Although early detection of infarct sign can provide early treatment to patients, early infarct detection on brain images is well-known to be difficult due to their subtle signs. A method is proposed to aid the detection of infarct through image colourisation based on Hounsfield units. A test was conducted in a private university to evaluate the algorithm, and the method appeared helpful and robust. The limited results showed that students with and without medical background had improved their ability of detecting early sign by 5.5% with the help of image colourisation.