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1.
Acad Radiol ; 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32532639

RESUMO

RATIONALE AND OBJECTIVES: Phase resolved functional lung (PREFUL) magnetic resonance imaging (MRI) is a free-breathing 1H-based technique that produces maps of fractional ventilation (FV). This study compared ventilation defect percent (VDP) calculated using PREFUL to hyperpolarized (HP) 129Xe MRI and pulmonary function tests in pediatric cystic fibrosis (CF). MATERIALS AND METHODS: 27 pediatric participants were recruited (mean age 13.0 ± 2.7), including 6 with clinically stable CF, 11 CF patients undergoing a pulmonary exacerbation (PEx), and 10 healthy controls. Spirometry was performed to measure forced expiratory volume in 1 second (FEV1), along with nitrogen multiple breath washout to measure lung clearance index (LCI). VDP was calculated from single central coronal slice PREFUL FV maps and the corresponding HP 129Xe slice. RESULTS: The stable CF group had a normal FEV1 (p = 0.41) and elevated LCI (p = 0.007). The CF PEx group had a decreased FEV1 (p < 0.0001) and elevated LCI (p < 0.0001). PREFUL and HP 129Xe VDP were significantly different between the CF PEx and healthy groups (p < 0.05). In the stable CF group, PREFUL and HP 129Xe VDP were not significantly different from the healthy group (p = 0.18 and 0.08, respectively). There was a correlation between PREFUL and HP 129Xe VDP (R2 = 0.31, p = 0.004), and both parameters were significantly correlated with FEV1 and LCI. CONCLUSION: PREFUL MRI is feasible in pediatric CF, distinguishes patients undergoing pulmonary exacerbations compared to healthy subjects, and correlates with HP 129Xe MRI as well as functional measures of disease severity. PREFUL MRI does not require breath-holds and is straight forward to implement on any MRI scanner.

2.
Rofo ; 2020 May 26.
Artigo em Inglês, Alemão | MEDLINE | ID: mdl-32455442

RESUMO

This information provided by the Thoracic Imaging Section of the German Radiological Society is intended to give physicians recommendations on the use of thoracic imaging procedures in the context of the current COVID-19 pandemic. It represents the consensus of the authors based on the previous scientific knowledge and is intended to provide guidance for unified, structured CT reporting if COVID-19 pneumonia is suspected. The recommendations presented correspond to state of knowledge at the time of print and will be updated according to the results of ongoing and future scientific studies. KEY POINTS:: · COVID-19. · chest imaging. · German Radiological Society. CITATION FORMAT: · Vogel-Claussen J, Ley-Zaporozhan J, Agarwal P et al. Recommendations of the Thoracic Imaging Section of the German Radiological Society for clinical application of chest imaging and structured CT reporting in the COVID-19 pandemic. Fortschr Röntgenstr 2020; DOI: 10.1055/a-1174-8378.

3.
Am J Pathol ; 190(7): 1382-1396, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32275906

RESUMO

Pulmonary hypertension and pulmonary vascular remodeling (PVR) are common in many lung diseases leading to right ventricular dysfunction and death. Differences in PVR result in significant prognostic divergences in both the pulmonary arterial and venous compartments, as in pulmonary arterial hypertension (PAH) and pulmonary veno-occlusive disease (PVOD), respectively. Our goal was to identify compartment-specific molecular hallmarks of PVR, considering the risk of life-threatening pulmonary edema in PVOD, if treated by conventional pulmonary hypertension therapy. Formalin-fixed and paraffin-embedded tissues from fresh explanted human lungs of patients with PVOD (n = 19), PAH (n = 20), idiopathic pulmonary fibrosis (n = 13), and chronic obstructive pulmonary disease (n = 15), were analyzed for inflammation and kinome-related gene regulation. The generated neuronal network differentiated PVOD from PAH samples with a sensitivity of 100% and a specificity of 92% in a randomly chosen validation set, a level far superior to established diagnostic algorithms. Further, various alterations were identified regarding the gene expression of explanted lungs with PVR, compared with controls. Specifically, the dysregulation of microtubule-associated serine/threonine kinase 2 and protein-o-mannose kinase SGK196 in all disease groups suggests a key role in pulmonary vasculopathy for the first time. Our findings promise to help develop novel target-specific interventions and innovative approaches to facilitate clinical diagnostics in an elusive group of diseases.

4.
Magn Reson Med ; 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32227527

RESUMO

PURPOSE: To investigate the diffusion of hyperpolarized 129 Xe in air spaces at short-time scales for determination of lung surface-to-gas-volume ratio in comparison to results from chemical shift saturation recovery, CT, and established clinical measures. METHODS: A pulse sequence for measurement of time-dependent diffusion of 129 Xe in air spaces at short diffusion times was developed. Gas uptake into lung tissue was measured in the same breathhold using chemical shift saturation recovery spectroscopy in the short-time regime. The potential to obtain the surface-to-gas-volume ratio using a first-order and second-order approximation of the short-time expansion of time-dependent diffusion according to Mitra et al11 and its diagnostic relevance were tested in a study with 9 chronic obstructive pulmonary diseases patients. RESULTS: Surface-to-gas-volume ratios obtained from time-dependent diffusion were correlated with results from chemical shift saturation recovery, r = 0.840, P = .005 (first-order fits), and r = 0.923, P < .001 (second-order fits), and from CT results for second-order fits, r = 0.729, P = .026. Group means ± SD were 75.0 ± 15.5 cm-1 (first-order fits) and 122.3 ± 32.8 cm-1 (second-order fits) for time-dependent diffusion, 125.9 ± 43.3 cm-1 for chemical shift saturation recovery, and 159.5 ± 50.9 cm-1 for CT. Surface-to-gas-volume ratios from time-dependent diffusion with first-order fits correlated significantly with carbon monoxide diffusing capacity as percent of prediction, r = 0.724, P = .028. CONCLUSION: Time-dependent diffusion measurements of 129 Xe at short-time scales down to ~1 ms are feasible in chronic obstructive pulmonary patients and provide clinically relevant information on lung microstructure.

5.
J Magn Reson Imaging ; 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32166832

RESUMO

Pulmonary proton MRI techniques offer the unique possibility of assessing lung function and structure without the requirement for hyperpolarization or dedicated hardware, which is mandatory for multinuclear acquisition. Five popular approaches are presented and discussed in this review: 1) oxygen enhanced (OE)-MRI; 2) arterial spin labeling (ASL); 3) Fourier decomposition (FD) MRI and other related methods including self-gated noncontrast-enhanced functional lung (SENCEFUL) MR and phase-resolved functional lung (PREFUL) imaging; 4) dynamic contrast-enhanced (DCE) MRI; and 5) ultrashort TE (UTE) MRI. While DCE MRI is the most established and well-studied perfusion measurement, FD MRI offers a free-breathing test without any contrast agent and is predestined for application in patients with renal failure or with low compliance. Additionally, FD MRI and related methods like PREFUL and SENCEFUL can act as an ionizing radiation-free V/Q scan, since ventilation and perfusion information is acquired simultaneously during one scan. For OE-MRI, different concentrations of oxygen are applied via a facemask to assess the regional change in T1 , which is caused by the paramagnetic property of oxygen. Since this change is governed by a combination of ventilation, diffusion, and perfusion, a compound functional measurement can be achieved with OE-MRI. The known problem of fast T2 * decay of the lung parenchyma leading to a low signal-to-noise ratio is bypassed by the UTE acquisition strategy. Computed tomography (CT)-like images allow the assessment of lung structure with high spatial resolution without ionizing radiation. Despite these different branches of proton MRI, common trends are evident among pulmonary proton MRI: 1) free-breathing acquisition with self-gating; 2) application of UTE to preserve a stronger parenchymal signal; and 3) transition from 2D to 3D acquisition. On that note, there is a visible convergence of the different methods and it is not difficult to imagine that future methods will combine different aspects of the presented methods.

6.
J Magn Reson Imaging ; 2020 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-32096280

RESUMO

BACKGROUND: The translation of phase-resolved functional lung (PREFUL)-MRI to routine practice in monitoring chronic thromboembolic pulmonary hypertension (CTEPH) still requires clinical corresponding imaging biomarkers of pulmonary vascular disease. PURPOSE: To evaluate successful pulmonary endarterectomy (PEA) via PREFUL-MRI with pulmonary pulse wave transit time (pPTT). STUDY TYPE: Retrospective. POPULATION: Thirty CTEPH patients and 12 healthy controls were included. FIELD STRENGTH/SEQUENCE: For PREFUL-MRI a 2D spoiled gradient echo sequence and for DCE-MRI a 3D time-resolved angiography with stochastic trajectories (TWIST) sequence were performed on 1.5T. ASSESSMENT: Eight coronal slices of PREFUL-MRI were obtained on consecutive 13 days before and 14 days after PEA. PREFUL quantitative lung perfusion (PREFULQ ) phases over the whole cardiac cycle were calculated to quantify pPTT, the time the pulmonary pulse wave travels from the central pulmonary arteries to the pulmonary capillaries. Also, perfusion defect percentage based on pPTT (QDPpPTT ), PREFULQ (QDPPREFUL ), and V/Q match were calculated. For DCE-MRI, pulmonary blood flow (PBF) and QDPPBF were computed as reference. For clinical correlation, mean pulmonary arterial pressure (mPAP) and 6-minute walking distance were evaluated preoperatively and after PEA. STATISTICAL TESTS: The Shapiro-Wilk test, paired two-sided Wilcoxon rank sum test, Dice coefficient, and Spearman's correlation coefficient (ρ) were applied. RESULTS: Median pPTT was significantly lower post PEA (139 msec) compared to pre PEA (193 msec), P = 0.0002. Median pPTT correlated significantly with the mPAP post PEA (r = 0.52, P < 0.008). Median pPTT was distributed more homogeneously after PEA: IQR pPTT decreased from 336 to 281 msec (P < 0.004). Median PREFULQ (P < 0.0002), QDPpPTT (P < 0.0478), QDPPREFUL (P < 0.0001) and V/Q match (P < 0.0001) improved significantly after PEA. Percentage change of PREFULQ correlated significantly with percentage change of 6-minute walking distance (ρ = 0.61; P = 0.0031) 5 months post PEA. DATA CONCLUSION: Perioperative perfusion changes in CTEPH can be detected and quantified by PREFUL-MRI. Normalization of pPTT reflects surgical success and improvement of PREFULQ predicts 6-minute walking distance changes. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2.

7.
Magn Reson Med ; 84(3): 1336-1346, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32060989

RESUMO

PURPOSE: To reduce acquisition time and improve image quality and robustness of ventilation assessment in a single breath-hold using 1 H-guided reconstruction of fluorinated gas (19 F) MRI. METHODS: Reconstructions constraining total variation in the image domain, L1 norm in the wavelet domain, and directional total variation between 19 F and 1 H images were compared in order to accelerate 19 F ventilation imaging using retrospectively undersampled data from a healthy volunteer. Using the optimal constrained reconstruction in 8 patients with chronic obstructive pulmonary disease (16-seconds breath-hold), ventilation maps of various acceleration factors (2-fold to 13-fold) were compared with maps of the full data set using the Dice coefficient, difference in volume defect percentage and overlap percentage, as well as hyperpolarized 129 Xe gas MRI. RESULTS: The reconstruction constraining total variation and directional total variation simultaneously performed best in the healthy volunteer (RMS error = 0.07, structural similarity index = 0.77) for a measurement time of 2 seconds. Using the same reconstruction in the patients with chronic obstructive pulmonary disease, the Dice coefficient of defect volumes was 0.86 ± 0.05, the mean difference in volume defect percentage was -1.0 ± 1.7 percentage points, and the overlap percentage was 87% ± 2% for a measurement time of 6 seconds. Between volume defect percentage of 19 F and 129 Xe, a linear correlation (r = 0.75; P = .03) was found, with 19 F volume defect percentage being significantly higher (mean difference = 11%; P = .04). CONCLUSION: 1 H-guided reconstruction of pulmonary 19 F gas MRI enables reduction of acquisition time while maintaining image quality and robustness of functional parameters.

9.
Pediatr Radiol ; 50(5): 734-749, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31996938

RESUMO

Lung MRI makes it possible to replace up to 90% of CT examinations with radiation-free magnetic resonance diagnostics of the lungs without suffering any diagnostic loss. The individual radiation exposure can thus be relevantly reduced. This applies in particular to children who repeatedly require sectional imaging of the lung, e.g., in tumor surveillance or in chronic lung diseases such as cystic fibrosis. In this paper we discuss various factors that favor the establishment of lung MRI in the clinical setting. Among the many sequences proposed for lung imaging, respiration-triggered T2-W turbo spin-echo (TSE) sequences have been established as a good standard for children. Additional sequences are mostly dispensable. The most important pulmonary findings are demonstrated here in the form of a detailed pictorial essay. T1-weighted gradient echo sequences with ultrashort echo time are a new option. These sequences anticipate signal loss in the lung and deliver CT-like images with high spatial resolution. When using self-gated T1-W ultrashort echo time 3-D sequences that acquire iso-voxel geometry in the sub-millimeter range, secondary reconstructions are possible.

10.
J Magn Reson Imaging ; 51(6): 1669-1676, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31729119

RESUMO

BACKGROUND: Development of antiinflammatory drugs for lung diseases demands novel methods for noninvasive assessment of inflammatory processes in the lung. PURPOSE: To investigate the feasibility of hyperpolarized 129 Xe MRI, 1 H T1 time mapping, and dynamic contrast-enhanced (DCE) perfusion MRI for monitoring the response of human lungs to low-dose inhaled lipopolysaccharide (LPS) challenge compared to inflammatory cell counts from induced-sputum analysis. STUDY TYPE: Prospective feasibility study. POPULATION: Ten healthy volunteers underwent MRI before and 6 hours after inhaled LPS challenge with subsequent induced-sputum collection. FIELD STRENGTH/SEQUENCES: 1.5T/hyperpolarized 129 Xe MRI: Interleaved multiecho imaging of dissolved and gas phase, ventilation imaging, dissolved-phase spectroscopy, and chemical shift saturation recovery spectroscopy. 1 H MRI: Inversion recovery fast low-angle shot imaging for T1 mapping, time-resolved angiography with stochastic trajectories for DCE MRI. ASSESSMENT: Dissolved-phase ratios of 129 Xe in red blood cells (RBC), tissue/plasma (TP) and gas phase (GP), ventilation defect percentage, septal wall thickness, surface-to-volume ratio, capillary transit time, lineshape parameters in dissolved-phase spectroscopy, 1 H T1 time, blood volume, flow, and mean transit time were determined and compared to cell counts. STATISTICAL TESTS: Wilcoxon signed-rank test, Pearson correlation. RESULTS: The percentage of neutrophils in sputum was markedly increased after LPS inhalation compared to baseline, P = 0.002. The group median RBC-TP ratio was significantly reduced from 0.40 to 0.31, P = 0.004, and 1 H T1 was significantly elevated from 1157.6 msec to 1187.8 msec after LPS challenge, P = 0.027. DCE MRI exhibited no significant changes in blood volume, P = 0.64, flow, P = 0.17, and mean transit time, P = 0.11. DATA CONCLUSION: Hyperpolarized 129 Xe dissolved-phase MRI and 1 H T1 mapping may provide biomarkers for noninvasive assessment of the response of human lungs to LPS inhalation. By its specificity to the alveolar region, hyperpolarized 129 Xe MRI together with 1 H T1 mapping adds value to sputum analysis. LEVEL OF EVIDENCE: 1 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1669-1676.

11.
J Magn Reson Imaging ; 51(2): 571-579, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31276264

RESUMO

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is associated with high morbidity and mortality. Identification of imaging biomarkers for phenotyping is necessary for future treatment and therapy monitoring. However, translation of visual analytic pipelines into clinics or their use in large-scale studies is significantly slowed by time-consuming postprocessing steps. PURPOSE: To implement an automated tool chain for regional quantification of pulmonary microvascular blood flow in order to reduce analysis time and user variability. STUDY TYPE: Prospective. POPULATION: In all, 90 MRI scans of 63 patients, of which 31 had a COPD with a mean Global Initiative for Chronic Obstructive Lung Disease status of 1.9 ± 0.64 (µ ± σ). FIELD STRENGTH/SEQUENCE: 1.5T dynamic gadolinium-enhanced MRI measurement using 4D dynamic contrast material-enhanced (DCE) time-resolved angiography acquired in a single breath-hold in inspiration. [Correction added on August 20, 2019, after first online publication: The field strength in the preceding sentence was corrected.] ASSESSMENT: We built a 3D convolutional neural network for semantic segmentation using 29 manually segmented perfusion maps. All five lobes of the lung are denoted, including the middle lobe. Evaluation was performed on 61 independent cases from two sites of the Multi-Ethnic Study of Arteriosclerosis (MESA)-COPD study. We publish our implementation of a model-free deconvolution filter according to Sourbron et al for 4D DCE MRI scans as open source. STATISTICAL TEST: Cross-validation 29/61 (# training / # testing), intraclass correlation coefficient (ICC), Spearman ρ, Pearson r, Sørensen-Dice coefficient, and overlap. RESULTS: Segmentations and derived clinical parameters were processed in ~90 seconds per case on a Xeon E5-2637v4 workstation with Tesla P40 GPUs. Clinical parameters and predicted segmentations exhibit high concordance with the ground truth regarding median perfusion for all lobes with an ICC of 0.99 and a Sørensen-Dice coefficient of 93.4 ± 2.8 (µ ± σ). DATA CONCLUSION: We present a robust end-to-end pipeline that allows for the extraction of perfusion-based biomarkers for all lung lobes in 4D DCE MRI scans by combining model-free deconvolution with deep learning. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:571-579.

13.
Magn Reson Med ; 83(3): 1045-1054, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31517406

RESUMO

PURPOSE: To evaluate the influence of intravenously administered gadolinium-based contrast agents on functional ventilation and perfusion parameters derived by phase-resolved functional lung (PREFUL) MRI. METHODS: Fourteen participants underwent functional MRI at 1.5T using a 2D spoiled gradient echo sequence during free breathing. Three data sets of PREFUL images were obtained-the 1st data set was acquired in mean 33:46 min (SD = 6:20 min) prior, the 2nd and 3rd data sets 43 and 91 s (both SD = 1.9 s), respectively, after i.v. application of gadobutrol. Full respiratory and cardiac cycles were reconstructed and functional parameters of regional ventilation (RV), perfusion (Q), and quantified perfusion (QQuant ) together with perfusion-defected percentages (QDP), ventilation-defected percentages (VDP), and ventilation-perfusion match (VQM) were calculated and compared for systematic differences between the acquired data sets. RESULTS: RV- and Q-values presented no significant alteration after gadobutrol administration. Consequently, QDP, VDP, and VQ maps were not significantly different. Sørensen-Dice coefficients of QDP and VDP maps between the different series varied up to ±9%. QQuant was significantly increased after the application of gadobutrol (1st vs. 2nd series, P = 0.0021; 1st vs. 3rd, P = 0.0188), which can be explained by the velocity-dependent signal in the completely blood-filled voxel (ROI of the aorta) after shortening of T1 relaxation time (1st vs. 2nd series, P = 0.0003; 1st vs. 3rd series, P = 0.0008). CONCLUSION: Except for quantified perfusion, all evaluated functional parameters including ventilation- and perfusion-weighted maps derived by PREFUL MRI were independent of gadolinium-based contrast agents, which is important for the design of MRI protocols in future studies.

14.
J Magn Reson Imaging ; 52(1): 103-114, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31872556

RESUMO

BACKGROUND: Perfusion-weighted (Qw) noncontrast-enhanced proton lung MRI is a promising technique for assessment of pulmonary perfusion, but still requires validation. PURPOSE: To improve perfusion-weighted phase-resolved functional lung (PREFUL)-MRI, to validate PREFUL with perfusion single photon emission computed tomography (SPECT) as a gold standard, and to compare PREFUL with dynamic contrast-enhanced (DCE)-MRI as a reference. STUDY TYPE: Retrospective. POPULATION: Twenty patients with chronic obstructive pulmonary disease (COPD), 14 patients with cystic fibrosis (CF), and 21 patients with chronic thromboembolic pulmonary hypertension (CTEPH) were included. FIELD STRENGTH/SEQUENCE: For PREFUL-MRI, a spoiled gradient echo sequence and for DCE-MRI a 3D time-resolved angiography with stochastic trajectories sequence were used at 1.5T. ASSESSMENT: PREFUL-MRI coronal slices were acquired in free-breathing. DCE-MRI was performed in breath-hold with injection of 0.03 mmol/kg bodyweight of gadoteric acid at a rate of 4 cc/s. Perfusion SPECT images were obtained for six CTEPH patients. Images were coregistered. An algorithm to define the appropriate PREFUL perfusion phase was developed using perfusion SPECT data. Perfusion defect percentages (QDP) and Qw-values were calculated for all methods. For PREFUL quantitative perfusion values (PREFULQ ) and for DCE pulmonary blood flow (PBF) was calculated. STATISTICAL TESTS: Obtained parameters were assessed using Pearson correlation and Bland-Altman analysis. RESULTS: Qw-SPECT correlated with Qw-DCE (r = 0.50, P < 0.01) and Qw-PREFUL (r = 0.47, P < 0.01). Spatial overlap of QDP maps showed an agreement ≥67.7% comparing SPECT and DCE, ≥64.1% for SPECT and PREFUL, and ≥60.2% comparing DCE and PREFUL. Significant correlations of Qw-PREFUL and Qw-DCE were found (COPD: r = 0.79, P < 0.01; CF: r = 0.77, P < 0.01; CTEPH: r = 0.73, P < 0.01). PREFULQ /PBF correlations were similar/lower (CF, CTEPH: P > 0.12; COPD: P < 0.01) compared to Qw-PREFUL/DCE correlations. PREFULQ -values were higher/similar compared to PBF-values (COPD, CF: P < 0.01; CTEPH: P = 0.026). DATA CONCLUSION: The automated PREFUL algorithm may allow for noncontrast-enhanced pulmonary perfusion assessment in COPD, CF, and CTEPH patients comparable to DCE-MRI. Level of Evidence 3 Technical Efficacy Stage 2 J. Magn. Reson. Imaging 2020;52:103-114.

15.
Rofo ; 191(11): 993-997, 2019 Nov.
Artigo em Inglês, Alemão | MEDLINE | ID: mdl-31537021

RESUMO

Substantial new data on the early detection of lung cancer with low-dose CT has become available since the last joint statement of the German Radiological Society and the German Respiratory Society was published in 2011. The German S3 guideline on lung cancer was revised in 2018 and now contains a weak recommendation regarding the early detection of lung cancer with low-dose CT in a quality-assured early detection program. These new developments required a change in the position of the involved professional societies. This joint statement describes the main features of a quality-assured program for the early detection of lung cancer with low-dose CT in Germany. KEY POINTS:: · New study data on early detection of lung cancer with low-dose CT and the new German S3 guideline on lung cancer required a new positioning of the involved professional societies.. · The involved professional societies strongly recommend that low-dose CT examinations for early detection of lung cancer should only be performed within a quality-assured program.. · The article describes some fundamentals of such a quality-assured early detection program.. CITATION FORMAT: · Wormanns D, Kauczor H, Antoch G et al. Joint Statement of the German Radiological Society and the German Respiratory Society on a Quality-Assured Early Detection Program for Lung Cancer with Low-Dose CT. Fortschr Röntgenstr 2019; 191: 993 - 997.


Assuntos
Neoplasias Pulmonares/diagnóstico por imagem , Garantia da Qualidade dos Cuidados de Saúde/normas , Doses de Radiação , Tomografia Computadorizada por Raios X/métodos , Diagnóstico Precoce , Alemanha , Humanos , Sociedades Médicas
16.
J Magn Reson Imaging ; 50(6): 1873-1882, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31134705

RESUMO

BACKGROUND: Chronic lung allograft dysfunction (CLAD) is a major cause for the low long-term survival rates after lung transplantation (LTx). Early detection of CLAD may enable providing medical treatment before a nonreversible graft dysfunction has occurred. MRI is advantageous to pulmonary function testing (PFT) in the ability to assess regional function changes, and thus have the potential in detecting very early stages of CLAD before changes in global forced expiratory volume during the first second (FEV1%) occur. PURPOSE: To examine whether early stages of CLAD (diagnosed based on PFT values) could also be detected using MRI-derived parameters of regional flow-volume dynamics. STUDY TYPE: Retrospective. POPULATION: 62 lung transplantation recipients were included in the study, 29 of which had been diagnosed with CLAD at various stages. FIELD STRENGTH/SEQUENCE: MRI datasets were acquired with a 1.5T Siemens scanner using a spoiled gradient echo sequence. ASSESSMENT: MRI datasets were retrospectively preprocessed and analyzed by a blinded radiologist according to the phase resolved functional lung MRI (PREFUL-MRI) approach, resulting in fractional ventilation (FV) maps and regional flow-volume loops (rFVL). FV- and rFVL-based parameters of regional lung ventilation were estimated. STATISTICAL TESTS: Differences between groups were compared by Mann-Whitney U-test with a Bonferroni correction for multiple comparisons (n = 2). RESULTS: rFVL-CC-based parameters discriminated significantly between the presence or absence of CLAD (P < 0.003). DATA CONCLUSION: Using the contrast media-free PREFUL-MRI technique, parameters of ventilation dynamics and its regional heterogeneity were shown to be sensitive for the detection of early CLAD stages. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 3 J. Magn. Reson. Imaging 2019;50:1873-1882.

17.
PLoS One ; 14(3): e0213990, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30883575

RESUMO

OBJECTIVES: To evaluate frequency and severity of complications after CT-guided lung biopsy using the Society of Interventional Radiology (SIR) classification, and to assess risk factors for overall and major complications. MATERIALS AND METHODS: 311 consecutive biopsies with a non-coaxial semi-automated 18 gauge biopsy system were retrospectively evaluated. Complications after biopsy were classified into minor SIR1-2 and major SIR3-6. Studied risk factors for complications were patient-related (age, sex and underlying emphysema), lesion-related (size, location, morphologic characteristic, depth from the pleura and histopathology), and technique-related (patient position during procedure, thoracic wall thickness at needle path, procedure time length and number of procedural CT images, number of pleural passes, fissure penetration and needle-to-blood vessel angle). Data were analyzed using logistic and ordinal regression. RESULTS: Complications were pneumothorax and pulmonary hemorrhage. The complications were minor SIR1-2 in 142 patients (45.6%), and major SIR3-4 in 25 patients (8%). SIR5-6 complications were not present. Emphysema, smaller deeply located lesion, increased puncture time length and number of procedural CT images, multiple pleural passes and fissure puncture were significant risk factors for complication severity in univariate analysis. Emphysema (OR = 8.8, p<0.001), lesion depth from the pleura (OR = 1.9 per cm, p<0.001), and fissure puncture (OR = 9.4, p = 0.01) were the independent factors for major complications in a multiple logistic regression model. No statistical difference of complication rates between the radiologists performing biopsies was observed. CONCLUSIONS: Knowledge about risk factors influencing complication severity is important for planning and performing CT-guided lung biopsies.


Assuntos
Biópsia Guiada por Imagem/efeitos adversos , Pulmão/patologia , Feminino , Hemorragia/etiologia , Humanos , Biópsia Guiada por Imagem/instrumentação , Pulmão/diagnóstico por imagem , Pneumopatias/etiologia , Masculino , Pessoa de Meia-Idade , Pneumotórax/etiologia , Enfisema Pulmonar/diagnóstico por imagem , Enfisema Pulmonar/patologia , Radiografia Intervencionista/efeitos adversos , Estudos Retrospectivos , Fatores de Risco , Tomografia Computadorizada por Raios X
19.
J Thorac Imaging ; 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30801454

RESUMO

There are physiological consequences of overeating that can lead to increased morbidity and mortality. The purpose of this review article is to acquaint the reader with the current state of the art in the non-cardiac-gated, noncontrast chest computed tomographic (NCCT) imaging biomarkers of the metabolic syndrome and their prognostic significance found in the lower neck and chest. NCCT imaging biomarkers associated with metabolic syndrome in the chest include premature coronary artery calcification, acceleration of large vessel arterial and valvular calcifications associated with atherosclerosis, and pulmonary arterial enlargement from pulmonary hypertension associated with sleep apnea. These easily identified imaging biomarkers have prognostic implications for major adverse cardiac events (MACE). These NCCT chest-imaging biomarkers are likely targets for artificial intelligence algorithms to harvest for longitudinal assessment of their individual and multifactorial contributions to chronic disease, MACE, and mortality. Early recognition and treatment of these common disorders may help improve patient outcomes and quality of life while decreasing medical costs.

20.
J Thorac Imaging ; 34(2): 75-85, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30802231

RESUMO

Deep learning is a genre of machine learning that allows computational models to learn representations of data with multiple levels of abstraction using numerous processing layers. A distinctive feature of deep learning, compared with conventional machine learning methods, is that it can generate appropriate models for tasks directly from the raw data, removing the need for human-led feature extraction. Medical images are particularly suited for deep learning applications. Deep learning techniques have already demonstrated high performance in the detection of diabetic retinopathy on fundoscopic images and metastatic breast cancer cells on pathologic images. In radiology, deep learning has the opportunity to provide improved accuracy of image interpretation and diagnosis. Many groups are exploring the possibility of using deep learning-based applications to solve unmet clinical needs. In chest imaging, there has been a large effort to develop and apply computer-aided detection systems for the detection of lung nodules on chest radiographs and chest computed tomography. The essential limitation to computer-aided detection is an inability to learn from new information. To overcome these deficiencies, many groups have turned to deep learning approaches with promising results. In addition to nodule detection, interstitial lung disease recognition, lesion segmentation, diagnosis and patient outcomes have been addressed by deep learning approaches. The purpose of this review article was to cover the current state of the art for deep learning approaches and its limitations, and some of the potential impact on the field of radiology, with specific reference to chest imaging.


Assuntos
Aprendizado Profundo , Pneumopatias/diagnóstico por imagem , Radiografia Torácica/métodos , Tomografia Computadorizada por Raios X/métodos , Humanos , Pulmão/diagnóstico por imagem
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