The Application Of Optical Coherence Tomography Angiography In Microvessel Of Benign And Malignant Diseases

ObjectiveTo observe the real condition of microvessel and explore the relationship of pathological changes and microvessel changes with skin cancer by optical coherence tomography angiography?OCTA?.To compare the microvascular differences between the lesion area and the corresponding normal skin area by OCTA and achieve clinical non-invasive diagnosis of benign and malignant diseases,real-time monitoring of microvascular disease changes.Methods1?Improvement of image analysis and parameters of optical coherence tomography angiography equipment:The OCTA device was tested to select the appropriate parameters and obtain better vascular images.2?Build subcutaneous transplantation tumor model of human colon cancer in mice:20?l of CT26 rectal cancer cell suspension with a concentration of 2×10⁶/ml was injected into the ears Balb/c mice,and it was considered successful when the tumor diameter was reach 3-5 mm.3?A method for exploring mice model induced ear skin cancer:30?l of 100?g/100?l of 7,12-dimethylphenylhydrazine?DMBA?/Acetone solution on the first day and fourth day in the first week.Then,30?l of 4?g/100?l phorbol ester?TPA?/acetone solution was applied to the ears of the mouse every Monday and Thursday.The ears were imaged by OCTA at 0 days,7 days,21 days,35 days and 50 days.Next,the ears were embedded in paraffin,sliced and observed the pathological changes by HE staining.4?Enroll PWS patients:21 patients with PWS were enrolled in this study randomly at the Department of Laser of Chinese PLA Hospital.The patients who have light sensitive dermatoses,immune disorders or who during their pregnant and lactation period were excluded.All participants only received photodynamic therapy?PDT?less than two times.5?OCTA system scanning:The lesion area of PWS and corresponding normal skin area,the ear subcutaneous tumour area and the normal ear skin area of Balb/c mice were scanned by OCTA equipment.Microvascular imaging with induced ear skin cancer were scaned at different period,and repeated three times during every scanning.6?Image processing and analysis:the image was divided into three layers by SegmentV1₁ software;the vascular density was analyzed by Density_V1.4;the three-dimensional image of microvessels was constructed by Amira software.7?Statistical analysis:IBM SPSS Statistics 20 software was used to analyze blood vessel density in lesion area and corresponding normal skin area of PWS patients by paired sample T test.Results1?We can see the microvessel density of the ear subcutaneous tumors in Balb/c mice was higher than that of the normal ear skin.2?During the induction of ear skin cancer in Balb/c mice,the changes of ear skin redness and swelling were observed.The results of microvascular images collected by OCTA system corresponded well with the pathological results.On the 7th day,the ear skin was severely red and swollen,and the OCTA images were relatively limited.Pathological examination showed that the proliferation of epidermal cells,microvessels and inflammatory cells was obvious.3?OCTA showed clear blood vessel images.The microvascular distribution of PWS was more realistically.4?Compared with the corresponding normal area skin,the blood vessels in the lesion area were more tortuous,denser and larger in diameter.As we can see the vessel density from three layers dived by Density_V1.4 software and SegmentV1₁ software?first layer:t=3.794,p=0.001,df=20,95%CI=2.25-7.76;second layer:t=-5.514,p=0.000,df=20,95%CI=-9.93^-4.48;third layer:t=-3.666,p=0.002,df=20,95%CI=-4.55^-1.25?.Studies have shown that blood vessel density was greater at 0.21 to 0.35 mm below the skin surface.Gender and diseased areas had an impact on pathological features,however,this study did not analyze the differences of vascular pathology at different ages.ConclusionsThe OCTA system can be used for imaging and real-time monitoring of microvessels in benign and malignant diseases.By analyzing blood vessel morphology and parameters,it can reflect the pathological features of the vascular disease better,and provide a basis for realizing clinical non-invasive diagnosis,real-time monitoring and evaluation of microvascular disease treatment effects.