Hidetake Yabuuchi MD, Presenter: Nothing to Disclose

Masamitsu Hatakenaka MD, PhD, Abstract Co-Author: Nothing to Disclose

Yoshio Matsuo, Abstract Co-Author: Nothing to Disclose

Shunya Sunami MD, Abstract Co-Author: Nothing to Disclose

Takeshi Kamitani MD, Abstract Co-Author: Nothing to Disclose

Hiroshi Honda MD, Abstract Co-Author: Nothing to Disclose

Mikako Jinnouchi MD, Abstract Co-Author: Nothing to Disclose

Masato Yonezawa, Abstract Co-Author: Nothing to Disclose

To find the strongest parameter to characterize anterior mediastinal solid tumors using combination of dynamic contrast-enhanced MRI, diffusion-weighted MRI, and FDG-PET/CT

33 lesions in 33 patients (16 male and 17 female, age range 15-72 years old, mean 52.2) of histilogically confirmed anterior mediastinal solid tumors with surgical specimen were enrolled. Institutional review board was obtained, and informed consent was waived. Dynamic contrast-enhanced MRI (DCE-MRI), diffusion-weighted MRI (DWI), and FDG-PET were performed in all patients within two weeks before surgery. DCE-MRI was obtained before and every 30 seconds of 5 minutes after contrast enhancement. The time to peak enhancement, maximum enhancement ratio, and washout ratio were determined from time-signal intensity curves of DCE-MRI. The apparent diffusion coefficient (ADC) of each mediastinal tumor was calculated from DWI. Analyzed imaging parameters were the presence of capsule/septation on T2-weighted MR images, time-signal intensity curve pattern, maximum enhancement ratio, washout ratio on DCE-MRI, ADC derived from DWI, and SUVmax on FDG-PET/CT. Fisher’s exact test or chi-square test was used to determine the association between parameters and histologic types of anterior mediastinal solid tumors. P < .05 was considered to be statistically significant

This study included 18 thymomas, 5 malignant lymphomas, 4 hemangiomas, 3 non-seminomatous malignant germ cell tumors, and 3 thymic carcinomas. Washout pattern on DCE-MRI was only seen in thymoma (12/18) and thymic carcinoma (1/3). SUV max of lymphoma (mean, 18.3), non-seminomatous germ cell tumors (14.2) and thymic carcinomas (20.7) was significantly higher than that of thymoma (6.2). There was no significant difference in ADC and other parameters between histologic types.

SUV max on FDG-PET and time-intensity curve pattern on DCE-MRI might be useful to differentiate anterior mediastinal solid tumors, whereas ADC was not a significant discriminator.

Preoperative discrimination between lymphoma and other anterior mediastinal solid tumors using FDG-PET and DCE-MRI might be useful because thoracotomy could be avoided for lymphomas.

Yabuuchi, H, Hatakenaka, M, Matsuo, Y, Sunami, S, Kamitani, T, Honda, H, Jinnouchi, M, Yonezawa, M, Anterior Mediastinal Solid Tumors: Characterization Using Dynamic Contrast-enhanced MRI, Diffusion-weighted MRI and FDG-PET/CT.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11010121.html