1
|
Saïb G, Koretsky AP, Talagala SL. Optimization of pseudo-continuous arterial spin labeling using off-resonance compensation strategies at 7T. Magn Reson Med 2021; 87:1720-1730. [PMID: 34775619 DOI: 10.1002/mrm.29070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 10/13/2021] [Accepted: 10/15/2021] [Indexed: 11/12/2022]
Abstract
PURPOSE The sensitivity of pseudo-continuous arterial spin labeling (PCASL) to off-resonance effects (ΔB0 ) is a major limitation at ultra-high field (≥7T). The aim of this study was to assess the effectiveness of different PCASL ΔB0 compensation methods at 7T and measure the labeling efficiency with off-resonance correction. THEORY AND METHODS Phase offset errors induced by ΔB0 at the feeding arteries can be compensated by adding an extra radiofrequency (RF) phase increment and transverse gradient blips into the PCASL RF pulse train. The effectiveness of an average field correction (AVGcor), a vessel-specific field-map-based correction (FMcor) and a vessel-specific prescan-based correction (PScor) were compared at 7T. After correction, the PCASL labeling efficiency was directly measured in feeding arteries downstream from the labeling location. RESULTS The perfusion signal was more uniform throughout the brain after off-resonance correction. Whole-brain average perfusion signal increased by a factor of 2.4, 2.5, and 2.1, respectively, with AVGcor, FMcor and PScor compared to acquisitions without correction. With off-resonance correction, the maximum labeling efficiency was ~0.68 at mean B1 (B1mean ) of 0.70 µT when using a mean gradient (Gmean ) of 0.25 mT/m. CONCLUSION Either a prescan or a field map can be used to correct for off-resonance effects and retrieve a good brain perfusion signal at 7T. Although the three methods performed well in this study, FMcor may be better suited for patient studies because it accounted for vessel-specific ΔB0 variations. Further improvements in image quality will be possible by optimizing the labeling efficiency with advanced hardware and software while satisfying specific absorption rate constraints.
Collapse
Affiliation(s)
- Gaël Saïb
- NINDS/LFMI, National Institutes of Health, Bethesda, Maryland, USA
| | - Alan P Koretsky
- NINDS/LFMI, National Institutes of Health, Bethesda, Maryland, USA
| | | |
Collapse
|
2
|
Riedinger JM, Gallet M, Nicolas A, Drouet C, Cochet A. [Factors influencing platelets labelling with indium-111 oxine]. Ann Biol Clin (Paris) 2021; 79:339-44. [PMID: 34427559 DOI: 10.1684/abc.2021.1666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Autologous indium-111 labelled platelets can be used for kinetic studies in patients with autoimmune thrombocytopenic purpura [AITP]. The objective of this study was to evaluate some biological and clinical factors influencing the labeling efficiency. METHODS We studied incubation media (Plasma media [MP] or dry media [MS]), platelet concentration [NP], mean platelet volume [VPM], hemoglobin level and pathology associated with AITP. RESULTS This was a retrospective study of 93 platelets labelling (43 in MS and 50 in MP), 38 primary AITP (41%) and 55 secondary AITP (59%). The labeling efficiency was 72% (78% in MS versus 53% in MP; p < 0.0001). The labeling efficiency was correlated with VPM (p = 0.0004), NP (p = 0.03), hemoglobin level (p = 0.037) and type of AITP (p = 0.0036). The incubation medium, hemoglobin level and type of the AITP have an independent predictive value on the labeling efficiency. CONCLUSION These data confirm the influence of the incubation medium on the labeling efficiency and identify two other predictive criteria, hemoglobin level and type of AITP.
Collapse
|
3
|
Abstract
Quantum dots exhibit unique properties compared to other fluorophores, such as bright fluorescence and lack of photobleaching, resulting in their widespread utilization as fluorescent protein labels in the life sciences. However, their application is restricted to relative quantifications due to lacking knowledge about the labeling efficiency. We here present a strategy for determining the labeling efficiency of quantum dot labeling of HER2 in overexpressing breast cancer cells. Correlative light- and liquid-phase electron microscopy of whole cells was used to convert fluorescence intensities into the underlying molecular densities of the quantum dots. The labeling procedure with small affinity proteins was optimized yielding a maximal labeling efficiency of 83%, which was applicable to the high amount of ∼1.5 × 106 HER2 per cell. With the labeling efficiency known, it is now possible to derive the absolute protein expression levels in the plasma membrane and its variation within a cell and between cells.
Collapse
Affiliation(s)
- Diana B Peckys
- Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Cedric Quint
- Department of Physics, Saarland University, 66123 Saarbrücken, Germany
| | - Niels de Jonge
- Department of Physics, Saarland University, 66123 Saarbrücken, Germany
- INM - Leibniz Institute for New Materials, 66123 Saarbrücken, Germany
| |
Collapse
|
4
|
Bladt P, van Osch MJP, Clement P, Achten E, Sijbers J, den Dekker AJ. Supporting measurements or more averages? How to quantify cerebral blood flow most reliably in 5 minutes by arterial spin labeling. Magn Reson Med 2020; 84:2523-2536. [PMID: 32424947 PMCID: PMC7402018 DOI: 10.1002/mrm.28314] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/19/2020] [Accepted: 04/17/2020] [Indexed: 11/29/2022]
Abstract
Purpose To determine whether sacrificing part of the scan time of pseudo‐continuous arterial spin labeling (PCASL) for measurement of the labeling efficiency and blood
T1 is beneficial in terms of CBF quantification reliability. Methods In a simulation framework, 5‐minute scan protocols with different scan time divisions between PCASL data acquisition and supporting measurements were evaluated in terms of CBF estimation variability across both noise and ground truth parameter realizations taken from the general population distribution. The entire simulation experiment was repeated for a single‐post‐labeling delay (PLD), multi‐PLD, and free‐lunch time‐encoded (te‐FL) PCASL acquisition strategy. Furthermore, a real data study was designed for preliminary validation. Results For the considered population statistics, measuring the labeling efficiency and the blood
T1 proved beneficial in terms of CBF estimation variability for any distribution of the 5‐minute scan time compared to only acquiring ASL data. Compared to single‐PLD PCASL without support measurements as recommended in the consensus statement, a 26%, 33%, and 42% reduction in relative CBF estimation variability was found for optimal combinations of supporting measurements with single‐PLD, free‐lunch, and multi‐PLD PCASL data acquisition, respectively. The benefit of taking the individual variation of blood
T1 into account was also demonstrated in the real data experiment. Conclusions Spending time to measure the labeling efficiency and the blood
T1 instead of acquiring more averages of the PCASL data proves to be advisable for robust CBF quantification in the general population.
Collapse
Affiliation(s)
- Piet Bladt
- imec - Vision Lab, Department of Physics, University of Antwerp, Antwerp, Belgium
| | - Matthias J P van Osch
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.,Leiden Institute of Brain and Cognition, Leiden University, Leiden, The Netherlands
| | - Patricia Clement
- Department of Radiology and Nuclear Medicine, Ghent University, Ghent, Belgium
| | - Eric Achten
- Department of Radiology and Nuclear Medicine, Ghent University, Ghent, Belgium
| | - Jan Sijbers
- imec - Vision Lab, Department of Physics, University of Antwerp, Antwerp, Belgium
| | - Arnold J den Dekker
- imec - Vision Lab, Department of Physics, University of Antwerp, Antwerp, Belgium
| |
Collapse
|
5
|
Schollenberger J, Figueroa CA, Nielsen JF, Hernandez-Garcia L. Practical considerations for territorial perfusion mapping in the cerebral circulation using super-selective pseudo-continuous arterial spin labeling. Magn Reson Med 2019; 83:492-504. [PMID: 31418475 DOI: 10.1002/mrm.27936] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 06/18/2019] [Accepted: 07/17/2019] [Indexed: 12/29/2022]
Abstract
PURPOSE This paper discusses several challenges faced by super-selective pseudo-continuous arterial spin labeling, which is used to quantify territorial perfusion in the cerebral circulation. The effects of off-resonance, pulsatility, vessel movement, and label rotation scheme are investigated, and methods to maximize labeling efficiency and overall image quality are evaluated. A strategy to calculate the territorial perfusion fractions of individual vessels is proposed. METHODS The effects of off-resonance, label rotation scheme, and vessel movement on labeling efficiency were simulated. Two off-resonance compensation strategies (multiphase prescan, field map), cardiac triggering, and vessel movement were studied in vivo in a group of 10 subjects. Subsequently, a territorial perfusion fraction map was acquired in 2 subjects based on the mean vessel labeling efficiency. RESULTS Multiphase calibration provided the highest labeling efficiency (P = .002) followed by the field map compensation (P = .037) compared with the uncompensated acquisition. Cardiac triggering resulted in a qualitative improvement of the image and an increase in signal contrast between the perfusion territory and the surrounding tissue (P = .010) but failed to show a significant change in temporal and spatial SNR. The constant clockwise label rotation scheme yielded the highest labeling efficiency. Significant vessel movement (>2 mm according to simulations) was observed in 50% of subjects. The measured territorial perfusion fractions showed good agreement with anatomical data. CONCLUSION Optimized labeling efficiency resulted in increased image quality and accuracy of territorial perfusion fraction maps. Labeling efficiency depends critically on off-resonance calibration, cardiac triggering, optimal label rotation scheme, and vessel location tracking.
Collapse
Affiliation(s)
- Jonas Schollenberger
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
| | - C Alberto Figueroa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.,Department of Surgery, University of Michigan, Ann Arbor, Michigan
| | - Jon-Fredrik Nielsen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.,FMRI Laboratory, University of Michigan, Ann Arbor, Michigan
| | - Luis Hernandez-Garcia
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.,FMRI Laboratory, University of Michigan, Ann Arbor, Michigan
| |
Collapse
|
6
|
Han G, Chen SY, Gonzalez VD, Zunder ER, Fantl WJ, Nolan GP. Atomic mass tag of bismuth-209 for increasing the immunoassay multiplexing capacity of mass cytometry. Cytometry A 2017; 91:1150-1163. [PMID: 29205767 DOI: 10.1002/cyto.a.23283] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/25/2017] [Accepted: 10/25/2017] [Indexed: 01/28/2023]
Abstract
Mass cytometry (or CyTOF) is an atomic mass spectrometry-based single-cell immunoassay technology, which has provided an increasingly systematic and sophisticated view in basic biological and clinical studies. Using elemental reporters composed of stable heavy metal isotopes, more than 50 cellular parameters are measured simultaneously. However, this current multiplexing does not meet the theoretical capability of CyTOF instrumentation with 135 detectable channels, primarily due to the limitation of available chemistries for conjugating elemental mass tags to affinity reagents. To address this issue, we develop herein additional metallic mass tag based on bismuth-209 (209 Bi) for efficient conjugation to monoclonal antibody. This enables the use of an addtional channel m/z = 209 of CyTOF for single-cell immunoassays. Bismuth has nearly the same charge-to-radius ratio as lanthanide elements; thus, bismuth(III) cations (209 Bi3+ ) could coordinate with DTPA chelators in the same geometry of O- and N-donor groups as that of lanthanide. In this report, the coordination chemistry of 209 Bi3+ with DTPA chelators and Maxpar® X8 polymers were investigated in details. Accordingly, the protocols of conjugating antibody with bismuth mass tag were provided. A method based on UV-Vis absorbance at 280 nm of 209 Bi3+ -labeling DTPA complexes was developed to evaluate the stoichiometric ratio of 209 Bi3+ cations to the conjugated antibody. Side-by-side single-cell analysis experiments with bismuth- and lanthanide-tagged antibodies were carried out to compare the analytical sensitivities. The measurement accuracy of bismuth-tagged antibody was validated within in vitro assay using primary human natural killer cells. Furthermore, bismuth-tagged antibodies were successfully employed in cell cycle measurements and high-dimensional phenotyping immunoassays. © 2017 International Society for Advancement of Cytometry.
Collapse
Affiliation(s)
- Guojun Han
- Baxter Laboratory for Stem Cell Biology Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford California
| | - Shih-Yu Chen
- Baxter Laboratory for Stem Cell Biology Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford California
| | - Veronica D Gonzalez
- Baxter Laboratory for Stem Cell Biology Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford California
| | - Eli R Zunder
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Wendy J Fantl
- Stanford Comprehensive Cancer Institute and Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford California
| | - Garry P Nolan
- Baxter Laboratory for Stem Cell Biology Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford California
| |
Collapse
|
7
|
Zhao L, Vidorreta M, Soman S, Detre JA, Alsop DC. Improving the robustness of pseudo-continuous arterial spin labeling to off-resonance and pulsatile flow velocity. Magn Reson Med 2017; 78:1342-1351. [PMID: 27774656 PMCID: PMC5848499 DOI: 10.1002/mrm.26513] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/01/2016] [Accepted: 09/26/2016] [Indexed: 01/22/2023]
Abstract
PURPOSE To improve pseudo-continuous arterial spin labeling (PCASL) robustness to off-resonance and pulsatile blood flow velocity. METHODS Bloch equations were solved to evaluate the effect of labeling parameters in a pulsatile flow model for a range of off-resonance. Experimental confirmation was achieved in volunteers using linear phase increase between labeling pulses to approximate off-resonance errors. We first assessed the location of the labeling plane in four volunteers. Next, we explored a range of parameters-including balanced and unbalanced gradients-in five more volunteers at an optimal labeling plane location. RESULTS Simulations demonstrated that 1) high velocities are vulnerable to off-resonance, 2) unbalanced PCASL outperforms balanced PCASL, 3) increased B1 and low average gradient improve the labeling efficiency for high-velocity flow, and 4) a low ratio of selective to average gradient improves off-resonance robustness. A good agreement between theory and experiment was observed. CONCLUSION The robustness of PCASL can be increased by selecting an unbalanced scheme with a low average gradient (0.5 mT/m), a low ratio (7×) of selective to average gradients, and the highest feasible B1 (1.8 μT). Placing the labeling plane above the carotid bifurcation and below the V3 segment, usually between the second and third vertebrae, yielded robust results. Magn Reson Med 78:1342-1351, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Li Zhao
- Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - Marta Vidorreta
- Department of Radiology, University of Pennsylvania, Philadelphia, PA
- Department of Neurology, University of Pennsylvania, Philadelphia, PA
| | - Salil Soman
- Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - John A. Detre
- Department of Radiology, University of Pennsylvania, Philadelphia, PA
- Department of Neurology, University of Pennsylvania, Philadelphia, PA
| | - David C. Alsop
- Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| |
Collapse
|
8
|
Pedrosa de Barros N, McKinley R, Wiest R, Slotboom J. Improving labeling efficiency in automatic quality control of MRSI data. Magn Reson Med 2017; 78:2399-2405. [PMID: 28169457 DOI: 10.1002/mrm.26618] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 12/05/2016] [Accepted: 12/29/2016] [Indexed: 11/10/2022]
Abstract
PURPOSE To improve the efficiency of the labeling task in automatic quality control of MR spectroscopy imaging data. METHODS 28'432 short and long echo time (TE) spectra (1.5 tesla; point resolved spectroscopy (PRESS); repetition time (TR)= 1,500 ms) from 18 different brain tumor patients were labeled by two experts as either accept or reject, depending on their quality. For each spectrum, 47 signal features were extracted. The data was then used to run several simulations and test an active learning approach using uncertainty sampling. The performance of the classifiers was evaluated as a function of the number of patients in the training set, number of spectra in the training set, and a parameter α used to control the level of classification uncertainty required for a new spectrum to be selected for labeling. RESULTS The results showed that the proposed strategy allows reductions of up to 72.97% for short TE and 62.09% for long TE in the amount of data that needs to be labeled, without significant impact in classification accuracy. Further reductions are possible with significant but minimal impact in performance. CONCLUSION Active learning using uncertainty sampling is an effective way to increase the labeling efficiency for training automatic quality control classifiers. Magn Reson Med 78:2399-2405, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Nuno Pedrosa de Barros
- Support Center for Advanced Neuroimaging, Inselspital, Bern, Switzerland.,University of Bern, Bern, Switzerland
| | - Richard McKinley
- Support Center for Advanced Neuroimaging, Inselspital, Bern, Switzerland.,University of Bern, Bern, Switzerland
| | - Roland Wiest
- Support Center for Advanced Neuroimaging, Inselspital, Bern, Switzerland.,University of Bern, Bern, Switzerland
| | - Johannes Slotboom
- Support Center for Advanced Neuroimaging, Inselspital, Bern, Switzerland.,University of Bern, Bern, Switzerland
| |
Collapse
|
9
|
Dolui S, Wang Z, Wang DJJ, Mattay R, Finkel M, Elliott M, Desiderio L, Inglis B, Mueller B, Stafford RB, Launer LJ, Jacobs DR, Bryan RN, Detre JA. Comparison of non-invasive MRI measurements of cerebral blood flow in a large multisite cohort. J Cereb Blood Flow Metab 2016; 36:1244-56. [PMID: 27142868 PMCID: PMC4929707 DOI: 10.1177/0271678x16646124] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/22/2016] [Indexed: 11/16/2022]
Abstract
UNLABELLED Arterial spin labeling and phase contrast magnetic resonance imaging provide independent non-invasive methods for measuring cerebral blood flow. We compared global cerebral blood flow measurements obtained using pseudo-continuous arterial spin labeling and phase contrast in 436 middle-aged subjects acquired at two sites in the NHLBI CARDIA multisite study. Cerebral blood flow measured by phase contrast (CBFPC: 55.76 ± 12.05 ml/100 g/min) was systematically higher (p < 0.001) and more variable than cerebral blood flow measured by pseudo-continuous arterial spin labeling (CBFPCASL: 47.70 ± 9.75). The correlation between global cerebral blood flow values obtained from the two modalities was 0.59 (p < 0.001), explaining less than half of the observed variance in cerebral blood flow estimates. Well-established correlations of global cerebral blood flow with age and sex were similarly observed in both CBFPCASL and CBFPC CBFPC also demonstrated statistically significant site differences, whereas no such differences were observed in CBFPCASL No consistent velocity-dependent effects on pseudo-continuous arterial spin labeling were observed, suggesting that pseudo-continuous labeling efficiency does not vary substantially across typical adult carotid and vertebral velocities, as has previously been suggested. CONCLUSIONS Although CBFPCASL and CBFPC values show substantial similarity across the entire cohort, these data do not support calibration of CBFPCASL using CBFPC in individual subjects. The wide-ranging cerebral blood flow values obtained by both methods suggest that cerebral blood flow values are highly variable in the general population.
Collapse
Affiliation(s)
- Sudipto Dolui
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA
| | - Ze Wang
- Center for Cognition and Brain Disorders and the Affiliated Hospital, Hangzhou Normal University, Hangzhou, China Departments of Psychiatry and Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Danny J J Wang
- Department of Neurology, University of California, Los Angeles, CA, USA
| | - Raghav Mattay
- Raymond and Ruth Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mack Finkel
- School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Mark Elliott
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Lisa Desiderio
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ben Inglis
- Henry H. Wheeler Jr. Brain Imaging Center, University of California, Berkeley, CA, USA
| | - Bryon Mueller
- Department of Psychiatry, University of Minnesota, Minneapolis, MN, USA
| | - Randall B Stafford
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - Lenore J Launer
- Laboratory of Epidemiology and Population Science, National Institute on Aging, Bethesda, MD, USA
| | - David R Jacobs
- Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN, USA
| | - R Nick Bryan
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - John A Detre
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
10
|
Englund EK, Rodgers ZB, Langham MC, Mohler ER, Floyd TF, Wehrli FW. Measurement of skeletal muscle perfusion dynamics with pseudo-continuous arterial spin labeling (pCASL): Assessment of relative labeling efficiency at rest and during hyperemia, and comparison to pulsed arterial spin labeling (PASL). J Magn Reson Imaging 2016; 44:929-39. [PMID: 27043039 DOI: 10.1002/jmri.25247] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/04/2016] [Indexed: 12/21/2022] Open
Abstract
PURPOSE To compare calf skeletal muscle perfusion measured with pulsed arterial spin labeling (PASL) and pseudo-continuous arterial spin labeling (pCASL) methods, and to assess the variability of pCASL labeling efficiency in the popliteal artery throughout an ischemia-reperfusion paradigm. MATERIALS AND METHODS At 3T, relative pCASL labeling efficiency was experimentally assessed in five subjects by measuring the signal intensity of blood in the popliteal artery just distal to the labeling plane immediately following pCASL labeling or control preparation pulses, or without any preparation pulses throughout separate ischemia-reperfusion paradigms. The relative label and control efficiencies were determined during baseline, hyperemia, and recovery. In a separate cohort of 10 subjects, pCASL and PASL sequences were used to measure reactive hyperemia perfusion dynamics. RESULTS Calculated pCASL labeling and control efficiencies did not differ significantly between baseline and hyperemia or between hyperemia and recovery periods. Relative to the average baseline, pCASL label efficiency was 2 ± 9% lower during hyperemia. Perfusion dynamics measured with pCASL and PASL did not differ significantly (P > 0.05). Average leg muscle peak perfusion was 47 ± 20 mL/min/100g or 50 ± 12 mL/min/100g, and time to peak perfusion was 25 ± 3 seconds and 25 ± 7 seconds from pCASL and PASL data, respectively. Differences of further metrics parameterizing the perfusion time course were not significant between pCASL and PASL measurements (P > 0.05). CONCLUSION No change in pCASL labeling efficiency was detected despite the almost 10-fold increase in average blood flow velocity in the popliteal artery. pCASL and PASL provide precise and consistent measurement of skeletal muscle reactive hyperemia perfusion dynamics. J. MAGN. RESON. IMAGING 2016;44:929-939.
Collapse
Affiliation(s)
- Erin K Englund
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
| | - Zachary B Rodgers
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael C Langham
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Emile R Mohler
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Thomas F Floyd
- Department of Anesthesiology, Stony Brook University, Stony Brook, New York, USA
| | - Felix W Wehrli
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| |
Collapse
|