| The rapid development of optical coherence tomograph(OCT)imaging technology visualizes important structural and pathological changes of the retina,provides accurate evidence for early diagnosis,clinical treatment and prognosis of various lesions in macular or near macular.Due to its non-contact and high-resolution characteristics,it has become a very effective and adaptable imaging technology,which has great application prospects in both living body detection and biological tissue imaging.However,for retinal OCT images,the lesion intensity distribution is extremely uneven,usually showes low contrast and severe speckle noise.In clinical work,related lesions that recognize retinal tissue characteristics,such as choroidal neovascularization(CNV),are usually manually segmented by an ophthalmologist,which is subjective and takes a lot of time,so,a model suitable for retinal OCT image lesion segmentation is established.It is particularly important to evaluate the therapeutic effects of lesions such as CNV.CNV refers to the process of abnormal vascular growth from the choroid layer to the retina.This symptom may lead to sudden deterioration of central vision,allergies,and even more severe new blood vessel bleeding.The formation of CNV is a group of pathological termination of chorioretinal diseases,such as wet age-related macular degeneration(wAMD),pathological myopia(PM),etc..Pathological myopia(PM)is a group of common eye diseases with progressive diopter deepening,increasing axial length,often accompanied by progressive damage of retinal choroidal tissue,and poor visual acuity.In the pathological myopia of retinal choroidal damage,pathological myopia choroidal neovascularization(mCNV)is an important cause of visual loss and even loss of vision in patients.The high incidence of choroidal neovascularization caused by pathological myopia in China and the severity of visual impairment in the center make mCNV become one of the main causes of blindness in young and middle-aged people over 30 years old.Age-related macular degeneration(AMD)is a chronic progressive disease of the central retina.AMD is mainly divided into two categories:dry and wet.Dry AMD often shows progressive decline in binocular vision,visible macular degeneration,choroidal capillary atrophy and formation of drusen.Most of the wet AMD is a first-onset disease.The main feature is the formation of choroidal neovascularization(CNV),which causes the loss of vision in patients with wet age-related macular degeneration.It can cause blood and tissue fluid to exudate,causing the retinal destruction,abnormal function,resulting in blind spots in the central field of vision,causing blindness in patients.Vascular endothelial growth factor(VEGF)has been shown to be closely related to the production of CNV.It is a multifunctional cytokine that acts on vascular endothelial cells and is the most powerful angiogenesis promoter found in the current study factor.By binding to specific receptors on vascular endothelial cells,it exerts a strong differentiation-promoting and chemotaxis effect on vascular endothelial cells,promotes proliferation and migration of endothelial cells,and stimulates angiogenesis.In addition,VEGF can increase vascular permeability,allowing macromolecular substances in the blood to enter the extracellular matrix,forming fibrin gel,etc.,to FFAcilitate the growth of new blood vessels and stromal cells.VEGF also increases the production of tissue factors and certain proteases and promotes the growth of blood vessels.Nowadays,anti-vascular endothelial growth factor(VEGF)drug Conbercept has become the main drug for the treatment of CNV lesions of various causes.At present,the comparative study of the efficacy of intravitreal injection of Conbercept in the treatment of PM and AMD remains blank.In summary,in this study,we first propose a windowed active contour model to segment the CNV in the OCT image by combining the fractional enhancement and the local fuzzy energy functional.Secondly,combined with the active contour model,the effect of Conbercept on the secondary CNV of PM and wAMD was analyzed.Part ? OCT retinal image lesion local window segmentation[Purpose]To establish a model for lesion segmentation in OCT images[Method]Active contour models(ACMs)are computer generated curves that move within the image to find object boundaries.The region-based ACMs use the determined image region information to guide the curve to the desired boundary iteration.For the weak boundary,the region-based ACMs can generally get a better segmentation effect,and propose a local binary fitting(LBF)model based on the active contour.[Result]The corresponding parameters are set as follows:m = 2,?1 = ?2 =1,? = ? = 1,v = 0.2,and the proposed algorithm can segment the lesion well.[Conclusion]Based on fractional differential enhancement and local energy functionals,the windowed pre-segmentation retinal OCT lesion segmentation algorithm is very suitable for ophthalmic clinical auxiliary examination and diagnosis.Part ? Clinical study of Compaqep in the treatment of CNV[Objective]To observe the clinical efficacy and safety of intraperitoneal injection of composcipal in the treatment of PM secondary macular choroidal neovascularization(myopia CNV,mCNV)and wAMD secondary CNV.[Methods]The research was conducted on 19 eyes of 19 patients with PM and 31 eyes of 31 patients with AMD.They received intravitreal conbercept 0.5ml every month,the follow-up visits were performed monthly after injection(3+prn).Collected data included:best-corrected visual acuity(BCVA),centre macular thickness(CMT),subfoveal choroidal thickness(SFCT),the change of CNV,number of retreatment.[Results]The mean BCVA was apparently improved and CMT reduced from baseline after treatment at the 1st,2nd,3rd,6th,12th month(P<0.0O5),the SFCT showed no significant change,and the difference was not statistically significant(P>0.05).Compared with the baseline,the area of CNV decreased in the 3rd month and the 12th month(P<0.05),and the number of non-leakage cases increased.Based on LBF models,compared with the baseline,the cross-section area of CNV decreased in the 3rd month and the 12th month(P<0.05).The average number of injections in the PM group was 6.28±2.21,and that in the AMD group was 6.36±2.13.There was no significant difference between BCVA?CMT?CNV area change obtained by image lesion segmentation?the number of treatment in two groups before and after treatment.(P>0.05).[Conclusion]Intravitreal conbercept can improve BCVA,reduce CMT,decrease the area and leakage of CNV,in patients with CNV secondary to PM and AMD.No significant difference between the two groups treatment effect. |
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