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| Figure showing the areas needed to calculate the MTAi: (A-B) x10 / C A: the medial temporal lobe region B: the parenchima within the medial temporal region, that includes the hippocampus and the parahippocampal girus C: the body of the ipsilateral lateral ventricle |
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| Example of the Medial Temporal Atrophy index (MTAi) in a patient with mild AD. A. The coronal TIR MRI at the interpeduncular fosa is taken. B. Areas traced according to Figure 1. The data needed to compute the index are underlined in colors as in the previous figure. Note how the right MTAi is clearly higher than the left MTAi in this patient. |
The authors propose using a routine clinically-acquired coronal T1-weighted scan together with a readily-available measurement tool found on most modern clinical radiologic image viewing programs as a (sort of) fast and easy alternative to computationally and time-intensive volumetric calculations for evaluation of medial temporal lobe atrophy (MTA). Their stated purpose is to identify -and quantify- the degree of MTA for clinical purposes, to aid treating physicians in knowing when atrophy is clinically significant.
ReplyDeleteTHe actual method involves comparing the area of the lateral ventricle in the mid-temporal lobe as measured on a single coronal slice to the area of the lateral ventricle as measured on that same slice. They perform a substraction of the volume of the hippocampus+parahippocampal region from the total area of all voxels with the region of ventricle+hippocampal complex.
I find this method really convenient to be used in daily clinical practice as a tool assessing MTA objectively.