To be able to examine dynamic and detailed brain functions, the spatial and temporal resolution of 7 T MRI needs to improve. In this study, it was investigated whether submillimeter multishot 3D EPI fMRI scans, acquired with high-density receive arrays, can benefit from a 2D CAIPIRINHA sampling pattern, in terms of noise amplification (g-factor), temporal SNR and fMRI sensitivity. High-density receive arrays were combined with a shot-selective 2D CAIPIRINHA implementation for multishot 3D EPI sequences at 7 T. In this implementation, in contrast to conventional inclusion of extra kz gradient blips, specific EPI shots are left out to create a CAIPIRINHA shift and reduction of scan time. First, the implementation of the CAIPIRINHA sequence was evaluated with a standard receive setup by acquiring submillimeter whole brain T2 *-weighted anatomy images. Second, the CAIPIRINHA sequence was combined with high-density receive arrays to push the temporal resolution of submillimeter 3D EPI fMRI scans of the visual cortex. Results show that the shot-selective 2D CAIPIRINHA sequence enables a reduction in scan time for 0.5 mm isotropic 3D EPI T2 *-weighted anatomy scans by a factor of 4 compared with earlier reports. The use of the 2D CAIPIRINHA implementation in combination with high-density receive arrays, enhances the image quality of submillimeter 3D EPI scans of the visual cortex at high acceleration as compared to conventional SENSE. Both the g-factor and temporal SNR improved, resulting in a method that is more sensitive to the fMRI signal. Using this method, it is possible to acquire submillimeter single volume 3D EPI scans of the visual cortex in a subsecond timeframe. Overall, high-density receive arrays in combination with shot-selective 2D CAIPIRINHA for 3D EPI scans prove to be valuable for reducing the scan time of submillimeter MRI acquisitions.

中文翻译：

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进一步推动功能性MRI的时空分辨率：高密度接收阵列与镜头选择性2D CAIPIRINHA相结合，可在7 T时进行3D回波平面成像。

为了能够检查动态和详细的大脑功能，需要改进7 T MRI的时空分辨率。在这项研究中，研究了用高密度接收阵列采集的亚毫米多镜头3D EPI fMRI扫描是否可以从2D CAIPIRINHA采样模式中受益，包括噪声放大率（g因子），时间SNR和fMRI灵敏度。高密度接收阵列与镜头选择性2D CAIPIRINHA实现方案相结合，可实现7 T时的多镜头3D EPI序列。在这种实现方案中，与常规包含额外的kz梯度尖峰相比，特定的EPI镜头被遗漏以产生CAIPIRINHA偏移并减少扫描时间。首先，通过获取亚毫米级全脑T2 *加权解剖图像，以标准的接收设置评估了CAIPIRINHA序列的实现。其次，将CAIPIRINHA序列与高密度接收阵列相结合，以推动视觉皮层的亚毫米3D EPI fMRI扫描的时间分辨率。结果表明，与早期报道相比，选择击球的2D CAIPIRINHA序列可使0.5 mm各向同性3D EPI T2 *加权解剖扫描的扫描时间减少4倍。与传统的SENSE相比，将2D CAIPIRINHA实现与高密度接收阵列结合使用可提高视觉皮层的亚毫米3D EPI扫描图像的图像质量。g因子和时间SNR均得到改善，从而导致对fMRI信号更加敏感的方法。使用此方法，可以在亚秒级的时间内获取视觉皮层的亚毫米单体积3D EPI扫描。总体，