In vivo endoscopic Doppler optical coherence tomography imaging of the colon

Weston A. Welge, Jennifer K Barton

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Background and Objective: Colorectal cancer (CRC) remains the second deadliest cancer in the United States. Several screening methods exist; however, detection of small polyps remains a challenge. Optical coherence tomography (OCT) has been demonstrated to be capable of detecting lesions as small as 1 mm in the mouse colon, but detection is based on measuring a doubling of the mucosa thickness. The colon microvasculature may be an attractive biomarker of early tumor development because tumor vessels are characterized by irregular structure and dysfunction. Our goal was to develop an endoscopic method of detecting and segmenting colon vessels using Doppler OCT to enable future studies for improving early detection and development of novel chemopreventive agents. Method: We conducted in vivo colon imaging in an azoxymethane (AOM)-treated mouse model of colorectal cancer using a miniature endoscope and a swept-source OCT system at 1,040 nm with a 16 kHz sweep rate. We applied the Kasai autocorrelation algorithm to laterally oversampled OCT B-scans to resolve vascular flow in the mucosa and submucosa. Vessels were segmented by applying a series of image processing steps: (i) intensity thresholding; (ii) two-dimensional matched filtering; and (iii) histogram segmentation. Results: We observed differences in the vessels sizes and spatial distribution in a mature adenoma compared to surrounding undiseased tissue and compared the results with histology. We also imaged flow in four young mice (two AOM-treated and two control) showing no significant differences, which is expected so early after carcinogen exposure. We also present flow images of adenoma in a living mouse and a euthanized mouse to demonstrate that no flow is detected after euthanasia. Conclusion: We present, to the best of our knowledge, the first Doppler OCT images of in vivo mouse colon collected with a fiber-based endoscope. We also describe a fast and robust image processing method for segmenting vessels in the colon. These results suggest that Doppler OCT is a promising imaging modality for vascular imaging in the colon that requires no exogenous contrast agents. Lasers Surg. Med. 49:249–257, 2017.

Original languageEnglish (US)
Pages (from-to)249-257
Number of pages9
JournalLasers in Surgery and Medicine
Volume49
Issue number3
DOIs
StatePublished - Mar 1 2017

Fingerprint

Optical Coherence Tomography
Colon
Azoxymethane
Endoscopes
Adenoma
Blood Vessels
Colorectal Neoplasms
Mucous Membrane
Euthanasia
Second Primary Neoplasms
Tumor Biomarkers
Polyps
Microvessels
Carcinogens
Contrast Media
Histology
Lasers
Neoplasms

Keywords

  • adenoma
  • colorectal cancer
  • image processing
  • vascular imaging

ASJC Scopus subject areas

  • Surgery
  • Dermatology

Cite this

In vivo endoscopic Doppler optical coherence tomography imaging of the colon. / Welge, Weston A.; Barton, Jennifer K.

In: Lasers in Surgery and Medicine, Vol. 49, No. 3, 01.03.2017, p. 249-257.

Research output: Contribution to journalArticle

@article{053fde36be614ccbbe0f9c17473086a5,
title = "In vivo endoscopic Doppler optical coherence tomography imaging of the colon",
abstract = "Background and Objective: Colorectal cancer (CRC) remains the second deadliest cancer in the United States. Several screening methods exist; however, detection of small polyps remains a challenge. Optical coherence tomography (OCT) has been demonstrated to be capable of detecting lesions as small as 1 mm in the mouse colon, but detection is based on measuring a doubling of the mucosa thickness. The colon microvasculature may be an attractive biomarker of early tumor development because tumor vessels are characterized by irregular structure and dysfunction. Our goal was to develop an endoscopic method of detecting and segmenting colon vessels using Doppler OCT to enable future studies for improving early detection and development of novel chemopreventive agents. Method: We conducted in vivo colon imaging in an azoxymethane (AOM)-treated mouse model of colorectal cancer using a miniature endoscope and a swept-source OCT system at 1,040 nm with a 16 kHz sweep rate. We applied the Kasai autocorrelation algorithm to laterally oversampled OCT B-scans to resolve vascular flow in the mucosa and submucosa. Vessels were segmented by applying a series of image processing steps: (i) intensity thresholding; (ii) two-dimensional matched filtering; and (iii) histogram segmentation. Results: We observed differences in the vessels sizes and spatial distribution in a mature adenoma compared to surrounding undiseased tissue and compared the results with histology. We also imaged flow in four young mice (two AOM-treated and two control) showing no significant differences, which is expected so early after carcinogen exposure. We also present flow images of adenoma in a living mouse and a euthanized mouse to demonstrate that no flow is detected after euthanasia. Conclusion: We present, to the best of our knowledge, the first Doppler OCT images of in vivo mouse colon collected with a fiber-based endoscope. We also describe a fast and robust image processing method for segmenting vessels in the colon. These results suggest that Doppler OCT is a promising imaging modality for vascular imaging in the colon that requires no exogenous contrast agents. Lasers Surg. Med. 49:249–257, 2017.",
keywords = "adenoma, colorectal cancer, image processing, vascular imaging",
author = "Welge, {Weston A.} and Barton, {Jennifer K}",
year = "2017",
month = "3",
day = "1",
doi = "10.1002/lsm.22578",
language = "English (US)",
volume = "49",
pages = "249--257",
journal = "Lasers in Surgery and Medicine",
issn = "0196-8092",
publisher = "Wiley-Liss Inc.",
number = "3",

}

TY - JOUR

T1 - In vivo endoscopic Doppler optical coherence tomography imaging of the colon

AU - Welge, Weston A.

AU - Barton, Jennifer K

PY - 2017/3/1

Y1 - 2017/3/1

N2 - Background and Objective: Colorectal cancer (CRC) remains the second deadliest cancer in the United States. Several screening methods exist; however, detection of small polyps remains a challenge. Optical coherence tomography (OCT) has been demonstrated to be capable of detecting lesions as small as 1 mm in the mouse colon, but detection is based on measuring a doubling of the mucosa thickness. The colon microvasculature may be an attractive biomarker of early tumor development because tumor vessels are characterized by irregular structure and dysfunction. Our goal was to develop an endoscopic method of detecting and segmenting colon vessels using Doppler OCT to enable future studies for improving early detection and development of novel chemopreventive agents. Method: We conducted in vivo colon imaging in an azoxymethane (AOM)-treated mouse model of colorectal cancer using a miniature endoscope and a swept-source OCT system at 1,040 nm with a 16 kHz sweep rate. We applied the Kasai autocorrelation algorithm to laterally oversampled OCT B-scans to resolve vascular flow in the mucosa and submucosa. Vessels were segmented by applying a series of image processing steps: (i) intensity thresholding; (ii) two-dimensional matched filtering; and (iii) histogram segmentation. Results: We observed differences in the vessels sizes and spatial distribution in a mature adenoma compared to surrounding undiseased tissue and compared the results with histology. We also imaged flow in four young mice (two AOM-treated and two control) showing no significant differences, which is expected so early after carcinogen exposure. We also present flow images of adenoma in a living mouse and a euthanized mouse to demonstrate that no flow is detected after euthanasia. Conclusion: We present, to the best of our knowledge, the first Doppler OCT images of in vivo mouse colon collected with a fiber-based endoscope. We also describe a fast and robust image processing method for segmenting vessels in the colon. These results suggest that Doppler OCT is a promising imaging modality for vascular imaging in the colon that requires no exogenous contrast agents. Lasers Surg. Med. 49:249–257, 2017.

AB - Background and Objective: Colorectal cancer (CRC) remains the second deadliest cancer in the United States. Several screening methods exist; however, detection of small polyps remains a challenge. Optical coherence tomography (OCT) has been demonstrated to be capable of detecting lesions as small as 1 mm in the mouse colon, but detection is based on measuring a doubling of the mucosa thickness. The colon microvasculature may be an attractive biomarker of early tumor development because tumor vessels are characterized by irregular structure and dysfunction. Our goal was to develop an endoscopic method of detecting and segmenting colon vessels using Doppler OCT to enable future studies for improving early detection and development of novel chemopreventive agents. Method: We conducted in vivo colon imaging in an azoxymethane (AOM)-treated mouse model of colorectal cancer using a miniature endoscope and a swept-source OCT system at 1,040 nm with a 16 kHz sweep rate. We applied the Kasai autocorrelation algorithm to laterally oversampled OCT B-scans to resolve vascular flow in the mucosa and submucosa. Vessels were segmented by applying a series of image processing steps: (i) intensity thresholding; (ii) two-dimensional matched filtering; and (iii) histogram segmentation. Results: We observed differences in the vessels sizes and spatial distribution in a mature adenoma compared to surrounding undiseased tissue and compared the results with histology. We also imaged flow in four young mice (two AOM-treated and two control) showing no significant differences, which is expected so early after carcinogen exposure. We also present flow images of adenoma in a living mouse and a euthanized mouse to demonstrate that no flow is detected after euthanasia. Conclusion: We present, to the best of our knowledge, the first Doppler OCT images of in vivo mouse colon collected with a fiber-based endoscope. We also describe a fast and robust image processing method for segmenting vessels in the colon. These results suggest that Doppler OCT is a promising imaging modality for vascular imaging in the colon that requires no exogenous contrast agents. Lasers Surg. Med. 49:249–257, 2017.

KW - adenoma

KW - colorectal cancer

KW - image processing

KW - vascular imaging

UR - http://www.scopus.com/inward/record.url?scp=84983527744&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84983527744&partnerID=8YFLogxK

U2 - 10.1002/lsm.22578

DO - 10.1002/lsm.22578

M3 - Article

C2 - 27546786

AN - SCOPUS:84983527744

VL - 49

SP - 249

EP - 257

JO - Lasers in Surgery and Medicine

JF - Lasers in Surgery and Medicine

SN - 0196-8092

IS - 3

ER -