Never say never: Identification of acute pulmonary embolism on non-contrast computed tomography imaging.

Acute undifferentiated illness remains a critical challenge for the emergency physician. The diagnostic evaluation and treatment decisions on such severely ill patients often needs to be made in an expedited fashion. Situations occur wherein the ideal or recommended workup is not always feasible due to time or patient specific factors. We present two cases of patients with undifferentiated acute illness who had undergone non-contrast CT (computed tomography) scanning and subsequently had central pulmonary embolism identified upon careful review of their CT studies.