Notes
The medial temporal atrophy score
The medial temporal atrophy score aims to help identifying and distinguishing patients with Alzheimer disease from those with cognitive impairment due to other causes.
The score has the following grades:
- 0 (normal) – choroid fissure is not widened
- 1 – slight widening of the choroid fissure
- 2 – moderate widening of the choroid fissure, mild temporal horn enlargement and hippocampal height loss
- 3 – marked widening of the choroid fissure, moderate temporal horn enlargement and hippocampal height loss
- 4 – marked widening of the choroid fissure, marked temporal horn enlargement and hippocampal height loss
The age of the patient must be considered while interpreting the score:
- <75 years: a score ≥2 is abnormal
- ≥75 years: ≥3 is abnormal
Recently a more detailed cut-off was proposed for the average(!) MTA score:
- <65 years: ≥1 is abnormal
- 65-74: ≥1.5
- 75-84: ≥2
- >85: ≥2 (but low – 62.5% – specificity in this age group!)
Note however that according to more recents studies both gender and education are potential confounders of the MTA score. Furthermore, it has been shown that the effect of age considerably slows down on the medial temporal atrophy score after the age of 80. Thus, a more recent study by Claus et. al warns that the MTA cut-off has limited use after the age of 85.
Technical considerations
Originally the medial temporal atrophy score was described using MRI (coronal, T1-weighted parallel to the axis of the brainstem and hippocampus, at the level of the anterior pons), but is has been validated for use on CT too.
The right and left side is scored separately. Individual scores for each side, the average, or the higher score has all been used by various authors in the peer-reviewed literature. This calculator reports the score for each side separately.
Limitations
Entorhinal cortex atrophy is not included in the medial temporal atrophy score. Thus, the entorhinal cortical atrophy (ERICA) scoring system was developed to address this issue, and help differentiating patients with Alzheimer disease.
Further reading
Radiopaedia.org article (includes examples of the different grades)
For grading of global cortical atrophy consider using the Pasquier scale.
Last updated: 2022-03-18