Accurate <i>T</i><sub>1</sub> mapping for oxygen‐enhanced MRI in the mouse lung using a segmented inversion‐recovery ultrashort echo‐time sequence

Żurek, Magdalena; Johansson, Edvin; Risse, F.; Alamidi, Daniel; Olsson, Lars; Hockings, Paul D.

doi:10.1002/mrm.24876

Cited by 18 publications

(29 citation statements)

References 27 publications

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“…B: Theoretical and simulated optimum flip angles with and without decay during the RF pulses to maximize short T2 signals as a function of number of spokes N. Also shown are three theoretical curves: The dotted black line corresponds to the first part of Eq. [4], while the dotted cyan line corresponds to the second approximation in Eq. [4].…”

Section: Short T2 Optimizationmentioning

confidence: 99%

“…[4], while the dotted cyan line corresponds to the second approximation in Eq. [4]. Finally, the dotted green line shows the results of the transcendental equation from setting the derivative of S i in Eq.…”

Section: Short T2 Optimizationmentioning

confidence: 99%

“…This can often be very scan time inefficient due to the large number of spokes that need to be collected in UTE imaging. In this work we explore the use of several k‐space spokes after the application of a single inversion pulse to achieve longer T2 signal suppression using a three‐dimensional (3D) UTE (3D Cones) sequence. Theoretical calculations and simulations were used to optimize sequence parameters such as the inversion time (TI) and the flip angle (θ).…”

Section: Introductionmentioning

confidence: 99%

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UTE imaging with simultaneous water and fat signal suppression using a time-efficient multispoke inversion recovery pulse sequence

2015

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Purpose The long repetition time and inversion time with inversion recovery preparation ultrashort echo (UTE) often causes prohibitively long scan times. We present an optimized method for long T2 signal suppression in which several k-space spokes are acquired after each inversion preparation. Theory and Methods Using Bloch equations the sequence parameters such as TI and flip angle were optimized to suppress the long T2 fat and water signals and to maximize short T2 contrast. Volunteer imaging was performed on a healthy male volunteer. Inversion recovery preparation was performed using a Silver-Hoult adiabatic inversion pulses together with a three-dimensional (3D) UTE (3D Cones) acquisition. Results The theoretical signal curves generally agreed with the experimentally measured region of interest curves. The multispoke inversion recovery method showed good muscle and fatty bone marrow suppression, and highlighted short T2 signals such as these from the femoral and tibial cortex. Conclusion Inversion recovery 3D UTE imaging with multiple spoke acquisitions can be used to effectively suppress long T2 signals and highlight short T2 signals within clinical scan times. Theoretical modeling can be used to determine sequence parameters to optimize long T2 signal suppression and maximize short T2 signals. Experimental results on a volunteer confirmed the theoretical predictions.

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Section: Short T2 Optimizationmentioning

confidence: 99%

Section: Short T2 Optimizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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UTE imaging with simultaneous water and fat signal suppression using a time-efficient multispoke inversion recovery pulse sequence

2015

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“…Oxygen‐enhanced MRI (OE‐MRI) takes advantage of the physical properties of molecular oxygen resident in the lung. When dissolved in blood, molecular oxygen shortens the T 1 ‐relaxation time of the pulmonary venous blood, and this translates to an increase in MR signal that is dependent upon the presence of O 2 itself. To acquire such images, subjects first breathe in room air (21% oxygen) for imaging, then 100% oxygen for a short period of time and then room air again to generate difference maps.…”

Section: Magnetic Resonance Imagingmentioning

confidence: 99%

This is what COPD looks like

2015

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Despite decades of research, and the growing healthcare and societal burden of chronic obstructive pulmonary disease (COPD), therapeutic COPD breakthroughs have not occurred. Sub-optimal COPD patient phenotyping, an incomplete understanding of COPD pathogenesis and a scarcity of sensitive tools that provide patient-relevant intermediate endpoints likely all play a role in the lack of new, efficacious COPD interventions. In other words, COPD patients are still diagnosed based on the presence of persistent airflow limitation measured using spirometry. Spirometry measurements reflect the global sum of all the different possible COPD pathologies and perhaps because of this, we lose sight of the different contributions of airway and parenchymal abnormalities. With recent advances in thoracic X-ray computed tomography (CT) and magnetic resonance imaging (MRI), lung structure and function abnormalities may be regionally identified and measured.These imaging endpoints may serve as biomarkers of COPD that can be used to better phenotype patients. Therefore, here we review novel CT and MRI measurements that help reveal COPD phenotypes and what COPD really 'looks' like, beyond spirometric indices. We discuss MR and CT imaging approaches for generating reproducible and sensitive measurements of COPD phenotypes related to pulmonary ventilation and perfusion as well as airway and parenchyma anatomical and morphological features. These measurements may provide a way to advance the development and testing of new COPD interventions and therapies.

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“…Several centers have also used ultra-short echo time for OE-measurements, to address the inherently low MR-signal [14–16]. However, although OE-MRI has been applied to study disease and healthy controls [15,17], no previous work has described the effect with respect to age and sex in a healthy cohort.…”

Section: Introductionmentioning

confidence: 99%

The change of longitudinal relaxation rate in oxygen enhanced pulmonary MRI depends on age and BMI but not diffusing capacity of carbon monoxide in healthy never-smokers

et al. 2017

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ObjectiveOxygen enhanced pulmonary MRI is a promising modality for functional lung studies and has been applied to a wide range of pulmonary conditions. The purpose of this study was to characterize the oxygen enhancement effect in the lungs of healthy, never-smokers, in light of a previously established relationship between oxygen enhancement and diffusing capacity of carbon monoxide in the lung (DL,CO) in patients with lung disease.MethodsIn 30 healthy never-smoking volunteers, an inversion recovery with gradient echo read-out (Snapshot-FLASH) was used to quantify the difference in longitudinal relaxation rate, while breathing air and 100% oxygen, ΔR1, at 1.5 Tesla. Measurements were performed under multiple tidal inspiration breath-holds.ResultsIn single parameter linear models, ΔR1 exhibit a significant correlation with age (p = 0.003) and BMI (p = 0.0004), but not DL,CO (p = 0.33). Stepwise linear regression of ΔR1 yields an optimized model including an age-BMI interaction term.ConclusionIn this healthy, never-smoking cohort, age and BMI are both predictors of the change in MRI longitudinal relaxation rate when breathing oxygen. However, DL,CO does not show a significant correlation with the oxygen enhancement. This is possibly because oxygen transfer in the lung is not diffusion limited at rest in healthy individuals. This work stresses the importance of using a physiological model to understand results from oxygen enhanced MRI.

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Accurate T₁ mapping for oxygen‐enhanced MRI in the mouse lung using a segmented inversion‐recovery ultrashort echo‐time sequence

Abstract: Segmented inversion-recovery ultrashort echo-time provides accurate, high resolution T(1) mapping of the lung parenchyma.

Cited by 18 publications

References 27 publications

UTE imaging with simultaneous water and fat signal suppression using a time-efficient multispoke inversion recovery pulse sequence

UTE imaging with simultaneous water and fat signal suppression using a time-efficient multispoke inversion recovery pulse sequence

This is what COPD looks like

The change of longitudinal relaxation rate in oxygen enhanced pulmonary MRI depends on age and BMI but not diffusing capacity of carbon monoxide in healthy never-smokers

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Accurate T1 mapping for oxygen‐enhanced MRI in the mouse lung using a segmented inversion‐recovery ultrashort echo‐time sequence

Abstract: Segmented inversion-recovery ultrashort echo-time provides accurate, high resolution T(1) mapping of the lung parenchyma.

Cited by 18 publications

References 27 publications

UTE imaging with simultaneous water and fat signal suppression using a time-efficient multispoke inversion recovery pulse sequence

UTE imaging with simultaneous water and fat signal suppression using a time-efficient multispoke inversion recovery pulse sequence

This is what COPD looks like

The change of longitudinal relaxation rate in oxygen enhanced pulmonary MRI depends on age and BMI but not diffusing capacity of carbon monoxide in healthy never-smokers

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Accurate T₁ mapping for oxygen‐enhanced MRI in the mouse lung using a segmented inversion‐recovery ultrashort echo‐time sequence