The Predictive Value Of The Infrared Thermal Imaging In Prediction Of Postherpetic Neuralgia

Objective:The purpose of this trial was to explore the predictive value of the infrared thermal imaging in prediction of postherpetic neuralgia in patients with acute herpes zoseter?HZ?by observing the infrared thermography characteristics of HZ and postherpetic neuralgia?PHN?and its influence factors.And hope to find a objective and noninvasive prediction method for PHN,to achieve early prevention and treatment.Methods:Patients with HZ and PHN admitted to the Department of Dermatology or Department of Pain of the Affiliated Hospital of Southwest Medical University from November 2017 to December 2018 were selected in this study,and were divided into HZ group and PHN group according to diagnosis.Gender,age,height,weight,combined disease,course of disease,VAS were recorded of all patients,and infrared thermal imaging was carried,and the temperature difference of the herpes area and the symmetrical area??T?and the area of temperature changed?ATC?were measured.In HZ group the prodromal pain,area of pain and disease score also recored.To observe the infrared thermography characteristics of patients with HZ who was before treatment and PHN and its influence factors.The patients in HZ group received antiviral,nutritional nerve and analgesic treatment for 7 to14 days.After treatment,the VAS,disease score,?T and ATC were recorded again.The patients in HZ group have completed infrared thermal imaging before and after treatment were recruited in HZ₁ group,to observe the infrared thermography characteristics of HZ after treatment.The patients in HZ₁ group were divided into PHN₁ group and non-PHN₁ group according to whether the lesion area is sustain pain after 1 month of discharge.The observation indicators differences between the two group were analyzed,and the receiver operator characteristic curve was made and the area under the curve was calculated to comparative prediction performance between the infrared thermal imaging with the current methods for predicting PHN,to explore the predictive value of the infrared thermal imaging in prediction of PHN in patients with acute HZ.Results:146 cases with HZ were included in HZ group,60 cases with PHN were included in PHN group,and 74 cases in HZ group were included in HZ₁ group.1.The infrared thermography characteristics of acute HZ:?1?In HZ group,the infrared thermography in the lesion area before treatment showed 64.39%?94 cases?was high temperature,30.82%?45 cases?was no significant changed and 4.79%?7 cases?was low temperature.?2?The multiple linear regression analysis of the infrared imaging results in HZ group showed:the?T pre-treatment was positively correlated with the disease score?B=0.160,P<0.001?,and negatively correlated with the course of disease?B=-0.029,P=0.01?.The ATC pre-treatment was positively correlated with the area of pain?B=0.072,P=0.033?.The?T pre-treatment was positively correlated with the ATC?r=0.301,P<0.001?.?3?In HZ₁ group,the infrared thermography in the lesion area showed 75.68%?56 cases?the changed temperature return to normal,but 24.32%?18 cases?remained high temperature.2.The infrared thermography characteristics of PHN:?1?The infrared thermography in the lesion area in PHN group showed:the course of disease was 1 month was mainly high temperature,12 cases?66.6%?of 18 cases was high temperature,and the course of disease was 2³ months,9 cases?42.86%?of 21 cases was high temperature and 10 cases?47.62%?of 21 cases was low temperature,and the course of disease?4 months,12 cases?57.14%?of 21 cases was low temperature.?2?The multiple linear regression analysis of the infrared imaging results in PHN group showed:the infrared imaging results were no significant correlated with clinical indicators.3.The predictive value of the infrared thermal imaging in prediction of PHN in patients with acute HZ:?1?In HZ₁ group,17 cases developed into PHN,57 was non-PHN,the incidence of PHN was 22.97%.?2?The difference between PHN₁ guroup and non-PHN₁group:there were no statistical significant in age,gender,height,weight,prodromalpain,herpesposition,?Tpre-treatmentandATC pre-treatment?P>0.05?,but the course of disease?t=2.217,P=0.002?,rate of combined diseases?x²=5.288,P=0.021?,area of pain?t=3.217,P=0.002?,VAS before and after treatment?t=3.083,P=0.003;t=2.819,P=0.006?,condition score before and after treatment?t=3.240,P=0.002;t=2.512,P=0.021?,?T after treatment?t=3.009,P=0.004?,ATC after treatment?t=4.796,P<0.001?in PHN₁group were significantly higher than non-PHN₁ group,and the?T remission rate?t=-5.588,P<0.001?,ATC remission rate?t=-5.263,P<0.001?in PHN₁group were significantly lower than non-PHN₁ group.?3?The ROC curve results showed that:In the HZ₁ group,the AUC in the infrared imaging results greater than the VAS,disease score,course of disease and area of pain.In the curve of?T after treatment,the AUC was 0.807,and in the curve of ATC after treatment,the AUC was 0.807,and in the curve of?T remission rate,the AUC was 0.848,and in the curve of ATC remission rate,the AUC was 0.861,and in the curve of course of disease,the AUC was 0.672,and in the curve of VAS before treatment,the AUC was 0.718,and in the curve of area of pain,the AUC was 0.732,and in the curve of condition score before treatment,the AUC was0.739,and in the curve of VAS after treatment,the AUC was 0.690,and in the curve of condition score after treatment,the AUC was 0.696.The cut-off of the?T after treatment for predicting PHN was 0.73?.Conclusion:1.The infrared thermography in the lesion area showed:HZ in acute pre-treatment mainly was high temperature,and the degree of temperature changed was positively correlated with the disease score and negatively correlated with the course of disease,and after treatment most return to normal.In the early stage of PHN mainly was high temperature,but mainly was low temperature with the disease course extended.2.The temperature difference of the herpes area and the symmetrical area in infrared thermography of patients with HZ after treatment greater than 0.73°C has a predictive effect on PHN.