Purpose: To investigate the brain iron deposits in patients with Alzheimer's disease (AD) and healthy age-matched controls using phase imaging. Materials and Methods:Twenty-six AD patients and 24 healthy controls were recruited. A three-dimensional highresolution, gradient-echo sequence was used to acquire phase data in the coronal plane. A high-pass filter was used to remove the phase variation caused by field inhomogeneity. The regions evaluated included the bilateral putamen, globus pallidus, and the head and body of the hippocampus.Results: Significantly lower phase values in both the basal ganglion and hippocampus were revealed in the AD group compared to the normal controls (P Ͻ 0.05). The phase value in the right side of the head of the hippocampus had a moderate positive correlation with the MMSE score (rϭ 0.603, P ϭ 0.000) and a negative correlation with the duration of the disease (r ϭ Ϫ0.677, P ϭ 0.013). Using Ϫ0.0972 radians as an optimal cutoff value, the sensitivity and specificity for differentiation between AD and normal controls reached 95.8 and 80.8%, respectively. Conclusion:Phase imaging proved to be a useful method for the differentiation between normal controls and AD patients. An investigation of the excessive accumulation of iron in the hippocampus may help us better understand the pathologic process and neuropsychological dysfunction of AD disease.

Background and Purpose-The intraluminal suture technique for producing middle cerebral artery occlusion in rodents is the most commonly used method for modeling focal cerebral ischemia associated with clinical ischemic stroke. Synchrotron radiation angiography may provide a novel solution to directly monitor the success of middle cerebral artery occlusion. Methods-Twenty adult Sprague-Dawley rats for middle cerebral artery occlusion models were prepared randomly with different suture head silicone coating. In vivo imaging was performed at beam line BL13W1, Shanghai Synchrotron Radiation Facility, Shanghai, China. Results-Silicone-coated suture was superior to uncoated suture for producing consistent brain infarction. Additionally, silicone coating length was an important variable controlling the extent of the ischemic lesion: infarcts affected predominantly the caudate-putamen with large variability (Ͻ2 mm), both the cortex and caudate-putamen (2-3.3 mm), and most of the hemisphere, including the hypothalamus (Ͼ3.3 mm). Conclusions-Synchrotron radiation angiography provides a useful tool to observe hemodynamic changes after middle cerebral artery occlusion, and the physical properties of suture are critical to the success of the middle cerebral artery occlusion model. (Stroke. 2012;43:888-891.)Key Words: angiography Ⅲ middle cerebral artery occlusion Ⅲ synchrotron radiation T he focal cerebral ischemia model involves the occlusion of the middle cerebral artery (MCAO) and typically results in localized brain infarction, which recapitulates many of the pathophysiological and histopathologic features of stroke. The most common technique for MCAO is the intraluminal filament model. 1 However, 1 limitation of the suture model is its high variability in infarct size. 2 Factors that contribute to such variation include differences in animal strain and weight, method of anesthesia, blood pressure, brain and body temperature, brain vascular anatomy, suture material, duration, and site of occlusion. Physical properties of the filament are important because it is the key factor that affects lesion volume 3 ; however, there is no direct evidence to confirm this principle. 4,5 Regional cerebral blood flow can be measured using autoradiography and laser Doppler flowmetry to confirm successful MCAO, but neither method can dynamically monitor changes of cerebral blood flow in deeper tissue during ischemia-reperfusion. 6,7 Synchrotron radiation angiography (SRA) may represent a novel solution to directly and dynamically monitor MCAO. 8 In the present study, we used SRA to examine if the coating length was critical for producing a highly reproducible stroke model. Materials and Methods Experimental GroupsAnimal procedures were approved by the Institutional Animal Care and Use Committee of Shanghai Jiao Tong University, Shanghai, China. Twenty male Sprague-Dawley rats (SLAC, Shanghai, China) weighing 270 to 350 g were divided into 4 groups randomly (nϭ5/group). The sutures with different physical properties were used in 4 groups t...