Multimodal imaging using optical coherence tomography and endolaryngeal ultrasonography in a new rabbit VX2 laryngeal cancer model.
OBJECTIVE
Optical coherence tomography (OCT) provides ultrahigh-resolution imaging of tissues within a depth of a few millimeters, whereas ultrasonography provides good imaging further below the surface. We aimed to develop a minimally invasive rabbit model of VX2 laryngeal cancer, suitable for these two imaging modalities through a transoral approach. We also sought to study the utility of combined OCT and endolaryngeal ultrasonography (EUS) for evaluation of early and advanced laryngeal cancer, using this model.


METHODS
VX2 tumor suspension was inoculated into the vocal folds of ten rabbits by injection through the trans-thyrohyoid membrane. The tumor model was characterized by rigid laryngoscopy and the tumor generation rate was 80% (8/10). Correlation between frequency-domain OCT and high-frequency EUS were used to visualize laryngeal tumors in the area of protruding mass formation in four rabbits, one week after injection (group A) and the remaining four rabbits two weeks after injection (group B).


RESULTS
A small submucosal tumor was observed with rigid laryngoscopy in group A, and pathologic evaluation showed that the tumor was close to the basement membrane of the vocal fold mucosa, but had not invaded. OCT confirmed that the lining of the mucosa and basement membrane of the vocal fold was not broken, but the mucosa had thinned at the most elevated ridge. However, these lesions were not detected by EUS, and the overall shape of the tumor could not be clearly identified by EUS. A large tumor filling the laryngeal lumen was observed with rigid laryngoscopy in group B, and nearly the entire vocal fold, including the paraglottic space, was found to be involved on pathologic analysis. Distinguishing between normal structures and tumor was difficult using OCT; however, EUS confirmed the overall shape, size, and extent of the tumor, and the paraglottic space and thyroid cartilage were shown to be intact.


CONCLUSIONS
This study is the first experimental trial, assessing the value of multimodal imaging using OCT and EUS in a rabbit VX2 laryngeal tumor model. Combining OCT and EUS helped to identify changes in laryngeal mucous membranes, and could potentially be used to identify laryngeal tumors and predict how tumors progress. This combined modality could help in determining tumor extent, assisting in diagnosis, and establishing a treatment plan for laryngeal cancer.
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Internal Medicine, Kosin University College of Medicine, 34 Amnam-dong, Seo-Gu, Busan, 602-030, South Korea.
Chulho
C
Oak
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Biomedical Engineering and Center for Marine-Integrated Biomedical Technology, Pukyong National University, 45 Yongso-ro, Nam-gu, Busan, 608-737, South Korea.
Yeh-Chan
YC
Ahn
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Internal Medicine, Kosin University College of Medicine, 34 Amnam-dong, Seo-Gu, Busan, 602-030, South Korea.
Sung-Jin
SJ
Nam
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Internal Medicine, Kosin University College of Medicine, 34 Amnam-dong, Seo-Gu, Busan, 602-030, South Korea.
Maan Hong
MH
Jung
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Biomedical Engineering and Center for Marine-Integrated Biomedical Technology, Pukyong National University, 45 Yongso-ro, Nam-gu, Busan, 608-737, South Korea.
Sang Seok
SS
Hwang
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Biomedical Engineering and Center for Marine-Integrated Biomedical Technology, Pukyong National University, 45 Yongso-ro, Nam-gu, Busan, 608-737, South Korea.
Yu-Gyeong
YG
Chae
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Otolaryngology-Head and Neck Surgery, Kosin University College of Medicine, 34 Amnam-dong, Seo-Gu, Busan, 602-030, South Korea.
Hyoung Shin
HS
Lee
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Otolaryngology-Head and Neck Surgery, Kosin University College of Medicine, 34 Amnam-dong, Seo-Gu, Busan, 602-030, South Korea.
Kang Dae
KD
Lee
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Pathology, Kosin University College of Medicine, 34 Amnam-dong, Seo-Gu, Busan, 602-030, South Korea.
Min Jung
MJ
Jung
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Pathology, Kosin University College of Medicine, 34 Amnam-dong, Seo-Gu, Busan, 602-030, South Korea.
Bong Kwon
BK
Chun
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Thoracic and Cardiovascular Surgery, Kosin University College of Medicine, 34 Amnam-dong, Seo-Gu, Busan, 602-030, South Korea.
Hae Young
HY
Lee
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Medical Humanities and Social Medicine, Kosin University College of Medicine, 34 Amnam-dong, Seo-Gu, Busan, 602-030, South Korea.
Eun-Kee
EK
Park
Innovative Biomedical Technology Research Center, Busan, 602-030, South Korea.|Department of Otolaryngology-Head and Neck Surgery, Kosin University College of Medicine, 34 Amnam-dong, Seo-Gu, Busan, 602-030, South Korea.
Sung Won
SW
Kim
D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis*; D004195:Disease Models, Animal; D019160:Endosonography; D007822:Laryngeal Neoplasms / Q000175:diagnosis*; D008297:Male; D064847:Multimodal Imaging; D011817:Rabbits; D041623:Tomography, Optical Coherence
endolaryngeal ultrasonography; laryngeal cancer; optical coherence tomography; vocal fold