Clinical implications of skeletal muscle blood-oxygenation-level-dependent (BOLD) MRI

Partovi, Sasan; Karimi, Sasan; Jacobi, Bjoern; Schulte, Anja‐Carina; Aschwanden, Markus; Zipp, Lisa; Lyo, John; Karmonik, Christof; Müller–Eschner, Matthias; Huegli, Rolf W.; Bongartz, G.; Bilecen, Deniz

doi:10.1007/s10334-012-0306-y

Cited by 28 publications

(32 citation statements)

References 82 publications

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“…Thus changes in T 2 * in response to an ischemia-reperfusion paradigm can serve as a relative marker of tissue oxygenation [7]. The BOLD signal originates not only from changes in blood oxygen level, it is also sensitive to changes in perfusion, cellular pH, vessel diameter, and vessel orientation [9,21,23,38-40]. It has been postulated, however, that the BOLD signal changes primarily result from changes in the concentration of deoxyhemoglobin in the capillary bed [40].…”

Section: Theorymentioning

confidence: 99%

Combined measurement of perfusion, venous oxygen saturation, and skeletal muscle T2* during reactive hyperemia in the leg

Englund

Langham

Cheng

et al. 2013

Journal of Cardiovascular Magnetic Resonance

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BackgroundThe function of the peripheral microvascular may be interrogated by measuring perfusion, tissue oxygen concentration, or venous oxygen saturation (SvO2) recovery dynamics following induced ischemia. The purpose of this work is to develop and evaluate a magnetic resonance (MR) technique for simultaneous measurement of perfusion, SvO2, and skeletal muscle T2*.MethodsPerfusion, Intravascular Venous Oxygen saturation, and T2* (PIVOT) is comprised of interleaved pulsed arterial spin labeling (PASL) and multi-echo gradient-recalled echo (GRE) sequences. During the PASL post-labeling delay, images are acquired with a multi-echo GRE to quantify SvO2 and T2* at a downstream slice location. Thus time-courses of perfusion, SvO2, and T2* are quantified simultaneously within a single scan. The new sequence was compared to separately measured PASL or multi-echo GRE data during reactive hyperemia in five young healthy subjects. To explore the impairment present in peripheral artery disease patients, five patients were evaluated with PIVOT.ResultsComparison of PIVOT-derived data to the standard techniques shows that there was no significant bias in any of the time-course-derived metrics. Preliminary data show that PAD patients exhibited alterations in perfusion, SvO2, and T2* time-courses compared to young healthy subjects.ConclusionSimultaneous quantification of perfusion, SvO2, and T2* is possible with PIVOT. Kinetics of perfusion, SvO2, and T2* during reactive hyperemia may help to provide insight into the function of the peripheral microvasculature in patients with PAD.

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Section: Theorymentioning

confidence: 99%

Combined measurement of perfusion, venous oxygen saturation, and skeletal muscle T2* during reactive hyperemia in the leg

Englund

Langham

Cheng

et al. 2013

Journal of Cardiovascular Magnetic Resonance

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“…The blood O 2 level-dependent (BOLD) contrast exists outside the brain and the resulting tissue T 2 * dependence on hemoglobin saturation can be exploited to monitor venous and/or capillary oxygenation dynamically [13,14,15,16,17]. The multifactorial dependence of BOLD makes it difficult to determine blood oxygenation quantitatively with this approach.…”

Section: Introductionmentioning

confidence: 99%

Noninvasive Estimation of Oxygen Consumption in Human Calf Muscle through Combined NMR Measurements of ASL Perfusion and T<sub>2</sub> Oxymetry

et al. 2014

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The objective of this work was to demonstrate the feasibility of measuring muscle O₂ consumption (V)O₂) noninvasively with a combination of functional nuclear magnetic resonance (NMR) imaging methods, and to verify that changes in muscle V)O₂ can be detected with a temporal resolution compatible with physiological investigation and patient ease. T₂-based oxymetry of arterial and venous blood was combined with the arterial-spin labeling (ASL)-based determination of muscle perfusion. These measurements were performed on 8 healthy volunteers under normoxic and hypoxic conditions in order to assess the sensitivity of measurements over a range of saturation values. Blood samples were drawn simultaneously and used to titrate blood T₂ measurements versus hemoglobin O₂ saturation (%HbO₂) in vitro. The in vitro calibration curve of blood T₂ fitted very well with the %HbO₂ (r²: 0.95). The in vivo venous T₂ measurements agreed well with the in vitro measurements (intraclass correlation coefficient 0.82, 95% confidence interval 0.61-0.91). Oxygen extraction at rest decreased in the calf muscles subjected to hypoxia (p = 0.031). The combination of unaltered muscle perfusion and pinched arteriovenous O₂ difference (p = 0.038) pointed towards a reduced calf muscle V)O₂ during transient hypoxia (p = 0.018). The results of this pilot study confirmed that muscle O₂ extraction and V)O₂ can be estimated noninvasively using a combination of functional NMR techniques. Further studies are needed to confirm the usefulness in a larger sample of volunteers and patients. i 2014 S. Karger AG, Basel

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“…Reactive hyperemia offers a more consistent and easily reproducible method to obtain T2* signal intensity changes when compared with functional hyperemia. 53 BOLD measurements can be taken through a single section of the calf at rest, after thigh cuff inflation (arterial occlusion), during reactive hyperemia and during return to baseline. Figure 7 depicts the typical T2* values obtained before and after cuff inflation and illustrates the parameters that can be measured using the curve to determine oxygenation/perfusion, including minimum T2* during ischemia (T2*min), TTP, and maximum T2* (T2*max) during reactive hyperemia.…”

Section: Arterial Spin Labeling Mrimentioning

confidence: 99%

Assessment of Tissue Perfusion in the Lower Limb

Bajwa

Wesolowski

Patel

et al. 2014

Circ: Cardiovascular Imaging

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Downloaded from Bajwa et al Assessment of Lower Limb Perfusion 837when compared with normal limbs and cannot quantify the severity of perfusion deficit. 12 More recent studies show that LDF is a good discriminator of skin flap perfusion and can predict the likelihood of healing after limb amputation.13 LDI is used in preclinical animal models of limb ischemia (eg, the murine hindlimb ischemia model) for high throughput testing of interventions, including angiogenic therapies. The technique allows longitudinal acquisition of data but is limited by motion artifact, ambient temperature variations, and perfusion measurements, which are weighted toward the larger vessels that are shallow and reside on the surface of the limb musculature. 14 Transcutaneous Oxygen PressureThe measurement of transcutaneous oxygen pressure (TcPo 2 ) is a noninvasive technique that allows longitudinal assessment of local oxygen diffusion from the capillary bed through the skin epidermis and provides an indication of the amount of oxygen delivered to the tissue. TcPo 2 measurements can reflect the severity of PAD, 15 assess ulcer healing potential, 16 and determine the optimal level for limb amputation. 17 A TcPo 2 <20 to 30 mm Hg is consistent with CLI, 2,15,18 and levels <40 mm Hg are associated with poor healing after amputation. 18 Inhalation of 100% oxygen would normally result in TcPo 2 >100 mm Hg, but in patients with CLI the TcPo 2 does not rise >30 mm Hg. 18 Oxygen therapy resulting in <10 mm Hg rise in limb TcPo 2 is associated with an >60% chance of an amputation at that level not healing. 18 A rise of >40 mm Hg in TcPo 2 after limb revascularization is considered significant and increases the chances of tissue healing. 15,18 TcPo 2 measurements vary in different tissues and under different physiological conditions. Barriers to diffusion, such as edema, increased oxygen consumption secondary to inflammation, and vasoconstriction, may lead to falsely low TcPo 2 readings falsely. Readings are also affected by temperature, with a 1°C reduction in the thermistor temperature resulting in a 2% to 3% lower TcPo 2 reading. 18 Indocyanine Green Fluorescence AngiographyThis technique has been used for many years to image retinal vessels, 19 and more recently in the assessment of microanastomoses in surgical flap reconstruction surgery, detection of arteriovenous malformations, and measurement of hepatic blood flow. 20 Indocyanine green is a fluorescent dye that is activated by near-infrared laser light at ≈780 nm. 21 This allows a penetrance of 3 mm from the surface of the skin to assess the subdermal microcirculation. 20,22 A semiquantitative measure of perfusion is obtained by measuring pixel fluorescence intensity in different areas of the image from the limb. Perfusion measured by indocyanine green fluorescence angiography correlates with LDI in the hindlimb ischemia model 23 and predicts the likelihood of amputation healing in man. 21 This technique can identify patients with peripheral arterial occlusions who have extensive collater...

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Clinical implications of skeletal muscle blood-oxygenation-level-dependent (BOLD) MRI

Cited by 28 publications

References 82 publications

Combined measurement of perfusion, venous oxygen saturation, and skeletal muscle T2* during reactive hyperemia in the leg

Combined measurement of perfusion, venous oxygen saturation, and skeletal muscle T2* during reactive hyperemia in the leg

Noninvasive Estimation of Oxygen Consumption in Human Calf Muscle through Combined NMR Measurements of ASL Perfusion and T<sub>2</sub> Oxymetry

Assessment of Tissue Perfusion in the Lower Limb

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