Added Value of Low-Dose CT by using SPECT V/Q Scan in the Diagnosis of Pulmonary Embolism

Untreated Pulmonary Embolism (PE) can be lethal, with fatality rates ranging from 10% to 30%. Although a variety of symptoms, signs, laboratory tests and/or predisposing patient characteristics can be utilized to develop a clinical probability of PE, these criteria are frequently vague making PE diagnosis difficult even in a strongly suspected case. PE is diagnosed based on clinical symptoms, D-dimer test findings and imaging investigations such as Multi Detector CT (MDCT) and Ventilation/perfusion (V/Q) scintigraphy. So far, radionuclide imaging has only used planar and Single Photon Emission CT (SPECT) methods. Although both methods provide information on radioisotope distribution, neither provides anatomical detail. Furthermore, perfusion and breathing investigations are necessary to confirm or rule out the diagnosis of PE.