T2<sup>*</sup> Measurements of 3-T MRI With Ultrashort TEs: Capabilities of Pulmonary Function Assessment and Clinical Stage Classification in Smokers

Ohno, Yoshiharu; Koyama, Hisanobu; Yoshikawa, Takeshi; Matsumoto, Keiko; Takahashi, Masaya; Cauteren, Marc Van; Sugimura, Kazuro

doi:10.2214/ajr.10.5350

Cited by 65 publications

(107 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although advances continue with techniques such as ultrashort echo time (UTE) imaging of the lung parenchyma (3), conventional proton-based MRI is at a fundamental disadvantage for pulmonary applications because it cannot directly image the lung airspaces. This disadvantage of proton MRI can be overcome by turning to a gaseous contrast agent, such as the noble gas helium-3 ( 3 He) or xenon-129 ( 129 Xe), which upon inhalation permits direct visualization of lung airspaces in an MR image (4–8).…”

mentioning

confidence: 99%

Hyperpolarized ¹²⁹Xe MRI of the human lung

Mugler

Altes

2013

Magnetic Resonance Imaging

318

445

View full text Add to dashboard Cite

By permitting direct visualization of the airspaces of the lung, MR imaging using hyperpolarized gases provides unique strategies for evaluating pulmonary structure and function. Although the vast majority of research in humans has been performed using hyperpolarized 3He, recent contraction in the supply of 3He and consequent increases in price have turned attention to the alternative agent, hyperpolarized 129Xe. Compared to 3He, 129Xe yields reduced signal due to its smaller magnetic moment. Nonetheless, taking advantage of advances in gas-polarization technology, recent studies in humans using techniques for measuring ventilation, diffusion, and partial pressure of oxygen have demonstrated results for hyperpolarized 129Xe comparable to those previously demonstrated using hyperpolarized 3He. In addition, xenon has the advantage of readily dissolving in lung tissue and blood following inhalation, which makes hyperpolarized 129Xe particularly attractive for exploring certain characteristics of lung function, such as gas exchange and uptake, which cannot be accessed using 3He. Preliminary results from methods for imaging 129Xe dissolved in the human lung suggest that these approaches will provide new opportunities for quantifying relationships among gas delivery, exchange, and transport, and thus show substantial potential to broaden our understanding of lung disease. Finally, recent changes in the commercial landscape of the hyperpolarized-gas field now make it possible for this innovative technology to move beyond the research lab.

show abstract

mentioning

confidence: 99%

Hyperpolarized ¹²⁹Xe MRI of the human lung

Mugler

Altes

2013

Magnetic Resonance Imaging

318

445

View full text Add to dashboard Cite

show abstract

“…The first studies employing UTE methods reported that the tissue density was related to MR signal 109 and T 2 *. UTE MRI was also used to measure signal intensity and T 2 * in emphysema 110 and showed good correlations with histological measurements while T 2 * correlated with pulmonary function measurements 111 and pulmonary signal intensity was related to tissue density, pulmonary function and CT density measurements. 108 Very recently methods have been developed that exploit optimized 112 and so-called zero echo time (ZTE) 113 approaches and this has resulted in excellent, MR image quality and signal in pulmonary images that is very similar to CT. Another method for measuring regional lung function, involves using inhaled oxygen in combination with 1 H MRI 114 and this exploits the alteration of lung tissue 1 H relaxation times by molecular O 2 .…”

Section: Pulmonary Mri Measurements Of Copdmentioning

confidence: 99%

Pulmonary CT and MRI phenotypes that help explain chronic pulmonary obstruction disease pathophysiology and outcomes

Hoffman

Lynch

Barr

et al. 2015

Magnetic Resonance Imaging

View full text Add to dashboard Cite

Pulmonary X-ray computed tomographic (CT) and magnetic resonance imaging (MRI) research and development has been motivated, in part, by the quest to sub-phenotype common chronic lung diseases such as chronic obstructive pulmonary disease (COPD). For thoracic CT and MRI, the main COPD research tools, disease biomarkers are being validated that go beyond anatomy and structure to include pulmonary functional measurements such as regional ventilation, perfusion and inflammation. In addition, there has also been a drive to improve spatial and contrast resolution while at the same time reducing or eliminating radiation exposure. Therefore, this review focuses on our evolving understanding of patient-relevant and clinically-important COPD endpoints and how current and emerging MRI and CT tools and measurements may be exploited for their identification, quantification and utilization. Since reviews of the imaging physics of pulmonary CT and MRI and reviews of other COPD imaging methods were previously published and well-summarized, we focus on the current clinical challenges in COPD and the potential of newly emerging MR and CT imaging measurements to address them. Here we summarize MRI and CT imaging methods and their clinical translation for generating reproducible and sensitive measurements of COPD related to pulmonary ventilation and perfusion as well as parenchyma morphology. The key clinical problems in COPD provide an important framework in which pulmonary imaging needs to rapidly move in order to address the staggering burden, costs as well as the mortality and morbidity associated with COPD.

show abstract

“…The use of detailed gradient echo signal decays to estimate proton density, and thus lung water content (35), may have important diagnostic implications in a number of diseases, including COPD and cystic fibrosis. Indeed, Ohno et al demonstrated the feasibility of making ultra-short TE gradient echo acquisitions (0.2 ms to 4.7 ms) even at 3 T to measure T 2 * in smokers, potentially offering an assessment of clinical stage classification (22). Theilmann et al stressed the importance of the inflationary state of the lung in making T 2 * and associated lung water density measurements at 1.5 T (21), while Yu et al more recently measured T 2 * in lung parenchyma at 1.5 T and 3 T, pointing out that normal free breathing has a small effect on the T 2 * values compared to the full inspiration/expiration extremes (23).…”

Section: Relaxation Properties Of Lung Tissue From Imaging Studiesmentioning

confidence: 99%

Lung parenchymal signal intensity in MRI: A technical review with educational aspirations regarding reversible versus irreversible transverse relaxation effects in common pulse sequences

Mulkern

Haker

Mamata

et al. 2014

Concepts Magnetic Resonance

View full text Add to dashboard Cite

Lung parenchyma is challenging to image with proton MRI. The large air space results in ~l/5th as many signal-generating protons compared to other organs. Air/tissue magnetic susceptibility differences lead to strong magnetic field gradients throughout the lungs and to broad frequency distributions, much broader than within other organs. Such distributions have been the subject of experimental and theoretical analyses which may reveal aspects of lung microarchitecture useful for diagnosis. Their most immediate relevance to current imaging practice is to cause rapid signal decays, commonly discussed in terms of short T2* values of 1 ms or lower at typical imaging field strengths. Herein we provide a brief review of previous studies describing and interpreting proton lung spectra. We then link these broad frequency distributions to rapid signal decays, though not necessarily the exponential decays generally used to define T2* values. We examine how these decays influence observed signal intensities and spatial mapping features associated with the most prominent torso imaging sequences, including spoiled gradient and spin echo sequences. Effects of imperfect refocusing pulses on the multiple echo signal decays in single shot fast spin echo (SSFSE) sequences and effects of broad frequency distributions on balanced steady state free precession (bSSFP) sequence signal intensities are also provided. The theoretical analyses are based on the concept of explicitly separating the effects of reversible and irreversible transverse relaxation processes, thus providing a somewhat novel and more general framework from which to estimate lung signal intensity behavior in modern imaging practice.

show abstract

T2^* Measurements of 3-T MRI With Ultrashort TEs: Capabilities of Pulmonary Function Assessment and Clinical Stage Classification in Smokers

Abstract: MRI with ultrashort TEs is potentially as useful as quantitatively assessed MDCT for pulmonary function loss assessment and clinical stage classification of COPD in smokers.

Cited by 65 publications

References 30 publications

Hyperpolarized ¹²⁹Xe MRI of the human lung

Hyperpolarized ¹²⁹Xe MRI of the human lung

Pulmonary CT and MRI phenotypes that help explain chronic pulmonary obstruction disease pathophysiology and outcomes

Lung parenchymal signal intensity in MRI: A technical review with educational aspirations regarding reversible versus irreversible transverse relaxation effects in common pulse sequences

Contact Info

Product

Resources

About

T2* Measurements of 3-T MRI With Ultrashort TEs: Capabilities of Pulmonary Function Assessment and Clinical Stage Classification in Smokers

Abstract: MRI with ultrashort TEs is potentially as useful as quantitatively assessed MDCT for pulmonary function loss assessment and clinical stage classification of COPD in smokers.

Cited by 65 publications

References 30 publications

Hyperpolarized 129Xe MRI of the human lung

Hyperpolarized 129Xe MRI of the human lung

Pulmonary CT and MRI phenotypes that help explain chronic pulmonary obstruction disease pathophysiology and outcomes

Lung parenchymal signal intensity in MRI: A technical review with educational aspirations regarding reversible versus irreversible transverse relaxation effects in common pulse sequences

Contact Info

Product

Resources

About

T2^* Measurements of 3-T MRI With Ultrashort TEs: Capabilities of Pulmonary Function Assessment and Clinical Stage Classification in Smokers

Hyperpolarized ¹²⁹Xe MRI of the human lung

Hyperpolarized ¹²⁹Xe MRI of the human lung