The aim of this study was to evaluate feasibility and limitations of two MR sequences for imaging of the lung using a semi-quantitative rating scale. Ten healthy volunteers were assessed with a breath-hold T1-weighted gradient-recalled-echo (TR/TE=129/2.2 ms, matrix 173 x 256) and a T2-weighted turbo spin-echo (TSE) sequence with respiratory triggering (TR/TE=3000-5000/120 ms, matrix 270 x 512) in axial 6-mm slices. The T1-weighted GRE protocol included a pre-saturation pulse over the mediastinal structures. Artefacts and resolution of vessel/airway structures in each lung segment were evaluated by two observers (10 volunteers, 180 segments). Cardiac and vessel pulsation artefacts predominated on T1-weighted GRE, respiration artefacts on T2-weighted TSE (lingula and middle lobe). Pre-saturation of the mediastinum reduced pulsation artefacts on T1-weighted GRE. T1-weighted GRE images were improved by bright flow signal of vessels, whereas image quality of T2-weighted TSE was reduced by black-blood effects in central parts of the lung. Delineation of lung periphery and the mediastinum was superior with T2-weighted TSE. Segmental/sub-segmental vessels (up to fourth/fifth order) and bronchi (up to third order) were identified. All 180 lung segments were imaged in diagnostic quality with at least one of the two sequences (T1-weighted GRE not diagnostic in 9 of 180, T2-weighted TSE in 4 of 180). Both sequences were found to be complementary: superior identification of gross lung anatomy with T1-weighted GRE and higher detail resolution in the periphery and the mediastinum with T2--weighted TSE.
"Direct visualisation of the airways with MRI is limited to airways in excess of 3 mm diameter, unless filled with bright materials such as retained mucus in cystic fibrosis patients [65, 66] (Fig. 5). In young healthy subjects, lung MRI depicted airways down to the first subsegmental level; however, in parts of the lung subject to cardiac pulsation, detection rates were significantly lower . As expected from the higher spatial resolution, high resolution CT is still superior to MRI in the depiction of small peripheral airways. "
[Show abstract][Hide abstract] ABSTRACT: Among the modalities for lung imaging, proton magnetic resonance imaging (MRI) has been the latest to be introduced into clinical practice. Its value to replace X-ray and computed tomography (CT) when radiation exposure or iodinated contrast material is contra-indicated is well acknowledged: i.e. for paediatric patients and pregnant women or for scientific use. One of the reasons why MRI of the lung is still rarely used, except in a few centres, is the lack of consistent protocols customised to clinical needs.
This article makes non-vendor-specific protocol suggestions for general use with state-of-the-art MRI scanners, based on the available literature and a consensus discussion within a panel of experts experienced in lung MRI.
Various sequences have been successfully tested within scientific or clinical environments. MRI of the lung with appropriate combinations of these sequences comprises morphological and functional imaging aspects in a single examination. It serves in difficult clinical problems encountered in daily routine, such as assessment of the mediastinum and chest wall, and even might challenge molecular imaging techniques in the near future.
This article helps new users to implement appropriate protocols on their own MRI platforms. Main Messages • MRI of the lung can be readily performed on state-of-the-art 1.5-T MRI scanners. • Protocol suggestions based on the available literature facilitate its use for routine • MRI offers solutions for complicated thoracic masses with atelectasis and chest wall invasion. • MRI is an option for paediatrics and science when CT is contra-indicated.
Insights into Imaging 02/2012; 3(4):355-71. DOI:10.1007/s13244-011-0146-8
"Additional steady-state free precession sequence (SSFP) imaging can be performed with free breathing and is highly sensitive for detection of central pulmonary embolism, and provides information on respiratory mechanics [2, 3]. Respiration-triggered T2-weighted sequences are available for uncooperative patients and those with breath-holding difficulties . The sensitivity of this basic protocol for infiltrates and lung nodules is reported to be similar to CT [5–7]. "
[Show abstract][Hide abstract] ABSTRACT: MRI of the lung is recommended in a number of clinical indications. Having a non-radiation alternative is particularly attractive in children and young subjects, or pregnant women.
Provided there is sufficient expertise, magnetic resonance imaging (MRI) may be considered as the preferential modality in specific clinical conditions such as cystic fibrosis and acute pulmonary embolism, since additional functional information on respiratory mechanics and regional lung perfusion is provided. In other cases, such as tumours and pneumonia in children, lung MRI may be considered an alternative or adjunct to other modalities with at least similar diagnostic value.
In interstitial lung disease, the clinical utility of MRI remains to be proven, but it could provide additional information that will be beneficial in research, or at some stage in clinical practice. Customised protocols for chest imaging combine fast breath-hold acquisitions from a "buffet" of sequences. Having introduced details of imaging protocols in previous articles, the aim of this manuscript is to discuss the advantages and limitations of lung MRI in current clinical practice.
New developments and future perspectives such as motion-compensated imaging with self-navigated sequences or fast Fourier decomposition MRI for non-contrast enhanced ventilation- and perfusion-weighted imaging of the lung are discussed. Main Messages • MRI evolves as a third lung imaging modality, combining morphological and functional information. • It may be considered first choice in cystic fibrosis and pulmonary embolism of young and pregnant patients. • In other cases (tumours, pneumonia in children), it is an alternative or adjunct to X-ray and CT. • In interstitial lung disease, it serves for research, but the clinical value remains to be proven. • New users are advised to make themselves familiar with the particular advantages and limitations.
Insights into Imaging 01/2012; 3(4):373-86. DOI:10.1007/s13244-011-0142-z
"A dark blood preparation pulse may be favorable for particular purposes such as imaging of the mediastinum. As an alternative to breath hold imaging, fast T2-weighted spin-echo sequences with respiratory triggering have produced reasonable results (Leutner and Schild 2001; Biederer et al. 2002a). As discussed above, full anatomic coverage of the chest is highly appreciated to overcome respiratory motion artifacts or overlap-effects between multiple breath hold acquisition. "
[Show abstract][Hide abstract] ABSTRACT: MRI of the lung has been shown to be highly sensitive to infiltrative and solid pathology. It offers particular advantages
beyond the scope of CT such as dynamic studies of respiratory mechanics and first pass perfusion imaging. However, challenges
such as motion artifacts and low signal have delayed the introduction into clinical routine. This chapter discusses the strategies
to overcome these obstacles and suggests a comprehensive protocol for a spectrum of indications. This comprises a basic selection
of non-contrast enhanced sequences and can be extended by contrast enhanced series. Breath hold T1- and T2-weighted imaging
are applied for the detection of small solid lesions and infiltrates. Inversion recovery series visualize enlarged lymph nodes
and skeletal lesions. Steady-state gradient echo series in free breathing contribute to the detection of pulmonary embolism,
cardiac dysfunction and impairment of respiratory mechanics. Tumors, suspicious pleural effusions and inflammatory diseases
warrant additional contrast-enhanced sequences. Perfusion studies contribute to imaging of thromboembolic vascular and obstructive
Note: This list is based on the publications in our database and might not be exhaustive.
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