Establishing magnetic resonance imaging as an accurate and reliable tool to diagnose and monitor esophageal cancer in a rat model.
OBJECTIVE
To assess the reliability of magnetic resonance imaging (MRI) for detection of esophageal cancer in the Levrat model of end-to-side esophagojejunostomy.


BACKGROUND
The Levrat model has proven utility in terms of its ability to replicate Barrett's carcinogenesis by inducing gastroduodenoesophageal reflux (GDER). Due to lack of data on the utility of non-invasive methods for detection of esophageal cancer, treatment efficacy studies have been limited, as adenocarcinoma histology has only been validated post-mortem. It would therefore be of great value if the validity and reliability of MRI could be established in this setting.


METHODS
Chronic GDER reflux was induced in 19 male Sprague-Dawley rats using the modified Levrat model. At 40 weeks post-surgery, all animals underwent endoscopy, MRI scanning, and post-mortem histological analysis of the esophagus and anastomosis. With post-mortem histology serving as the gold standard, assessment of presence of esophageal cancer was made by five esophageal specialists and five radiologists on endoscopy and MRI, respectively.


RESULTS
The accuracy of MRI and endoscopic analysis to correctly identify cancer vs. no cancer was 85.3% and 50.5%, respectively. ROC curves demonstrated that MRI rating had an AUC of 0.966 (p<0.001) and endoscopy rating had an AUC of 0.534 (p = 0.804). The sensitivity and specificity of MRI for identifying cancer vs. no-cancer was 89.1% and 80% respectively, as compared to 45.5% and 57.5% for endoscopy. False positive rates of MRI and endoscopy were 20% and 42.5%, respectively.


CONCLUSIONS
MRI is a more reliable diagnostic method than endoscopy in the Levrat model. The non-invasiveness of the tool and its potential to volumetrically quantify the size and number of tumors likely makes it even more useful in evaluating novel agents and their efficacy in treatment studies of esophageal cancer.
Institute for the Treatment of Esophageal and Thoracic Disease, Allegheny Health Network, Pittsburgh, Pennsylvania, United States of America.
Juliann E
JE
Kosovec
Institute for the Treatment of Esophageal and Thoracic Disease, Allegheny Health Network, Pittsburgh, Pennsylvania, United States of America.
Ali H
AH
Zaidi
Institute for the Treatment of Esophageal and Thoracic Disease, Allegheny Health Network, Pittsburgh, Pennsylvania, United States of America.
Yoshihiro
Y
Komatsu
International Scholars Program, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
Pashtoon M
PM
Kasi
Department of Radiology, Allegheny Health Network, Pittsburgh, Pennsylvania, United States of America.
Kyle
K
Cothron
Department of Medicine, Allegheny Health Network, Pittsburgh, Pennsylvania, United States of America.
Diane V
DV
Thompson
Department of Pathology, Allegheny Health Network, Pittsburgh, Pennsylvania, United States of America.
Edward
E
Lynch
Institute for the Treatment of Esophageal and Thoracic Disease, Allegheny Health Network, Pittsburgh, Pennsylvania, United States of America.
Blair A
BA
Jobe
D000818:Animals; D019540:Area Under Curve; D004724:Endoscopy / Q000379:methods; D004938:Esophageal Neoplasms / Q000175:diagnosis* / Q000209:etiology; D005764:Gastroesophageal Reflux / Q000150:complications; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D008297:Male; D012372:ROC Curve; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results