Incidental detection of parathyroid adenomas on chest CT before clinical presentation of hyperparathyroidism.

Rationale and objectives: To evaluate whether parathyroid adenomas can be detected by thoracic radiologists on routine chest CT.

Materials/methods: This retrospective study included patients with hyperparathyroidism evaluated by parathyroid scans and a control group with normal calcium. All had enhanced chest CT within 36 months prior to parathyroid imaging. Chest CTs were reviewed by 3 blinded thoracic radiologists. We report diagnostic accuracy for all positive findings and findings > 8 mm.

Results: Our sample comprised 126 patients, 63 with confirmed hyperparathyroidism and 63 control patients; 6 parathyroid cases were excluded for being out of the field of view. Readers 1, 2, and 3 had sensitivity of 95%, 60%, and 35%, and specificity of 88%, 89%, and 97%, respectively. Specificity increased to 95%, 97%, and 98% when considering only findings larger than 8 mm. Review of false negative studies for reader 1 revealed 3 parathyroid adenomas visualized in retrospect. Review of the 7 false positive studies for reader 1 revealed candidate lesions in all of them attributed to exophytic thyroid nodules or lymph nodes. 90%, 67%, and 40% of the parathyroid adenoma patients had at least 1, 2, and 3 complications respectively. Most prevalent complications were nephrolithiasis (48%) and osteopenia (46%).

Conclusions: Routine contrast-enhanced chest CT can detect the majority of parathyroid adenomas with high specificity.

Clinical relevance/application: Increasing awareness of parathyroid adenomas by chest radiologists allow for detection of enlarged parathyroid glands, diagnosing hyperparathyroidism before clinical presentation.