The Application Study Of DSC PWI And DWI In BT-RADS 3 Category Lesions Of High-grade Glioma Patients

Background:Glioma is the most common tumor of all primary central nervous system tumors,of which high-grade gliomas(HGG)account for about 3/4.Nowadays,the standard treatment protocol is total or subtotal resection,followed by concomitant radio-chemotherapy(CCRT)and adjuvant chemotherapy with temozolomide(TMZ).Treatment-related changes,such as pseudoprogression and radiation necrosis,often confuse clinicians and radiologists due to its similar characteristics with tumor progression on conventional magnetic resonance imaging(MRI).Timely and accurate differentiation of tumor recurrence from non-recurrence during follow-up is critical in order to choose the appropriate treatment approach and improve prognosis.Brain Tumor Reporting and Data System(BT-RADS)is a simplified classification system to evaluate the effectiveness of post-treatment brain tumors,lesions with imaging data that suggest growth or progression are defined as BT-RADS Category 3,these lesions are further subdivided into 3 subtypes including Category 3a,3b and 3c according to the different possibility of tumor recurrence.However,the ability of BT-RADS to differentiate category 3 lesions into tumor recurrence versus non-recurrence has yet to be demonstrated.Dynamic susceptibility contrast-enhanced perfusion-weighted imaging(DSC PWI)and diffusion-weighted imaging(DWI)can reflect physiological and pathological information such as angiogenesis and movement of water molecules,and studies have shown they may be valuable for differentiating tumor recurrence from treatment-related changes.Purpose:To investigate the application of BT-RADS in response assessment of post-treatment HGG.Furthermore,the added value of DSC PWI and DWI to BT-RADS for differentiating tumor recurrence from non-recurrence in patients with category 3 lesions was further discussed.Materials and methods:This prospective study was approved by the Institutional Review Board of Guangdong Provincial People's Hospital,Guangdong Academy of Medical Sciences.The clinical and imaging data in patients with pathological diagnosis of HGG in our hospital from January 2015 to December 2018 were analyzed,the BT-RADS category of all cases was independently assessed online(http://btrads.com/publications/)in the light of conventional MR imaging data by two experienced neuroradiologist,these included lesions were divided into tumor recurrence group and non-recurrence group by secondary surgery or clinical follow-up observation.The maximal relative cerebral blood volume(rCBVmax),mean relative cerebral blood volume(rCBVmean),mean apparent diffusion coefficient(ADCmean)and minimum apparent diffusion coefficient(ADCmin)were measured in the maximum anomaly level.The difference in age,sex,enhancing lesion diameter,Karnofsky performance status(KPS)score,primary surgery,World Health Organization(WHO)grade,isocitrate dehydrogenase(IDH)genotype,time interval from CCRT to identification of BT-RADS category 3 in tumor recurrence group and non-recurrence group were compared by using two independent sample t test or chi-square test,the difference of BT-RADS category,rCBVmax,rCBVmean,ADCmean,ADCmin in tumor recurrence group and non-recurrence group were compared by using contingency tables or Mann-Whitney U-test.Receiver operating characteristic(ROC)curve analysis was performed to determine the diagnostic performance of different parameter combinations for discriminating tumor recurrence from non-recurrence,meanwhile,their area under the curve(AUC)were calculated.The accuracy,sensitivity,specificity,positive predictive value(PPV),and negative predictive value(NPV)based on optimum cutoffs were compared.Results:A total of 91 patients with BT-RADS Category 3 lesions were included in the first diagnosis,28 patients were Category 3a,26 Category 3b,and 37 Category 3c.Of the 91 patients,51 had tumor recurrences,and 40 did not have a recurrence.There were statistical significance in KPS score,primary surgery and time interval from CCRT to identification of BT-RADS category 3 in tumor recurrence group and non-recurrence group.The rCBVmax(2.34 vs 1.34)and rCBVmean(1.89 vs 1.13)of the tumor recurrence group were significantly higher than those of the non-recurrence tumor group(both p<0.001).The ADCmean(0.81×10-3mm2/s vs 1.27×10-3mm2/s)of the tumor recurrence group was significantly lower than that of the non-recurrence group(p<0.001),the ADCmin(0.78×10-3mm2/s vs 0.84×10-3mm2/s)in the tumor recurrence group was lower than that in the non-recurrence group,although the difference was not statistically significant(p=0.052).The AUC values of BT-RADS,BT-RADS+rCBVmax,BT-RADS+rCBVmean,BT-RADS+ADCmean,BT-RADS+rCBVmax/+ADCmean,BT-RADS+rCBVmean+ADCmean in differentiating between tumor recurrence and non-recurrence were 0.756,0.896,0.863,0.875,0.947 and 0.926,respectively.The combination of BT-RADS,rCBVmax,and ADCmean exhibited the best accuracy(92%),with sensitivity of 98%and specificity of 85%.Conclusion:BT-RADS classification system has moderate predictive performance for tumor recurrence in patients with postoperative HGG,adding rCBVmax and ADCmean to BT-RADS can significantly improve the diagnostic performance for differentiating tumor recurrence from non-recurrence in BT-RADS category 3 lesions.