Regional Reliability of Quantitative Signal Targeting with Alternating Radiofrequency (STAR) Labeling of Arterial Regions (QUASAR)

• DOI: 10.1111/jon.12076
• Publication Date: 2014-02-24T17:52:24Z
• Authors: Yasuko Tatewaki; Shuichi Higano; Yasuyuki Taki; Benjamin Thyreau; Takaki Murata; Shunji Mugikura; Daisuke Ito; Kei Takase; Shoki Takahashi
• Keywords: Adult; Male; Radio Waves; Brain; Reproducibility of Results; Image Enhancement; Sensitivity and Specificity; White Matter; Young Adult; 03 medical and health sciences; Imaging, Three-Dimensional; 0302 clinical medicine; Clinical Investigative Study; Reference Values; Cerebrovascular Circulation; Image Interpretation, Computer-Assisted; Humans; Female; Spin Labels; Gray Matter; Blood Flow Velocity; Magnetic Resonance Angiography

ABSTRACTBACKGROUND AND PURPOSEQuantitative signal targeting with alternating radiofrequency labeling of arterial regions (QUASAR) is a recent spin labeling technique that could improve the reliability of brain perfusion measurements. Although it is considered reliable for measuring gray matter as a whole, it has never been evaluated regionally. Here we assessed this regional reliability.METHODSUsing a 3‐Tesla Philips Achieva whole‐body system, we scanned four times 10 healthy volunteers, in two sessions 2 weeks apart, to obtain QUASAR images. We computed perfusion images and ran a voxel‐based analysis within all brain structures. We also calculated mean regional cerebral blood flow (rCBF) within regions of interest configured for each arterial territory distribution.RESULTSThe mean CBF over whole gray matter was 37.74 with intraclass correlation coefficient (ICC) of .70. In white matter, it was 13.94 with an ICC of .30. Voxel‐wise ICC and coefficient‐of‐variation maps showed relatively lower reliability in watershed areas and white matter especially in deeper white matter. The absolute mean rCBF values were consistent with the ones reported from PET, as was the relatively low variability in different feeding arteries.CONCLUSIONSThus, QUASAR reliability for regional perfusion is high within gray matter, but uncertain within white matter.