Atrophy of medial temporal lobes on MRI in "probable" Alzheimer's disease and normal ageing: diagnostic value and neuropsychological correlates.

TLDR

MRI demonstrates marked medial temporal lobe and hippocampal volume loss in Alzheimer’s disease compared with controls, yet routine quantitative volumetry is not yet available. The study aimed to determine whether a simple visual grading of medial temporal lobe atrophy on standard MRI can differentiate Alzheimer’s patients from age‑matched controls. MTA was scored using a ranking system and cross‑validated with linear measurements of the medial temporal lobe, hippocampal formation, and adjacent cerebrospinal fluid spaces. Alzheimer’s patients exhibited significantly greater subjective and linear MTA, which correlated with MMSE and memory scores but not with mental speed, and MTA assessment on plain MRI offers a rapid, supportive diagnostic marker that appears earlier than generalized brain atrophy.

Abstract

Magnetic resonance imaging (MRI) has shown a great reduction in medial temporal lobe and hippocampal volume of patients with Alzheimer9s disease as compared to controls. Quantitative volumetric measurements are not yet available for routine clinical use. We investigated whether visual assessment of medial temporal lobe atrophy (MTA) on plain MRI films could distinguish patients with Alzheimer9s disease (n = 21) from age matched controls (n = 21). The degree of MTA was ascertained with a ranking procedure and validated by linear measurements of the medial temporal lobe including the hippocampal formation and surrounding spaces occupied by cerebrospinal fluid. Patients with Alzheimer9s disease showed a significantly higher degree of subjectively assessed MTA than controls (p = 0.0005). Linear measurements correlated highly with subjective assessment of MTA and also showed significant differences between groups. Ventricular indices did not differ significantly between groups. In Alzheimer9s disease patients the degree of MTA correlated significantly with scores on the mini-mental state examination and memory tests, but poorly with mental speed tests. This study shows that MTA may be assessed quickly and easily with plain MRI films. MTA shown on MRI strongly supports the clinical diagnosis of Alzheimer9s disease, is related to memory function, and seems to occur earlier in the disease process than does generalised brain atrophy.