Pre-operative localization of parathyroid tumours using static b scan ultrasonography

Time consuming, inaccurate and often invasive localization procedures before initial surgery in primary hyperparathyroidism are probably not justified. The clinical value of pulsed ultrasound has been appreciated since 1975 and the application of dedicated, high resolution, real time systems is now advocated. This paper examines the efficacy of conventional static B scan equipment in pre-operative localization of parathyroid tumours in 34 patients. When considering all glands, a true positive value (sensitivity) of 55.5 per cent was achieved, with a true negative rate (specificity) of 96.0 per cent. The accuracy for all glands (the true positive plus true negative results as a percentage of all glands scanned) was 85.3 per cent. An accuracy of 93 per cent was achieved when considering glands greater than 5 mm diameter, with false positive and negative rates of 3.6 and 20.0 per cent respectively. The limitations of the the technique are discussed in the context of the current literature.