Diagnosis of posttraumatic pulmonary embolism: is chest computed tomographic angiography acceptable?
PE frequently occurs soon after injury. The majority of PEs after trauma are found peripherally (in segmental or subsegmental vessels). Right/left pulmonary artery embolisms are likely to be found only later in a trauma patient's course. Any diagnostic study used to diagnose pulmonary embolism in trauma patients must have sufficient resolution capacity to reliably detect segmental and subsegmental clot. A diagnostic modality such as CT scanning that is insensitive to peripheral embolisms may miss a significant number of posttraumatic PEs.
In approximately half of cases the diagnosis of colorectal cancer is not associated with anaemia. Anaemia is more common with proximal lesions but this is not a consistent finding. The current threshold for anaemia at which national guidelines suggest referral also appears to be insensitive.