A Comparison of Single-Photon Emission CT Lung Scintigraphy and CT Pulmonary Angiography for the Diagnosis of Pulmonary Embolism

Background: This study compared single-photon emission CT (SPECT) ventilation/perfusion ((V) over dot/(Q) over dot) scintigraphy with multislice CT pulmonary angiography (CTPA). Methods: In a prospective, observational study, 100 patients who were >= 50 years of age were recruited. Seventy-nine patients underwent both diagnostic 16-detector CTPA, and planar and SPECT (V) over dot/(Q) over dot scintigraphy. The agreement between the CTPA and the SPECT (V) over dot/(Q) over dot scintigraphy for the diagnosis of pulmonary embolism (PE) was calculated. The sensitivity and specificity of blinded SPECT scintigraphy reporting was calculated against a reference diagnosis made by a panel of respiratory physicians that was provided with CTPA and planar (V) over dot/(Q) over dot scintigraphy reports, clinical information, and 3-month follow-up data. Results: The observed percentage of agreement between SPECT (V) over dot/(Q) over dot scintigraphy and CTPA data for the diagnosis of PE was 95%. When calculated against the respiratory physicians' reference diagnosis, SPECT (V) over dot/(Q) over dot scintigraphy had a sensitivity of 83% and a specificity of 98%. Conclusions: This study indicates that SPECT (V) over dot/(Q) over dot scintigraphy is a viable alternative to CTPA for the diagnosis of PE and has potential advantages in that it was feasible in more patients and had fewer contraindications; lower radiation dose; and, arguably, fewer nondiagnostic findings than CTPA. Trial registration: Australian New Zealand Clinical Trials Registry Registration Number: ACTRN12609000089235 (CHEST 2009; 136:1546-1553)