99mTc-MIBI SPECT in primary hyperparathyroidism. Influence of concomitant vitamin D deficiency for visualization of parathyroid adenomas.

UNLABELLED: AIM of the study was to analyse the influence of a concomitant vitamin D deficiency on the results of (99m)Tc-MIBI studies in patients (pts) with primary hyperparathyroidism (pHPT).

PATIENTS,

METHODS

Between January 1998 and May 2004, 71 pts with pHPT had undergone operation after a (99m)Tc-MIBI study of whom 54 pts (76%) had normal values of 25-OH-vitamin D3 and 17 pts (24%) had vitamin D deficiency. Results of a dual-phase (99m)Tc-MIBI protocol with SPECT were compared with histopathology.

RESULTS

In 54 pts with normal vitamin D values late SPECT images identified more lesions (n=51, sensitivity 91%) than early planar (n=45, sensitivity 82%) or late planar images (n=50, sensitivity 88%). In 17 pts with vitamin D deficiency late SPECT images identified more lesions (n=13, sensitivity 72%) than early planar (n=10, sensitivity 56%) or late planar images (n=10, sensitivity 56%) too. In pts with vitamin D deficiency the sensitivity of a (99m)Tc-MIBI SPECT study was lower than in those with normal vitamin D status (72% vs. 91%) and dependent on the value for PTH. However, the results did not reach statistical significance: early planar: p=0.1625; late planar: p=0.0039; (99m)Tc-MIBI SPECT: p=0.1180.

CONCLUSION

The likelihood of a pathological (99m)Tc-MIBI study being obtained in pts with pHPT is dependent on the parathyroid hormone level. However, a negative influence of a low vitamin D level on the scintigraphic detection rate of a parathyroid adenoma could not be proven which may be due to the low number of pts with vitamin D deficiency.