Tiny golden angle ultrashort echo‐time lung imaging in mice

Balasch, Anke; Metze, Patrick; Li, Hao; Rottbauer, Wolfgang; Abaei, Alireza; Rasche, Volker

doi:10.1002/nbm.4591

Cited by 3 publications

(4 citation statements)

References 58 publications

(111 reference statements)

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“…Guo et al 46 used 7 T field strength, a spatial resolution of 0.47 × 0.47 × 0.47 mm 3 and six different echo times, measuring a T 2 * of 395 μs. Balasch 47 measured 200 μs at 11.7 T using a spatial resolution of 0.2 × 0.2 × 0.2 mm 3 , 10 echo times, and local noise measurement.…”

Section: Discussionmentioning

confidence: 99%

Assessment of iron nanoparticle distribution in mouse models using ultrashort‐echo‐time MRI

et al. 2022

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Microscopic magnetic field inhomogeneities caused by iron deposition or tissue-air interfaces may result in rapid decay of transverse magnetization in magnetic resonance imaging (MRI). The aim of this study is to detect and quantify the distribution of iron-based nanoparticles in mouse models applying ultrashort echo-time (UTE) sequences in tissues exhibiting extremely fast transverse relaxation. In 24 C57BL/6 mice (2 controls), suspensions containing either non-oxidic Fe or AuFeOx nanoparticles were injected into the tail vein at two doses (200 g and 600 g per mouse). Mice underwent MRI using a UTE sequence at 4.7T field strength with five different echo-times between 100 s and 5000 s. Transverse relaxation times T2* were computed for the lung, liver, and spleen by mono-exponential fitting. In UTE imaging, the MRI signal could reliably be detected even in liver parenchyma exhibiting the highest deposition of nanoparticles. In animals treated with Fe nanoparticles (600 g per mouse), the relaxation time substantially decreased in the liver (3418±1534 s (control) vs. 228±67 s), the spleen (2170±728 s vs. 299±97 s), and the lungs (663±101 s vs. 413±99 s). The change in transverse relaxation was dependent on the amount and composition of the nanoparticles. By pixel-wise curve fitting, T2* maps were calculated showing nanoparticle distribution. In conclusion, UTE sequences may be used to assess and quantify nanoparticle distribution in tissues exhibiting ultra-fast signal decay in MRI.

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Section: Discussionmentioning

confidence: 99%

Assessment of iron nanoparticle distribution in mouse models using ultrashort‐echo‐time MRI

et al. 2022

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“…The feasibility of tyGA UTE for imaging lung function in mice was first demonstrated by Balasch et al 41 with examples of anatomical, ventilation, and contrast‐enhanced imaging in healthy animals. From a practical perspective, these motion‐resolved UTE images could be used to assess molecular parameters of the lungs via changes in tissue relaxation caused by an injection of a contrast agent.…”

Section: Introductionmentioning

confidence: 99%

“…It is worth noting that the concept of tyGA could be readily extended to 3D imaging, which together with recent advances in nonuniform k-space sampling could constitute a time-efficient and powerful tool for various applications of UTE imaging. [38][39][40] The feasibility of tyGA UTE for imaging lung function in mice was first demonstrated by Balasch et al 41 with examples of anatomical, ventilation, and contrast-enhanced imaging in healthy animals. From a practical perspective, these motion-resolved UTE images could be used to assess molecular parameters of the lungs via changes in tissue relaxation caused by an injection of a contrast agent.…”

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confidence: 99%

Retrospectively gated ultrashort‐echo‐time MRI T₁ mapping reveals compromised pulmonary microvascular NO‐dependent function in a murine model of acute lung injury

Kwiatkowski,

Czyzynska‐Cichon,

Tielemans

et al. 2024

NMR in Biomedicine

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This study sought to develop noninvasive, in vivo imaging schemes that allow for quantitative assessment of pulmonary microvascular functional status based on the combination of pulmonary T1 mapping and dynamic contrast‐enhanced (DynCE) imaging.Ultrashort‐echo‐time (UTE) imaging at 9.4 T of lung parenchyma was performed. Retrospective gating was based on modulation of the first point in each recorded spoke. T1 maps were obtained using a series of five consecutive images with varying RF angles and analyzed with the variable flip angle approach. The obtained mean T1 lung value of 1078 ± 38 ms correlated well with previous reports. Improved intersession variability was observed, as evident from a decreased standard deviation of motion‐resolved T1 mapping (F‐test = 0.051). Animals received lipopolysaccharide (LPS) and were imaged at t = 2, 6, and 12 h after administration. The nitric oxide (NO)‐dependent function was assessed according to changes in lung T1 after L‐NAME injection, while microvascular perfusion and oxidant stress were assessed with contrast‐enhanced imaging after injection of gadolinium or 3‐carbamoyl‐proxyl nitroxide radical, respectively.Retrospectivel gated UTE allowed robust, motion‐compensated imaging that could be used for T1 mapping of lung parenchyma. Changes in lung T1 after L‐NAME injection indicated that LPS induced overproduction of NO at t = 2 and 6 h after LPS, but NO‐dependent microvascular function was impaired at t = 12 h after LPS. DynCE imaging at t = 6 h after LPS injection revealed decreased microvascular perfusion, with increased vascular permeability and oxidant stress.MRI allows to visualize and quantify lung microvascular NO‐dependent function and its concomitant impairment during acute respiratory distress syndrome development with high sensitivity. UTE T1 mapping appears to be sensitive and useful in probing pulmonary microvascular functional status.

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“…For providing high-fidelity images of lung function, Fischer et al (29) have introduced SElfgated Non-Contrast-Enhanced FUnctional Lung imaging (SENCEFUL), which combines respiratory and cardiac self-gated imaging with subsequent FD for ventilation and perfusion assessment (29). Recently it has been shown that a single free-breathing (FB) data acquisition combining UTE readouts with tyGA encoding schemes ( 19) is capable of providing the aforementioned function parameters of the lung from a single FB scan (30).…”

Section: Introductionmentioning

confidence: 99%

Reproducibility of functional lung parameters derived from free-breathing non-contrast-enhanced 2D ultrashort echo-time

Yang¹,

Metze²,

Balasch³

et al. 2022

Quant Imaging Med Surg

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Background: Imaging the lung parenchyma with magnetic resonance imaging (MRI) is challenging due to cardiac and respiratory motion, the low proton density and short T 2 * relaxation time, and therefore not well established in the clinical routine. As a further step in facilitating lung MRI for longitudinal monitoring, this study aimed to assess the reproducibility of 2D ultrashort echo time (UTE)-derived lung function parameters in healthy subjects.Methods: In this study, a 2D UTE technique was combined with tiny golden angle (tyGA) ordering. Data were acquired either during breath-holds (BH) or continuously during free-breathing (FB) at a field strength of 3T. Retrospective self-gating (image-and k-space-based) was used to reconstruct respiratory and cardiac multistage images from the FB acquisitions. The reproducibility of functional lung parameters derived from BH and FB acquisitions was assessed for three independent examinations (M1-3). M1 and M2 were acquired within 2h, whereas M3 was acquired at least 14d after M1/2. Different respiratory and cardiac phases were reconstructed for three coronal slices. Quantitative analysis including proton fraction (f P ), apparent signal-tonoise ratio (apparent SNR), fractional ventilation (FV), and perfusion (f) was performed by two independent observers, and inter-measurement and inter-observer repeatability were assessed.Results: All scans could be performed successfully in all volunteers. Intraclass correlation coefficients (ICC) of inter-measurement and inter-observer variability, and Bland-Altman analysis showed good to very good reproducibility. Larger breathing amplitudes were observed in the BH acquisitions, which also showed lower reproducibility when compared with the FB acquisitions. For the FB approach, the ICC ranged between 0.70 and 0.98 for all measurements, and ranged between 0.86 and 0.97 for the two observers. No bias or significant differences were observed between the three measurements or the two observers in healthy volunteers. Conclusions:The study proves the feasibility of FB 2D tyGA UTE for lung imaging. Functional parameters derived from FB acquisitions are reproducible in healthy volunteers, allowing for further investigation of this technique in patients with various underlying diseases.

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Tiny golden angle ultrashort echo‐time lung imaging in mice

Cited by 3 publications

References 58 publications

Assessment of iron nanoparticle distribution in mouse models using ultrashort‐echo‐time MRI

Assessment of iron nanoparticle distribution in mouse models using ultrashort‐echo‐time MRI

Retrospectively gated ultrashort‐echo‐time MRI T₁ mapping reveals compromised pulmonary microvascular NO‐dependent function in a murine model of acute lung injury

Reproducibility of functional lung parameters derived from free-breathing non-contrast-enhanced 2D ultrashort echo-time

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Tiny golden angle ultrashort echo‐time lung imaging in mice

Cited by 3 publications

References 58 publications

Assessment of iron nanoparticle distribution in mouse models using ultrashort‐echo‐time MRI

Assessment of iron nanoparticle distribution in mouse models using ultrashort‐echo‐time MRI

Retrospectively gated ultrashort‐echo‐time MRI T1 mapping reveals compromised pulmonary microvascular NO‐dependent function in a murine model of acute lung injury

Reproducibility of functional lung parameters derived from free-breathing non-contrast-enhanced 2D ultrashort echo-time

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Retrospectively gated ultrashort‐echo‐time MRI T₁ mapping reveals compromised pulmonary microvascular NO‐dependent function in a murine model of acute lung injury