Engeler C E, Tashjian J H, Engeler C M, Geise R A, Holm J C, Ritenour E R
Department of Radiology, University of Minnesota Hospital, Minneapolis 55455.
AJR Am J Roentgenol. 1994 Jul;163(1):31-5. doi: 10.2214/ajr.163.1.8010241.
The purpose of this study was to evaluate the diagnostic accuracy and radiation dose of volumetric high-resolution CT in the diagnosis of interstitial lung disease and bronchiectasis when four contiguous sections were acquired at each of three levels. The potential benefits were weighed against the increased radiation dose of multiple scans.
High-resolution CT scans of four contiguous sections were obtained at each of three locations (the aortic arch, the carina, and 2 cm above the diaphragm) in 50 consecutive patients (mean age, 44 years old) with known or suspected interstitial lung disease or bronchiectasis who were referred for evaluation with high-resolution CT. Each individual scan was analyzed for the presence of motion-induced streaking, blurring, or doubling. The diagnostic information contained in each set of four scans was compared with that contained in the first of the four scans in the set.
Motion degraded at least one of the four images in each set in 69 (46%) of 150 volumetric acquisitions. When the full set of four images was considered instead of just the first scan from the set, the number of motion-free studies in patients with suboptimal respiratory suspension was increased by 40% (from 99 to 139). Diagnostic accuracy was improved as more features were identified on contiguous scans: the sensitivity of the first scan compared with that of the complete set of four scans was 84% for the detection of bronchiectasis, 97% for ground-glass opacity, 88% for honeycombing, 88% for septal thickening, and 86% for nodular opacities. Although the integral radiation exposure for a set of four CT scans was 2.8 times that of a single scan obtained with standard technique, peak skin exposure was unchanged. Slightly increased image noise with the reduced technique compromised diagnostic ability in 6% of studies.
The use of volumetric high-resolution CT increased diagnostic accuracy, particularly for bronchiectasis at the lung bases, without increasing peak skin radiation exposure. With the availability of four contiguous scans per anatomic level, the subjective confidence in interpretation and number of motion-free studies also increased.
本研究旨在评估当在三个层面的每一层获取四个连续层面图像时，容积式高分辨率CT在诊断间质性肺疾病和支气管扩张中的诊断准确性及辐射剂量。将潜在益处与多次扫描增加的辐射剂量进行权衡。
对50例连续的已知或疑似间质性肺疾病或支气管扩张且被转诊来行高分辨率CT评估的患者（平均年龄44岁），在三个位置（主动脉弓、隆突及膈肌上方2 cm）的每一处获取四个连续层面的高分辨率CT扫描图像。分析每一幅单独扫描图像是否存在运动导致的条纹、模糊或重叠。将每组四张扫描图像中包含的诊断信息与该组四张扫描图像中的第一张进行比较。
在150次容积式采集的图像中，69次（46%）采集的每组四张图像中至少有一幅图像因运动而质量下降。当考虑完整的四张图像而不仅仅是该组中的第一张扫描图像时，呼吸暂停不佳的患者中无运动伪影研究的数量增加了40%（从99次增加到139次）。随着在连续扫描中发现更多特征，诊断准确性得到提高：对于支气管扩张，第一张扫描图像与四张扫描图像完整组相比的敏感度为84%；对于磨玻璃影为97%；对于蜂窝状改变为88%；对于小叶间隔增厚为88%；对于结节状阴影为86%。尽管一组四张CT扫描的总辐射暴露量是采用标准技术单次扫描的2.8倍，但体表峰值暴露量未变。在6%的研究中，技术参数降低导致图像噪声略有增加，损害了诊断能力。
容积式高分辨率CT的应用提高了诊断准确性，尤其是对于肺底部的支气管扩张，且未增加体表峰值辐射暴露。由于每个解剖层面可获得四张连续扫描图像，解读的主观信心及无运动伪影研究的数量也有所增加。
