Grading obstructive lung disease using tomographic pulmonary scintigraphy in patients with chronic obstructive pulmonary disease (COPD) and long-term smokers.

Marika Bajc,Leif Bjermer,Hanna Markstad,Ellen Tufvesson,Jonas Jögi,Linnea Jarenbäck

doi:10.1007/s12149-014-0913-y

Abstract

The severity of chronic obstructive lung disease (COPD) is defined by the degree of flow limitation measured as forced expiratory volume in 1 s, which mainly reflects impairment of large and intermediate airways. However, COPD is primarily a small airways disease. Therefore, better diagnostic tools are needed. Ventilation-Perfusion (V/P) SPECT is a sensitive method to detect obstructive lung changes but criteria for staging airway obstruction are missing.PurposeTo define and validate criteria to stage COPD using V/P SPECT.Method74 subjects (healthy non-smokers, healthy smokers or with stable COPD) were included. All were examined with V/P SPECT in a hybrid SPECT/CT system. Spirometry was performed and patients were evaluated with the clinical COPD questionnaire (CCQ). V/P SPECT was interpreted independently. Preserved lung function (%) was evaluated. The degree of airway obstruction on V/P SPECT was graded according to newly-developed grading criteria. The degree of airway obstruction was graded from normal (0) to severe (3). The airway obstructivity-grade and degree of preserved lung function were compared to GOLD, CCQ and LDCT emphysema extent.ResultsObstructivity-grade (r = 0.66, P < 0.001) and the degree of preserved lung function (r = −0.70, P < 0.001) both correlated to GOLD. Total preserved lung function decreased in relation to higher GOLD stage. There was a significant difference between healthy controls and apparently healthy long time smokers both regarding obstructivity-grade (P = 0.001) and preserved lung function (P < 0.001). Long-time smokers did not differ significantly from GOLD 1 COPD patients (P = 0.14 and P = 0.55 for obstructivity-grade and preserved lung function, respectively). However, patients in GOLD 1 differed in obstructivity-grade from non-smoking controls (P = 0.02).ConclusionFunctional imaging with V/P SPECT enables standardized grading of airway obstruction as well as reduced lung function, both of which correlate with GOLD stage. V/P SPECT shows that long-term smokers in most cases have signs of ventilatory impairment and airway obstruction not shown by spirometry.

Highlights

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality
Functional imaging with V/P SPECT enables standardized grading of airway obstruction as well as reduced lung function, both of which correlate with Global initiative for obstructive lung disease (GOLD) stage
V/P SPECT shows that long-term smokers in most cases have signs of ventilatory impairment and airway obstruction not shown by spirometry

Summary

Introduction

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality. COPD is characterized by airflow limitation and abnormal inflammatory response, most often as a result of cigarette smoking [1, 2]. The changes that occur in the lungs include increased airway resistance due to airway fibrosis, inflammation and luminal plugs, and increased compliance caused by parenchymal destruction and loss of alveolar attachments. There are vascular changes due to inflammatory remodelling with. Ann Nucl Med (2015) 29:91–99 progressive vascular occlusion and loss of vasculature in areas with emphysematous destruction. COPD is a heterogeneous condition and the clinical presentation, pathophysiology, disease progression and response to therapy vary between patients [3]. Comorbidities like heart failure, lung cancer, pulmonary vascular disease, pulmonary embolism (PE) and atherosclerosis are common [4, 5]

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