Visual assessment of posterior atrophy development of a MRI rating scale.

Objective: To develop a visual rating scale for posterior atrophy (PA) assessment and to analyse whether this scale aids in the discrimination between Alzheimer's disease (AD) and other dementias.

Methods: Magnetic resonance imaging of 118 memory clinic patients were analysed for PA (range 0-3), medial temporal lobe atrophy (MTA) (range 0-4) and global cortical atrophy (range 0-3) by different raters. Weighted-kappas were calculated for inter- and intra-rater agreement. Relationships between PA and MTA with the MMSE and age were estimated with linear-regression analysis.

Results: Intra-rater agreement ranged between 0.93 and 0.95 and inter-rater agreement between 0.65 and 0.84. Mean PA scores were higher in AD compared to controls (1.6  ±  0.9 and 0.6  ±  0.7, p  <  0.01), and other dementias (0.8 ± 0.8, p  <  0.01). PA was not associated with age compared to MTA (B = 1.1 (0.8) versus B = 3.1 (0.7), p  <  0.01)). PA and MTA were independently negatively associated with the MMSE (B = -1.6 (0.5), p  <  0.01 versus B = -1.4 (0.5), p  <  0.01).

Conclusion: This robust and reproducible scale for PA assessment conveys independent information in a clinical setting and may be useful in the discrimination of AD from other dementias.