Correlation of Regional Lung Ventilation and Gas Transfer to Red Blood Cells: Implications for Functional-Avoidance Radiation Therapy Planning.

PURPOSE: To investigate the degree to which lung ventilation and gas exchange are regionally correlated, using the emerging technology of hyperpolarized (HP)-129Xe magnetic resonance imaging (MRI). METHODS AND MATERIALS: Hyperpolarized-129Xe MRI studies were performed on 17 institutional review board-approved human subjects, including 13 healthy volunteers, 1 emphysema patient, and 3 non-small cell lung cancer patients imaged before and approximately 11 weeks after radiation therapy (RT). Subjects inhaled 1 L of HP-129Xe mixture, followed by the acquisition of interleaved ventilation and gas exchange images, from which maps were obtained of the relative HP-129Xe distribution in three states: (1) gaseous, in lung airspaces; (2) dissolved interstitially, in alveolar barrier tissue; and (3) transferred to red blood cells (RBCs), in the capillary vasculature. The relative spatial distributions of HP-129Xe in airspaces (regional ventilation) and RBCs (regional gas transfer) were compared. Further, we investigated the degree to which ventilation and RBC transfer images identified similar functional regions of interest (ROIs) suitable for functionally guided RT. For the RT patients, both ventilation and RBC functional images were used to calculate differences in the lung dose-function histogram and functional effective uniform dose. RESULTS: The correlation of ventilation and RBC transfer was ρ = 0.39 ± 0.15 in healthy volunteers. For the RT patients, this correlation was ρ = 0.53 ± 0.02 before treatment and ρ = 0.39 ± 0.07 after treatment; for the emphysema patient it was ρ = 0.24. Comparing functional ROIs, ventilation and RBC transfer demonstrated poor spatial agreement: Dice similarity coefficient = 0.50 ± 0.07 and 0.26 ± 0.12 for the highest-33%- and highest-10%-function ROIs in healthy volunteers, and in RT patients (before treatment) these were 0.58 ± 0.04 and 0.40 ± 0.04. The average magnitude of the differences between RBC- and ventilation-derived functional effective uniform dose, fV20Gy, fV10Gy, and fV5Gy were 1.5 ± 1.4 Gy, 4.1% ± 3.8%, 5.0% ± 3.8%, and 5.3% ± 3.9%, respectively. CONCLUSION: Ventilation may not be an effective surrogate for true regional lung function for all patients.

Time course and predictive factors for lung volume reduction following stereotactic ablative radiotherapy (SABR) of lung tumors.

BACKGROUND: Stereotactic ablative volume reduction (SAVR) is a potential alternative to lung-volume reduction surgery in patients with severe emphysema and excessive surgical risk. Having previously observed a dose-volume response for localized lobar volume reduction after stereotactic ablative radiotherapy (SABR) for lung tumors, we investigated the time course and factors associated with volume reduction. METHODS: We retrospectively identified 70 eligible patients receiving lung tumor SABR during 2007-2013. We correlated lobar volume reduction (relative to total, bilateral lung volume [TLV]) with volume receiving high biologically effective doses (VXXBED3) and other pre-treatment factors in all patients, and measured the time course of volume changes on 3-month interval CT scans in patients with large V60BED3 (n = 21, V60BED3 ≥4.1 % TLV). RESULTS: Median CT follow-up was 15 months. Median volume reduction of treated lobes was 4.5 % of TLV (range 0.01-13.0 %), or ~9 % of ipsilateral lung volume (ILV); median expansion of non-target adjacent lobes was 2.2 % TLV (-4.6-9.9 %; ~4 % ILV). Treated lobe volume reduction was significantly greater with larger VXXBED3 (XX = 20-100 Gy, R (2) = 0.52-0.55, p < 0.0001) and smaller with lower pre-treatment FEV1% (R (2) = 0.11, p = 0.005) in a multivariable linear model. Maximum volume reduction was reached by ~12 months and persisted. CONCLUSIONS: We identified a multivariable model for lobar volume reduction after SABR incorporating dose-volume and pre-treatment FEV1% and characterized its time course.

The complex association of metabolic syndrome and its components with computed tomography-determined emphysema index.

BACKGROUND: Recent reports have suggested the association between emphysema and cardiovascular disease (CVD); however, there are few reports regarding association of emphysema severity with metabolic syndrome and its components representing CVD risk factors. METHODS: A retrospective cross-sectional study was performed in 2814 adult male subjects over age 40 who visited the Health Promotion Center in Samsung Medical Center for a health checkup program. RESULTS: We classified patients according to the quintiles of forced expiratory volume in 1 sec (FEV1) and emphysema index (EI). FEV1 percentage predicted values (% pred) was inversely associated with prevalence of metabolic syndrome and most of its components, such as abdominal obesity, hypertension, fasting hyperglycemia, and low high-density lipoprotein cholesterol. Although there was no association between prevalence of metabolic syndrome and EI, hypertension was positively associated with EI (P<0.001) and high triglycerides (TGs) were inversely associated with EI (P=0.021). These associations persisted after adjustment of other variables (P<0.001 in hypertension and P=0.039 in high TGs). CONCLUSION: The computed tomography-determined EI has a complex association with components of metabolic syndrome that is associated with increased prevalence of hypertension but decreased prevalence of high TGs, whereas FEV1 (% pred) has an inverse association with metabolic syndrome and most of its components with consistent direction.

Efeito da laserterapia de baixa potência na inflamação pulmonar em rattus novergicus / Effect of low level laser therapy on lung inflammation in rattus norvegicus

Introdução. A doença pulmonar obstrutiva crônica é uma enfermidade respiratória caracterizada pela presença de obstrução crônica do fluxo aéreo e manifestação inflamatória. Objetivo. Verificar o efeito da laserterapia de baixa potência no tratamento da inflamação pulmonar. Metodologia. Utilizou-se 30 ratos, divididos em três grupos de dez animais: grupo controle (recebeu apenas ar ambiente); grupo DPOC e grupo DPOC+laser (expostos à fumaça de cigarro durante 45 dias, sendo o grupo DPOC+laser tratado durante 12 dias com laser 904nm). Para análise dos resultados foi realizada histopatologia. Resultados. O grupo controle apresentou espaços aéreos normais com distorção arquitetural periférica do pulmão, o grupo DPOC demonstrou um enfisema acentuado, áreas de atelectasias e destruição das paredes alveolares. O grupo tratado houve uma regressão de enfisema acentuado para discreto. Conclusão. Na análise realizada, a inflamação pulmonar induzida pelo cigarro pode ser comprovada e a laserterapia de baixa potência mostrou-se eficaz na atenuação da inflamação.

Introduction. The chronic obstructive pulmonary disease is a respiratory disease characterized by chronic airflow obstruction and inflammatory manifestation. Objective. To investigate the effect of low level laser therapy in the treatment of pulmonary inflammation. Methodology. We used 30 rats divided into three groups of ten animals: control group (received only room air), group COPD and COPD + laser (exposed to cigarette smoke for 45 days with group COPD + laser treated for 12 days with 904nm laser). For data analysis was performed histopathology. Results. The control group had normal air spaces with architectural distortion of the peripheral lung, COPD group showed a marked emphysema, areas of atelectasis and destruction of alveolar walls in the treated group there was a regression from mild to severe emphysema. Conclusion. Through the analysis performed pulmonary inflammation induced by cigarette can be proved, and the low level laser therapy was effective in reducing inflammation.