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Transcranial Doppler-Based Surrogates for Cerebral Blood Flow: A Statistical Study

View Article: PubMed Central - PubMed

ABSTRACT

It is commonly assumed that perfusion in a given cerebral territory can be inferred from Blood Flow Velocity (BFV) measurements in the corresponding stem artery. In order to test this hypothesis, we construct a cerebral blood flow (CBF) estimator based on transcranial Doppler (TCD) blood flow velocity and ten other easily available patient characteristics and clinical parameters. A total of 261 measurements were collected from 88 older patients. The estimator is based on local regression (Random Forest). Its performance is analyzed against baseline CBF from 3-D pseudocontinuous arterial spin labeling (pCASL) magnetic resonance imaging (MRI). Patient specific CBF predictions are of poor quality (r = 0.41 and p-value = 4.5 × 10−12); the hypothesis is thus not clearly supported by evidence.

No MeSH data available.


Left: time-of-flight MRA 3-D reconstruction; right: single-slice transverse view; bottom: zoom on the locations of three MCA radius estimates.
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pone.0165536.g001: Left: time-of-flight MRA 3-D reconstruction; right: single-slice transverse view; bottom: zoom on the locations of three MCA radius estimates.

Mentions: High resolution anatomical images were acquired through 3D magnetization prepared rapid gradient echo (MP-RAGE) and fluid attenuation inversion recovery (FLAIR). Perfusion images were averaged during each condition (6 minutes baseline normocapnia) to improve the signal-to-noise ratio. Perfusion and anatomical MR images (MP-RAGE and FLAIR) was co-registered to a standard template of regional vascular territories and segmented to calculate regional perfusion, gray matter, white matter, and cerebrospinal fluid volumes using the statistical parametric mapping software package (SPM, University College London, UK) [33] and tools written in IDL. ECG, end tidal O2, CO2 and blood pressure were simultaneously acquired. An anatomical template (Laboratory of Neuro Imaging, University of California, Los Angles, USA) was applied to measure gray matter (GM), white matter (WM) and intracranial volume (ICV). Vessel diameters were calculated from 3D MR angiography (time of flight, TOF) using the Medical Image Processing, Analysis, and Visualization (MIPAV) software from the Biomedical Imaging Research Services Section, NIH, Bethesda, MD, at 3 locations and averaged, see Fig 1. Based on image resolution, the accuracy of the resulting MCA diameters is conservatively estimated at ±0.4 mm.


Transcranial Doppler-Based Surrogates for Cerebral Blood Flow: A Statistical Study
Left: time-of-flight MRA 3-D reconstruction; right: single-slice transverse view; bottom: zoom on the locations of three MCA radius estimates.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5120791&req=5

pone.0165536.g001: Left: time-of-flight MRA 3-D reconstruction; right: single-slice transverse view; bottom: zoom on the locations of three MCA radius estimates.
Mentions: High resolution anatomical images were acquired through 3D magnetization prepared rapid gradient echo (MP-RAGE) and fluid attenuation inversion recovery (FLAIR). Perfusion images were averaged during each condition (6 minutes baseline normocapnia) to improve the signal-to-noise ratio. Perfusion and anatomical MR images (MP-RAGE and FLAIR) was co-registered to a standard template of regional vascular territories and segmented to calculate regional perfusion, gray matter, white matter, and cerebrospinal fluid volumes using the statistical parametric mapping software package (SPM, University College London, UK) [33] and tools written in IDL. ECG, end tidal O2, CO2 and blood pressure were simultaneously acquired. An anatomical template (Laboratory of Neuro Imaging, University of California, Los Angles, USA) was applied to measure gray matter (GM), white matter (WM) and intracranial volume (ICV). Vessel diameters were calculated from 3D MR angiography (time of flight, TOF) using the Medical Image Processing, Analysis, and Visualization (MIPAV) software from the Biomedical Imaging Research Services Section, NIH, Bethesda, MD, at 3 locations and averaged, see Fig 1. Based on image resolution, the accuracy of the resulting MCA diameters is conservatively estimated at ±0.4 mm.

View Article: PubMed Central - PubMed

ABSTRACT

It is commonly assumed that perfusion in a given cerebral territory can be inferred from Blood Flow Velocity (BFV) measurements in the corresponding stem artery. In order to test this hypothesis, we construct a cerebral blood flow (CBF) estimator based on transcranial Doppler (TCD) blood flow velocity and ten other easily available patient characteristics and clinical parameters. A total of 261 measurements were collected from 88 older patients. The estimator is based on local regression (Random Forest). Its performance is analyzed against baseline CBF from 3-D pseudocontinuous arterial spin labeling (pCASL) magnetic resonance imaging (MRI). Patient specific CBF predictions are of poor quality (r = 0.41 and p-value = 4.5 × 10−12); the hypothesis is thus not clearly supported by evidence.

No MeSH data available.