In addition to DTI method, TA could assist in revealing the changes caused by infarction, also outside the lesion site. Damaged areas were found more heterogeneous and random in texture compared to unaffected sites.

Objectives: Airway dilator muscles play an important role in the analysis of breathingrelated symptoms, such as obstructive sleep apnoea. Texture analysis (TA) provides a new non-invasive method for analysing airway dilator muscles. In this study, we propose a TA methodology for airway dilator muscles and prove the robustness of this method. Methods: 15 orthognathic surgery patients underwent 3-T MRI. Computerized TA was performed on 20 regions of interest (ROIs) in the patients' airway dilator muscles. 53 texture parameters were calculated for all ROIs. The robustness of the TA method was analysed by altering the locations, sizes and shapes of the ROIs. Results: Our study shows that there is significant difference in TA results as the size or shape of ROI changes. The change of location of the ROI inside the studied muscle does not affect the TA results. Conclusions: The TA method is valid for airway dilator muscles. We propose a methodology in which the number of co-occurrence parameters is reduced by using mean values from four different directions (0°, 45°, 90°and 135°) with pixel spacing of 1 pixel. Dentomaxillofacial Radiology (2014Radiology ( ) 43, 20130403. doi: 10.1259 Cite this article as: Kölhi P, Järnstedt J, Sikiö M, Viik J, Dastidar P, Peltomäki T, et al. A texture analysis method for MR images of airway dilator muscles: a feasibility study. Dentomaxillofac Radiol 2014; 43: 20130403.

There is variation in the difference between the radiation dose reported by the CT scanner and actual measured dose.• This variation is substantial and may differ from zero.• To achieve more precise radiation dose data, especially in comparing studies, the average difference should be determined.• A correction factor for radiation dose should be utilized for every scanner used in studies.