Purpose:
To determine which quantitative method is the best for measurements of the lesion size on fluorescein angiography (FA), in patients with Age Related Macular Degeneration (AMD) .
Methods:
Patients with neovascular AMD (NAMD), were included at baseline and following treatment with 1.25mg bevacizumab were included. All patients underwent fluorescein angiography prior to and following treatment. The size of the angiographic ally defined lesions was assessed by using a previously reported method developed by the authors, SITE-App, and compared the other quantitative methods previously reported in literature: greatest linear dimension in millimeters - GLD[mm] or pixels - GLD[pix], mouse-delimited lesions area in MPS units - A[MPS], mm2 - A[mm2], total pixels - A[tpix] or white pixels A[wpix]. SITE-App quantifies the retinal lesions area in pixels (white or black), counted inside of standardized circles including the interest lesions. The measurements simplicity, reproducibility and sensitivity were compared for different methods.
Results:
The best reproducibility was demonstrated by the methods assessing the lesions size area in pixels of interest (white pixels for NAMD): SITE-App (p=0.49) and A[wpix] (p=0.22). The reproducibility was lower but still good for A[MPS] and A[mm2] (p=0.13). A[tpix] (p=0.01), GLD[pix] (p=0.0003) and GLD[mm] (p=0.0005) were found not reproducible. The highest sensitivity was observed for SITE-App (p1=0.002, p2=0.021) and A[wpix] (p1=0.007, p2=0.02), the two methods being also highly correlated (r1=0,96, r2=0,94).The other methods A[MPS] and A[mm2] were not correlated (R1=1.54±26.1, R2=3.51±17.3) and offered variable responses.
Conclusions:
Quantification of retinal lesions in pixels of interest inside zone of standardized areas (SITE-App method) is reproducible, sensitive, easy, fast, automated, and low cost . It may have applications for clinical practice and research.
Clinical Trial:
http://www.clinicaltrials.gov NCT00564148
Keywords: age-related macular degeneration • imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)