11C-methionine PET/CT in 99mTc-sestamibi-negative hyperparathyroidism in patients with renal failure on chronic haemodialysis

Purpose Scintigraphic localisation of parathyroid glands is often unsuccessful in patients with renal failure on chronic haemodialysis who have secondary hyperparathyroidism (HPT). The purpose of this study was to investigate the use of ¹¹C-methionine PET/CT to detect hyperfunctioning parathyroid glands in patients with renal failure on chronic haemodialysis who had ^99mTc-sestamibi-negative HPT. Methods ¹¹C-methionine PET/CT was performed in 18 patients (11 women and 7 men, aged 42–79 years; mean age 57.8 years) on haemodialysis for renal failure (2–14 years’ duration), with normo-, hypo- or hypercalcaemia and HPT not localised by either dual-tracer ^99mTc-pertechnetate/^99mTc-sestamibi subtraction scans or dual-phase ^99mTc-sestamibi scans. Results In three of ten patients with normo- or hypocalcaemic HPT there was increased ¹¹C-methionine accumulation in one gland. Seven of eight patients with hypercalcaemic HPT showed increased uptake: in five of these patients increased ¹¹C-methionine accumulation was present in one gland, while in two it was demonstrated in two glands. All patients also had high-resolution ultrasound of the neck and were treated with subtotal parathyroidectomy, leaving a remnant of the smallest of the four glands. Regardless of their size, all glands with abnormal ¹¹C-methionine parathyroid uptake were removed, and all demonstrated parathyroid hyperplasia. All patients developed post-parathyroidectomy hypoparathyroidism and one patient with normocalcaemic HPT relapsed 8 months after surgery. Conclusion These data suggest that ¹¹C-methionine PET/CT may be used to identify hyperfunctioning parathyroid glands in non-primary HPT, and especially hypercalcaemic HPT, when conventional ^99mTc-sestamibi imaging is non-localising.