Limits...
Comparison of cerebral blood flow acquired by simultaneous [15O]water positron emission tomography and arterial spin labeling magnetic resonance imaging.

Zhang K, Herzog H, Mauler J, Filss C, Okell TW, Kops ER, Tellmann L, Fischer T, Brocke B, Sturm W, Coenen HH, Shah NJ - J. Cereb. Blood Flow Metab. (2014)

Bottom Line: This study presents results of CBF measurements recorded simultaneously with [(15)O]water and ASL.A statistically significant (P<0.05) correlation was observed between the two modalities; the whole-brain CBF values determined with PET and pCASL were 43.3±6.1 mL and 51.9±7.1 mL per 100 g per minute, respectively.Regional and individual differences were found despite the overall similarity between ASL and PET, requiring further detailed investigations.

View Article: PubMed Central - PubMed

Affiliation: Institute of Neuroscience and Medicine-4: Medical Imaging Physics, Forschungszentrum Jülich, Jülich, Germany.

ABSTRACT
Until recently, no direct comparison between [(15)O]water positron emission tomography (PET) and arterial spin labeling (ASL) for measuring cerebral blood flow (CBF) was possible. With the introduction of integrated, hybrid magnetic resonance (MR)-PET scanners, such a comparison becomes feasible. This study presents results of CBF measurements recorded simultaneously with [(15)O]water and ASL. A 3T MR-BrainPET scanner was used for the simultaneous acquisition of pseudo-continuous ASL (pCASL) magnetic resonance imaging (MRI) and [(15)O]water PET. Quantitative CBF values were compared in 10 young healthy male volunteers at baseline conditions. A statistically significant (P<0.05) correlation was observed between the two modalities; the whole-brain CBF values determined with PET and pCASL were 43.3±6.1 mL and 51.9±7.1 mL per 100 g per minute, respectively. The gray/white matter (GM/WM) ratio of CBF was 3.0 for PET and 3.4 for pCASL. A paired t-test revealed differences in regional CBF between ASL and PET with higher ASL-CBF than PET-CBF values in cortical areas. Using an integrated, hybrid MR-PET a direct simultaneous comparison between ASL and [(15)O]water PET became possible for the first time so that temporal, physiologic, and functional variations were avoided. Regional and individual differences were found despite the overall similarity between ASL and PET, requiring further detailed investigations.

Show MeSH

Related in: MedlinePlus

Comparative images of PET-CBF and ASL-CBF at the level of the basal ganglia in the individual subjects S1 to S10 (A). All images are normalized to the MNI space. A VOI (in pink) comprising the entire brain was defined for the calculation of the whole-brain CBF. Scatter plots of VOI averages of CBF in the whole brain (B), white matter (C), and gray matter (D) indicate positive correlations between PET-CBF and ASL-CBF. R is the Pearson correlation coefficient. ASL, arterial spin labeling; CBF, cerebral blood flow; MNI, Montreal Neurological Institute; PET, positron emission tomography; VOI, volume of interest.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4126098&req=5

fig4: Comparative images of PET-CBF and ASL-CBF at the level of the basal ganglia in the individual subjects S1 to S10 (A). All images are normalized to the MNI space. A VOI (in pink) comprising the entire brain was defined for the calculation of the whole-brain CBF. Scatter plots of VOI averages of CBF in the whole brain (B), white matter (C), and gray matter (D) indicate positive correlations between PET-CBF and ASL-CBF. R is the Pearson correlation coefficient. ASL, arterial spin labeling; CBF, cerebral blood flow; MNI, Montreal Neurological Institute; PET, positron emission tomography; VOI, volume of interest.

Mentions: The individual CBF data of all 10 subjects, S1 to S10, measured in the VOIs of whole brain, GM, and WM are presented in Figure 4. A comparison of individual CBF images at the level of the basal ganglia obtained with ASL and PET in each of the 10 subjects, S1 to S10, is provided in Figure 4A. There is good overall agreement of the individual images acquired with the two modalities; that is, low ASL-CBF images match with low PET-CBF images and vice versa. However, a closer examination reveals local differences between the two methods. The individual, whole-brain CBF data obtained with ASL and [15O]water PET, respectively, in the 10 subjects are compared in Figure 4B. The scatter plot shows a high correlation between ASL and PET with a Pearson correlation coefficient of 0.81 (P<0.005) and Spearman correlation coefficient of 0.65 (P<0.05). The corresponding comparisons of GM and WM CBF data are shown in Figures 4D and C, respectively. Here again positive correlations were observed between ASL and PET across the 10 subjects with Pearson correlation coefficients of 0.80 (P<0.01) and 0.94 (P<0.001), respectively, and Spearman correlation coefficients of 0.64 (P<0.05) and 0.90 (P<0.001), respectively. Furthermore, Bland–Altman plots of the CBF data resulting from ASL and [15O]water PET show small ranges of differences between the two modalities (Figure 5). For whole brain, GM, and WM the difference in CBF between ASL and PET is within the two standard deviation lines (0.95 confidence interval).


Comparison of cerebral blood flow acquired by simultaneous [15O]water positron emission tomography and arterial spin labeling magnetic resonance imaging.

Zhang K, Herzog H, Mauler J, Filss C, Okell TW, Kops ER, Tellmann L, Fischer T, Brocke B, Sturm W, Coenen HH, Shah NJ - J. Cereb. Blood Flow Metab. (2014)

Comparative images of PET-CBF and ASL-CBF at the level of the basal ganglia in the individual subjects S1 to S10 (A). All images are normalized to the MNI space. A VOI (in pink) comprising the entire brain was defined for the calculation of the whole-brain CBF. Scatter plots of VOI averages of CBF in the whole brain (B), white matter (C), and gray matter (D) indicate positive correlations between PET-CBF and ASL-CBF. R is the Pearson correlation coefficient. ASL, arterial spin labeling; CBF, cerebral blood flow; MNI, Montreal Neurological Institute; PET, positron emission tomography; VOI, volume of interest.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126098&req=5

fig4: Comparative images of PET-CBF and ASL-CBF at the level of the basal ganglia in the individual subjects S1 to S10 (A). All images are normalized to the MNI space. A VOI (in pink) comprising the entire brain was defined for the calculation of the whole-brain CBF. Scatter plots of VOI averages of CBF in the whole brain (B), white matter (C), and gray matter (D) indicate positive correlations between PET-CBF and ASL-CBF. R is the Pearson correlation coefficient. ASL, arterial spin labeling; CBF, cerebral blood flow; MNI, Montreal Neurological Institute; PET, positron emission tomography; VOI, volume of interest.
Mentions: The individual CBF data of all 10 subjects, S1 to S10, measured in the VOIs of whole brain, GM, and WM are presented in Figure 4. A comparison of individual CBF images at the level of the basal ganglia obtained with ASL and PET in each of the 10 subjects, S1 to S10, is provided in Figure 4A. There is good overall agreement of the individual images acquired with the two modalities; that is, low ASL-CBF images match with low PET-CBF images and vice versa. However, a closer examination reveals local differences between the two methods. The individual, whole-brain CBF data obtained with ASL and [15O]water PET, respectively, in the 10 subjects are compared in Figure 4B. The scatter plot shows a high correlation between ASL and PET with a Pearson correlation coefficient of 0.81 (P<0.005) and Spearman correlation coefficient of 0.65 (P<0.05). The corresponding comparisons of GM and WM CBF data are shown in Figures 4D and C, respectively. Here again positive correlations were observed between ASL and PET across the 10 subjects with Pearson correlation coefficients of 0.80 (P<0.01) and 0.94 (P<0.001), respectively, and Spearman correlation coefficients of 0.64 (P<0.05) and 0.90 (P<0.001), respectively. Furthermore, Bland–Altman plots of the CBF data resulting from ASL and [15O]water PET show small ranges of differences between the two modalities (Figure 5). For whole brain, GM, and WM the difference in CBF between ASL and PET is within the two standard deviation lines (0.95 confidence interval).

Bottom Line: This study presents results of CBF measurements recorded simultaneously with [(15)O]water and ASL.A statistically significant (P<0.05) correlation was observed between the two modalities; the whole-brain CBF values determined with PET and pCASL were 43.3±6.1 mL and 51.9±7.1 mL per 100 g per minute, respectively.Regional and individual differences were found despite the overall similarity between ASL and PET, requiring further detailed investigations.

View Article: PubMed Central - PubMed

Affiliation: Institute of Neuroscience and Medicine-4: Medical Imaging Physics, Forschungszentrum Jülich, Jülich, Germany.

ABSTRACT
Until recently, no direct comparison between [(15)O]water positron emission tomography (PET) and arterial spin labeling (ASL) for measuring cerebral blood flow (CBF) was possible. With the introduction of integrated, hybrid magnetic resonance (MR)-PET scanners, such a comparison becomes feasible. This study presents results of CBF measurements recorded simultaneously with [(15)O]water and ASL. A 3T MR-BrainPET scanner was used for the simultaneous acquisition of pseudo-continuous ASL (pCASL) magnetic resonance imaging (MRI) and [(15)O]water PET. Quantitative CBF values were compared in 10 young healthy male volunteers at baseline conditions. A statistically significant (P<0.05) correlation was observed between the two modalities; the whole-brain CBF values determined with PET and pCASL were 43.3±6.1 mL and 51.9±7.1 mL per 100 g per minute, respectively. The gray/white matter (GM/WM) ratio of CBF was 3.0 for PET and 3.4 for pCASL. A paired t-test revealed differences in regional CBF between ASL and PET with higher ASL-CBF than PET-CBF values in cortical areas. Using an integrated, hybrid MR-PET a direct simultaneous comparison between ASL and [(15)O]water PET became possible for the first time so that temporal, physiologic, and functional variations were avoided. Regional and individual differences were found despite the overall similarity between ASL and PET, requiring further detailed investigations.

Show MeSH
Related in: MedlinePlus