Use Of Texture Analysis On Mri To Differentiatebetween Advanced Stages Of Nasopharyngeal Carcinoma And Topredict The Treatment Response In Nasopharyngeal Carcinoma

Background:Nasopharyngeal carcinoma is a common malignant tumour in Asian countries of which nearly 80%of them are squamous cell carcinoma.The standard treatment for the patients with nasopharygeal carcinoma is radiotherapy.The survival rates have improved with the combination of chemotherapy with radiotherapy.Patients with advanced nasopharygeal carcinoma(stage Ⅲ-IVB)generally have poorer prognosis owing to failure of treatment.The main factors for treatment failure are local recurrence and distant metastasis.The pretreatment prediction of response to treatment will help to change the course and aggressiveness of the treatment.MRI is frequently used in the diagnosis and follow-up oftumours.It gives better contrast of the tissues and produce less artefacts compared to computer tomography/CT.The heterogeneity of a tumour plays a crucial role to the clinical diagnosis,staging and prognosis of nasopharygeal carcinoma.Texture analysis is a latest technique used also in MRI to extract parameters and thus quantifying intra-tumoural heterogeneity.Objective:(1)To investigate the potential of MRI(T2W&CE T1W)texture analysis in differentiating stage Ⅲ from stage Ⅳ nasopharyngeal carcinoma.(2)To investigate the potential of MRI(T2W&CE T1W)texture analysisto predict the degree of treatment response in patients with Nasopharyngeal carcinoma(squamous cell carcinoma).Materials&methods:Study:Retrospective study at the Department of Radiology and Nuclear MedicineStudy area:The First Affiliated Hospital of Dalian Medical University.Study population:One hundred eight cases of nasopharyngeal carcinoma were collected from the database of the first affiliated hospital of Dalian medical university from 2011-02 to 2017-07.53 cases were selected from this list to study the potential of MRI to predict the treatment response and 55 cases were excluded according to the criteria.Patients with histologically proven squamous cell carcinoma of the nasopharynx was grouped into two:Residual/no or partial responders(N=27)&Non-Residual/Complete Responders(n=26)based on the post-treatment follow up magnetic resonance images after 6 months of treatment.Stage Ⅰ=5 cases(3 in non-residual group and 2 cases in residual group),stageⅡ = 8 cases(2 cases in non-residual and 6 cases in residual group),stage Ⅲ = 24 cases(17 cases in non-residual group and 7 cases in residual group)and stage Ⅳ = 16 cases(4 cases in non-residual group and 12 cases in residual group)Source of data:The First Affiliated Hospital of Dalian Medical University’s database.Image Collection&Procession:MRI scans were performed with 3 Tesla GE SIGNA HDxt(Healthcare,USA)machine.The MRI including axial CET1 and axial T2WI of 53 nasopharyngeal carcinoma cases were collected.For each lesion,the Region Of Interest/ROI was contoured around the largest cross-sectional area of the lesion.The texture analysis was performed with Omni-Kinetics Software.Data Collection&Procession:Texture parameters namely:a)First order histogram parameters(FOHP),b)Gray-level co-occurrence matrix(GLCM)parameters&c)Gray level run length maxia(GLRLM)parameters were listed and recorded from the Omni-Kinetics software.Statistical analysis:First and second order texture parameters were selected for statistical analysis on SPSS.24 software;Independent T-test and Mann-Whitney test were used to compare between the two groups-Stage III and Stage IV and Residual vs Non-residual;p<0.05 symbolizedstatistical significance.Receiver operating characteristics(ROC)were used to assess sensitivity and specificity.Results:(1)Cluster prominence in T2W images showed significance difference between stage Ⅲ and stage IV parameterswith p=0.007.Patients in Stage IV have poorer outcome compared to stage Ⅲ and so more patients in the residual group.Mean value ± Standard deviation of cluster prominence of stage Ⅳ group is higher than the stage Ⅲ group.Cluster prominence of Stage Ⅲ 4.85 ×102 ± 3.00 ×102,Cluster prominence of stage Ⅳ 7.67 × 102 ± 3.77 ×102.(2)Cluster prominence and Haralick correlation in T2W images between residual and non-residual parameters were significant-Cluster Prominence with p value of 0.004&Haralick Correlation with p value of 0.049.Cluster prominence:Mean value ± standard deviation of residual group is higher than the non-residual group.8.13 × 102± 3.98 × 102 for residual group and 4.95 x 102± 2.64 x 102 for non-residual group.Haralick correlation:Mean value ± standard deviation of residual group is higher than the non-residual group.12.80 × 103± 4.62 × 103 for residual group and 10.49 × 103± 6.O0× 103 for non-residual group.Conclusion:(1)Magnetic Resonance texture analysis of T2W images is a potential tool to differentiate stage III from stage IV nasopharyngeal carcinoma with one parameter-Cluster prominence showing significant difference.CE T1 images did not show significant difference between the 2 groups.Future studies in this field would be able to form a model which can be useful while treating advanced nasopharygeal carcinoma.(2)Texture analysis of T2W images showed potential to predict the response to treatment in patients with nasopharyngeal carcinoma.CE T1 images did not show significant difference between the residual and non－residual groups.There is a scope for studies in this topic to develop texture analysis as a reliable tool in predicting the response of treatment in patients with nasopharyngeal carcinoma.