Consistency Of Different Image Analysis Modes On Quantizing Dna Degradation Status Of Human Splenic Lymphocytes And Deducing Pmi

To evaluate the stability of Image Analysis Technique (IAT) on deducing the postmortem interval (PMI), we quantitatively analyzed DNA degradation status of human splenic lymphocytes by using the same acquisition mode but different image analysis systems(IAS). We selected 21 cadavers whose accurate PMI were known, samples were smeared respectively every hour from the first 5 to 36 hours after death. The smears stained by Feulgen-van's method, collected images by the same image analysis systems (Motic Med 6.0 CMIAS) and analyzed the images with two different image analysis systems (HAPIS-1000 and Motic Med 6.0 CMIAS). The geometric parameters (A, ED, ID) and grayscale parameters (AG, AOD, IOD) which were owned by both image analysis modes of the different IAS as detect indexes, took the mean of the data of 3150 cells as each statistic. The differences between the two groups of measured means of same kind parameter under the different image analysis systems were compared. We found the corresponding means of same grayscale parameters statistic different between two different image analysis systems, while no statistic difference was found within geometric parameters. Whatever, converted the means of grayscale parameters into percentages, no statistic difference was found between two groups. So, analyzing geometric parameters with different image analysis modes is stable and reliable. As to grayscale parameters, the stability could be affected by different image analysis modes. In fact, having the same intrinsic basic rules of statistic analysis and calculation about two image analysis modes, both grayscale and geometric methods could reflect the regularity of DNA degradation status effectively after proper conversion or calibration.