SCD is a genetic blood disorder characterized by abnormal hemoglobin S (HbS) synthesis with sickle cell anemia (SCA) as the most common subtype. Stroke is the most frequent cause of death and long-term disability in both children and adults with SCD. Studies of patients with focal neurologic deficits have revealed abnormalities of both large and small vessels in SCD. Currently, the main clinical screening test is the use of transcranial Doppler (TCD) for neurologically asymptomatic children with SCD. The TCD test has a low positive predictive value and is not effective to screen stroke risk in adult SCD patients. Cerebral blood flow (CBF), a measure of the microvascular perfusion of the brain, has been recognized as a potentially more sensitive and specific indicator of early cerebrovascular impairment in both children and adults with SCD. CBF measurement based on the arterial spin labeling (ASL) MRI technique is promising as it does not require a contrast agent and is free of radiation. However, the existing ASL techniques often acquire 2D multi-slice perfusion-weighted MRI at a single post-labeling delay and, for CBF calculation, make assumptions on a number of parameters that are related to blood properties, such as arterial arrival time (AAT), longitudinal relaxation time (T1) of blood and labeling efficiency. The overall goal of the research proposed is to develop and validate a multi-delay 3D ASL protocol combined with per-subject measurements of blood T1 and labeling efficiency, which provides accurate and reliable perfusion metrics (CBF and AAT) for SCD patients. The measured CBF and AAT are expected to allow detection of both small and large vessel disease simultaneously for SCD.
The specific aims of this study is first to develop a comprehensive and fast ASL-based perfusion protocol and demonstrate its reliability and reproducibility in healthy volunteers (Aim 1), then to validate the measured CBF and AAT with phase-contrast MR Angiography (PC-MRA) and dynamic susceptibility contrast (DSC) MRI in a group of SCA patients without a history of stroke (Aim 2), and finally to monitor CBF and AAT in patients with SCD and a history of stroke to explore the association between CBF and AAT and recurrent brain injury (Aim 3).
Sickle Cell Disease (SCD) is associated with high stroke risks for both children and adults. Earlier identification of affected patients at risk for neurovascular crisis can help clinicians to adjust management to prevent escalation of cerebral circulatory abnormality. This project proposes to develop and validate a fast noninvasive MRI protocol for cerebral blood flow measurement, which holds potential to facilitate stroke risk screening.
|Hua, Jun; Liu, Peiying; Kim, Tae et al. (2018) MRI techniques to measure arterial and venous cerebral blood volume. Neuroimage :|
|Li, Wenbo; Xu, Feng; Schär, Michael et al. (2018) Whole-brain arteriography and venography: Using improved velocity-selective saturation pulse trains. Magn Reson Med 79:2014-2023|
|Xu, Feng; Li, Wenbo; Liu, Peiying et al. (2018) Accounting for the role of hematocrit in between-subject variations of MRI-derived baseline cerebral hemodynamic parameters and functional BOLD responses. Hum Brain Mapp 39:344-353|
|Liu, Dexiang; Xu, Feng; Lin, Doris D et al. (2017) Quantitative measurement of cerebral blood volume using velocity-selective pulse trains. Magn Reson Med 77:92-101|
|Li, Wenbo; Liu, Peiying; Lu, Hanzhang et al. (2017) Fast measurement of blood T1 in the human carotid artery at 3T: Accuracy, precision, and reproducibility. Magn Reson Med 77:2296-2302|
|Qin, Qin; van Zijl, Peter C M (2016) Velocity-selective-inversion prepared arterial spin labeling. Magn Reson Med 76:1136-48|
|Yang, Huan; Zhang, Xuefeng; Qin, Qin et al. (2016) Improved cerebrospinal fluid suppression for intracranial vessel wall MRI. J Magn Reson Imaging 44:665-72|
|Li, Wenbo; Grgac, Ksenija; Huang, Alan et al. (2016) Quantitative theory for the longitudinal relaxation time of blood water. Magn Reson Med 76:270-81|
|Qin, Qin; Shin, Taehoon; Schär, Michael et al. (2016) Velocity-selective magnetization-prepared non-contrast-enhanced cerebral MR angiography at 3 Tesla: Improved immunity to B0/B1 inhomogeneity. Magn Reson Med 75:1232-41|
|Shin, Taehoon; Qin, Qin; Park, Jang-Yeon et al. (2016) Identification and reduction of image artifacts in non-contrast-enhanced velocity-selective peripheral angiography at 3T. Magn Reson Med 76:466-77|
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