[Preoperative instrumental diagnosis in secondary hyperparathyroidism].

There is a very high incidence of hyperparathyroidism secondary to chronic renal insufficiency in dialysed patients (67%). When medical therapy can no longer control the evolution of disease, an appropriate surgical strategy must be defined for the clinical case. Instrumental tests play an important role during the preoperative phase in the possible "localisation" of ectopic parathyroids (10% of cases) and the identification of those glands with a more pronounced hyperplastic appearance. The authors examine and describe the most useful tests for a preoperative study, namely ultrasonography, echo-colour Doppler, scintigraphy using a dual tracer and image subtraction, computerised xial tomography (CT), magnetic resonance (MR), digital angiography and intraoperative ultrasonography. In conclusion, it can be said that all the methods examined present similar sensitivity levels for the study of parathyroid, but the combination of more than one technique considerably improves diagnostic accuracy.