1
|
Lopez Kolkovsky AL, Carlier PG, Marty B, Meyerspeer M. Interleaved and simultaneous multi-nuclear magnetic resonance in vivo. Review of principles, applications and potential. NMR IN BIOMEDICINE 2022; 35:e4735. [PMID: 35352440 PMCID: PMC9542607 DOI: 10.1002/nbm.4735] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/03/2022] [Accepted: 03/28/2022] [Indexed: 06/14/2023]
Abstract
Magnetic resonance signals from different nuclei can be excited or received at the same time,rendering simultaneous or rapidly interleaved multi-nuclear acquisitions feasible. The advan-tages are a reduction of total scan time compared to sequential multi-nuclear acquisitions or that additional information from heteronuclear data is obtained at thesame time and anatomical position. Information content can be qualitatively increased by delivering a more comprehensive MR-based picture of a transient state (such as an exercise bout). Also, combiningnon-proton MR acquisitions with 1 Hinformation (e.g., dynamic shim updates and motion correction) can be used to improve data quality during long scans and benefits image coregistration. This work reviews the literature on interleaved and simultaneous multi-nuclear MRI and MRS in vivo. Prominent use cases for this methodology in clinical and research applications are brain and muscle, but studies have also been carried out in other targets, including the lung, knee, breast and heart. Simultaneous multi-nuclear measurements in the liver and kidney have also been performed, but exclusively in rodents. In this review, a consistent nomenclature is proposed, to help clarify the terminology used for this principle throughout the literature on in-vivo MR. An overview covers the basic principles, the technical requirements on the MR scanner and the implementations realised either by MR system vendors or research groups, from the early days until today. Considerations regarding the multi-tuned RF coils required and heteronuclear polarisation interactions are briefly discussed, and fields for future in-vivo applications for interleaved multi-nuclear MR pulse sequences are identified.
Collapse
Affiliation(s)
- Alfredo L. Lopez Kolkovsky
- NMR Laboratory, Neuromuscular Investigation CenterInstitute of MyologyParisFrance
- NMR laboratoryCEA, DRF, IBFJParisFrance
| | - Pierre G. Carlier
- NMR Laboratory, Neuromuscular Investigation CenterInstitute of MyologyParisFrance
- NMR laboratoryCEA, DRF, IBFJParisFrance
| | - Benjamin Marty
- NMR Laboratory, Neuromuscular Investigation CenterInstitute of MyologyParisFrance
- NMR laboratoryCEA, DRF, IBFJParisFrance
| | - Martin Meyerspeer
- High‐Field MR Center, Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| |
Collapse
|
2
|
Jeong KE, Lee SY, Yeom SK, Carlson N, Shah LM, Rose J, Jeong EK. Ultrahigh-b diffusion-weighted imaging for quantitative evaluation of myelination in shiverer mouse spinal cord. Magn Reson Med 2021; 87:179-192. [PMID: 34418157 DOI: 10.1002/mrm.28978] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/22/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022]
Abstract
PURPOSE To perform a quantitative evaluation of myelination on WT and myelin-deficient (shiverer) mouse spinal cords using ultrahigh-b diffusion-weighted imaging (UHb-DWI). METHODS UHb-DWI of ex vivo on spinal cord specimens of two shiverer (C3HeB/FeJ-shiverer, homozygous genotype for MbPshi ) and six WT (Black Six, C3HeB/FeJ) mice were acquired using 3D multishot diffusion-weighted stimulated-echo EPI, a homemade RF coil, and a small-bore 7T MRI system. Imaging was performed in transaxial plane with 75 × 75 μm2 in-plane resolution, 1-mm-slice thickness, and radial DWI using bmax = 42,890 s/mm2 . Histological evaluation was performed on upper thoracic sections using optical and transmission electron microscopy. Numerical Monte Carlo simulations (MCSs) of water diffusion were performed to facilitate interpretation of UHb-DWI signal-b curves. RESULTS The white matter ultrahigh-b radial DWI (UHb-rDWI) signal-b curves of WT mouse cords behaved biexponentially with high-b diffusion coefficient DH < 0.020 × 10-3 mm2 /s. However, as expected with less myelination, the signal-b of shiverer mouse cords behaved monoexponentially with significantly greater DH = 0.162 × 10-3 , 0.142 × 10-3 , and 0.164 × 10-3 mm2 /s at anterodorsal, posterodorsal, and lateral columns, respectively. The axial DWI signals of all mouse cords behaved monoexponentially with D = (0.718-1.124) × 10-3 mm2 /s. MCS suggests that these elevated DH are mainly induced by increased water exchange at the myelin sheath. Microscopic results were consistent with the UHb-rDWI findings. CONCLUSION UHb-DWI provides quantitative differences in myelination of spinal cords from myelin-deficit shiverer and WT mice. UHb-DWI may become a powerful tool to evaluate myelination in demyelinating disease models that may translate to human diseases, including multiple sclerosis.
Collapse
Affiliation(s)
- Kyle E Jeong
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Sophie YouJung Lee
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Suk-Keu Yeom
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA.,Korea University Ansan Medical Center, Ansan, Korea
| | - Noel Carlson
- Neuroimmunology Division, University of Utah, Salt Lake City, Utah, USA.,Neurobiology, University of Utah, Salt Lake City, Utah, USA.,GRECC, VA Salt Lake City Healthcare System, Salt Lake City, Utah, USA.,Neurovirology Research Laboratory, VA Salt Lake City Healthcare System, Salt Lake City, Utah, USA
| | - Lubdha M Shah
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA
| | - John Rose
- Neuroimmunology Division, University of Utah, Salt Lake City, Utah, USA.,Neurovirology Research Laboratory, VA Salt Lake City Healthcare System, Salt Lake City, Utah, USA
| | - Eun-Kee Jeong
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA.,Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA
| |
Collapse
|
3
|
Jeong K, Shah LM, Lee YJ, Thapa B, Sapkota N, Bisson E, Carlson NG, Jeong EK, Rose JW. High-b diffusivity of MS lesions in cervical spinal cord using ultrahigh-b DWI (UHb-DWI). Neuroimage Clin 2021; 30:102610. [PMID: 33752076 PMCID: PMC7985401 DOI: 10.1016/j.nicl.2021.102610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 02/11/2021] [Accepted: 02/18/2021] [Indexed: 12/27/2022]
Abstract
PURPOSE The purpose of this study was to investigate UHb-rDWI signal in white matter tracts of the cervical spinal cord (CSC) and compare quantitative values between healthy control WM with both MS NAWM and MS WM lesions. METHODS UHb-rDWI experiments were performed on (a) 7 MS patients with recently active or chronic lesions in CSC and on (b) 7 healthy control of similar age range and gender distribution to MS subjects. All MRI data were acquired using clinical 3T MRI system. Axial high-b diffusion images were acquired using 2D single-shot DW stimulated EPI with reduced FOV and a CSC-dedicated 8 channel array coil. High-b diffusion coefficient DH was estimated by fitting the signal-b curve to a double or single-exponential function. RESULTS The high-b diffusivity DH values were measured as (0.767 ± 0.297) × 10-3 mm2/s in the posterior column lesions, averaged over 6 MS patients, and 0.587 × 10-3 mm2/s in the corticospinal tract for another patient. The averaged DH values of the 7 healthy volunteers from the posterior and lateral column were (0.0312 ± 0.0306) × 10-3 and (0.0505 ± 0.0205) × 10-3 mm2/s, respectively. UHb-rDWI signal-b curves of the MS patients revealed to noticeably behave differently to that of the healthy controls. The patient signal-b curves decayed with greater high-b decay constants to reach lower signal intensities relative to signal-b curves of the healthy controls. CONCLUSION UHb-DWI of the CSC reveals a marked difference in signal-b-curves and DH values in MS lesions compared to NAWM and healthy control WM. Based on physical principles, we interpret these altered observations of quantitative diffusion values to be indicative of demyelination. Further studies in animal models will be required to fully interpret UHb-DWI quantitative diffusion values during demyelination and remyelination.
Collapse
Affiliation(s)
- Kyle Jeong
- Utah Center for Advanced Imaging Research, University of Utah, Utah, USA
| | - Lubdha M Shah
- Department of Radiology and Imaging Sciences, University of Utah, Utah, USA
| | - You-Jung Lee
- Utah Center for Advanced Imaging Research, University of Utah, Utah, USA
| | - Bijaya Thapa
- Utah Center for Advanced Imaging Research, University of Utah, Utah, USA
| | - Nabraj Sapkota
- Utah Center for Advanced Imaging Research, University of Utah, Utah, USA
| | - Erica Bisson
- Department of Neurosurgery, University of Utah, Utah, USA
| | - Noel G Carlson
- Neuroimmunology and Neurovirology Division, Department of Neurology, University of Utah, Utah, USA; GRECC, VA Salt Lake City Health Care System, Utah, USA; Department of Neurobiology, University of Utah, Utah, USA
| | - E K Jeong
- Utah Center for Advanced Imaging Research, University of Utah, Utah, USA; Department of Radiology and Imaging Sciences, University of Utah, Utah, USA
| | - John W Rose
- Neuroimmunology and Neurovirology Division, Department of Neurology, University of Utah, Utah, USA; Neurology Service, VA Salt Lake City Health Care System, Utah, USA.
| |
Collapse
|
4
|
Lopez Kolkovsky AL, Marty B, Giacomini E, Meyerspeer M, Carlier PG. Repeatability of multinuclear interleaved acquisitions with nuclear Overhauser enhancement effect in dynamic experiments in the calf muscle at 3T. Magn Reson Med 2021; 86:115-130. [PMID: 33565187 DOI: 10.1002/mrm.28684] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/23/2020] [Accepted: 12/23/2020] [Indexed: 02/01/2023]
Abstract
PURPOSE To evaluate the repeatability of multinuclear interleaved 1 H/31 P NMR dynamic acquisitions in skeletal muscle and the impact of nuclear Overhauser enhancement (nOe) on the 31 P results at 3T in exercise-recovery and ischemia-hyperemia paradigms. METHODS A 1 H/31 P interleaved pulse sequence was used to measure every 2.5 s a perfusion-weighted image, a T 2 ∗ map, a 31 P spectrum and 32 1 H spectra sensitive to deoxymyoglobin. 21 subjects performed a plantar flexion exercise and after recovery underwent an 8-min lower leg ischemia. The procedure was repeated in visit 2 with 12 subjects. An additional exercise bout without 1 H excitation was appended to visit 1. Individual 1 H RF pulse nOe was measured at rest in every visit. RESULTS Repeatability scores (coefficient of variation, Bland-Altman analysis) were similar to those found in the literature using similar mono-nuclear acquisitions. |Pi]/[PCr], pH drop, creatine rephosphorylation rate (τPCr ), maximum perfusion, time to peak perfusion, and blood flow post-exercise showed high reliability (intraclass correlation coefficient > 0.7), whereas hemodynamic results from reactive hyperemia showed higher repeatability. After accounting for nOe, which increased Pi and PCr signal-to-noise ratio by 30%, no differences in 31 P results were observed between interleaved and 31 P MRS-only acquisitions. τPCr was unaffected by nOe. CONCLUSION The method shows good repeatability for both paradigms while simultaneously providing multiple dynamic data sets on a clinical scanner. The nOe effects were accounted for on a per-subject and per-visit basis using a short 31 P reference scan. This multiparametric approach has a multitude of applications for the study of oxygen utilization and ATP turnover in the muscle.
Collapse
Affiliation(s)
- Alfredo L Lopez Kolkovsky
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France.,NMR Laboratory, CEA, DRF, IBFJ, MIRCen, Paris, France
| | - Benjamin Marty
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France.,NMR Laboratory, CEA, DRF, IBFJ, MIRCen, Paris, France
| | - Eric Giacomini
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France
| | - Martin Meyerspeer
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Pierre G Carlier
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France.,NMR Laboratory, CEA, DRF, IBFJ, MIRCen, Paris, France
| |
Collapse
|
5
|
Caterini JE, Elzibak AH, St Michel EJ, McCrindle BW, Redington AN, Thompson S, Noseworthy MD, Wells GD. Characterizing blood oxygen level-dependent (BOLD) response following in-magnet quadriceps exercise. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2014; 28:271-8. [PMID: 25248947 DOI: 10.1007/s10334-014-0461-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 08/11/2014] [Accepted: 09/09/2014] [Indexed: 11/29/2022]
|
6
|
Skeletal muscle perfusion and oxygenation assessed by dynamic NMR imaging and spectroscopy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 701:341-6. [PMID: 21445807 DOI: 10.1007/978-1-4419-7756-4_46] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Muscle perfusion, and capillary and intramyocytic oxygenation can be probed non-invasively in vivo by functional NMR techniques, arterial spin labelling combined with imaging, BOLD imaging and deoxymyoglobin (1)H spectroscopy, respectively. After adequate adaptation of equipment, these measurements can be performed in parallel, together with (31)P spectroscopy and provide a comprehensive analysis of various facets of oxygen metabolism in dynamic protocols, in humans as well as in animal models.
Collapse
|
7
|
Baligand C, Wary C, Ménard JC, Giacomini E, Hogrel JY, Carlier PG. Measuring perfusion and bioenergetics simultaneously in mouse skeletal muscle: a multiparametric functional-NMR approach. NMR IN BIOMEDICINE 2011; 24:281-290. [PMID: 20862659 DOI: 10.1002/nbm.1587] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 06/12/2010] [Accepted: 06/15/2010] [Indexed: 05/29/2023]
Abstract
A totally noninvasive set-up was developed for comprehensive NMR evaluation of mouse skeletal muscle function in vivo. Dynamic pulsed arterial spin labeling-NMRI perfusion and blood oxygenation level-dependent (BOLD) signal measurements were interleaved with (31)P NMRS to measure both vascular response and oxidative capacities during stimulated exercise and subsequent recovery. Force output was recorded with a dedicated ergometer. Twelve exercise bouts were performed. The perfusion, BOLD signal, pH and force-time integral were obtained from mouse legs for each exercise. All reached a steady state after the second exercise, justifying the pointwise summation of the last 10 exercises to compensate for the limited (31)P signal. In this way, a high temporal resolution of 2.5 s was achieved to provide a time constant for phosphocreatine (PCr) recovery (τ(PCr)). The higher signal-to-noise ratio improved the precision of τ(PCr) measurement [coefficient of variation (CV) = 16.5% vs CV = 49.2% for a single exercise at a resolution of 30 s]. Inter-animal summation confirmed that τ(PCr) was stable at steady state, but shorter (89.3 ± 8.6 s) than after the first exercise (148 s, p < 0.05). This novel experimental approach provides an assessment of muscle vascular response simultaneously to energetic function in vivo. Its pertinence was illustrated by observing the establishment of a metabolic steady state. This comprehensive tool offers new perspectives for the study of muscle pathology in mice models.
Collapse
Affiliation(s)
- C Baligand
- Institute of Myology, NMR Laboratory, Paris, France
| | | | | | | | | | | |
Collapse
|
8
|
Wray DW, Nishiyama SK, Monnet A, Wary C, Duteil SS, Carlier PG, Richardson RS. Antioxidants and aging: NMR-based evidence of improved skeletal muscle perfusion and energetics. Am J Physiol Heart Circ Physiol 2009; 297:H1870-5. [PMID: 19767527 DOI: 10.1152/ajpheart.00709.2009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We sought to examine the potential role of oxidative stress on skeletal muscle function with advancing age. Nuclear magnetic resonance (NMR) was employed to simultaneously assess muscle perfusion (arterial spin labeling) and energetics ((31)P NMR spectroscopy) in the lower leg of young (26 + or - 5 yr, n = 6) and older (70 + or - 5 yr, n = 6) healthy volunteers following the consumption of either placebo (PL) or an oral antioxidant (AO) cocktail (vitamins C and E and alpha-lipoic acid), previously documented to decrease plasma free radical concentration. NMR measurements were made during and after 5 min of moderate intensity (approximately 5 W) plantar flexion exercise. AO administration significantly improved end-exercise perfusion (AO, 50 + or - 5, and PL, 43 + or - 4 ml x 100 g(-1) x min(-1)) and postexercise perfusion area under the curve (AO, 1,286 + or - 236, and PL, 866 + or - 144 ml/100 g) in older subjects, whereas AO administration did not alter hemodynamics in the young group. Concomitantly, muscle oxidative capacity (time constant of phosphocreatine recovery, tau) was improved following AO in the older (AO, 43 + or - 1, and PL, 51 + or - 7 s) but not the young (AO, 54 + or - 5, and PL, 48 + or - 7 s) group. These findings support the concept that oxidative stress may be partially responsible for the age-related decline in skeletal muscle perfusion during physical activity and reveal a muscle metabolic reserve capacity in the elderly that is accessible under conditions of improved perfusion.
Collapse
Affiliation(s)
- D Walter Wray
- Department of Medicine, University of California San Diego, La Jolla, CA, USA.
| | | | | | | | | | | | | |
Collapse
|
9
|
Wray DW, Nishiyama SK, Monnet A, Wary C, Duteil S, Carlier PG, Richardson RS. Multiparametric NMR-based assessment of skeletal muscle perfusion and metabolism during exercise in elderly persons: preliminary findings. J Gerontol A Biol Sci Med Sci 2009; 64:968-74. [PMID: 19377015 DOI: 10.1093/gerona/glp044] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
BACKGROUND Aging is associated with a decline in exercise capacity that may be attributable to maladaptations in both skeletal muscle perfusion and metabolism; yet very little is known regarding the real-time, within-muscle interplay between these parameters during physical activity. Therefore, we utilized an unique nuclear magnetic resonance sequence to concomitantly examine changes in lower leg skeletal muscle perfusion and metabolism. METHODS In young (26+/-5 years, n=6) and older (70+/-5 years, n=6) healthy volunteers, arterial spin labeling measurements of muscle perfusion were combined with 31 Phosphorous (31P) nuclear magnetic resonance spectroscopy to monitor high-energy phosphate metabolites during and after 5 minutes of moderate-intensity (approximately 5W) plantar flexion exercise. RESULTS Compared with young, end-exercise perfusion was diminished in older participants (43+/-10 mL/100 g/minute, old; 60+/-7 mL/100 g.minute, young), accompanied by greater phosphocreatine (PCr) depletion (-28%+/-12%, old; -19%+/-7%, young) and elevated inorganic phosphate/PCr (0.41+/-0.2, old; 0.24+/-0.09, young); yet the time constant for PCr recovery (tau, an index of muscle oxidative capacity) was similar between groups (51+/-17 seconds, old; 48+/-7 seconds, young). CONCLUSIONS Together, these preliminary data provide evidence of an age-related decline in tissue perfusion and increased "metabolic stress" during exercise but demonstrate that overall oxidative capacity in the elderly does not appear negatively affected by this relatively hypoperfused state.
Collapse
Affiliation(s)
- D Walter Wray
- Department of Internal Medicine, University of California San Diego, La Jolla, CA, USA.
| | | | | | | | | | | | | |
Collapse
|
10
|
Carlier PG, Bertoldi D, Baligand C, Wary C, Fromes Y. Muscle blood flow and oxygenation measured by NMR imaging and spectroscopy. NMR IN BIOMEDICINE 2006; 19:954-67. [PMID: 17075963 DOI: 10.1002/nbm.1081] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Tissue perfusion and oxygenation in many organs can be evaluated by various NMR techniques. This review focuses on the specificities, limitations and adaptations of the NMR tools available to investigate perfusion and oxygenation in the skeletal muscle of humans and animal models. A description of how they may be used simultaneously is provided as well. 1H NMR spectroscopy of myoglobin (Mb) monitors intramyocytic oxygenation. It measures the level of deoxy-Mb, from which Mb concentration, Mb desaturation/resaturation rates, muscle oxygenation changes and intracellular partial oxygen pressure (pO2) can be calculated. Positive and negative blood oxygen level-dependent (BOLD) contrasts exist in skeletal muscle. BOLD contrasts primarily reflect changes in capillary-venous oxygenation, but are also directly or indirectly dependent on muscle blood volume, perfusion, vascular network architecture and angulation, relative to the main magnetic field. Arterial spin labelling (ASL) techniques, having high spatial and temporal resolution, are the methods of choice to quantify and map skeletal muscle perfusion non-invasively. Limitations of ASL are poor contrast-to-noise ratio and sensitivity to movement; however, with the introduction of specific adaptations, it has been proven possible to measure skeletal muscle perfusion at both rest and during exercise. The possibility of combining these NMR measurements with others into a single dynamic protocol is most interesting. The 'multiparametric functional (mpf) NMR' concept can be extended to include the evaluation of muscle energy metabolism simultaneously with 31P NMR or with lactate double quantum filtered 1H NMR spectroscopy, an approach which would make NMR an exceptional tool for non-invasive investigations of integrative physiology and biochemistry in skeletal muscle in vivo.
Collapse
Affiliation(s)
- P G Carlier
- NMR Laboratory, AFM and CEA, Pitié-Salpêtrière University Hospital, 75013 Paris, France
| | | | | | | | | |
Collapse
|
11
|
Frouin F, Duteil S, Lesage D, Carlier PG, Herment A, Leroy-Willig A. An automated image-processing strategy to analyze dynamic arterial spin labeling perfusion studies. Application to human skeletal muscle under stress. Magn Reson Imaging 2006; 24:941-51. [PMID: 16916711 DOI: 10.1016/j.mri.2005.09.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Revised: 09/23/2005] [Accepted: 09/23/2005] [Indexed: 11/18/2022]
Abstract
Arterial spin labeling (ASL) perfusion measurements allow the follow-up of muscle perfusion with high temporal resolution during a stress test. Automated image processing is proposed to estimate perfusion maps from ASL images. It is based on two successive analyses: at first, automated rejection of the image pairs between which a large displacement is detected is performed, followed by factor analysis of the dynamic data and cluster analysis to classify pixels with large signal variation characteristic of vessels. Then, after masking these "vascular" pixels, factor analysis and cluster analysis are further applied to separate the different muscles between low or high perfusion increase, yielding a functional map of the leg. Data from 10 subjects (five normal volunteers and five elite sportsmen) had been analyzed. Resulting time perfusion curves from a region of interest (ROI) in active muscles show a good accordance whether extracted with automated processing or with manual processing. This method of functional segmentation allows automated suppression of vessels and fast visualization of muscles with high, medium or low perfusion, without any a priori knowledge.
Collapse
|
12
|
Laher I, Mulvany M, Henrion D. Meeting report: highlights of the 8th International Symposium on Resistance Arteries. Am J Physiol Heart Circ Physiol 2005; 288:H1000-3. [PMID: 15706035 DOI: 10.1152/ajpheart.00832.2004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Ismail Laher
- Dept. of Pharmacology and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada.
| | | | | |
Collapse
|