Imaging of hyperparathyroidism: US, CT, MRI and MIBI scintigraphy.

Hyperparathyroidism is a rare condition although recently the incidence has increased, particularly the asymptomatic form, as a result of routine serum calcium measurements. A definitive diagnosis can be made using modern bio-assays giving direct measurements of parathormone (PTH). Various methods are currently available for pre-operative localisation of pathological parathyroid glands. Ultrasound is sufficient prior to the initial surgery. However, if primary surgical exploration fails to localise the parathyroid glands then the surgeon faces a more complex problem and requires precise localisation prior to repeat surgery to reduce operating time and risk. No radiological method is available to localise pathological glands in 100% of cases. The surgeon is usually satisfied when two different methods are positive and in concordance. The non-invasive methods such as ultrasound, CT, MRI and scintigraphy are initially performed and if the result remains equivocal then more invasive methods such as arterial or venous sampling are undertaken. Our preliminary results in secondary hyperparathyroidism, before repeat surgery, indicate that associated and complementary tests, morphological and functional, MRI (fat-sat, T1, gadolinium) and MIBI scintigraphy, have greater efficacy.