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

• Published in: Annals of nuclear medicine Vol. 29; no. 1; pp. 91 - 99
• Main Authors: Bajc, Marika, Markstad, Hanna, Jarenbäck, Linnea, Tufvesson, Ellen, Bjermer, Leif, Jögi, Jonas
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.01.2015; Springer Nature B.V
• Subjects: Aged; Airway Obstruction - diagnostic imaging; Airway Obstruction - physiopathology; Cardiac and Cardiovascular Systems; Clinical Medicine; Female; Humans; Imaging; Kardiologi; Klinisk medicin; Lung - diagnostic imaging; Lung - physiopathology; Lungmedicin och allergi; Male; Medical and Health Sciences; Medicin och hälsovetenskap; Medicine; Medicine & Public Health; Middle Aged; Nuclear Medicine; Original; Original Article; Prospective Studies; Pulmonary Disease, Chronic Obstructive - diagnostic imaging; Pulmonary Disease, Chronic Obstructive - physiopathology; Radiology; Respiratory Medicine and Allergy; Severity of Illness Index; Smoking - pathology; Smoking - physiopathology; Spirometry; Surveys and Questionnaires; Tomography, Emission-Computed, Single-Photon - methods; Chronic obstructive pulmonary disease (COPD); Imaging interpretation criteria; Pulmonary scintigraphy; Ventilation/Perfusion SPECT; Technegas
• DOI: 10.1007/s12149-014-0913-y
• ISSN: 0914-7187; 1864-6433

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. Purpose To define and validate criteria to stage COPD using V/P SPECT. Method 74 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. Results Obstructivity-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). Conclusion Functional 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.