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  • 11
    Keywords: CARBON, DIFFUSING-CAPACITY, DIFFUSION, DISEASE, DISEASES, EVALUATE, EXCHANGE, fibrosis, function, FU
    Abstract: Purpose: To evaluate an optimized method for oxygen-enhanced MRI of the lung, using simultaneous electrocardiograph (ECG) and navigator triggering. To correlate oxygen-enhanced MRI with lung function tests assessing alveolar-capillary gas exchange. Materials and Methods: A total of 12 healthy volunteers (aged 20-32 years) and 10 patients (aged 37-87 years) with interstitial lung diseases (ILD) underwent oxygen-enhanced MRI and pulmonary functional tests (PFTs) assessing alveolar-capillary gas exchange. The paradigm room-air-oxygen-room-air was acquired with a nonselective inversion-recovery half-Fourier single-shot turbo spin-echo sequence (inversion time = 1200 msec; acquisition time = 134.5 msec; slice thickness = 20 mm; matrix size = 128 X 128), using simultaneous double triggering (navigator plus ECG trigger). Cross-correlation was performed in regions of interest (ROIs) encompassing both lungs. The number of oxygen-activated pixels over the total number of pixels in the ROIs (OAP%) of volunteers and patients was compared. OAP%s were correlated with PFTs. Results: The mean OAP% of patients was significantly lower than that of volunteers (36.7 vs. 81.7, P = 0.001). OAP% correlated with the transfer lung factor for carbon monoxide (Tlco) (r = 0.64; P = 0.002), the transfer coefficient (Kco) (r = 0.75; P = 0.001), the arterial partial pressure (r = 0.77; P 〈 0.001), and the saturation (r = 0.70; P 〈 0.001) of oxygen. Conclusion: Navigator-triggered oxygen-enhanced MRI of the lung may have a potential role in the quantitative assessment of lung function in ILD
    Type of Publication: Journal article published
    PubMed ID: 17968900
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  • 12
    Keywords: THIN-SECTION CT ; INFANTS ; CHILDREN ; asthma ; LUNG-DISEASE ; cystic fibrosis ; SCORING SYSTEMS ; DIMENSIONS ; airway dimensions ; airway disease ; CHEST RADIOGRAPH ; chronic obstructive pulmonary disease ; FLOW LIMITATION ; quantitative computed tomography ; WALL THICKNESS
    Abstract: Purpose: To evaluate the fully automatic quantification of airway dimensions on chest multidetector computed tomography (MDCT) performed in cystic fibrosis (CF) patients. Airflow indices including predicted forced expiratory volume in 1 second (FEV1%) were used to study the impact on regional lung function. Materials and Methods: MDCT data of patients with CF (14 children and 23 adults) and of control patients (11 children and 22 adults) were used to compute total diameter (TD), lumen area (LA), and wall thickness (WT) using dedicated software. Pulmonary function testing including FEV1% was performed in parallel and correlated with MDCT parameters in a generation-based analysis. Results: TD was largely increased in CF patients (third-generation to fourth-generation airways in children, first to ninth in adults; P 〈 0.05). LA remained unchanged, but WT was also larger in CF compared with controls (third generation to sixth generation in children, first to eleventh in adults; P 〈 0.05). In adult CF patients significant negative correlations for TD, LA, and WT with FEV1% were found for intermediate airways (fifth to seventh generation; r = -0.7 to -0.9) but not in pediatric CF patients and controls. Conclusions: Automatic airway analysis succeeded in quantifying specific pathologies such as airway dilatation and wall thickening in CF patients at different ages. Moreover, our results indicate a shift in main airflow resistance to intermediate airways in cases of chronic CF. The objective computational parameters TD, LA, and WT should be considered for assessment and follow-up of CF airway disease
    Type of Publication: Journal article published
    PubMed ID: 23222199
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  • 13
    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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  • 14
    Keywords: CT ; MICE ; MRI ; INFANTS ; YOUNG-CHILDREN ; RESOLUTION COMPUTED-TOMOGRAPHY ; CHEST RADIOGRAPH ; AIRWAY INFLAMMATION ; INHALED HYPERTONIC SALINE ; CLEARANCE INDEX
    Abstract: Rationale: Studies demonstrating early structural lung damage in infants and preschool children with cystic fibrosis (CF) suggest that noninvasive monitoring will be important to identify patients who may benefit from early therapeutic intervention. Previous studies demonstrated that magnetic resonance imaging (MRI) detects structural and functional abnormalities in lungs from older patients with CF without radiation exposure. Objectives: To evaluate the potential of MRI to detect abnormal lung structure and perfusion in infants and preschool children with CF, and to monitor the response to therapy for pulmonary exacerbation. Methods: MRI studies were performed in 50 children with CF (age, 3.1 +/- 2.1 yr; range, 0-6 yr) in stable clinical condition (n = 40) or pulmonary exacerbation before and after antibiotic treatment (n = 10), and in 26 non-CF control subjects (age, 2.9 +/- 1.9 yr). T1-and T2-weighted sequences before and after intravenous contrast and first-pass perfusion imaging were acquired, and assessed on the basis of a dedicated morphofunctional score. Measurements and Main Results: MRI demonstrated bronchial wall thickening/bronchiectasis, mucus plugging, and perfusion deficits from the first year of life in most stable patients with CF (global score, 10.0 +/- 4.0), but not in non-CF control subjects (score, 0.0 +/- 0.0; P, 0.001). In patients with exacerbations, the global MRI score was increased to 18.0 +/- 2.0 (P, 0.001), and was significantly reduced to 12.0 +/- 3.0 (P, 0.05) after antibiotic therapy. Conclusions: MRI detected abnormalities in lung structure and perfusion, and response to therapy for exacerbations in infants and preschool children with CF. These results support the development of MRI for noninvasive monitoring and as an end point in interventional trials for early CF lung disease. Clinical trial registered with www.clinicaltrials.gov (NCT00760071).
    Type of Publication: Journal article published
    PubMed ID: 24564281
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  • 15
    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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  • 16
    Keywords: CANCER ; DIAGNOSIS ; PERFORMANCE ; REPRODUCIBILITY ; HELICAL CT ; IMAGE QUALITY ; volumetry ; CHEST CT ; RADIOLOGISTS DETECTION ; CAD SOFTWARE
    Abstract: OBJECTIVES: To evaluate the influence of exposure parameters and raw-data based iterative reconstruction (IR) on the performance of computer-aided detection (CAD) of pulmonary nodules on chest multidetector computed tomography (MDCT). MATERIAL AND METHODS: Seven porcine lung explants were inflated in a dedicated ex vivo phantom shell and prepared with n=162 artificial nodules of a clinically relevant volume and maximum diameter (46-1063mul, and 6.2-21.5mm). n=118 nodules were solid and n=44 part-solid. MDCT was performed with different combinations of 120 and 80kV with 120, 60, 30 and 12mA*s, and reconstructed with both filtered back projection (FBP) and IR. Subsequently, 16 datasets per lung were subjected to dedicated CAD software. The rate of true positive, false negative and false positive CAD marks was measured for each reconstruction. RESULTS: The rate of true positive findings ranged between 88.9-91.4% for FBP and 88.3-90.1% for IR (n.s.) with most exposure settings, but was significantly lower with the combination of 80kV and 12mA*s (80.9% and 81.5%, respectively, p〈0.05). False positive findings ranged between 2.3 - 8.1 annotations per lung. For nodule volumes 〈200mul the rate of true positives was significantly lower than for 〉300mul (p〈0.05). Similarly, it was significantly lower for diameters 〈12mm compared to 〉/=12mm (p〈0.05). The rate of true positives for solid and part-solid nodules was similar. CONCLUSIONS: Nodule CAD on chest MDCT is robust over a wide range of exposure settings. Noise reduction by IR is not detrimental for CAD, and may be used to improve image quality in the setting of low-dose MDCT for lung cancer screening.
    Type of Publication: Journal article published
    PubMed ID: 25740701
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  • 17
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    German Medical Science GMS Publishing House; Düsseldorf
    In:  Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018); 20181023-20181026; Berlin; DOCST32-939 /20181106/
    Publication Date: 2018-11-07
    Keywords: Vorderes Kreuzband ; VKB Rekonstruktion ; Sehnentransplantat ; tibiale Fixierung ; Interferenzschraube ; Biomechanik ; ddc: 610
    Language: German
    Type: conferenceObject
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  • 18
    Publication Date: 2018-10-13
    Keywords: ddc: 610
    Language: German
    Type: conferenceObject
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  • 19
    Keywords: BLOOD ; Germany ; LUNG ; QUANTIFICATION ; TIME ; BLOOD-FLOW ; blood flow ; FLOW ; MRI ; PATTERNS ; PARAMETERS ; HYPERTENSION ; BLOOD-FLOW MEASUREMENTS ; BREATH-HOLD ; ENCODED CINE MRI ; HEMODYNAMICS ; RE ; HEALTHY-VOLUNTEERS ; phase-contrast MRI ; pulmonary circulation ; systemic circulation ; VENTRICULAR STROKE VOLUME
    Abstract: OBJECTIVE. The purpose of this study was to use phase-contrast MRI to evaluate the influence of various breathing maneuvers on the hemodynamics of the pulmonary and systemic arterial circulation. SUBJECTS AND METHODS. Twenty-five volunteers were examined with phase-contrast MRI. Flow measurements were acquired in the aorta, pulmonary trunk, and left and right pulmonary arteries during deep, large-volume inspiratory breath-hold, expiratory breath-hold, and smooth respiration (no breath-hold). Parameters assessed were peak velocity, blood flow, velocity gradient, and acceleration time. RESULTS. Pulmonary blood flow and peak velocity were significantly reduced during inspiratory breath-hold and expiratory breath-hold compared with no breath-hold (p 〈 0.01). Pulmonary velocity gradient in inspiratory breath-hold was significantly (p:! 0.01) lower than in expiratory breath-hold and no breath-hold. There was no difference in velocity gradient between expiratory breath-hold and no breath-hold. Peak velocity in the aorta was lowest with no breath-hold. Velocity gradient was highest in expiratory breath-hold, and no breath-hold had the smallest SD. Acceleration time in the pulmonary trunk showed no difference between inspiratory breath-hold, expiratory breath-hold, and no breath-hold. Blood flow distribution to the left (45-47%) and to the right (53-55%) lung was not influenced by breathing maneuver. CONCLUSION. Measurements during smooth respiration showed the smallest SD. Therefore, no-breath-hold measurements should be considered for assessment of hemodynamics in clinical practice
    Type of Publication: Journal article published
    PubMed ID: 16861549
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  • 20
    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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