State-of-the-Art Imaging in Pulmonary Embolism: Ventilation/Perfusion Single-Photon Emission Computed Tomography versus Computed Tomography Angiography - Controversies, Results, and Recommendations from a Systematic Review.

Pulmonary embolism (PE) is a common, ubiquitous, and potentially lethal disease. As symptoms and clinical findings are notoriously nonspecific, diagnostic imaging is essential to avoid undertreatment as well as overtreatment. Controversies remain regarding first-line imaging in suspected PE. The two main contemporary contenders are ventilation/perfusion scintigraphy with single-photon emission computed tomography (V/Q SPECT) with or without additional low-dose CT (SPECT/CT) and CT angiography (CTA). We present our results from a systematic review and meta-analysis of the diagnostic performances of these modalities: V/Q SPECT, V/Q SPECT/CT, and CTA are all viable options, but we consider V/Q SPECT/CT to be superior in most clinical settings with better overall diagnostic performance, that is, pooled sensitivities (97.6 vs. 82.0%), specificities (95.9 vs. 94.9%), positive predictive values (93.0 vs. 93.8%), negative predictive values (98.6 vs. 84.7%), and accuracies (96.5 vs. 88.6%). We further address some of the ongoing controversies regarding the various modalities, that is, radiation exposure, the issues of subsegmental PE, nondiagnostic studies, and various challenges in specific patient populations.