title: The added value of hybrid ventilation/perfusion SPECT/CT in patients with stable COPD or apparently healthy smokers. Cancer-suspected CT findings in the lungs are common when hybrid imaging is used.
abstract: Ventilation/perfusion (V/P) single-photon emission computed tomography (SPECT) is recognized as a diagnostic method with potential beyond the diagnosis of pulmonary embolism. V/P SPECT identifies functional impairment in diseases such as heart failure (HF), pneumonia, and chronic obstructive pulmonary disease (COPD). The development of hybrid SPECT/computed tomography (CT) systems, combining functional with morphological imaging through the addition of low-dose CT (LDCT), may be useful in COPD, as these patients are prone to lung cancer and other comorbidities. The aim of this study was to investigate the added value of LDCT among healthy smokers and patients with stable COPD, when examined with V/P SPECT/CT hybrid imaging. Sixty-nine subjects, 55 with COPD (GOLD I-IV) and 14 apparently healthy smokers, were examined with V/P SPECT and LDCT hybrid imaging. Spirometry was used to verify COPD grade. Only one apparently healthy smoker and three COPD patients had a normal or nearly normal V/P SPECT. All other patients showed various degrees of airway obstruction, even when spirometry was normal. The same interpretation was reached on both modalities in 39% of the patients. LDCT made V/P SPECT interpretation more certain in 9% of the patients and, in 52%, LDCT provided additional diagnoses. LDCT better characterized the type of emphysema in 12 patients. In 19 cases, tumor-suspected changes were reported. Three of these 19 patients (ie, 4.3% of all subjects) were in the end confirmed to have lung cancer. The majority of LDCT findings were not regarded as clinically significant. V/P SPECT identified perfusion patterns consistent with decompensated left ventricular HF in 14 COPD patients. In 16 patients (23%), perfusion defects were observed. HF and perfusion defects were not recognized with LDCT. In COPD patients and long-time smokers, hybrid imaging had added value compared to V/P SPECT alone, by identifying patients with lung malignancy and more clearly identifying emphysema. V/P SPECT visualizes comorbidities to COPD not seen with LDCT, such as pulmonary embolism and left ventricular HF.
authors.affiliation: Department of Clinical Physiology and Nuclear Medicine, Skåne University Hospital and Lund University, Lund, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Jögi
authors.affiliation: Department of Radiology, Skåne University Hospital and Lund University, Lund, Sweden.
authors.forename: Hanna
authors.initials: H
authors.lastname: Markstad
authors.affiliation: Department of Respiratory Medicine and Allergology, Skåne University Hospital and Lund University, Lund, Sweden.
authors.forename: Ellen
authors.initials: E
authors.lastname: Tufvesson
authors.affiliation: Department of Respiratory Medicine and Allergology, Skåne University Hospital and Lund University, Lund, Sweden.
authors.forename: Leif
authors.initials: L
authors.lastname: Bjermer
authors.affiliation: Department of Clinical Physiology and Nuclear Medicine, Skåne University Hospital and Lund University, Lund, Sweden.
authors.forename: Marika
authors.initials: M
authors.lastname: Bajc
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D015897:Comorbidity; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000453:epidemiology; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D055420:Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging / Q000453:epidemiology; D011656:Pulmonary Emphysema / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D013548:Sweden / Q000453:epidemiology; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
keywords: V/P SPECT; computed tomography; lung; lung cancer; single-photon emission computed tomography; ventilation/perfusion