目的:本研究的目的是在辐射暴露方面比较超低剂量(ULD)和标准低剂量(SLD)胸部计算机断层扫描(CT),对遗传性出血性毛细血管扩张症(HHT)患者肺动静脉畸形(AVM)的图像质量和诊断价值。
方法:在这项前瞻性委员会批准的研究中,前瞻性纳入了2020年12月至2022年1月期间转诊至参考中心进行筛查和/或随访胸部CT检查的连续HHT患者。患者在没有剂量调制的情况下接受了两次连续的非对比胸部CT(即,一个ULD协议[80kVp或100kVp,CTDIvol的0.3mGy或0.6mGy]和一个SLD协议[140kVp,CTDIvol为1.3mGy])。比较了两种方案在气管隆突水平上测得的客观图像噪声。总体图像质量和诊断置信度以4分Likert量表进行评分(1=不足至4=优秀)。灵敏度,特异性,使用SLD图像作为参考标准,计算ULDCT诊断供血动脉直径超过2mm的肺AVM的阳性预测值和阴性预测值,以及它们的95%置信区间(CI).
结果:共有44例HHT患者(31名女性;平均年龄,42±16[标准偏差(SD)]年;体重指数,包括23.2±4.5[SD]kg/m2)。在SLD图像中发现了34个动脉直径超过2mm的肺AVM,而在ULD图像中发现了35个。灵敏度,特异性,预测阳性值,ULDCT诊断PAVM的阴性预测值为100%(34/34;95%CI:90-100),96%(18/19;95%CI:74-100),97%(34/35;95%CI:85-100)和100%(18/18;95%CI:81-100),分别。在ULD(3.8±0.4[SD])和SLD(3.9±0.1[SD])CT图像之间,诊断置信度评分存在显着差异(P=0.03)。ULDCT检查(3.9±0.2[SD])和SLD(4±0[SD])CT检查的总体图像质量评分无差异(P=0.77)。ULD方案有效辐射剂量显著下降78.8%,ULDCT图像(16.7±5.0[SD]HU)和SLD图像(17.7±6.6[SD]HU)之间的噪声值没有显着差异(P=0.07)。
结论:ULD胸部CT对直径超过2mm的供血动脉的可治疗肺AVM的诊断具有100%的敏感性和96%的特异性,与标准低剂量方案相比,可节省78.8%的剂量。
OBJECTIVE: The purpose of this study was to compare ultra-low dose (ULD) and standard low-dose (SLD) chest computed tomography (CT) in terms of radiation exposure, image quality and diagnostic value for diagnosing pulmonary arteriovenous malformation (AVM) in patients with hereditary hemorrhagic
telangiectasia (HHT).
METHODS: In this prospective board-approved study consecutive patients with HHT referred to a reference center for screening and/or follow-up chest CT examination were prospectively included from December 2020 to January 2022. Patients underwent two consecutive non-contrast chest CTs without dose modulation (i.e., one ULD protocol [80 kVp or 100 kVp, CTDIvol of 0.3 mGy or 0.6 mGy] and one SLD protocol [140 kVp, CTDIvol of 1.3 mGy]). Objective image noises measured at the level of tracheal carina were compared between the two protocols. Overall image quality and diagnostic confidence were scored on a 4-point Likert scale (1 = insufficient to 4 = excellent). Sensitivity, specificity, positive predictive value and negative predictive value of ULD CT for diagnosing pulmonary AVM with a feeding artery of over 2 mm in diameter were calculated along with their 95% confidence intervals (CI) using SLD images as the standard of reference.
RESULTS: A total of 44 consecutive patients with HHT (31 women; mean age, 42 ± 16 [standard deviation (SD)] years; body mass index, 23.2 ± 4.5 [SD] kg/m2) were included. Thirty-four pulmonary AVMs with a feeding artery of over 2 mm in diameter were found with SLD images versus 35 with ULD images. Sensitivity, specificity, predictive positive value, and predictive negative value of ULD CT for the diagnosis of PAVM were 100% (34/34; 95% CI: 90-100), 96% (18/19; 95% CI: 74-100), 97% (34/35; 95% CI: 85-100) and 100% (18/18; 95% CI: 81-100), respectively. A significant difference in diagnostic confidence scores was found between ULD (3.8 ± 0.4 [SD]) and SLD (3.9 ± 0.1 [SD]) CT images (P = 0.03). No differences in overall image quality scores were found between ULD CT examinations (3.9 ± 0.2 [SD]) and SLD (4 ± 0 [SD]) CT examinations (P = 0.77). Effective radiation dose decreased significantly by 78.8% with ULD protocol, with no significant differences in noise values between ULD CT images (16.7 ± 5.0 [SD] HU) and SLD images (17.7 ± 6.6 [SD] HU) (P = 0.07).
CONCLUSIONS: ULD chest CT provides 100% sensitivity and 96% specificity for the diagnosis of treatable pulmonary AVM with a feeding artery of over 2 mm in diameter, leading to a 78.8% dose-saving compared with a standard low-dose protocol.