Introduction: The use of high magnetic fields in combination with fast algorithms for computer-based postprocessing has moved advanced MRI techniques into clinical practice. MRI provides in analogy with PET physiological information in addition to more traditional morphological images. Evaluation of cerebral blood flow (CBF) and also of white matter damage may be used to support the diagnosis and characterization of dementia and is of special important interest for the detection of changes in the early stages of the disease. Purpose: To investigate whether perfusion MRI with CBF maps combined with diffusion MRI with diffusion tensor imaging (DTI) and tractography analysis for the cingulum (Fig. 1) and corpus callosum (CC) can improve the diagnostic evaluation in dementia. Material and method: Retrospective study of 18 patients with suspected early dementia or dementia of unclear type investigated with an advanced 3T MRI protocol including 3D pseudocontinuous arterial spin labeling (PC ASL) sequence for CBF measurement and DTI sequence used for tractography. Fifteen of the patients have also undergone 18-FDG PET examination. A reference data set from 30 healthy volunteers was used for comparison. Asymmetry in CBF between left and right hemispheres was measured using standard regional templates. Tractography was performed and values of whole tract fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured for the left and right cingulum and CC. Results: Figure 2 shows the right/left asymmetry of CBF for different lobes for patients in comparison with controls. Five of the patients had prominent asymmetry in both frontal and temporal lobes, 4 in parietal lobes, 4 were found normal and 5 patients were difficult to classify. In 9 out of 11 patients PET confirms findings: 3 patient with suspected Alzheimer's disease (AD); 4 with suspected frontotemporal dementia (FTD), and 2 were found normal. Mean FA and ADC values in cingulum and in CC for the patient group compared with controls are presented in Table 1. ADC values in CC were higher comparing with controls and higher for patients with suspected FTD than for patients with suspected AD. Conclusion: CBF measurements and characteristics obtained by advanced MRI techniques have a potential to facilitate early diagnosis and understanding of dementia.
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European Society for Magnetic Resonance in Medicine and Biology, 2009