Current Medicine Research and Practice (Jan 2012)
Utility of cerebral perfusion SPECT in the diagnosis of mild cognitive impairment
Abstract
Background: Mild cognitive impairment (MCI), an intermediate state between normal ageing and dementia, is characterized by acquired cognitive deficits, without significant decline in functional activities of daily living. Functional imaging techniques have demonstrated regional abnormalities in brain metabolism/brain perfusion in patients with MCI. Objectives: We assessed changes in regional cerebral blood flow (rCBF) in patients presenting with MCI using99mTc ECD-SPECT. Materials and Methods: This study included 35 subjects with clinical suspicion of MCI and 20 age-matched controls. They were evaluated clinically with complete neuropsychological assessment. SPECT examination was also done using99mTC-ECD with a dual-head gamma camera equipped with a fan beam collimator. The resulting images were reconstructed and evaluated both visually and by semi-quantitative assessment. The cortical regions were compared with the cerebellum and cortical/ cerebellar ratios were calculated. Results: A significant reduction in cerebral cortical perfusion was found in the prefrontal, parietal and temporal cortices of the subjects with MCI, with preserved perfusion in the superior frontal, sensory-motor, occipital, thalami, basal ganglia and the cerebellum. On semi-quantitative assessment, this hypoperfusion was found to be more significant on the left side. No statistically significant perfusion abnormality was noted in the control group. Conclusion: Assessment of cerebral perfusion SPECT in patients with clinical suspicion of MCI would not only be helpful in detecting areas of hypoperfusion (thereby aiding the clinical diagnosis), but would also serve as a baseline study for future comparisons and evaluation of disease progression.
