Double-phase parathyroid scintigraphy in dogs using technetium-99M-sestamibi

Area of Science:

• Veterinary medicine
• Nuclear medicine
• Endocrinology

Background:

• Hypercalcemia in dogs can be caused by hyperfunctioning parathyroid glands.
• Accurate diagnosis and localization of abnormal parathyroid tissue are crucial for effective treatment.

Purpose of the Study:

• To evaluate the diagnostic utility of double-phase parathyroid scintigraphy using 99mTc-sestamibi in hypercalcemic dogs.
• To determine the sensitivity, specificity, and accuracy of this imaging modality for detecting and localizing hyperfunctioning parathyroid glands.

Main Methods:

• Retrospective analysis of 15 hypercalcemic dogs that underwent 99mTc-sestamibi parathyroid scintigraphy.
• Histopathologic examination confirmed the presence of parathyroid adenoma or hyperplasia in 12 dogs.
• Scintigraphy results were compared with histopathologic findings and clinical data.

Main Results:

• Overall sensitivity was 11%, specificity 50%, and accuracy 27%.
• Scintigraphy correctly identified hyperfunctioning tissue in only 1 of 6 dogs with parathyroid adenoma (25% sensitivity).
• Scintigraphy failed to detect hyperplastic glands in 5 of 6 dogs (0% sensitivity) and yielded false positives in one case.

Conclusions:

• Double-phase parathyroid scintigraphy demonstrates low diagnostic accuracy for detecting and localizing hyperfunctioning parathyroid glands in dogs.
• The poor sensitivity and specificity render this technique unreliable for definitive diagnosis of the cause of hypercalcemia in canine patients.
• Parathyroid scintigraphy is not recommended for routine use in identifying abnormal parathyroid glands in hypercalcemic dogs.