Magnetic resonance imaging of swallowing-related structures in nasopharyngeal carcinoma patients receiving IMRT: Longitudinal dose-response characterization of quantitative signal kinetics

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• 作者：Jay A. Messer^a ; ^e ; ^{Jay.A.Messer@uth.tmc.edu" class="auth_mail" title="E-mail the corresponding author} ; Abdallah S.R. Mohamed^a ; ^f ; ^{asmohamed@mdanderson.org" class="auth_mail" title="E-mail the corresponding author} ; Katherine A. Hutcheson^b ; Yao Ding^a ; ^c ; Jan S. Lewin^b ; Jihong Wang^a ; Stephen Y. Lai^b ; Steven J. Frank^a ; Adam S. Garden^a ; Vlad Sandulache^b ; Hillary Eichelberger^a ; ^e ; Chloe C. French^a ; ^e ; Rivka R. Colen^d ; Jack Phan^a ; Jayashree Kalpathy-Cramer^g ; John D. Hazle^c ; David I. Rosenthal^a ; G. Brandon Gunn^a ; Clifton D. Fuller^a ; ^{cdfuller@mdanderson.org" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Nasopharyngeal carcinoma ; Magnetic resonance imaging ; Dysphagia ; Dose&ndash ; response ; Superior pharyngeal constrictor ; IMRT
• 刊名：Radiotherapy and Oncology
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：118
• 期：2
• 页码：315-322
• 全文大小：1110 K

文摘

We aim to characterize serial (i.e., acute and late) MRI signal intensity (SI) changes in dysphagia-associated structures as a function of radiotherapy (RT) in nasopharyngeal cancer (NPC) patients.

Materials and methods

We retrospectively extracted data on 72 patients with stage III-IV NPC treated with intensity-modulated RT (IMRT). The mean T1- and T2-weighted MRI SIs were recorded for the superior pharyngeal constrictor (SPC) and soft palate (SP) at baseline, early-after IMRT, and last follow up, with normalization to structures receiving <5 Gy.

Results

All structures had a significant increase in T2 SIs early after treatment, irrespective of the mean dose given. At last follow-up, the increase in T2 SI subsided completely for SPC and partially for SP. The T1 SI did not change significantly in early follow-up images of both structures; on late follow-up, patients with mean doses >62.25 Gy had a significant decrease in the corresponding T1 SI for SPC (1.6 ± 0.4 vs. 1.3 ± 0.4, P = 0.007) but decreased non-significantly for SP.

Conclusions

Serial MRI acquisitions enable the identification of both early and late radiation-induced changes in swallowing structures after definitive IMRT for NPC. Dose dependent decrease in late T1 SI is associated with higher RT doses to the superior pharyngeal constrictor muscle; while dose independent increase in SI for both structures in early post-RT T2 images is observed and subsides after therapy. Further efforts will seek to elucidate the relationship between dose-dependent muscle SI changes and functional alteration of swallowing muscles.