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  • COMPUTED-TOMOGRAPHY  (11)
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  • 1
    Keywords: measurement ; tumor ; Germany ; LUNG ; CT ; IMAGES ; DISEASE ; NEW-YORK ; TUMORS ; PATIENT ; REDUCTION ; CONTRAST ; MRI ; CYCLE ; SEQUENCE ; NO ; DIFFERENCE ; REGION ; LOCALIZATION ; LENGTH ; COMPUTED-TOMOGRAPHY ; CURVES ; 3-DIMENSIONAL RECONSTRUCTION ; MOTION ; HEALTHY ; ORIENTATION ; LOCATION ; dynamic MRI ; ADULT ; ADULTS ; STRENGTH ; TRUEFISP ; HEALTHY-VOLUNTEERS ; PULMONARY-FUNCTION ; HEART-FAILURE ; EXPIRATION ; LUNG-VOLUMES ; breathing cycle ; diaphragmatic function
    Abstract: The purpose of this study was to assess diaphragmatic length and shortening during the breathing cycle in healthy volunteers and patients with a lung tumor using dynamic MRI (dMRI). In 15 healthy volunteers and 28 patients with a solitary lung tumor, diaphragmatic motion and length were measured during the breathing cycle using a trueFISP sequence (three images per second in the coronal and sagittal plane). Time-distance curves and maximal length reduction (= shortening) of the diaphragm were calculated. The influence of tumor localization on diaphragmatic shortening was examined. In healthy volunteers maximal diaphragmatic shortening was 30% in the coronal and 34% in the sagittal orientation, with no difference between both hemithoraces. Tumors of the upper and middle lung region did not affect diaphragmatic shortening. In contrast, tumors of the lower lung region changed shortening significantly (P〈0.05). In hemithoraces with a tumor in the lower region, shortening was 18% in the coronal and 19% in the sagittal plane. The ratio of diaphragmatic length change from inspiration to expiration changed significantly from healthy subjects (inspiration length &MGT; expiratory length, P〈0.05) to patients with a tumor in the lower lung region (inspiratory length = expiratory length). dMRI is a simple, non-invasive method to evaluate diaphragmatic motion and shortening in volunteers and patients during the breathing cycle. Tumors of the lower lung region have a significant influence on shortening of the diaphragm
    Type of Publication: Journal article published
    PubMed ID: 15127220
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  • 2
    Keywords: CANCER ; COMPUTED-TOMOGRAPHY ; HELICAL CT ; MANAGEMENT ; GUIDELINES ; IMAGE QUALITY ; CHEST CT ; STATEMENT ; SCREENING TRIAL ; LOW-DOSE CT
    Abstract: OBJECTIVES: To evaluate the influence of exposure parameters and raw-data based iterative reconstruction (IR) on the measurement variability of computer-aided nodule volumetry on chest multidetector computed tomography (MDCT). MATERIALS AND METHODS: N=7 porcine lung explants were inflated in a dedicated ex vivo phantom and prepared with n=162 artificial nodules. MDCT was performed eight consecutive times (combinations of 120 and 80 kV with 120, 60, 30 and 12 mAs), and reconstructed with filtered back projection (FBP) and IR. Nodule volume and diameter were measured semi-automatically with dedicated software. The absolute percentage measurement error (APE) was computed in relation to the 120 kV 120 mAs acquisition. Noise was recorded for each nodule in every dataset. RESULTS: Mean nodule volume and diameter were 0.32 +/- 0.15 ml and 12.0 +/- 2.6mm, respectively. Although IR reduced noise by 24.9% on average compared to FBP (p〈0.007), APE with IR was equal to or slightly higher than with FBP. Mean APE for volume increased significantly below a volume computed tomography dose index (CTDI) of 1.0 mGy: for 120 kV 12 mAs APE was 3.8 +/- 6.2% (FBP) vs. 4.0 +/- 5.2% (IR) (p〈0.007); for 80 kV 12 mAs APE was 8.0 +/- 13.0% vs. 9.3 +/- 15.8% (n.s.), respectively. Correlating APE with image noise revealed that at identical noise APE was higher with IR than with FBP (p〈0.05). CONCLUSIONS: Computer-aided volumetry is robust in a wide range of exposure settings, and reproducibility is reduced at a CTDI below 1.0 mGy only, but the error rate remains clinically irrelevant. Noise reduction by IR is not detrimental for measurement error in the setting of semi-automatic nodule volumetry on chest MDCT.
    Type of Publication: Journal article published
    PubMed ID: 23727376
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  • 3
    Keywords: QUANTIFICATION ; COMPUTED-TOMOGRAPHY ; OBSTRUCTIVE PULMONARY-DISEASE ; SMOKERS ; multidetector CT ; SEX-DIFFERENCES ; SHORT-TERM ; COPD ; VOLUME-REDUCTION SURGERY ; AIR-FLOW OBSTRUCTION
    Abstract: Purpose: The change of emphysema distribution with increasing COPD severity is not yet assessed. Especially, involvement of the upper aspect of the lower lobe is unknown. The primary aim was to quantitatively determine regional distribution of emphysema in anatomically (lung lobes) and non-anatomically defined lung regions (upper/lower lung halves as well as core and rind regions) in a cohort covering equally all COPD severity stages using CT. Material and Methods: Basically 100 CT data sets were quantitatively evaluated for regional distribution of emphysema. Emphysema characteristics (emphysema index, mean lung density and 15th percentile of the attenuation values of lung voxels) were compared (t-test) in: upper lobes vs. upper halves, lower lobes vs. lower halves, core vs. rind region. Results: In patients with 〈= GOLD II, a significantly higher emphysema burden was found in the upper lobes as compared to upper halves. In subjects with GOLD III/IV the differences were not significant for all emphysema characteristics. A high difference between lobes and halves in subjects with 〈= GOLD II was found, in contrast to low difference in higher GOLD stages. Conclusions: Lobar segmentation provides improved characterization of cranio-caudal emphysema distribution compared to a non-anatomic approach in subjects up to GOLD stage II.
    Type of Publication: Journal article published
    PubMed ID: 25230093
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  • 4
    Keywords: Germany ; LUNG ; imaging ; SYSTEM ; SYSTEMS ; VOLUME ; SAMPLE ; COMPONENTS ; ACCURACY ; MR ; magnetic resonance ; MAGNETIC-RESONANCE ; magnetic resonance imaging ; DIFFERENCE ; AGE ; COMPONENT ; PARAMETERS ; COMPUTED-TOMOGRAPHY ; BODY ; MR imaging ; dynamic magnetic resonance imaging ; BODIES ; CAPACITY ; OBSTRUCTION ; PULMONARY-FUNCTION TESTS ; development ; DIAPHRAGM ; HEALTHY-SUBJECTS ; CYSTIC-FIBROSIS ; SPIROMETRY ; INTERVAL ; analysis ; function ; LUNG-VOLUME ; female ; Male ; AGREEMENT ; RESONANCE ; body posture ; lung function tests ; magnetic resonance-compatible-spirometry ; nonsmokers ; pulmonary mechanics
    Abstract: The aim of this study was to assess the feasibility and accuracy of a novel magnetic resonance-compatible (MRc)-spirometer. The influence of body posture, magnetic resonance (MR)-setting and image acquisition on lung function was evaluated. Dynamic MR imaging (dMRI) was compared with simultaneously measured lung function. The development of the MRc-spirometer was based on a commercial spirometer and evaluated by flow-generator measurements and forced expiratory manoeuvres in 34 healthy nonsmokers (17 females and 17 males, mean age 32.9 yrs). Mean differences between forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were calculated and a sample paired t-test and Bland-Altman plots were generated. A total of I I subjects underwent different subsequent MRc-spirometric measurements to assess the influence of the components of the MR system on lung function. The mean (95% confidence interval) difference of FEV1 and FVC between the two systems was 0.004 (-0.04-0.04) L and 0.018 (-0.05-0.09) L, respectively. In the subgroup analysis, an influence of the MR-system on FEV1 was found. FEV1 correlated well with the dMRI measurement of the apico-diaphragmatic distance-change after the first second of forced expiration (r=0.72). In conclusion, magnetic resonance-compatible-spirometry is feasible, reliable and safe. The magnetic resonance-setting only has a small influence on simultaneously measured forced expiratory volume in one second. Dynamic magnetic resonance imaging measurements correlate well with simultaneously acquired lung function parameters
    Type of Publication: Journal article published
    PubMed ID: 17715166
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  • 5
    Keywords: PERFUSION ; CT ; COMPUTED-TOMOGRAPHY ; REGIONAL VENTILATION
    Abstract: Purpose: To compare unenhanced lung ventilation-weighted (VW) and perfusion-weighted (QW) imaging based on Fourier decomposition (FD) magnetic resonance (MR) imaging with the clinical reference standard single photon emission computed tomography (SPECT)/computed tomography (CT) in an animal experiment. Materials and Methods: The study was approved by the local animal care committee. Lung ventilation and perfusion was assessed in seven anesthetized pigs by using a 1.5-T MR imager and SPECT/CT. For time-resolved FD MR imaging, sets of lung images were acquired by using an untriggered two-dimensional balanced steady-state free precession sequence (repetition time, 1.9 msec; echo time, 0.8 msec; acquisition time per image, 118 msec; acquisition rate, 3.33 images per second; flip angle, 75 degrees; section thickness, 12 mm; matrix, 128 x 128). Breathing displacement was corrected with nonrigid image registration. Parenchymal signal intensity was analyzed pixelwise with FD to separate periodic changes of proton density induced by respiration and periodic changes of blood flow. Spectral lines representing respiratory and cardiac frequencies were integrated to calculate VW and QW images. Ventilation and perfusion SPECT was performed after inhalation of dispersed technetium 99m ((99m)Tc) and injection of (99m)Tc-labeled macroaggregated albumin. FD MR imaging and SPECT data were independently analyzed by two physicians in consensus. A regional statistical analysis of homogeneity and pathologic signal changes was performed. Results: Images acquired in healthy animals by using FD MR imaging and SPECT showed a homogeneous distribution of VW and QW imaging and pulmonary ventilation and perfusion, respectively. The gravitation-dependent signal distribution of ventilation and perfusion in all animals was similarly observed at FD MR imaging and SPECT. Incidental ventilation and perfusion defects were identically visualized by using both modalities. Conclusion: This animal experiment demonstrated qualitative agreement in the assessment of regional lung ventilation and perfusion between contrast media-free and radiation-free FD MR imaging and conventional SPECT/CT.
    Type of Publication: Journal article published
    PubMed ID: 21586678
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  • 6
    Keywords: DIAGNOSIS ; SYSTEMS ; TIME ; REPRODUCIBILITY ; COMPUTED-TOMOGRAPHY ; THIN-SECTION CT ; magnetic resonance imaging (MRI) ; CHILDREN ; ADULTS ; cystic fibrosis ; Lung disease ; Scoring system
    Abstract: Magnetic resonance imaging (MRI) gains increasing importance in the assessment of cystic fibrosis (CF) lung disease. The aim of this study was to develop a morpho-functional MR-scoring-system and to evaluate its intra- and inter-observer reproducibility and clinical practicability to monitor CF lung disease over a broad severity range from infancy to adulthood. 35 CF patients with broad age range (mean 15.3years; range 0.5-42) were examined by morphological and functional MRI. Lobe based analysis was performed for parameters bronchiectasis/bronchial-wall-thickening, mucus plugging, abscesses/sacculations, consolidations, special findings and perfusion defects. The maximum global score was 72. Two experienced radiologists scored the images at two time points (interval 10weeks). Upper and lower limits of agreement, concordance correlation coefficients (CCC), total deviation index and coverage probability were calculated for global, morphology, function, component and lobar scores. Global scores ranged from 6 to 47. Intra- and inter-reader agreement for global scores were good (CCC: 0.98 (R1), 0.94 (R2), 0.97 (R1/R2)) and were comparable between high and low scores. Our results indicate that the proposed morpho-functional MR-scoring-system is reproducible and applicable for semi-quantitative evaluation of a large spectrum of CF lung disease severity. This scoring-system can be applied for the routine assessment of CF lung disease and maybe as endpoint for clinical trials.
    Type of Publication: Journal article published
    PubMed ID: 21429685
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  • 7
    Keywords: CT ; FLOW ; COMPUTED-TOMOGRAPHY ; PULMONARY-EMBOLISM ; proton MRI ; INITIAL-EXPERIENCE ; DUAL-ENERGY TECHNIQUE
    Abstract: PURPOSE: To assess the reproducibility of Fourier decomposition (FD) based ventilation- and perfusion-weighted lung MRI. METHODS: Sixteen healthy volunteers were examined on a 1.5 T whole-body MR-scanner with 4-6 sets of coronal slices over the chest volume with a non-contrast enhanced steady-state free precession sequence. The identical protocol was repeated after 24h. Reconstructed perfusion- and ventilation-weighted images were obtained through non-rigid registration and FD post-processing of images. Analysis of signal in segmented regions of interest was performed for both native and post-processed data. Two blinded chest radiologists rated image quality of perfusion- and ventilation-weighted images using a 3-point scale. RESULTS: Reproducibility of signal between the two time points was very good with intra-class correlation coefficients of 0.98, 0.94 and 0.86 for native, perfusion- and ventilation-weighted images, respectively. Perfusion- and ventilation-weighted images were of overall good quality with proportions of diagnostic images of 87-95% and 69-75%, respectively. Lung signal decreased from posterior to anterior slices with image quality of ventilation-weighted images in anterior areas rated worse than in posterior or perfusion-weighted images. Inter- and intra-observer agreement of image quality was good for perfusion and ventilation. CONCLUSIONS: The study demonstrates high reproducibility of ventilation- and perfusion-weighted FD lung MRI.
    Type of Publication: Journal article published
    PubMed ID: 23295084
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  • 8
    Keywords: Germany ; LUNG ; chest ; CT ; DIAGNOSIS ; FOLLOW-UP ; imaging ; DISEASE ; EXPOSURE ; RESOLUTION ; radiation ; PATIENT ; IMPACT ; prognosis ; MRI ; MAGNETIC-RESONANCE ; magnetic resonance imaging ; MORPHOLOGY ; COMPUTED-TOMOGRAPHY ; FUNCTION TESTS ; magnetic resonance imaging (MRI) ; CHILDREN ; HRCT ; fibrosis ; ADULTS ; LIFE ; CYSTIC-FIBROSIS ; TESTS ; technique ; function ; cystic fibrosis ; RADIATION EXPOSURE ; lungs ; improvement of ; gold ; mucoviscidosis
    Abstract: Cystic fibrosis (CF) is a multi-systemic disease with major impact on the lungs. Pulmonary manifestation is crucial for the prognosis and life expectancy of patients. Imaging modalities and lung function tests reflect the pulmonary status in these patients. The standard imaging modality for diagnosis and follow-up of pulmonary changes is chest x-ray. The gold standard for the detection of parenchymal lung changes remains high resolution computed tomography (HRCT), but this is not used routinely for CF-patients due to radiation exposure. Magnetic resonance imaging (MRI) used to be of no importance in monitoring cystic fibrosis lung disease, as shown in studies from the 1980s and early 1990s. The continuing improvement of MRI techniques, however, has allowed for an adequate application of this non-radiation method in diagnosing the major pulmonary findings in CF, in addition to the assessment of lung function
    Type of Publication: Journal article published
    PubMed ID: 16437239
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  • 9
    Keywords: COMBINATION ; Germany ; LUNG ; MODEL ; PERFUSION ; EMPHYSEMA ; IMAGES ; imaging ; TOOL ; VOLUME ; DISEASE ; MRI ; CYCLE ; SEQUENCE ; MAGNETIC-RESONANCE ; magnetic resonance imaging ; REGION ; COMPUTED-TOMOGRAPHY ; MOTION ; HEALTHY ; RE ; HEALTHY-VOLUNTEERS ; CHEST-WALL ; PULMONARY-FUNCTION TESTS ; HUMAN DIAPHRAGM SHAPE ; breathing cycle ; HEALTHY-SUBJECTS ; lung motion ; SPIROMETRY ; view sharing ; volumetry ; dynamic 3D MRI ; respiration
    Abstract: Rationale and Objectives: We sought to investigate lung volume and surface measurements during the breathing cycle using dynamic three-dimensional magnetic resonance imaging (3D MRI). Materials and Methods: Breathing cycles of 20 healthy volunteers were examined using a 2D trueFISP sequence (3 images/second) in combination with a model and segmented 3D FLASH sequence (1 image/second) MR images using view sharing. Segmentation was performed semiautomatically using an interactive region growing technique. Vital capacity (VC) was calculated from MRI using the model (2D) and counting the voxels (3D) and was compared with spirometry. Results: VC from spirometry was 4.9 +/- 0.9 L, 4.4 +/- 1.2 L from 2D MRI measurement, and 4.7 +/- 0.9 L for 3D MRI. Using the 3D technique, correlation to spirometry was higher than using the 2D technique (r 〉 0.95 vs. r 〉 0.83). Using the 3D technique, split lung volumes and lung surface could be calculated. There was a significant difference between the left and right lung volume in expiration (P 〈 0.05). Conclusions: Dynamic 3D MRI is a noninvasive tool to evaluate split lung volumes and lung surfaces during the breathing cycle with a high correlation to spirometry
    Type of Publication: Journal article published
    PubMed ID: 15714092
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  • 10
    Keywords: Germany ; LUNG ; chest ; CT ; FOLLOW-UP ; imaging ; INFORMATION ; SYSTEM ; TOOL ; DEATH ; POPULATION ; computed tomography ; RESOLUTION ; PATIENT ; IMPACT ; CONTRAST ; MRI ; MAGNETIC-RESONANCE ; magnetic resonance imaging ; COMPUTED-TOMOGRAPHY ; CHILDREN ; LUNG PERFUSION ; ADULTS ; PHASE ; cystic fibrosis
    Abstract: Cystic fibrosis (CF) is the most frequent inherited disorder leading to premature death in the Caucasian population. As life expectancy is limited by pulmonary complications, repeated imaging [chest X-ray, multislice high-resolution computed tomography (MS-HRCT)] is required in the follow-up. Magnetic resonance imaging (MRI) of the lung parenchyma is a promising new diagnostic tool. Its value for imaging lung changes caused by CF compared with CT is demonstrated. MRI performs well when compared with CT, which serves as the gold standard. Its lack in spatial resolution is obvious, but advantages in contrast and functional assessment compensate for this limitation. Thus, MRI is a reasonable alternative for imaging the CF lung and should be introduced as a radiation-free modality for follow-up studies in CF patients. For further evaluation of the impact of MRI, systematic studies comparing MRI and conventional imaging modalities are necessary. Furthermore, the value of the additional functional MRI (fMRI) information has to be studied, and a scoring system for the morphological and functional aspect of MRI has to be established
    Type of Publication: Journal article published
    PubMed ID: 16941092
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