FRI688 Efficacy Of 4D CT Scan And Tc-99m-MIBI-SPECT/CT For The Preoperative Localization Of Abnormal Parathyroid Glands In Patients With Primary Hyperparathyroidism

Disclosure: E. Zareva: None. V. Rivera-Hernandez: None. S. Salpekar: None. J. Moyo: None. M. Bilbatua: None. Z. Lauer: None. A. Zare: None. P. Kaur: None. M. Deshmukh: None. Background: Primary hyperparathyroidism is a common endocrine disorder that often requires surgical intervention for a cure. Accurate localization of abnormal parathyroid glands is critical for successful surgical treatment. NM Parathyroid scan with single-photon emission computed tomography(Tc99m-MIBI-SPECT/CT) is considered the gold standard, but other options like ultrasound, CT, MRI, and PET have been used. Accurate preoperative imaging has become even more critical with the development of focused surgical approaches. This study aims to evaluate the accuracy of Tc99m-MIBI-SPECT/CT and 4D CT scan in localizing abnormal parathyroid glands in our institution. Objectives: To evaluate and compare the efficacy of 4D CT scan and Tc99m-MIBI-SPECT/CT for the preoperative localization of abnormal parathyroid glands in patients with primary hyperparathyroidism in a single health network. Methods and Design: We collected data on 100 patients with biochemically confirmed primary hyperparathyroidism regarding age, sex, image modalities such asTc99m-MIBI-SPECT/CT and 4D CT before surgery, and the surgical pathology results. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for both imaging modalities. Results: A total of 100 patient charts were reviewed, including 77 females and 23 males (3.35:1 female to male ratio),with an average age of 65.9 years (standard deviation 12.59). 90 patients had undergone surgical resection. 54 (60%) of them were diagnosed as parathyroid adenoma; 30 (33.3%) as parathyroid hyperplasia; 1 (1.1%) malignant parathyroid carcinoma; 5 (5.5%) were normal. 84 patients underwent Tc99m-MIBI-SPECT/CT and97 patients - 4D CT. 4D CT scan had a sensitivity of 90.36% (95% CI,81.89%-95.75%) and specificity of 50.00% (95% CI, 6.76%-93.24%) and outperformed Tc99m-MIBI-SPECT/CT which had a sensitivity of 45.71% (95% CI,33.74%-58.06%) and specificity of 80.00% (95% CI, 28.36%-99.49%). 4D CT had a positive predictive value (PPV) of 97.40% (95% CI, 90.93%-99.68%) and a negative predictive value (NPV) of 20.01% (95% CI, 2.52%-55.62%) compared toTc99m-MIBI-SPECT/CT which had PPV of 96.95% (95% CI, 84.22%-99.92%) and NPV of9.57% (95% CI, 2.68%-22.68%). 4D CT also had higher accuracy (85.5%; 95% CI,79.87%-94.35%) compared to Tc99m-MIBI scan (48.01%; 95% CI,36.32%-59.86%). Conclusion: Diagnostic imaging plays a crucial role in the management of primary hyperparathyroidism. Among the patients who had Tc99m-MIBI-SPECT/CT, less than half had positive scans suggestive of abnormal parathyroid tissue. This highlights the need for additional imaging methods for patients with negative scans. 4D CT is widely used in our institution and is more effective than Tc99m-MIBI-SPECT/CT in the preoperative localization of abnormal parathyroid glands. Presentation: Friday, June 16, 2023