“…The superiority of the UTE over the T2‐TSE sequence for the determination of lung density is in line with the findings of Zeimpekis et al 17 Here, in an age cohort similar to this study, an improved representation of lung density was obtained in UTE compared with T2‐TSE 17 . The lung density as measured in the UTE also corresponds to the severity of lung involvement in cystic fibrosis, for example, and can be automatically quantified volumetrically, and thus fairly objectively 18 …”
Section: Discussionsupporting
confidence: 90%
“…17 The lung density as measured in the UTE also corresponds to the severity of lung involvement in cystic fibrosis, for example, and can be automatically quantified volumetrically, and thus fairly objectively. 18 The merits of this study, which involves a mixed pediatric collective, are highlighted in the review of the literature: Studies with a 3D UTE in free breathing are focused, to our knowledge, exclusively on the visualization of micronodules, nodules, masses, as well as F I G U R E 7 Pleural effusion in an 11-year-old girl after metastasectomy for alveolar rhabdomyosarcoma (A) UTE shows the effusion compared with (B) T2-TSE with low signal intensity (white arrow). Small effusions may therefore be missed in the UTE.…”
Objectives: Magnetic resonance imaging (MRI) of the lungs is challenging for several reasons, mainly due to the respiratory motion, low proton density, and rapid T2* decay. Recent MR sequences with ultrashort TE (UTE) coupled with respiratory compensation promise to overcome these obstacles. So far, there are very few studies on the relevance of these sequences in children. The aim of the study was to compare the diagnostic value of a respiratory-self-gated three-dimensional UTE sequence versus a conventional respiratory-triggered T2-weighted turbo spin echo (T2-TSE) sequence in a pediatric collective.Study Design: Seventy-one patients between 0 and 18 years of age, who were scheduled for a thoracic MRI based on diverse clinical indications, were examined on a 3T MRI system. The UTE and T2-TSE sequences were evaluated by two readers regarding quality features and visualization of eight common pathology patterns.
Results:The image quality of both sequences was equally high, with UTE depicting pleural and central bronchi more clearly. In pathologies, UTE was superior to T2-TSE for so-called "MR-negative pathologies", significant for air trapping, and in tendency for bullae and cysts. In all remaining pathologies, T2-TSE proved to be at least equivalent to UTE.Conclusions: At present, UTE cannot serve as a universal replacement for conventional T2-TSE for all pathologies. It yields, however, a substantial benefit in the context of hyperinflation, emphysema, cysts, or pathologies of the bronchial system.
“…The superiority of the UTE over the T2‐TSE sequence for the determination of lung density is in line with the findings of Zeimpekis et al 17 Here, in an age cohort similar to this study, an improved representation of lung density was obtained in UTE compared with T2‐TSE 17 . The lung density as measured in the UTE also corresponds to the severity of lung involvement in cystic fibrosis, for example, and can be automatically quantified volumetrically, and thus fairly objectively 18 …”
Section: Discussionsupporting
confidence: 90%
“…17 The lung density as measured in the UTE also corresponds to the severity of lung involvement in cystic fibrosis, for example, and can be automatically quantified volumetrically, and thus fairly objectively. 18 The merits of this study, which involves a mixed pediatric collective, are highlighted in the review of the literature: Studies with a 3D UTE in free breathing are focused, to our knowledge, exclusively on the visualization of micronodules, nodules, masses, as well as F I G U R E 7 Pleural effusion in an 11-year-old girl after metastasectomy for alveolar rhabdomyosarcoma (A) UTE shows the effusion compared with (B) T2-TSE with low signal intensity (white arrow). Small effusions may therefore be missed in the UTE.…”
Objectives: Magnetic resonance imaging (MRI) of the lungs is challenging for several reasons, mainly due to the respiratory motion, low proton density, and rapid T2* decay. Recent MR sequences with ultrashort TE (UTE) coupled with respiratory compensation promise to overcome these obstacles. So far, there are very few studies on the relevance of these sequences in children. The aim of the study was to compare the diagnostic value of a respiratory-self-gated three-dimensional UTE sequence versus a conventional respiratory-triggered T2-weighted turbo spin echo (T2-TSE) sequence in a pediatric collective.Study Design: Seventy-one patients between 0 and 18 years of age, who were scheduled for a thoracic MRI based on diverse clinical indications, were examined on a 3T MRI system. The UTE and T2-TSE sequences were evaluated by two readers regarding quality features and visualization of eight common pathology patterns.
Results:The image quality of both sequences was equally high, with UTE depicting pleural and central bronchi more clearly. In pathologies, UTE was superior to T2-TSE for so-called "MR-negative pathologies", significant for air trapping, and in tendency for bullae and cysts. In all remaining pathologies, T2-TSE proved to be at least equivalent to UTE.Conclusions: At present, UTE cannot serve as a universal replacement for conventional T2-TSE for all pathologies. It yields, however, a substantial benefit in the context of hyperinflation, emphysema, cysts, or pathologies of the bronchial system.
“…A quantitative volumetric measurement of structural abnormalities by UTE also demonstrated clinical relevance to discriminate CF with exacerbation and to detect their longitudinal improvement after a 1-year follow-up, although PFT results were found to be stable. 35…”
Section: Automated Quantification Of Structural Abnormalitiesmentioning
confidence: 99%
“…A quantitative volumetric measurement of structural abnormalities by UTE also demonstrated clinical relevance to discriminate CF with exacerbation and to detect their longitudinal improvement after a 1-year follow-up, although PFT results were found to be stable. 35 Figure 2 3D-UTE MRI using a coronal reformation in a 32-year-old man with CF. A, Solid arrows show areas of advanced emphysema, and open arrows show normal lung parenchyma areas.…”
To assess airway and lung parenchymal damage noninvasively in cystic fibrosis (CF), chest MRI has been historically out of the scope of routine clinical imaging because of technical difficulties such as low proton density and respiratory and cardiac motion. However, technological breakthroughs have emerged that dramatically improve lung MRI quality (including signal-to-noise ratio, resolution, speed, and contrast). At the same time, novel treatments have changed the landscape of CF clinical care. In this contemporary context, there is now consensus that lung MRI can be used clinically to assess CF in a radiation-free manner and to enable quantification of lung disease severity. MRI can now achieve three-dimensional, high-resolution morphologic imaging, and beyond this morphologic information, MRI may offer the ability to sensitively differentiate active inflammation vs scarring tissue. MRI could also characterize various forms of inflammation for early guidance of treatment. Moreover, functional information from MRI can be used to assess regional, small-airway disease with sensitivity to detect small changes even in patients with mild CF. Finally, automated quantification methods have emerged to support conventional visual analyses for more objective and reproducible assessment of disease severity. This article aims to review the most recent developments of lung MRI, with a focus on practical application and clinical value in CF, and the perspectives on how these modern techniques may converge and impact patient care soon.
“…The recently developed ultrashort echo time (UTE) sequences have very short TE on the order of < 0.1 ms combined with rapid acquisition due to short TR, which makes them suitable to acquire signals from tissues with short T2/T2* relaxation times [18,[26][27][28][29]. Three-dimensional (3D) UTE techniques allow isotropic resolutions with slice thicknesses around 1 mm and, due to their numerous excitations, can be acquired during freebreathing of the patients [26][27][28][29][30][31]. As far as we know, this is the first study, which has performed a detailed analysis of a 3D UTE sequence of the lung with isotropic voxels in a paediatric oncologic population, including an objective and subjective imaging assessment.…”
Objectives
To compare the diagnostic value of ultrashort echo time (UTE) magnetic resonance imaging (MRI) for the lung versus the gold standard computed tomography (CT) and two T1-weighted MRI sequences in children.
Methods
Twenty-three patients with proven oncologic disease (14 male, 9 female; mean age 9.0 + / − 5.4 years) received 35 low-dose CT and MRI examinations of the lung. The MRI protocol (1.5-T) included the following post-contrast sequences: two-dimensional (2D) incoherent gradient echo (GRE; acquisition with breath-hold), 3D volume interpolated GRE (breath-hold), and 3D high-resolution radial UTE sequences (performed during free-breathing). Images were evaluated by considering image quality as well as distinct diagnosis of pulmonary nodules and parenchymal areal opacities with consideration of sizes and characterisations.
Results
The UTE technique showed significantly higher overall image quality, better sharpness, and fewer artefacts than both other sequences. On CT, 110 pulmonary nodules with a mean diameter of 4.9 + / − 2.9 mm were detected. UTE imaging resulted in a significantly higher detection rate compared to both other sequences (p < 0.01): 76.4% (84 of 110 nodules) for UTE versus 60.9% (67 of 110) for incoherent GRE and 62.7% (69 of 110) for volume interpolated GRE sequences. The detection of parenchymal areal opacities by the UTE technique was also significantly higher with a rate of 93.3% (42 of 45 opacities) versus 77.8% (35 of 45) for 2D GRE and 80.0% (36 of 45) for 3D GRE sequences (p < 0.05).
Conclusion
The UTE technique for lung MRI is favourable in children with generally high diagnostic performance compared to standard T1-weighted sequences as well as CT.
Key Points
• Due to the possible acquisition during free-breathing of the patients, the UTE MRI sequence for the lung is favourable in children.
• The UTE technique reaches higher overall image quality, better sharpness, and lower artefacts, but not higher contrast compared to standard post-contrast T1-weighted sequences.
• In comparison to the gold standard chest CT, the detection rate of small pulmonary nodules small nodules ≤ 4 mm and subtle parenchymal areal opacities is higher with the UTE imaging than standard T1-weighted sequences.
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