The Incremental Value of Single-photon Emission Computed Tomography / Computed Tomography in Post-thyroidectomy Iodine-131 Scanning of Differentiated Thyroid Carcinoma. Part I: Retrospective Analysis of 26 Cases
P Tang, K Wang, CY Cheung, SF Leung
Hong Kong J Radiol 2012;15:213-9
Objective: This study investigated whether single-photon emission computed tomography (SPECT) with integrated low-dose computed tomography (CT) may have additional value over whole-body scintigraphy in determining the presence and location of tumour uptake in patients with differentiated thyroid carcinoma.
Methods:Between 1 January and 31 December 2011, planar imaging was performed on 79 patients after total or nearly total thyroidectomy for differentiated thyroid carcinoma. Of these patients, 26 also underwent SPECT/ CT (using an integrated system) because the planar findings were inconclusive. Fusion images were considered to have incremental value over planar images when they better localised sites of increased iodine-131 uptake. The final diagnosis was supplemented by other imaging modalities, serological correlation, and clinical follow-up. The impact of SPECT/CT results on therapeutic strategy was assessed.
Results:SPECT/CT had an incremental value over planar imaging in all of the 26 patients who underwent fusion imaging, by exclusion of distant metastases (42%), differentiation of pathological versus physiological uptake (38%), more accurate localisation of equivocal uptake (50%), discrimination between normal remnants and lymph node metastases in the neck (12%), and identification of occult lesions in the skeleton unsuspected on planar imaging (12%). SPECT/CT led to modified therapeutic management in nine (35%) of the 26 patients studied.
Conclusion: The use of SPECT/CT fusion imaging offered incremental value over whole-body scintigraphy in increasing diagnostic accuracy, improving the interpretation of equivocal uptake, and modifying therapeutic strategies.
中文摘要
分化型甲狀腺癌患者甲狀腺切除術後使用SPECT/CT 掃描偵測放射性碘 （I-131）的優勢：第一部份：26個病例回顧分析
鄧蕙碧、王琪、張智欣、梁承暉
目的：探討為分化型甲狀腺癌患者檢測腫瘤性濃聚灶的存在及其位置時，單光子發射電腦斷層攝影 （SPECT）配合低劑量電腦斷層攝影（CT）是否比全身顯像更有優勢。
方法：2011年1月1日至12月31日期間，接受甲狀腺全切除或近全切除的79名分化型甲狀腺癌患者進 行平面顯像。其中26人因其平面顯像結果屬非結論性，所以亦透過一個集成系統接受SPECT/CT掃 描。如果融合圖像對I-131濃聚灶定位更佳，便顯示SPECT/CT掃描相對平面顯像較有優勢。然後輔以 其他影像學檢查、相關的血清學、和臨床隨訪來作最終診斷。同時評估SPECT/CT掃描結果對於治療 策略的影響。
結果：26名病人的結果顯示其SPECT/CT融合圖像比平面顯像更有優勢，因融合圖像有助排除遠處轉 移腫瘤的可能性（42%）、能區分病理性濃聚及生理性濃聚（38%）、對可疑濃聚灶有更準確的定位 （50%）、能分辨頸部術後殘留的正常淋巴結與轉移淋巴結（12%），以及能夠識別平面顯像漏診的 骨組織隱匿病灶（12%）。26名病人中，9人（35%）的SPECT/CT掃描結果改變了醫生的治療策略。
結論：與全身顯像比較，SPECT/CT融合圖像較有優勢，這技術增加了診斷的準確性，改善了對可疑 濃聚灶的解釋，及改變了治療策略。