Imaging Study Of Parotid Gland Disease

PART 1 A PRELIMINARY STUDY OF CT TEXTURE ANALYSIS IN THE DIFFERENTIAL DIAGNOSIS OF COMMON PAROTID EPITHELIAL TUMORSObjective To explore the diagnostic efficacy of 3D texture analysis based on CT image in differentiating common benign and malignant epidermal tumors of the parotid gland.Methods CT enhanced images of 138 patients with common benign and malignant epidermal tumors of parotid gland confirmed by pathology were retrospectively analyzed.Texture features,like mean,Uniformity,Energy,Entropy,Correlation,Contrast,Sum Entropy,Difference Entropy,Skewness and Correlation,were extracted by gray-level Histogram and Gray Level Co-occurrence Matrix.Kolmogorov-Smirnov test or Levene test was used for evaluating the significance of the difference between the benign and malignant parotid tumors on quantitative texture features.Receiver operating characteristic(ROC)curve,based on gold standard of pathology,was draw with prediction frequency.The specificity and sensitivity of that were respectively discussed by the maximum Youden’s index.Results(1)The Difference in Sum Entropy,Entropy,Mean,Contrast,Difference Entropy and Energy between parotid adenolymphoma andepidermal malignancies was statistically significant,and The Sum Entropy,Entropy,Mean,Contrast,Difference Entropy and Energy in the parotid adenolymphoma group were higher than that in the epidermal malignancies group(P<0.05).(2)Mean,Uniformity,Energy,Entropy,Correlation,Contrast,Sum Entropy,Difference Entropy between parotid adenolymphoma and pleomorphic adenoma was statistically significant,and Mean,Energy,Entropy,Correlation,Contrast,Sum Entropy,Difference Entropy in the parotid adenolymphoma group were higher than that in the pleomorphic adenoma group,while Uniformity in the pleomorphic adenoma group was much higher than that in the adenolymphoma group(P<0.05).(3)Mean,Uniformity,Energy,Entropy,Correlation,Sum Entropy between parotid adenolymphoma and epidermal malignancies was statistically significant,and Mean,Energy,Entropy,Correlation,Sum Entropy in the epidermal malignancies group were higher than that in the pleomorphic adenoma group,while Uniformity in the pleomorphic adenoma group was much higher than that in the epidermal malignancies group(P<0.05).(4)The diagnosis efficiency of Mean in the group of parotid adenolymphoma and epidermal malignant tumor was the best,and the AUC was 0.781.The sensitivity was 73.8%,the specificity was 71.1%,and the optimum diagnostic performance was 80.88.(5)The diagnosis efficiency of Energy in the group of parotid adenolymphoma and pleomorphic adenoma was the best,and the AUC was 0.910.The sensitivity was 73.8%,the specificity was 96.1%,and the optimumdiagnostic performance was 42558500.(6)The diagnosis efficiency of Energy in the group of parotid epidermal malignancy and pleomorphic adenoma was the best,and the AUC was 0.742.The sensitivity was 55.6%,the specificity was 86.3%,and the optimum diagnostic performance was31563064.Conclusion Quantitative parameters of 3D texture analysis based on CT images: Sum Entropy,Entropy,Mean,Contrast,Difference Entropy and Energy can effectively distinguish between parotid adenolymphoma and epidermal malignancies.Mean,Uniformity,Energy,Entropy,Correlation,Contrast,Sum Entropy,Difference Entropy can effectively distinguish the pleomorphic adenoma from adenolymphoma of the parotid gland.Mean,Uniformity,Energy,Entropy,Correlation,Sum Entropy can effectively distinguish between parotid pleomorphic adenoma and epidermal malignancies.According to the combined analysis of AUC,sensitivity and specificity,Mean is the ideal texture parameter for distinguishing parotid adenolymphoma from epidermal malignancy.Energy is the ideal texture parameter for distinguishing parotid adenolymphoma from pleomorphic adenoma.Energy is also the ideal texture parameter for distinguishing parotid adenolymphoma from epidermal malignancy.PART 2 TUBERCULOSIS OF THE PAROTID LYMPH NODES: IMAGING FEATURES Objectives To characterize clinical,CT and MRI features of tuberculosis(TB)of the parotid nodes.Methods 25 patients with parotid lymph node tuberculosis were retrospectively analyzed by two experienced radiologists in consensus,including the clinical data such as patients’ age,gender,clinical symptoms,tuberculosis exposure history,clinical misdiagnosis rate and related auxiliary examination ultrasonic,chest radiograph,PPD(purified protein derivative)and CT images and/or MR,observing the location of the lesions,shape,size,number,reinforcement way,the changes of parotid fascia and skin,the distribution of swollen lymph nodes and other imaging findings.Results The youngers(age<50y)account for 72% patients.80%patients were asymptomatic,and with no history of TB exposure.The clinic and imaging misdiagnosed 64% and 60% patients as tumors respectively,A total of 43 lesions were identified.38(88.4%)lesions involved superficial lobe.14(56%)cases had multiple lesions.There were four types of changes of the parotid fascia: local thickening(40%,n=10);local rupture with Thickened adjacent skin(28%,n=7);focal bulge(20%,n=5);and no changes(12%,n=3).Cervical lymphadenopathy was seen in14 out of 25 cases(56%).The lesions were enhanced in four patterns on CT images: homogeneous enhancement(37.1%,n=13),irregular cystic enhancement(37.1%,n=13),thick-walled ring enhancement(14.2%,n=5)and garland-like enhancement(11.4%,n=4).On MRI,the signal of lesions was isointense on T1-weighted image(T1WI),hyperintense on T2-weighted image(T2WI),markedly hyperintense on diffusion-weighted imaging(DWI)and a low signal on the apparent diffused coefficient(ADC)map.Conclusions Tuberculosis of the parotid nodes tend to simulate tumors clinically and radiologically.Their preferential sites are the superficial lobe.The youngers with PPD skin test positive and lesions accompanying with cervical lymphadenopathy,changes of the parotid fascia and parotid parenchyma edema adjacent to the lesions on CT and MRI may be helpful in the diagnosis and facilitate the differential diagnosis.