Incidence and Clinical Impact of Focal Pituitary Uptake in 18F-Fluorodeoxyglucose Positron-emission Tomography–Computed Tomography: 5-Year Retrospective Review
KK Wu, BT Kung, TK Au Yong
Hong Kong J Radiol 2018;21:48-53
DOI: 10.12809/hkjr1616832
Objectives: To identify the incidence and clinical significance of incidental pituitary uptake in whole-body positron-emission tomography–computed tomography using 18F-fluoro-2-deoxy-d-glucose (18F-FDG PET-CT) in Hong Kong.
Methods: We retrospectively reviewed 14,438 records from patients for whom 18F-FDG PET-CT was performed at a public general hospital from 1 September 2007 to 31 August 2012. Patients with known pituitary pathology were excluded. The final diagnosis was based on brain magnetic resonance imaging (MRI) and enhanced CT with or without hormonal assay. Patients with or without an identified pituitary lesion were assigned to the incidentaloma group or the physiological group, respectively. Non-parametric statistical testing and receiver operating characteristic curve analysis were performed to examine data from the two groups. An optimal cut-off maximum standardised uptake value (SUVmax) value was determined to differentiate physiological uptake from other causes.
Results: Incidental pituitary uptake was identified in 55 of 14,438 cases (incidence, 0.38%). After MRI or enhanced CT was performed in 25 of 55 cases, 11 were assigned to the incidentaloma group and the remaining 14 as the physiological group. There was a generally higher SUVmax value in the incidentaloma group (median, 7.30; range, 4.50-17.30) than in the physiological group (median, 3.45; range, 2.60-5.80). The optimal diagnostic cut-off value to discriminate between the two groups was an SUVmax of 4.30 (sensitivity = 100%; specificity = 92.9%; area under the curve = 0.987).
Conclusions: Incidental pituitary uptake is a rare finding in 18F-FDG PET-CT. A high SUVmax value is associated with an increased probability of pituitary incidentaloma and indicates that further imaging and hormonal evaluation are warranted.
中文摘要
18F-FDG PET-CT 檢查出現垂體局部攝取的發生率及其臨床意義：五年追溯性回顧
胡君傑、龔本霆、歐陽定勤
目的：探討18F-FDG PET-CT全身檢查診斷偶發垂體攝取的發生率及其臨床意義。
方法：回顧分析2007年9月1日至2012年8月31日期間在香港一所公立醫院的14,438例18F-FDG PET-CT檢查報告，並排除已知垂體有病理改變的受試者。最後診斷基於腦MRI和增強CT或者結合激素 評估。出現垂體病灶的受試者納入偶發瘤組，沒有病灶的則納入生理學組。兩組數據以非參數測試 和ROC曲線分析，並確定最佳SUVmax閾值（即病灶最大標準化攝取值）以區別生理攝取與其他原 因。
結果：在14,438例中有55例偶發垂體攝取（發生率0.38%）。55名受試者中有25名進行MRI或增 強CT檢查，當中11名被納入偶發瘤組，其餘14名在生理學組。偶發瘤組的SUVmax閾值（中位數 7.30，範圍4.50-17.30）較生理學組高（中位數3.45，範圍2.60-5.80）。區分兩組的最佳診斷截止值 （SUVmax閾值）為4.30（靈敏度100%、特異性92.9%、ROC曲線下面積0.987）。
結論：經18F-FDG PET-CT檢查發現偶發垂體攝取屬罕見。高SUVmax閾值增加垂體偶發瘤的可能 性，所以進一步影像學檢查和激素評估是必要的。