Reliability and precision of pseudo‐continuous arterial spin labeling perfusion MRI on 3.0 T and comparison with ¹⁵O‐water PET in elderly subjects at risk for Alzheimer's disease

Abstract

Arterial spin labeling (ASL) offers MRI measurement of cerebral blood flow (CBF) in vivo, and may offer clinical diagnostic utility in populations such as those with early Alzheimer's disease (AD). In the current study, we investigated the reliability and precision of a pseudo-continuous ASL (pcASL) sequence that was performed two or three times within one hour on eight young normal control subjects, and 14 elderly subjects including 11 with normal cognition, one with AD and two with Mild Cognitive Impairment (MCI). Six of these elderly subjects including one AD, two MCIs and three controls also received 15 O-water positron emission tomography (PET) scans 2 h before their pcASL MR scan. The instrumental reliability of pcASL was evaluated with the intraclass correlation coefficient (ICC). The ICCs were greater than 0.90 in pcASL global perfusion measurements for both the young and the elderly groups. The cross-modality perfusion imaging comparison yielded very good global and regional agreement in global gray matter and the posterior cingulate cortex. Significant negative correlation was found between age and the gray/ white matter perfusion ratio (r ¼ -0.62, p < 0.002). The AD and MCI patients showed the lowest gray/white matter perfusion ratio among all the subjects. The data suggest that pcASL provides a reliable whole brain CBF measurement in young and elderly adults whose results converge with those obtained with the traditional 15 O-water PET perfusion imaging method. pcASL perfusion MRI offers an alternative method for non-invasive in vivo examination of early pathophysiological changes in AD.

Ventromedial Prefrontal Cortex Lesions Alter Neural and Physiological Correlates of Anticipation

“…Baseline resting cerebral blood flow (CBF) was estimated using a 3D fast spin echo spiral sequence with pseudocontinuous arterial spin labeling (pcASL; Dai et al, 2008;Xu et al, 2010;Okonkwo et al, 2014) and background suppression for quantitative perfusion measurements (TR ϭ 4653 ms, TE ϭ 10.5 ms, postlabeling delay ϭ 1525 ms, labeling duration ϭ 1450 ms, 8 interleaved spiral arms with 512 samples at 62.5 kHz bandwidth and 38 4-mm-thick slices, number of excitations ϭ 3, scan duration ϭ 4.5 min).…”

Absolute quantification of perfusion by dynamic susceptibility contrast MRI using Bookend and VASO steady-state CBV calibration: a comparison with pseudo-continuous ASL

“…In the present study, steady-state CBV measurements from pre-and post-CA T1 measurements (for the Bookend approach) as well as from the VASO method were used to calibrate CBF from DSC-MRI in a test-retest study in 20 healthy subjects, and the results were compared to CBF from pseudo-continuous arterial spin labeling (pCASL). Absolute CBF values from pCASL have previously shown reasonable agreement with reference methods such as PET [11,12], and a comparison between pCASL and calibrated DSC-MRI is thus of relevance. The VASO-and Bookend-calibrated CBF estimates were also mutually compared and the repeatability of the measurements was investigated.…”

Operator-bias-free Comparison of Quantitative Perfusion Maps Acquired with Pulsed-continuous Arterial Spin Labeling and Single-photon-emission Computed Tomography

“…Most studies comparing ASL and other brain perfusion methods have set ROIs manually on the CBF map, 12,[16][17][18] but the manual setting of ROIs introduces inter-rater variability, which is avoided using 3DSRT because the software automatically draws the segmented ROI after registration to an anatomically standardized brain image. In our study, use of 3DSRT allowed detailed comparison in each region of the brain.…”

“…Good agreements have already been found between CBF obtained by pCASL at 3.0 tesla and other modalities, such as positron emission tomography (PET) and dynamic susceptibility contrast (DSC) MR imaging. 12,13 Iodine-123-N-isopropyl-p-iodoamphetamine (IMP) single photon emission computed tomography (SPECT) using autoradiography (ARG) is an established standard method to assess CBF, with substantial evidence accumulated in nuclear medicine. It is known that CBF values show good correlation between IMP SPECT and PET using H 2 15 O or C 15 O 2 .…”

“…Good agreement has been reported between ASL and nuclear medicine studies. 12,[16][17][18] However, these studies have usually involved the manual setting of regions of interest (ROI) on the CBF map, introducing inter-rater variability and making detailed comparisons of brain regions difficult.…”