The Black-White Pixels Ratio in Medial Temporal Lobe Brain Structure in Transcranial B-Images As a Measurable Marker of Alzheimer's Disease Probability: the Reproducibility Overview.

The objective of the presented study is to introduce analysis the black-white pixels ratio in medial temporal lobe (MTL) brain structure in digitized transcranial B-images using our developed software B-MODE Assist. This ratio could be a significant marker related to the echogenicity grade. In B-image, the MTL is stable anechogenic structure but increased echogenicity of surrounding cortex is detectable in the case of MTL atrophy; the atrophy predicts Alzheimer’s Disease. Within this study, a set of 97 B-images is used. There are two key goals of this pilot study; verify the reproducibility of the ratio between two observers and to show that the ratio is not much different in the case of original image in comparison with a magnified segment and using constant brightness increasing; the ratio should be independent on image resolution and brightness. To select medial temporal lobe structure, a 20mm square-shaped Region of Interest is used. The correlation coefficient r=0.69 was achieved between two independent, non-experienced observers. The error does not exceed 28 % between 2 non-experienced observers and does not exceed 12 % between the measurements from the same observer. Also, the variance and the range were computed. Achieved results have been judged by an experienced sonographer. In the future, the ratio could be an effective value to determine the MTL atrophy based on the ratio value and possibility to create a rule-based expert system which should help evaluate probability of Alzheimer’s Disease based on the cortex echogenicity grade. In general, this approach could be a reliable way to detect risk of Alzheimer’s Disease using neurosonological imaging.