The dynamics of β-amyloid deposition and related second-order physiological effects, such as regional cerebral blood flow (rCBF), are key factors for a deeper understanding of Alzheimer's disease (AD). We present longitudinal in vivo data on the dynamics of β-amyloid deposition and the decline of rCBF in two different amyloid precursor protein (APP) transgenic mouse models of AD. Using a multiparametric positron emission tomography and magnetic resonance imaging approach, we demonstrate that in the presence of cerebral β-amyloid angiopathy (CAA), β-amyloid deposition is accompanied by a decline of rCBF. Loss of perfusion correlates with the growth of β-amyloid plaque burden but is not related to the number of CAA-induced microhemorrhages. However, in a mouse model of parenchymal β-amyloidosis and negligible CAA, rCBF is unchanged. Because synaptically driven spontaneous network activity is similar in both transgenic mouse strains, we conclude that the disease-related decline of rCBF is caused by CAA.

Purpose: To introduce a highly accelerated T1-weighted magnetization-prepared rapid gradient echo (MP-RAGE) acquisition that uses wave-controlled aliasing in parallel imaging (wave-CAIPI) encoding to retain high image quality. Methods: Significant acceleration of the MP-RAGE sequence is demonstrated using the wave-CAIPI technique. Here, sinusoidal waveforms are used to spread aliasing in all three directions to improve the g-factor. Combined with a rapid (2 s) coil sensitivity acquisition and data-driven trajectory calibration, we propose an online integrated acquisition-reconstruction pipeline for highly efficient MP-RAGE imaging. Results: The 9-fold accelerated MP-RAGE acquisition can be performed in 71 s, with a maximum and average g-factor of g max ¼ 1.27 and g avg ¼ 1.06 at 3T. Compared with the state-ofthe-art method controlled aliasing in parallel imaging results in higher acceleration (2D-CAIPIRINHA), this is a factor of 4.6/1.4 improvement in g max /g avg . In addition, we demonstrate a 57 s acquisition at 7T with 12-fold acceleration. This acquisition has a g-factor performance of g max ¼ 1.15 and g avg ¼ 1.04. Conclusion: Wave encoding overcomes the g-factor noise amplification penalty and allows for an order of magnitude acceleration of MP-RAGE acquisitions. Magn Reson Med 79:401-406,

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