High Resolution Imaging of the Medial Temporal Lobe in Alzheimer's Disease and Dementia with Lewy Bodies

Abstract

Abstract. We used high resolution (0.3 mm in-plane) coronal 3T magnetic resonance (MR) imaging of the medial temporal lobe in 16 subjects with Alzheimer's disease (AD), 16 with dementia with Lewy bodies (DLB), and 16 similarly aged healthy subjects. On the anterior section of the hippocampus body, regions of interest were manually drawn blind to diagnosis on the CA1, CA2, and CA3/4 subregions, and the width of the subiculum and entorhinal cortex was measured. Controlling for intracranial volume, age, and years of education, we found the subiculum thickness was significantly reduced in AD (2.03 ± 0.29 mm) compared to both control (2.37 ± 0.28 mm, p = 0.008) and DLB (2.35 ± 0.24 mm, p = 0.001) subjects. The area of CA1 was likewise reduced in AD compared to controls and DLB. In the hippocampus images, a hypointense line is visible between CA1 and CA3/4. This line was significantly less distinct in AD, suggesting disease related changes to this region. Future studies should investigate whether subiculum thickness or the hypointense line could be a diagnostic feature to help discriminate AD from DLB.

Application of the VSRAD, a Specific and Sensitive Voxel-Based Morphometry, to Comparison of Entorhinal Cortex Atrophy between Dementia with Lewy Bodies and Alzheimer’s Disease

“…As mentioned earlier, two studies [6,7] reported no significant difference in the degree of entorhinal cortex atrophy between DLB and AD. The present study applied the VSRAD, an automatic and objective morphometry targeting this region, to a large number of patients (n = 270), while the two studies used manual measurements in relatively small numbers of patients (n = 32 and 46).…”

“…However, very few studies have focused on the entorhinal cortex. To date, only two studies have compared the volume [6] or thickness [7] of this structure between DLB and AD. These studies reported no significant difference between the two types of dementia, which is rather surprising in light of the significant difference in other structures of the medial temporal lobe [3][4][5].…”

“…It is often difficult to quantify the entorhinal cortex due to its small size and variation in length [7]. The two studies mentioned above used manual measurements, which are time-consuming, have the problem of objectivity and produce interrater variations [4].…”

Entorhinal cortex: a good biomarker of mild cognitive impairment and mild Alzheimer’s disease

“…Although the atrophy of EC can be a sensitive predictor for early diagnosis (Devanand et al, 2007), it can be very challenging to determine the location of the EC boundary because of its small size (Marui et al, 2004;Firbank et al, 2010;Price et al, 2010). EC lies adjacent to the amygdala and hippocampus and forms the major portion of the anterior parahippocampal gyrus .…”

What can imaging tell us about cognitive impairment and dementia?

“…The rate of progressive atrophy is increased when compared to normal controls, exaggerated if AD co-exists, but much lower compared to AD. Visual hallucinations and visuoperceptual deficits, a characteristic feature of LBD do not seem to correlate with occipital lobe involvement [85] . However, correlation with other regions involved in visual processing (visual association areas) and executive functions (inferior frontal lobe) have been reported.…”