MRI findings of radiation-induced changes of masticatory muscles: a systematic review
1 Orthodontic Graduate Program, School of Dentistry, 476 Edmonton Clinic Health Academy (ECHA), University of Alberta, Edmonton, AB T6G 1C9, Canada
2 Department of Radiology and Diagnostic Imaging, Faculty of Medicine and Dentistry, University of Alberta, 2A2.41 WC Mackenzie Health Science Center, Edmonton, AB T6G 2R7, Canada
3 Canada Edmonton Clinic Health Academy (ECHA), Edmonton, AB, Canada
4 Division of Otolaryngology Head and Neck Surgery, Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta/Director of Clinics and International Relations, Institute of Reconstructive Sciences in Medicine, Misericordia Community Hospital, 16940-87 Avenue, Edmonton, AB T5R 4H5, Canada
5 Faculty of Medicine and Dentistry, 5-748, University of Alberta, Edmonton, AB T6G 1C9, Canada
Journal of Otolaryngology - Head and Neck Surgery 2013, 42:26 doi:10.1186/1916-0216-42-26Published: 28 March 2013
Radiotherapy to the head and neck regions can result in serious consequences to the temporomandibular joint (TMJ) and chewing muscles. Magnetic resonance imaging (MRI) demonstrates soft-tissue alterations after radiotherapy, such as morphology and signal intensity.
The purpose of this review is to critically and systematically analyse the available evidence regarding the masticatory muscles alterations, as demonstrated on MRI, after radiotherapy for head and neck cancer.
Electronic search of MEDLINE, EMBASE, EBM reviews and Scopus.
Reports of any study design investigating radiation-induced changes in masticatory muscles after radiotherapy in patients with head and neck cancer were included.
Results and synthesis methods
An electronic database search resulted in 162 papers. Sixteen papers were initially selected as potentially relevant studies; however, only four papers satisfied all inclusion criteria. The included papers focused on the MRI appearance of masticatory muscles following radiotherapy protocol. Two papers reported outcome based on retrospective clinical and imaging records, whereas the remaining two papers were case reports. Irradiated muscles frequently show diffuse increase in T2 signal and post-gadolinium enhancement post-irradiation. Also, muscle size changes were reported based on subjective comparison with the contralateral side. The quality of all included papers was considered poor with high risk of bias.
There is no evidence that MRI interpretations indicate specific radiation-induced changes in masticatory muscles. There is a clear need for a cohort study comparing patients with pre- and post-radiotherapy MRI.