Dr. Venkataramanan Krishnaswamy Profile

Dr. Venkataramanan Krishnaswamy

Research Associate at Thayer School of Engg at Dartmouth

SPIE Involvement:

Author

Publications (35)

SPIE Journal Paper | 2 January 2018

Algorithm development for intrafraction radiotherapy beam edge verification from Cherenkov imaging

Clare Snyder, Brian Pogue, Michael Jermyn, Irwin Tendler, Jacqueline Andreozzi, Petr Bruza, Venkat Krishnaswamy, David Gladstone, Lesley Jarvis

JMI, Vol. 5, Issue 01, 015001, (January 2018) https://doi.org/10.1117/12.10.1117/1.JMI.5.1.015001

KEYWORDS: Image filtering, Image processing, Radiotherapy, Digital filtering, Binary data, Breast, Algorithm development, Imaging systems, Beam shaping, Image quality

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Proceedings Article | 19 April 2017 Presentation

Sub-diffusive spatial frequency domain imaging: light scattering as a biomarker (Conference Presentation)

David McClatchy, Elizabeth Rizzo, Stephen Kanick, Venkataramanan Krishnaswamy, Jonathan Elliott, Wendy Wells, Keith Paulsen, Brian Pogue

Proceedings Volume 10049, 1004906 (2017) https://doi.org/10.1117/12.2252589

KEYWORDS: Scattering, Light scattering, Tissue optics, Tissues, Modulation, Reflectivity, Breast, Tumor growth modeling, Statistical analysis, Optical properties

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Proceedings Article | 15 February 2017 Presentation + Paper

Combined multispectral spatial frequency domain imaging and computed tomography system for intraoperative breast tumor margin assessment

D. McClatchy, E. Rizzo, V. Krishnaswamy, S. Kanick, W. Wells, K. Paulsen, B. Pogue

Proceedings Volume 10057, 100570H (2017) https://doi.org/10.1117/12.2252626

KEYWORDS: Imaging systems, X-ray computed tomography, Breast, Light scattering, Computing systems, Visualization, Computed tomography, Surgery, Breast cancer, Multimodal imaging, Tissue optics, Tumors, Tissues, X-rays

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SPIE Journal Paper | 27 September 2016 Open Access

Effects of breast density and compression on normal breast tissue hemodynamics through breast tomosynthesis guided near-infrared spectral tomography

Kelly Michaelsen, Venkataramanan Krishnaswamy, Linxi Shi, Srinivasan Vedantham, Andrew Karellas, Brian Pogue, Keith Paulsen, Steven Poplack

JBO, Vol. 21, Issue 09, 091316, (September 2016) https://doi.org/10.1117/12.10.1117/1.JBO.21.9.091316

KEYWORDS: Breast, Tissue optics, Digital breast tomosynthesis, Oxygen, Tissues, Image compression, Imaging systems, Scattering, Sensors, Hemodynamics

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SPIE Journal Paper | 22 April 2015 Open Access

Molecular dyes used for surgical specimen margin orientation allow for intraoperative optical assessment during breast conserving surgery

David McClatchy, Venkataramanan Krishnaswamy, Stephen Kanick, Jonathan Elliott, Wendy Wells, Richard Barth, Keith Paulsen, Brian Pogue

JBO, Vol. 20, Issue 04, 040504, (April 2015) https://doi.org/10.1117/12.10.1117/1.JBO.20.4.040504

KEYWORDS: Tissue optics, Near infrared, Breast, Surgery, Tumors, Tissues, Absorption, Imaging systems, Scattering, Laser sintering

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Proceedings Article | 4 March 2015 Paper

Multispectral reflectance enhancement for breast cancer visualization in the operating room

Gaspar Fernandez-Barreras, Eusebio Real, Ashley Laughney, Venkataramanan Krishnaswamy, Keith Paulsen, José López-Higuera, Brian Pogue, Olga Conde

Proceedings Volume 9311, 931106 (2015) https://doi.org/10.1117/12.2078774

KEYWORDS: Tissues, Reflectivity, Scattering, Tumors, Breast, Visualization, Surgery, Image enhancement, Absorption, Breast cancer

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Proceedings Article | 4 March 2015 Paper

High spatial frequency structured light imaging for intraoperative breast tumor margin assessment

David McClatchy, Venkataramanan Krishnaswamy, Stephen Kanick, Jonathan Elliott, Wendy Wells, Richard Barth, Keith Paulsen, Brian Pogue

Proceedings Volume 9313, 931308 (2015) https://doi.org/10.1117/12.2080134

KEYWORDS: Breast, Spatial frequencies, Tissues, Tumors, Blood, Absorption, Light scattering, Scattering, Mammography, Structured light

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SPIE Journal Paper | 24 July 2014 Open Access

Structured light scatteroscopy

Venkataramanan Krishnaswamy, Jonathan Elliott, David McClatchy, Richard Barth, Wendy Wells, Brian Pogue, Keith Paulsen

JBO, Vol. 19, Issue 07, 070504, (July 2014) https://doi.org/10.1117/12.10.1117/1.JBO.19.7.070504

KEYWORDS: Light scattering, Spatial frequencies, Laser sintering, Scattering, Tissues, Absorption, Reflectivity, Blood, Tissue optics, Structured light

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SPIE Journal Paper | 18 February 2014 Open Access

Anthropomorphic breast phantoms with physiological water, lipid, and hemoglobin content for near-infrared spectral tomography

Kelly Michaelsen, Venkataramanan Krishnaswamy, Adele Shenoy, Emily Jordan, Brian Pogue, Keith Paulsen

JBO, Vol. 19, Issue 02, 026012, (February 2014) https://doi.org/10.1117/12.10.1117/1.JBO.19.2.026012

KEYWORDS: Breast, Tissue optics, Imaging systems, Tumors, Tissues, Absorption, Scattering, Near infrared, Light scattering, Blood

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Proceedings Article | 25 March 2013 Paper

Scattering estimation from digital breast tomosynthesis guiding near infrared spectral tomographic reconstruction

Kelly Michaelsen, Venkataramanan Krishnaswamy, Brian Pogue, Steven Poplack, Keith Paulsen

Proceedings Volume 8578, 857811 (2013) https://doi.org/10.1117/12.2002465

KEYWORDS: Scattering, Digital breast tomosynthesis, Breast, Near infrared, X-rays, X-ray imaging, Imaging systems, Tomography, Tissues, Sensors

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SPIE Journal Paper | 22 March 2013 Open Access

System analysis of spatial frequency domain imaging for quantitative mapping of surgically resected breast tissues

Ashley Laughney, Venkataramanan Krishnaswamy, Tyler Rice, David Cuccia, Richard Barth, Bruce Tromberg, Keith Paulsen, Brian Pogue, Wendy Wells

JBO, Vol. 18, Issue 03, 036012, (March 2013) https://doi.org/10.1117/12.10.1117/1.JBO.18.3.036012

KEYWORDS: Scattering, Tissues, Imaging systems, Absorption, Breast, Diffusion, Modulation, Light scattering, Spatial frequencies, Surgery

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Proceedings Article | 21 February 2013 Paper

Fractal analysis of scatter imaging signatures to distinguish breast pathologies

Alma Eguizabal, Ashley Laughney, Venkataramanan Krishnaswamy, Wendy Wells, Keith Paulsen, Brian Pogue, José López-Higuera, Olga Conde

Proceedings Volume 8592, 85920Y (2013) https://doi.org/10.1117/12.2003830

KEYWORDS: Fractal analysis, Tissues, Scattering, Tumors, Principal component analysis, Breast, Reflectivity, Tumor growth modeling, Pathology, Statistical modeling

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Proceedings Article | 21 February 2013 Paper

Linear classifier and textural analysis of optical scattering images for tumor classification during breast cancer extraction

Alma Eguizabal, Ashley Laughney, Pilar Beatriz Garcia Allende, Venkataramanan Krishnaswamy, Wendy Wells, Keith Paulsen, Brian Pogue, José López-Higuera, Olga Conde

Proceedings Volume 8592, 85920E (2013) https://doi.org/10.1117/12.2003814

KEYWORDS: Tissues, Scattering, Tissue optics, Diagnostics, Breast cancer, Light scattering, Statistical analysis, Tumors, Surgery, Mie scattering

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Proceedings Article | 2 February 2012 Paper

Enhanced tumor contrast during breast lumpectomy provided by independent component analysis of localized reflectance measures

Alma Eguizabal, Ashley Laughney, Pilar Beatriz Garcia Allende, Venkataramanan Krishnaswamy, Wendy Wells, Keith Paulsen, Brian Pogue, Jose Lopez-Higuera, Olga Conde

Proceedings Volume 8230, 823010 (2012) https://doi.org/10.1117/12.909348

KEYWORDS: Independent component analysis, Tissues, Scattering, Reflectivity, Breast, Principal component analysis, Tumors, Model-based design, Statistical analysis, Diagnostics

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Proceedings Article | 2 February 2012 Paper

Blind breast tissue diagnosis using independent component analysis of localized backscattering response

Alma Eguizabal, Ashley Laughney, Pilar Beatriz García Allende, Venkataramanan Krishnaswamy, Wendy Wells, Keith Paulsen, Brian Pogue, Jose Lopez-Higuera, Olga Conde

Proceedings Volume 8230, 823014 (2012) https://doi.org/10.1117/12.909326

KEYWORDS: Independent component analysis, Scattering, Tissues, Breast, Mie scattering, Tissue optics, Reflectivity, Diagnostics, Surgery, Pathology

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Proceedings Article | 1 March 2011 Paper

High frame-rate MR-guided near-infrared tomography system to monitor breast hemodynamics

Zhiqiu Li, Shudong Jiang, Venkataramanan Krishnaswamy, Scott Davis, Subhadra Srinivasan, Keith Paulsen, Brian Pogue

Proceedings Volume 7896, 78962M (2011) https://doi.org/10.1117/12.875839

KEYWORDS: Breast, Near infrared, Tissues, Imaging systems, Magnetic resonance imaging, Tomography, Sensors, Hemodynamics, Interfaces, Signal detection

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Proceedings Article | 1 March 2011 Paper

Continuous-wave and frequency domain optimization in breast tomosynthesis-guided diffuse spectroscopy

Kelly Michaelsen, Venkataramanan Krishnaswamy, Brian Pogue, Keith Paulsen

Proceedings Volume 7896, 78962K (2011) https://doi.org/10.1117/12.875817

KEYWORDS: Tissues, Scattering, Chromophores, Image segmentation, Sensors, Breast, Digital breast tomosynthesis, Tumors, Near infrared, Spectroscopy

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Proceedings Article | 12 February 2011 Paper

Optical assessment of pathology in surgically resected tissues

Ashley Laughney, Venkataramanan Krishnaswamy, Wendy Wells, Olga Conde, Keith Paulsen, Brian Pogue

Proceedings Volume 7907, 79070P (2011) https://doi.org/10.1117/12.874059

KEYWORDS: Tissues, Scattering, Pathology, Spectroscopy, Modulation, Imaging spectroscopy, Tissue optics, Absorption, Breast, Tumors

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Proceedings Article | 12 February 2011 Paper

A dark-field scanning spectroscopy platform for localized scatter and fluorescence imaging of tissue

Venkataramanan Krishnaswamy, Ashley Laughney, Keith Paulsen, Brian Pogue

Proceedings Volume 7907, 79070J (2011) https://doi.org/10.1117/12.875462

KEYWORDS: Spectroscopy, Luminescence, Fluorescence spectroscopy, Tissue optics, Imaging spectroscopy, Imaging systems, Tissues, Molecular spectroscopy, Absorption, Spectroscopes

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Proceedings Article | 11 February 2011 Paper

Assessment of biophysical tumor response to PDT in pancreatic cancer using localized reflectance spectroscopy

Martin Isabelle, William Klubben, Ting He, Ashley Laughney, Adam Glaser, Venkataramanan Krishnaswamy, P. Jack Hoopes, Tayyaba Hasan, Brian Pogue

Proceedings Volume 7886, 78860S (2011) https://doi.org/10.1117/12.876147

KEYWORDS: Tissues, Tumors, Photodynamic therapy, Tissue optics, Reflectivity, Inflammation, Imaging systems, Chromophores, Absorbance, Reflectance spectroscopy

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Biophysical changes such as inflammation and necrosis occur immediately following PDT and may be used to assess the treatment response to PDT treatment in-vivo. This study uses localized reflectance measurements to quantify the scatter changes in tumor tissue occurring in response to verteporfin-based PDT treatment in xenograft pancreas tumors. Nude mice were implanted with subcutaneous AsPC-1 pancreatic tumors cells in matrigel, and allowed to establish solid tumors near 100mm3 volume. The mice were sensitized with 1mg/kg of the active component of verteporfin (benzoporphryin derivative, BPD), one hour before light delivery. The optical irradiation was performed using a 1 cm cylindrical interstitial diffusing tip fiber with 20J of red light (690nm). Tumor tissue was excised progressively and imaged, from 1 day to 4 weeks, after PDT treatment. The tissue sections were stained and analyzed by an expert veterinary pathologist, who provided information on tissue regions of interest. This information was correlated with variations in scattering and absorption parameters elucidated from the spectral images and the degree of necrosis and inflammation involvement was identified. Areas of necrosis and dead cells exhibited the lowest average scatter irradiance signature (3.78 and 4.07 respectively) compared to areas of viable pancreatic tumor cells and areas of inflammation (5.81 and 7.19 respectively). Bilirubin absorbance parameters also showed a lower absorbance value in necrotic tissue and areas of dead cells (0.05 and 0.1 respectively) compared to tissue areas for viable pancreatic tumor cells and areas of inflammation (0.28 and 0.35). These results demonstrate that localized reflectance spectroscopy is an imaging modality that can be used to identify tissue features associated with PDT treatment (e.g. necrosis and inflammation) that can be correlated with histopathologically-reviewed H&E stained slides. Further study of this technique may provide means for automated discrimination of tissue features based on scatter and absorbance maps elucidated from reflectance spectral datasets and provide a valuable tool for treatment response monitoring during PDT and enabling more effective treatment planning. These results are relevant to verteporfin-based PDT trial for treatment pancreatic cancer in non-surgical candidate cases (VERTPAC-1 University College London, PI Pereira), where individualized assessment of damage and response could be beneficial, if this study is proven to be a well-controlled imaging tool.

SPIE Journal Paper | 1 November 2010 Open Access

Automated classification of breast pathology using local measures of broadband reflectance

Ashley Laughney, Venkataramanan Krishnaswamy, Pilar Beatriz García-Allende, Olga Conde, Wendy Wells, Keith Paulsen, Brian Pogue

JBO, Vol. 15, Issue 06, 066019, (November 2010) https://doi.org/10.1117/12.10.1117/1.3516594

KEYWORDS: Tissues, Pathology, Scattering, Breast, Tissue optics, Reflectivity, Surgery, Diagnostics, Light scattering, Error analysis

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Proceedings Article | 17 May 2010 Paper

Automated ensemble segmentation of epithelial proliferation, necrosis, and fibrosis using scatter tumor imaging

P. Beatriz Garcia-Allende, Olga Conde, Venkataramanan Krishnaswamy, P. Jack Hoopes, Brian Pogue, Jesus Mirapeix, Jose Lopez-Higuera

Proceedings Volume 7715, 77151B (2010) https://doi.org/10.1117/12.854559

KEYWORDS: Tumors, Tissues, Scattering, Image segmentation, Imaging systems, Artificial neural networks, Absorption, Tissue optics, Algorithm development, Reflectivity

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SPIE Journal Paper | 1 March 2010 Open Access

System development for high frequency ultrasound-guided fluorescence quantification of skin layers

Josiah Gruber, Akshat Paliwal, Venkat Krishnaswamy, Hamid Ghadyani, Michael Jermyn, Julie O'Hara, Scott Davis, Joanna Kerley-Hamilton, Nicholas Shworak, Edward Maytin, Tayyaba Hasan, Brian Pogue

JBO, Vol. 15, Issue 02, 026028, (March 2010) https://doi.org/10.1117/12.10.1117/1.3374040

KEYWORDS: Luminescence, Tumors, Skin, Image segmentation, Ultrasonography, Tissues, Imaging systems, Signal detection, In vivo imaging, Fluorescence tomography

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Proceedings Article | 10 July 2009 Paper

Video-rate near-infrared tomography using spectral analysis for hemodynamic imaging

Min-Chun Pan, Venkataramanan Krishnaswamy, Subhadra Srinivasan, Brian Pogue

Proceedings Volume 7369, 73691Q (2009) https://doi.org/10.1117/12.831676

KEYWORDS: Hemodynamics, Near infrared, Absorption, Imaging systems, Tomography, Feature extraction, Video, Tumors, Optical tomography, Tissues

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Proceedings Article | 8 July 2009 Paper

Automated interpretation of scatter signatures aimed at tissue morphology identification

P. B. Garcia-Allende, V. Krishnaswamy, K. Samkoe, P. J. Hoopes, B. Pogue, O. Conde, J. López-Higuera

Proceedings Volume 7368, 73681C (2009) https://doi.org/10.1117/12.831561

KEYWORDS: Tumors, Tissues, Scattering, Reflectivity, Imaging systems, Neurons, Image segmentation, Artificial neural networks, Surgery, Scatter measurement

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SPIE Journal Paper | 1 May 2009 Open Access

Automated identification of tumor microscopic morphology based on macroscopically measured scatter signatures

Pilar Beatriz Garcia-Allende, Venkat Krishnaswamy, P. Jack Hoopes, Kimberley Samkoe, Olga Conde, Brian Pogue

JBO, Vol. 14, Issue 03, 034034, (May 2009) https://doi.org/10.1117/12.10.1117/1.3155512

KEYWORDS: Tumors, Tissues, Scattering, Image segmentation, Error analysis, Scatter measurement, Reflectivity, Imaging systems, Absorption, Surgery

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Proceedings Article | 24 February 2009 Paper

Automated segmentation based upon remitted scatter spectra from pathologically distinct tumor regions

Pilar Beatriz Garcia-Allende, Venkataramanan Krishnaswamy, Kimberley Samkoe, P. Jack Hoopes, Brian Pogue, Olga Conde, Jose Lopez-Higuera

Proceedings Volume 7187, 718717 (2009) https://doi.org/10.1117/12.808322

KEYWORDS: Tissues, Tumors, Scattering, Image segmentation, Statistical analysis, Imaging systems, Absorption, Error analysis, Visualization, Pathology

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Proceedings Article | 24 February 2009 Paper

A multi-spectral dark-field reflectance microscope for tumor margin delineation during breast lumpectomy

Venkataramanan Krishnaswamy, Wendy Wells, Ashley Laughney, Kimberley Samkoe, Brian Pogue

Proceedings Volume 7187, 718710 (2009) https://doi.org/10.1117/12.809193

KEYWORDS: Light scattering, Imaging systems, Scattering, Tissue optics, Reflectivity, Mirrors, Tissues, Zemax, Tumors, Breast

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Proceedings Article | 18 February 2009 Paper

System for fluorescence quantification of thin tissue layers guided by high frequency ultrasound

Josiah Gruber, Venkataramanan Krishnaswamy, Edward Maytin, Tayyaba Hasan, Brian Pogue

Proceedings Volume 7164, 71640N (2009) https://doi.org/10.1117/12.809011

KEYWORDS: Luminescence, Spectroscopy, Tissues, Ultrasonography, Calibration, Skin, Optical filters, Sensors, Tissue optics, Tumors

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Proceedings Article | 12 February 2009 Paper

Video-rate near infrared tomography for imaging thick tissue with dynamically varying absorption properties

Zhiqiu Li, Venkataramanan Krishnaswamy, Keith Paulsen, Brian Pogue

Proceedings Volume 7174, 71742G (2009) https://doi.org/10.1117/12.809875

KEYWORDS: Imaging systems, Charge-coupled devices, Tomography, Sensors, Tissues, Near infrared, Optical fibers, Signal detection, Tissue optics, Absorption

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Proceedings Article | 12 February 2009 Paper

Biophysical interpretation and ex-vivo characterization of scattered light from tumor-associated breast stroma

Ashley Laughney, Venkat Krishnaswamy, Mary Schwab, Wendy Wells, Keith Paulsen, Brian Pogue

Proceedings Volume 7174, 71741Y (2009) https://doi.org/10.1117/12.808323

KEYWORDS: Tissues, Collagen, Breast, Phase contrast, Tissue optics, Tumors, Reflectance spectroscopy, Transmission electron microscopy, Diagnostics, Microscopy

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SPIE Journal Paper | 1 January 2009 Open Access

Quantitative imaging of scattering changes associated with epithelial proliferation, necrosis, and fibrosis in tumors using microsampling reflectance spectroscopy

Venkataramanan Krishnaswamy, P. Jack Hoopes, Kimberley Samkoe, Julia O'Hara, Tayyaba Hasan, Brian Pogue

JBO, Vol. 14, Issue 01, 014004, (January 2009) https://doi.org/10.1117/12.10.1117/1.3065540

KEYWORDS: Tumors, Tissues, Scattering, Imaging systems, Absorption, Prostate, Pancreas, Blood, Reflectivity, Confocal microscopy

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Proceedings Article | 22 February 2008 Paper

A raster scanning reflectance imager for non-model based quantification of tissue scatter

Venkataramanan Krishnaswamy, P. Jack Hoopes, Kimberley Samkoe, Brian Pogue

Proceedings Volume 6864, 686402 (2008) https://doi.org/10.1117/12.761780

KEYWORDS: Tissues, Imaging systems, Tumors, Blood, Reflectivity, Scattering, Absorption, Tissue optics, Raster graphics, Ocean optics

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Proceedings Article | 20 February 2008 Paper

System design for spectrally encoded video-rate near infrared tomography during magnetic resonance imaging of the breast

Brian Pogue, Zhiqiu Li, Colin Carpenter, Ashley Laughney, Venkataramanan Krishnaswamy, Scott Davis, Shudong Jiang, Keith Paulsen

Proceedings Volume 6850, 68500H (2008) https://doi.org/10.1117/12.778326

KEYWORDS: Breast, Magnetic resonance imaging, Spectroscopy, Sensors, Tissues, Tomography, Breast imaging, Near infrared, Light, Imaging systems

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Proceedings Article | 13 June 2001 Paper

Measurement of the transmission and reflection Mueller matrices of a thin blood column

Arthur Lompado, Matthew Smith, Venkataramanan Krishnaswamy

Proceedings Volume 4263, (2001) https://doi.org/10.1117/12.429335

KEYWORDS: Blood, Polarization, Polarimetry, Mueller matrices, Reflection, Matrices, Tissue optics, Optical components, Blood vessels, Statistical analysis

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