Diagnosis of Alzheimer disease (AD) can be supported by hippocampal atrophy on brain MRI. A quick and easy evaluation of the hippocampus is necessary for clinical practice.

To develop a simple visual method for a stratification of a hippocampal size in patients with AD.

We manually traced hippocampal (hipp) and temporal horn (horn) areas of both sides on a single coronal T1-weighted image (fig.) in 26 AD patients (medians: age 77 years, MMSE 19 points) and in 29 non-demented elderly subjects (68 years, MMSE 29).

Fig. 1

[Hippocampo-horn proportion on brain MRI]

Common hipp+horn areas did not differ between the AD patients and the controls. The hipp area occupies a significantly smaller proportion out of the combined hipp+horn areas in the AD patients (dx 64 %, sin 62 %) than that in the controls (dx 83 %, sin 82 %) (p < 0.00003). Individuals with the hippocampal area of 50 % and less out of the combined hipp+horn areas always had AD. This can be easily estimated by a visual comparison of two areas (hipp and horn).

The size of the hippocampus on brain MRI can be semi-quantified by the comparison of the hippocampal area with the temporal horn area.

By MSMT 1M0517, IGA MH CR NS 10369-3 and MZ0PCP2005.