ABSTRACT
Cross-sectional imaging is necessary in the form of Computerized Tomography (CT) and magnetic resonance imaging (MRI). CT remains the mainstay for initial assessment as it is widely available, fast and is very good for assessing soft tissue and bony injury, facilitating any emergent or urgent neurosurgical intervention. Choice of window levels and window widths is key to interpretation as these alter the contrast between tissues. MRI utilises a different principle in image acquisition. Hydrogen, being present in water molecules and hence in all body tissues, behaves like micro-compass with a single proton. Radiofrequency pulses are deployed to disrupt the alignment of these micro-compasses. The time course of a haematoma is not absolute and can vary slightly with individuals, local environment and size of haematoma. MRI signal of blood products is highly complex as blood products evolve, each stage of evolution is reflected in the alteration of signal intensity, which also differs with the different imaging sequences.
