State-of-the-Art Imaging for the Evaluation of Pulmonary Embolism.

PURPOSE OF REVIEW: CT angiography has become the gold standard for evaluation of suspected pulmonary embolism; however, continuous evolution in radiology has led to new imaging approaches that offer improved options for detection and characterization of pulmonary embolism while exposing patients to lower contrast and radiation dose. The purpose of this review is to summarize state of the art imaging approaches for the evaluation of pulmonary embolism, focusing on technical innovations in this field. RECENT
FINDINGS: The introduction of dual-energy CT has resulted in the ability to add functional and prognostic information beyond the morphologic assessment of the pulmonary arteries and potentially offer improved image quality without additional radiation burden. New approaches and strategies in CT scanning have resulted in decreased radiation exposure as well as a significant decrease in contrast material used without decreasing the sensitivity for detection of pulmonary embolism. Continuous developments and improvements in MR angiography techniques offer a valuable and efficient option for certain patient populations without the risk of radiation exposure. Improvements in the technical success rate and reliability of this modality will mean more widespread use in the future. Moving beyond planar ventilation/perfusion (V/Q) scintigraphy, nuclear imaging offers several new approaches, including the use of single photon emission computed tomography (SPECT) and SPECT/CT resulting in superior diagnostic performance and a decrease in nondiagnostic studies, potentially surpassing the diagnostic capabilities of computed tomography pulmonary angiography. Ongoing research in the use of V/Q PET/CT demonstrates superior temporal and spatial resolution and quantitative capabilities compared to SPECT-CT; this modality will likely play an increasing role in the detection and characterization of pulmonary embolism. The field of pulmonary embolism imaging has demonstrated continuous evolution in both development of novel techniques and improvement in current technologies, resulting in better detection, decreased radiation exposure, and enhanced functional information beyond morphologic characterization of the pulmonary vasculature.