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Goodnough CL, Gao Y, Li X, Qutaish MQ, Goodnough LH, Molter J, Wilson D, Flask CA, Yu X. Lack of dystrophin results in abnormal cerebral diffusion and perfusion in vivo. Neuroimage 2014; 102 Pt 2:809-16. [PMID: 25213753 PMCID: PMC4320943 DOI: 10.1016/j.neuroimage.2014.08.053] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 08/25/2014] [Accepted: 08/29/2014] [Indexed: 01/08/2023] Open
Abstract
Dystrophin, the main component of the dystrophin–glycoprotein complex, plays an important role in maintaining the structural integrity of cells. It is also involved in the formation of the blood–brain barrier (BBB). To elucidate the impact of dystrophin disruption in vivo, we characterized changes in cerebral perfusion and diffusion in dystrophin-deficient mice (mdx) by magnetic resonance imaging (MRI). Arterial spin labeling (ASL) and diffusion-weighted MRI (DWI) studies were performed on 2-month-old and 10-month-old mdx mice and their age-matched wild-type controls (WT). The imaging results were correlated with Evan's blue extravasation and vascular density studies. The results show that dystrophin disruption significantly decreased the mean cerebral diffusivity in both 2-month-old (7.38± 0.30 × 10−4mm2/s) and 10-month-old (6.93 ± 0.53 × 10−4 mm2/s) mdx mice as compared to WT (8.49±0.24×10−4, 8.24±0.25× 10−4mm2/s, respectively). There was also an 18% decrease in cerebral perfusion in 10-month-old mdx mice as compared to WT, which was associated with enhanced arteriogenesis. The reduction in water diffusivity in mdx mice is likely due to an increase in cerebral edema or the existence of large molecules in the extracellular space from a leaky BBB. The observation of decreased perfusion in the setting of enhanced arteriogenesis may be caused by an increase of intracranial pressure from cerebral edema. This study demonstrates the defects in water handling at the BBB and consequently, abnormal perfusion associated with the absence of dystrophin.
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Affiliation(s)
- Candida L Goodnough
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ying Gao
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xin Li
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Mohammed Q Qutaish
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - L Henry Goodnough
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Joseph Molter
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - David Wilson
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Chris A Flask
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xin Yu
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Radiology, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
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202
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Boudes E, Gilbert G, Leppert IR, Tan X, Pike GB, Saint-Martin C, Wintermark P. Measurement of brain perfusion in newborns: pulsed arterial spin labeling (PASL) versus pseudo-continuous arterial spin labeling (pCASL). NEUROIMAGE-CLINICAL 2014; 6:126-33. [PMID: 25379424 PMCID: PMC4215516 DOI: 10.1016/j.nicl.2014.08.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 07/31/2014] [Accepted: 08/16/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND Arterial spin labeling (ASL) perfusion-weighted imaging (PWI) by magnetic resonance imaging (MRI) has been shown to be useful for identifying asphyxiated newborns at risk of developing brain injury, whether or not therapeutic hypothermia was administered. However, this technique has been only rarely used in newborns until now, because of the challenges to obtain sufficient signal-to-noise ratio (SNR) and spatial resolution in newborns. OBJECTIVE To compare two methods of ASL-PWI (i.e., single inversion-time pulsed arterial spin labeling [single TI PASL], and pseudo-continuous arterial spin labeling [pCASL]) to assess brain perfusion in asphyxiated newborns treated with therapeutic hypothermia and in healthy newborns. DESIGN/METHODS We conducted a prospective cohort study of term asphyxiated newborns meeting the criteria for therapeutic hypothermia; four additional healthy term newborns were also included as controls. Each of the enrolled newborns was scanned at least once during the first month of life. Each MRI scan included conventional anatomical imaging, as well as PASL and pCASL PWI-MRI. Control and labeled images were registered separately to reduce the effect of motion artifacts. For each scan, the axial slice at the level of the basal ganglia was used for comparisons. Each scan was scored for its image quality. Quantification of whole-slice cerebral blood flow (CBF) was done afterwards using previously described formulas. RESULTS A total number of 61 concomitant PASL and pCASL scans were obtained in nineteen asphyxiated newborns treated with therapeutic hypothermia and four healthy newborns. After discarding the scans with very poor image quality, 75% (46/61) remained for comparison between the two ASL methods. pCASL images presented a significantly superior image quality score compared to PASL images (p < 0.0001). Strong correlation was found between the CBF measured by PASL and pCASL (r = 0.61, p < 0.0001). CONCLUSION This study demonstrates that both ASL methods are feasible to assess brain perfusion in healthy and sick newborns. However, pCASL might be a better choice over PASL in newborns, as pCASL perfusion maps had a superior image quality that allowed a more detailed identification of the different brain structures.
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Affiliation(s)
- Elodie Boudes
- Division of Newborn Medicine, Department of Pediatrics, Montreal Children's Hospital, McGill University, Montreal, Canada
| | | | | | - Xianming Tan
- Center for Innovative Medicine, Research Institute, McGill University Health Centre, Montreal, Canada
| | - G Bruce Pike
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada ; Department of Radiology, University of Calgary, Calgary, Canada
| | - Christine Saint-Martin
- Department of Radiology, Montreal Children's Hospital, McGill University, Montreal, Canada
| | - Pia Wintermark
- Division of Newborn Medicine, Department of Pediatrics, Montreal Children's Hospital, McGill University, Montreal, Canada
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203
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Varela M, Petersen ET, Golay X, Hajnal JV. Cerebral blood flow measurements in infants using look-locker arterial spin labeling. J Magn Reson Imaging 2014; 41:1591-600. [DOI: 10.1002/jmri.24716] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 07/12/2014] [Accepted: 07/15/2014] [Indexed: 11/09/2022] Open
Affiliation(s)
- Marta Varela
- Department of Biomedical Engineering; Division of Imaging Sciences; King's College London; London UK
- Imaging Sciences Department; MRC Clinical Sciences Centre, Imperial College London; London UK
| | - Esben T. Petersen
- Department of Radiology; University Medical Center; Utrecht The Netherlands
| | - Xavier Golay
- UCL Institute of Neurology; University College London; London UK
| | - Joseph V. Hajnal
- Department of Biomedical Engineering; Division of Imaging Sciences; King's College London; London UK
- Imaging Sciences Department; MRC Clinical Sciences Centre, Imperial College London; London UK
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204
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Intravoxel incoherent motion (IVIM) imaging at different magnetic field strengths: what is feasible? Magn Reson Imaging 2014; 32:1247-58. [PMID: 25109587 DOI: 10.1016/j.mri.2014.07.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 05/28/2014] [Accepted: 07/25/2014] [Indexed: 11/22/2022]
Abstract
BACKGROUND Due to limited SNR the cerebral applications of the intravoxel incoherent motion (IVIM) concept have been sparse. MRI hardware developments have resulted in improved SNR and this may justify a reassessment of IVIM imaging for non-invasive quantification of the cerebral blood volume (CBV) as a first step toward determining the optimal field strength. PURPOSE To investigate intravoxel incoherent motion imaging for its potential to assess cerebral blood volume (CBV) at three different MRI field strengths. MATERIALS AND METHODS Four volunteers were scanned twice at 1.5 T, 3 T as well as 7 T. By correcting for field-strength-dependent effects of relaxation, estimates of corrected CBV (cCBV) were obtained in deep gray matter (DGM), frontal gray matter (FGM) and frontal white matter (FWM), using Bayesian analysis. In addition, simulations were performed to facilitate the interpretation of experimental data. RESULTS In DGM, FGM and FWM we obtained cCBV estimates of 2.2 ml/100 ml, 2.7 ml/100 ml, 1.4 ml/100 ml at 1.5 T; 3.7 ml/100 ml, 5.0 ml/100 ml, 3.2 ml/100 ml at 3 T and 15.5 ml/100 ml, 20.3 ml/100 ml, 7.0 ml/100 ml at 7 T. CONCLUSION Quantitative cCBV values obtained at 1.5 T and 3 T corresponded better to physiological reference values, while 7 T showed the largest deviation from expected values. Simulations of synthetic tissue voxels indicated that the discrepancy at 7 T can partly be explained by SNR issues. Results were generally more repeatable at 7 T (intraclass correlation coefficient, ICC=0.84) than at 1.5 T (ICC=0.68) and 3 T (ICC=0.46).
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205
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Mutsaerts HJMM, Steketee RME, Heijtel DFR, Kuijer JPA, van Osch MJP, Majoie CBLM, Smits M, Nederveen AJ. Inter-vendor reproducibility of pseudo-continuous arterial spin labeling at 3 Tesla. PLoS One 2014; 9:e104108. [PMID: 25090654 PMCID: PMC4121318 DOI: 10.1371/journal.pone.0104108] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 07/08/2014] [Indexed: 11/19/2022] Open
Abstract
PURPOSE Prior to the implementation of arterial spin labeling (ASL) in clinical multi-center studies, it is important to establish its status quo inter-vendor reproducibility. This study evaluates and compares the intra- and inter-vendor reproducibility of pseudo-continuous ASL (pCASL) as clinically implemented by GE and Philips. MATERIAL AND METHODS 22 healthy volunteers were scanned twice on both a 3T GE and a 3T Philips scanner. The main difference in implementation between the vendors was the readout module: spiral 3D fast spin echo vs. 2D gradient-echo echo-planar imaging respectively. Mean and variation of cerebral blood flow (CBF) were compared for the total gray matter (GM) and white matter (WM), and on a voxel-level. RESULTS Whereas the mean GM CBF of both vendors was almost equal (p = 1.0), the mean WM CBF was significantly different (p<0.01). The inter-vendor GM variation did not differ from the intra-vendor GM variation (p = 0.3 and p = 0.5 for GE and Philips respectively). Spatial inter-vendor CBF and variation differences were observed in several GM regions and in the WM. CONCLUSION These results show that total GM CBF-values can be exchanged between vendors. For the inter-vendor comparison of GM regions or WM, these results encourage further standardization of ASL implementation among vendors.
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Affiliation(s)
| | - Rebecca M. E. Steketee
- Department of Radiology, Erasmus MC University Medical Center Rotterdam, Rotterdam, The Netherlands
| | | | - Joost P. A. Kuijer
- Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands
| | - Matthias J. P. van Osch
- C. J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Marion Smits
- Department of Radiology, Erasmus MC University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Aart J. Nederveen
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
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206
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Gao Y, Goodnough CL, Erokwu BO, Farr GW, Darrah R, Lu L, Dell KM, Yu X, Flask CA. Arterial spin labeling-fast imaging with steady-state free precession (ASL-FISP): a rapid and quantitative perfusion technique for high-field MRI. NMR IN BIOMEDICINE 2014; 27:996-1004. [PMID: 24891124 PMCID: PMC4110188 DOI: 10.1002/nbm.3143] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 04/28/2014] [Accepted: 04/30/2014] [Indexed: 05/03/2023]
Abstract
Arterial spin labeling (ASL) is a valuable non-contrast perfusion MRI technique with numerous clinical applications. Many previous ASL MRI studies have utilized either echo-planar imaging (EPI) or true fast imaging with steady-state free precession (true FISP) readouts, which are prone to off-resonance artifacts on high-field MRI scanners. We have developed a rapid ASL-FISP MRI acquisition for high-field preclinical MRI scanners providing perfusion-weighted images with little or no artifacts in less than 2 s. In this initial implementation, a flow-sensitive alternating inversion recovery (FAIR) ASL preparation was combined with a rapid, centrically encoded FISP readout. Validation studies on healthy C57/BL6 mice provided consistent estimation of in vivo mouse brain perfusion at 7 and 9.4 T (249 ± 38 and 241 ± 17 mL/min/100 g, respectively). The utility of this method was further demonstrated in the detection of significant perfusion deficits in a C57/BL6 mouse model of ischemic stroke. Reasonable kidney perfusion estimates were also obtained for a healthy C57/BL6 mouse exhibiting differential perfusion in the renal cortex and medulla. Overall, the ASL-FISP technique provides a rapid and quantitative in vivo assessment of tissue perfusion for high-field MRI scanners with minimal image artifacts.
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Affiliation(s)
- Ying Gao
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Candida L. Goodnough
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
| | | | - George W. Farr
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
- Aeromics, LLC, Cleveland, OH 44106
| | - Rebecca Darrah
- Frances Payne Bolton School of Nursing, Case Western Reserve University, Cleveland, OH 44106
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106
| | - Lan Lu
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106
- Department of Urology, Case Western Reserve University, Cleveland, OH 44106
| | - Katherine M. Dell
- CWRU Center for the Study of Kidney Disease and Biology, MetroHealth Campus, Case Western Reserve University, Cleveland, OH 44109
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106
| | - Xin Yu
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
| | - Chris A. Flask
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106
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207
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Dynamic perfusion and diffusion MRI of cortical spreading depolarization in photothrombotic ischemia. Neurobiol Dis 2014; 71:131-9. [PMID: 25066776 DOI: 10.1016/j.nbd.2014.07.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/15/2014] [Accepted: 07/16/2014] [Indexed: 11/21/2022] Open
Abstract
Cortical spreading depolarization (CSD) is known to exacerbate ischemic damage, as the number of CSDs correlates with the final infarct volumes and suppressing CSDs improves functional outcomes. To investigate the role of CSD in ischemic damage, we developed a novel rat model of photothrombotic ischemia using a miniature implantable optic fiber that allows lesion induction inside the magnetic resonance imaging (MRI) scanner. We were able to precisely control the location and the size of the ischemic lesion, and continuously monitor dynamic perfusion and diffusion MRI signal changes at high temporal resolution before, during and after the onset of focal ischemia. Our model showed that apparent diffusion coefficient (ADC) and cerebral blood flow (CBF) in the ischemic core dropped immediately after lesion onset by 20±6 and 41±23%, respectively, and continually declined over the next 5h. Meanwhile, CSDs were observed in all animals (n=36) and displayed either a transient decrease of ADC by 17±3% or an increase of CBF by 104±15%. All CSDs were initiated from the rim of the ischemic core, propagated outward, and confined to the ipsilesional cortex. Additionally, we demonstrated that by controlling the size of perfusion-diffusion mismatch (which approximates the penumbra) in our model, the number of CSDs correlated with the mismatch area rather than the final infarct volume. This study introduces a novel platform to study CSDs in real-time with high reproducibility using MRI.
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208
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Donahue MJ, Faraco CC, Strother MK, Chappell MA, Rane S, Dethrage LM, Hendrikse J, Siero JCW. Bolus arrival time and cerebral blood flow responses to hypercarbia. J Cereb Blood Flow Metab 2014; 34:1243-52. [PMID: 24780904 PMCID: PMC4083394 DOI: 10.1038/jcbfm.2014.81] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 04/07/2014] [Accepted: 04/09/2014] [Indexed: 11/09/2022]
Abstract
The purpose of this study was to evaluate how cerebral blood flow and bolus arrival time (BAT) measures derived from arterial spin labeling (ASL) MRI data change for different hypercarbic gas stimuli. Pseudocontinuous ASL (pCASL) was applied (3.0T; spatial resolution=4 × 4 × 7 mm(3); repetition time/echo time (TR/TE)=3,600/11 ms) sequentially in healthy volunteers (n=12; age=30±4 years) for separate experiments in which (i) normocarbic normoxia (i.e., room air), hypercarbic normoxia (i.e., 5% CO₂/21% O₂/74% N2), and hypercarbic hyperoxia (i.e., carbogen: 5% CO₂/95% O₂) gas was administered (12 L/minute). Cerebral blood flow and BAT changes were quantified using models that account for macrovascular signal and partial volume effects in all gray matter and regionally in cerebellar, temporal, occipital, frontal, and parietal lobes. Regional reductions in BAT of 4.6% to 7.7% and 3.3% to 6.6% were found in response to hypercarbic normoxia and hypercarbic hyperoxia, respectively. Cerebral blood flow increased by 8.2% to 27.8% and 3.5% to 19.8% for hypercarbic normoxia and hypercarbic hyperoxia, respectively. These findings indicate that changes in BAT values may bias functional ASL data and thus should be considered when choosing appropriate experimental parameters in calibrated functional magnetic resonance imaging or ASL cerebrovascular reactivity experiments that use hypercarbic gas stimuli.
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Affiliation(s)
- Manus J Donahue
- 1] Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, USA [2] Psychiatry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA [3] Neurology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA [4] Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA
| | - Carlos C Faraco
- Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Megan K Strother
- Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | | | - Swati Rane
- Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Lindsey M Dethrage
- Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Jeroen Hendrikse
- Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeroen C W Siero
- Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
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209
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Non-invasive MRI measurements of venous oxygenation, oxygen extraction fraction and oxygen consumption in neonates. Neuroimage 2014; 95:185-92. [DOI: 10.1016/j.neuroimage.2014.03.060] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 03/08/2014] [Accepted: 03/22/2014] [Indexed: 11/17/2022] Open
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210
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Gardener AG, Jezzard P. Investigating white matter perfusion using optimal sampling strategy arterial spin labeling at 7 Tesla. Magn Reson Med 2014; 73:2243-8. [PMID: 24954898 PMCID: PMC4657501 DOI: 10.1002/mrm.25333] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 06/02/2014] [Accepted: 06/03/2014] [Indexed: 01/05/2023]
Abstract
PURPOSE Cerebral blood flow (CBF) is an informative physiological marker for tissue health. Arterial spin labeling (ASL) is a noninvasive MRI method of measuring this parameter, but it has proven difficult to measure white matter (WM) CBF due to low intrinsic contrast-to-noise ratio compared with gray matter (GM). Here we combine ultra-high field and optimal sampling strategy (OSS) ASL to investigate WM CBF in reasonable scan times. METHODS A FAIR-based ASL sequence at 7T was combined with a real-time-feedback OSS technique, to iteratively improve post-label image acquisition times (TIs) on a tissue- and subject-specific basis to obtain WM CBF quantification. RESULTS It was found 77% of WM voxels gave a reasonable CBF fit. Averaged WM CBF for these voxels was found to be 16.3 ± 1.5 mL/100 g/min (discarding partial-volumed voxels). The generated TI schedule was also significantly different when altering the OSS weighted-tissue-mask, favoring longer TIs in WM. CONCLUSION WM CBF could be reasonably quantified in over 75% of identified voxels, from a total preparation and scan time of 15 min. OSS results suggest longer TIs should be used versus general GM ASL settings; this may become more important in WM disease studies.
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Affiliation(s)
- Alexander G Gardener
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Peter Jezzard
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
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211
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van der Meer JN, Heijtel DFR, van Hest G, Plattèl GJ, van Osch MJP, van Someren EJW, vanBavel ET, Nederveen AJ. Acoustic noise reduction in pseudo-continuous arterial spin labeling (pCASL). MAGMA (NEW YORK, N.Y.) 2014; 27:269-276. [PMID: 24061611 DOI: 10.1007/s10334-013-0406-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/31/2013] [Accepted: 09/02/2013] [Indexed: 06/02/2023]
Abstract
OBJECT While pseudo-continuous arterial spin labeling (pCASL) is a promising imaging technique to visualize cerebral blood flow, it is also (acoustically) very loud during labeling. In this paper, we reduced the labeling loudness on our scanner by increasing the interval between the RF pulses from the literature standard of 1.0 ms. We also propose recommendations to reduce the loudness on scanners of the same type at other sites. MATERIALS AND METHODS First, the sound pressure level (SPL) was both simulated and measured as a function of the labeling interval (1.0-1.8 ms) and longitudinal position in the scanner (-10 to +10 cm, relative to isocenter). Subsequently, we selected the labeling interval with the lowest overall SPL for the "SPL-optimized" pCASL sequence. Nine volunteers were scanned to compare raw signal intensity, temporal signal-to-noise ratio (tSNR) and labeling efficiency between the SPL-optimized and the standard PCASL sequence. RESULTS Sound pressure level measurements on our scanner showed that loudness was reduced by 6.5 dB at the approximate location of the ear by adjusting the labeling interval to 1.4 ms. Furthermore, image quality was not affected, since no significant differences in signal intensity, tSNR and labeling efficiency were observed. CONCLUSION By increasing the pCASL labeling interval, acoustic noise in the pCASL sequence was reduced with 6.5 dB, while image quality was preserved.
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Affiliation(s)
- Johan N van der Meer
- Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Institute of the Royal Academy of Arts and Sciences, Amsterdam, The Netherlands,
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212
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Tarumi T, Ayaz Khan M, Liu J, Tseng BY, Parker R, Riley J, Tinajero C, Zhang R, Zhang R. Cerebral hemodynamics in normal aging: central artery stiffness, wave reflection, and pressure pulsatility. J Cereb Blood Flow Metab 2014; 34:971-8. [PMID: 24643081 PMCID: PMC4050241 DOI: 10.1038/jcbfm.2014.44] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/17/2014] [Accepted: 02/14/2014] [Indexed: 11/09/2022]
Abstract
Blood ejected from the left ventricle perfuses the brain via central elastic arteries, which stiffen with advancing age and may elevate the risk of end-organ damage. The purpose of this study was to determine the impact of central arterial aging on cerebral hemodynamics. Eighty-three healthy participants aged 22 to 80 years underwent the measurements of cerebral blood flow (CBF) and CBF velocity (CBFV) using magnetic resonance imaging (MRI) and transcranial Doppler, respectively. The CBF pulsatility was determined by the relative amplitude of CBFV to the mean value (CBFV%). Central arterial stiffness (carotid-femoral pulse wave velocity), wave reflection (carotid augmentation index), and pressure were measured using applanation tonometry. Total volume of white-matter hyperintensity (WMH) was quantified from MR images. Total CBF decreased with age while systolic and pulsatile CBFV% increased and diastolic CBFV% decreased. Women showed greater total CBF and lower cerebrovascular resistance than men. Diastolic CBFV% was lower in women than in men. Age- and sex-related differences in CBF pulsatility were independently associated with carotid pulse pressure and arterial wave reflection. In older participants, higher pulsatility of CBF was associated with the greater total volume of WMH. These findings indicate that central arterial aging has an important role in age-related differences in cerebral hemodynamics.
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Affiliation(s)
- Takashi Tarumi
- 1] Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA [2] Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Muhammad Ayaz Khan
- 1] Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA [2] Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jie Liu
- 1] Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA [2] Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Benjamin Y Tseng
- 1] Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA [2] Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Rosemary Parker
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
| | - Jonathan Riley
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
| | - Cynthia Tinajero
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
| | - Rong Zhang
- 1] Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA [2] Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Rong Zhang
- 1] Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA [2] Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Liu P, Lu H, Filbey FM, Tamminga CA, Cao Y, Adinoff B. MRI assessment of cerebral oxygen metabolism in cocaine-addicted individuals: hypoactivity and dose dependence. NMR IN BIOMEDICINE 2014; 27:726-32. [PMID: 24757009 PMCID: PMC4084967 DOI: 10.1002/nbm.3114] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 02/16/2014] [Accepted: 03/13/2014] [Indexed: 05/26/2023]
Abstract
Long-term cocaine use is known to negatively impact neural and cerebrovascular systems. However, the use of imaging markers to separately assess these parameters remains challenging. The primary reason is that most functional imaging markers, such as cerebral blood flow, functional connectivity, and task-evoked functional MRI, are known to reflect a complex interplay between neural and vascular components, thus the interpretation of the results is not straightforward. The goal of the present study is to examine neural-activity-specific changes in cocaine addiction, using cerebral metabolic rate of oxygen (CMRO2) as a surrogate marker of aggregated neural activity. We applied a recently developed CMRO2 technique in 13 cocaine-addicted subjects and 13 age- and gender-matched control subjects, and examined the impact of long-term cocaine use on CMRO2. Our results showed that CMRO2 in cocaine-addicted subjects (152 ± 16 µmol/100 g/min) is significantly lower (p = 0.031) than that in controls (169 ± 20 µmol/100 g/min). Furthermore, the severity of this decreased metabolism is associated with lifetime cocaine use (p = 0.05). Additionally, the CMRO2 reduction was accompanied by a trend of decrease in cerebral blood flow (p = 0.058), but venous oxygenation was unaffected (p = 0.96), which suggested that the CMRO2 change may be attributed to a vascular deficiency in chronic cocaine users. To our knowledge, this is the first study to measure CMRO2 in cocaine-addicted individuals. Our findings suggest that CMRO2 may be a promising approach for assessing the long-term effects of cocaine use on the brain.
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Affiliation(s)
- Peiying Liu
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Hanzhang Lu
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | | | - Carol A. Tamminga
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Yan Cao
- Department of Mathematical Sciences, University of Texas at Dallas, Richardson, Texas 75080
| | - Bryon Adinoff
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390
- VA North Texas Health Care System, Dallas, Texas 75216
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214
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Age-related increase of resting metabolic rate in the human brain. Neuroimage 2014; 98:176-83. [PMID: 24814209 DOI: 10.1016/j.neuroimage.2014.04.078] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 04/11/2014] [Accepted: 04/28/2014] [Indexed: 11/21/2022] Open
Abstract
With age, many aspects of the brain structure undergo a pronounced decline, yet individuals generally function well until advanced old age. There appear to be several compensatory mechanisms in brain aging, but their precise nature is not well characterized. Here we provide evidence that the brain of older adults expends more energy when compared to younger adults, as manifested by an age-related increase (P=0.03) in cerebral metabolic rate of oxygen (CMRO2) (N=118, men=56, ages 18 to 74). We further showed that, before the mean menopausal age of 51years old, female and male groups have similar rates of CMRO2 increase (P=0.015) and there was no interaction between age and sex effects (P=0.85). However, when using data from the entire age range, women have a slower rate of CMRO2 change when compared to men (P<0.001 for age×sex interaction term). Thus, menopause and estrogen level may have played a role in this sex difference. Our data also revealed a possible circadian rhythm of CMRO2 in that brain metabolic rate is greater at noon than in the morning (P=0.02). This study reveals a potential neurobiological mechanism for age-related compensation in brain function and also suggests a sex-difference in its temporal pattern.
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215
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Arterial spin labeling characterization of cerebral perfusion during normal maturation from late childhood into adulthood: normal 'reference range' values and their use in clinical studies. J Cereb Blood Flow Metab 2014; 34:776-84. [PMID: 24496173 PMCID: PMC4013758 DOI: 10.1038/jcbfm.2014.17] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 12/19/2013] [Accepted: 01/08/2014] [Indexed: 11/08/2022]
Abstract
The human brain changes structurally and functionally during adolescence, with associated alterations in cerebral perfusion. We performed dynamic arterial spin labeling (ASL) magnetic resonance imaging in healthy subjects between 8 and 32 years of age, to investigate changes in cerebral hemodynamics during normal development. In addition, an inversion recovery sequence allowed quantification of changes in longitudinal relaxation time (T₁) and equilibrium longitudinal magnetization (M₀). We present mean and reference ranges for normal values of T₁, M₀, cerebral blood flow (CBF), bolus arrival time, and bolus duration in cortical gray matter, to provide a tool for identifying age-matched perfusion abnormalities in this age range in clinical studies. Cerebral blood flow and T₁ relaxation times were negatively correlated with age, without gender or hemisphere differences. The same was true for M₀ anteriorly, but posteriorly, males but not females showed a significant decline in M₀ with increasing age. Two examples of the clinical utility of these data in identifying age-matched perfusion abnormalities, in Sturge-Weber syndrome and sickle cell anemia, are illustrated.
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216
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Assessment of tumor blood flow and its correlation with histopathologic features in skull base meningiomas and schwannomas by using pseudo-continuous arterial spin labeling images. Eur J Radiol 2014; 83:817-23. [DOI: 10.1016/j.ejrad.2014.01.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/30/2014] [Indexed: 11/21/2022]
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217
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Emeterio Nateras OS, Harrison JM, Muir ER, Zhang Y, Peng Q, Chalfin S, Gutierrez JE, Johnson DA, Kiel JW, Duong TQ. Choroidal blood flow decreases with age: an MRI study. Curr Eye Res 2014; 39:1059-67. [PMID: 24655028 DOI: 10.3109/02713683.2014.892997] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To verify that a visual fixation protocol with cued eye blinks achieves sufficient stability for magnetic resonance imaging (MRI) blood-flow measurements and to determine if choroidal blood flow (ChBF) changes with age in humans. METHODS The visual fixation stability achievable during an MRI scan was measured in five normal subjects using an eye-tracking camera outside the MRI scanner. Subjects were instructed to blink immediately after recorded MRI sound cues but to otherwise maintain stable visual fixation on a small target. Using this fixation protocol, ChBF was measured with MRI using a 3 Tesla clinical scanner in 17 normal subjects (24-68 years old). Arterial and intraocular pressures (IOP) were measured to calculate perfusion pressure in the same subjects. RESULTS The mean temporal fluctuations (standard deviation) of the horizontal and vertical displacements were 29 ± 9 μm and 38 ± 11 μm within individual fixation periods, and 50 ± 34 μm and 48 ± 19 μm across different fixation periods. The absolute displacements were 67 ± 31 μm and 81 ± 26 μm. ChBF was negatively correlated with age (R = -0.7, p = 0.003), declining 2.7 ml/100 ml/min per year. There were no significant correlations between ChBF versus perfusion pressure, arterial pressure, or IOP. There were also no significant correlations between age versus perfusion pressure, arterial pressure, or IOP. Multiple regression analysis indicated that age was the only measured independent variable that was significantly correlated with ChBF (p = 0.03). CONCLUSIONS The visual fixation protocol with cued eye blinks was effective in achieving sufficient stability for MRI measurements. ChBF had a significant negative correlation with age.
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218
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De Vis JB, Hendrikse J, Groenendaal F, de Vries LS, Kersbergen KJ, Benders MJNL, Petersen ET. Impact of neonate haematocrit variability on the longitudinal relaxation time of blood: Implications for arterial spin labelling MRI. NEUROIMAGE-CLINICAL 2014; 4:517-25. [PMID: 24818078 PMCID: PMC3984444 DOI: 10.1016/j.nicl.2014.03.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 03/13/2014] [Accepted: 03/14/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND PURPOSE The longitudinal relaxation time of blood (T 1b) is influenced by haematocrit (Hct) which is known to vary in neonates. The purpose of this study was threefold: to obtain T 1b values in neonates, to investigate how the T 1b influences quantitative arterial spin labelling (ASL), and to evaluate if known relationships between T 1b and haematocrit (Hct) hold true when Hct is measured by means of a point-of-care device. MATERIALS AND METHODS One hundred and four neonates with 120 MR scan sessions (3 T) were included. The T 1b was obtained from a T 1 inversion recovery sequence. T 1b-induced changes in ASL cerebral blood flow estimates were evaluated. The Hct was obtained by means of a point-of-care device. Linear regression analysis was used to investigate the relation between Hct and MRI-derived R1 of blood (the inverse of the T 1b). RESULTS Mean T 1b was 1.85 s (sd 0.2 s). The mean T 1b in preterm neonates was 1.77 s, 1.89 s in preterm neonates scanned at term-equivalent age (TEA) and 1.81 s in diseased neonates. The T 1b in the TEA was significantly different from the T 1b in the preterm (p < 0.05). The change in perfusion induced by the T 1b was -11% (sd 9.1%, p < 0.001). The relation between arterial-drawn Hct and R1b was R1b = 0.80 × Hct + 0.22, which falls within the confidence interval of the previously established relationships, whereas capillary-drawn Hct did not correlate with R1b. CONCLUSION We demonstrated a wide variability of the T 1b in neonates and the implications it could have in methods relying on the actual T 1b as for instance ASL. It was concluded that arterial-drawn Hct values obtained from a point-of-care device can be used to infer the T 1b whereas our data did not support the use of capillary-drawn Hct for T 1b correction.
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Key Words
- ASL, arterial spin labelling
- Arterial spin labelling
- Blood T1
- CBF, cerebral blood flow
- CBF1.6, cerebral blood flow quantified with a T1b of 1.6 s
- CBF1.85, cerebral blood flow quantified with a T1b of 1.85 s
- CBFcor, cerebral blood flow quantified with the corrected T1b
- CBFmean, cerebral blood flow quantified with the mean T1b found in our study
- Cerebral blood flow
- Haematocrit
- Hct, haematocrit
- Hctad, haematocrit measured on an arterial-drawn blood sample
- Hctcd, haematocrit measured on a capillary-drawn blood sample
- MRI
- MRI, magnetic resonance imaging
- NPD, normalized perfusion difference
- Neonates
- PCA, postconceptional age
- PNA, postnatal age
- POCT, point-of-care test
- R1b, longitudinal relaxation rate constant of blood
- T1b, longitudinal relaxation time of blood
- TEA, term-equivalent age
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Affiliation(s)
- J B De Vis
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - J Hendrikse
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - F Groenendaal
- Department of Neonatology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - L S de Vries
- Department of Neonatology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - K J Kersbergen
- Department of Neonatology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - M J N L Benders
- Department of Neonatology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - E T Petersen
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands ; Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
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219
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Lorthois S, Duru P, Billanou I, Quintard M, Celsis P. Kinetic modeling in the context of cerebral blood flow quantification by H2(15)O positron emission tomography: the meaning of the permeability coefficient in Renkin-Crone׳s model revisited at capillary scale. J Theor Biol 2014; 353:157-69. [PMID: 24637002 DOI: 10.1016/j.jtbi.2014.03.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 02/21/2014] [Accepted: 03/04/2014] [Indexed: 10/25/2022]
Abstract
One the one hand, capillary permeability to water is a well-defined concept in microvascular physiology, and linearly relates the net convective or diffusive mass fluxes (by unit area) to the differences in pressure or concentration, respectively, that drive them through the vessel wall. On the other hand, the permeability coefficient is a central parameter introduced when modeling diffusible tracers transfer from blood vessels to tissue in the framework of compartmental models, in such a way that it is implicitly considered as being identical to the capillary permeability. Despite their simplifying assumptions, such models are at the basis of blood flow quantification by H2(15)O Positron Emission Tomgraphy. In the present paper, we use fluid dynamic modeling to compute the transfers of H2(15)O between the blood and brain parenchyma at capillary scale. The analysis of the so-obtained kinetic data by the Renkin-Crone model, the archetypal compartmental model, demonstrates that, in this framework, the permeability coefficient is highly dependent on both flow rate and capillary radius, contrarily to the central hypothesis of the model which states that it is a physiological constant. Thus, the permeability coefficient in Renkin-Crone׳s model is not conceptually identical to the physiologic permeability as implicitly stated in the model. If a permeability coefficient is nevertheless arbitrarily chosen in the computed range, the flow rate determined by the Renkin-Crone model can take highly inaccurate quantitative values. The reasons for this failure of compartmental approaches in the framework of brain blood flow quantification are discussed, highlighting the need for a novel approach enabling to fully exploit the wealth of information available from PET data.
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Affiliation(s)
- Sylvie Lorthois
- CNRS, IMFT (Institut de Mécanique des Fluides de Toulouse), Allée Camille Soula, F-31400 Toulouse, France; Université de Toulouse, INPT, UPS, IMFT (Institut de Mécanique des Fluides de Toulouse), Allée Camille Soula, F-31400 Toulouse, France.
| | - Paul Duru
- Université de Toulouse, INPT, UPS, IMFT (Institut de Mécanique des Fluides de Toulouse), Allée Camille Soula, F-31400 Toulouse, France; CNRS, IMFT (Institut de Mécanique des Fluides de Toulouse), Allée Camille Soula, F-31400 Toulouse, France
| | - Ian Billanou
- Université de Toulouse, INPT, UPS, IMFT (Institut de Mécanique des Fluides de Toulouse), Allée Camille Soula, F-31400 Toulouse, France; CNRS, IMFT (Institut de Mécanique des Fluides de Toulouse), Allée Camille Soula, F-31400 Toulouse, France
| | - Michel Quintard
- CNRS, IMFT (Institut de Mécanique des Fluides de Toulouse), Allée Camille Soula, F-31400 Toulouse, France; Université de Toulouse, INPT, UPS, IMFT (Institut de Mécanique des Fluides de Toulouse), Allée Camille Soula, F-31400 Toulouse, France
| | - Pierre Celsis
- INSERM, UMR 825, Cerebral Imaging and Neurological Handicaps, Toulouse F-31000, France; Université Toulouse III Paul Sabatier, UMR 825, Toulouse F-31000, France
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220
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Kim T, Richard Jennings J, Kim SG. Regional cerebral blood flow and arterial blood volume and their reactivity to hypercapnia in hypertensive and normotensive rats. J Cereb Blood Flow Metab 2014; 34:408-14. [PMID: 24252849 PMCID: PMC3948115 DOI: 10.1038/jcbfm.2013.197] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 10/15/2013] [Accepted: 10/21/2013] [Indexed: 11/09/2022]
Abstract
Chronic hypertension induces cerebrovascular remodeling, changing the inner diameter and elasticity of arterial vessels. To examine cerebrovascular morphologic changes and vasodilatory impairment in early-stage hypertension, we measured baseline (normocapnic) cerebral arterial blood volume (CBV(a)) and cerebral blood flow (CBF) as well as hypercapnia-induced dynamic vascular responses in animal models. All experiments were performed with young (3 to 4 month old) spontaneously hypertensive rats (SHR) and control Wistar-Kyoto rats (WKY) under ∼1% isoflurane anesthesia at 9.4 Tesla. Baseline regional CBF values were similar in both animal groups, whereas SHR had significantly lower CBV(a) values, especially in the hippocampus area. As CBF is maintained by adjusting arterial diameters within the autoregulatory blood pressure range, CBV(a) is likely more sensitive than CBF for detecting hypertensive-mediated alterations. Unexpectedly, hypercapnia-induced CBF and blood-oxygenation-level-dependent (BOLD) response were significantly higher in SHR as compared with WKY, and the CBF reactivity was highly correlated with the BOLD reactivity in both groups. The higher reactivity in early-stage hypertensive animals indicates no significant vascular remodeling occurred. At later stages of hypertension, the reduced vascular reactivity is expected. Thus, CBF and CBV(a) mapping may provide novel insights into regional cerebrovascular impairment in hypertension and its progression as hypertension advances.
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Affiliation(s)
- Tae Kim
- Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - J Richard Jennings
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Seong-Gi Kim
- 1] Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA [2] Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Daejeon, Republic of Korea [3] Department of Biological Sciences, Sungkyunkwan University, Suwon, Republic of Korea
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221
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Liu P, Huang H, Rollins N, Chalak LF, Jeon T, Halovanic C, Lu H. Quantitative assessment of global cerebral metabolic rate of oxygen (CMRO2) in neonates using MRI. NMR IN BIOMEDICINE 2014; 27:332-40. [PMID: 24399806 PMCID: PMC3970939 DOI: 10.1002/nbm.3067] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/27/2013] [Accepted: 11/29/2013] [Indexed: 05/30/2023]
Abstract
The cerebral metabolic rate of oxygen (CMRO2) is the rate of oxygen consumption by the brain, and is thought to be a direct index of energy homeostasis and brain health. However, in vivo measurement of CMRO2 is challenging, in particular for the neonatal population, in whom conventional radiotracer methods are not applicable because of safety concerns. In this study, we propose a method to quantify global CMRO2 in neonates based on arteriovenous differences in oxygen content, and employ separate measurements of oxygenation and cerebral blood flow (CBF) parameters. Specifically, arterial and venous oxygenation levels were determined with pulse oximetry and the novel T2 relaxation under spin tagging (TRUST) MRI, respectively. Global CBF was measured with phase contrast (PC) flow velocity MRI. The proposed method was implemented on a standard 3-T MRI scanner without the need for any exogenous tracers, and the total scan duration was less than 5 min. We demonstrated the feasibility of this method in 12 healthy neonates within an age range of 35-42 gestational weeks. CMRO2 values were successfully obtained from 10 neonates. It was found that the average CMRO2 in this age range was 38.3 ± 17.7 µmol/100 g/min and was positively correlated with age (p = 0.007; slope, 5.2 µmol/100 g/min per week), although the highest CMRO2 value in this age range was still less than half of the adult level. Test-retest studies showed a coefficient of variation of 5.8 ± 2.2% between repeated CMRO2 measurements. In addition, given the highly variable blood flow velocity within this age range, it is recommended that the TRUST labeling thickness and position should be determined on a subject-by-subject basis, and an automatic algorithm was developed for this purpose. Although this method provides a global CMRO2 measure only, the clinical significance of an energy consumption marker and the convenience of this technique may make it a useful tool in the functional assessment of the neonatal population.
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Affiliation(s)
- Peiying Liu
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Texas, United States
| | - Hao Huang
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Texas, United States
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Nancy Rollins
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Children’s Medical Center of Dallas, Dallas, Texas, United States
| | - Lina F. Chalak
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Tina Jeon
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Texas, United States
| | - Cathy Halovanic
- Children’s Medical Center of Dallas, Dallas, Texas, United States
| | - Hanzhang Lu
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Texas, United States
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
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222
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Qian S, Jiang Q, Liu K, Li B, Li M, Li L, Yang X, Yang Z, Sun G. Effects of short-term environmental hyperthermia on patterns of cerebral blood flow. Physiol Behav 2014; 128:99-107. [PMID: 24530482 DOI: 10.1016/j.physbeh.2014.01.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 01/11/2014] [Accepted: 01/26/2014] [Indexed: 10/25/2022]
Abstract
Environmental hyperthermia is a very common risk factor for many occupations, however, its potential influences on cerebral circulation remain obscure. In this study, 20 participants underwent two simulated environmental thermal conditions (50 °C/25 °C, 1 h), and their cerebral blood flows (CBFs) were quantified using a pseudo-continuous arterial spin labeling (ASL) MR imaging. During the experiment, the physiological parameters, including rectal temperature, arterial blood pressure and weight loss, heart rate and respiration rate, were recorded, and a visual analog scale (VAS) test was performed during both conditions to evaluate the psychological state including vigilance, anxiety, vigor, confidence, anger, nervousness, drowsiness, and loquacity. After scanning, a highly-demanding attentional task--the psychomotor vigilance test (PVT) was performed for behavioral performance evaluation. Compared with that during normothermic condition, the global CBF (gCBF) during hyperthermic condition showed a tendency of decrease, but no significant differences. Regional CBFs (rCBFs) were significantly altered mainly in the prefrontal cortex, somatosensory areas and limbic system. Physiological detection revealed significantly decreased diastolic pressure and systolic pressure and accelerated respiration rate. Furthermore, linear multivariate regression analysis showed that altered rCBFs in several regions could be predicted by physiological (systolic pressure, rectal temperature) and psychological (vigilance, drowsiness, nervousness, anger) changes. And PVT revealed significantly slower attentional reaction during hyperthermia, and the longer reaction time was correlated with the altered rCBF in the left dorsolateral prefrontal cortex (DLPFC). These findings suggested that during short-term hyperthermia gCBF might remain relatively stable under the integrated effect of physiological changes and cerebral auto-regulation, rather than decreased solely dependently on hyperthermia-induced physiological changes. Furthermore, altered regional blood distribution might be accounted for neural activity of thermal sensation and regulation, mood state and cognitive changes.
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Affiliation(s)
- Shaowen Qian
- Department of Medical Imaging, Jinan Military General Hospital, Shandong, PR China
| | - Qingjun Jiang
- Department of Medical Imaging, Jinan Military General Hospital, Shandong, PR China
| | - Kai Liu
- Department of Medical Imaging, Jinan Military General Hospital, Shandong, PR China
| | - Bo Li
- Department of Medical Imaging, Jinan Military General Hospital, Shandong, PR China
| | - Min Li
- Department of Medical Imaging, Jinan Military General Hospital, Shandong, PR China
| | - Li Li
- Department of Medical Imaging, Jinan Military General Hospital, Shandong, PR China
| | - Xiao Yang
- Department of Medical Imaging, Jinan Military General Hospital, Shandong, PR China
| | - Zhen Yang
- Department of Medical Imaging, Jinan Military General Hospital, Shandong, PR China
| | - Gang Sun
- Department of Medical Imaging, Jinan Military General Hospital, Shandong, PR China.
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223
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Heijtel DFR, Mutsaerts HJMM, Bakker E, Schober P, Stevens MF, Petersen ET, van Berckel BNM, Majoie CBLM, Booij J, van Osch MJP, Vanbavel E, Boellaard R, Lammertsma AA, Nederveen AJ. Accuracy and precision of pseudo-continuous arterial spin labeling perfusion during baseline and hypercapnia: a head-to-head comparison with ¹⁵O H₂O positron emission tomography. Neuroimage 2014; 92:182-92. [PMID: 24531046 DOI: 10.1016/j.neuroimage.2014.02.011] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 01/28/2014] [Accepted: 02/03/2014] [Indexed: 11/18/2022] Open
Abstract
Measurements of the cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) provide useful information about cerebrovascular condition and regional metabolism. Pseudo-continuous arterial spin labeling (pCASL) is a promising non-invasive MRI technique to quantitatively measure the CBF, whereas additional hypercapnic pCASL measurements are currently showing great promise to quantitatively assess the CVR. However, the introduction of pCASL at a larger scale awaits further evaluation of the exact accuracy and precision compared to the gold standard. (15)O H₂O positron emission tomography (PET) is currently regarded as the most accurate and precise method to quantitatively measure both CBF and CVR, though it is one of the more invasive methods as well. In this study we therefore assessed the accuracy and precision of quantitative pCASL-based CBF and CVR measurements by performing a head-to-head comparison with (15)O H₂O PET, based on quantitative CBF measurements during baseline and hypercapnia. We demonstrate that pCASL CBF imaging is accurate during both baseline and hypercapnia with respect to (15)O H₂O PET with a comparable precision. These results pave the way for quantitative usage of pCASL MRI in both clinical and research settings.
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Affiliation(s)
- D F R Heijtel
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands.
| | - H J M M Mutsaerts
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
| | - E Bakker
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - P Schober
- Department of Anesthesiology, VU University Medical Center, Amsterdam, The Netherlands
| | - M F Stevens
- Department of Anesthesiology, Academic Medical Center, Amsterdam, The Netherlands
| | - E T Petersen
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - B N M van Berckel
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - C B L M Majoie
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
| | - J Booij
- Department of Nuclear Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - M J P van Osch
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - E Vanbavel
- Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
| | - R Boellaard
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - A A Lammertsma
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - A J Nederveen
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
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224
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Qin Q, Huang AJ, Hua J, Desmond JE, Stevens RD, van Zijl PC. Three-dimensional whole-brain perfusion quantification using pseudo-continuous arterial spin labeling MRI at multiple post-labeling delays: accounting for both arterial transit time and impulse response function. NMR IN BIOMEDICINE 2014; 27:116-28. [PMID: 24307572 PMCID: PMC3947417 DOI: 10.1002/nbm.3040] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 08/26/2013] [Accepted: 08/27/2013] [Indexed: 05/12/2023]
Abstract
Measurement of the cerebral blood flow (CBF) with whole-brain coverage is challenging in terms of both acquisition and quantitative analysis. In order to fit arterial spin labeling-based perfusion kinetic curves, an empirical three-parameter model which characterizes the effective impulse response function (IRF) is introduced, which allows the determination of CBF, the arterial transit time (ATT) and T(1,eff). The accuracy and precision of the proposed model were compared with those of more complicated models with four or five parameters through Monte Carlo simulations. Pseudo-continuous arterial spin labeling images were acquired on a clinical 3-T scanner in 10 normal volunteers using a three-dimensional multi-shot gradient and spin echo scheme at multiple post-labeling delays to sample the kinetic curves. Voxel-wise fitting was performed using the three-parameter model and other models that contain two, four or five unknown parameters. For the two-parameter model, T(1,eff) values close to tissue and blood were assumed separately. Standard statistical analysis was conducted to compare these fitting models in various brain regions. The fitted results indicated that: (i) the estimated CBF values using the two-parameter model show appreciable dependence on the assumed T(1,eff) values; (ii) the proposed three-parameter model achieves the optimal balance between the goodness of fit and model complexity when compared among the models with explicit IRF fitting; (iii) both the two-parameter model using fixed blood T1 values for T(1,eff) and the three-parameter model provide reasonable fitting results. Using the proposed three-parameter model, the estimated CBF (46 ± 14 mL/100 g/min) and ATT (1.4 ± 0.3 s) values averaged from different brain regions are close to the literature reports; the estimated T(1,eff) values (1.9 ± 0.4 s) are higher than the tissue T1 values, possibly reflecting a contribution from the microvascular arterial blood compartment.
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Affiliation(s)
- Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological
Science, Division of MR Research, The Johns Hopkins University School of Medicine,
Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy
Krieger Institute, Baltimore, MD, USA
| | - Alan J. Huang
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy
Krieger Institute, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University,
Baltimore, MD, USA
| | - Jun Hua
- The Russell H. Morgan Department of Radiology and Radiological
Science, Division of MR Research, The Johns Hopkins University School of Medicine,
Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy
Krieger Institute, Baltimore, MD, USA
| | - John E. Desmond
- Department of Neurology and Neurosurgery, The Johns Hopkins
University, Baltimore, MD, USA
| | - Robert D. Stevens
- The Russell H. Morgan Department of Radiology and Radiological
Science, Division of MR Research, The Johns Hopkins University School of Medicine,
Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy
Krieger Institute, Baltimore, MD, USA
- Department of Neurology and Neurosurgery, The Johns Hopkins
University, Baltimore, MD, USA
- Department of Anesthesiology and Critical Care Medicine, The Johns
Hopkins University, Baltimore, MD, USA
| | - Peter C.M. van Zijl
- The Russell H. Morgan Department of Radiology and Radiological
Science, Division of MR Research, The Johns Hopkins University School of Medicine,
Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy
Krieger Institute, Baltimore, MD, USA
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225
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Rajendran R, Huang W, Tang AMY, Liang JM, Choo S, Reese T, Hentze H, van Boxtel S, Cliffe A, Rogers K, Henry B, Chuang KH. Early detection of antiangiogenic treatment responses in a mouse xenograft tumor model using quantitative perfusion MRI. Cancer Med 2014; 3:47-60. [PMID: 24403176 PMCID: PMC3930389 DOI: 10.1002/cam4.177] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 10/15/2013] [Accepted: 11/08/2013] [Indexed: 02/06/2023] Open
Abstract
Angiogenesis plays a major role in tumor growth and metastasis, with tumor perfusion regarded as a marker for angiogenesis. To evaluate antiangiogenic treatment response in vivo, we investigated arterial spin labeling (ASL) magnetic resonance imaging (MRI) to measure tumor perfusion quantitatively. Chronic and 24-h acute treatment responses to bevacizumab were assessed by ASL and dynamic-contrast-enhanced (DCE) MRI in the A498 xenograft mouse model. After the MRI, tumor vasculature was assessed by CD34 staining. After 39 days of chronic treatment, tumor perfusion decreased to 44.8 ± 16.1 mL/100 g/min (P < 0.05), compared to 92.6 ± 42.9 mL/100 g/min in the control group. In the acute treatment study, tumor perfusion in the treated group decreased from 107.2 ± 32.7 to 73.7 ± 27.8 mL/100 g/min (P < 0.01; two-way analysis of variance), as well as compared with control group post dosing. A significant reduction in vessel density and vessel size was observed after the chronic treatment, while only vessel size was reduced 24 h after acute treatment. The tumor perfusion correlated with vessel size (r = 0.66; P < 0.005) after chronic, but not after acute treatment. The results from DCE-MRI also detected a significant change between treated and control groups in both chronic and acute treatment studies, but not between 0 and 24 h in the acute treatment group. These results indicate that tumor perfusion measured by MRI can detect early vascular responses to antiangiogenic treatment. With its noninvasive and quantitative nature, ASL MRI would be valuable for longitudinal assessment of tumor perfusion and in translation from animal models to human.
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Affiliation(s)
- Reshmi Rajendran
- MRI Group, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore
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226
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Muir ER, Watts LT, Tiwari YV, Bresnen A, Shen Q, Duong TQ. Quantitative cerebral blood flow measurements using MRI. Methods Mol Biol 2014; 1135:205-11. [PMID: 24510866 DOI: 10.1007/978-1-4939-0320-7_17] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Magnetic resonance imaging can be utilized as a quantitative and noninvasive method to image cerebral blood flow. The two most common techniques used to detect cerebral blood flow are dynamic susceptibility contrast (DSC) perfusion MRI and arterial spin labeling perfusion MRI. Herein we describe the use of these two techniques to measure cerebral blood flow in rodents, including methods, analysis, and important considerations when utilizing these techniques.
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Affiliation(s)
- Eric R Muir
- Department of Ophthalmology, Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
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227
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Foley LM, Hitchens TK, Barbe B, Zhang F, Ho C, Rao GR, Nemoto EM. Quantitative temporal profiles of penumbra and infarction during permanent middle cerebral artery occlusion in rats. Transl Stroke Res 2013; 1:220-9. [PMID: 21666857 DOI: 10.1007/s12975-010-0032-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The basic premise of neuroprotection in acute stroke is the presence of salvageable tissue, but the spatiotemporal volume profiles of the penumbra and infarction remain poorly defined in preclinical animal models of acute stroke used to evaluate therapies for clinical application. Our aim was to define these profiles using magnetic resonance imaging (MRI) quantitative cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) for dual-parameter voxel analysis in the rat suture permanent middle cerebral artery occlusion (pMCAO) model. Eleven male Sprague Dawley rats were subjected to pMCAO with MRI measurements of quantitative CBF and ADC at baseline, over the first 4 h (n=9) and at 7, 14, and 21 days (n=4). Voxel analysis of CBF and ADC was used to characterize brain tissue ischemic transitions. Penumbra, core, and hyperemic infarction volumes were significantly elevated (P<0.05) and unchanged over the first 4 h of pMCAO while the total lesion volume progressively rose. At 7, 14, and 21 days, tissue compartment transitions reflected infarction, tissue cavitation, and selective ischemic neuronal necrosis. Anatomical distribution of penumbra and core revealed marked heterogeneity with penumbra scattered within core and penumbra persisting even after 4 h of permanent MCAO.
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Affiliation(s)
- Lesley M Foley
- Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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228
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Grözinger G, Pohmann R, Schick F, Grosse U, Syha R, Brechtel K, Rittig K, Martirosian P. Perfusion measurements of the calf in patients with peripheral arterial occlusive disease before and after percutaneous transluminal angioplasty using Mr arterial spin labeling. J Magn Reson Imaging 2013; 40:980-7. [DOI: 10.1002/jmri.24463] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 09/08/2013] [Indexed: 01/14/2023] Open
Affiliation(s)
- Gerd Grözinger
- Division of Diagnostic Radiology Department of Diagnostic and Interventional Radiology; University of Tübingen; Tübingen Germany
- Section on Experimental Radiology Department of Diagnostic and Interventional Radiology; University of Tübingen; Tübingen Germany
| | - Rolf Pohmann
- Max Planck Institute for Biological Cybernetics; Magnetic Resonance Center; Tübingen Tübingen Germany
| | - Fritz Schick
- Section on Experimental Radiology Department of Diagnostic and Interventional Radiology; University of Tübingen; Tübingen Germany
| | - Ulrich Grosse
- Division of Diagnostic Radiology Department of Diagnostic and Interventional Radiology; University of Tübingen; Tübingen Germany
- Section on Experimental Radiology Department of Diagnostic and Interventional Radiology; University of Tübingen; Tübingen Germany
| | - Roland Syha
- Division of Diagnostic Radiology Department of Diagnostic and Interventional Radiology; University of Tübingen; Tübingen Germany
- Section on Experimental Radiology Department of Diagnostic and Interventional Radiology; University of Tübingen; Tübingen Germany
| | - Klaus Brechtel
- Division of Diagnostic Radiology Department of Diagnostic and Interventional Radiology; University of Tübingen; Tübingen Germany
| | - Kilian Rittig
- Department of Internal Medicine Division of Endocrinology Diabetology Angiology Nephrology and Clinical Chemistry; University of Tübingen; Tübingen Germany
| | - Petros Martirosian
- Section on Experimental Radiology Department of Diagnostic and Interventional Radiology; University of Tübingen; Tübingen Germany
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229
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Gray matter contamination in arterial spin labeling white matter perfusion measurements in patients with dementia. NEUROIMAGE-CLINICAL 2013; 4:139-44. [PMID: 24371796 PMCID: PMC3871287 DOI: 10.1016/j.nicl.2013.11.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Revised: 11/05/2013] [Accepted: 11/06/2013] [Indexed: 01/28/2023]
Abstract
Introduction White matter (WM) perfusion measurements with arterial spin labeling can be severely contaminated by gray matter (GM) perfusion signal, especially in the elderly. The current study investigates the spatial extent of GM contamination by comparing perfusion signal measured in the WM with signal measured outside the brain. Material and methods Four minute 3T pseudo-continuous arterial spin labeling scans were performed in 41 elderly subjects with cognitive impairment. Outward and inward geodesic distance maps were created, based on dilations and erosions of GM and WM masks. For all outward and inward geodesic distances, the mean CBF was calculated and compared. Results GM contamination was mainly found in the first 3 subcortical WM voxels and had only minor influence on the deep WM signal (distances 4 to 7 voxels). Perfusion signal in the WM was significantly higher than perfusion signal outside the brain, indicating the presence of WM signal. Conclusion These findings indicate that WM perfusion signal can be measured unaffected by GM contamination in elderly patients with cognitive impairment. GM contamination can be avoided by the erosion of WM masks, removing subcortical WM voxels from the analysis. These results should be taken into account when exploring the use of WM perfusion as micro-vascular biomarker. A single slice distance analysis was performed. Perfusion signal in the white matter was compared with signal outside the brain. The application of erosion was compared with removal of partial volume voxels. White matter perfusion signal can be distinguished from gray matter contamination. The erosion of three voxels is warranted to avoid gray matter contamination.
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230
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Shih YYI, De La Garza BH, Huang S, Li G, Wang L, Duong TQ. Comparison of retinal and cerebral blood flow between continuous arterial spin labeling MRI and fluorescent microsphere techniques. J Magn Reson Imaging 2013; 40:609-15. [PMID: 24227681 DOI: 10.1002/jmri.24407] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 08/05/2013] [Indexed: 01/09/2023] Open
Abstract
PURPOSE To compare basal retinal and cerebral blood flow (BF) values using continuous arterial spin labeling (CASL) MRI and fluorescent microspheres. MATERIALS AND METHODS A total of 41 animals were used. BF was measured using an established microsphere technique (a mixture of 2.5 million 8 μm green and 0.5 million 10 μm blue fluorescent microspheres) and CASL MRI blood flow measurement in the rat retina and brain at 7 Tesla (T) and 11.7T, respectively. RESULTS Retinal BF by MRI was 1.18 ± 0.57 mL/g/min and choroidal BF was 8.14 ± 1.8 mL/g/min (n = 6). Microsphere retinal BF was 9.12 ± 2.8 μL/min per tissue and choroidal BF was 73.38 ± 44 μL/min per tissue (n = 18), corresponding to a retinal BF value of 1.22 ± 0.36 mL/g/min by means of a wet weight conversion. The wet-weight of the choroid could not be determined. To corroborate our findings, cerebral BF (CBF) by MRI was also analyzed. In the cerebral cortices, CBF was 0.91 ± 0.29 mL/g/min (n = 14) by CASL MRI and 1.09 ± 0.37 mL/g/min (n = 6) by microspheres. There were no significant differences found between MRI and microsphere blood flow in the retina and brain. CONCLUSION BF values in the rat retina and cerebral cortex by MRI are in agreement with those obtained by the microsphere technique.
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Affiliation(s)
- Yen-Yu I Shih
- Departments of Neurology, Biomedical Research Imaging Center, and Biomedical Engineering, University of North Carolina, Chapel Hill, North Carolina, USA; Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
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231
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van Golen LW, Kuijer JP, Huisman MC, IJzerman RG, Barkhof F, Diamant M, Lammertsma AA. Quantification of cerebral blood flow in healthy volunteers and type 1 diabetic patients: Comparison of MRI arterial spin labeling and [15O]H2O positron emission tomography (PET). J Magn Reson Imaging 2013; 40:1300-9. [DOI: 10.1002/jmri.24484] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Accepted: 09/28/2013] [Indexed: 11/06/2022] Open
Affiliation(s)
- Larissa W. van Golen
- Diabetes Center/ Department of Internal Medicine; VU University Medical Center; Amsterdam The Netherlands
| | - Joost P.A. Kuijer
- Department of Physics and Medical Technology, Neuroscience Campus Amsterdam; VU University Medical Center; Amsterdam The Netherlands
| | - Marc C. Huisman
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam; VU University Medical Center; Amsterdam The Netherlands
| | - Richard G. IJzerman
- Diabetes Center/ Department of Internal Medicine; VU University Medical Center; Amsterdam The Netherlands
| | - Frederik Barkhof
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam; VU University Medical Center; Amsterdam The Netherlands
| | - Michaela Diamant
- Diabetes Center/ Department of Internal Medicine; VU University Medical Center; Amsterdam The Netherlands
| | - Adriaan A. Lammertsma
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam; VU University Medical Center; Amsterdam The Netherlands
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232
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Petr J, Schramm G, Hofheinz F, Langner J, van den Hoff J. Modeling magnetization transfer effects of Q2TIPS bolus saturation in multi-TI pulsed arterial spin labeling. Magn Reson Med 2013; 72:1007-14. [PMID: 24194169 DOI: 10.1002/mrm.25011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 09/17/2013] [Accepted: 10/04/2013] [Indexed: 11/07/2022]
Abstract
PURPOSE To estimate the relaxation time changes during Q2TIPS bolus saturation caused by magnetization transfer effects and to propose and evaluate an extended model for perfusion quantification which takes this into account. METHOD Three multi inversion-time pulsed arterial spin labeling sequences with different bolus saturation duration were acquired for five healthy volunteers. Magnetization transfer exchange rates in tissue and blood were obtained from control image saturation recovery. Cerebral blood flow (CBF) obtained using the extended model and the standard model was compared. RESULTS A decrease of obtained CBF of 6% (10%) was observed in grey matter when the duration of bolus saturation increased from 600 to 900 ms (1200 ms). This decrease was reduced to 1.6% (2.8%) when the extended quantification model was used. Compared with the extended model, the standard model underestimated CBF in grey matter by 9.7, 15.0, and 18.7% for saturation durations 600, 900, and 1200 ms, respectively. Results for simulated single inversion-time data showed 5-16% CBF underestimation depending on blood arrival time and bolus saturation duration. CONCLUSION Magnetization transfer effects caused by bolus saturation pulses should not be ignored when performing quantification as they can cause appreciable underestimation of the CBF.
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Affiliation(s)
- Jan Petr
- Department of Positron Emission Tomography, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
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233
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Cerebral blood flow quantification using vessel-encoded arterial spin labeling. J Cereb Blood Flow Metab 2013; 33:1716-24. [PMID: 23921895 PMCID: PMC3824178 DOI: 10.1038/jcbfm.2013.129] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/08/2013] [Accepted: 07/09/2013] [Indexed: 12/20/2022]
Abstract
Arterial spin labeling (ASL) techniques are gaining popularity for visualizing and quantifying cerebral blood flow (CBF) in a range of patient groups. However, most ASL methods lack vessel-selective information, which is important for the assessment of collateral flow and the arterial supply to lesions. In this study, we explored the use of vessel-encoded pseudocontinuous ASL (VEPCASL) with multiple postlabeling delays to obtain individual quantitative CBF and bolus arrival time maps for each of the four main brain-feeding arteries and compared the results against those obtained with conventional pseudocontinuous ASL (PCASL) using matched scan time. Simulations showed that PCASL systematically underestimated CBF by up to 37% in voxels supplied by two arteries, whereas VEPCASL maintained CBF accuracy since each vascular component is treated separately. Experimental results in healthy volunteers showed that there is no systematic bias in the CBF estimates produced by VEPCASL and that the signal-to-noise ratio of the two techniques is comparable. Although more complex acquisition and image processing is required and the potential for motion sensitivity is increased, VEPCASL provides comparable data to PCASL but with the added benefit of vessel-selective information. This could lead to more accurate CBF estimates in patients with a significant collateral flow.
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234
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Hare HV, Germuska M, Kelly ME, Bulte DP. Comparison of CO2 in air versus carbogen for the measurement of cerebrovascular reactivity with magnetic resonance imaging. J Cereb Blood Flow Metab 2013; 33:1799-805. [PMID: 23921896 PMCID: PMC3824179 DOI: 10.1038/jcbfm.2013.131] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 07/10/2013] [Accepted: 07/11/2013] [Indexed: 01/16/2023]
Abstract
Measurement of cerebrovascular reactivity (CVR) can give valuable information about existing pathology and the risk of adverse events, such as stroke. A common method of obtaining regional CVR values is by measuring the blood flow response to carbon dioxide (CO2)-enriched air using arterial spin labeling (ASL) or blood oxygen level-dependent (BOLD) imaging. Recently, several studies have used carbogen gas (containing only CO2 and oxygen) as an alternative stimulus. A direct comparison was performed between CVR values acquired by ASL and BOLD imaging using stimuli of (1) 5% CO2 in air and (2) 5% CO2 in oxygen (carbogen-5). Although BOLD and ASL CVR values are shown to be correlated for CO2 in air (mean response 0.11±0.03% BOLD, 4.46±1.80% ASL, n=16 hemispheres), this correlation disappears during a carbogen stimulus (0.36±0.06% BOLD, 4.97±1.30% ASL). It is concluded that BOLD imaging should generally not be used in conjunction with a carbogen stimulus when measuring CVR, and that care must be taken when interpreting CVR as measured by ASL, as values obtained from different stimuli (CO2 in air versus carbogen) are not directly comparable.
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Affiliation(s)
- Hannah V Hare
- 1] Nuffield Department of Clinical Neurosciences, FMRIB Centre, University of Oxford, Oxford, UK [2] Department of Physics, University of Oxford, Oxford, UK
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235
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Ciris PA, Qiu M, Constable RT. Noninvasive MRI measurement of the absolute cerebral blood volume-cerebral blood flow relationship during visual stimulation in healthy humans. Magn Reson Med 2013; 72:864-75. [PMID: 24151246 DOI: 10.1002/mrm.24984] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 08/12/2013] [Accepted: 09/13/2013] [Indexed: 01/02/2023]
Abstract
PURPOSE The relationship between cerebral blood volume (CBV) and cerebral blood flow (CBF) underlies blood oxygenation level-dependent functional MRI signal. This study investigates the potential for improved characterization of the CBV-CBF relationship in humans, and examines sex effects as well as spatial variations in the CBV-CBF relationship. METHODS Healthy subjects were imaged noninvasively at rest and during visual stimulation, constituting the first MRI measurement of the absolute CBV-CBF relationship in humans with complete coverage of the functional areas of interest. RESULTS CBV and CBF estimates were consistent with the literature, and their relationship varied both spatially and with sex. In a region of interest with stimulus-induced activation in CBV and CBF at a significance level of the P < 0.05, a power function fit resulted in CBV = 2.1 CBF(0.32) across all subjects, CBV = 0.8 CBF(0.51) in females and CBV = 4.4 CBF(0.15) in males. Exponents decreased in both sexes as ROIs were expanded to include less significantly activated regions. CONCLUSION Consideration for potential sex-related differences, as well as regional variations under a range of physiological states, may reconcile some of the variation across literature and advance our understanding of the underlying cerebrovascular physiology.
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Affiliation(s)
- Pelin Aksit Ciris
- Department of Biomedical Engineering, Yale University, School of Medicine, Magnetic Resonance Research Center, New Haven, Connecticut, USA
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236
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Hales PW, Phipps KP, Kaur R, Clark CA. A two-stage model for in vivo assessment of brain tumor perfusion and abnormal vascular structure using arterial spin labeling. PLoS One 2013; 8:e75717. [PMID: 24098395 PMCID: PMC3788807 DOI: 10.1371/journal.pone.0075717] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 08/16/2013] [Indexed: 01/01/2023] Open
Abstract
The ability to assess brain tumor perfusion and abnormalities in the vascular structure in vivo could provide significant benefits in terms of lesion diagnosis and assessment of treatment response. Arterial spin labeling (ASL) has emerged as an increasingly viable methodology for non-invasive assessment of perfusion. Although kinetic models have been developed to describe perfusion in healthy tissue, the dynamic behaviour of the ASL signal in the brain tumor environment has not been extensively studied. We show here that dynamic ASL data acquired in brain tumors displays an increased level of 'biphasic' behaviour, compared to that seen in healthy tissue. A new two-stage model is presented which more accurately describes this behaviour, and provides measurements of perfusion, pre-capillary blood volume fraction and transit time, and capillary bolus arrival time. These biomarkers offer a novel contrast in the tumor and surrounding tissue, and provide a means for measuring tumor perfusion and vascular structural abnormalities in a fully non-invasive manner.
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Affiliation(s)
- Patrick W. Hales
- Imaging and Biophysics Unit, Institute of Child Health, University College London, London, United Kingdom
- * E-mail:
| | - Kim P. Phipps
- Neuro-oncology Department, Great Ormond Street Hospital, London, United Kingdom
| | - Ramneek Kaur
- Imaging and Biophysics Unit, Institute of Child Health, University College London, London, United Kingdom
| | - Christopher A. Clark
- Imaging and Biophysics Unit, Institute of Child Health, University College London, London, United Kingdom
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237
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Rajendran R, Lew SK, Yong CX, Tan J, Wang DJJ, Chuang KH. Quantitative mouse renal perfusion using arterial spin labeling. NMR IN BIOMEDICINE 2013; 26:1225-1232. [PMID: 23592238 DOI: 10.1002/nbm.2939] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 12/30/2012] [Accepted: 02/08/2013] [Indexed: 06/02/2023]
Abstract
Information on renal perfusion is essential for the diagnosis and prognosis of kidney function. Quantification using gadolinium chelates is limited as a result of filtration through renal glomeruli and safety concerns in patients with kidney dysfunction. Arterial spin labeling MRI is a noninvasive technique for perfusion quantification that has been applied to humans and animals. However, because of the low sensitivity and vulnerability to motion and susceptibility artifacts, its application to mice has been challenging. In this article, mouse renal perfusion was studied using flow-sensitive alternating inversion recovery at 7 T. Good perfusion image quality was obtained with spin-echo echo-planar imaging after controlling for respiratory, susceptibility and fat artifacts by triggering, high-order shimming and water excitation, respectively. High perfusion was obtained in the renal cortex relative to the medulla, and signal was absent in scans carried out post mortem. Cortical perfusion increased from 397 ± 36 (mean ± standard deviation) to 476 ± 73 mL/100 g/min after switching from 100% oxygen to carbogen with 95% oxygen and 5% carbon dioxide. The perfusion in the medulla was 2.5 times lower than that in the cortex and changed from 166 ± 41 mL/100 g/min under oxygen to 203 ± 40 mL/100 g/min under carbogen. T1 decreased in both the cortex (from 1570 ± 164 to 1377 ± 72 ms, p < 0.05) and medulla (from 1788 ± 107 to 1573 ± 144 ms, p < 0.05) under carbogen relative to 100% oxygen. The results showed the potential of the use of ASL for perfusion quantification in mice and in models of renal diseases.
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Affiliation(s)
- Reshmi Rajendran
- Magnetic Resonance Imaging Group, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore
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238
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Yamamoto T, Kinoshita K, Kosaka N, Sato Y, Shioura H, Takeuchi H, Kimura H. Monitoring of extra-axial brain tumor response to radiotherapy using pseudo-continuous arterial spin labeling images: Preliminary results. Magn Reson Imaging 2013; 31:1271-7. [DOI: 10.1016/j.mri.2013.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 04/27/2013] [Accepted: 04/27/2013] [Indexed: 10/26/2022]
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In vivo evidence of increased nNOS activity in acute MPTP neurotoxicity: a functional pharmacological MRI study. BIOMED RESEARCH INTERNATIONAL 2013; 2013:964034. [PMID: 24069609 PMCID: PMC3773403 DOI: 10.1155/2013/964034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 07/21/2013] [Accepted: 08/01/2013] [Indexed: 11/21/2022]
Abstract
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin commonly used to produce an animal model of Parkinson's disease. Previous studies have suggested a critical role for neuronal nitric oxide (NO) synthase- (nNOS-) derived NO in the pathogenesis of MPTP. However, NO activity is difficult to assess in vivo due to its extremely short biological half-life, and so in vivo evidence of NO involvement in MPTP neurotoxicity remains scarce. In the present study, we utilized flow-sensitive alternating inversion recovery sequences, in vivo localized proton magnetic resonance spectroscopy, and diffusion-weighted imaging to, respectively, assess the hemodynamics, metabolism, and cytotoxicity induced by MPTP. The role of NO in MPTP toxicity was clarified further by administering a selective nNOS inhibitor, 7-nitroindazole (7-NI), intraperitoneally to some of the experimental animals prior to MPTP challenge. The transient increase in cerebral blood flow (CBF) in the cortex and striatum induced by systemic injection of MPTP was completely prevented by pretreatment with 7-NI. We provide the first in vivo evidence of increased nNOS activity in acute MPTP-induced neurotoxicity. Although the observed CBF change may be independent of the toxicogenesis of MPTP, this transient hyperperfusion state may serve as an early indicator of neuroinflammation.
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240
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Kim SG, Harel N, Jin T, Kim T, Lee P, Zhao F. Cerebral blood volume MRI with intravascular superparamagnetic iron oxide nanoparticles. NMR IN BIOMEDICINE 2013; 26. [PMID: 23208650 PMCID: PMC3700592 DOI: 10.1002/nbm.2885] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The cerebral blood volume (CBV) is a crucial physiological indicator of tissue viability and vascular reactivity. Thus, noninvasive CBV mapping has been of great interest. For this, ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles, including monocrystalline iron oxide nanoparticles, can be used as long-half-life, intravascular susceptibility agents of CBV MRI measurements. Moreover, CBV-weighted functional MRI (fMRI) with USPIO nanoparticles provides enhanced sensitivity, reduced large vessel contribution and improved spatial specificity relative to conventional blood oxygenation level-dependent fMRI, and measures a single physiological parameter that is easily interpretable. We review the physiochemical and magnetic properties, and pharmacokinetics, of USPIO nanoparticles in brief. We then extensively discuss quantifications of baseline CBV, vessel size index and functional CBV change. We also provide reviews of dose-dependent sensitivity, vascular filter function, specificity, characteristics and impulse response function of CBV fMRI. Examples of CBV fMRI specificity at the laminar and columnar resolution are provided. Finally, we briefly review the application of CBV measurements to functional and pharmacological studies in animals. Overall, the use of USPIO nanoparticles can determine baseline CBV and its changes induced by functional activity and pharmacological interventions.
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Affiliation(s)
- Seong-Gi Kim
- Neuroimaging Laboratory, Department of Radiology, University of Pittsburgh, PA, USA.
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241
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Schilling TM, Ferreira de Sá DS, Westerhausen R, Strelzyk F, Larra MF, Hallschmid M, Savaskan E, Oitzl MS, Busch HP, Naumann E, Schächinger H. Intranasal insulin increases regional cerebral blood flow in the insular cortex in men independently of cortisol manipulation. Hum Brain Mapp 2013; 35:1944-56. [PMID: 23907764 DOI: 10.1002/hbm.22304] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 02/22/2013] [Accepted: 03/18/2013] [Indexed: 01/09/2023] Open
Abstract
Insulin and cortisol play a key role in the regulation of energy homeostasis, appetite, and satiety. Little is known about the action and interaction of both hormones in brain structures controlling food intake and the processing of neurovisceral signals from the gastrointestinal tract. In this study, we assessed the impact of single and combined application of insulin and cortisol on resting regional cerebral blood flow (rCBF) in the insular cortex. After standardized periods of food restriction, 48 male volunteers were randomly assigned to receive either 40 IU intranasal insulin, 30 mg oral cortisol, both, or neither (placebo). Continuous arterial spin labeling (CASL) sequences were acquired before and after pharmacological treatment. We observed a bilateral, locally distinct rCBF increase after insulin administration in the insular cortex and the putamen. Insulin effects on rCBF were present regardless of whether participants had received cortisol or not. Our results indicate that insulin, but not cortisol, affects blood flow in human brain structures involved in the regulation of eating behavior.
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Affiliation(s)
- Thomas M Schilling
- Institute of Psychobiology, Division of Clinical Psychophysiology, University of Trier, Trier, Germany
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242
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Liu J, Zhu YS, Khan MA, Brunk E, Martin-Cook K, Weiner MF, Cullum CM, Lu H, Levine BD, Diaz-Arrastia R, Zhang R. Global brain hypoperfusion and oxygenation in amnestic mild cognitive impairment. Alzheimers Dement 2013; 10:162-70. [PMID: 23871763 DOI: 10.1016/j.jalz.2013.04.507] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 04/22/2013] [Accepted: 04/30/2013] [Indexed: 12/28/2022]
Abstract
BACKGROUND To determine if global brain hypoperfusion and oxygen hypometabolism occur in patients with amnestic mild cognitive impairment (aMCI). METHODS Thirty-two aMCI and 21 normal subjects participated. Total cerebral blood flow (TCBF), cerebral metabolic rate of oxygen (CMRO2), and brain tissue volume were measured using color-coded duplex ultrasonography (CDUS), near-infrared spectroscopy (NIRS), and MRI. TCBF was normalized by total brain tissue volume (TBV) for group comparisons (nTCBF). Cerebrovascular resistance (CVR) was calculated as mean arterial pressure divided by TCBF. RESULTS Reductions in nTCBF by 9%, CMRO2 by 11%, and an increase in CVR by 13% were observed in aMCI relative to normal subjects. No group differences in TBV were observed. nTCBF was correlated with CMRO2 in normal controls, but not in aMCI. CONCLUSIONS Global brain hypoperfusion, oxygen hypometabolism, and neurovascular decoupling observed in aMCI suggest that changes in cerebral hemodynamics occur early at a prodromal stage of Alzheimer's disease, which can be assessed using low-cost and bedside-available CDUS and NIRS technology.
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Affiliation(s)
- Jie Liu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Yong-Sheng Zhu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Muhammad Ayaz Khan
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Estee Brunk
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA
| | - Kristin Martin-Cook
- Department of Neurology and Neurotherapeutics and the Alzheimer's Disease Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Myron F Weiner
- Department of Neurology and Neurotherapeutics and the Alzheimer's Disease Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - C Munro Cullum
- Department of Neurology and Neurotherapeutics and the Alzheimer's Disease Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Hanzhang Lu
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ramon Diaz-Arrastia
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Rong Zhang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Neurology and Neurotherapeutics and the Alzheimer's Disease Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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Hasan KM, Ali H, Shad MU. Atlas-based and DTI-guided quantification of human brain cerebral blood flow: feasibility, quality assurance, spatial heterogeneity and age effects. Magn Reson Imaging 2013; 31:1445-52. [PMID: 23731534 DOI: 10.1016/j.mri.2013.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 04/27/2013] [Indexed: 12/28/2022]
Abstract
Accurate and noninvasive quantification of regional cerebral blood perfusion (CBF) of the human brain tissue would advance the study of the complex interplay between human brain structure and function, in both health and disease. Despite the plethora of works on CBF in gray matter, a detailed quantitative white matter perfusion atlas has not been presented on healthy adults using the International Consortium for Brain Mapping atlases. In this study, we present a host of assurance measures such as temporal stability, spatial heterogeneity and age effects of regional and global CBF in selected deep, cortical gray matter and white matter tracts identified and quantified using diffusion tensor imaging (DTI). We utilized whole brain high-resolution DTI combined with arterial spin labeling to quantify regional CBF on 15 healthy adults aged 23.2-57.1years. We present total brain and regional CBF, corresponding volume, mean diffusivity and fractional anisotropy spatial heterogeneity, and dependence on age as additional quality assurance measures to compare with published trends using both MRI and nuclear medicine methods. Total CBF showed a steady decrease with age in gray matter (r=-0.58; P=.03), whereas total CBF of white matter did not significantly change with age (r=0.11; P=.7). This quantitative report offers a preliminary baseline of CBF, volume and DTI measurements for the design of future multicenter and clinical studies utilizing noninvasive perfusion and DT-MRI.
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Affiliation(s)
- Khader M Hasan
- Medical School, Department of Diagnostic and Interventional Imaging, The University of Texas Health Science Center, Houston, TX 77030, USA.
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245
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Reynaud O, Geffroy F, Ciobanu L. Quantification of microvascular cerebral blood flux and late-stage tumor compartmentalization in 9L gliosarcoma using flow enhanced MRI. NMR IN BIOMEDICINE 2013; 26:699-708. [PMID: 23335424 DOI: 10.1002/nbm.2915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 12/07/2012] [Accepted: 12/07/2012] [Indexed: 06/01/2023]
Abstract
Measurements of tumor microvasculature are important to obtain an understanding of tumor angiogenesis and for the evaluation of therapies. In this work, we characterize the evolution of the microvascular flux at different stages of tumor growth in the 9L rat brain tumor model. The absolute quantification of cerebral blood flux is achieved with MRI at 7 T using the flow enhanced signal intensity (FENSI) method. FENSI flux maps were obtained between 5 and 14 days after glioma cell inoculation. Based on cerebral blood flux maps, we highlighted two main stages of tumor growth, below and above 3 mm, presenting distinct flux patterns and vascular properties. No significant difference emerged from the group analysis performed on the data collected at an early developmental stage (tumor size < 3 mm) when compared with healthy tissue. At a late developmental stage (tumor size > 3 mm), we observed a significant decrease in the cerebral blood flux inside the gliosarcoma (-33%, p < 0.01) and compartmentalization of the tumor (p < 0.05). FENSI flux maps delineated a low-flux tumor core (58 ± 17 μL/min/cm(2) ) and higher vascularized regions around the tumor periphery (85 ± 21 μL/min/cm(2) ). Histology was performed on 11 animals to finely probe the intratumor heterogeneity and microvessel density, and the results were compared with the information derived from FENSI flux maps. The hyper- and hypoperfused tumor regions revealed with FENSI at the late tumor developmental stage correlated well with the ratios of high and low blood vessel density (R(2) = 0.41) and fractional vascular surface (R(2) = 0.67) observed with fluorescence microscopy [cluster of differentiation 31 (CD31) staining].
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Affiliation(s)
- Olivier Reynaud
- Commissariat a l'Energie Atomique/DSV, I2BM, NeuroSpin, LRMN, Gif sur Yvette, France
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246
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Maleki N, Brawn J, Barmettler G, Borsook D, Becerra L. Pain response measured with arterial spin labeling. NMR IN BIOMEDICINE 2013; 26:664-673. [PMID: 23319440 PMCID: PMC3634868 DOI: 10.1002/nbm.2911] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 11/30/2012] [Accepted: 12/04/2012] [Indexed: 06/01/2023]
Abstract
The majority of functional MRI studies of pain processing in the brain use the blood oxygenation level-dependent (BOLD) imaging approach. However, the BOLD signal is complex as it depends on simultaneous changes in blood flow, vascular volume and oxygen metabolism. Arterial spin labeling (ASL) perfusion imaging is another imaging approach in which the magnetically labeled arterial water is used as an endogenous tracer that allows for direct measurement of cerebral blood flow. In this study, we assessed the pain response in the brain using a pulsed-continuous arterial spin labeling (pCASL) approach and a thermal stimulation paradigm. Using pCASL, response to noxious stimulation was detected in somatosensory cortex, anterior cingulate cortex, anterior insula, hippocampus, amygdala, thalamus and precuneus, consistent with the pain response activation patterns detected using the BOLD imaging approach. We suggest that pCASL is a reliable alternative for functional MRI pain studies in conditions in which blood flow, volume or oxygen extraction are altered or compromised.
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Affiliation(s)
- Nasim Maleki
- P.A.I.N. Group, Department of Anesthesia, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA.
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247
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Wu B, Lou X, Wu X, Ma L. Intra- and interscanner reliability and reproducibility of 3D whole-brain pseudo-continuous arterial spin-labeling MR perfusion at 3T. J Magn Reson Imaging 2013; 39:402-9. [PMID: 23723043 DOI: 10.1002/jmri.24175] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 03/20/2013] [Indexed: 11/11/2022] Open
Affiliation(s)
- Bing Wu
- Department of Radiology; Beijing Military General Hospital; Beijing China
| | - Xin Lou
- Department of Radiology; PLA General Hospital; Beijing China
| | - Xinhuai Wu
- Department of Radiology; Beijing Military General Hospital; Beijing China
| | - Lin Ma
- Department of Radiology; PLA General Hospital; Beijing China
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Li G, Shih YYI, Kiel JW, De La Garza BH, Du F, Duong TQ. MRI study of cerebral, retinal and choroidal blood flow responses to acute hypertension. Exp Eye Res 2013; 112:118-24. [PMID: 23623996 DOI: 10.1016/j.exer.2013.04.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 04/03/2013] [Accepted: 04/05/2013] [Indexed: 11/17/2022]
Abstract
Blood flow (BF) in many tissues is stable during significant fluctuations in systemic arterial blood pressure or perfusion pressure under normal conditions. The regulatory mechanisms responsible for this non-passive BF behavior include both local and neural control mechanisms. This study evaluated cerebral BF (CBF), retinal BF (RBF) and choroidal BF (ChBF) responses to acute blood pressure increases in rats using magnetic resonance imaging (MRI). A transient increase in blood pressure inside the MRI scanner was achieved by mechanically inflating a balloon catheter to occlude the descending aorta near the diaphragm. We verified the rat model of mechanical occlusion and MRI approach by first measuring blood-flow regulatory responses to changing BP in the brain under normoxia and hypercapnia where the phenomenon is well documented. Retinal and choroidal blood-flow responses to transient increased arterial pressure were then investigated. In response to an acute increase in blood pressure, RBF exhibited autoregulatory behavior and ChBF exhibited baroregulation similar to that seen in the cerebral circulation. This approach may prove useful to investigate retinal and choroidal vascular dysregulation in rat models of retinal diseases with suspected vascular etiology.
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Affiliation(s)
- Guang Li
- Research Imaging Institute, University of Texas Health Science Center, USA
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249
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Duhamel G, Prevost V, Girard OM, Callot V, Cozzone PJ. High-resolution mouse kidney perfusion imaging by pseudo-continuous arterial spin labeling at 11.75T. Magn Reson Med 2013; 71:1186-96. [DOI: 10.1002/mrm.24740] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Guillaume Duhamel
- Aix-Marseille Université, CNRS; CRMBM UMR 7339, 13385; Marseille France
| | - Valentin Prevost
- Aix-Marseille Université, CNRS; CRMBM UMR 7339, 13385; Marseille France
| | - Olivier M. Girard
- Aix-Marseille Université, CNRS; CRMBM UMR 7339, 13385; Marseille France
| | - Virginie Callot
- Aix-Marseille Université, CNRS; CRMBM UMR 7339, 13385; Marseille France
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Arkuszewski M, Krejza J, Chen R, Melhem ER. Sickle cell anemia: reference values of cerebral blood flow determined by continuous arterial spin labeling MRI. Neuroradiol J 2013; 26:191-200. [PMID: 23859242 PMCID: PMC5228728 DOI: 10.1177/197140091302600209] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 04/02/2013] [Indexed: 11/16/2022] Open
Abstract
Sickle cell anemia (SCA) is a chronic illness associated with progressive deterioration in patients' quality of life. The major complications of SCA are cerebrovascular accidents (CVA) such as asymptomatic cerebral infarct or overt stroke. The risk of CVA may be related to chronic disturbances in cerebral blood flow (CBF), but the thresholds of "normal" steady-state CBF are not well established. The reference tolerance limits of CBF can be useful to estimate the risk of CVA in asymptomatic children with SCA, who are negative for hyperemia or evidence of arterial narrowing. Continuous arterial spin labeling (CASL) MR perfusion allows for non-invasive quantification of global and regional CBF. To establish such reference tolerance limits we performed CASL MR examinations on a 3-Tesla MR scanner in a carefully selected cohort of 42 children with SCA (mean age, 8.1±3.3 years; range limits, 2.3-14.4 years; 24 females), who were not on chronic transfusion therapy, had no history of overt stroke or transient ischemic attack, were free of signs and symptoms of focal vascular territory ischemic brain injury, did not have intracranial arterial narrowing on MR angiography and were at low risk for stroke as determined by transcranial Doppler ultrasonography.
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Affiliation(s)
- M Arkuszewski
- Department of Radiology, Division of Neuroradiology, University of Pennsylvania, Philadelphia, PA, USA.
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