Bronchial artery dilatation (BAD) is associated with haemoptysis in advanced cystic fibrosis (CF) lung disease. Our aim was to evaluate BAD onset and its association with disease severity by magnetic ...resonance imaging (MRI).
188 CF patients (mean±sd age 13.8±10.6 years, range 1.1-55.2 years) underwent annual chest MRI (median three exams, range one to six exams), contributing a total of 485 MRI exams including perfusion MRI. Presence of BAD was evaluated by two radiologists in consensus. Disease severity was assessed using the validated MRI scoring system and spirometry (forced expiratory volume in 1 s (FEV
) % pred).
MRI demonstrated BAD in 71 (37.8%) CF patients consistently from the first available exam and a further 10 (5.3%) patients first developed BAD during surveillance. Mean MRI global score in patients with BAD was 24.5±8.3 compared with 11.8±7.0 in patients without BAD (p
0.001) and FEV
% pred was lower in patients with BAD compared with patients without BAD (60.8%
82.0%; p<0.001). BAD was more prevalent in patients with chronic
infection
in patients without infection (63.6%
28.0%; p<0.001). In the 10 patients who newly developed BAD, the MRI global score increased from 15.1±7.8 before to 22.0±5.4 at first detection of BAD (p
0.05). Youden indices for the presence of BAD were 0.57 for age (cut-off 11.2 years), 0.65 for FEV
% pred (cut-off 74.2%) and 0.62 for MRI global score (cut-off 15.5) (p
0.001).
MRI detects BAD in patients with CF without radiation exposure. Onset of BAD is associated with increased MRI scores, worse lung function and chronic
infection, and may serve as a marker of disease severity.
Due to hypoxic vasoconstriction, perfusion is interesting in the lungs. Magnetic Resonance Imaging (MRI) perfusion imaging based on Dynamic Contrast Enhancement (DCE) has been demonstrated in ...patients with Chronic Obstructive Pulmonary Diseases (COPD) using visual scores, and quantification methods were recently developed further. Inter-patient correlations of echo time-dependent observed T
T
(TE) have been shown with perfusion scores, pulmonary function testing, and quantitative computed tomography. Here, we examined T
(TE) quantification and quantitative perfusion MRI together and investigated both inter-patient and local correlations between T
(TE) and quantitative perfusion.
22 patients (age 68.0 ± 6.2) with COPD were examined using morphological MRI, inversion recovery multi-echo 2D ultra-short TE (UTE) in 1-2 slices for T
(TE) mapping, and 4D Time-resolved angiography With Stochastic Trajectories (TWIST) for DCE. T
(TE) maps were calculated from 2D UTE at five TEs from 70 to 2,300 μs. Pulmonary Blood Flow (PBF) and perfusion defect (QDP) maps were produced from DCE measurements. Lungs were automatically segmented on UTE images and morphological MRI and these segmentations registered to DCE images. DCE images were separately registered to UTE in corresponding slices and divided into corresponding subdivisions. Spearman's correlation coefficients were calculated for inter-patient correlations using the entire segmented slices and for local correlations separately using registered images and subdivisions for each TE. Median T
(TE) in normal and defect areas according to QDP maps were compared.
Inter-patient correlations were strongest on average at TE
= 500 μs, reaching up to |ρ| = 0.64 for T
with PBF and |ρ| = 0.76 with QDP. Generally, local correlations of T
with PBF were weaker at TE
than at TE
or TE
and with maximum values of |ρ| = 0.66 (from registration) and |ρ| = 0.69 (from subdivision). In 18 patients, T
was shorter in defect areas than in normal areas, with the relative difference smallest at TE
.
The inter-patient correlations of T
with PBF and QDP found show similar strength and TE-dependence as those previously reported for visual perfusion scores and quantitative computed tomography. The local correlations and median T
suggest that not only base T
but also the TE-dependence of observed T
in normal areas is closer to that found previously in healthy volunteers than in defect areas.
Background
Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) allows the assessment of pulmonary perfusion, which may play a key role in the development of muco-obstructive lung disease. ...One problem with quantifying pulmonary perfusion is the high variability of metrics. Quantifying the extent of abnormalities using unsupervised clustering algorithms in residue function maps leads to intrinsic normalization and could reduce variability.
Purpose
We investigated the reproducibility of perfusion defects in percent (QDP) in clinically stable patients with cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD).
Methods
15 CF (29.3 ± 9.3y, FEV1%predicted = 66.6 ± 15.8%) and 20 COPD (66.5 ± 8.9y, FEV1%predicted = 42.0 ± 13.3%) patients underwent DCE-MRI twice 1 month apart. QDP, pulmonary blood flow (PBF), and pulmonary blood volume (PBV) were computed from residue function maps using an in-house quantification pipeline. A previously validated MRI perfusion score was visually assessed by an expert reader.
Results
Overall, mean QDP, PBF, and PBV did not change within 1 month, except for QDP in COPD (
p
< 0.05). We observed smaller limits of agreement (± 1.96
SD
) related to the median for QDP (CF: ± 38%, COPD: ± 37%) compared to PBF (CF: ± 89%, COPD: ± 55%) and PBV (CF: ± 55%, COPD: ± 51%). QDP correlated moderately with the MRI perfusion score in CF (
r
= 0.46,
p
< 0.05) and COPD (
r
= 0.66,
p
< 0.001). PBF and PBV correlated poorly with the MRI perfusion score in CF (
r
=−0.29,
p
= 0.132 and
r
=−0.35,
p
= 0.067, respectively) and moderately in COPD (
r
=−0.57 and
r
=−0.57,
p
< 0.001, respectively).
Conclusion
In patients with muco-obstructive lung diseases, QDP was more robust and showed a higher correlation with the MRI perfusion score compared to the traditionally used perfusion metrics PBF and PBV.
PURPOSETo apply multi-shot high-resolution multi inversion spin and gradient echo (MI-SAGE) acquisition for simultaneous liver T1, T2 and T2* mapping.METHODSInversion prepared spin- and gradient-echo ...EPI was developed with ascending slice order across measurements for efficient acquisition with T1, T2, and T2⁎ weighting. Multi-shot EPI was also implemented to minimize distortion and blurring while enabling high in-plane resolution. A dictionary-matching approach was used to fit the images to quantitative parameter maps, which were compared to T1 measured by modified Look-Locker (MOLLI), T1 measured by variable flip angle (VFA), T2 measured by multiple echo time-based Half Fourier Single-shot Turbo spin-Echo (HASTE), T2 measured by radial turbo-spin-echo (rTSE) and T2⁎ measured by multiple gradient echo (MGRE) sequences.RESULTSThe multi-shot variant of the sequence achieved higher in-plane resolution of 1.7 × 1.7 mm2 with good image quality in 28 s. Derived quantitative maps showed comparable values to conventional mapping methods. As measured in phantom and in vivo, MOLLI, MESE and MGRE give closest values to MISAGE. VFA, HASTE and rTSE show obvious overestimation.CONCLUSIONSThe proposed multi-shot inversion prepared spin- and gradient-echo EPI sequence allows for high-resolution quantitative T1, T2 and T2 liver tissue characterization in a single breath-hold scan.
To apply velocity selective arterial spin labeling (VSASL) combined with a navigator-based (NAV) prospective motion compensation method for a free–breathing liver perfusion measurement without ...contrast agent.
Sinc-modulated Velocity Selective Inversion (sinc-VSI) pulses were applied as labeling and control pulses. In order to account for respiratory motion, a navigator was employed in the form of a single gradient-echo projection readout, located at the diaphragm along the inferior-superior direction. Prior to each transverse imaging slice of the spin-echo EPI based readouts, navigator and fat suppression were incorporated. Motion data was obtained from the navigator and transmitted back to the sequence, allowing real-time adjustments to slice positioning. The sinc-VSI without velocity-selective gradients during the control condition but with velocity-selective gradients along all three directions during labeling was chosen for the VSASL. The VSASL was compared with pseudo-continuous ASL (pCASL) methods, which selectively tagged the moving spins using a tagging plane placed at the portal vein and hepatic artery.
The motion caused by respiratory activity was effectively computed using the navigator signal. The coefficients of variation (CoV) of average liver voxel in NAV were significantly decreased when compared to breath-hold (BH), with an average reduction of 29.4 ± 18.44% for control images, and 29.89 ± 20.83% for label images (p < 0.001). The resulting maps of normalized ASL signal (normalized to M0) showed significantly higher perfusion weightings in the NAV-compensated VSASL, when compared to the NAV-compensated pCASL techniques.
This study demonstrates the feasibility of using a navigator-based prospective motion compensation technique in conjunction with VSASL for the measurement of liver perfusion without the use of contrast agents while allowing for free-breathing.
Background
This work is intended to demonstrate that
T
1
measured in the lungs depends on the echo time (
TE
) used. Measuring lung
T
1
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
T
1
quantification in lung tissue, rather than techniques with
TE
on the order of 1–2 ms.
Methods
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
T
1
quantification at five
TE
s between
TE
1
= 70 μs and
TE
5
= 2.3 ms.
Results
The measured
T
1
was found to increase gradually with
TE
from 1060 ± 40 ms at
TE
1
to 1389 ± 53 ms at
TE
5
(
P
< 0.001).
Conclusion
Measuring
T
1
at ultra‐short echo times reveals a significant dependence of observed
T
1
on the echo time. Thus, any comparison of
T
1
values should also consider the
TE
s used. However, this dependence on
TE
could also be exploited to gain additional diagnostic information on the tissue compartments in the lung. J. Magn. Reson. Imaging 2015;42:610–616.
Noninvasive monitoring of early abnormalities and therapeutic intervention in cystic fibrosis (CF) lung disease using MRI is important. Lung T
mapping has shown potential for local functional imaging ...without contrast material. Recently, it was discovered that observed lung T
depends on the measurement echo time (TE).
To examine TE-dependence of observed T
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 T
(TE) mapping at five TEs including TE
= 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. T
(TE) was quantified automatically. Clinical data including spirometry (FEV1pred%) and lung clearance index (LCI) were collected.
T
(TE) was correlated with the CF-MRI score, clinical data, and LCI.
T
(TE) showed a different curvature in CF than in healthy adults: T
at TE
was shorter in CF (1157 ms ± 73 ms vs. 1047 ms ± 70 ms, P < 0.001), but longer at TE
(1214 ms ± 72 ms vs. 1314 ms ± 68 ms, P < 0.001) and later TEs. The correlations of T
(TE) with patient age (ρ
= -0.55, -0.44, -0.24, -0.30, -0.22), and LCI (ρ
= -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 (ρ
= -0.43, -0.51, -0.47, -0.46, -0.44) and FEV1pred% (ρ
= +0.44, +0.44, +0.43, +0.40, +0.39) (P < 0.05).
TE should be considered when measuring lung T
, 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.
•The chest MRI global score showed a long-term stability in patients under standard therapy without elexacaftor/tezacaftor/ivacaftor.•The chest MRI global score improved in patients under ...Elexacaftor/Tezacaftor/Ivacaftor, mainly due to reduction of bronchiectasis/wall thickening and mucus plugging.•The improved chest MRI global score correlated with proportional improvements in FEV1%.•The chronic rhinosinusitis MRI sum score improved under elexacaftor/tezacaftor/ivacaftor therapy through a reduction of mucopyoceles.
Therapy with Elexacaftor/Tezacaftor/Ivacaftor (ETI) was recently approved for adult cystic fibrosis (CF) patients with at least one F508del mutation. However, its effects on structural and functional lung abnormalities and chronic rhinosinusitis have not been studied by imaging.
19 adults with CF (mean age 31±9y, range 19–55y) underwent standardized chest magnetic resonance imaging (MRI), and nine also same-session sinonasal MRI, before (MRI1) and after (MRI2) at least one month (mean duration 5 ± 3mon) on ETI. 24 control CF patients (30±7y, range 20–44y) without ETI underwent longitudinal chest MRI, and eleven also sinonasal MRI, twice (mean interval 40±15mon). MRI was assessed using the validated chest MRI score and chronic rhinosinusitis (CRS)-MRI score. Forced expiratory volume in 1 s percent predicted (FEV1%) was measured in all patients.
In controls, the chest MRI global score and CRS-MRI sum score were stable from MRI1 to MRI2. In patients under ETI, the chest MRI global score improved (-11.4 ± 4.6, P<0.001), mainly due to reduction of bronchiectasis/wall thickening and mucus plugging subscores (-3.3 ± 2.2 and -5.2 ± 1.5, P<0.001, respectively). The improvement in chest MRI score correlated well with improved FEV1% (r=-0.703, P<0.001). The CRS-MRI sum score also improved in patients under ETI (-6.9 ± 3.0, P<0.001), mainly due to a reduction of mucopyoceles in the maxillary and ethmoid sinus (-50% and -39%, P<0.05, respectively).
MRI detects improvements of chest MRI and CRS-MRI scores in adult CF patients who first received ETI, demonstrating reversibility of structural lung and paranasal sinus abnormalities in patients with established disease.
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