Use of ventilation-perfusion (V/Q) scan to diagnose PE is a well established practice. However performing the ventilation part of the scan is technicaly demanding and associated with significant degree of radiation exposure for both the technician and the patient. We conducted a retrospective study to compare the diagnostic abilities of perfusion lung scan and ventilation-perfusion (V/Q) scan for detecting pulmonary emboli.
We reviewed the charts of all 283 patients who underwent nuclear lung imaging studies in 2004. Of these 283 patients, 46 had both nuclear lung imaging and pulmonary CT angiogram within 48 hours of each other. Of these 46 patients, 16 had both ventilation and perfusion nuclear scan done and the remaining 30 had only perfusion scan done. We compared the sensitivity and specificity of nuclear lung imaging for both groups. We used pulmonary CT angiogram as a reference test for diagnosis of pulmonary embolism.
There were 20 males and 26 females with age range: 18-88 years, and mean age 53.6 years. For the group of patients who had ventilation-perfusion (V/Q) scan done the sensitivity was 100% and the specificity 92%. For the group of patients who had only perfusion scan done the sensitivity was 100%, and the specificity was 80%.
Compared to perfusion scan alone ventilation-perfusion (V/Q) scan has similar sensitivity, but higher specificity for detecting PE.
Even though technically challenging and associated with higher degree of exposure to radiation performing ventilation scan along with perfusion scan will increase the diagnostic accuracy of nuclear lung imaging in the diagnosis of PE.
G. Gandev, None.