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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.

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Related in: MedlinePlus

Timeline of the simultaneous measurement of [15O]water PET and ASL in a 3T hybrid MR-PET scanner. ASL takes 7 minutes and PET takes 3 minutes. After a bolus injection of 555 MBq [15O]water PET listmode data were recorded for 3 minutes. ASL, arterial spin labeling; MR, magnetic resonance; PET, positron emission tomography.
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fig1: Timeline of the simultaneous measurement of [15O]water PET and ASL in a 3T hybrid MR-PET scanner. ASL takes 7 minutes and PET takes 3 minutes. After a bolus injection of 555 MBq [15O]water PET listmode data were recorded for 3 minutes. ASL, arterial spin labeling; MR, magnetic resonance; PET, positron emission tomography.

Mentions: Immediately after the initiation of the pCASL sequence, a physician entered the scanner room through an RF lock system to administer the [15O]water injection. After 2 minutes of pCASL acquisition, 555 MBq [15O]water was intravenously injected as a short bolus and the PET listmode acquisition was started for 3 minutes (Figure 1). Approximately 60 seconds before the radiotracer injection, the measurement of arterial whole blood radioactivity was started and continued for ∼4 minutes using a continuous blood sampler (Swisstrace, Zürich, Switzerland). This sampler consists of an MR-compatible coincidence detector block with two lutetium–yttrium oxyorthosilicate crystals crystals and is shielded by tungsten. The outer dimensions of the detector block are 80 × 62 × 56 mm3. The light pulses of the crystals are transferred via two flexible light guides of 10 m length each outside the scanner room to photomultipliers in the readout device where the coincidence detection and the data storage take place. The withdrawal rate of the MR-compatible pump was 500 mL/hour. The length of the catheter tube with an inner diameter of 1 mm was ∼30 cm from the radial artery to the detector block dependent on the arm's length of the subject. The radiation dose caused by one injection of 555 MBq [15O]water is 0.63 mSv.


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)

Timeline of the simultaneous measurement of [15O]water PET and ASL in a 3T hybrid MR-PET scanner. ASL takes 7 minutes and PET takes 3 minutes. After a bolus injection of 555 MBq [15O]water PET listmode data were recorded for 3 minutes. ASL, arterial spin labeling; MR, magnetic resonance; PET, positron emission tomography.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig1: Timeline of the simultaneous measurement of [15O]water PET and ASL in a 3T hybrid MR-PET scanner. ASL takes 7 minutes and PET takes 3 minutes. After a bolus injection of 555 MBq [15O]water PET listmode data were recorded for 3 minutes. ASL, arterial spin labeling; MR, magnetic resonance; PET, positron emission tomography.
Mentions: Immediately after the initiation of the pCASL sequence, a physician entered the scanner room through an RF lock system to administer the [15O]water injection. After 2 minutes of pCASL acquisition, 555 MBq [15O]water was intravenously injected as a short bolus and the PET listmode acquisition was started for 3 minutes (Figure 1). Approximately 60 seconds before the radiotracer injection, the measurement of arterial whole blood radioactivity was started and continued for ∼4 minutes using a continuous blood sampler (Swisstrace, Zürich, Switzerland). This sampler consists of an MR-compatible coincidence detector block with two lutetium–yttrium oxyorthosilicate crystals crystals and is shielded by tungsten. The outer dimensions of the detector block are 80 × 62 × 56 mm3. The light pulses of the crystals are transferred via two flexible light guides of 10 m length each outside the scanner room to photomultipliers in the readout device where the coincidence detection and the data storage take place. The withdrawal rate of the MR-compatible pump was 500 mL/hour. The length of the catheter tube with an inner diameter of 1 mm was ∼30 cm from the radial artery to the detector block dependent on the arm's length of the subject. The radiation dose caused by one injection of 555 MBq [15O]water is 0.63 mSv.

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