Regional Lung Function in Patients with Obstructive Lung Diseases

Gaziano, Dominic; Seaton, Anthony; Ogilvie, Colin

doi:10.1136/bmj.2.5705.330

Cited by 14 publications

(9 citation statements)

References 14 publications

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“…Moreover, because it also revealed statistically significant differences between symptomatic and asymptomatic smokers, this study demonstrates that the standard deviation of Pao 2 measurement can help detect more serious functional abnormalities as well. Although the observation of altered function does not unequivocally prove that these alterations are related to the subsequent development of disease, the results agree with the findings of many other imaging studies, which have demonstrated greater heterogeneity in ventilation (35,36), perfusion (37)(38)(39), and ventilation-perfusion mismatch (40,41) in smokers and patients with COPD. A recent hyperpolarized 3 He study also showed heterogeneous intrapulmonary oxygen tension in patients with bronchiolitis obliterans syndrome (42).…”

Section: Discussionsupporting

confidence: 81%

Alterations of Regional Alveolar Oxygen Tension in Asymptomatic Current Smokers: Assessment with Hyperpolarized³He MR Imaging

Hamedani¹,

Kadlecek²,

Ishii³

et al. 2015

Radiology

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q RSNA, 2014 Purpose:To assess the ability of helium 3 ( 3 He) magnetic resonance (MR) imaging of regional alveolar partial pressure of oxygen (Pao 2 ) to depict smoking-induced functional alterations and to compare its efficacy to that of current diagnostic techniques. Materials andMethods:This study was approved by the local institutional review board and was compliant with HIPAA. All subjects provided informed consent. A total of 43 subjects were separated into three groups: nonsmokers, asymptomatic smokers, and symptomatic smokers. All subjects underwent a Pao 2 imaging session followed by clinically standard pulmonary function tests (PFTs), the 6-minute walk test, and St George Respiratory Questionnaire (SGRQ). The whole-lung mean and standard deviation of Pao 2 were compared with metrics derived from PFTs, the 6-minute walk test, and the SGRQ. A logistic regression model was developed to identify the predictors of alterations to the lungs of asymptomatic smokers. Results:The whole-lung standard deviation of Pao 2 correlated with PFT metrics (forced expiratory volume in 1 second [FEV 1 ]/forced vital capacity [FVC], Pearson r = 20.69, P , .001; percentage predicted FEV 1 , Pearson r = 20.67, P , .001; diffusing capacity of lung for carbon monoxide [Dlco], Pearson r = 20.45, P = .003), SGRQ score (Pearson r = 0.67, P , .001), and distance walked in 6 minutes (Pearson r = 20.47, P = .002). The standard deviation of Pao 2 was significantly higher in asymptomatic smokers than in nonsmokers (change in the standard deviation of Pao 2 = 7.59 mm Hg, P = .041) and lower when compared with symptomatic smokers (change in the standard deviation of Pao 2 = 10.72 mm Hg, P = .001). A multivariate prediction model containing FEV 1 /FVC and the standard deviation of Pao 2 (as significant predictors of subclinical changes in smokers) and Dlco (as a confounding variable) was formulated. This model resulted in an area under the receiver operating characteristic curve with a significant increase of 29.2% when compared with a prediction model based solely on nonimaging clinical tests. Conclusion:The 3 He MR imaging heterogeneity metric (standard deviation of Pao 2 ) enabled the differentiation of all three study cohorts, which indicates that it can depict smoking-related functional alterations in asymptomatic current smokers.q RSNA, 2014 Online supplemental material is available for this article. Note: This copy is for your personal non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights. THORACIC IMAGING: Alterations of Regional Alveolar Oxygen Tension in Asymptomatic SmokersHamedani et al 586 radiology.rsna.org n Radiology: Volume 274: Number 2-February 2015 C hronic obstructive pulmonary disease (COPD) encompasses several pulmonary disorders, including chronic bronchitis and emphysema, and is characterized by altered lung structure and function. The obstruction associated with COPD is likely, at least to some extent, a disruption ...

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Section: Discussionsupporting

confidence: 81%

Alterations of Regional Alveolar Oxygen Tension in Asymptomatic Current Smokers: Assessment with Hyperpolarized³He MR Imaging

Hamedani¹,

Kadlecek²,

Ishii³

et al. 2015

Radiology

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“…of this method revealed significant associations between increased ventilation heterogeneity and smoking, a finding that echoes those from several previous studies (12)(13)(14). It also provided the opportunity to develop several techniques for increasing the accuracy of fractional ventilation measurements.…”

Section: Technical Developments: Regional Fractional Ventilation Meassupporting

confidence: 64%

Regional Fractional Ventilation by Using Multibreath Wash-in³He MR Imaging

Hamedani¹,

Clapp²,

Kadlecek³

et al. 2016

Radiology

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q RSNA, 2016 Purpose:To assess the feasibility and optimize the accuracy of the multibreath wash-in hyperpolarized helium 3 ( 3 He) approach to ventilation measurement by using magnetic resonance (MR) imaging as well as to examine the physiologic differences that this approach reveals among nonsmokers, asymptomatic smokers, and patients with chronic obstructive pulmonary disease (COPD). Materials and Methods:All experiments were approved by the local institutional review board and compliant with HIPAA. Informed consent was obtained from all subjects. To measure fractional ventilation, the authors administered a series of identical normoxic hyperpolarized gas breaths to the subject; after each inspiration, an image was acquired during a short breath hold. Signal intensity buildup was fit to a recursive model that regionally solves for fractional ventilation. This measurement was successfully performed in nine subjects: three healthy nonsmokers (one man, two women; mean age, 45 years 6 4), three asymptomatic smokers (three men; mean age, 51 years 6 5), and three patients with COPD (three men; mean age, 59 years 6 5). Repeated measures analysis of variance was performed, followed by post hoc tests with Bonferroni correction, to assess the differences among the three cohorts. Results: Whole-lung fractional ventilation as measured with hyperpolarized 3He in all subjects (mean, 0.24 6 0.06) showed a strong correlation with global fractional ventilation as measured with a gas delivery device (R 2 = 0.96, P , .001). Significant differences between the means of whole-lung fractional ventilation (F 2,10 = 7.144, P = .012) and fractional ventilation heterogeneity (F 2,10 = 7.639, P = .010) were detected among cohorts. In patients with COPD, the protocol revealed regions wherein fractional ventilation varied substantially over multiple breaths. Conclusion:Multibreath wash-in hyperpolarized 3He MR imaging of fractional ventilation is feasible in human subjects and demonstrates very good global (whole-lung) precision. Fractional ventilation measurement with this physiologically realistic approach reveals significant differences between patients with COPD and healthy subjects. To minimize error, several sources of potential bias must be corrected when calculating fractional ventilation.q RSNA, 2016

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“…An attempt was made to show that decreasing chest expansion correlated with decreasing apical ventilation: however, due to the minimal interpatient variation in chest expansion (range less than 2-5 cm) no such correlation was possible. An alternative explanation for this abnormality is airways obstruction predominantly affecting the apices, as may occur in emphysema (Gaziano et al, 1970). In this case the 'washout' scan, which is a more sensitive indicator of airways obstruction than the inhalation scan (Evans, 1973), should reflect this abnormality.…”

Section: Discussionmentioning

confidence: 99%

“…In other words, high scores reflect less efficient ventilation in contrast to the inhalation and perfusion scans where high scores indicate relatively better function. Detailed accounts of the technique are available in previous publications from this laboratory (Brown, Kirk, and Seaton, 1969;Gaziano, Seaton, and Ogilvie, 1970;Hall, 1974). …”

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confidence: 99%

Regional lung function in ankylosing spondylitis.

Stewart¹,

Ridyard²,

Pearson³

1976

Thorax

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Regional Lung Function in Patients with Obstructive Lung Diseases

Cited by 14 publications

References 14 publications

Alterations of Regional Alveolar Oxygen Tension in Asymptomatic Current Smokers: Assessment with Hyperpolarized³He MR Imaging

Alterations of Regional Alveolar Oxygen Tension in Asymptomatic Current Smokers: Assessment with Hyperpolarized³He MR Imaging

Regional Fractional Ventilation by Using Multibreath Wash-in³He MR Imaging

Regional lung function in ankylosing spondylitis.

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Regional Lung Function in Patients with Obstructive Lung Diseases

Cited by 14 publications

References 14 publications

Alterations of Regional Alveolar Oxygen Tension in Asymptomatic Current Smokers: Assessment with Hyperpolarized3He MR Imaging

Alterations of Regional Alveolar Oxygen Tension in Asymptomatic Current Smokers: Assessment with Hyperpolarized3He MR Imaging

Regional Fractional Ventilation by Using Multibreath Wash-in3He MR Imaging

Regional lung function in ankylosing spondylitis.

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Product

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Alterations of Regional Alveolar Oxygen Tension in Asymptomatic Current Smokers: Assessment with Hyperpolarized³He MR Imaging

Alterations of Regional Alveolar Oxygen Tension in Asymptomatic Current Smokers: Assessment with Hyperpolarized³He MR Imaging

Regional Fractional Ventilation by Using Multibreath Wash-in³He MR Imaging