Xu Xiao-jun, Lou Fen-lan, Zhang Min-ming, Pan Zhi-mei
Department of Diagnostic Radiology, First Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China.
Zhonghua Zhong Liu Za Zhi. 2006 May;28(5):377-80.
The purpose of this study is to investigate whether low-dose spiral chest CT scan can replace standard-dose CT scan in detecting pulmonary metastases for patients with gestational trophoblastic tumor (GTT).
Totally, 34 GTT patients underwent 56 chest CT scans for the assessment of pulmonary metastasis. All patients received CT examination both at standard-dose (120 KV, 150 mAs, pitch 1, and a standard reconstruction algorithm) and low-dose CT (120 KV, 40 mAs, pitch 2, and a bone reconstruction algorithm) simultaneously each time. The images were interpreted by two radiologists independently. A metastasis by CT image was defined as a nodule within lung parenchyma that could not be attributed to a pulmonary vessel. The number of lesions detected at each dose protocol was recorded. The size of each lesion was measured and categorized as < 5 mm, 5 - 10 mm or > or = 10 mm. The differences in detection of the lesions between the standard- and low-dose CT protocols were compared using Wilconxon signed rank test.
1417 lesions were detected at the standard-dose, whereas 1214 lesions were found by low-dose CT. Lesions < 5 mm detected by low-dose CT were fewer than that detected by standard-dose CT (Z = -3.368, P = 0.000), though there was no statistically significant difference between the standard- and low-dose CT in detecting lesion > or = 5 mm (Z = -0.055, P = 0.957). Moreover, the risk score of the patients was not affected either. The sensitivity of low-dose CT was 69.16% for all size of lesions, 58.50% for < 5 mm, 87.07% for 5 - 10 mm, and 97.01% for > or = 10 mm. The positive predictive value for different sizes of lesion was 80.71% (all sizes), 73.82% (5 mm), 88.86% (5 - 10 mm), and 98.48% (> or = 10 mm), respectively.
Low-dose chest CT can replace the standard-dose chest CT as a screening and follow-up examination to assess the change in pulmonary metastasis for patients with gestational trophoblastic tumor.
本研究旨在探讨低剂量螺旋胸部CT扫描在检测妊娠滋养细胞肿瘤（GTT）患者肺转移方面是否能替代标准剂量CT扫描。
共有34例GTT患者接受了56次胸部CT扫描以评估肺转移情况。所有患者每次均同时接受标准剂量（120千伏，150毫安秒，螺距1，采用标准重建算法）和低剂量CT（120千伏，40毫安秒，螺距2，采用骨重建算法）检查。图像由两名放射科医生独立解读。CT图像上的转移灶定义为肺实质内不能归因于肺血管的结节。记录每个剂量方案下检测到的病灶数量。测量每个病灶的大小并分类为<5毫米、5 - 10毫米或≥10毫米。使用Wilconxon符号秩检验比较标准剂量和低剂量CT方案在病灶检测上的差异。
标准剂量下检测到1417个病灶，而低剂量CT检测到1214个病灶。低剂量CT检测到的<5毫米的病灶少于标准剂量CT（Z = -3.368，P = 0.000），不过在检测≥5毫米的病灶方面，标准剂量和低剂量CT之间无统计学显著差异（Z = -0.055，P = 0.957）。此外，患者的风险评分也未受影响。低剂量CT对所有大小病灶的敏感度为69.16%，对<5毫米的病灶为58.50%，对5 - 10毫米的病灶为87.07%，对≥10毫米的病灶为97.01%。不同大小病灶的阳性预测值分别为80.71%（所有大小）、73.82%（5毫米）、88.86%（5 - 10毫米）和98.48%（≥10毫米）。
低剂量胸部CT可替代标准剂量胸部CT作为筛查和随访检查，以评估妊娠滋养细胞肿瘤患者肺转移情况的变化。
