M Puderbach

Publications of M Puderbach

• Quantification of pulmonary microcirculation by dynamic contrast-enhanced magnetic resonance imaging: Comparison of four regularization methods.

  Authors: M Salehi Ravesh, G Brix, F B Laun, T A Kuder, M Puderbach, J Ley-Zaporozhan, S Ley, A Fieselmann, M F Herrmann, W Schranz, W Semmler, F Risse

  Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine. 03/2012;

  Tissue microcirculation can be quantified by a deconvolution analysis of concentration-time curves measured by dynamic contrast-enhanced magnetic resonance imaging. However, deconvolution is anTissue microcirculation can be quantified by a deconvolution analysis of concentration-time curves measured by dynamic contrast-enhanced magnetic resonance imaging. However, deconvolution is an ill-posed problem, which requires regularization of the solutions. In this work, four algebraic deconvolution/regularization methods were evaluated: truncated singular value decomposition and generalized Tikhonov regularization (GTR) in combination with the L-curve criterion, a modified LCC (GTR-MLCC), and a response function model that takes a-priori knowledge into account. To this end, dynamic contrast-enhanced magnetic resonance imaging data sets were simulated by an established physiologically reference model for different signal-to-noise ratios and measured on a 1.5-T system in the lung of 10 healthy volunteers and 20 patients. Analysis of both the simulated and measured dynamic contrast-enhanced magnetic resonance imaging datasets revealed that GTR in combination with the L-curve criterion does not yield reliable and clinically useful results. The three other deconvolution/regularization algorithms resulted in almost identical microcirculatory parameter estimates for signal-to-noise ratios > 10. At low signal-to-noise ratios levels (<10) typically occurring in pathological lung regions, GTR in combination with a modified L-curve criterion approximates the true response function much more accurately than truncated singular value decomposition and GTR in combination with response function model with a difference in accuracy of up to 76%. In conclusion, GTR in combination with a modified L-curve criterion is recommended for the deconvolution of dynamic contrast-enhanced magnetic resonance imaging curves measured in the lung parenchyma of patients with highly heterogeneous signal-to-noise ratios. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.

• [Moving pleural mass.]

  Authors: M Dadrich, T Schneider, M Puderbach, H U Kauczor, C-P Heußel

  Medizinische Klinik, Intensivmedizin und Notfallmedizin. 02/2012;

  A 74-year-old man with bronchial carcinoma underwent radiofrequency ablation (RFA) due to poor pulmonary function. Therefore non-enhanced computed tomography (CT) of the chest was performed on twoA 74-year-old man with bronchial carcinoma underwent radiofrequency ablation (RFA) due to poor pulmonary function. Therefore non-enhanced computed tomography (CT) of the chest was performed on two subsequent days. Besides the tumor, the CT scans showed a moving calcification in the pleural cavity. This extremely rare condition called thoracolithiasis is usually an incidental finding. Mostly it is asymptomatic and does not require any treatment. It should be considered as a differential diagnosis of a peripheral pulmonary nodule.

• In vivo monitoring of cystic fibrosis-like lung disease in mice by volumetric computed tomography.

  Authors: M O Wielpütz, M Eichinger, Z Zhou, K Leotta, S Hirtz, S H Bartling, W Semmler, H-U Kauczor, M Puderbach, M A Mall

  The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology. 04/2011; 38(5):1060-70.

  The onset and spontaneous development of cystic fibrosis (CF) lung disease remain poorly understood. In the present study, we used volumetric computed tomography (VCT) as a new method forThe onset and spontaneous development of cystic fibrosis (CF) lung disease remain poorly understood. In the present study, we used volumetric computed tomography (VCT) as a new method for longitudinal in vivo monitoring of early lesions and disease progression in CF-like lung disease in β-epithelial Na(+) channel (ENaC)-transgenic (TG) mice. Using a VCT scanner prototype (80 kV, 50 mA·s, scan time 19 s and spatial resolution 200 μm), βENaC-TG mice and wild-type (WT) littermates were examined longitudinally at 10 time-points from neonatal to adult ages, and VCT images were assessed by qualitative and quantitative morphological parameters. We demonstrate that VCT detected early-onset airway mucus obstruction, diffuse infiltrates, atelectasis and air trapping as characteristic abnormalities in βENaC-TG mice. Furthermore, we show that early tracheal mucus obstruction predicted mortality in βENaC-TG mice and that the density of lung parenchyma was significantly reduced at all time-points in βENaC-TG compared with WT mice (median ± sem -558 ± 8 HU in WT versus -686 ± 16 HU in βENaC-TG at 6 weeks of age; p < 0.005). Our study demonstrates that VCT is a sensitive, noninvasive technique for early detection and longitudinal monitoring of morphological abnormalities of CF-like lung disease in mice, and may thus provide a useful tool for pre-clinical in vivo evaluation of novel treatment strategies for CF.

• [Lung cancer staging].

  Authors: C Hintze, J Dinkel, J Biederer, C P Heussel, M Puderbach

  Der Radiologe. 02/2011; 51(2):135-44.

  Lung cancer is the third most frequent new cancer diagnosis in Germany. An elaborate clinical diagnosis is essential for successful therapy planning. The necessary examinations are defined in theLung cancer is the third most frequent new cancer diagnosis in Germany. An elaborate clinical diagnosis is essential for successful therapy planning. The necessary examinations are defined in the current S3 guideline on lung cancer diagnosis and therapy. A compilation of diagnostic reports has led to the current 7th edition of the TNM system. According to this update staging is carried out in terms of tumor extent, lymph node status and distant metastases. The resultant tumor stage forms the basis for individual therapy planning. Current guidelines as well as the current TNM system are presented. The usefulness of modern cross-sectional imaging and the possible modalities in this system is reported.

• [New procedures. Comprehensive staging of lung cancer by MRI].

  Authors: C Hintze, J Dinkel, J Biederer, C P Heussel, M Puderbach

  Der Radiologe. 08/2010; 50(8):699-705.

  Lung cancer staging according to the TNM system is based on morphological assessment of the primary cancer, lymph nodes and metastases. All aspects of this important oncological classification areLung cancer staging according to the TNM system is based on morphological assessment of the primary cancer, lymph nodes and metastases. All aspects of this important oncological classification are measurable with MRI. Pulmonary nodules can be detected at the clinically relevant size of 4-5 mm in diameter. The extent of mediastinal, hilar and supraclavicular lymph node affection can be assessed at the same time. The predominant metastatic spread to the adrenal glands and spine can be detected in coronal orientation during dedicated MRI of the lungs. Search focused whole body MRI completes the staging. Various additional MR imaging techniques provide further functional and clinically relevant information during a single examination. In the oncological context the most important techniques are imaging of perfusion and tumor motion. Functional MRI of the lungs complements the pure staging and improves surgical approaches and radiotherapy planning.

• A Hybrid Breath Hold and Continued Respiration-Triggered Technique for Time-Resolved 3D MRI Perfusion Studies in Lung Cancer.

  Authors: C Hintze, A Stemmer, M Bock, T Kuder, F Risse, J Dinkel, H Prüm, M Puderbach, C Fink, J Biederer, H U Kauczor

  RoFo : Fortschritte auf dem Gebiete der Rontgenstrahlen und der Nuklearmedizin. 10/2009;

  PURPOSE: Assessment of lung cancer perfusion is impaired by respiratory motion. Imaging times for contrast agent wash-out studies often exceed breath hold capabilities, and respiration triggeringPURPOSE: Assessment of lung cancer perfusion is impaired by respiratory motion. Imaging times for contrast agent wash-out studies often exceed breath hold capabilities, and respiration triggering reduces temporal resolution. Temporally resolved volume acquisition of entire tumors is required to assess heterogeneity. Therefore, we developed and evaluated an MR measurement technique that exceeds a single breath hold, and provides a variable temporal resolution during acquisition while suspending breath-dependent motion. MATERIALS AND METHODS: 20 patients with suspected lung cancer were subjected to perfusion studies using a spoiled 3D gradient echo sequence after bolus injection of 0.07 mmol/kg body weight of Gd-DTPA. 10 acquisitions in expiratory breath hold were followed by 50 navigator-triggered acquisitions under free breathing. Post-processing allowed for co-registration of the 3D data sets. An ROI-based visualization of the signal-time curves was performed. RESULTS: In all cases motion-suspended, time-resolved volume data sets (40 x 33 x 10 cm (3), voxel size: 2.1 x 2.1 x 5.0 mm (3)) were generated with a variable, initially high temporal resolution (2.25 sec) that was synchronized with the breath pattern and covered up to 8? min. In 7 / 20 cases a remaining offset could be reduced by rigid co-registration. The tumors showed fast wash-in, followed by rapid signal decay (8 / 20) or a plateau. CONCLUSION: The feasibility of a perfusion study with hybrid breath hold and navigator-triggered time-resolved 3D MRI which combines high initial temporal resolution during breath hold with a long wash-out period under free breathing was demonstrated.

• Lung hyperinflation: foe or friend?

  Authors: M Eichinger, S Walterspacher, T Scholz, K Tetzlaff, K Röcker, C M Muth, M Puderbach, H U Kauczor, S Sorichter

  The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology. 11/2008; 32(4):1113-6.

  Breath-hold divers employ glossopharyngeal insufflation (GI) in order to prevent the lungs from compressing at great depth and to increase intrapulmonary oxygen stores, thus increasing breath-holdBreath-hold divers employ glossopharyngeal insufflation (GI) in order to prevent the lungs from compressing at great depth and to increase intrapulmonary oxygen stores, thus increasing breath-hold time. The presented case study shows the physiological data and dynamic magnetic resonance imaging (dMRI) findings of acute hyperinflation, deliberately induced by GI, in a breath-hold diver and discusses the current state of knowledge regarding the associated hazards of this unique competitive sport. Static and dynamic lung volumes and expiratory flows were within the normal range, with vital capacity and peak expiratory flow being higher than the predicted values. Airway resistance and diffusing capacity of the lung for carbon monoxide were normal. Static compliance was normal and increased five-fold with hyperinflation. dMRI revealed a preserved shape of the thorax and diaphragm with hyperinflation. A herniation of the lung beneath the sternum and enlargement of the costodiaphragmatic angle were additional findings during the GI manoeuvre. After expiration, complete resolution to baseline was demonstrated. Hyperinflation can be physiological and even protective under abnormal physical conditions in the sense of acute adaptation to deep breath-hold diving. Dynamic magnetic resonance imaging is adequate for visualisation of the sequence of the glossopharyngeal insufflation manoeuvre and the complete reversibility of deliberate hyperinflation.

• Semiautomatic Assessment of Respiratory Motion in Dynamic MRI - Comparison with Simultaneously Acquired Spirometry.

  Authors: R Tetzlaff, M Eichinger, M Schöbinger, M Puderbach, H P Meinzer, H U Kauczor

  RoFo : Fortschritte auf dem Gebiete der Rontgenstrahlen und der Nuklearmedizin. 10/2008;

  PURPOSE: Supplementing global spirometry with regional information could allow for earlier and more specific diagnosis of lung disease. Dynamic magnetic resonance imaging (dMRI) makes it possible toPURPOSE: Supplementing global spirometry with regional information could allow for earlier and more specific diagnosis of lung disease. Dynamic magnetic resonance imaging (dMRI) makes it possible to derive functional parameters from the visualization of the pulmonary motion of single lungs. The aim of this study was to compare high temporal resolution measurements of left and right thoracic diameters to simultaneously acquired spirometry. MATERIALS AND METHODS: 10 healthy volunteers underwent 2-dimensional dMRI of both lungs at 1.5 T. Spirometry was performed simultaneously with an MRI-compatible spirometer. Thoracic diameters were measured semiautomatically and compared to simultaneously measured spirometric volumes. A dMRI surrogate for the Tiffeneau Index was compared to the spirometric Tiffeneau. RESULTS: The volume-time and flow-volume curves from dMRI were very similar to the spirometric curves. The semiautomatically measured diameters correlated well with the spirometric volumes (r > = 0.8, p < 10 - 15). Agreement between the methods at full temporal resolution was not as convincing (width of 95 % limits of agreement interval up to 56 %). Good agreement was found between the Tiffenau surrogate and spirometry (width of 95 % limits of agreement interval of 14.5 %). CONCLUSION: DMRI with semiautomatic measurement of thoracic diameters makes measurement of realistic volume-time and flow-volume curves from single lungs possible. The derived single lung Tiffeneau Index shows good agreement to spirometry and could be valuable to supplement global spirometric measurements with functional data from single lungs.

• MRI of respiratory dynamics with 2D steady-state free-precession and 2D gradient echo sequences at 1.5 and 3 Tesla: an observer preference study.

  Authors: M Fabel, B Wintersperger, O Dietrich, M Eichinger, C Fink, M Puderbach, H U Kauczor, S Schoenberg, J Biederer

  European radiology. 10/2008;

  To compare the image quality of dynamic lung MRI with variations of steady-state free-precession (SSFP) and gradient echo (GRE) cine techniques at 1.5 T and 3 T. Ventilated porcine lungs withTo compare the image quality of dynamic lung MRI with variations of steady-state free-precession (SSFP) and gradient echo (GRE) cine techniques at 1.5 T and 3 T. Ventilated porcine lungs with simulated lesions inside a chest phantom and four healthy human subjects were assessed with SSFP (TR/TE = 2.9/1.22 ms; 3 ima/s) and GRE sequences (TR/TE = 2.34/0.96 ms; 8 ima/s) as baseline at 1.5 and 3 T. Modified SSFPs were performed with nine to ten images/s (parallel imaging factors 2 and 3). Image quality for representative structures and artifacts was ranked by three observers independently. At 1.5 T, standard SSFP achieved the best image quality with superior spatial resolution and signal, but equal temporal resolution to GRE. SSFP with improved temporal resolution was ranked second best. Further acceleration (PI factor 3) was of no benefit, but increased artifacts. At 3 T, GRE outranged SSFP imaging with high lesion signal intensity, while artifacts on SSFP images increased visibly. At 1.5 T, a modified SSFP with moderate parallel imaging (PI factor 2) was considered the best compromise of temporal and spatial resolution. At 3 T, GRE sequences remain the best choice for dynamic lung MRI.

• MR imaging of the chest: a practical approach at 1.5T.

  Authors: M Puderbach, C Hintze, S Ley, M Eichinger, H U Kauczor, J Biederer

  European journal of radiology. 01/2008; 64(3):345-55.

  Magnetic resonance imaging (MRI) is capable of imaging infiltrative lung diseases as well as solid lung pathologies with high sensitivity. The broad use of lung MRI was limited by the long study timeMagnetic resonance imaging (MRI) is capable of imaging infiltrative lung diseases as well as solid lung pathologies with high sensitivity. The broad use of lung MRI was limited by the long study time as well as its sensitivity to motion and susceptibility artifacts. These disadvantages were overcome by the utilisation of new techniques such as parallel imaging. This article aims to propose a standard MR imaging protocol at 1.5T and presents a spectrum of indications. The standard protocol comprises non-contrast-enhanced sequences. Following a GRE localizer (2D-FLASH), a coronal T2w single-shot half-Fourier TSE (HASTE) sequence with a high sensitivity for infiltrates and a transversal T1w 3D-GRE (VIBE) sequence with a high sensitivity for small lesions are acquired in a single breath hold. Afterwards, a coronal steady-state free precession sequence (TrueFISP) in free breathing is obtained. This sequence has a high sensitivity for central pulmonary embolism. Distinct cardiac dysfunctions as well as an impairment of the breathing mechanism are visible. The last step of the basic protocol is a transversal T2w-STIR (T2-TIRM) in a multi-breath holds technique to visualize enlarged lymph nodes as well as skeletal lesions. The in-room time is approximately 15min. The extended protocol comprises contrast-enhanced sequences (3D-GRE sequence (VIBE) after contrast media; about five additional minutes). Indications are tumorous lesions, unclear (malignant) pleural effusions and inflammatory diseases (vaskulitis). A perfusion analysis can be achieved using a 3D-GRE in shared echo-technique (TREAT) with a high temporal resolution. This protocol can be completed using a MR-angiography (3D-FLASH) with high spatial resolution. The in-room time for the complete protocol is approximately 30min.

• Magnetic resonance-compatible-spirometry: principle, technical evaluation and application.

  Authors: M Eichinger, M Puderbach, H J Smith, R Tetzlaff, A Kopp-Schneider, M Bock, J Biederer, H U Kauczor

  The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology. 12/2007; 30(5):972-9.

  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 imageThe 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 (FEV(1)) and forced vital capacity (FVC) were calculated and a sample paired t-test and Bland-Altman plots were generated. A total of 11 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 FEV(1) 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 FEV(1) was found. FEV(1) 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.

• Reproducible Simulation of Respiratory Motion in Porcine Lung Explants.

  Authors: J Biederer, C Plathow, M Schoebinger, R Tetzlaff, M Puderbach, H Bolte, J Zaporozhan, H P Meinzer, M Heller, H U Kauczor

  RöFo : Fortschritte auf dem Gebiete der Röntgenstrahlen und der Nuklearmedizin. 12/2006; 178(11):1067-72.

  PURPOSE: To develop a model for exactly reproducible respiration motion simulations of animal lung explants inside an MR-compatible chest phantom. MATERIALS AND METHODS: The materials included aPURPOSE: To develop a model for exactly reproducible respiration motion simulations of animal lung explants inside an MR-compatible chest phantom. MATERIALS AND METHODS: The materials included a piston pump and a flexible silicone reconstruction of a porcine diaphragm and were used in combination with an established MR-compatible chest phantom for porcine heart-lung preparations. The rhythmic inflation and deflation of the diaphragm at the bottom of the artificial thorax with water (1 - 1.5 L) induced lung tissue displacement resembling diaphragmatic breathing. This system was tested on five porcine heart-lung preparations using 1.5T MRI with transverse and coronal 3D-GRE (TR/TE = 3.63/1.58, 256 x 256 matrix, 350 mm FOV, 4 mm slices) and half Fourier T2-FSE (TR/TE = 545/29, 256 x 192, 350 mm, 6 mm) as well as multiple row detector CT (16 x 1 mm collimation, pitch 1.5, FOV 400 mm, 120 mAs) acquired at five fixed inspiration levels. Dynamic CT scans and coronal MRI with dynamic 2D-GRE and 2D-SS-GRE sequences (image frequencies of 10/sec and 3/sec, respectively) were acquired during continuous "breathing" (7/minute). The position of the piston pump was visually correlated with the respiratory motion visible through the transparent wall of the phantom and with dynamic displays of CT and MR images. An elastic body splines analysis of the respiratory motion was performed using CT data. RESULTS: Visual evaluation of MRI and CT showed three-dimensional movement of the lung tissue throughout the respiration cycle. Local tissue displacement inside the lung explants was documented with motion maps calculated from CT. The maximum displacement at the top of the diaphragm (mean 26.26 [SD 1.9] mm on CT and 27.16 [SD 1.5] mm on MRI, respectively [p = 0.25; Wilcoxon test]) was in the range of tidal breathing in human patients. CONCLUSION: The chest phantom with a diaphragmatic pump is a promising platform for multi-modality imaging studies of the effects of respiratory lung motion.

• [MRI in mucoviscidosis (cystic fibrosis)]

  Authors: M Eichinger, M Puderbach, C P Heussel, H U Kauczor

  Der Radiologe. 05/2006; 46(4):275-6, 278-81.

  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 lungCystic 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 1990 s. 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.

• Time-resolved echo-shared parallel MRA of the lung: observer preference study of image quality in comparison with non-echo-shared sequences.

  Authors: C Fink, M Puderbach, S Ley, J Zaporozhan, C Plathow, H U Kauczor

  European radiology. 11/2005; 15(10):2070-4.

  The aim of this study was to evaluate the image quality of time-resolved echo-shared parallel MRA of the lung. The pulmonary vasculature of nine patients (seven females, two males; median age: 44The aim of this study was to evaluate the image quality of time-resolved echo-shared parallel MRA of the lung. The pulmonary vasculature of nine patients (seven females, two males; median age: 44 years) with pulmonary disease was examined using a time-resolved MRA sequence combining echo sharing with parallel imaging (time-resolved echo-shared angiography technique, or TREAT). The sharpness of the vessel borders, conspicuousness of peripheral lung vessels, artifact level, and overall image quality of TREAT was assessed independently by four readers in a side-by-side comparison with non-echo-shared time-resolved parallel MRA data (pMRA) previously acquired in the same patients. Furthermore, the SNR of pulmonary arteries (PA) and veins (PV) achieved with both pulse sequences was compared. The mean voxel size of TREAT MRA was decreased by 24% compared with the non-echo-shared MRA. Regarding the sharpness of the vessel borders, conspicuousness of peripheral lung vessels, and overall image quality the TREAT sequence was rated superior in 75-76% of all cases. If the TREAT images were preferred over the pMRA images, the advantage was rated as major in 61-71% of all cases. The level of artifacts was not increased with the TREAT sequence. The mean interobserver agreement for all categories ranged between fair (artifact level) and good (overall image quality). The maximum SNR of TREAT did not differ from non-echo-shared parallel MRA (PA: TREAT: 273+/-45; pMRA: 280+/-71; PV: TREAT: 273+/-33; pMRA: 258+/-62). TREAT achieves a higher spatial resolution than non-echo-shared parallel MRA which is also perceived as an improved image quality.

• Quantitative analysis of lung and tumour mobility: comparison of two time-resolved MRI sequences.

  Authors: C Plathow, M Klopp, C Fink, A Sandner, H Hof, M Puderbach, F Herth, A Schmähl, H U Kauczor

  The British journal of radiology. 09/2005; 78(933):836-40.

  The purpose of this study was to describe the use of parallel imaging technique (PAT) using dynamic MRI in lung and tumour mobility during the breathing cycle. 20 patients with stage I non-small cellThe purpose of this study was to describe the use of parallel imaging technique (PAT) using dynamic MRI in lung and tumour mobility during the breathing cycle. 20 patients with stage I non-small cell lung carcinoma were investigated using two dynamic gradient echo sequences with PAT (TrueFISP (fast imaging with steady precession), and fast low angle shot (FLASH). Craniocaudal distance from the apex to the diaphragm of the thorax and tumour mobility during the breathing cycle were measured. Signal-to-noise ratio (SNR) of the tumour was determined. In spite of the different temporal resolutions both trueFISP and FLASH sequence proved to be adequate to continuously measure lung motion and tumour mobility. SNR of the tumour was significantly higher using the trueFISP sequence than FLASH sequence (20.7+/-3.6 vs 5.8+/-2.3, p<0.01). Mobility of the tumour bearing hemithorax was significantly lower compared with the non-tumour bearing hemithorax (p<0.05). Dynamic MRI using PAT allows for continuous quantitative documentation of tumour mobility and lung motion. Because of the higher SNR, trueFISP sequence provides a better delineation of intrapulmonary lesions with a sufficient temporal resolution.

• [Contrast-enhanced 3D MR perfusion of the lung: application of parallel imaging technique in healthy subjects]

  Authors: S Ley, C Fink, M Puderbach, C Plathow, F Risse, K F Kreitner, H U Kauczor

  RöFo : Fortschritte auf dem Gebiete der Röntgenstrahlen und der Nuklearmedizin. 04/2004; 176(3):330-4.

  PURPOSE: Evaluation of lung perfusion by contrast-enhanced 3D MRI using partial parallel imaging techniques. MATERIALS AND METHODS: Eight healthy volunteers were examined using a contrast-enhancedPURPOSE: Evaluation of lung perfusion by contrast-enhanced 3D MRI using partial parallel imaging techniques. MATERIALS AND METHODS: Eight healthy volunteers were examined using a contrast-enhanced dynamic FLASH 3D sequence with partial parallel imaging technique at 1.5 T MRI with a TA of 1.5 sec. The whole lung was covered by 36 coronal slices. A ventral, middle and dorsal slice of each lung was manually segmented and signal-to-time curves were computed. For absolute quantification of blood flow through the right and left pulmonary artery, phase-contrast flow measurements were performed. RESULTS: No significant difference was found between the signal intensity in the right (8.9 +/- 2.6) and left (8.0 +/- 3.5) lung, corresponding to a left-to-right signal intensity ratio of 0.9. A significantly higher signal intensity was found in the dorsal regions of the lungs (p = 0.01) compared to the ventral regions. The time to peak of the signal intensity was significantly shorter in the dorsal (15.3 sec) and middle (15.7 sec) regions of the lungs (p = 0.03 and p = 0.04, respectively) than in the ventral regions (16.3 sec). The ratio between blood flow through the left (2.2 L/min) and right (2.7 L/min) lung was 0.84. CONCLUSION: Partial parallel image acquisition can assess the perfusion of the lungs at high temporal resolution. The perfusion is slightly higher on the right than on the left. The signal increases faster and has a higher peak in the dorsal lung regions.

• Quantitative analysis of pulmonary perfusion using time-resolved parallel 3D MRI - initial results.

  Authors: C Fink, F Risse, R Buhmann, S Ley, F J Meyer, C Plathow, M Puderbach, H U Kauczor

  RöFo : Fortschritte auf dem Gebiete der Röntgenstrahlen und der Nuklearmedizin. 03/2004; 176(2):170-4.

  PURPOSE: To assess the use of time-resolved parallel 3D MRI for a quantitative analysis of pulmonary perfusion in patients with cardiopulmonary disease. MATERIALS AND METHODS: Eight patients withPURPOSE: To assess the use of time-resolved parallel 3D MRI for a quantitative analysis of pulmonary perfusion in patients with cardiopulmonary disease. MATERIALS AND METHODS: Eight patients with pulmonary embolism or pulmonary hypertension were examined with a time-resolved 3D gradient echo pulse sequence with parallel imaging techniques (FLASH 3D, TE/TR: 0.8/1.9 ms; flip angle: 40 degrees; GRAPPA). A quantitative perfusion analysis based on indicator dilution theory was performed using a dedicated software. RESULTS: Patients with pulmonary embolism or chronic thromboembolic pulmonary hypertension revealed characteristic wedge-shaped perfusion defects at perfusion MRI. They were characterized by a decreased pulmonary blood flow (PBF) and pulmonary blood volume (PBV) and increased mean transit time (MTT). Patients with primary pulmonary hypertension or Eisenmenger syndrome showed a more homogeneous perfusion pattern. The mean MTT of all patients was 3.3 - 4.7 s. The mean PBF and PBV showed a broader interindividual variation (PBF: 104 - 322 ml/100 ml/min; PBV: 8 - 21 ml/100 ml). CONCLUSION: Time-resolved parallel 3D MRI allows at least a semi-quantitative assessment of lung perfusion. Future studies will have to assess the clinical value of this quantitative information for the diagnosis and management of cardiopulmonary disease.

• 3He-MRI-based vs. conventional determination of lung volumes in patients after unilateral lung transplantation: a new approach to regional spirometry.

  Authors: K Markstaller, H U Kauczor, M Puderbach, E Mayer, M Viallon, K Gast, N Weiler, M Thelen, B Eberle

  Acta anaesthesiologica Scandinavica. 08/2002; 46(7):845-52.

  BACKGROUND: To use 3Helium (3He)-MRI in patients with unilateral lung grafts to assess the contributions of graft and native lung to total ventilated lung volume, and second to compare conventionalBACKGROUND: To use 3Helium (3He)-MRI in patients with unilateral lung grafts to assess the contributions of graft and native lung to total ventilated lung volume, and second to compare conventional measurements of intrapulmonary gas volume (spirometry, body plethysmography) with image-based volumetry of ventilated lung parenchyma visualized by hyperpolarized 3He-MRI. METHODS: With Ethics Committee approval, five patients with single lung transplantation (SLTX) for idiopathic pulmonary fibrosis (IPF) underwent both conventional pulmonary function testing (PFT) and 3He-MRI of the lung. Intrapulmonary gas volume (GV) during the inspiratory breathhold for 3He-MRI was calculated from measured functional residual capacity (corrected for supine position) and inspired tidal volume. Image-based global and regional lung volumetries (LV) were performed in three-dimensionally reconstructed 3He-MR images (corrected for the fraction of tissue and blood). RESULTS: Transplanted lungs were characterized by a homogeneous distribution of signal intensity, whereas the native lungs of the patients suffering from IPF displayed an inhomogeneous signal distribution pattern with numerous round or wedge-shaped ventilation defects. Total ventilated lung volume determined by 3He-MRI correlated well with PFT-based measurements, but with a systematic overestimation of the 3He-based lung volumetry of approximately 20%. Functioning lung grafts contributed 66+/-6% and their corresponding native IPF lungs 34+/-6% to total ventilated volume (P<0.05; mean+/-SD). CONCLUSION: 3Helium-MRI of the lung offers a novel approach to regional determination of ventilated lung volume, including its blood and tissue compartments. The advantage of this technique over computed tomography or ventilation scintigraphy is the lack of radiation exposure, and hence its repeatability. Follow up of SLTX patients with this new technique may allow the monitoring of functional and structural developments of grafted lungs with better sensitivity and specificity than PFT.

• Volumetry of ventilated airspaces by 3He MRI: preliminary results.

  Authors: H U Kauczor, K Markstaller, M Puderbach, J Lill, B Eberle, G Hanisch, T Grossmann, C P Heussel, W Schreiber, M Thelen

  Investigative radiology. 03/2001; 36(2):110-4.

  RATIONALE AND OBJECTIVES: To develop a validated post-processing routine for volumetry of the ventilated airspaces by 3He MRI. METHODS: 3Helium MRI and pulmonary function tests were performed inRATIONALE AND OBJECTIVES: To develop a validated post-processing routine for volumetry of the ventilated airspaces by 3He MRI. METHODS: 3Helium MRI and pulmonary function tests were performed in seven healthy volunteers. After segmentation of ventilated airspaces, their volumes were calculated. Functional residual capacity (FRC) was used as a reference. For comparison of absolute volumes, correction factors were evaluated. RESULTS: Mean lung volume (+/- standard deviation) calculated from 3He MRI was 4,082 +/- 908 mL and mean FRC was 3,696 +/- 1166 mL, with a mean difference of 386 mL (r = 0.88). After correction for the relative pulmonary air content (factor 0.82), posture (0.72), and the individual tidal volume, 3He MRI volume was 3,348 +/- 744 mL and mean FRC was 3,422 +/- 817 mL, with the mean difference down to -74 mL (r = 0.9). Comparison on an individual basis confirmed an improvement in the estimation of absolute lung volume. CONCLUSIONS: Volumetry of ventilated lung from 3He MRI shows high correlation and good agreement with the results of pulmonary function tests.

• (3)He MRI in healthy volunteers: preliminary correlation with smoking history and lung volumes.

  Authors: D Guenther, B Eberle, J Hast, J Lill, K Markstaller, M Puderbach, W G Schreiber, G Hanisch, C P Heussel, R Surkau, T Grossmann, N Weiler, M Thelen, H U Kauczor

  NMR in biomedicine. 06/2000; 13(4):182-9.

  MRI with hyperpolarized helium-3 ((3)He) provides high-resolution imaging of ventilated airspaces. The first aim of this (3)He-study was to compare observations of localized signal defects in healthyMRI with hyperpolarized helium-3 ((3)He) provides high-resolution imaging of ventilated airspaces. The first aim of this (3)He-study was to compare observations of localized signal defects in healthy smokers and non-smokers. A second aim was to describe relationships between parameters of lung function, volume of inspired (3)He and signal-to-noise ratio. With Ethics Committee approval and informed consent, 12 healthy volunteers (seven smokers and five non-smokers) were studied. Imaging was performed in a 1.5 T scanner using a two-dimensional FLASH sequence at 30V transmitter amplitude (TR/TE/alpha = 11 ms/4.2 ms/<10 degrees ). Known amounts of (3)He were inhaled from a microprocessor-controlled delivery device and imaged during single breath-holds. Images were evaluated visually, and scored using a prospectively defined 'defect-index'. Signal-to-noise ratio of the images were correlated with localization, (3)He volumes and static lung volumes. Due to poor image quality studies of two smokers were not eligible for the evaluation. Smokers differed from non-smokers in total number and size of defects: the 'defect-index' of smokers ranged between 0.8 and 6.0 (median = 1.1), that of non-smokers between 0.1 and 0.8 (median = 0.4). Intraindividually, an anteroposterior gradient of signal-to-noise ratio was apparent. Signal-to-noise ratio correlated with the estimated amount of hyperpolarization administered (r = 0. 77), but not with static lung volumes. We conclude that (3)He MRI is a sensitive measure to detect regional abnormalities in the distribution of ventilation in clinically healthy persons with normal pulmonary function tests.