The Diagnostic Value Of Imaging Techniques For Detecting Temporal Bone Cholesteatoma

Temporal bone cholesteatoma is a cystic lesion consisting of squamous epithelial cells debris in the temporal bone.The exact etiology is not clear,but its intrinsic tendency of the invasive compression,expansion and erosion of the surrounding structures by cholesteatoma may lead to hearing loss,peripheral facial paralysis,meningitis,brain abscess and other serious complications.Currently,the mainstay treatment is surgical resection of the lesion and reconstruction of auditory function.However,recurrence or residual cholesteatoma often requires secondary surgery.High resolution computer tomography?HRCT?is a common imaging diagnostic method to evaluate the location and bone destruction of temporal cholesteatoma.However,HRCT cannot reliably distinguish cholesteatoma from noncholesteatoma such as granulation tissue,showing lower accuracy for diagnosis of recurrent or residual cholesteatoma after mastoidectomy.In recent years,more and more attention has been paid to the diagnostic value of magnetic resonance imaging?MRI?for cholesteatoma.In particular,diffusion weighted magnetic resonance imaging?DWI-MRI?combined with conventional MRI sequence has shown a good diagnostic value in evaluating the nature of middle ear lesions.However,DWI-MRI is a qualitative diagnostic tool,mainly based on doctor's experience for subjective judgment.Recently,some scholars have attempted to introduce apparent diffusion coefficient?ADC?for quantitative diagnosis of cholesteatoma.The purpose of this study is to compare and evaluate the sensitivity and specificity of HRCT and MRI in the diagnosis of cholesteatoma,to explore the quantitative diagnostic value of MRI,and to determine an optimal cut-off value that can distinguish cholesteatoma from non-cholesteatoma,so as to provide help for the diagnosis of clinical cholesteatoma and to be used as a follow-up tool to reduce the possibility of non-essential secondary surgery.Objective1.To compare the accuracy of HRCT and MRI in the qualitative diagnosis of temporal bone cholesteatoma.2.To explore the quantitative diagnostic value of MRI in temporal bone cholesteatoma.3.To explore the optimal cut-off value for quantitative diagnosis of MRI and analyze the diagnostic value of HRCT,qualitative and quantitative diagnosis of MRI.Methods1.Participants and metheds:107 patients?125 ears?with clinically suspected cholesteatoma were analyzed from September 2017 to March 2019,including 67males and 40 females,aged from 3 to 79 years,with an average age of 40.14±18.8years.HRCT and MRI scans of temporal bone were routinely performed 3 days to 2weeks before operation.The results of imaging examination were independently assessed by a radiologist and otologist marked as suspicious cholesteatoma and noncholesteatoma.Different opinions were discussed and decided together.Intraoperative findings were recorded as cholesteatoma and noncholesteatomatous inflammatory tissues,which were confirmed by histopathology.Quantitative parameter of MRI were measured by ADC value of DWI-MRI sequence,which was independently completed by two physicians who were blind to the clinical data and operation conditions of patients.There was no significant difference between the two measurements by statistical analysis,and the average of the two measurements was taken as the final measurement.2.Observation indicators:To analyze the sensitivity,specificity,positive and negative predictive values of HRCT and MRI in the diagnosis of cholesteatoma;to compare the ADC values of cholesteatoma and noncholesteatoma;to explore the optimal cut-off value of ADC in the diagnosis of cholesteatoma by ROC curve,and to further analyze the diagnostic value of HRCT,MRI qualitative and quantitative methods in differential diagnosis of cholesteatoma and noncholesteatoma.Result1.Qualitative diagnosis of cholesteatoma by HRCT and MRI:The sensitivity,specificity,positive predictive value?PPV?,negative predictive value?NPV?of HRCT was 68.8%,39.6%,64.6%and 44.2%,respectively,while for MRI was 96.1%,91.7%,94.9%and 93.6%respectively.The accuracy of DWI-MRI in the diagnosis of recurrent cholesteatoma was significantly higher than HRCT?P=0.026?.2.Quantitative diagnosis of MRI:ADC value for cholesteatom was 931.01,lowest value was 373,highest value was 1830,standard deviation was 251.780,quartile distance was 367.0,Average ADC value of noncholesteatomatous inflammatory lesions was 1881.26,lowest value was 1437.0,highest value was2369.0,standard deviation was 236.790,quartile distance was 377.0.The difference between the two groups was statistically significant for P<0.001.No significant difference was found between ADC values in primary and recurrent cholesteatoma?P>0.05?.3.ROC curve:The optimal cut-off value of ADC was 1384.70×10^-6 mm²/s,the Youden index was 0.980,the corresponding sensitivity was 98%and the specificity was 100%.The areas under the ROC curve of HRCT?MRI qualitative and quantitative were 0.542,0.939 and 0.994,respectively.Conclusions1.The accuracy of DWI-MRI in the diagnosis of cholesteatoma is significantly higher than HRCT,especially in the diagnosis of recurrent cases.2.A quantitative evaluation of DWI-MRI sequence with ADC value can identify cholesteatoma from non-cholesteatoma,with the optimal cut-off value of1384.70×10^-6 mm²/s.3.The diagnostic advantage of quantitative MRI in temporal bone cholesteatoma is significantly higher than qualitative MRI and HRCT.