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    Keywords: evaluation ; Germany ; LUNG ; chest ; CT ; FOLLOW-UP ; follow-up studies ; IMAGES ; SUPPORT ; VENTILATION ; VOLUME ; RESOLUTION ; PATIENT ; MRI ; helium ; HEALTHY ; HYPERPOLARIZED HE-3 ; motion correction ; MR imaging ; PULMONARY ; VOLUMES ; RECIPIENTS ; BRONCHIOLITIS ; bronchiolitis obliterans ; lung transplantation ; pulmonary function ; PULMONARY-FUNCTION ; TRANSPLANT RECIPIENTS
    Abstract: The aim of this study was to evaluate the possible contribution of He-3-MRI to detect obliterative bronchiolitis (OB) in the follow-up of lung transplant recipients. Nine single- and double-lung transplanted patients were studied by an initial and a follow-up He-3-MRI study. Images were evaluated subjectively by estimation of ventilation defect area and quantitatively by individually adapted threshold segmentation and subsequent calculation of ventilated lung volume. Bronchiolitis obliterans syndrome (BOS) was diagnosed using pulmonary function tests. At He-3-MRI, OB was suspected if ventilated lung volume had decreased by 10% or more at the follow-up MRI study compared with the initial study. General accordance between pulmonary function testing and He-3-MRI was good, although subjective evaluation of He-3-MRI underestimated improvement in ventilation as obtained by pulmonary function tests. The He-3-MRI indicated OB in 6 cases. According to pulmonary function tests, BOS was diagnosed in 5 cases. All diagnoses of BOS were also detected by He-3-MRI. In 2 of these 5 cases, He-3-MRI indicated OB earlier than pulmonary function tests. The results support the hypothesis that He-3-MRI may be sensitive for early detection of OB and emphasize the need for larger prospective follow-up studies
    Type of Publication: Journal article published
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  • 3
    Keywords: evaluation ; Germany ; IN-VIVO ; LUNG ; CT ; DENSITY ; EMPHYSEMA ; imaging ; VOLUME ; DISEASE ; computed tomography ; PATIENT ; INDEX ; TRANSPLANTATION ; CONTRAST ; FLOW ; MRI ; magnetic resonance imaging ; FORM ; GAS ; tomography ; COMPUTED-TOMOGRAPHY ; HEALTHY ; HYPERPOLARIZED HE-3 ; DIFFUSION ; AIRWAY ; HRCT ; resonance imaging ; HIGH-RESOLUTION ; OBSTRUCTION ; lung transplantation ; FUNCTIONAL-CHARACTERIZATION ; AIRWAYS DISEASE ; apparent diffusion coefficient ; COEFFICIENT ; hyperpolarized (3)Helium ; lung function ; PULMONARY-FUNCTION TESTS
    Abstract: Purpose: To assess the emphysematous enlargement of distal airspaces and concomitant large and small airway disease using diffusion-weighted (3)Helium-magnetic resonance imaging (MRI), high-resolution computed tomography (HRCT), and lung function tests (LFT). Methods: Seven patients were examined after single lung transplantation (LTx) and 1 before double LTx for various forms of emphysema. Five patients after double LTx served as controls. Patients were assessed by (3)Helium-MRI (apparent diffusion coefficient [ADC]), HRCT (mean lung density [MLD], emphysema index [EI]), and LFT. Results: Transplanted lungs: mean ADC = 0.17 cm(2)/s, MLD -848 H, EI 22%. Emphysematous lungs: mean ADC = 0.33 cm(2)/s, MLD -922 H; EI = 54%. Good correlations were found between ADC and MLD (r = 0.6), EI (r = 0.8), intrathoracic gas volume (r = 0.7), forced expiratory volume in 1 second (r = 0.7), and forced expiratory flows (r = 0.7). In contrast, HRCT only provided moderate correlations with LFT (EI: r = 0.5; MLD: r [1e] 0.4). Conclusion: In this initial study, He-3-MRI yield good correlations with HRCT and agrees better than HRCT with the functional characterization of emphysema regarding hyperinflation, large and small airway disease as provided by LFT
    Type of Publication: Journal article published
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  • 4
    Keywords: BLOOD ; Germany ; LUNG ; PERFUSION ; imaging ; QUANTIFICATION ; VOLUME ; TIME ; BLOOD-FLOW ; blood flow ; FLOW ; HIGH-RESOLUTION MEASUREMENT ; MRI ; TRACER BOLUS PASSAGES ; MAGNETIC-RESONANCE ; magnetic resonance imaging ; AGE ; PARAMETERS ; SCINTIGRAPHY ; CONTRAST-ENHANCED MRI ; magnetic resonance imaging (MRI) ; QUANTITATIVE-ANALYSIS ; HEALTHY ; LUNG PERFUSION ; TRANSIT-TIME ; HEALTHY-VOLUNTEERS ; ARTERIAL ; INFLATION ; contrast-enhanced
    Abstract: Rationale and Objectives: The effect of breathholding on pulmonary perfusion remains largely unknown. The aim of this study was to assess the effect of inspiratory and expiratory breathhold on pulmonary perfusion using quantitative pulmonary perfusion magnetic resonance imaging (MRI). Methods and Results: Nine healthy volunteers (median age, 28 years; range, 20-45 years) were examined with contrast-enhanced time-resolved 3-dimensional pulmonary perfusion MRI (FLASH 313, TR/TE: 1.9/0.8 ms; flip angle: 40degrees; GRAPPA) during end-inspiratory and expiratory breathholds. The perfusion parameters pulmonary blood flow (PBF), pulmonary blood volume (PBV), and mean transit time (MTT) were calculated using the indicator dilution theory. As a reference method, end-inspiratory and expiratory phase-contrast (PC) MRI of the pulmonary arterial blood flow (PABF) was performed. Results: There was a statistically significant increase of the PBF (Delta = 182 mL/100mL/min), PBV (Delta = 12 mL/100 mL), and PABF (Delta = 0.5 L/min) between inspiratory and expiratory breathhold measurements (P 〈 0.0001). Also, the MTT was significantly shorter (Delta = -0.5 sec) at expiratory breathhold (P = 0.03). Inspiratory PBF and PBV showed a moderate correlation (r = 0.72 and 0.61, P less than or equal to0.008) with inspiratory PABF. Conclusion: Pulmonary perfusion during breathhold depends on the inspiratory level. Higher perfusion is observed at expiratory breathhold
    Type of Publication: Journal article published
    PubMed ID: 15654250
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  • 5
    Keywords: Germany ; LUNG ; CT ; SIGNAL ; COMPUTED-TOMOGRAPHY ; RECONSTRUCTION ; FEASIBILITY ; HELICAL CT ; DEVICES ; DIAPHRAGM ; SCANS ; respiratory gating ; laser sensor ; CCD camera ; free-breathing ; prospective gating
    Abstract: Purpose: The aim was to investigate the feasibility and image quality of prospective respiratory gating for 3-D computed tomography (CT) of the lung. Material and Methods: Eight anesthetized pigs underwent prospectively gated multidetector computed tomography using 2 devices: a charge-coupled device (CCD) camera and a laser sensor. The output signal of both gating devices was connected to the scanner instead of ECG unit. Inspiratory and expiratory images were obtained during "free-breathing" and analyzed in MPR mode for sharpness of bronchi, diaphragm and lung using a 4-point-score (1, excellent to 4, severe artifacts). Results: The CCD camera worked in all animals. Using the laser sensor, only 50% of expiratory scans could be acquired. All acquired images showed excellent sharpness (CCD camera vs. laser sensor) for trachea (1.1 +/- 0.3 vs. 1.3 +/- 0.5), bronchi (1.4 +/- 0.7 vs. 1.8 +/- 0.6), lung fissures (1.0 vs. 1.1 0.3), and lung parenchyma (1.0 +/- 0.2 vs. 1.4 +/- 0.6), and minor to major artifacts for diaphragm (1.5 +/- 0.8 vs. 2.0 +/- 1.0, P 〈 0.05) and pericardial lung structures (1.9 +/- 0.7 vs. 2.3 +/- 0.5). Conclusion: High image quality for inspiratory and expiratory scans was achieved by free-breathing 3-D CT of the lung using noncontact prospective respiratory gating
    Type of Publication: Journal article published
    PubMed ID: 16625110
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  • 6
    Keywords: Germany ; LUNG ; CT ; EMPHYSEMA ; HIGH-RESOLUTION CT ; QUANTIFICATION ; VOLUME ; PATIENT ; IMPACT ; REDUCTION ; SIMULATION ; PARAMETERS ; COMPUTED-TOMOGRAPHY ; OBSTRUCTIVE PULMONARY-DISEASE ; THIN-SECTION CT ; HELICAL CT ; RE ; multidetector CT ; LUNG-VOLUME ; low dose ; MULTISLICE CT ; 3-dimensional quantitative volumetric analysis ; ALPHA-1-ANTITRYPSIN DEFICIENCY ; dose simulation ; LUNG DENSITY-MEASUREMENTS ; MACROSCOPIC MORPHOMETRY ; multidetector computed tomography ; VOLUME REDUCTION
    Abstract: Purpose: Quantitative evaluation of the lung parenchyma might be impaired or unreliable by use of reduced-dose CT protocols. Aim of the study was to define the threshold where reduced dose has significant impact on quantitative emphysema parameters. Materials and Methods: Thirty patients with severe centrilobular emphysema underwent multidetector computed tomography (120 kV, 150 mAs). Original CT raw data were simulated using 10 mAs settings (10-100 SlMmAs). Quantitative analysis provided lung volume, emphysema volume, emphysema index, mean lung density, and 4 emphysema volume classes. Simulated low-dose results were compared with original acquisition. Results: Emphysema index showed no clinical relevant variation down to 30 SlMmAs. The large emphysema volume class was significantly different below 50 SlMmAs. The intermediate and small classes showed an overproportional variation below 50 SlMmAs. Conclusions: Dose reduction down to 30 SlMmAs is possible for clinical routine. Settings below 50 SlMmAs significantly alter the indetailed 3-dimensional emphysema quantification
    Type of Publication: Journal article published
    PubMed ID: 16778622
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  • 7
    Keywords: BLOOD, blood flow, blood volume, BLOOD-FLOW, CONTRAST, correlation, DIAGNOSIS, FLOW, Germany, HYPERT
    Abstract: Purpose: Pathological changes of the peripheral pulmonary arteries induce pulmonary arterial hypertension (PAH). Ann of this study was to quantitatively assess the effect of PAH on pulmonary perfusion by 3D-MR-perfusion techniques and to compare findings to healthy controls. Furthermore, quantitative perfusion data were correlated with invasive pressure measurements. Material and methods: Five volunteers and 20 PAH patients (WHO class II or III) were examined using a 1.5 T MR scanner. Measurement of pulmonary perfusion was done in an inspiratory breathhold (FLASH3D; 3.5 min x 1.9 mm x 4 min; TA per 3D dataset 1.5 s). Injection of contrast media (0. 1 mmol Gd-DTPA/k, BW) and image acquisition were started simultaneously. Evaluation of 3D perfusion was done using singular value decomposition. Lung borders were outlined manually. Each lung Volume was divided into three regions (anterior, middle, posterior), and the following parameters were assessed: Time-to-Peak (TTP), blood flow (PBF), blood volume (PBV), and mean transit time (NITT). In 10 patients invasive pulmonary artery pressure measurements were available and correlated to the perfusion measurements. Results: In both, controls and patients, an anterior-to-posterior gradient with higher PBF and PBV posterior was observed. In the posterior lung region, a significant difference (p 〈 0.05) was found for TTP (12 s versus 16 s) and MTT (4 s versus 6 s) between volunteers and patients. PBF and PBV were lower in patients than in Volunteers (i.e. dorsal regions: 124 versus 180 ml/100 ml/min and 10 versus 12 ml/ 100 ml), but the difference failed to be significant. The ratio of PBF and PBV between the posterior and the middle or ventral regions showed no difference between both groups. A moderate linear correlation between mean pulmonary arterial pressure (mPAP) and PBV (r= 0.51) and MTT (r = 0.56) was found. Conclusion: The only measurable effect of PAH on pulmonary perfusion is a prolonging of the MTT. There is only it moderate linear correlation of invasive mPAP with PBV and MTT. (c) 2006 Elsevier Ireland Ltd. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 17045440
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  • 8
    Keywords: AGE, Aorta, AORTIC REGURGITATION, ASCENDING AORTA, CARDIOVASCULAR MAGNETIC-RESONANCE, CINE MRI, cong
    Abstract: Background Evaluation of the severity and the follow-up of aortic insufficiency (AI) are important tasks in paediatric cardiology. Assessment is based on clinical and echocardiographic (ECHO) findings such as the configuration of the valve and the regurgitation fraction (RF). Objective The goal of this study was to evaluate MRI compared to ECHO for determination of clinical severity, valve morphology and RF. Materials and methods Thirty patients (age 3-27 years) with mild-to-severe AI were evaluated by clinical examination, ECHO (2-D and Doppler), and MRI at 1.5 T (2-D true-FISP cine short axis, phase-contrast flow in the ascending aorta). Results Both methods identified 13 bicuspid and 17 tricuspid valves. Good correlations between ECHO and cine MRI were found for ventricular mass, stroke volume, and ejection fraction. A good linear correlation was found for the RF determined by ECHO and phase-contrast MRI (r=0.7). The RF was 6% in mild AI, 17% in moderate AI, and 30% in severe AI. The different severity groups showed significantly different RF and it was possible to discriminate between clinical severity grades (P=0.01). Conclusion ECHO and MRI showed good agreement in evaluating morphology and function of the left ventricle. The clinical severity of the disease can be evaluated correctly using MRI
    Type of Publication: Journal article published
    PubMed ID: 17387466
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  • 9
    Keywords: Aorta, ASCENDING AORTA, BLOOD, blood flow, BLOOD-FLOW, bronchosystemic shunt, CINE MRI, ECG gating,
    Abstract: Purpose: Different ECG gating techniques are available for MR phase-contrast (PC) flow measurements. Until now no study has reported the impact of different ECG gating techniques on quantitative flow parameters. The goal was to evaluate the impact of the gating method and the breathing schema on the pulmonary, systemic and bronchosystemic circulation. Material and methods: Twenty volunteers were examined (1.5 T) with free breathing phase-contrast flow (PC-flow) measurements with prospective (free-prospective) and retrospective (free-retrospective) ECG gating. Additionally, expiratory breath-hold retrospective ECG gated measurements (bh-retrospective) were performed. Blood flow per minute; peak velocity and time to peak velocity were compared. The clinically important difference between the systemic and pulmonary circulation (bronchosystemic shunt) was calculated. Results: Blood flow per minute was lowest for free-prospective (6 l/min, pulmonary trunc) and highest for bh-retrospective measurements (6.9 l/min, pulmonary trunc). No clinically significant difference in peak velocity was assessed (82-83 cm/s pulmonary trunc, 109-113 cm/s aorta). Time to peak velocity was shorter for retro-gated free-retrospective and bh-retrospective than for pro-gated free-prospective. The difference between systemic and pulmonary measurements was least for the free-retrospective technique. Conclusion: The type of gating has a significant impact on flow measurements. Therefore, it is important to use the same ECG gating method, especially for follow-up examinations. Retrospective ECG gated free breathing measurements allow for the most precise assessment of the bronchosystemic blood flow and should be used in clinical routine. (C) 2006 Elsevier Ireland Ltd. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 17023135
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  • 10
    Keywords: -, BLOOD, blood flow, blood volume, BLOOD-FLOW, CONTRAST, CONTRAST-ENHANCED MRI, FLOW, Germany, HEAL
    Abstract: Purpose: Oxygen-enhanced magnetic resonance (MR)-ventilation imaging of the lung is based on the inhalation of a high concentration of oxygen (hyperoxia). However, the effect of hyperoxia on the pulmonary circulation is not yet fully understood. In this study the impact of hyperoxia on the pulmonary circulation was evaluated. Materials and Methods: Ten healthy volunteers were examined in a 1.5 T MRI system with contrast-enhanced perfusion MRI (saturation recovery 2D turboFLASH) of the lung and phase-contrast flow measurements in the pulmonary trunk. Both measurements were performed breathing room air (R-A) and, subsequently, 100% oxygen (15 L/mm) (O-2). Results: The perfusion measurements showed a significant difference between RA and 02 for the pulmonary blood flow (181 vs. 257 mL/min/100 mL, P = 0.04) and blood volume (14 vs. 21 mL/100 mL, P = 0.008). The mean transit time of the contrast bolus was not changed (P = 0.4) in the dorsal part of the lung, whereas it was significantly prolonged (P = 0.006) in the central part. The mean heart rate during flow measurements breathing RA (67 +/- 11 beats/min) and O-2 (61 +/- 12 beats/min) were not significantly different (P = 0.055). The average cardiac output (pulmonary trunk) was not significantly lower while breathing O-2 (R-A: 5.9 vs. O-2: 5.5 L/min, P = 0.054). Conclusion: Hyperoxia causes a significant increase and redistribution of the pulmonary perfusion, whereas it leads to a not significant decrease in cardiac output. Thus, for MR-perfusion and MR-flow measurements oxygen inhalation should be avoided, if possible. In the context of oxygen-enhanced MR-ventilation imaging of the lung the contribution of this effect needs to be further evaluated
    Type of Publication: Journal article published
    PubMed ID: 17414523
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