ABSTRACT
Abstract Introduction A new method for segmenting and quantifying the macular area based on morphological alternating sequential filtering (ASF) is proposed. Previous studies show that persons with diabetes present alterations in the foveal avascular zone (FAZ) prior to the appearance of retinopathy. Thus, a proper characterization of FAZ using a method of automatic classification and prediction is a supportive and complementary tool for medical evaluation of the macular region, and may be useful for possible early treatment of eye diseases in persons without diabetic retinopathy. Methods We obtained high-resolution retinal images using a non-invasive functional imaging system called Retinal Function Imager to generate a series of combined capillary perfusion maps. We filtered sequentially the macular images to reduce the complexity by ASF. Then we segmented the FAZ using watershed transform from an automatic selection of markers. Using Hu's moment invariants as a descriptor, we can automatically classify and categorize each FAZ. Results The FAZ differences between non-diabetic volunteers and diabetic subjects were automatically distinguished by the proposed system with an accuracy of 81%. Conclusion This is an innovative method to classify FAZ using a fully automatic algorithm for segmentation (based on morphological operators) and for the classification (based on descriptor formed by Hu's moments) despite the presence of edema or other structures. This is an alternative tool for eye exams, which may contribute to the analysis and evaluation of FAZ morphology, promoting the prevention of macular impairment in diabetics without retinopathy.
ABSTRACT
BACKGROUND: Despite different telangiectasia treatments in the lower limbs, there is no method standardization for results assessment, making comparison between the existing treatments conflicting. OBJECTIVE: To compare the assessment carried out by a group of specialists with the assessment carried out by a computer program, according to clearance degree of telangiectasias during treatment by sclerotherapy. MATERIALS AND METHODS: Nineteen patients (21 studied areas) with telangiectasias of thighs and popliteal fossa were assessed, with a mean age of 37.5 (21-59) years old, all female. The pre- and posttreatment photos were standardized as per distance, light exposure, and aperture time. The sclerotherapy sessions were performed with 75% glucose. The clearance degree of telangiectasias was judged by a group of six doctors and by a computer program that analyzed the initial and final photos. The results of such assessment were compared according to concordance and correlation. RESULTS: There was no statistical difference between the assessments carried out by the specialists and the assessments carried out by the computer program according to the sclerotherapy results. CONCLUSION: The assessment carried out by the computer program was equivalent to the assessment carried out by the specialists in the judgment of clearance degree of telangiectasias of the lower limbs.