Pattison David A, Westcott James, Lichtenstein Meir, Toh H B, Gunawardana Dishan, Better Nathan, Forehan Simon, Sivaratnam Dinesh
Departments of aNuclear Medicine bEndocrinology cCardiology, Royal Melbourne Hospital, Parkville dCabrini Private Hospital, Malvern, Victoria, Australia.
Nucl Med Commun. 2015 Apr;36(4):356-62. doi: 10.1097/MNM.0000000000000260.
Amiodarone-induced thyrotoxicosis (AIT) is caused by excessive hormone synthesis and release (AIT I), a destructive thyroiditis (AIT II), or a combination of both (AIT Ind). Although no gold-standard diagnostic test is available, technetium-99m sestamibi thyroid scintigraphy (99mTc-STS) has been previously reported to be an accurate tool for differentiating subtypes with important therapeutic implications. However, the information to guide reporting of 99mTc-STS is qualitative and highly subjective. This study aims to compare the interobserver reliability of 99mTc-STS before and after the use of quantitative thyroid-to-background ratios (TBRs) displayed on a time-activity curve for differentiation of AIT subtypes.
A retrospective audit of Nuclear Medicine Departments at Royal Melbourne Hospital (Parkville, Victoria, Australia) and Cabrini Hospital (Malvern, Victoria, Australia) identified 15 consecutive 99mTc-STS studies performed for AIT. Four nuclear medicine physicians reported the studies according to previously established criteria (series 1). Quantitative TBR and estimated 'normal' range TBR were subsequently provided before the studies were reordered and reported again (series 2). Interobserver reliability was calculated using Fleiss' κ statistic for each assessment.
The overall percentage of agreement (PoA) and κ statistics for use of conventional 99mTc-STS for diagnosis of AIT improved from 47 to 80% and from 0.30 to 0.67 following the use of quantitative TBR displayed on a time-activity curve with reference to a normal population. Interobserver reliability improved substantially under all diagnostic comparisons, particularly for differentiation of either AIT I (PoA 80% to 94%, κ: 0.48 to 0.84) or AIT Ind (PoA 47% to 82%, κ: -0.05 to 0.51) from other types of AIT.
Use of quantitative TBR improves the interobserver reliability of reporting 99mTc-STS for investigation of different types of AIT. There is 'almost perfect' agreement upon differentiation of AIT I from AIT II and AIT Ind, with important implications for rationalizing the use of corticosteroid therapy. Prospective identification of AIT Ind is improved from 'poor' to a 'moderate' level of agreement to facilitate rational use of combination therapy at diagnosis.
胺碘酮所致甲状腺毒症（AIT）由甲状腺激素过度合成与释放（AIT I型）、破坏性甲状腺炎（AIT II型）或两者共同作用（AIT混合型）引起。尽管尚无金标准诊断试验，但此前有报道称，锝-99m甲氧基异丁基异腈甲状腺闪烁扫描（99mTc-STS）是区分亚型的准确工具，对治疗具有重要指导意义。然而，用于指导99mTc-STS报告的信息是定性的且主观性很强。本研究旨在比较使用时间-活性曲线上显示的定量甲状腺与本底比值（TBR）来区分AIT亚型前后，观察者间对99mTc-STS的可靠性。
对澳大利亚维多利亚州帕克维尔皇家墨尔本医院和维多利亚州莫尔文卡布里尼医院核医学科进行回顾性审查，确定了连续15例因AIT进行的99mTc-STS检查。4名核医学医师根据先前制定的标准报告这些检查（系列1）。随后，在重新安排检查并再次报告之前，提供定量TBR和估计的“正常”范围TBR（系列2）。使用Fleiss'κ统计量计算每次评估的观察者间可靠性。
参照正常人群，使用时间-活性曲线上显示的定量TBR后，传统99mTc-STS用于诊断AIT的总体一致率（PoA）和κ统计量分别从47%提高到80%，从0.30提高到0.67。在所有诊断比较中，观察者间可靠性均有显著提高，尤其是在区分AIT I型（PoA从80%提高到94%，κ：从0.48提高到0.84）或AIT混合型（PoA从47%提高到82%，κ：从-0.05提高到0.51）与其他类型AIT时。
使用定量TBR可提高观察者间对99mTc-STS报告的可靠性，用于不同类型AIT的检查。在区分AIT I型与AIT II型及AIT混合型方面存在“几乎完美”的一致性，这对合理使用皮质类固醇治疗具有重要意义。AIT混合型的前瞻性识别从“差”的一致性水平提高到“中等”水平，有助于在诊断时合理使用联合治疗。
