Regional cerebral blood flow differences in patients with mild cognitive impairment between those who did and did not develop Alzheimer's disease Kyung Won Park a, ⁎, Hyun Jin Yoon b , Do-Young Kang b , Byeong C. Kim c , SangYun Kim d, e , Jae Woo Kim a a Department of Neurology, Dong-A University College of Medicine, 1, 3-Ga Dongdaesin-dong, Seo-gu, Busan 602-715, Republic of Korea b Department of Nuclear Medicine, Dong-A University College of Medicine, 1, 3-Ga Dongdaesin-dong, Seo-gu, Busan 602-715, Republic of Korea c Department of Neurology, Chonnam National University Medical School, 8 Hak-dong, Dong-gu, Gwangju 501-757, Republic of Korea d Department of Neurology, Seoul National University College of Medicine, Seoul, Republic of Korea e Clinical Neuroscience Center, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam 463-707, Republic of Korea abstract article info Article history: Received 3 November 2010 Received in revised form 19 October 2011 Accepted 20 December 2011 Keywords: Regional cerebral blood flow Statistical parametric mapping Hypoperfusion Conversion Dementia Mild cognitive impairment (MCI) is a heterogeneous condition associated with increased risk of Alzheimer's disease (AD) and other dementias. This study aimed to identify areas of initial hypoperfusion in MCI conver- sion to AD using technetium (Tc-99m) hexamethylpropyleneamine oxime (TC-99m HMPAO) single photon emission computed tomography (SPECT) to compare baseline cerebral hypoperfusion in converted MCI and non-converted MCI patients and normal controls. Forty-nine MCI patients were recruited for brain mag- netic resonance imaging (MRI), detailed neuropsychological testing, Tc-99m HMPAO SPECT, and 1- to 2-year pe- riodic follow-up to monitor progression to dementia status. We processed SPECT images with Statistical Parametric Mapping 8 (SPM8) software and performed voxel-based statistical parametric mapping analysis. Thirty-nine of 49 MCI patients were included in our analysis. Nine patients were diagnosed with conversion to AD, on average 19.0±6.6 months after initial assessment. Compared with normal controls, converted MCI pa- tients demonstrated perfusion deficits in both parahippocampal gyri and right precuneus, and non-converted MCI patients demonstrated hypoperfusion in the left parahippocampal gyrus. Compared with non-converted MCI patients, converted MCI patients demonstrated significant hypoperfusion in both cingulate gyri and right precuneus. Our study suggests that using brain SPECT to identify initial hypoperfusion in patients with MCI may be helpful for predicting MCI patients likely to develop AD. © 2012 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Mild cognitive impairment (MCI) is a heterogeneous condition with a variety of clinical outcomes; MCI patients are at risk of devel- oping Alzheimer's disease (AD) or may be in the preclinical stage of other dementias (Petersen et al., 1999; The Canadian Study of Health and Aging Working Group, 2000; Petersen et al., 2001; Winblad et al., 2004; Borroni et al., 2006). In most hospital-based studies of MCI, 40–80% of patients who met the criteria for this condition were diagnosed with AD over a 5-year follow-up period. Because people with MCI are at increased risk for AD and other types of de- mentia compared with similarly aged individuals in the general pop- ulation, early detection and diagnosis is important, and numerous attempts have been made to identify prognostic markers in MCI. Structural magnetic resonance imaging (MRI) and functional imag- ing by single photon emission computed tomography (SPECT) or positron emission tomography (PET) are widely used as an addi- tional tool for the diagnosis of MCI and AD. However, MCI has a variety of criteria for defining cognitive impairment and various het- erogeneous etiologies. Hence, neuropsychological test scores and neuroimaging finding in patients with MCI are ambiguous. A number of biomarkers, imaging techniques, and neuropsycho- logical tests are under investigation with promising results suggestive of their predictive utility. However, insufficient evidence of their di- agnostic utility is available (Chertkow et al., 2008). Morphological MRI studies have demonstrated that higher rates of atrophy in the medial temporal regions of the hippocampus or entorhinal cortex may be good predictive markers of conversion to AD in patients with MCI. However, MRI methods require at least a 1- to 2-year follow-up period to detect morphological changes that predict con- version to AD (Jack et al., 1999; Mungas et al., 2002). Brain perfusion single photon emission computed tomography (SPECT) has also been used as an imaging biomarker of AD and offers the advantages of rela- tively low cost and ease of access, but limited studies of this imaging technique have been conducted to date. SPECT has been an important functional neuroimaging tool in diagnosing early stage AD at the MCI stage and predicting the conversion from MCI to AD (Bradley et al., 2002; Matsuda, 2007; Habert et al., 2010). In the present study, we aimed to identify areas of baseline cerebral hypoperfusion in converted MCI patients compared with non-converted MCI patients and control Psychiatry Research: Neuroimaging 203 (2012) 201–206 ⁎ Corresponding author. Tel.: + 82 51 240 2966; fax: + 82 51 245 2966. E-mail address: neuropark@dau.ac.kr (K.W. Park). 0925-4927/$ – see front matter © 2012 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.pscychresns.2011.12.007 Contents lists available at SciVerse ScienceDirect Psychiatry Research: Neuroimaging journal homepage: www.elsevier.com/locate/psychresns