Quantifying the test–retest reliability of cerebral blood flow measurements in a clinical model of on-going post-surgical pain: A study using pseudo-continuous arterial spin labelling

Abstract

Arterial spin labelling (ASL) is increasingly being applied to study the cerebral response to pain in both experimental human models and patients with persistent pain. Despite its advantages, scanning time and reliability remain important issues in the clinical applicability of ASL. Here we present the test–retest analysis of concurrent pseudo-continuous ASL (pCASL) and visual analogue scale (VAS), in a clinical model of on-going pain following third molar extraction (TME). Using ICC performance measures, we were able to quantify the reliability of the post-surgical pain state and ΔCBF (change in CBF), both at the group and individual case level. Within-subject, the inter- and intra-session reliability of the post-surgical pain state was ranked good-to-excellent (ICC > 0.6) across both pCASL and VAS modalities. The parameter ΔCBF (change in CBF between pre- and post-surgical states) performed reliably (ICC > 0.4), provided that a single baseline condition (or the mean of more than one baseline) was used for subtraction. Between-subjects, the pCASL measurements in the post-surgical pain state and ΔCBF were both characterised as reliable (ICC > 0.4). However, the subjective VAS pain ratings demonstrated a significant contribution of pain state variability, which suggests diminished utility for interindividual comparisons. These analyses indicate that the pCASL imaging technique has considerable potential for the comparison of within- and between-subjects differences associated with pain-induced state changes and baseline differences in regional CBF. They also suggest that differences in baseline perfusion and functional lateralisation characteristics may play an important role in the overall reliability of the estimated changes in CBF. Repeated measures designs have the important advantage that they provide good reliability for comparing condition effects because all sources of variability between subjects are excluded from the experimental error. The ability to elicit reliable neural correlates of on-going pain using quantitative perfusion imaging may help support the conclusions derived from subjective self-report.

Reliability comparison of spontaneous brain activities between BOLD and CBF contrasts in eyes-open and eyes-closed resting states

“…In alignment to several previous test-retest reliability studies of average CBF (Hodkinson et al, 2013;Jahng et al, 2005; Jann et al, 2014), we showed excellent reliability of CBF-mean almost across the whole brain in both EO and EC states. Consistent with previous reliability investigations of BOLD-ALFF in EO (Kublbock et al, 2014;Zuo et al, 2010a), we observed high reliability in the gray matter and most white matter regions and extended the findings to both EO and EC resting states.…”

“…Test-retest reliability of CBF-mean, BOLD-and CBF-ALFF, and BOLD-and CBF-FC For CBF-mean, consistent with previous voxel-wise test-retest studies (Hodkinson et al, 2013;Jahng et al, 2005;Jann et al, 2014), we showed that both short-and long-term ICC were excellent (ICC N 0.6) for almost the entire brain volume, especially in the gray matter in both EO and EC states (Figs. 2, 3 and S1).…”

“…It is of crucial importance to evaluate the test-retest reliability of brain activity measures and build human brain function studies on these reliable measures (Hodkinson et al, 2013;Jahng et al, 2005;Jann et al, 2014;Kublbock et al, 2014;Marcus, 2014;Patriat et al, 2013;Shehzad et al, 2009;Zhu et al, 2014;Zuo et al, 2010aZuo et al, ,b,c, 2013Zuo and Xing, 2014). In alignment to several previous test-retest reliability studies of average CBF (Hodkinson et al, 2013;Jahng et al, 2005; Jann et al, 2014), we showed excellent reliability of CBF-mean almost across the whole brain in both EO and EC states.…”

“…Previous investigations on test-retest reliability of spontaneous BOLD signal oscillations (Kublbock et al, 2014;Zuo et al, 2010a) showed that regions with high reliability were mainly located in the gray matter. Similar results were observed by separate studies investigating test-retest reliability of average CBF (Hodkinson et al, 2013;Jahng et al, 2005;Jann et al, 2015). One recent study compared shortterm test-retest reliability of CBF-mean, functional connectivity based on BOLD and CBF time series, which showed generally more reliable spatial patterns of functional connectivity of BOLD than that of CBF, while the highest reproducibility was yielded by CBF-mean (Jann et al, 2015).…”

“…Thus they are of crucial importance to evaluate the test-retest reliability of brain activity measures (Hodkinson et al, 2013;Jahng et al, 2005;Jann et al, 2014;Kublbock et al, 2014;Patriat et al, 2013;Shehzad et al, 2009;Zhu et al, 2014;Zuo et al, 2010aZuo et al, ,b,c, 2013Zuo and Xing, 2014). Resting-state fMRI, including blood oxygenation level dependent (BOLD) and arterial spin labeling (ASL), has become a powerful tool in mapping human brain functions (Biswal et al, 2010;Smith et al, 2013).…”