Mild cognitive impairment and alzheimer disease: patterns of altered cerebral blood flow at MR imaging

Abstract

Purpose: To examine regional cerebral blood flow (rCBF) in incident mild cognitive impairment (MCI) and Alzheimer disease (AD) by using continuous arterial spin-labeling (CASL) magnetic resonance (MR) imaging.

Materials and methods: This study was approved by the local institutional review board and was compliant with HIPAA regulations. Informed consent was obtained. rCBF was measured in 38 control subjects, 29 MCI patients, and 37 AD patients who were participating in a longitudinal epidemiologic study. Multisection CASL MR imaging with alternating single and double adiabatic inversion pulses and ramp-sampled echo-planar imaging were performed to acquire 19 contiguous axial sections. Voxel-level rCBF was compared among groups by using an analysis of variance design; clusters of voxels with significant group differences were identified. Multiple regression models controlled for age, sex, and presence of hypertension and related the mean rCBF in those clusters to the presence of MCI and AD.

Results: MCI and AD patients had decreased rCBF in the posterior cingulate gyrus (P = .01) with extension to the medial precuneus compared with that in control subjects. MCI patients had increased rCBF in the left hippocampus (P < .001), right amygdala (P = .007), and rostral head of the right caudate nucleus and ventral putamen and globus pallidus (P = .003) compared with that in control subjects. AD patients had decreased rCBF relative to that in control subjects and MCI patients in the left inferior parietal (P = .005), left lateral frontal (P < .001), left superior temporal (P = .001), and left orbitofrontal (P = .003) cortices. AD patients had increased rCBF in the right anterior cingulate gyrus (P = .02) compared with that in control subjects.

Conclusion: The transition from normal cognition to AD is associated with dynamic pathologic processes in the brain, and this is reflected by both decreases and increases in rCBF. Increases in rCBF suggest a cellular and vascular compensatory process associated with incipient AD.

Supplemental material: http://radiology.rsnajnls.org/cgi/content/full/2503080751/DC1.

Figure 1:

Chart of MR imaging of the brain in participants of the Cardiovascular Health Study Cognition Study. All participants underwent MR imaging of the brain between 1992 and 1994 and between 1998 and 1999. A third MR imaging examination was performed in 150 participants between 2002 and 2003. * = See Participant section for exclusion details.

Figure 2:

A–D, Images show statistically significant clusters (with a corrected cluster level of P < .05) according to analysis of variance overlaid in color on the surface section of the colin27 brain. Yellow indicates the most significant difference in rCBF. Images show sagittal, coronal, and axial planes from left to right.

Figure 3:

A–F, Images show statistically significant clusters (with a corrected cluster level of P < .05) according to analysis of variance overlaid in color on the surface section of the colin27 brain. Yellow indicates the most significant difference in rCBF. Images show sagittal, coronal, and axial planes from left to right.

Figure 4:

A–E, Images show statistically significant clusters (with a corrected cluster level of P < .05) according to analysis of variance overlaid in color on the surface section of the colin27 brain. Yellow indicates the most significant difference in rCBF. Images show sagittal, coronal, and axial planes from left to right.

Figure 5:

rCBF z scores in patients with MCI and early AD relative to control subjects. L = left, R = right, ACG = anterior cingulate gyrus, Amyg = amygdala, BG = basal ganglia (ventral caudate nucleus, globus pallidus, and putamen), Hipp = hippocampus, IP = inferior parietal cortex, LF = lateral frontal cortex, OF = orbitofrontal cortex, PCG = posterior cingulate gyrus with extension to the precuneus; SP = superior parietal cortex, ST = superior temporal cortex, Thal = thalamus.