Limits...
Cerebral blood flow measurement using fMRI and PET: a cross-validation study.

Chen JJ, Wieckowska M, Meyer E, Pike GB - Int J Biomed Imaging (2008)

Bottom Line: The CBF changes were compared using 3 types of region-of-interest (ROI) masks.FAIR measurements of CBF changes were found to be slightly lower than those measured with PET (average DeltaCBF of 21.5 +/- 8.2% for FAIR versus 28.2 +/- 12.8% for PET at maximum stimulation intensity).Finally, a t-test comparison of the slopes of the linear fits of PET versus ASL DeltaCBF for all 3 ROI types indicated no significant difference from unity (P > .05).

View Article: PubMed Central - PubMed

Affiliation: McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, PQ, Canada H3A 2B4. jean.chen@mail.mcgill.ca

ABSTRACT
An important aspect of functional magnetic resonance imaging (fMRI) is the study of brain hemodynamics, and MR arterial spin labeling (ASL) perfusion imaging has gained wide acceptance as a robust and noninvasive technique. However, the cerebral blood flow (CBF) measurements obtained with ASL fMRI have not been fully validated, particularly during global CBF modulations. We present a comparison of cerebral blood flow changes (DeltaCBF) measured using a flow-sensitive alternating inversion recovery (FAIR) ASL perfusion method to those obtained using H(2) (15)O PET, which is the current gold standard for in vivo imaging of CBF. To study regional and global CBF changes, a group of 10 healthy volunteers were imaged under identical experimental conditions during presentation of 5 levels of visual stimulation and one level of hypercapnia. The CBF changes were compared using 3 types of region-of-interest (ROI) masks. FAIR measurements of CBF changes were found to be slightly lower than those measured with PET (average DeltaCBF of 21.5 +/- 8.2% for FAIR versus 28.2 +/- 12.8% for PET at maximum stimulation intensity). Nonetheless, there was a strong correlation between measurements of the two modalities. Finally, a t-test comparison of the slopes of the linear fits of PET versus ASL DeltaCBF for all 3 ROI types indicated no significant difference from unity (P > .05).

No MeSH data available.


Related in: MedlinePlus

(a)The PET experimental protocol consisted of 6 randomly presented sessions(baseline, hypercapnia, and 4 levels of visual stimulation). A tracer bolusinjection was given at the start of each block. (b) Each run has a 3-minuteacquisition period divided in 12 5-second, 6 10-second, and 3 20-second frames,followed by 15 minutes of rest. (c) A volume of activity distribution wasacquired during each frame. (d) This series of distribution images and theblood activity curve were fit into a kinetic model, resulting in a CBF map.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2553188&req=5

fig2: (a)The PET experimental protocol consisted of 6 randomly presented sessions(baseline, hypercapnia, and 4 levels of visual stimulation). A tracer bolusinjection was given at the start of each block. (b) Each run has a 3-minuteacquisition period divided in 12 5-second, 6 10-second, and 3 20-second frames,followed by 15 minutes of rest. (c) A volume of activity distribution wasacquired during each frame. (d) This series of distribution images and theblood activity curve were fit into a kinetic model, resulting in a CBF map.

Mentions: Thegraded visual stimulation and hypercapnia schemes were matched to thosepreviously employed in calibrated fMRI studies of flow-metabolism coupling [3]. In addition to the uniformgrey-field reference condition, the subjects were presented with 4 gradedlevels of visual stimulation, ranging from 25% to 100% intensity, whileinhaling atmospheric composition medical air supplied at 16 L/min. Furthermore,mild hypercapnia (induced using air mixture of 5:21:74% CO2:O2:N2)was used to study global CBF changes. Both PET and ASL scans included 6sessions of 3 minutes, each consisting of one visual-respiratory conditionplayed out continuously. Each stimulation session was preceded and followed bya baseline condition (Figures 1 and 2) of 1 and 2 minutes, respectively.


Cerebral blood flow measurement using fMRI and PET: a cross-validation study.

Chen JJ, Wieckowska M, Meyer E, Pike GB - Int J Biomed Imaging (2008)

(a)The PET experimental protocol consisted of 6 randomly presented sessions(baseline, hypercapnia, and 4 levels of visual stimulation). A tracer bolusinjection was given at the start of each block. (b) Each run has a 3-minuteacquisition period divided in 12 5-second, 6 10-second, and 3 20-second frames,followed by 15 minutes of rest. (c) A volume of activity distribution wasacquired during each frame. (d) This series of distribution images and theblood activity curve were fit into a kinetic model, resulting in a CBF map.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2553188&req=5

fig2: (a)The PET experimental protocol consisted of 6 randomly presented sessions(baseline, hypercapnia, and 4 levels of visual stimulation). A tracer bolusinjection was given at the start of each block. (b) Each run has a 3-minuteacquisition period divided in 12 5-second, 6 10-second, and 3 20-second frames,followed by 15 minutes of rest. (c) A volume of activity distribution wasacquired during each frame. (d) This series of distribution images and theblood activity curve were fit into a kinetic model, resulting in a CBF map.
Mentions: Thegraded visual stimulation and hypercapnia schemes were matched to thosepreviously employed in calibrated fMRI studies of flow-metabolism coupling [3]. In addition to the uniformgrey-field reference condition, the subjects were presented with 4 gradedlevels of visual stimulation, ranging from 25% to 100% intensity, whileinhaling atmospheric composition medical air supplied at 16 L/min. Furthermore,mild hypercapnia (induced using air mixture of 5:21:74% CO2:O2:N2)was used to study global CBF changes. Both PET and ASL scans included 6sessions of 3 minutes, each consisting of one visual-respiratory conditionplayed out continuously. Each stimulation session was preceded and followed bya baseline condition (Figures 1 and 2) of 1 and 2 minutes, respectively.

Bottom Line: The CBF changes were compared using 3 types of region-of-interest (ROI) masks.FAIR measurements of CBF changes were found to be slightly lower than those measured with PET (average DeltaCBF of 21.5 +/- 8.2% for FAIR versus 28.2 +/- 12.8% for PET at maximum stimulation intensity).Finally, a t-test comparison of the slopes of the linear fits of PET versus ASL DeltaCBF for all 3 ROI types indicated no significant difference from unity (P > .05).

View Article: PubMed Central - PubMed

Affiliation: McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, PQ, Canada H3A 2B4. jean.chen@mail.mcgill.ca

ABSTRACT
An important aspect of functional magnetic resonance imaging (fMRI) is the study of brain hemodynamics, and MR arterial spin labeling (ASL) perfusion imaging has gained wide acceptance as a robust and noninvasive technique. However, the cerebral blood flow (CBF) measurements obtained with ASL fMRI have not been fully validated, particularly during global CBF modulations. We present a comparison of cerebral blood flow changes (DeltaCBF) measured using a flow-sensitive alternating inversion recovery (FAIR) ASL perfusion method to those obtained using H(2) (15)O PET, which is the current gold standard for in vivo imaging of CBF. To study regional and global CBF changes, a group of 10 healthy volunteers were imaged under identical experimental conditions during presentation of 5 levels of visual stimulation and one level of hypercapnia. The CBF changes were compared using 3 types of region-of-interest (ROI) masks. FAIR measurements of CBF changes were found to be slightly lower than those measured with PET (average DeltaCBF of 21.5 +/- 8.2% for FAIR versus 28.2 +/- 12.8% for PET at maximum stimulation intensity). Nonetheless, there was a strong correlation between measurements of the two modalities. Finally, a t-test comparison of the slopes of the linear fits of PET versus ASL DeltaCBF for all 3 ROI types indicated no significant difference from unity (P > .05).

No MeSH data available.


Related in: MedlinePlus