High-throughput, fully automated volumetry for prediction of MMSE and CDR decline in mild cognitive impairment

Abstract

Medial temporal lobe (MTL) atrophy is associated with increased risk for conversion to Alzheimer disease, but manual tracing techniques and even semiautomated techniques for volumetric assessment are not practical in the clinical setting. In addition, most studies that examined MTL atrophy in Alzheimer disease have focused only on the hippocampus. It is unknown the extent to which volumes of amygdala and temporal horn of the lateral ventricle predict subsequent clinical decline. This study examined whether measures of hippocampus, amygdala, and temporal horn volume predict clinical decline over the following 6-month period in patients with mild cognitive impairment (MCI). Fully automated volume measurements were performed in 269 MCI patients. Baseline volumes of the hippocampus, amygdala, and temporal horn were evaluated as predictors of change in Mini-mental State Examination and Clinical Dementia Rating Sum of Boxes over a 6-month interval. Fully automated measurements of baseline hippocampus and amygdala volumes correlated with baseline delayed recall scores. Patients with smaller baseline volumes of the hippocampus and amygdala or larger baseline volumes of the temporal horn had more rapid subsequent clinical decline on Mini-mental State Examination and Clinical Dementia Rating Sum of Boxes. Fully automated and rapid measurement of segmental MTL volumes may help clinicians predict clinical decline in MCI patients.

Figure 1

Segmentation example for a representative MCI subject. Hippocampus is colored in gold. Amygdala is the adjacent structure colored in light blue.

Figure 2

Clinical scores at 0- and 6-month time-points for MCI patients in quartiles based on WBV-normalized MTL volumes. Means and standard errors are shown for each of the quartiles ranging from least (1) to greatest (4) suggested atrophy. For hippocampus and amygdala, the first quartile represents the group with the largest volumes. For temporal horn, the first quartile represents the group with the smallest volumes.