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Callegari S, Feher A, Smolderen KG, Mena-Hurtado C, Sinusas AJ. Multi-modality imaging for assessment of the microcirculation in peripheral artery disease: Bench to clinical practice. AMERICAN HEART JOURNAL PLUS : CARDIOLOGY RESEARCH AND PRACTICE 2024; 42:100400. [PMID: 38779485 PMCID: PMC11108852 DOI: 10.1016/j.ahjo.2024.100400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 05/07/2024] [Indexed: 05/25/2024]
Abstract
Peripheral artery disease (PAD) is a highly prevalent disorder with a high risk of mortality and amputation despite the introduction of novel medical and procedural treatments. Microvascular disease (MVD) is common among patients with PAD, and despite the established role as a predictor of amputations and mortality, MVD is not routinely assessed as part of current standard practice. Recent pre-clinical and clinical perfusion and molecular imaging studies have confirmed the important role of MVD in the pathogenesis and outcomes of PAD. The recent advancements in the imaging of the peripheral microcirculation could lead to a better understanding of the pathophysiology of PAD, and result in improved risk stratification, and our evaluation of response to therapies. In this review, we will discuss the current understanding of the anatomy and physiology of peripheral microcirculation, and the role of imaging for assessment of perfusion in PAD, and the latest advancements in molecular imaging. By highlighting the latest advancements in multi-modality imaging of the peripheral microcirculation, we aim to underscore the most promising imaging approaches and highlight potential research opportunities, with the goal of translating these approaches for improved and personalized management of PAD in the future.
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Affiliation(s)
- Santiago Callegari
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, USA
- Vascular Medicine Outcomes Program, Yale University, New Haven, CT, USA
| | - Attila Feher
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, USA
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Kim G. Smolderen
- Vascular Medicine Outcomes Program, Yale University, New Haven, CT, USA
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Carlos Mena-Hurtado
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, USA
- Vascular Medicine Outcomes Program, Yale University, New Haven, CT, USA
| | - Albert J. Sinusas
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, USA
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
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Bisgaard M, Houlind KC, Blankholm AD, Ringgaard S, Christensen J, Precht H. Validation of MRI assessment of foot perfusion for improving treatment of patients with peripheral artery disease. Radiography (Lond) 2024; 30:1116-1124. [PMID: 38797044 DOI: 10.1016/j.radi.2024.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/10/2024] [Accepted: 05/14/2024] [Indexed: 05/29/2024]
Abstract
INTRODUCTION Information on tissue perfusion in the foot is important when treating patients with chronic limb-threatening ischemia. This study aims to test the reliability of different magnetic resonance sequences when measuring perfusion in the foot. METHODS Sixteen healthy volunteers had their right foot scanned in a test/retest study with six different magnetic resonance sequences (BOLD, multi-echo gradient echo (mGRE), 2D and 3D pCASL, PASL FAIR, and DWI with intravoxel incoherent motion (IVIM) with quantitative measurements of perfusion. For five sequences, cuff-induced ischemia followed by a hyperactive response was measured. Images of the feet were segmented into angiosomes and perfusion data were extracted from the five angiosomes. RESULTS BOLD, PASL FAIR, mGRE, and DWI with IVIM had low mean differences between the first and second scans, while the results of 2D and 3D pCASL had the highest differences. Based on a paired t-test, BOLD, and FAIR were able to distinguish between perfusion and no perfusion in all angiosomes with p-values below 0.01. This was not the case with 2D and 3D pCASL with p-values above 0.05 in all angiosomes. The mGRE could not distinguish between perfusion and no perfusion in the lateral side of the foot. CONCLUSION BOLD, mGRE, pASL FAIR, and DWI with IVIM seem to give more robust results compared to 2D and 3D pCASL. Further studies on patients with peripheral artery disease should explore if the sequences can have clinical relevance when assessing tissue ischemia and results of revascularization. IMPLICATIONS FOR PRACTICE This study provides knowledge that could be used to improve the diagnosis of patient with chronic limb-threatening ischemia to explore tissue perfusion.
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Affiliation(s)
- M Bisgaard
- Department of Radiology, Kolding Hospital, Kolding, Denmark; Department of Regional Health Research, University of Southern Denmark, Odense, Denmark; Health Sciences Research Centre, UCL University College, Odense M, Denmark.
| | - K C Houlind
- Department of Regional Health Research, University of Southern Denmark, Odense, Denmark; Department of Vascular Surgery, Kolding Hospital, Kolding, Denmark.
| | - A D Blankholm
- Department of Radiology, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.
| | - S Ringgaard
- MR Research Center, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
| | - J Christensen
- Department of Radiology, Kolding Hospital, Kolding, Denmark.
| | - H Precht
- Department of Radiology, Kolding Hospital, Kolding, Denmark; Department of Regional Health Research, University of Southern Denmark, Odense, Denmark; Health Sciences Research Centre, UCL University College, Odense M, Denmark.
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Bäuchle TA, Stuprich CM, Loh M, Nagel AM, Uder M, Laun FB. Influence of Magnetic Field Strength on Intravoxel Incoherent Motion Parameters in Diffusion MRI of the Calf. Tomography 2024; 10:773-788. [PMID: 38787019 PMCID: PMC11126135 DOI: 10.3390/tomography10050059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/26/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024] Open
Abstract
Background: The purpose of this study was to investigate the dependence of Intravoxel Incoherent Motion (IVIM) parameters measured in the human calf on B0. Methods: Diffusion-weighted image data of eight healthy volunteers were acquired using five b-values (0-600 s/mm2) at rest and after muscle activation at 0.55 and 7 T. The musculus gastrocnemius mediale (GM, activated) was assessed. The perfusion fraction f and diffusion coefficient D were determined using segmented fits. The dependence on field strength was assessed using Student's t-test for paired samples and the Wilcoxon signed-rank test. A biophysical model built on the three non-exchanging compartments of muscle, venous blood, and arterial blood was used to interpret the data using literature relaxation times. Results: The measured perfusion fraction of the GM was significantly lower at 7 T, both for the baseline measurement and after muscle activation. For 0.55 and 7 T, the mean f values were 7.59% and 3.63% at rest, and 14.03% and 6.92% after activation, respectively. The biophysical model estimations for the mean proton-density-weighted perfusion fraction were 3.37% and 6.50% for the non-activated and activated states, respectively. Conclusions: B0 may have a significant effect on the measured IVIM parameters. The blood relaxation times suggest that 7 T IVIM may be arterial-weighted whereas 0.55 T IVIM may exhibit an approximately equal weighting of arterial and venous blood.
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Affiliation(s)
- Tamara Alice Bäuchle
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Christoph Martin Stuprich
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Martin Loh
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Armin Michael Nagel
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Michael Uder
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Frederik Bernd Laun
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
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Elsaid NMH, Peters DC, Galiana G, Sinusas AJ. Clinical physiology: the crucial role of MRI in evaluation of peripheral artery disease. Am J Physiol Heart Circ Physiol 2024; 326:H1304-H1323. [PMID: 38517227 DOI: 10.1152/ajpheart.00533.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 03/19/2024] [Accepted: 03/19/2024] [Indexed: 03/23/2024]
Abstract
Peripheral artery disease (PAD) is a common vascular disease that primarily affects the lower limbs and is defined by the constriction or blockage of peripheral arteries and may involve microvascular dysfunction and tissue injury. Patients with diabetes have more prominent disease of microcirculation and develop peripheral neuropathy, autonomic dysfunction, and medial vascular calcification. Early and accurate diagnosis of PAD and disease characterization are essential for personalized management and therapy planning. Magnetic resonance imaging (MRI) provides excellent soft tissue contrast and multiplanar imaging capabilities and is useful as a noninvasive imaging tool in the comprehensive physiological assessment of PAD. This review provides an overview of the current state of the art of MRI in the evaluation and characterization of PAD, including an analysis of the many applicable MR imaging techniques, describing the advantages and disadvantages of each approach. We also present recent developments, future clinical applications, and future MRI directions in assessing PAD. The development of new MR imaging technologies and applications in preclinical models with translation to clinical research holds considerable potential for improving the understanding of the pathophysiology of PAD and clinical applications for improving diagnostic precision, risk stratification, and treatment outcomes in patients with PAD.
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Affiliation(s)
- Nahla M H Elsaid
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, United States
| | - Dana C Peters
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, United States
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States
| | - Gigi Galiana
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, United States
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States
| | - Albert J Sinusas
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, United States
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States
- Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, United States
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Christensen NL, Sørensen J, Bouchelouche K, Madsen MA, Buhl CS, Tolbod LP. Repeatability of [ 15O]H 2O PET imaging for lower extremity skeletal muscle perfusion: a test-retest study. EJNMMI Res 2024; 14:11. [PMID: 38294730 PMCID: PMC10830956 DOI: 10.1186/s13550-024-01073-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 01/24/2024] [Indexed: 02/01/2024] Open
Abstract
BACKGROUND [15O]H2O PET/CT allows noninvasive quantification of tissue perfusion and can potentially play a future role in the diagnosis and treatment of peripheral artery disease. We aimed to evaluate the reliability of dynamic [15O]H2O PET imaging for measuring lower extremity skeletal muscle perfusion. Ten healthy participants underwent same-day test-retest study with six dynamic [15O]H2O PET scans of lower legs and feet. Manual volume-of-interests were drawn in skeletal muscles, and PET time activity curves were extracted. K1 values (mL/min/100 mL) were estimated using a single-tissue compartment model (1TCM), autoradiography (ARG), and parametric imaging with blood input functions obtained from separate heart scans. RESULTS Resting perfusion values in the muscle groups of the lower legs ranged from 1.18 to 5.38 mL/min/100 mL (ARG method). In the muscle groups of the feet, perfusion values ranged from 0.41 to 3.41 mL/min/100 mL (ARG method). Test-retest scans demonstrated a strong correlation and good repeatability for skeletal muscle perfusion with an intraclass correlation coefficient (ICC) of 0.88 and 0.87 and a repeatability coefficient of 34% and 53% for lower legs and feet, respectively. An excellent correlation was demonstrated when comparing volume-of-interest-based methods (1TCM and ARG) (lower legs: ICC = 0.96, feet: ICC = 0.99). Parametric images were in excellent agreement with the volume-of-interest-based ARG method (lower legs: ICC = 0.97, feet: ICC = 0.98). CONCLUSION Parametric images and volume-of-interest-based methods demonstrated comparable resting perfusion values in the lower legs and feet of healthy individuals. The largest variation was seen between individuals, whereas a smaller variation was seen between muscle groups. Repeated measurements of resting blood flow yielded a strong overall correlation for all methods.
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Affiliation(s)
- Nana Louise Christensen
- Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, 8200, Aarhus N, Denmark
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Department of Nuclear Medicine & PET, Aarhus University Hospital, Aarhus, Denmark
| | - Jens Sørensen
- Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, 8200, Aarhus N, Denmark
| | - Kirsten Bouchelouche
- Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, 8200, Aarhus N, Denmark
- Department of Nuclear Medicine & PET, Aarhus University Hospital, Aarhus, Denmark
| | - Michael Alle Madsen
- Department of Nuclear Medicine & PET, Aarhus University Hospital, Aarhus, Denmark
| | | | - Lars Poulsen Tolbod
- Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, 8200, Aarhus N, Denmark.
- Department of Nuclear Medicine & PET, Aarhus University Hospital, Aarhus, Denmark.
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Huang XC, Huang YL, Guo YT, Li SY, Gao C, Chen JX, Ma JY, He B. An experimental study for quantitative assessment of fatty infiltration and blood flow perfusion in quadriceps muscle of rats using IDEAL-IQ and BOLD-MRI for early diagnosis of sarcopenia. Exp Gerontol 2023; 183:112322. [PMID: 37929293 DOI: 10.1016/j.exger.2023.112322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 10/15/2023] [Accepted: 10/26/2023] [Indexed: 11/07/2023]
Abstract
BACKGROUND Severe sarcopenia may result in severe disability. Early diagnosis is currently the key to enhancing the treatment of sarcopenia, and there is an urgent need for a highly sensitive and dependable tool to evaluate the course of early sarcopenia in clinical practice. This study aims to investigate longitudinally the early diagnosability of magnetic resonance imaging (MRI)-based fat infiltration and blood flow perfusion technology in sarcopenia progression. METHODS 48 Sprague-Dawley rats were randomly assigned into six groups that were based on different periods of dexamethasone (DEX) injection (0, 2, 4, 6, 8, 10 days). Multimodal MRI was scanned to assess muscle mass. Grip strength and swimming exhaustion time of rats were measured to assess muscle strength and function. Immunofluorescence staining for CD31 was employed to assess skeletal muscle capillary formation, and western blot was used to detect vascular endothelial growth factor-A (VEGF-A) and muscle ring finger-1 (MuRF-1) protein expression. Subsequently, we analyzed the correlation between imaging and histopathologic parameters. A receiver operating characteristic (ROC) analysis was conducted to assess the effectiveness of quantitative MRI parameters for discriminating diagnosis in both pre- and post-modeling of DEX-induced sarcopenic rats. RESULTS Significant differences were found in PDFF, R2* and T2 values on day 2 of DEX-induction compared to the control group, occurring prior to the MRI-CSA values and limb grip strength on day 6 of induction and swimming exhaustion time on day 8 of induction. There is a strong correlation between MRI-CSA with HE-CSA values (r = 0.67; p < 0.001), oil red O (ORO) area with PDFF (r = 0.67; p < 0.001), microvascular density (MVD) (r = -0.79; p < 0.001) and VEGF-A (r = -0.73; p < 0.001) with R2*, MuRF-1 with MRI-CSA (r = -0.82; p < 0.001). The AUC of PDFF, R2*, and T2 values used for modeling evaluation are 0.81, 0.93, and 0.98, respectively. CONCLUSION Imaging parameters PDFF, R2*, and T2 can be used to sensitively evaluate early pathological changes in sarcopenia. The successful construction of a sarcopenia rat model can be assessed when PDFF exceeds 1.25, R2* exceeds 53.85, and T2 exceeds 33.88.
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Affiliation(s)
- Xin-Chen Huang
- Department of Radiology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Yi-Long Huang
- Department of Radiology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Yi-Tong Guo
- Department of Radiology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Si-Yu Li
- Department of Physiology, Faculty of Basic Medical Science, Kunming Medical University, Kunming, Yunnan, China
| | - Chao Gao
- Department of Radiology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Jia-Xin Chen
- Department of Radiology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Ji-Yao Ma
- Department of Radiology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Bo He
- Department of Radiology, The First Affiliated Hospital of Kunming Medical University, Kunming, China.
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Hosadurg N, Kramer CM. Magnetic Resonance Imaging Techniques in Peripheral Arterial Disease. Adv Wound Care (New Rochelle) 2023; 12:611-625. [PMID: 37058352 PMCID: PMC10468560 DOI: 10.1089/wound.2022.0161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/12/2023] [Indexed: 04/15/2023] Open
Abstract
Significance: Peripheral arterial disease (PAD) leads to a significant burden of morbidity and impaired quality of life globally. Diabetes is a significant risk factor accelerating the development of PAD with an associated increase in the risk of chronic wounds, tissue, and limb loss. Various magnetic resonance imaging (MRI) techniques are being increasingly acknowledged as useful methods of accurately assessing PAD. Recent Advances: Conventionally utilized MRI techniques for assessing macrovascular disease have included contrast enhanced magnetic resonance angiography (MRA), noncontrast time of flight MRA, and phase contrast MRI, but have significant limitations. In recent years, novel noncontrast MRI methods assessing skeletal muscle perfusion and metabolism such as arterial spin labeling (ASL), blood-oxygen-level dependent (BOLD) imaging, and chemical exchange saturation transfer (CEST) have emerged. Critical Issues: Conventional non-MRI (such as ankle-brachial index, arterial duplex ultrasonography, and computed tomographic angiography) and MRI based modalities image the macrovasculature. The underlying mechanisms of PAD that result in clinical manifestations are, however, complex, and imaging modalities that can assess the interaction between impaired blood flow, microvascular tissue perfusion, and muscular metabolism are necessary. Future Directions: Further development and clinical validation of noncontrast MRI methods assessing skeletal muscle perfusion and metabolism, such as ASL, BOLD, CEST, intravoxel incoherent motion microperfusion, and techniques that assess plaque composition, are advancing this field. These modalities can provide useful prognostic data and help in reliable surveillance of outcomes after interventions.
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Affiliation(s)
- Nisha Hosadurg
- Department of Cardiovascular Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Christopher M. Kramer
- Department of Cardiovascular Medicine, University of Virginia, Charlottesville, Virginia, USA
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Leiva K, Leizaola D, Gonzalez I, Dargam V, Alirezaei H, Kaile K, Robledo E, Hutcheson J, Godavarty A. Spatial-Temporal Oxygenation Mapping Using a Near-Infrared Optical Scanner: Towards Peripheral Vascular Imaging. Ann Biomed Eng 2023; 51:2035-2047. [PMID: 37204547 DOI: 10.1007/s10439-023-03229-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 05/02/2023] [Indexed: 05/20/2023]
Abstract
Near-infrared spectroscopy (NIRS)-based peripheral perfusion, or microcirculation, can be used to assess the severity of peripheral vascular dysfunction. A low-cost, portable non-contact near-infrared optical scanner (NIROS) was developed for spatio-temporal mapping of tissue oxygenation and perfusion in tissues. In vivo validation studies were carried out on control subjects (n = 3) to assess the ability of NIROS to measure real-time oxygenation changes in response to an occlusion paradigm on the dorsum of the hand. NIROS captured real-time tissue oxygenation changes with 95% correlation when compared to a commercial device. A feasibility peripheral imaging study was performed in a mouse model (n = 5) of chronic kidney disease (CKD) induced vascular calcification to assess differences in microcirculatory peripheral tissue oxygenation. The tissue oxygenation (in terms of oxy-, deoxy-, and total hemoglobin changes) due to the occlusion paradigm was distinctly different prior to (week-6) and after the onset of vascular calcification (week-12) in the murine tails. Future work will involve extensive studies to correlate these microcirculatory tissue oxygenation changes in the peripheral tail to the vascular calcification in the heart.
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Affiliation(s)
- Kevin Leiva
- Optical Imaging Laboratory, Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EC 2675, Miami, FL, 33174, USA
| | - Daniela Leizaola
- Optical Imaging Laboratory, Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EC 2675, Miami, FL, 33174, USA
| | - Isabella Gonzalez
- Optical Imaging Laboratory, Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EC 2675, Miami, FL, 33174, USA
| | - Valentina Dargam
- Cardiovascular Matrix Remodeling Laboratory, Department of Biomedical Engineering, Florida International University, Miami, FL, USA
| | - Haniyeh Alirezaei
- Optical Imaging Laboratory, Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EC 2675, Miami, FL, 33174, USA
| | - Kacie Kaile
- Optical Imaging Laboratory, Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EC 2675, Miami, FL, 33174, USA
| | - Edwin Robledo
- Optical Imaging Laboratory, Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EC 2675, Miami, FL, 33174, USA
| | - Joshua Hutcheson
- Cardiovascular Matrix Remodeling Laboratory, Department of Biomedical Engineering, Florida International University, Miami, FL, USA
| | - Anuradha Godavarty
- Optical Imaging Laboratory, Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EC 2675, Miami, FL, 33174, USA.
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Nai YH, Wang X, Gan J, Lian CPL, Kirwan RF, Tan FSL, Hausenloy DJ. Effects of fitting methods, high b-values and image quality on diffusion and perfusion quantification and reproducibility in the calf. Comput Biol Med 2023; 157:106746. [PMID: 36924736 DOI: 10.1016/j.compbiomed.2023.106746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/17/2023] [Accepted: 03/04/2023] [Indexed: 03/08/2023]
Abstract
PURPOSES The study aimed to optimize diffusion-weighted imaging (DWI) image acquisition and analysis protocols in calf muscles by investigating the effects of different model-fitting methods, image quality, and use of high b-value and constraints on parameters of interest (POIs). The optimized modeling methods were used to select the optimal combinations of b-values, which will allow shorter acquisition time while achieving the same reliability as that obtained using 16 b-values. METHODS Test-retest baseline and high-quality DWI images of ten healthy volunteers were acquired on a 3T MR scanner, using 16 b-values, including a high b-value of 1200 s/mm2, and structural T1-weighted images for calf muscle delineation. Three and six different fitting methods were used to derive ADC from monoexponential (ME) model and Dd, fp, and Dp from intravoxel incoherent motion (IVIM) model, with or without the high b-value. The optimized ME and IVIM models were then used to determine the optimal combinations of b-values, obtainable with the least number of b-values, using the selection criteria of coefficient of variance (CV) ≤10% for all POIs. RESULTS The find minimum multivariate algorithm was more flexible and yielded smaller fitting errors. The 2-steps fitting method, with fixed Dd, performed the best for IVIM model. The inclusion of high b-value reduced outliers, while constraints improved 2-steps fitting only. CONCLUSIONS The optimal numbers of b-values for ME and IVIM models were nine and six b-values respectively. Test-retest reliability analyses showed that only ADC and Dd were reliable for calf diffusion evaluation, with CVs of 7.22% and 4.09%.
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Affiliation(s)
- Ying-Hwey Nai
- Clinical Imaging Research Centre, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
| | - Xiaomeng Wang
- Cardiovascular & Metabolic Disorders Program, Duke-National University of Singapore Medical School, Singapore
| | | | - Cheryl Pei Ling Lian
- Health and Social Sciences Cluster, Singapore Institute of Technology, Singapore
| | - Ryan Fraser Kirwan
- Infocomm Technology Cluster, Singapore Institute of Technology, Singapore
| | - Forest Su Lim Tan
- Infocomm Technology Cluster, Singapore Institute of Technology, Singapore
| | - Derek J Hausenloy
- Cardiovascular & Metabolic Disorders Program, Duke-National University of Singapore Medical School, Singapore; National Heart Research Institute Singapore, National Heart Centre, Singapore; Yong Loo Lin School of Medicine, National University Singapore, Singapore; The Hatter Cardiovascular Institute, University College London, London, UK
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Eck BL, Yang M, Elias JJ, Winalski CS, Altahawi F, Subhas N, Li X. Quantitative MRI for Evaluation of Musculoskeletal Disease: Cartilage and Muscle Composition, Joint Inflammation, and Biomechanics in Osteoarthritis. Invest Radiol 2023; 58:60-75. [PMID: 36165880 PMCID: PMC10198374 DOI: 10.1097/rli.0000000000000909] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
ABSTRACT Magnetic resonance imaging (MRI) is a valuable tool for evaluating musculoskeletal disease as it offers a range of image contrasts that are sensitive to underlying tissue biochemical composition and microstructure. Although MRI has the ability to provide high-resolution, information-rich images suitable for musculoskeletal applications, most MRI utilization remains in qualitative evaluation. Quantitative MRI (qMRI) provides additional value beyond qualitative assessment via objective metrics that can support disease characterization, disease progression monitoring, or therapy response. In this review, musculoskeletal qMRI techniques are summarized with a focus on techniques developed for osteoarthritis evaluation. Cartilage compositional MRI methods are described with a detailed discussion on relaxometric mapping (T 2 , T 2 *, T 1ρ ) without contrast agents. Methods to assess inflammation are described, including perfusion imaging, volume and signal changes, contrast-enhanced T 1 mapping, and semiquantitative scoring systems. Quantitative characterization of structure and function by bone shape modeling and joint kinematics are described. Muscle evaluation by qMRI is discussed, including size (area, volume), relaxometric mapping (T 1 , T 2 , T 1ρ ), fat fraction quantification, diffusion imaging, and metabolic assessment by 31 P-MR and creatine chemical exchange saturation transfer. Other notable technologies to support qMRI in musculoskeletal evaluation are described, including magnetic resonance fingerprinting, ultrashort echo time imaging, ultrahigh-field MRI, and hybrid MRI-positron emission tomography. Challenges for adopting and using qMRI in musculoskeletal evaluation are discussed, including the need for metal artifact suppression and qMRI standardization.
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Affiliation(s)
- Brendan L. Eck
- Program of Advanced Musculoskeletal Imaging, Cleveland Clinic, Cleveland, OH, USA
- Imaging Instute, Cleveland Clinic, Cleveland, OH, USA
| | - Mingrui Yang
- Program of Advanced Musculoskeletal Imaging, Cleveland Clinic, Cleveland, OH, USA
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - John J. Elias
- Program of Advanced Musculoskeletal Imaging, Cleveland Clinic, Cleveland, OH, USA
- Department of Research, Cleveland Clinic Akron General, Akron, OH, USA
| | - Carl S. Winalski
- Program of Advanced Musculoskeletal Imaging, Cleveland Clinic, Cleveland, OH, USA
- Imaging Instute, Cleveland Clinic, Cleveland, OH, USA
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Faysal Altahawi
- Program of Advanced Musculoskeletal Imaging, Cleveland Clinic, Cleveland, OH, USA
- Imaging Instute, Cleveland Clinic, Cleveland, OH, USA
| | - Naveen Subhas
- Program of Advanced Musculoskeletal Imaging, Cleveland Clinic, Cleveland, OH, USA
- Imaging Instute, Cleveland Clinic, Cleveland, OH, USA
| | - Xiaojuan Li
- Program of Advanced Musculoskeletal Imaging, Cleveland Clinic, Cleveland, OH, USA
- Imaging Instute, Cleveland Clinic, Cleveland, OH, USA
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
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11
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Pantoja JL, Ali F, Baril DT, Farley SM, Boynton S, Finn JP, Hu P, Lawrence PF. Arterial spin labeling magnetic resonance imaging quantifies tissue perfusion around foot ulcers. J Vasc Surg Cases Innov Tech 2022; 8:817-824. [PMID: 36510629 PMCID: PMC9735268 DOI: 10.1016/j.jvscit.2022.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/28/2022] [Indexed: 11/05/2022] Open
Abstract
Objective Tools that quantify tissue perfusion of the foot are deficient, contributing to the uncertainty in predicting ulcer healing potential. This pilot study aims to quantify peri-wound foot perfusion at various tissue depths using a novel application of pseudo-continuous arterial spin labeling magnetic resonance imaging. Methods Ten diabetic patients with neuropathic wounds and 20 healthy volunteers without wounds were recruited. Wounds were graded according to the Wound, Ischemia, Foot Infection (WIfI) system. All subjects underwent a noncontrasted ASL MRI of the foot for perfusion measurements. For healthy volunteers, perfusion was compared at rest and during sustained toe flexion between four regions: lateral plantar, medial plantar, lateral calcaneal, and medial calcaneal. Evaluations of diabetic volunteers compared perfusion between four zones: wound, near border, far border, and remote. Remote zone perfusion in diabetics was compared with perfusion in the plantar foot of healthy volunteers. Results There were 11 wounds, which were located over the metatarsal heads in five, the stump of a transmetatarsal amputation in three, the heel in two, and the mid foot in one. The median WIfI stage was 2. One patient had a WIfI ischemia grade of 1; the remaining patients' grades were 0. The mean ankle-brachial index was 1.0 ± 0.3. There were two patients with a WIfI foot infection grade of 1; the remaining patients' grades were 0. In healthy volunteers, plantar foot perfusion with sustained toe flexion was 43.9 ± 1.7 mL/100g/min and significantly higher than perfusion at rest (27.3 ± 2.7 mL/100g/min; P < .001). In diabetic patients, perfusion at the wound, near border, far border, and remote regions was 96.1 ± 10.7, 92.7 ± 9.4, 73.4 ± 8.2, and 62.8 ± 2.7 mL/100g/min. Although this perfusion pattern persisted throughout the depth of the wound, perfusion decreased with tissue depth. In the near border, perfusion at 20% of the wound depth was 124.0 ± 35.6 mL/100g/min and 69.9 ± 10.1 mL/100g/min at 100% (P = .006). Lastly, remote perfusion in diabetics was 2.3 times the plantar perfusion in healthy volunteers (27.3 ± 2.7 mL/100g/min; P < .001). Conclusions The pattern of resting tissue perfusion around nonischemic diabetic foot ulcers was successfully quantified with arterial spin labeling magnetic resonance imaging. Diabetic patients with wounds were hyperemic compared with healthy volunteers. There was a 1.5-fold increase in peri-wound tissue perfusion relative to the rest of the foot. This study is the first step in developing a tool to assess the perfusion deficit in ischemic wounds.
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Affiliation(s)
- Joe Luis Pantoja
- Division of Vascular and Endovascular Surgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA,Correspondence: Dr Joe Luis Pantoja, MD, Division of Vascular and Endovascular Surgery, David Geffen School of Medicine, University of California Los Angeles, Medical Plaza Driveway, Ste 530, Los Angeles, CA 90095
| | - Fadil Ali
- Department of Radiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Donald T. Baril
- Division of Vascular Surgery, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Steven M. Farley
- Division of Vascular and Endovascular Surgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Scott Boynton
- Division of Vascular and Endovascular Surgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - J. Paul Finn
- Department of Radiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Peng Hu
- Department of Radiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Peter F. Lawrence
- Division of Vascular and Endovascular Surgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
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12
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Tang H, Yu L, Suo S, Hu Y, Wang J, Xu J, Lu Q, Zhou Y. Evaluation of skeletal muscle perfusion changes in patients with peripheral artery disease before and after percutaneous transluminal angioplasty using multiparametric MR imaging. Magn Reson Imaging 2022; 93:157-162. [DOI: 10.1016/j.mri.2022.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 06/10/2022] [Accepted: 08/02/2022] [Indexed: 11/30/2022]
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13
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Galanakis N, Maris TG, Kontopodis N, Tsetis K, Kehagias E, Tsetis D. Perfusion imaging techniques in lower extremity peripheral arterial disease. Br J Radiol 2022; 95:20211203. [PMID: 35522774 PMCID: PMC10996332 DOI: 10.1259/bjr.20211203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 04/17/2022] [Accepted: 04/21/2022] [Indexed: 11/05/2022] Open
Abstract
Lower limb peripheral arterial disease (PAD) characterizes the impairment of blood flow to extremities caused by arterial stenoses or occlusions. Evaluation of PAD is based on clinical examination, calculation of ankle-brachial index and imaging studies such as ultrasound, CT, MRI and digital subtraction angiography. These modalities provide significant information about location, extension and severity of macrovasular lesions in lower extremity arterial system. However, they can be also used to evaluate limb perfusion, using appropriate techniques and protocols. This information may be valuable for assessment of the severity of ischemia and detection of hypoperfused areas. Moreover, they can be used for planning of revascularization strategy in patients with severe PAD and evaluation of therapeutic outcome. These techniques may also determine prognosis and amputation risk in patients with PAD. This review gives a basic overview of the perfusion techniques for lower limbs provided by imaging modalities such as ultrasound, CT, MRI, digital subtraction angiography and scintigraphy and their clinical applications for evaluation of PAD and revascularization outcome.
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Affiliation(s)
- Nikolaos Galanakis
- Department of Medical Imaging, University Hospital Heraklion,
University of Crete Medical School,
Heraklion, Greece
| | - Thomas G Maris
- Department of Medical Physics, University Hospital Heraklion,
University of Crete Medical School,
Heraklion, Greece
| | - Nikolaos Kontopodis
- Vascular Surgery Unit, Department of Cardiothoracic and
Vascular Surgery, University Hospital Heraklion, University of Crete
Medical School, Heraklion,
Greece
| | - Konstantinos Tsetis
- Department of Medical Imaging, University Hospital Heraklion,
University of Crete Medical School,
Heraklion, Greece
| | - Elias Kehagias
- Department of Medical Imaging, University Hospital Heraklion,
University of Crete Medical School,
Heraklion, Greece
| | - Dimitrios Tsetis
- Department of Medical Imaging, University Hospital Heraklion,
University of Crete Medical School,
Heraklion, Greece
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14
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Stacy MR. Molecular Imaging of Lower Extremity Peripheral Arterial Disease: An Emerging Field in Nuclear Medicine. Front Med (Lausanne) 2022; 8:793975. [PMID: 35096884 PMCID: PMC8789656 DOI: 10.3389/fmed.2021.793975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 12/14/2021] [Indexed: 11/13/2022] Open
Abstract
Peripheral arterial disease (PAD) is an atherosclerotic disorder of non-coronary arteries that is associated with vascular stenosis and/or occlusion. PAD affecting the lower extremities is characterized by a variety of health-related consequences, including lifestyle-limiting intermittent claudication, ulceration of the limbs and/or feet, increased risk for lower extremity amputation, and increased mortality. The diagnosis of lower extremity PAD is typically established by using non-invasive tests such as the ankle-brachial index, toe-brachial index, duplex ultrasound, and/or angiography imaging studies. While these common diagnostic tools provide hemodynamic and anatomical vascular assessments, the potential for non-invasive physiological assessment of the lower extremities has more recently emerged through the use of magnetic resonance- and nuclear medicine-based approaches, which can provide insight into the functional consequences of PAD-related limb ischemia. This perspectives article specifically highlights and discusses the emerging applications of clinical nuclear medicine techniques for molecular imaging investigations in the setting of lower extremity PAD.
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Affiliation(s)
- Mitchel R Stacy
- Center for Regenerative Medicine, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Division of Vascular Diseases and Surgery, Department of Surgery, The Ohio State University College of Medicine, Columbus, OH, United States
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15
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Caroca S, Villagran D, Chabert S. Four functional magnetic resonance imaging techniques for skeletal muscle exploration, a systematic review. Eur J Radiol 2021; 144:109995. [PMID: 34628310 DOI: 10.1016/j.ejrad.2021.109995] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/27/2021] [Accepted: 09/29/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND The study of muscle health has become more relevant lately, due to global aging and a higher incidence of musculoskeletal pathologies. Current exploration techniques, such as electromyography, do not provide accurate spatial information. OBJECTIVE The objective of this work is to perform a systematic review of the literature to synthesize the contributions that can offer functional MRI techniques commonly used in neuroimaging, applied to skeletal muscle: Blood Oxygen Level Dependent (BOLD), IntraVoxel Incoherent Motion (IVIM), Arterial Spin Labeling (ASL) and Dynamic Contrast Enhanced (DCE). EVIDENCE ACQUISITION Web of Science and Medline databases were searched, over the last 10 years, focused on the use of BOLD, ASL, IVIM or DCE in skeletal muscle. EVIDENCE SYNTHESIS 59 articles were included after applying the selection criteria. 37 studies were performed in healthy subjects, and 22 in patients with different pathologies: in peripheral arterial disease, systemic sclerosis, diabetes, osteoporosis, adolescent idiopathic scoliosis, and dermatomyositis. Reference values in healthy subjects still vary in some cases. CONCLUSION The studies show the feasibility of implementing functional MRI through BOLD, ASL, IVIM or DCE imaging in several muscles and their possible utility in different pathologies. A synthesis of how to implement such exploration is given here. CLINICAL IMPACT These four techniques are based on sequences already present in clinical MRI scanners, therefore, their use for functional muscle exploration does not require additional investment. These techniques allow visualization and quantification of parameters associated with the vascular health of the muscles and represent interesting support for musculoskeletal exploration.
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Affiliation(s)
- Sergio Caroca
- Biomedical Engineering Department, Universidad de Valparaiso, Valparaíso, Chile
| | - Diego Villagran
- Servicio de Imagenología, Hospital Carlos van Buren, Valparaíso, Chile
| | - Steren Chabert
- Biomedical Engineering Department, Universidad de Valparaiso, Valparaíso, Chile; CINGS, Centro de Investigación y Desarrollo en INGeniería en Salud, Universidad de Valparaiso, Valparaíso, Chile; Millennium Nucleus for Cardiovascular Magnetic Resonance, Chile.
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16
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Englund EK, Reiter DA, Shahidi B, Sigmund EE. Intravoxel Incoherent Motion Magnetic Resonance Imaging in Skeletal Muscle: Review and Future Directions. J Magn Reson Imaging 2021; 55:988-1012. [PMID: 34390617 DOI: 10.1002/jmri.27875] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 12/29/2022] Open
Abstract
Throughout the body, muscle structure and function can be interrogated using a variety of noninvasive magnetic resonance imaging (MRI) methods. Recently, intravoxel incoherent motion (IVIM) MRI has gained momentum as a method to evaluate components of blood flow and tissue diffusion simultaneously. Much of the prior research has focused on highly vascularized organs, including the brain, kidney, and liver. Unique aspects of skeletal muscle, including the relatively low perfusion at rest and large dynamic range of perfusion between resting and maximal hyperemic states, may influence the acquisition, postprocessing, and interpretation of IVIM data. Here, we introduce several of those unique features of skeletal muscle; review existing studies of IVIM in skeletal muscle at rest, in response to exercise, and in disease states; and consider possible confounds that should be addressed for muscle-specific evaluations. Most studies used segmented nonlinear least squares fitting with a b-value threshold of 200 sec/mm2 to obtain IVIM parameters of perfusion fraction (f), pseudo-diffusion coefficient (D*), and diffusion coefficient (D). In healthy individuals, across all muscles, the average ± standard deviation of D was 1.46 ± 0.30 × 10-3 mm2 /sec, D* was 29.7 ± 38.1 × 10-3 mm2 /sec, and f was 11.1 ± 6.7%. Comparisons of reported IVIM parameters in muscles of the back, thigh, and leg of healthy individuals showed no significant difference between anatomic locations. Throughout the body, exercise elicited a positive change of all IVIM parameters. Future directions including advanced postprocessing models and potential sequence modifications are discussed. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Erin K Englund
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - David A Reiter
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, Georgia, USA.,Department of Orthopedics, Emory University, Atlanta, Georgia, USA
| | - Bahar Shahidi
- Department of Orthopaedic Surgery, UC San Diego, San Diego, California, USA
| | - Eric E Sigmund
- Department of Radiology, New York University Grossman School of Medicine, NYU Langone Health, New York, New York, USA.,Center for Advanced Imaging and Innovation (CAI2R), Bernard and Irene Schwarz Center for Biomedical Imaging (CBI), NYU Langone Health, New York, New York, USA
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17
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Galanakis N, Maris TG, Kalaitzakis G, Kontopodis N, Matthaiou N, Charalambous S, Tsetis K, Ioannou CV, Karantanas A, Tsetis D. Evaluation of foot hypoperfusion and estimation of percutaneous transluminal angioplasty outcome in patients with critical limb ischemia using intravoxel incoherent motion microperfusion MRI. Br J Radiol 2021; 94:20210215. [PMID: 34233490 DOI: 10.1259/bjr.20210215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVES To emerge hypoperfusion of lower limbs in patients with critical limb ischemia (CLI) using Intravoxel Incoherent Motion microperfusion magnetic resonance imaging (IVIM-MRI). Moreover to examine the ability of IVIM-MRI to differentiate patients with severe peripheral arterial disease (PAD) from normal subjects and evaluate the percutaneous transluminal angioplasty (PTA) results in patients with CLI. METHODS Eight patients who presented with CLI and six healthy volunteers were examined. The patients underwent IVIM-MRI of lower extremity before and following PTA. The imaging protocol included sagittal diffusion-weighted (DW) sequences. DW images were analyzed and color parametric maps of the micro-circulation of blood inside the capillary network (D*) were constructed. The studies were evaluated by two observers to define interobserver reproducibility. RESULTS Technical success was achieved in all patients (8/8). The mean ankle-brachial index increased from 0.35 ± 0.2 to 0.76 ± 0.25 (p < 0.05). Successful revascularization improved IVIM microperfusion. Mean D* increased from 279.88 ± 13.47 10-5 mm2/s to 331.51 ± 31 10-5 mm2/s, following PTA, p < 0.05. Moreover, PAD patients presented lower D* values as compared to healthy individuals (279.88 ± 13.47 10-5 mm2/s vs 332.47 ± 22.95 10-5 mm2/s, p < 0.05, respectively). Good interobserver agreement was obtained with an ICC = 0.84 (95% CI 0.64-0.93). CONCLUSIONS IVIM-MRI can detect differences in microperfusion between patients with PAD and healthy individuals. Moreover, significant restitution of IVIM microperfusion is found following successful PTA. ADVANCES IN KNOWLEDGE IVIM-MRI is a safe, reproducible and effective modality for evaluation of lower limb hypoperfusion in patients with PAD. It seems also to be a helpful tool to detect changes of tissue perfusion in patients with CLI following revascularization.
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Affiliation(s)
- Nikolaos Galanakis
- Department of Medical Imaging, University Hospital Heraklion, University of Crete Medical School, Voutes, Heraklion, Greece
| | - Thomas G Maris
- Department of Medical Physics, University Hospital Heraklion, University of Crete Medical School, Voutes, Heraklion, Greece
| | - Georgios Kalaitzakis
- Department of Medical Physics, University Hospital Heraklion, University of Crete Medical School, Voutes, Heraklion, Greece
| | - Nikolaos Kontopodis
- Vascular Surgery Unit, Department of Cardiothoracic and Vascular Surgery, University Hospital Heraklion, University of Crete Medical School, Voutes, Heraklion, Greece
| | - Nikolas Matthaiou
- Department of Medical Imaging, University Hospital Heraklion, University of Crete Medical School, Voutes, Heraklion, Greece
| | - Stavros Charalambous
- Department of Medical Imaging, University Hospital Heraklion, University of Crete Medical School, Voutes, Heraklion, Greece
| | - Konstantinos Tsetis
- Department of Medical Imaging, University Hospital Heraklion, University of Crete Medical School, Voutes, Heraklion, Greece
| | - Christos V Ioannou
- Vascular Surgery Unit, Department of Cardiothoracic and Vascular Surgery, University Hospital Heraklion, University of Crete Medical School, Voutes, Heraklion, Greece
| | - Apostolos Karantanas
- Department of Medical Imaging, University Hospital Heraklion, University of Crete Medical School, Voutes, Heraklion, Greece
| | - Dimitrios Tsetis
- Department of Medical Imaging, University Hospital Heraklion, University of Crete Medical School, Voutes, Heraklion, Greece
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18
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Atrial Fibrillation is Associated with Femoropopliteal Totally Occlusive In-Stent Restenosis: A Single-Center, Retrospective, Observational Study. J Interv Cardiol 2021; 2021:8852466. [PMID: 33623483 PMCID: PMC7875648 DOI: 10.1155/2021/8852466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 01/18/2021] [Accepted: 01/21/2021] [Indexed: 11/24/2022] Open
Abstract
Introduction The proportion of patients with comorbid atrial fibrillation (AF) and peripheral artery disease (PAD) has increased in this era. This study aimed to assess the relationship between AF and totally occlusive in-stent restenosis (ISR) in femoropopliteal (FP) lesions. Methods In this study, 363 patients (461 stents) who underwent endovascular therapy with de novo stent implantation in our hospital between April 2007 and December 2016 were retrospectively evaluated. The patients were divided into two groups according to the AF status (AF group, 61 patients; sinus group, 302 patients). The primary endpoint was the incidence of totally occlusive ISR within 3 years. The secondary endpoint was the incidence of acute limb ischemia (ALI) due to FP stent occlusion. Results Baseline characteristics were similar, except for higher age and a lower prevalence of dyslipidemia in the AF group. The incidence of a totally occlusive ISR was higher in the AF group than in the sinus group (29.5% vs. 14.6%, p=0.004). A multiple Cox regression model suggested that presence of AF (hazard ratio, 2.10) and CTO lesion (hazard ratio, 1.97) which were the independent predictors of a totally occlusive ISR within 3 years. The incidence of ALI was significantly higher in the AF group than in the sinus group (3.9% vs. 0%, p=0.0001). In the AF group, the introduction of an anticoagulant did not prevent the occurrence of totally occlusive ISR (p=0.71) for ALI (p=0.79). Conclusions AF is independently associated with totally occlusive ISR of FP stents; however, anticoagulant use does not prevent stent occlusion.
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19
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Karlas A, Masthoff M, Kallmayer M, Helfen A, Bariotakis M, Fasoula NA, Schäfers M, Seidensticker M, Eckstein HH, Ntziachristos V, Wildgruber M. Multispectral optoacoustic tomography of peripheral arterial disease based on muscle hemoglobin gradients-a pilot clinical study. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:36. [PMID: 33553329 PMCID: PMC7859778 DOI: 10.21037/atm-20-3321] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Background Current imaging assessment of peripheral artery disease (PAD) relies on anatomical cross-sectional visualizations of the affected arteries. Multispectral optoacoustic tomography (MSOT) is a novel molecular imaging technique that provides direct and label-free visualizations of soft tissue perfusion and oxygenation. Methods MSOT was prospectively assessed in a pilot trial in healthy volunteers (group n1=4, mean age 31, 50% male and group n3=4, mean age 37.3, 75% male) and patients with intermittent claudication (group n2=4, mean age 72, 75% male, PAD stage IIb). We conducted cuff-induced ischemia (group n1) and resting state measurements (groups n2 and n3) over the calf region. Spatially resolved mapping of oxygenated (HbO2), deoxygenated (Hb) and total (THb) hemoglobin, as well as oxygen saturation (SO2), were measured via hand-held hybrid MSOT-Ultrasound based purely on hemoglobin contrast. Results Calf measurements in healthy volunteers revealed distinct dynamics for HbO2, Hb, THb and SO2 under cuff-induced ischemia. HbO2, THb and SO2 levels were significantly impaired in PAD patients compared to healthy volunteers (P<0.05 for all parameters). Revascularization led to significant improvements in HbO2 of the affected limb. Conclusions Clinical MSOT allows for non-invasive, label-free and real-time imaging of muscle oxygenation in health and disease with implications for diagnostics and therapy assessment in PAD.
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Affiliation(s)
- Angelos Karlas
- Chair of Biological Imaging, School of Medicine, Technical University of Munich, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München (GmbH), Neuherberg, Germany.,Clinic of Vascular and Endovascular Surgery, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
| | - Max Masthoff
- Department for Clinical Radiology, University Hospital Münster, Münster, Germany
| | - Michael Kallmayer
- Clinic of Vascular and Endovascular Surgery, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
| | - Anne Helfen
- Department for Clinical Radiology, University Hospital Münster, Münster, Germany
| | - Michail Bariotakis
- Chair of Biological Imaging, School of Medicine, Technical University of Munich, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München (GmbH), Neuherberg, Germany
| | - Nikolina Alexia Fasoula
- Chair of Biological Imaging, School of Medicine, Technical University of Munich, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München (GmbH), Neuherberg, Germany
| | - Michael Schäfers
- Department for Nuclear Medicine and European Institute for Molecular Imaging, University Hospital Münster, Münster, Germany
| | - Max Seidensticker
- Department for Radiology, University Hospital, LMU Munich, München, Germany
| | - Hans-Henning Eckstein
- Clinic of Vascular and Endovascular Surgery, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
| | - Vasilis Ntziachristos
- Chair of Biological Imaging, School of Medicine, Technical University of Munich, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München (GmbH), Neuherberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
| | - Moritz Wildgruber
- Department for Clinical Radiology, University Hospital Münster, Münster, Germany.,Department for Radiology, University Hospital, LMU Munich, München, Germany
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20
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Evaluation of Skeletal Muscle Microcirculation and Reserve Function of the Type 2 Diabetes with Contrast-Enhanced Ultrasonography. Ultrasound Q 2020; 36:38-42. [PMID: 31264978 DOI: 10.1097/ruq.0000000000000459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE This study aimed to discuss clinical application value of contrast-enhanced ultrasonography on lesion skeletal muscle microcirculation and arterial perfusion reserve in type 2 diabetes mellitus and complicated microvessels. METHODS Patients in the control group, type 2 diabetes mellitus (DM) group, diabetic microangiopathy (DM + MC) group underwent contrast-enhanced ultrasonography before and after temporary arterial occlusion to observe blood perfusion of gastrocnemius muscle; draw the time-intensity curve of arteriole, muscular tissue, and venule, and obtain perfusion parameters such as contrast agent arrival time and contrast agent transit time. Blood glucose, insulin, insulin resistance index, and relevant blood rheology parameters were measured. RESULTS Contrast agent transit time of the DM + MC group before arterial occlusion was significantly longer than that of the DM group and control group (P < 0.05). Contrast agent transit time of the DM + MC group after temporary arterial occlusion was significantly longer than that of the DM group and control group (P < 0.05). Contrast agent transit time of △artery-muscle, △artery-vein, and △muscle-vein of the DM group and control group and △artery-muscle of the DM + MC group after arterial occlusion was significantly shortened, when compared with that before arterial occlusion (P < 0.05). For △muscle-vein and △artery-vein contrast agent transit time in the DM + MC group, the difference was not statistically significant. By comparing blood glucose, insulin, insulin resistance index, and relevant blood rheology parameters among the DM + MC group, DM group, and control group, the difference was statistically significant, and there was a good correlation. CONCLUSION Contrast-enhanced ultrasonography can be used to evaluate skeletal muscle microcirculation disturbance and arterial reserve function of patients who had type 2 diabetic microangiopathy.
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21
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Ohno N, Miyati T, Fujihara S, Gabata T, Kobayashi S. Biexponential analysis of intravoxel incoherent motion in calf muscle before and after exercise: Comparisons with arterial spin labeling perfusion and T2. Magn Reson Imaging 2020; 72:42-48. [DOI: 10.1016/j.mri.2020.06.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/18/2020] [Accepted: 06/09/2020] [Indexed: 12/26/2022]
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22
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Suo S, Tang H, Lu Q, Zhang L, Ni Q, Cao M, Chen Z, Zhao H, Sun B, Xu J. Blood oxygenation level-dependent cardiovascular magnetic resonance of the skeletal muscle in healthy adults: Different paradigms for provoking signal alterations. Magn Reson Med 2020; 85:1590-1601. [PMID: 32936484 DOI: 10.1002/mrm.28495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 07/07/2020] [Accepted: 08/03/2020] [Indexed: 12/18/2022]
Abstract
PURPOSE Stress blood oxygenation level-dependent (BOLD) cardiovascular magnetic resonance allows for quantitative evaluation of blood flow reserve in skeletal muscles. This study aimed to prospectively compare three commonly used skeletal BOLD cardiovascular magnetic resonance paradigms in healthy adults: gas inhalation, cuff compression-induced ischemia and postocclusive reactive hyperemia, and exercise. METHODS Twelve young (22 ± 0.9 years) and 10 elderly (58 ± 5.0 years) healthy subjects underwent BOLD cardiovascular magnetic resonance under the three paradigms. T 2 ∗ signal intensity time curves were generated and quantitative parameters were calculated. Meanwhile, stress transcutaneous oxygen pressure measurements were obtained as comparison. Measurement reproducibility was assessed with intraclass correlation coefficients. Differences in the T 2 ∗ BOLD variation, the correlation with transcutaneous oxygen pressure, and the age-related change between paradigms were statistically analyzed. RESULTS Minimum ischemic value and maximum hyperemic peak value showed the highest interobserver and interscan reproducibilities (intraclass correlation coefficient >0.90). The plantar dorsiflexion exercise paradigm elicited the largest T 2 ∗ BOLD variation (15.48% ± 10.56%), followed by ischemia (8.30% ± 6.33%). Negligible to weak changes were observed during gas inhalation. Correlations with transcutaneous oxygen pressure measurements were found in the ischemic phase (r = 0.966; P < .001) and in the postexercise phase (r = -0.936; P < .001). Minimum ischemic value, maximum hyperemic peak value, maximum postexercise value, and slope of postexercise signal decay showed significant differences between young and elderly subjects (P < .01). CONCLUSION Ischemia and reactive hyperemia have superior reproducibility, and exercise could induce the largest T 2 ∗ variation. Key parameters from the two paradigms show age-related differences.
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Affiliation(s)
- Shiteng Suo
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Biomedical Instrument Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Hui Tang
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Qing Lu
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Lan Zhang
- Department of Vascular Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Qihong Ni
- Department of Vascular Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Mengqiu Cao
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Zengai Chen
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Huilin Zhao
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Beibei Sun
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jianrong Xu
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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23
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Manning WJ. Journal of Cardiovascular Magnetic Resonance: 2017/2018 in review. J Cardiovasc Magn Reson 2019; 21:79. [PMID: 31884956 PMCID: PMC6936125 DOI: 10.1186/s12968-019-0594-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 12/14/2022] Open
Abstract
There were 89 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2017, including 76 original research papers, 4 reviews, 5 technical notes, 1 guideline, and 3 corrections. The volume was down slightly from 2017 with a corresponding 15% decrease in manuscript submissions from 405 to 346 and thus reflects a slight increase in the acceptance rate from 25 to 26%. The decrease in submissions for the year followed the initiation of the increased author processing charge (APC) for Society for Cardiovascular Magnetic Resonance (SCMR) members for manuscripts submitted after June 30, 2018. The quality of the submissions continues to be high. The 2018 JCMR Impact Factor (which is published in June 2019) was slightly lower at 5.1 (vs. 5.46 for 2017; as published in June 2018. The 2018 impact factor means that on average, each JCMR published in 2016 and 2017 was cited 5.1 times in 2018. Our 5 year impact factor was 5.82.In accordance with Open-Access publishing guidelines of BMC, the JCMR articles are published on-line in a continuus fashion in the chronologic order of acceptance, with no collating of the articles into sections or special thematic issues. For this reason, over the years, the Editors have felt that it is useful for the JCMR audience to annually summarize the publications into broad areas of interest or themes, so that readers can view areas of interest in a single article in relation to each other and contemporaneous JCMR publications. In this publication, the manuscripts are presented in broad themes and set in context with related literature and previously published JCMR papers to guide continuity of thought within the journal. In addition, as in the past two years, I have used this publication to also convey information regarding the editorial process and as a "State of our JCMR."This is the 12th year of JCMR as an open-access publication with BMC (formerly known as Biomed Central). The timing of the JCMR transition to the open access platform was "ahead of the curve" and a tribute to the vision of Dr. Matthias Friedrich, the SCMR Publications Committee Chair and Dr. Dudley Pennell, the JCMR editor-in-chief at the time. The open-access system has dramatically increased the reading and citation of JCMR publications and I hope that you, our authors, will continue to send your very best, high quality manuscripts to JCMR for consideration. It takes a village to run a journal and I thank our very dedicated Associate Editors, Guest Editors, Reviewers for their efforts to ensure that the review process occurs in a timely and responsible manner. These efforts have allowed the JCMR to continue as the premier journal of our field. This entire process would also not be possible without the dedication and efforts of our managing editor, Diana Gethers. Finally, I thank you for entrusting me with the editorship of the JCMR as I begin my 4th year as your editor-in-chief. It has been a tremendous experience for me and the opportunity to review manuscripts that reflect the best in our field remains a great joy and highlight of my week!
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Affiliation(s)
- Warren J Manning
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
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24
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Ma KF, Kleiss SF, Schuurmann RCL, Bokkers RPH, Ünlü Ç, De Vries JPPM. A systematic review of diagnostic techniques to determine tissue perfusion in patients with peripheral arterial disease. Expert Rev Med Devices 2019; 16:697-710. [PMID: 31340684 DOI: 10.1080/17434440.2019.1644166] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Introduction: Peripheral arterial disease (PAD) may cause symptoms due to impaired tissue perfusion of the lower extremity. So far, assessment of PAD is mainly performed by determination of stenosis or occlusion in the large arteries and does not focus on microcirculation. Several diagnostic techniques have been recently introduced that may enable tissue perfusion measurements in the lower limb; however, most have not yet been implemented in clinical daily practice. This systematic review provides an overview of these diagnostic techniques and their ability to accurately detect PAD by peripheral tissue perfusion. Areas covered: A literature search was performed for articles that described a diagnostic technique to determine tissue perfusion in patients with known PAD compared with healthy controls. Expert opinion: So far, transcutaneous oxygen measurements are most often used to measure tissue oxygenation in PAD patients, but evidence seems too low to define this technique as a gold standard, and implementing this technique for home monitoring is difficult. New potentially suitable diagnostic tests should be non-invasive, contact-free, and quick. Further research is needed for all of these techniques before broad implementation in clinical use is justified, in hospital, and for home monitoring.
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Affiliation(s)
- Kirsten F Ma
- a Department of Surgery, Division of Vascular Surgery, University Medical Center Groningen, University of Groningen , Groningen , The Netherlands
| | - Simone F Kleiss
- a Department of Surgery, Division of Vascular Surgery, University Medical Center Groningen, University of Groningen , Groningen , The Netherlands
| | - Richte C L Schuurmann
- a Department of Surgery, Division of Vascular Surgery, University Medical Center Groningen, University of Groningen , Groningen , The Netherlands
| | - Reinoud P H Bokkers
- b Department of Vascular Surgery, Noordwest Hospital Group , Alkmaar , The Netherlands
| | - Çagdas Ünlü
- c Department of Radiology, Medical Imaging Center, University Medical Center Groningen, University of Groningen , Groningen , The Netherlands
| | - Jean-Paul P M De Vries
- a Department of Surgery, Division of Vascular Surgery, University Medical Center Groningen, University of Groningen , Groningen , The Netherlands
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25
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Leung DG. Advancements in magnetic resonance imaging-based biomarkers for muscular dystrophy. Muscle Nerve 2019; 60:347-360. [PMID: 31026060 DOI: 10.1002/mus.26497] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2019] [Indexed: 12/26/2022]
Abstract
Recent years have seen steady progress in the identification of genetic muscle diseases as well as efforts to develop treatment for these diseases. Consequently, sensitive and objective new methods are required to identify and monitor muscle pathology. Magnetic resonance imaging offers multiple potential biomarkers of disease severity in the muscular dystrophies. This Review uses a pathology-based approach to examine the ways in which MRI and spectroscopy have been used to study muscular dystrophies. Methods that have been used to quantitate intramuscular fat, edema, fiber orientation, metabolism, fibrosis, and vascular perfusion are examined, and this Review describes how MRI can help diagnose these conditions and improve upon existing muscle biomarkers by detecting small increments of disease-related change. Important challenges in the implementation of imaging biomarkers, such as standardization of protocols and validating imaging measurements with respect to clinical outcomes, are also described.
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Affiliation(s)
- Doris G Leung
- Center for Genetic Muscle Disorders, Hugo W. Moser Research Institute at Kennedy Krieger Institute, 716 North Broadway, Room 411, Baltimore, Maryland, 21205.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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26
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Conlin CC, Layec G, Hanrahan CJ, Hu N, Mueller MT, Lee VS, Zhang JL. Exercise-stimulated arterial transit time in calf muscles measured by dynamic contrast-enhanced magnetic resonance imaging. Physiol Rep 2019; 7:e13978. [PMID: 30648355 PMCID: PMC6333626 DOI: 10.14814/phy2.13978] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 12/15/2018] [Accepted: 12/18/2018] [Indexed: 12/21/2022] Open
Abstract
The primary goal of this study was to evaluate arterial transit time (ATT) in exercise-stimulated calf muscles as a promising indicator of muscle function. Following plantar flexion, ATT was measured by dynamic contrast-enhanced (DCE) MRI in young and elderly healthy subjects and patients with peripheral artery disease (PAD). In the young healthy subjects, gastrocnemius ATT decreased significantly (P < 0.01) from 4.3 ± 1.5 to 2.4 ± 0.4 sec when exercise load increased from 4 lbs to 16 lbs. For the same load of 4 lbs, gastrocnemius ATT was lower in the elderly healthy subjects (3.2 ± 1.1 sec; P = 0.08) and in the PAD patients (2.4 ± 1.2 sec; P = 0.02) than in the young healthy subjects. While the sensitivity of the exercise-stimulated ATT is diagnostically useful, it poses a challenge for arterial spin labeling (ASL), a noncontrast MRI method for measuring muscle perfusion. As a secondary goal of this study, we assessed the impact of ATT on ASL-measured perfusion with ASL data of multiple post labeling delays (PLDs) acquired from a healthy subject. Perfusion varied substantially with PLD in the activated gastrocnemius, which can be attributed to the ATT variability as verified by a simulation. In conclusion, muscle ATT is sensitive to exercise intensity, and it potentially reflects the functional impact of aging and PAD on calf muscles. For precise measurement of exercise-stimulated muscle perfusion, it is recommended that ATT be considered when quantifying muscle ASL data.
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Affiliation(s)
| | - Gwenael Layec
- School of Public Health and Health SciencesUniversity of Massachusetts AmherstAmherstMassachusetts
| | | | - Nan Hu
- Division of BiostatisticsDepartment of Internal MedicineUniversity of UtahSalt Lake CityUtah
| | - Michelle T. Mueller
- Division of Vascular SurgeryDepartment of Internal MedicineUniversity of UtahSalt Lake CityUtah
| | | | - Jeff L. Zhang
- Department of Radiology and Imaging SciencesUniversity of UtahSalt Lake CityUtah
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