The perfusion parameters cerebral blood flow (CBF) and arterial transit time (ATT) measured with arterial spin labeling (ASL) magnetic resonance imaging (MRI) provide valuable essentials to assess the integrity of cerebral tissue. Brain perfusion changes, due to aging, an intervention, or neurodegenerative diseases for example, could be investigated in longitudinal ASL studies with reliable ASL sequences. Generally, pseudo-continuous ASL (pCASL) is preferred because of its larger signal-to-noise ratio (SNR) compared to pulsed ASL (PASL) techniques. Available pCASL versions differ regarding their feature details. To date only little is known about the reliability and reproducibility of CBF and ATT measures obtained with the innovative Hadamard encoded pCASL variant, especially if applied on participants in old age. Therefore, we investigated an in-house developed Hadamard encoded pCASL sequence on a group of healthy elderly at two different 3 Tesla Siemens MRI systems (Skyra and mMR Biograph) and evaluated CBF and ATT reliability and reproducibility for several regions-of-interests (ROI). Calculated within-subject coefficients of variation (wsCV) demonstrated an excellent reliability of perfusion measures, whereas ATT appeared to be even more reliable than CBF [e.g., wsCV(CBF) = 2.9% vs. wsCV(ATT) = 2.3% for a gray matter (GM) ROI on Skyra system]. Additionally, a substantial agreement of perfusion values acquired on both MRI systems with an inter-session interval of 78 ± 17.6 days was shown by high corresponding intra-class correlation (ICC) coefficients [e.g., ICC(CBF) = 0.704 and ICC(ATT) = 0.754 for a GM ROI]. The usability of this novel Hadamard encoded pCASL sequence might improve future follow-up perfusion studies of the aging and/or diseased brain.

中文翻译：

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Hadamard 编码的伪连续动脉自旋标记在健康老年人中的可靠性和可重复性。

用动脉自旋标记 (ASL) 磁共振成像 (MRI) 测量的灌注参数脑血流量 (CBF) 和动脉传输时间 (ATT) 为评估脑组织的完整性提供了宝贵的要素。例如，由于衰老、干预或神经退行性疾病导致的脑灌注变化，可以在具有可靠 ASL 序列的纵向 ASL 研究中进行研究。通常，伪连续 ASL (pCASL) 是首选，因为与脉冲 ASL (PASL) 技术相比，它具有更大的信噪比 (SNR)。可用的 pCASL 版本在功能细节方面有所不同。迄今为止，关于使用创新的 Hadamard 编码的 pCASL 变体获得的 CBF 和 ATT 测量的可靠性和可重复性知之甚少，特别是如果应用于老年参与者。所以，我们在两个不同的 3 Tesla Siemens MRI 系统（Skyra 和 mMR Biograph）上研究了一组健康老年人的内部开发的 Hadamard 编码的 pCASL 序列，并评估了几个感兴趣区域 (ROI) 的 CBF 和 ATT 可靠性和可重复性。计算出的受试者内变异系数 (wsCV) 证明灌注测量具有出色的可靠性，而 ATT 似乎比 CBF 更可靠 [例如，对于灰色，wsCV(CBF) = 2.9% vs. wsCV(ATT) = 2.3% Skyra 系统上的物质 (GM) 投资回报率]。此外，高相应的类内相关 (ICC) 系数 [例如，ICC(CBF) = 0.704 和 ICC(ATT) ) = 0.754 对于 GM ROI]。