MR Imaging Of Lung Research Articles

2361: Voxel-wise analysis of DWI lung MR images using deep learning to predict PD-L1 expression

2361: Voxel-wise analysis of DWI lung MR images using deep learning to predict PD-L1 expression

Artificially-generated consolidations and balanced augmentation increase performance of U-net for lung parenchyma segmentation on MR images.

To improve automated lung segmentation on 2D lung MR images using balanced augmentation and artificially-generated consolidations for training of a convolutional neural network (CNN). From 233 healthy volunteers and 100 patients, 1891 coronal MR images were acquired. Of these, 1666 images without consolidations were used to build a binary semantic CNN for lung segmentation and 225 images (187 without consolidations, 38 with consolidations) were used for testing. To increase CNN performance of segmenting lung parenchyma with consolidations, balanced augmentation was performed and artificially-generated consolidations were added to all training images. The proposed CNN (CNNBal/Cons) was compared to two other CNNs: CNNUnbal/NoCons-without balanced augmentation and artificially-generated consolidations and CNNBal/NoCons-with balanced augmentation but without artificially-generated consolidations. Segmentation results were assessed using Sørensen-Dice coefficient (SDC) and Hausdorff distance coefficient. Regarding the 187 MR test images without consolidations, the mean SDC of CNNUnbal/NoCons (92.1 ± 6% (mean ± standard deviation)) was significantly lower compared to CNNBal/NoCons (94.0 ± 5.3%, P = 0.0013) and CNNBal/Cons (94.3 ± 4.1%, P = 0.0001). No significant difference was found between SDC of CNNBal/Cons and CNNBal/NoCons (P = 0.54). For the 38 MR test images with consolidations, SDC of CNNUnbal/NoCons (89.0 ± 7.1%) was not significantly different compared to CNNBal/NoCons (90.2 ± 9.4%, P = 0.53). SDC of CNNBal/Cons (94.3 ± 3.7%) was significantly higher compared to CNNBal/NoCons (P = 0.0146) and CNNUnbal/NoCons (P = 0.001). Expanding training datasets via balanced augmentation and artificially-generated consolidations improved the accuracy of CNNBal/Cons, especially in datasets with parenchymal consolidations. This is an important step towards a robust automated postprocessing of lung MRI datasets in clinical routine.

Performance of spiral UTE-MRI of the lung in post-COVID patients

Patients recovered from COVID-19 may develop long-COVID symptoms in the lung. For this patient population (post-COVID patients), they may benefit from longitudinal, radiation-free lung MRI exams for monitoring lung lesion development and progression. The purpose of this study was to investigate the performance of a spiral ultrashort echo time MRI sequence (Spiral-VIBE-UTE) in a cohort of post-COVID patients in comparison with CT and to compare image quality obtained using different spiral MRI acquisition protocols. Lung MRI was performed in 36 post-COVID patients with different acquisition protocols, including different spiral sampling reordering schemes (line in partition or partition in line) and different breath-hold positions (inspiration or expiration). Three experienced chest radiologists independently scored all the MR images for different pulmonary structures. Lung MR images from spiral acquisition protocol that received the highest image quality scores were also compared against corresponding CT images in 27 patients for evaluating diagnostic image quality and lesion identification. Spiral-VIBE-UTE MRI acquired with the line in partition reordering scheme in an inspiratory breath-holding position achieved the highest image quality scores (score range = 2.17–3.69) compared to others (score range = 1.7–3.29). Compared to corresponding chest CT images, three readers found that 81.5% (22 out of 27), 81.5% (22 out of 27) and 37% (10 out of 27) of the MR images were useful, respectively. Meanwhile, they all agreed that MRI could identify significant lesions in the lungs. The Spiral-VIBE-UTE sequence allows for fast imaging of the lung in a single breath hold. It could be a valuable tool for lung imaging without radiation and could provide great value for managing different lung diseases including assessment of post-COVID lesions.

Application of Highly Flexible Adaptive Image Receive Coil for Lung MR Imaging Using Zero TE Sequence: Comparison with Conventional Anterior Array Coil.

(1) Background: Highly flexible adaptive image receive (AIR) coil has become available for clinical use. The present study aimed to evaluate the performance of AIR anterior array coil in lung MR imaging using a zero echo time (ZTE) sequence compared with conventional anterior array (CAA) coil. (2) Methods: Sixty-six patients who underwent lung MR imaging using both AIR coil (ZTE-AIR) and CAA coil (ZTE-CAA) were enrolled. Image quality of ZTE-AIR and ZTE-CAA was quantified by calculating blur metric value, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of lung parenchyma. Image quality was qualitatively assessed by two independent radiologists. Lesion detection capabilities for lung nodules and emphysema and/or lung cysts were evaluated. Patients’ comfort levels during examinations were assessed. (3) Results: SNR and CNR of lung parenchyma were higher (both p < 0.001) in ZTE-AIR than in ZTE-CAA. Image sharpness was superior in ZTE-AIR (p < 0.001). Subjective image quality assessed by two independent readers was superior (all p < 0.05) in ZTE-AIR. AIR coil was preferred by 64 of 66 patients. ZTE-AIR showed higher (all p < 0.05) sensitivity for sub-centimeter nodules than ZTE-CAA by both readers. ZTE-AIR showed higher (all p < 0.05) sensitivity and accuracy for detecting emphysema and/or cysts than ZTE-CAA by both readers. (4) Conclusions: The use of highly flexible AIR coil in ZTE lung MR imaging can improve image quality and patient comfort. Application of AIR coil in parenchymal imaging has potential for improving delineation of low-density parenchymal lesions and tiny nodules.

An asymmetrical whole-body birdcage RF coil without RF shield for hyperpolarized 129 Xe lung MR imaging at 1.5 T.

This study describes the development and testing of an asymmetrical xenon-129 (129 Xe) birdcage radiofrequency (RF) coil for 129 Xe lung ventilation imaging at 1.5 Tesla, which allows proton (1 H) system body coil transmit-receive functionality. The 129 Xe RF coil is a whole-body asymmetrical elliptical birdcage constructed without an outer RF shield to enable 1 H imaging. field homogeneity and flip angle mapping of the 129 Xe birdcage RF coil and 1 H system body RF coil with the 129 Xe RF coil in situ were evaluated in the MR scanner. The functionality of the 129 Xe birdcage RF coil was demonstrated through hyperpolarized 129 Xe lung ventilation imaging with the birdcage in both transceiver configuration and transmit-only configuration when combined with an 8-channel 129 Xe receive-only RF coil array. The functionality of 1 H system body coil with the 129 Xe RF coil in situ was demonstrated by acquiring coregistered 1 H lung anatomical MR images. The asymmetrical birdcage produced a homogeneous field (±10%) in agreement with electromagnetic simulations. Simulations indicated an optimal detuning configuration with 4 diodes. The obtained g-factor of 1.4 for acceleration factor of R = 2 indicates optimal array configuration. Coregistered 1 H anatomical images from the system body coil along with 129 Xe lung images demonstrated concurrent and compatible arrangement of the RF coils. A large asymmetrical birdcage for homogenous transmission with high sensitivity reception for 129 Xe lung MRI at 1.5 Tesla has been demonstrated. The unshielded asymmetrical birdcage design enables 1 H structural lung MR imaging in the same exam.

The (18)F-FDG positron emission tomography integrated computed tomography associate with intravoxel incoherent motion in prediction of EGFR expression in lung cancer

Objective: To discuss the diagnostic value potential of (18)F-FDG PET/CT and intravoxel incoherent motion (IVIM) in genotype EGFR of lung cancer. Methods: A total of 116 cases proved pathologically pulmonary space occupying lesions (72 males, 44 females; age range was 31-85 years; 37 cases of high differentiation; 53 cases of middle differentiation, 26 cases of low differentiation) were prospectively collected from August 2017 to March 2019 in Henan Provincial People's Hospital. EGFR gene detection was performed in 50 patients (wild type 20 cases, mutant 30 cases). Whole body PET/CT and lung MR-imaging were performed before treatment in all patients. Comparison of PET/CT, IVIM semi-quantitative parameters between positive and negative of EGFR by Student-t test or Mann-Whitney U test. Evaluation diagnostic efficacy of each parameter to EGFR by drawing ROC curves. The optimum diagnostic threshold, specificity, sensitivity, positive predictive value, negative predictive value and the diagnostic accuracy were calculated. The diagnostic accuracy of (18)F-FDG PET/CT combined with IVIM was calculated. Results: The quantitative parameters standard intake(SUV), apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudo-diffusion coefficient (D(*)), perfusion fraction (f) were 8.7±3.5, (1.59±0.26) ×10(-3) mm(2)/s, (1.04±0.12)×10(-3) mm(2)/s, (3.9±3.0)×10(-2) mm(2)/s, 0.43±0.16 and the above parameters of the wild group were 14.3±3.3, (1.34±0.26)×10(-3) mm(2)/s, (0.89±0.12)×10(-3) mm(2)/s, (3.5±2.5)×10(-2) mm(2)/s, 0.40±0.11, respectively. The difference of quantitative parameters SUV (t=4.196, P=0.0001), ADC (t=2.502, P=0.0018), D (t=3.158, P=0.006) between the EGFR mutant group and the wild group was statistically significant. The difference of quantitative parameters D(*) (t=0.361, P=0.721), f (t=0.627, P=0.536) was not statistically significant. ROC curve was drawn and the area under the curves for diagnosis of EGFR mutations by SUV, ADC, D, D(*), f was 0.880, 0.755, 0.820, 0.575, 0.550. The diagnostic accuracy of these parameters above mentioned was 80.0%, 76.7%, 73.3%, 66.7%, 53.3% respectively. The diagnostic accuracy of SUV combined with ADC, D values was 83.3% and 80.0%. Conclusion: PET/CT and IVIM have certain diagnostic value for EGFR typing of lung cancer gene.

Diagnostic performance of zero-TE lung MR imaging in FDG PET/MRI for pulmonary malignancies

ObjectivesThis study aimed to evaluate the diagnostic performance of the lung zero-echo time (ZTE) sequence in FDG PET/MRI for detection and differentiation of lung lesions in oncologic patients in comparison with conventional two-point Dixon-based MR imaging.MethodsIn this single-institution retrospective study approved by the institutional review board, 209 patients with malignancies (97 men and 112 women; age range, 17–89 years; mean age, 66.5 ± 12.9 years) underwent 18F-FDG PET/MRI between August 2017 and August 2018, with diagnostic Dixon and ZTE under respiratory gating acquired simultaneously with PET. Image analysis was performed for PET/Dixon and PET/ZTE fused images by two readers to assess the detectability and differentiation of lung lesions. The reference standard was pathological findings and/or the data from a chest CT. The detection and differentiation abilities were evaluated for all lesions and subgroups divided by lesion size and maximum standardized uptake value (SUVmax).ResultsBased on the reference standard, 227 lung lesions were identified in 113 patients. The detectability of PET/ZTE was significantly better than that of PET/Dixon for overall lesions, lesions with a SUVmax less than 3.0 and lesions smaller than 4 mm (p < 0.01). The diagnostic performance of PET/ZTE was significantly better than that of PET/Dixon for overall lesions and lesions smaller than 4 mm (p < 0.01).ConclusionsZTE can improve diagnostic performance in the detection and differentiation of both FDG-avid and non-FDG-avid lung lesions smaller than 4 mm in size, yielding a promising tool to enhance the utility of FDG PET/MRI in oncology patients with lung lesions.Key Points• The detection rate of PET/ZTE for lesions with a SUVmax of less than 1.0 was significantly better than that of PET/Dixon.• The performance for differentiation of PET/ZTE for lesions that were even smaller than 4 mm in size were significantly better than that of PET/Dixon.• Inter-rater agreement of PET/ZTE for the differentiation of lesions less than 4 mm in size was substantial and better than that of PET/Dixon.

Anthropomorphic phantom for deformable lung and liver CT and MR imaging for radiotherapy

In this study, a functioning and ventilated anthropomorphic phantom was further enhanced for the purpose of CT and MR imaging of the lung and liver. A deformable lung, including respiratory tract was 3D printed. Within the lung’s inner structures is a solid region shaped from a patient’s lung tumour and six nitro-glycerine capsules as reference landmarks. The full internal mesh was coated, and the tumour filled, with polyorganosiloxane based gel. A moulded liver was created with an external casing of silicon filled with polyorganosiloxane gel and flexible plastic internal structures. The liver, fitted to the inferior portion of the right lung, moves along with the lung’s ventilation. In the contralateral side, a cavity is designed to host a dosimeter, whose motion is correlated to the lung pressure. A 4DCT of the phantom was performed along with static and 4D T1 weighted MR images. The CT Hounsfield units (HU) for the flexible 3D printed material were −600–100 HU (lung and liver structures), for the polyorganosiloxane gel 30–120 HU (lung coating and liver filling) and for the silicon 650–800 HU (liver casing). The MR image intensity units were 0–40, 210–280 and 80–130, respectively. The maximum range of motion in the 4D imaging for the superior lung was 1–3.5 mm and 3.5–8 mm in the inferior portion. The liver motion was 5.5–8.0 mm at the tip and 5.7–10.0 mm at the dome. No measurable drift in motion was observed over a 2 h session and motion was reproducible over three different sessions for sin2(t), sin4(t) and a patient-like breathing curve with the interquartile range of amplitudes for all breathing cycles within 0.5 mm. The addition of features within the lung and of a deformable liver will allow the phantom to be used for imaging studies such as validation of 4DMRI and pseudo CT methods.

PH- and thermo-sensitive MTX-loaded magnetic nanocomposites: synthesis, characterization, and in vitro studies on A549 lung cancer cell and MR imaging

In the current study, we proposed a facile method for fabrication of multifunctional pH- and thermo-sensitive magnetic nanocomposites (MNCs) as a theranostic agent for using in targeted drug delivery and magnetic resonance imaging (MRI). To this end, we decorated Fe3O4 magnetic nanoparticles (MNPs) with N,N-dimethylaminoethyl methacrylate (DMAEMA) and N-isopropylacrylamide (NIPAAm), best known for their pH- and thermo-sensitive properties, respectively. We also conjugated mesoporous silica nanoparticles (MSNs) to polymer matrix acting as drug container to enhance the drug encapsulation efficacy. Methotroxate (MTX) as a model drug was successfully loaded in MNCs (M-MNCs) via surface adsorption onto MSNs and electrostatic interaction between drug and carrier. The pH- and temperature-triggered release of MTX was concluded through the evaluation of in vitro release at both physiological and simulated tumor tissue conditions. Based on in vitro cytotoxicity assay results, M-MNCs significantly revealed higher antitumor activity compared to free MTX. In vitro MR susceptibility experiment showed that M-MNCs relatively possessed high transverse relaxivity (r2) of about 0.15 mM−1·ms−1 and a linear relationship between the transverse relaxation rate (R2) and the Fe concentration in the M-MNCs was also demonstrated. Therefore, the designed MNCs can potentially become smart drug carrier, while they also can be promising MRI negative contrast agent.

RF instrumentation for same-breath triple nuclear lung MR imaging of (1)H and hyperpolarized (3)He and (129)Xe at 1.5T.

PurposeThe hyperpolarized gases 3He and 129Xe have distinct properties and provide unique and complementary functional information from the lungs. A triple‐nuclear, same‐breath imaging examination of the lungs with 1H, 3He, and 129Xe can therefore provide exclusive functional information from the gas images. In addition, the 1H images provide complementary co‐registered structural information in the same physiological time frame. The goal of this study was to design an RF system for triple nuclear lung MRI at 1.5T, consisting of a dual‐tuned transceiver coil for 3He and 129Xe, RF switches and a nested 1H receiver array.MethodsA dual‐tuned transmit‐receive dual‐Helmholtz RF coil for 3He and 129Xe was designed and constructed to work in unison with a nested 1H receiver array.ResultsTriple‐nuclear imaging (structural and ventilation) and apparent diffusion coefficient mapping of the human lungs was performed in the same breath‐hold using the integrated RF system. B1 maps and volumetric ventilation imaging using a three‐dimensional, balanced steady‐state free precession pulse sequence performed with both hyperpolarized 3He and 129Xe indicate good stand‐alone performance of the coil for the respective nucleus.ConclusionTriple‐nuclear same‐breath lung imaging with a dual‐tuned coil (3He and 129Xe) and a nested 1H array has been demonstrated with a custom RF system. Magn Reson Med 75:1841–1848, 2016. © © The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

Perfusion Analysis for Lung MR Images Considering Non-Monotonic Response of Gd-Contrast Agent

In order to remain in a monotonic concentration-signal relationship, tracer with low concentration is usually administrated. A new tracer concentration quantification to determine the non-monotonic effect and to enable the correct interpretation of the MR signal intensity, is proposed. It is based on the evaluation of the MR signal intensity in time that might have multiple peaks. A new method for perfusion analysis is also proposed, that is based on the blood flow inside the vessels like the γ variate model and the extravasation as the two compartment model. Samples of processing results of the proposed method applied to patients with confirmed cancer and pulmonary embolus are presented.

Biodegradable Polysilsesquioxane Nanoparticles as Efficient Contrast Agents for Magnetic Resonance Imaging

Polysilsesquioxane (PSQ) nanoparticles are crosslinked homopolymers formed by condensation of functionalized trialkoxysilanes, and provide an interesting platform for developing biologically and biomedically relevant nanomaterials. In this work, the design and synthesis of biodegradable PSQ particles with extremely high payloads of paramagnetic Gd(III) centers is explored, for use as efficient contrast agents for magnetic resonance imaging (MRI). Two new bis(trialkoxysilyl) derivatives of Gd(III) diethylenetriamine pentaacetate (Gd-DTPA) containing disulfide linkages are synthesized and used to form biodegradable Gd-PSQ particles by base-catalyzed condensation reactions in reverse microemulsions. The Gd-PSQ particles, PSQ-1 and PSQ-2, carry 53.8 wt% and 49.3 wt% of Gd-DTPA derivatives, respectively. In addition, the surface carboxy groups on the PSQ-2 particles can be modified with polyethylene glycol (PEG) and the anisamide (AA) ligand to enhance biocompatibility and cell uptake, respectively. The Gd-PSQ particles are readily degradable to release the constituent Gd(III) chelates in the presence of endogenous reducing agents such as cysteine and glutathione. The MR relaxivities of the Gd-PSQ particles are determined using a 3T MR scanner, with r1 values ranging from 5.9 to 17.8 mMs(-1) on a per-Gd basis. Finally, the high sensitivity of the Gd-PSQ particles as T1 -weighted MR contrast agents is demonstrated with in vitro MR imaging of human lung and pancreatic cancer cells. The enhanced efficiency of the anisamide-functionalized PSQ-2 particles as a contrast agent is corroborated by both confocal laser scanning microscopy imaging and ICP-MS analysis of Gd content in vitro.

In vivo MR imaging of pulmonary perfusion and gas exchange in rats via continuous extracorporeal infusion of hyperpolarized 129Xe.

BackgroundHyperpolarized (HP) 129Xe magnetic resonance imaging (MRI) permits high resolution, regional visualization of pulmonary ventilation. Additionally, its reasonably high solubility (>10%) and large chemical shift range (>200 ppm) in tissues allow HP 129Xe to serve as a regional probe of pulmonary perfusion and gas transport, when introduced directly into the vasculature. In earlier work, vascular delivery was accomplished in rats by first dissolving HP 129Xe in a biologically compatible carrier solution, injecting the solution into the vasculature, and then detecting HP 129Xe as it emerged into the alveolar airspaces. Although easily implemented, this approach was constrained by the tolerable injection volume and the duration of the HP 129Xe signal.Methods and Principal FindingsHere, we overcome the volume and temporal constraints imposed by injection, by using hydrophobic, microporous, gas-exchange membranes to directly and continuously infuse 129Xe into the arterial blood of live rats with an extracorporeal (EC) circuit. The resulting gas-phase 129Xe signal is sufficient to generate diffusive gas exchange- and pulmonary perfusion-dependent, 3D MR images with a nominal resolution of 2×2×2 mm3. We also show that the 129Xe signal dynamics during EC infusion are well described by an analytical model that incorporates both mass transport into the blood and longitudinal relaxation.ConclusionsExtracorporeal infusion of HP 129Xe enables rapid, 3D MR imaging of rat lungs and, when combined with ventilation imaging, will permit spatially resolved studies of the ventilation-perfusion ratio in small animals. Moreover, EC infusion should allow 129Xe to be delivered elsewhere in the body and make possible functional and molecular imaging approaches that are currently not feasible using inhaled HP 129Xe.

Signal-to-noise ratio for hyperpolarized 3 He MR imaging of human lungs: A 1.5 T and 3 T comparison

The signal-to-noise ratio in hyperpolarized noble gas MR imaging is expected to be independent of field strength at frequencies typical of clinical systems (e.g., 1.5 T), where body noise dominates over coil noise. Furthermore, at higher fields (e.g., 3 T), the SNR of lung images may decline due to decreases in T(2) originating from increases in susceptibility-induced field gradients at the air-tissue interface. In this work, the SNR of hyperpolarized (3) He lung imaging at two commonly used clinical field strengths (1.5 T and 3 T) were compared in the same volunteers. Thermally polarized and hyperpolarized (3) He phantoms were used to account for differences in MR imaging system and (3) He polarizer performance, respectively, at the two field strengths. After correcting for T(2) values measured at 1.5 T (16 ± 2 ms) and 3 T (7 ± 1 ms), no significant difference in image SNR between the two field strengths was observed, consistent with theory.

Litz wire radiofrequency receive coils for hyperpolarized noble gas MR imaging of rodent lungs at 73.5 mT

AbstractMagnetic resonance imaging with hyperpolarized noble gases, 3He or 129Xe, has become a promising approach for visualizing lung anatomy and function. The polarization of hyperpolarized noble gases does not depend on the magnetic field strength of the imaging system providing an opportunity to image at magnetic field strengths considerably lower than those typically used for clinical purposes (&lt;0.1 T). At such low fields, image noise is dominated by electronic sources, particularly those originating from the radiofrequency coils. An improvement in image signal‐to‐noise ratio (SNR) is possible at low fields by reducing radiofrequency coil noise using Litz wire. In this work, radiofrequency coils of similar geometry were constructed with either conventional copper wire or three different types of Litz wire and compared in phantoms and in vivo in rat lungs using hyperpolarized 3He and 129Xe gases. The coils were tuned at either 0.866 MHz or 2.385 MHz, corresponding to the Larmor frequencies of 129Xe and 3He at 73.5 mT. The effect of wire spacing and number of windings was investigated. A SNR improvement of up to 131% was obtained with the Litz wire when compared with that of conventional copper wire. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 37B: 75–85, 2010

Compressed sensing in hyperpolarized3He Lung MRI

In this work, the application of compressed sensing techniques to the acquisition and reconstruction of hyperpolarized (3)He lung MR images was investigated. The sparsity of (3)He lung images in the wavelet domain was investigated through simulations based on fully sampled Cartesian two-dimensional and three-dimensional (3)He lung ventilation images, and the k-spaces of 2D and 3D images were undersampled randomly and reconstructed by minimizing the L1 norm. The simulation results show that temporal resolution can be readily improved by a factor of 2 for two-dimensional and 4 to 5 for three-dimensional ventilation imaging with (3)He with the levels of signal to noise ratio (SNR) (approximately 19) typically obtained. The feasibility of producing accurate functional apparent diffusion coefficient (ADC) maps from undersampled data acquired with fewer radiofrequency pulses was also demonstrated, with the preservation of quantitative information (mean ADC(cs) approximately mean ADC(full) approximately 0.16 cm(2) sec(-1)). Prospective acquisition of 2-fold undersampled two-dimensional (3)He images with a compressed sensing k-space pattern was then demonstrated in a healthy volunteer, and the results were compared to the equivalent fully sampled images (SNR(cs) = 34, SNR(full) = 19).

Tracheomalacia in Adults with Cystic Fibrosis: Determination of Prevalence and Severity with Dynamic Cine CT

HomeRadiologyVol. 275, No. 3 PreviousNext CommunicationsFree AccessErrataTracheomalacia in Adults with Cystic Fibrosis: Determination of Prevalence and Severity with Dynamic Cine CTShaunagh McDermott, Sinead C. Barry, Eoin E. Judge, Susan Collins, Pim A. de Jong, Harm A. W. M. Tiddens, Edward F. McKone, Charles G. Gallagher, Jonathan D. DoddShaunagh McDermott, Sinead C. Barry, Eoin E. Judge, Susan Collins, Pim A. de Jong, Harm A. W. M. Tiddens, Edward F. McKone, Charles G. Gallagher, Jonathan D. DoddShaunagh McDermottSinead C. BarryEoin E. JudgeSusan CollinsPim A. de JongHarm A. W. M. TiddensEdward F. McKoneCharles G. GallagherJonathan D. DoddPublished Online:May 21 2015https://doi.org/10.1148/radiol.2015154012MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Originally published in:Radiology 2009;252(2):577–586 DOI: 10.1148/radiol.2522081956Erratum in:Radiology 2015;275(3):934 DOI:10.1148/radiol.2015154012In the author list, the third author should be listed as Eoin P. Judge.Article HistoryPublished online: May 21 2015Published in print: June 2015 FiguresReferencesRelatedDetailsCited ByThat antibiotic prophylaxis should be used in children with repaired oesophageal atresia and or trachea-oesophageal fistula – The case in favourPeter J.Merkus2016 | Paediatric Respiratory Reviews, Vol. 18Accompanying This ArticleTracheomalacia in Adults with Cystic Fibrosis: Determination of Prevalence and Severity with Dynamic Cine CTAug 1 2009RadiologyRecommended Articles Allergic Bronchopulmonary Aspergillosis in Cystic Fibrosis: MR Imaging of Airway Mucus Contrasts as a Tool for DiagnosisRadiology2017Volume: 285Issue: 1pp. 261-269Use of Dynamic Chest Radiography to Assess Treatment of Pulmonary Exacerbations in Cystic FibrosisRadiology2022Volume: 303Issue: 3pp. 675-681Three-dimensional Isotropic Functional Imaging of Cystic Fibrosis Using Oxygen-enhanced MRI: Comparison with Hyperpolarized 3He MRIRadiology2018Volume: 290Issue: 1pp. 229-237Self-gated Non–Contrast-enhanced Functional Lung MR Imaging for Quantitative Ventilation Assessment in Patients with Cystic FibrosisRadiology2016Volume: 283Issue: 1pp. 242-251Quantification of Cystic Fibrosis Lung Disease with Radiomics-based CT ScoresRadiology: Cardiothoracic Imaging2020Volume: 2Issue: 6See More RSNA Education Exhibits CF-SCRIbeR Study: Cystic Fibrosis Structured Radiology Report, Standardisation of CT Reporting in Patients with Pulmonary Cystic Fibrosis (CF)Digital Posters2018Imaging in Cystic Fibrosis Follow-up: What is the News?Digital Posters2019Cystic Fibrosis in Adult Patients: A Pictorial Review of Common and Uncommon Abdominal Manifestations Digital Posters2018 RSNA Case Collection Pulmonary manifestations of cystic fibrosisRSNA Case Collection2020Allergic Bronchopulmonary AspergillosisRSNA Case Collection2021Mounier-Kuhn syndromeRSNA Case Collection2020 Vol. 275, No. 3 Metrics Altmetric Score PDF download

Oxygen‐enhanced MR imaging of mice lungs

Inhaled molecular oxygen has been widely used in humans to evaluate pulmonary ventilation using MRI. MR imaging has recently played a greater role in examining the morphologic and physiologic characteristics of mouse models of lung disease where structural changes are highly correlated to abnormalities in respiratory function. The motivation of this work is to develop oxygen-enhanced MR imaging for mice. Conventional human MR techniques cannot be directly applied to mouse imaging due to smaller dimensions and faster cardiac and respiratory physiology. This study examines the development of oxygen-enhanced MR as a noninvasive tool to assess regional ventilation in spontaneously breathing mice. An optimized cardiac-triggered, respiratory-gated fast spin-echo imaging sequence was developed to address demands of attaining adequate signal from the parenchyma, maintaining practical acquisition times, and compensating for rapid physiological motion. On average, a 20% T1-shortening effect was observed in mice breathing 100% oxygen as compared to air. The effect of ventilation was shown as a significant signal intensity increase of 11% to 16% in the mouse parenchyma with 100% oxygen inhalation. This work demonstrates that adequate contrast and resolution can be achieved using oxygen-enhanced MR to visualize ventilation, providing an effective technique to study ventilation defects in mice.

A variable field strength system for hyperpolarized noble gas MR imaging of rodent lungs

AbstractHyperpolarized Noble Gas (HNG), 3He (helium) or 129Xe (xenon), MR imaging has become a promising approach for visualizing lung anatomy and function. It has been theoretically predicted that low field strengths (0.05–0.2 T) may provide optimal signal‐to‐noise ratio (SNR) and spatial resolution for clinical HNG MR imaging. These optimum field strengths correspond to frequencies between 1.62–6.5 MHz and 0.59–2.35 MHz for 3He and 129Xe respectively. The optimum field strength depends on the size and geometry of the sample and radiofrequency (RF) coil as well as the field dependence of the HNG MR properties in the lung (e.g., relaxation times, susceptibility effects). In particular, little is known about the field dependence of the apparent transverse relaxation time, T, which is expected to strongly influence HNG signal. In this paper, a broadband (0.1–100 MHz) variable field strength MR imaging system for rodents is described. A custom‐built resistive magnet was constructed and shimmed to provide the necessary homogeneity for imaging. RF coils and transmit/receive switches for different frequencies were also developed. Preliminary proton (1H) and hyperpolarized 129Xe images of test objects are presented, including a desiccated lung phantom. In vivo 129Xe signals from rat lungs were acquired at 73.5 mT and T was estimated to be approximately 80 ± 8 ms, in good agreement with previously reported values. The MR system developed should be useful for imaging rodent lungs at different field strengths to verify the expected SNR and spatial resolution possible using HNG imaging and to investigate long range diffusion and oxygen‐induced transverse relaxation. © 2008 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 33B: 124–137, 2008

Schnelles In-vivo-19F-MRT-T1-Mapping zur Messung der Konzentration von fluorinierten Gasen in der Lunge

Ziele: Despite the great success of applying hyperpolarized 3He and 129Xe in the field of morphological and functional MR-imaging of lungs both contrast gases still remain mostly research tools. Therefore, the interest in using thermally polarized fluorinated gases, such as SF6, C2F6 and C4F8 in the MRI-investigations of lungs has grown. The short T1 relaxation time of these gases (1–50ms at 1bar) allows for a short measurement time (<10 s) if imaging is performed in a large animal. As the fraction of fluorinated gases is not linearly correlated to the spin density due to T1 weighting other functional MR parameters are necessary for gas concentration quantification. One of such parameters is the T1 relaxation time itself. The aim of this study was to prove the feasibility of the 19F T1 mapping for the estimation of local partial pressure of fluorinated gases in vivo. Methode: For all experiments, the variable flip angle (VFA) technique was used. First, a variety of investigations on phantoms containing mixtures of C4F8 and O2 in different proportions aiming to proof the VFA method for fluorinated gases were done. Next, ex-vivo measurements in rat lungs were performed to test the method efficiency. The rat was ventilated in-vivo with a mixture of 80% C4F8 with 20% of O2 and then, immediately after death, 5ml of C4F8 were injected additionally. Finally, in-vivo experiments in domestic pig (20–25kg) lungs were done using the same mixture. The scan time in all measurements during inspiratory hold was 60–70 s. All experiments were run on a Siemens Magnetom Vision Experimental 1.5T whole body MRI system using a 25cm birdcage coil. Ergebnis: In the ex-vivo T1-maps regions with various T1 can be identified corresponding to variations of C4F8 concentration. The in-vivo measurements results show essentially broad T1- time distribution (and therefore related C4F8 concentration) that obviously reflects a metabolic processes of gas exchange. In this case metabolic changes of the proportions of gas mixtures (C4F8:O2:CO2) in different lung regions could lead to corresponding variations of T1. Schlussfolgerung: In conclusion, the applicability of the VFA method of T1 measurement for the in-vivo MRI-measurement of lungs with heavy fluorinated gases was demonstrated. The sensitivity of the method is sufficient enough to detect 5–10% variations of gas mixture content in-vivo. Combined with diffusion weighted 19F imaging techniques this may open up a number of new options for the study of lung functions and pathology.