Radiotherapy Induced Changes of Masticatory Muscles and Parotid Glands On Mri In Patients With Nasopharyngeal Carcinoma

Authors : Taner Arpaci, Gamze Uğurluer, Gülhan Örekici, Tuğana Akbaş, Meltem Serin

Pages : 621-626

View : 60 | Download : 27

Publication Date : 2019-12-01

Article Type : Research

Abstract :Objective: The aim of this study was to identify radiotherapy RT induced changes of masticatory muscles and parotid glands on magnetic resonance imaging MRI in patients with nasopharyngeal carcinoma NPC .Patients and Methods: Thirty-one patients treated with RT for NPC between 2009-2016 in our instution were included in the study. MRI examinations performed before and after RT were reviewed retrospectively. Transverse diameters and signal intensities of masticatory muscles and parotid glands were evaluated on T2 weighted axial MR images. Normal hypointense signal was scored as 0, mild hyperintensity as 1 and severe hyperintensity as 2. Results:The mean interval between pre-RT MRI and last control MRI was 44 months 12-84 months . Reductions of transverse diameters were; right masseter RM :2.32mm 15% , left masseter LM :2.42mm 15.4% , right medial pterygoid RMP :1.26mm 8.7% , left medial pterygoid LMP :1.71mm 12% , right lateral pterygoid RLP :1.35mm 9.6% , left lateral pterygoid LLP :1.32mm 9.4% , right parotid gland RP :8.22mm 26% , left parotid gland LP :8.87mm 28% . T2 signal changes were; RM: mild 8 cases 26% , LM: mild 5 cases 16% , RMP: mild 5 cases 16% , severe 1 case 3.5% , LMP: mild 4 cases 13% , severe 2 cases 6.5% , RLP and LLP: mild 8 cases 26% , severe 3 cases 9.7% , RP: mild 10 cases 32% , severe 18 cases 58% , LP: mild 10 cases 32% , severe 17 cases 55% . Conclusion: Volume loss and hyperintensity were mostly seen in parotid glands. Masseter was the muscle with highest rate of volume loss and lateral pyterygoid showed the highest rate of hyperintensity in masticatory muscles
Keywords : Magnetic resonance imaging, masticatory muscle, nasopharyngeal carcinoma, parotid gland, radiotherapy