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Lung Perfusion (lung + perfusion)
Selected AbstractsLung perfusion studies after transcatheter closure of persistent ductus arteriosus with the Amplatzer duct occluder,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 3 2010Tugcin Bora Polat MD Abstract Background: Reduced left lung perfusion has been described after transcatheter closure of the patent ductus arteriosus (PDA) with several prostheses. Although the Amplatzer ductal occluder (ADO) device is currently the most widely used occluder for closure of large-sized PDAs, the potential consequences of flow distribution to the lungs of this device have not been completely clarified. We evaluated lung perfusion following occlusion of PDA with the ADO device. Methods: Forty-seven patients underwent successful transcatheter PDA occlusion using the ADO device were included in this study. Lung perfusion scans were performed 6 months after the procedure. Results: Decreased perfusion to the left lung (defined as < 40% of total lung flow) was observed in 17 patients (36%), 5 of whom were low-weight symptomatic infants. Ductal ampulla length was significantly shorter and minimal ductal diameter to ampulla diameter ratio was significantly higher in patients with decreased left lung perfusion and correlated well with left lung perfusion values (r = 0.516 and r = ,0.501, respectively). A cut-off value of ,5.8 mm for the ductal ampulla length and ,1.9 for ampulla diameter to ampulla length ratio showed high sensitivity and specificity for reduced lung perfusion. Conclusions: The incidence of abnormal left lung perfusion is high 6 months after transcatheter closure of PDA with the ADO, more likely in the low weight symptomatic infants and in patients with a short duct or a relatively shallow duct having abrupt narrowing of a large ampulla. © 2010 Wiley-Liss, Inc. [source] Scintigraphic evaluation of intrapulmonary shunt in normoxemic cirrhotic patients and effects of terlipressinHEPATOLOGY RESEARCH, Issue 10 2010George Kalambokis Aim:, The magnitude of intrapulmonary shunt (IPS) in cirrhotic patients without hypoxemia remains undefined. We evaluated the severity and clinical correlations of IPS in normoxemic cirrhotics, and possible IPS alterations after terlipressin treatment. Methods:, Fifteen patients with alcoholic cirrhosis without hypoxemia were studied at baseline and after the administration of 2 mg of terlipressin. The IPS fraction was evaluated by lung perfusion scan after the i.v. injection of technetium-99m -labeled macroaggregated albumin (99mTc-MAA) and calculation of brain uptake (positive value ,6%). Cardiac output (CO), pulmonary artery systolic pressure (PASP) and pulmonary vascular resistance (PVR) were evaluated by Doppler echocardiography. Mean arterial pressure (MAP) was measured and the ratio MAP/CO was calculated as an index of systemic vascular resistance (SVR). Portal vein velocity (PVV) and portal venous flow (PVF) were also assessed by Doppler ultrasonography. Results:, Three patients (20%) had an IPS fraction of more than 6%. A significant inverse correlation with platelet count (P = 0.001) and a direct correlation with Child,Pugh score (P = 0.06), PVV (P = 0.07) and PVF (P = 0.07) were noted. IPS fractions decreased significantly after terlipressin administration (P = 0.00001); the IPS fraction fell below 6% in all three patients with positive baseline values. Terlipressin treatment induced a significant decrease in CO (P = 0.003) and significant increases in MAP (P = 0.0003), SVR (P = 0.0003), SPAP (P = 0.001) and PVR (P = 0.01). Conclusion:, IPS fractions detected by 99mTc-MAA lung scan were inversely correlated with platelet count and directly with liver disease severity, and found abnormal in 20% of normoxemic cirrhotic patients. Terlipressin reduced significantly the magnitude of the shunt. [source] Iloprost inhalation redistributes pulmonary perfusion and decreases arterial oxygenation in healthy volunteersACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2009D. RIMEIKA Background: Previous studies have shown that ventilation,perfusion matching is improved in the prone as compared with that in the supine position. Regional differences in the regulation of vascular tone may explain this. We have recently demonstrated higher production of nitric oxide in dorsal compared with ventral human lung tissue. The purpose of the present study was to investigate regional differences in actions by another vasoactive mediator, namely prostacyclin. The effects on gas exchange and regional pulmonary perfusion in different body positions were investigated at increased prostacyclin levels by inhalation of a synthetic prostacyclin analogue and decreased prostacyclin levels by unselective cyclooxygenase (COX) inhibition. Methods: In 19 volunteers, regional pulmonary perfusion in the prone and supine position was assessed by single photon emission computed tomography using 99mTc macro-aggregated albumin before and after inhalation of iloprost, a stable prostacyclin analogue, or an intravenous infusion of a non-selective COX inhibitor, diclofenac. In addition, gas distribution was assessed in seven subjects using 99mTc-labelled ultra-fine carbon particles before and after iloprost inhalation in the supine position. Results: Iloprost inhalation decreased arterial PaO2 in both prone (from 14.2±0.5 to 11.7±1.7 kPa, P<0.01) and supine (from 13.7±1.4 to 10.9±2.1 kPa, P<0.01) positions. Iloprost inhalation redistributed lung perfusion from non-dependent to dependent lung regions in both prone and supine positions, while ventilation in the supine position was distributed in the opposite direction. No significant effects of non-selective COX inhibition were found in this study. Conclusions: Iloprost inhalation decreases arterial oxygenation and results in a more gravity-dependent pulmonary perfusion in both supine and prone positions in healthy humans. [source] Quantitative contrast-enhanced perfusion measurements of the human lung using the prebolus approachJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2009Markus Oechsner MS Abstract Purpose To investigate dynamic contrast-enhanced MRI (DCE-MRI) for quantification of pulmonary blood flow (PBF) and blood volume (PBV) using the prebolus approach and to compare the results to the global lung perfusion (GLP). Materials and Methods Eleven volunteers were examined by applying different contrast agent doses (0.5, 1.0, 2.0, and 3.0 mL gadolinium diethylene triamine pentaacetic acid [Gd-DTPA]), using a saturation-recovery (SR) true fast imaging with steady precession (TrueFISP) sequence. PBF and PBV were determined for single bolus and prebolus. Region of interest (ROI) evaluation was performed and parameter maps were calculated. Additionally, cardiac output (CO) and lung volume were determined and GLP was calculated as a contrast agent,independent reference value. Results The prebolus results showed good agreement with low-dose single-bolus and GLP: PBF (mean ± SD in units of mL/minute/100 mL) = single bolus 190 ± 73 (0.5-mL dose) and 193 ± 63 (1.0-mL dose); prebolus 192 ± 70 (1.0,2.0-mL dose) and 165 ± 52 (1.0,3.0-mL dose); GLP (mL/minute/100 mL) = 187 ± 34. Higher single-bolus resulted in overestimated values due to arterial input function (AIF) saturation. Conclusion The prebolus approach enables independent determination of appropriate doses for AIF and tissue signal. Using this technique, the signal-to-noise ratio (SNR) from lung parenchyma can be increased, resulting in improved PBF and PBV quantification, which is especially useful for the generation of parameter maps. J. Magn. Reson. Imaging 2009;30:104,111. © 2009 Wiley-Liss, Inc. [source] Design and testing of biological scaffolds for delivering reparative cells to target sites in the lung,JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 4 2010Edward P. Ingenito Abstract This study summarizes the development and testing of a scaffold to promote engraftment of cells in the distal lung. A fibrinogen,fibronectin,vitronectin hydrogel (FFVH) was developed and optimized with respect to its mechanical and biological properties for this application. In vitro, FFVH scaffolds promoted attachment, histiotypic growth and expression of basement membrane proteins by primary ovine lung mesenchymal cells derived from lung biopsies. In vivo testing was then performed to assess the ability of FFVHs to promote cell engraftment in the sheep lung. Treatment with autologous cells delivered using FFVH was clinically well tolerated. Cells labelled with a fluorescent dye (PKH-26) were detected at treatment sites after 1 month. Tissue mass (assessed by CT imaging) and lung perfusion (assessed by nuclear scintigraphy) were increased at emphysema test sites. Post-treatment histology demonstrated cell proliferation and increased elastin expression without scarring or collapse. No treatment-related pathology was observed at healthy control sites. FFVH scaffolds promote cell attachment, spreading and extracellular matrix expression in vitro and apparent engraftment in vivo, with evidence of trophic effects on the surrounding tissue. Scaffolds of this type may contribute to the development of cell-based therapies for patients with end-stage pulmonary diseases. Copyright © 2009 John Wiley & Sons, Ltd. [source] Non-contrast-enhanced perfusion and ventilation assessment of the human lung by means of fourier decomposition in proton MRIMAGNETIC RESONANCE IN MEDICINE, Issue 3 2009Grzegorz Bauman Abstract Assessment of regional lung perfusion and ventilation has significant clinical value for the diagnosis and follow-up of pulmonary diseases. In this work a new method of non-contrast-enhanced functional lung MRI (not dependent on intravenous or inhalative contrast agents) is proposed. A two-dimensional (2D) true fast imaging with steady precession (TrueFISP) pulse sequence (TR/TE = 1.9 ms/0.8 ms, acquisition time [TA] = 112 ms/image) was implemented on a 1.5T whole-body MR scanner. The imaging protocol comprised sets of 198 lung images acquired with an imaging rate of 3.33 images/s in coronal and sagittal view. No electrocardiogram (ECG) or respiratory triggering was used. A nonrigid image registration algorithm was applied to compensate for respiratory motion. Rapid data acquisition allowed observing intensity changes in corresponding lung areas with respect to the cardiac and respiratory frequencies. After a Fourier analysis along the time domain, two spectral lines corresponding to both frequencies were used to calculate the perfusion- and ventilation-weighted images. The described method was applied in preliminary studies on volunteers and patients showing clinical relevance to obtain non-contrast-enhanced perfusion and ventilation data. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc. [source] Normothermic Ex Vivo Perfusion Prevents Lung Injury Compared to Extended Cold Preservation for TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 10 2009M. Cypel Treatment of injured donor lungs ex vivo to accelerate organ recovery and ameliorate reperfusion injury could have a major impact in lung transplantation. We have recently demonstrated a feasible technique for prolonged (12 h) normothermic ex vivo lung perfusion (EVLP). This study was performed to examine the impact of prolonged EVLP on ischemic injury. Pig donor lungs were cold preserved in Perfadex® for 12 h and subsequently divided into two groups: cold static preservation (CSP) or EVLP at 37°C with SteenÔ solution for a further 12 h (total 24 h preservation). Lungs were then transplanted and reperfused for 4 h. EVLP preservation resulted in significantly better lung oxygenation (PaO2 531 ± 43 vs. 244 ± 49 mmHg, p < 0.01) and lower edema formation rates after transplantation. Alveolar epithelial cell tight junction integrity, evaluated by zona occludens-1 protein staining, was disrupted in the cell membranes after prolonged CSP but not after EVLP. The maintenance of integrity of barrier function during EVLP translates into significant attenuation of reperfusion injury and improved graft performance after transplantation. Integrity of functional metabolic pathways during normothermic perfusion was confirmed by effective gene transfer and GFP protein synthesis by lung alveolar cells. In conclusion, EVLP prevents ongoing injury associated with prolonged ischemia and accelerates lung recovery. [source] Lung perfusion studies after transcatheter closure of persistent ductus arteriosus with the Amplatzer duct occluder,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 3 2010Tugcin Bora Polat MD Abstract Background: Reduced left lung perfusion has been described after transcatheter closure of the patent ductus arteriosus (PDA) with several prostheses. Although the Amplatzer ductal occluder (ADO) device is currently the most widely used occluder for closure of large-sized PDAs, the potential consequences of flow distribution to the lungs of this device have not been completely clarified. We evaluated lung perfusion following occlusion of PDA with the ADO device. Methods: Forty-seven patients underwent successful transcatheter PDA occlusion using the ADO device were included in this study. Lung perfusion scans were performed 6 months after the procedure. Results: Decreased perfusion to the left lung (defined as < 40% of total lung flow) was observed in 17 patients (36%), 5 of whom were low-weight symptomatic infants. Ductal ampulla length was significantly shorter and minimal ductal diameter to ampulla diameter ratio was significantly higher in patients with decreased left lung perfusion and correlated well with left lung perfusion values (r = 0.516 and r = ,0.501, respectively). A cut-off value of ,5.8 mm for the ductal ampulla length and ,1.9 for ampulla diameter to ampulla length ratio showed high sensitivity and specificity for reduced lung perfusion. Conclusions: The incidence of abnormal left lung perfusion is high 6 months after transcatheter closure of PDA with the ADO, more likely in the low weight symptomatic infants and in patients with a short duct or a relatively shallow duct having abrupt narrowing of a large ampulla. © 2010 Wiley-Liss, Inc. [source] The Lung Is The Major Site That Produces Nitric Oxide To Induce Acute Pulmonary Oedema In Endotoxin ShockCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 4 2001Ru Ping Lee SUMMARY 1. The present study was undertaken to determine the locus of nitric oxide (NO) production that is toxic to the lung and produces acute pulmonary oedema in endotoxin shock, to examine and compare the effects of changes in lung perfusate on endotoxin-induced pulmonary oedema (EPE) and to evaluate the involvement of constitutive and inducible NO synthase (cNOS and iNOS, respectively). 2. Experiments were designed to induce septic shock in anaesthetized rats with the administration of Escherichia coli lipopolysaccharide (LPS). Exhaled NO, lung weight (LW)/bodyweight (BW) ratio, LW gain (LWG) and lung histology were measured and observed to determine the degree of EPE 4 h following LPS. The EPE was compared between groups in which LPS had been injected either into the systemic circulation or into the isolated perfused lung. The lung perfusate was altered from whole blood to physiological saline solution (PSS) with 6% albumin to test whether different lung perfusions affected EPE. Pretreatment with various NOS inhibitors was undertaken 10 min before LPS to investigate the contribution of cNOS and iNOS to the observed effects. 3. Endotoxin caused profound systemic hypotension, but little change in pulmonary arterial pressure. The extent of EPE was not different between that induced by systemic injection and that following administration to isolated lungs preparations. Replacement of whole blood with PSS greatly attenuated (P < 0.05) EPE. In blood-perfused lungs, pretreatment with NOS inhibitors, such as N, -nitro- L -arginine methyl ester, aminoguanidine and dexamethasone, significantly prevented EPE (P < 0.05). 4. The major site of NO production through the whole blood is in the lung. The NO production mediated by the iNOS system is toxic to the endothelium in the pulmonary microvasculature. Inhalation of NO for patients with sepsis may be used with clinical caution. Therapeutic consideration of lung extracorporeal perfusion with PSS and pharmacological pretreatment with iNOS inhibitors may be warranted. [source] Assessment and compensation of susceptibility artifacts in gradient echo MRI of hyperpolarized 3He gasMAGNETIC RESONANCE IN MEDICINE, Issue 2 2003Jim M. Wild Abstract The effects of macroscopic background field gradients upon 2D gradient echo images of inhaled 3He in the human lung were investigated at 1.5 T. Effective compensation of in-slice signal loss in 3He gradient echo images was then demonstrated using a multiple acquisition interleaved single gradient echo sequence. This method restores signal dephasing through a combination of separate images acquired with different slice refocusing gradients. In vivo imaging of volunteers with the sequence shows substantial restoration of signal at the lung periphery and close to blood vessels. The technique presented may be useful when using 3He MRI for volumetric measurements of lung ventilation and in studies using 3He combined with intravenous contrast as a means of assessing lung ventilation/perfusion (V/Q). Magn Reson Med 50:417,422, 2003. © 2003 Wiley-Liss, Inc. [source] | ||||||||||