Evaluation and clinical correlation of practical cut-offs for visual rating scales of atrophy: normal aging versus mild cognitive impairment and Alzheimer’s disease

Abstract

Age-related brain atrophy is a common finding, but neurodegenerative diseases such as Alzheimer's disease are associated with accelerated atrophy of the medial temporal lobe. In current practice for brain atrophy evaluation, several rating scales are being used such as the medial temporal atrophy (MTA), global cortical atrophy-frontal subscale (GCA-F) and posterior atrophy (PA) scales. Practical cut-offs to differentiate between normal and advanced brain atrophy are needed, because of their possible usefulness as a biomarker. A retrospective study was performed over a 1-year period resulting in a total of 79 subjects [27 patients with Alzheimer's disease (AD), 27 patients with minimal cognitive impairment (MCI) and 25 control subjects]. The MTA, GCA-F and PA scales were applied blinded and independent by two raters. Possible age- and disease-related cut-offs were computed. The MTA scale showed significantly better diagnostic performances and inter-rater agreement than the PA and GCA-F scales. We could not confirm the suggested MTA cut-off for each decade. However, an MTA score of >1 and >1.75 was considered pathological, respectively, in the population under and over 70 years. MTA can be of use in making distinction between age-related atrophy and abnormal increase of atrophy. Systematic assessment of regional brain atrophy through the use of MTA in MRI images could be a useful biomarker in aiding the early diagnosis of Alzheimer's disease.

Structural imaging findings on non-enhanced computed tomography are severely underreported in the primary care diagnostic work-up of subjective cognitive decline

“…Only a few studies have shown that the scales are applicable to NECT in clinical practice [9, 10, 14, 34]. Previous studies have shown an intra-rater agreement varying from moderate to strong for MTA and PCA [9, 11, 13, 17, 35, 36]. For WMC and GCA, intra-rater agreement have been substantial to strong in previous studies [9–11, 19].…”

Validity and reliability of the medial temporal lobe atrophy scale in a memory clinic population

“…The variation of proposed cut-off values in studies may naturally also be affected by the subjective nature of the MTA scale. A smaller study reported different optimal cut-off values set by the two raters [ 50 ], even though inter-rater correlations were high. The accuracy of the MTA cut-off increased when the average between the two raters were used.…”

A Large-scale Comparison of Cortical and Subcortical Structural Segmentation Methods in Alzheimer’s Disease: a Statistical Approach

“…Therefore, a massive effort has been devoted to the development of diagnostic methods to enable researchers and clinicians to detect AD and cases with potential progression to AD, as early as possible 132,133 . For the development of preventive strategies, it is important to predict future brain atrophy, as this may aid in identifying which individuals with normal cognition are more susceptible of progressing to later stages of AD [134][135][136] . Automated systems provide additional information to clinicians, enabling them to have a greater understanding of the progression of the atrophy 12,137 .…”