Computed tomography (CT) is a medical imaging technique that uses X-rays and a computer to produce detailed cross-sectional images of the body’s internal structures. Unlike a conventional X-ray, which produces a flat two-dimensional image, CT captures multiple X-ray measurements from different angles as the scanner rotates around the patient, and the computer reconstructs these into detailed three-dimensional images that can be viewed in any plane.
In cardiac and emergency medicine, CT is used extensively in contexts relevant to cardiac arrest and cardiovascular disease. CT pulmonary angiography (CTPA) is the gold standard investigation for pulmonary embolism, a reversible cause of cardiac arrest. CT aortic angiography rapidly diagnoses aortic dissection. CT coronary angiography (CTCA) is a non-invasive method for assessing coronary artery disease. CT brain scanning is essential in post-arrest management to detect or exclude subarachnoid haemorrhage, cerebral haemorrhage, and hypoxic-ischaemic brain injury.
CT scans are fast (typically seconds to a few minutes), widely available, and provide high spatial resolution images. They are essential in emergencies where rapid diagnosis is required. The main considerations are exposure to ionising radiation and, for CT angiography, the use of intravenous contrast dye, which can occasionally cause allergic reactions or affect kidney function. Patient safety protocols ensure that CT is used when the clinical benefit outweighs these small risks.
After cardiac arrest, CT imaging is frequently performed as part of the post-resuscitation diagnostic workup, particularly to exclude or confirm a coronary artery cause, detect pulmonary embolism, or assess brain injury.
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