Fig. 25.11 Imaging of a parathyroid adenoma. Image (a) shows a pertechnetate thyroid scan obtained conventionally 10ΓÇô20 minutes after the intravenous injection of 99mTc pertechnetate through an indwelling needle. Without the patient moving, 99mTc methoxyisobutylisonitnle (MIBI) is injected and a further series of images taken. In (b) 99mTc MIBI is taken up both by the parathyroid adenoma and by normal thyroid so that a combined composite image is seen. Using a change detection algorithm, the change between the two images is determined and the statistical degree of that difference is plotted as a probability. In (c) the high red and orange in the upper pole of the left lobe of the thyroid indicates a change between the two images with a significance of over one in a thousand. This is the site of the upper pole parathyroid adenoma. The outline of the thyroid is also shown. A small area of increased probability of change is also seen in the upper pole of the right lobe of the thyroid.
