Investigation of choice for parathyroid pathology is

Tc99m sestamibi (2-methoxy-2-methylpropylisonitrile (MIBI)) is now regarded as the most accurate and reliable method for imaging the parathyroid glands. It is safe and reproducible and while it has a sensitivity and specificity similar to ultrasound, it may image glands in ectopic positions betterThe sensitivity and specificity of sestamibi, are 79% and 90%, respectively. False positives are rare but may arise from some solid thyroid nodules, such as Huhle cell nodules, that are associated with high oxyphilic content. These can be reduced by the addition of a thyroid-specific radioactive tracer, such as 99Tc-peechnetate and subsequent subtraction images(Ref: Grainger&;s diagnostic radiology, 6th ed; page 134)