The Study Of SPECT/CT Dynamic/Static Combined Imaging In Differential Diagnosis Of Orbital Tumors

Objectives The aim of the study was to assess the clinical value of ^99mTc-RBC SPECT/CT continuous dynamic/static imaging in the diagnosis,differential diagnosis and treatment strategy selection of orbital tumors,The SPECT imaging of OCH,vascular disease and other solid tumors was analyzed to determine the diagnostic criteria of different lesions.In order to find and solve the problems encountered in the preoperative qualitative diagnosis of orbital lesions,this technique can provide a theoretical and operational basis for better clinical application and further research.Methods 1)The results of ^99mTc-RBC SPECT imaging in 119 patients with orbital masses were retrospectively analyzed.Visual analysis:the distribution of radioactivity in bilateral orbital region and the time-radioactivity curve of perfusion phase in each phase.Semi-quantitative analysis:We measured the region of interest（ROI）in the delayed blood pool for about a week,and copied the ROI to the contralateral mirror region.The radioactivity T/N ratio of the tumor to the contralateral mirror region and the radioactivity T/S ratio of the tumor to the superior sagittal sinus region were calculated by two doctors,and the same doctor at different time.Bland-Altman analysis and paired T test were used to evaluate the repeatability and consistency of the two groups of data,in order to determine the feasibility of the technique.2)Retrospective analyzed the results of ^99mTc-RBC SPECT imaging of119 patients with orbital tumor,the T/N values of different pathological types were evaluated by semi-quantitative analysis and the statistical differences were detected.the diagnostic efficiency of ^99mTc-RBC SPECT imaging in the diagnosis of OCH were evaluated by visual analysis.The T/N values of ^99mTc-RBC SPECT imaging in vascular lesions and non-vascular lesions were determined and the statistical differences were detected.3)Retrospective analyzed the results of the diagnostic results of ^99mTc-RBC SPECT imaging,ultrasound and MRI in 140 patients with orbital masses.To analyze the diagnostic efficiency of different diagnostic techniques in different pathological types of orbital space-occupying lesions,and make a comparative analysis of them.Results 1)119 cases of orbital lesions were confirmed by postoperative pathology.Bland Altman analysis of T consistency in and between orbital lesions:the limits of95%consistency were-0.3023⁰.6894 dpm and-0.9112⁰.7821 dpm,respectively,with high consistency.The conformance of N and SSS measurement results in the normal orbital mirror area and SSS were consistent with Bland Altman analysis:-0.5040⁰.1814 dpm and-0.6348⁰.5703 dpm.the difference was not statistically significant.However,the consistency of intraorbital N and SSS measurements by doctor 1 at different time points with Bland Altman analysis of normal orbital mirror area and superior sagittal sinus were statistically significant,-1.089^-0.07268 dpm and-1.016^-0.01620 dpm,respectively.The reason may be that the radioactivity count of the healthy side is too low and the area of interest is easily disturbed by the normal tissue around it.There is no statistical difference in the overall repeatability between doctors.2)A total of 119 patients with orbital space-occupying lesions were included in this study,63 of whom were diagnosed correctly by ^99mTc-RBC SPECT continuous dynamic/static imaging.The diagnostic efficiency of ^99mTc-RBC SPECT imaging in diagnosis of OCH were 100.0%,98.2%,98.4%,100.0%and 99.2%.In addition,the diagnostic efficiency of ^99mTc-RBC SPECT in the diagnosis of orbital vascular tumors were 100.0%.But there is a lack of specificity in the identification of pathological types of orbital nonvascular tumors.Further diagnosis is made by SPECT/CT tomographic imaging for small lesions and deep location or inability to identify peripheral tissues.3)The diagnostic efficiency of ^99mTc-RBC SPECT combined continuous dynamic/static imaging,MR comprehensive analysis and Ultrasound scan in the diagnosis of OCH were as follows:100.0%,98.2%,98.4%,100.0%,9.2%;79.4%,100.0%,100.0%,83.7%,90.0%;88.2%,97.2%,96.8%,89.7%,92.9%,respectively.The results showed that SPECT imaging can diagnose OCH more accurately than MRI and Ultrasound.The specificity and positive predictive value of MRI were slightly higher than that of ultrasound scan,and there was no significant difference between the two methods.The results of Fisher showed that MRI and SPECT imaging were more accurate than Ultrasound scan in the diagnosis of OCH,and SPECT imaging was superior to MRI in diagnosis of OCH.In addition,the sensitivity,negative predictive value and accuracy of ultrasonography in the diagnosis of orbital vascular lesions were higher than those of MRI,and the difference was statistically significant.Although the specificity and positive predictive value of MRI were slightly higher than that of Ultrasound scan,there was no significant difference between the two methods.The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of MRI were slightly higher than those of ultrasound scan,but there was no significant difference between them.In a word,the sensitivity,specificity and accuracy of SPECT imaging in the diagnosis of vascular lesions,especially OCH,are still 100.0%.However,for the diagnosis of non-vascular lesions,the sensitivity,specificity and accuracy of^99mTc-RBC SPECT imaging alone were not as good as MRI and Ultrasound.Conclusion The ^99mTc-RBC SPECT imaging of OCH and venous hemangioma showed better reproducibility and less interference by surrounding tissues,which provided an important platform for accurate quantification of ^99mTc-RBC SPECT.SPECT has high specificity in the diagnosis of OCH by semi-quantitative analysis,and can guide the treatment decision more objectively.The diagnostic efficacy of SPECT was closely related to the pathological types of orbital lesions.The sensitivity and specificity of SPECT in the diagnosis of OCH and vascular diseases were higher.However,differential diagnosis of other tumors is less effective than conventional imaging techniques.SPECT can significantly improve the diagnostic level of orbital vascular lesions and provide a theoretical basis for the rational of preoperative diagnose.It is also a useful supplement to conventional imaging.