Lung T1 Research Articles

Lung T1 MRI assessments in children with mild cystic fibrosis lung disease.

Lung T1 MRI is a potential method to assess cystic fibrosis (CF)lung disease that is safe, quick, and widely available, but there are no data in children with mild CF lung disease. Assess the ability of lung T1 MRI to detect abnormalities in children with mild CF lung disease. We performed T1 MRI, multiple breath washout (MBW),chest computed tomography (CT),and spirometry in a cohort of 45 children with mild CF lung disease (6-11 years of age). Despite mean normal ppFEV1 values, the majority of children with CF in this study exhibited mild lung disease evident in lung clearance index (LCI)measured by MBW, chest CT Brody scores, and percent normal lung perfusion (%NLP)measured by T1 MRI. The %NLP correlated with chest CT Brody scores, as did LCI, but %NLP and LCI did not correlate with each other. Analysis of the Brody subscores showed that %NLP and LCI largely correlated with different Brody subscores. T1 MRI can detect mild CF lung disease in children and correlates with chest CT findings. The %NLPfrom T1 MRI and LCI correlate with different chest CT Brody subscores, suggesting they provide complementary information about CF lung disease.

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

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.

116 Associations between lung T1 magnetic resonance imaging, chest computed tomography, and multiple-breath washout in young children with mild cystic fibrosis lung disease

116 Associations between lung T1 magnetic resonance imaging, chest computed tomography, and multiple-breath washout in young children with mild cystic fibrosis lung disease

Lung magnetic resonance imaging in systemic sclerosis: a new promising approach to evaluate pulmonary involvement and progression.

Interstitial lung disease (ILD) is frequent and highly disabling in systemic sclerosis (SSc). Magnetic resonance imaging (MRI) is not routinely used to evaluate the lung, due to poorer spatial resolution compared to high-resolution computed tomography (HRCT). We aimed to compare lung MRI signal with HRCT and evaluate the role of MRI in predicting ILD progression. Thirty SSc patients underwent lung MRI and HRCT. STIR and T1 mapping sequences were acquired before and after gadolinium injection. Patients were classified as normal (group 1 with normal HRCT and MRI), discordant (group 2 without ILD signs on HRCT but areas of hyperintensity on MRI), and abnormal (group 3 with ILD signs on HRCT and areas of hyperintensity on MRI). Patients were followed up for ILD progression. Mean STIR and T1 values were different between the three groups (p < 0.0001). STIR values correlated with HRCT score (R = 0.79, p < 0.0001), lung ultrasound B-lines (R = 0.73, p < 0.0001), and %DLco (R = - 0.63, p = 0.0001). Nine events were recorded during a follow-up of 25 ± 20months. Continuous STIR values were independently associated with events (HR 1.018; CI 1.005-1.031, p = 0.005). A STIR value >90ms discriminated patients at a higher risk of worsening pulmonary involvement (HR 8.80; CI 1.81-42.74; p < 0.007). Lung MRI can detect SSc-related ILD, with good correlations with other ILD markers. STIR values, independently of HRCT appearance, may predict worsening lung involvement. Lung MRI, although very preliminary, is a promising tool that in a near future could help selecting patients for an early treatment of SSc-related ILD and a more appropriate use of HRCT. Key points • Lung MRI has the potential to differentiate inflammation-predominant versus fibrosis-predominant lesions, but it is not currently used in routine clinical practice to assess SSc-related ILD. • Lung MRI STIR and T1 values are significantly different between patients with and without SSc-related ILD. STIR values, independently of HRCT appearance, are also able to predict worsening lung involvement over time. • These preliminary data suggest that, in a near future, MRI could support the choice for an early treatment of SSc-related ILD, as well as a more appropriate use of HRCT.

Echo Time-Dependence of Observed Lung T1 in Patients With Cystic Fibrosis and Correlation With Clinical Metrics.

Noninvasive monitoring of early abnormalities and therapeutic intervention in cystic fibrosis (CF) lung disease using MRI is important. Lung T1 mapping has shown potential for local functional imaging without contrast material. Recently, it was discovered that observed lung T1 depends on the measurement echo time (TE). To examine TE-dependence of observed T1 in patients with CF and its correlation with clinical metrics. Prospective. In all, 75 pediatric patients with CF (8.6 ± 6.1 years, range 0.1-23 years), with 32 reexamined after 1 year. Patients were examined at 1.5T using an established MRI protocol and a multiecho inversion recovery 2D ultrashort echo time (UTE) sequence for T1 (TE) mapping at five TEs including TE1 = 70 μs. Morphological and perfusion MRI were assessed by a radiologist (M.W.) with 11 years of experience using an established CF-MRI scoring system. T1 (TE) was quantified automatically. Clinical data including spirometry (FEV1pred%) and lung clearance index (LCI) were collected. T1 (TE) was correlated with the CF-MRI score, clinical data, and LCI. T1 (TE) showed a different curvature in CF than in healthy adults: T1 at TE1 was shorter in CF (1157 ms ± 73 ms vs. 1047 ms ± 70 ms, P < 0.001), but longer at TE3 (1214 ms ± 72 ms vs. 1314 ms ± 68 ms, P < 0.001) and later TEs. The correlations of T1 (TE) with patient age (ρTE1-TE5 = -0.55, -0.44, -0.24, -0.30, -0.22), and LCI (ρTE1-TE5 = -0.43, -0.42, -0.33, 0.27, -0.22) were moderate at ultra-short to short TE (P < 0.001) but decreased for longer TE. Moderate but similar correlations at all TE were found with MRI perfusion score (ρTE1-TE5 = -0.43, -0.51, -0.47, -0.46, -0.44) and FEV1pred% (ρTE1-TE5 = +0.44, +0.44, +0.43, +0.40, +0.39) (P < 0.05). TE should be considered when measuring lung T1 , since observed differences between CF and healthy subjects strongly depend on TE. The different variation of correlation coefficients with TE for structural vs. functional metrics implies that TE-dependence holds additional information which may help to discern effects of tissue structural abnormalities and abnormal perfusion. 2 TECHNICAL EFFICACY STAGE: 1 J. MAGN. RESON. IMAGING 2020;52:1645-1654.

Free breathing lung T1 mapping using image registration in patients with idiopathic pulmonary fibrosis.

To assess the use of image registration for correcting respiratory motion in free breathing lung T1 mapping acquisition in patients with idiopathic pulmonary fibrosis (IPF). The method presented used image registration to synthetic images during postprocessing to remove respiratory motion. Synthetic images were generated from a model of the inversion recovery signal of the acquired images that incorporated a periodic lung motion model. Ten healthy volunteers and 19 patients with IPF underwent 2D Look-Locker T1 mapping acquisition at 1.5T during inspiratory breath-hold and free breathing. Eight healthy volunteers and seven patients with IPF underwent T1 mapping acquisition during expiratory breath-hold. Fourteen patients had follow-up scanning at 6 months. Dice similarity coefficient (DSC) was used to evaluate registration efficacy. Image registration increased image DSC (P < .001) in the free breathing inversion recovery images. Lung T1 measured during a free breathing acquisition was lower in patients with IPF when compared with healthy controls (inspiration: P = .238; expiration: P = .261; free breathing: P = .021). Measured lung T1 was higher in expiration breath-hold than inspiration breath-hold in healthy volunteers (P < .001) but not in patients with IPF (P = .645). There were no other significant differences between lung T1 values within subject groups. The registration technique significantly reduced motion in the Look-Locker images acquired during free breathing and may improve the robustness of lung T1 mapping in patients who struggle to hold their breath. Lung T1 measured during a free breathing acquisition was significantly lower in patients with IPF when compared with healthy controls.

Lung T1 mapping magnetic resonance imaging in the assessment of pulmonary disease in children with cystic fibrosis: a pilot study.

Assessment tools for early cystic fibrosis (CF) lung disease are limited. Detecting early pulmonary disease is crucial to increasing life expectancy by starting interventions to slow the progression of the pulmonary disease with the many treatment options available. To compare the utility of lung T1-mapping MRI with ultrashort echo time (UTE) MRI in children with cystic fibrosis in detecting early stage lung disease and monitoring pulmonary exacerbations. We performed a prospective study in 16 children between September 2017 and January 2018. In Phase 1, we compared five CF patients with normal spirometry (mean 11.2years) to five age- and gender-matched healthy volunteers. In Phase 2, we longitudinally evaluated six CF patients (median 11years) in acute pulmonary exacerbation. All children had non-contrast lung T1-mapping and UTE MRI and spirometry testing. We compared the mean normalized T1 value and percentage lung volume without T1 value in CF patients and healthy subjects in Phase 1 and during treatment in Phase 2. We also performed cystic fibrosis MRI scoring. We evaluated differences in continuous variables using standard statistical tests. In Phase 1, mean normalized T1 values of the lung were significantly lower in CF patients in comparison to healthy controls (P=0.02) except in the right lower lobe (P=0.29). The percentage lung volume without T1 value was also significantly higher in CF patients (P=0.006). UTE MRI showed no significant differences between CF patients and healthy volunteers (P=0.11). In Phase 2, excluding one outlier case who developed systemic disease in the course of treatment, the whole-lung T1 value increased (P=0.001) and perfusion scoring improved (P=0.02) following therapy. We observed no other significant changes in the MRI scoring. Lung T1-mapping MRI can detect early regional pulmonary CF disease in children and might be helpful in the assessment of acute pulmonary exacerbations.

Altered relaxation times in MRI indicate bronchopulmonary dysplasia

We developed a MRI protocol using transverse (T2) and longitudinal (T1) mapping sequences to characterise lung structural changes in preterm infants with bronchopulmonary dysplasia (BPD). We prospectively enrolled 61 infants...

Magnetic Resonance Imaging for Quantitative Assessment of Lung Aeration: A Pilot Translational Study.

Background: Computed tomography is the gold standard for lung aeration assessment, but exposure to ionizing radiation limits its application. We assessed the ability of magnetic resonance imaging (MRI) to detect changes in lung aeration in ex vivo isolated swine lung and the potential of translation of the findings to human MRI scans.Methods: We performed MRI scans in 11 isolated non-injured and injured swine lungs, as well as 6 patients both pre- and post-operatively. Images were obtained using a 1.5 T MRI scanner, with T1 – weighted volumetric interpolated breath-hold examination (VIBE) and T2 – weighted half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences. We scanned swine lungs, with reference samples of water and muscle, at different airway pressure levels: 0, 40, 10, 2 cmH2O. We investigated the relations between MRI signal intensity and both lung density and gas content fraction. We analyzed patients’ images according to the findings of the ex vivo model.Results: In the ex vivo samples, the lung T1 – VIBE signal intensity normalized to water or muscle reference signal correlated with lung density (r2 = 0.98). Thresholds for poorly and non-aerated lung tissue, expressed as MRI intensity attenuation factor compared to the deflated lung, were estimated as 0.70 [95% CI: 0.65–0.74] and 0.28 [95% CI: 0.27–0.30], respectively. In patients, dorsal versus ventral regions had a higher MRI signal intensity both pre- and post-operatively (p = 0.031). Comparing post- versus pre-operative scans, lung volume decreased (p = 0.028), while the following increased: MRI signal intensity in ventral (p = 0.043) and dorsal (p < 0.0001) regions, and percentages of non-aerated (p = 0.028) and poorly aerated tissue volumes (p = 0.028).Conclusion: Magnetic resonance imaging signal intensity is a function of lung density, decreasing linearly with increasing gas content. Lung MRI might be useful for estimating lung aeration. Compared to CT, this technique is radiation-free but requires a longer acquisition time and has a lower spatial resolution.

Variable flip angle 3D ultrashort echo time (UTE) T1 mapping of mouse lung: A repeatability assessment.

Lung T1 is a potential translational biomarker of lung disease. The precision and repeatability of variable flip angle (VFA) T1 mapping using modern 3D ultrashort echo time (UTE) imaging of the whole lung needs to be established before it can be used to assess response to disease and therapy. To evaluate the feasibility of regional lung T1 quantification with VFA 3D-UTE and to investigate long- and short-term T1 repeatability in the lungs of naive mice. Prospective preclinical animal study. Eight naive mice and phantoms. 3D free-breathing radial UTE (8 μs) at 4.7T. VFA 3D-UTE T1 calculations were validated against T1 values measured with inversion recovery (IR) in phantoms. Lung T1 and proton density (S0 ) measurements of whole lung and muscle were repeated five times over 1 month in free-breathing naive mice. Two consecutive T1 measurements were performed during one of the imaging sessions. Agreement in T1 between VFA 3D-UTE and IR in phantoms was assessed using Bland-Altman and Pearson 's correlation analysis. The T1 repeatability in mice was evaluated using coefficient of variation (CV), repeated-measures analysis of variance (ANOVA), and paired t-test. Good T1 agreement between the VFA 3D-UTE and IR methods was found in phantoms. T1 in lung and muscle showed a 5% and 3% CV (1255 ± 63 msec and 1432 ± 42 msec, respectively, mean ± SD) with no changes in T1 or S0 over a month. Consecutive measurements resulted in an increase of 2% in both lung T1 and S0 . VFA 3D-UTE shows promise as a reliable T1 mapping method that enables full lung coverage, high signal-to-noise ratio (∼25), and spatial resolution (300 μm) in freely breathing animals. The precision of the VFA 3D-UTE method will enable better design and powering of studies. 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.

Application of spin echoes in the regime of weak dephasing to T1 -mapping of the lung.

This work presents an approach to mapping the entire lung's proton density and T1 within a single breath-hold and analyzes the apparent T1 when exciting with a spin echo generating pulse in comparison to a standard gradient echo acquisition. An inversion-recovery SNAPSHOT-FLASH sequence with a stack-of-stars k-space readout with a golden angle increment was modified to use a spin echo generating radiofrequency-pulse for excitation. Data of five volunteers were acquired on a 3T scanner and image reconstruction was performed by an iterative algorithm adopted from MR-Fingerprinting. The feasibility of acquiring quantitative maps of the entire lung with a resolution of 5 × 5 × 10 mm within 7.5 s is demonstrated. It is shown that the proposed spin echo forming radiofrequency-pulse increases the apparent proton density compared to a rectangular pulse. Further, the apparent T1 is reduced in the spin echo case compared to the gradient echo sequence. The proposed spin echo based method results in T1 maps that are comparable to the ones that were acquired with ultra-short echo time sequences elsewhere. The T1 shortening is believed to originate from increased signal contributions of the extra vascular compartment, which has a short T2∗ and T1 . Magn Reson Med 79:960-967, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Three-dimensional T1 and T2* mapping of human lung parenchyma using interleaved saturation recovery with dual echo ultrashort echo time imaging (ITSR-DUTE).

To develop and assess a new technique for three-dimensional (3D) full lung T1 and T2* mapping using a single free breathing scan during a clinically feasible time. A 3D stack of dual-echo ultrashort echo time (UTE) radial acquisition interleaved with and without a WET (water suppression enhanced through T1 effects) saturation pulse was used to map T1 and T2* simultaneously in a single scan. Correction for modulation due to multiple views per segment was derived. Bloch simulations were performed to study saturation pulse excitation profile on lung tissue. Optimization of the saturation delay time (for T1 mapping) and echo time (for T2* mapping) was performed. Monte Carlo simulation was done to predict accuracy and precision of the sequence with signal-to-noise ratio of in vivo images used in the simulation. A phantom study was carried out using the 3D interleaved saturation recovery with dual echo ultrashort echo time imaging (ITSR-DUTE) sequence and reference standard inversion recovery spin echo sequence (IR-SE) to compare accuracy of the sequence. Nine healthy volunteers were imaged and mean (SD) of T1 and T2* in lung parenchyma at 3T were estimated through manually assisted segmentation. 3D lung coverage with a resolution of 2.5 × 2.5 × 6 mm3 was performed and nominal scan time was recorded for the scans. Repeatability was assessed in three of the volunteers. Regional differences in T1/T2* values were also assessed. The phantom study showed accuracy of T1 values to be within 2.3% of values obtained from IR-SE. Mean T1 value in lung parenchyma was 1002 ± 82 ms while T2* was 0.85 ± 0.1 ms. Scan time was ∼10 min for volunteer scans. Mean coefficient of variation (CV) across slices was 0.057 and 0.09, respectively. Regional variation along the gravitational direction and between right and left lung were not significant (P = 0.25 and P = 0.06, respectively) for T1. T2* showed significant variation (P = 0.03) along the gravitational direction. Repeatability for three volunteers was within 0.7% for T1 and 1.9% for T2*. 3D T1 and T2* maps of the entire lung can be obtained in a single scan of ∼10 min with a resolution of 2.5 × 2.5 × 6 mm3 . 2 J. Magn. Reson. Imaging 2017;45:1097-1104.

T1 Relaxation Time in Lungs of Asymptomatic Smokers.

PurposeInterest in using T1 as a potential MRI biomarker of chronic obstructive pulmonary disease (COPD) has recently increased. Since tobacco smoking is the major risk factor for development of COPD, the aim for this study was to examine whether tobacco smoking, pack-years (PY), influenced T1 of the lung parenchyma in asymptomatic current smokers.Materials and MethodsLung T1 measurements from 35 subjects, 23 never smokers and 12 current smokers were retrospectively analyzed from an institutional review board approved study. All 35 subjects underwent pulmonary function test (PFT) measurements and lung T1, with similar T1 measurement protocols. A backward linear model of T1 as a function of FEV1, FVC, weight, height, age and PY was tested.ResultsA significant correlation between lung T1 and PY was found with a negative slope of -3.2 ms/year (95% confidence interval [CI] [-5.8, -0.6], p = 0.02), when adjusted for age and height. Lung T1 shortens with ageing among all subjects, -4.0 ms/year (95%CI [-6.3, -1.7], p = 0.001), and among the never smokers, -3.7 ms/year (95%CI [-6.0, -1.3], p = 0.003).ConclusionsA correlation between lung T1 and PY when adjusted for both age and height was found, and T1 of the lung shortens with ageing. Accordingly, PY and age can be significant confounding factors when T1 is used as a biomarker in lung MRI studies that must be taken into account to detect underlying patterns of disease.

T1 characteristics of interstitial pulmonary fibrosis on 3T MRI-a predictor of early interstitial change?

Computed tomography (CT) is routinely used for diagnosis and characterisation of idiopathic pulmonary fibrosis (IPF). The technique however has limited sensitivity in detection and monitoring of early fibrotic changes. The aim of this study was to evaluate T1 characteristics in the radiologically diseased lung parenchyma in IPF patient compared to apparently normal parenchyma in both interstitial lung disease (ILD) patients and healthy volunteers and to investigate the feasibility of the technique in prediction of early fibrotic lung changes that may not be visible on CT. Ten patients with IPF underwent high resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) on the same day of attendance. 3T MRI was repeated in seven patients with IPF to test the reproducibility of results. The control group included healthy volunteers (n=10). A modified look-locker inversion-recovery (MOLLI) sequence (124×192 acquisition matrix; 8 mm slice) was performed during a 15-20 s breathhold in a single slice. The position of MR slice was pre-selected where there was CT evidence of normal and fibrotic lung. MOLLI imaging was performed prior to the contrast administration, and at 15, 25, 30 and 35 min post Gadolinium. The imaging data were then processed with a curve-fitting technique to estimate T1 values. T1 values of the apparent fibrotic and normal lung in IPF patients and normal lung were compared. Fibrotic lung had a higher pre-contrast T1 than either morphologically normal lung in ILD patients or control lung (P=0.02) in healthy volunteers (1309±123, 1069±71, and 1011±172 ms, respectively). Morphologically normal lung T1 and control lung T1 were not significantly different pre-contrast, however, at 10 min after administration of Gadolinium, control lung had a significantly shorter T1 than either fibrotic or morphologically normal lung (494±34, 670±63, and 619±41 ms, respectively; P=0.001). T1 for fibrotic lung continued to decrease until 20 min after contrast agent administration (P≤0.0001), whereas morphologically normal lung T1 did not significantly change after 10 min (P>0.3). This indicates delayed uptake of contrast agent in the fibrotic lung compared with morphologically normal lung. T1 mapping of patients with IPF at 3T is feasible and demonstrates a significant difference between fibrotic lung tissue and morphologically normal lung tissue both before Gadolinium administration and at 10 min delayed post-contrast images. The technique is able to evaluate early fibrosis in patients with apparently morphologically normal lung.

Influence of age and sex on the longitudinal relaxation time, T1, of the lung in healthy never-smokers.

As several studies have provided evidence that lung disease affects the T1 of the human lung, our purpose was to investigate the effect of age on the T1-relaxation time in the lungs of healthy never-smokers, including group difference between sexes. The Snapshot FLASH pulse sequence (inversion recovery with multiple gradient echo read-outs) was used to quantify lung T1 in 30 healthy never-smoking volunteers at 1.5 Tesla. Measurements were performed under breathhold of a tidal inspiration. Additionally, subjects underwent clinical MRI and pulmonary function tests. A linear regression model of T1 as a function of age and sex was tested. The slope of lung T1 at tidal end-inspiration as a function of age was statistically different between males and females (P < 0.001). In a linear regression model of T1 as a function of age and sex, females have slope of -4.1 ms/year (95% confidence interval [CI], [-5.2, -3.0]) at P < 0.001, and males -0.064 ms/year (95% CI, [-1.2, 1.1]) at P = 0.9, with a whole model R(2) = 0.83. The observed dependencies of lung T1 on age and sex are here attributed to a previously reported difference in blood T1 between sexes, and a previously reported decrease of pulmonary blood volume with increasing age. This may have implications for the interpretation of lung T1 measurements in both healthy individuals and patients.

COPD Patients Have Short Lung Magnetic Resonance T1 Relaxation Time

Magnetic resonance imaging (MRI) may provide attractive biomarkers for assessment of pulmonary disease in clinical trials as it is free from ionizing radiation, minimally invasive and allows regional information. The aim of this study was to characterize lung MRI T1 relaxation time as a biomarker of chronic obstructive pulmonary disease (COPD); and specifically its relationship to smoking history, computed tomography (CT), and pulmonary function test (PFT) measurements in comparison to healthy age-matched controls. Lung T1 and inter-quartile range (IQR) of T1 maps from 24 COPD subjects and 12 healthy age-matched non-smokers were retrospectively analyzed from an institutional review board approved study. The subjects underwent PFTs and two separate MR imaging sessions at 1.5 tesla to test T1 repeatability. CT scans were performed on the COPD subjects. T1 repeatability (intraclass correlation coefficient) was 0.72 for repeated scans acquired on two visits. The lung T1 was significantly shorter (p < 0.0001) and T1 IQR was significantly larger (p = 0.0002) for the COPD subjects compared to healthy controls. Lung T1 significantly (p = 0.001) correlated with lung density assessed with CT. Strong significant correlations (p < 0.0001) between lung T1 and all PFT measurements were observed. Cigarette exposure did not correlate with lung T1 in COPD subjects. In conclusion, lung MRI T1 mapping shows potential as a repeatable, radiation free, non-invasive imaging technique in the evaluation of COPD.

Echo-time dependence of observed lung T1 in COPD patients: preliminary results

T1-quantification in the lungs has been demonstrated as a functional tool, especially for oxygen-enhanced imaging. Recently, free-breathing UTE-based methods were introduced to improve lung T1-quantification. This revealed a TE-dependency of measured lung T1, which was attributed to compartimentalisation effects more complex than previously assumed. Since this effect, which is seen best using UTE, reflects tissue composition, it may be of value in the diagnosis of diseases which affect the lung parenchyma. The purpose of this work was to examine this effect in COPD patients.

Echo time dependence of observed T1 in the human lung.

This work is intended to demonstrate that T1 measured in the lungs depends on the echo time (TE) used. Measuring lung T1 can be used to gain quantitative morphological and functional information. It is also shown that this dependence is particularly visible when using an ultra-short TE (UTE) sequence with TE well below 1 ms for T1 quantification in lung tissue, rather than techniques with TE on the order of 1-2 ms. The lungs of 12 healthy volunteers (aged 22 to 33 years) were examined at 1.5 Tesla. A segmented inversion recovery Look-Locker multi-echo sequence based on two-dimensional UTE was used for independent T1 quantification at five TEs between TE1 = 70 μs and TE5 = 2.3 ms. The measured T1 was found to increase gradually with TE from 1060 ± 40 ms at TE1 to 1389 ± 53 ms at TE5 (P < 0.001). Measuring T1 at ultra-short echo times reveals a significant dependence of observed T1 on the echo time. Thus, any comparison of T1 values should also consider the TEs used. However, this dependence on TE could also be exploited to gain additional diagnostic information on the tissue compartments in the lung.

Measurement of longitudinal (T1) relaxation in the human lung at 3.0 Tesla with tissue‐based and regional gradient analyses

The purpose of this study is to measure the longitudinal (T1) relaxation time of human lung parenchyma at 3.0 Tesla (T), independent of large vessel signal, and to examine T1 as a function of position in gravitational, isogravitational, and radial planes. Sixteen subjects were imaged. A series of 16-20 turbo field echo images was acquired over a 6-s period after the application of a single nonselective inversion (180 degrees ) pulse. Tissue-based segmentation was used to separate parenchymal tissue from large pulmonary vascular tissue in the resulting images. Time-intensity curves for each tissue type were constructed and spin-lattice relaxation time was determined by line-fitting the time-intensity curves. The lung slice was divided into 10 regions of interest in the gravitational, isogravitational, and radial directions and regional T1 versus position gradient analyses were performed. The T1 relaxation time of human lung parenchyma at 3.0T was determined to be 1374 +/- 226 ms, while the T1 of blood in large pulmonary vessels was 1623 +/- 236 ms. Whole lung T1 was found to be 1397 +/- 214 ms. T1 of lung parenchyma was found to be significantly shorter than the T1 of blood in large pulmonary vessels and whole lung T1. No regional gradient was seen in the gravitational or isogravitational directions, but a significant gradient was seen in the radial direction.

SAGE mRNA expression in advanced-stage lung cancers

Aims: SAGE and HAGE are recently isolated genes, which were thought to be expressed tumour-specifically, and are potentially coding for tumour-specific antigens recognized by T lymphocytes. The expression of these genes may serve as a useful diagnostic marker in detecting malignant disease. We report the correlation of SAGE and HAGE expression with clinicopathological features in patients with lung cancer who had undergone surgery.Methods: Expression of SAGE and HAGE messenger RNA was evaluated by reverse transcription-polymerase chain reaction (RT-PCR) in 102 lung carcinomas and adjacent histological normal lung samples using LightCycler.Results: SAGE/GAPDH mRNA expression was not significantly different between the tumour of lung cancer tissue (3.777±10.802) and normal lung tissue (3.028±3.356, p=0.7283). There was no relationship between SAGE gene expression and age, gender or N-status. SAGE/GAPDH expression was significantly higher in stage III–IV lung cancer (6.180±16.475) than in stage I lung cancer (1.534±2.591, p=0.0393). SAGE/GAPDH expression was also significantly higher in T4 lung cancer (9.183±23.117) than in T2 lung cancer (2.676±5.943, p=0.0362) and T1 lung cancer (2.373±3.433, p=0.0371).Conclusions: Detection for SAGE mRNA expression is possible in lung cancer samples. There was no relationship between HAGE gene expression and clinicopathological factor, such that the usefulness of detection for HAGE mRNA expression is limited for lung cancer.