4123, (2000) https://doi.org/10.1117/12.409280

KEYWORDS: Reconstruction algorithms, Image quality, X-rays, Lithium, Sensors, X-ray computed tomography, Detector arrays, Scanners, Fluctuations and noise, Collimation

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Proceedings Article | 8 July 1994 Paper

Computerized tomographic angiography image segmentation for 3D-volume reconstruction

Yun Liang, Robert Kruger

Proceedings Volume 2299, (1994) https://doi.org/10.1117/12.179256

KEYWORDS: Image segmentation, Arteries, Angiography, Image processing, Tissues, Bone, X-ray computed tomography, 3D image processing, 3D image reconstruction, Computed tomography

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Showing 5 of 12 publications

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