Imran M B, Kubota K, Yamada S, Fukuda H, Yamada K, Fujiwara T, Itoh M
Department of Nuclear Medicine and Radiology, Institute of Development, Aging and Cancer, Sendai, Japan.
J Nucl Med. 1998 Jul;39(7):1219-23.
The purpose of this study was to compare the diagnostic efficacy of attenuation-corrected and nonattenuation-corrected whole-body 18F-fluorodeoxyglucose (FDG) PET images to determine an adequate method that can semiquantitatively evaluate nonattenuation-corrected images.
Whole-body PET studies were performed in 24 fasting patients with various tumors (lung cancers, n = 18; mediastinal tumors, n = 4; breast cancers, n = 2) 30-40 min after a bolus injection of 18F-FDG. Transmission scans followed emission data acquisition. Reconstructed attenuation-corrected and uncorrected images were displayed simultaneously and the relative FDG uptake in lesions and corresponding background areas was evaluated by the region of interest method. Both types of images were also compared with X-CT scans and conventional nuclear medicine scans for diagnostic efficacy.
Attenuation-corrected and uncorrected images were found to be equally sensitive for detecting lesions. There was a strong linear correlation between lesion-to-background (L/B) ratios calculated on attenuation-corrected and uncorrected images (r = 0.98; p < 0.001). Significant differences in L/B ratios between attenuation-corrected and uncorrected images were present in only 6 of 55 lesions (11%). Standardized uptake ratios (SURs) in attenuation-uncorrected images did not correlate with SURs in attenuation-corrected images nor with L/B ratios in uncorrected images.
The efficacy of attenuation-uncorrected FDG PET images in evaluating tumors is similar to that using attenuation-corrected images. Uncorrected images provide not only clinically useful but also quantitative information equivalent to that provided by attenuation-corrected images. However the L/B ratio is the only available index that can be used for quantification of uncorrected images.
本研究的目的是比较衰减校正和未衰减校正的全身18F-氟脱氧葡萄糖（FDG）PET图像的诊断效能，以确定一种能够对未衰减校正图像进行半定量评估的适当方法。
对24例患有各种肿瘤（肺癌，n = 18；纵隔肿瘤，n = 4；乳腺癌，n = 2）的空腹患者进行全身PET研究，在静脉推注18F-FDG后30 - 40分钟进行。发射数据采集后进行透射扫描。同时显示重建的衰减校正图像和未校正图像，并通过感兴趣区方法评估病变及相应背景区域的相对FDG摄取。还将两种类型的图像与X-CT扫描和传统核医学扫描进行诊断效能比较。
发现衰减校正图像和未校正图像在检测病变方面同样敏感。在衰减校正图像和未校正图像上计算的病变与背景（L/B）比值之间存在强线性相关性（r = 0.98；p < 0.001）。在55个病变中，只有6个（11%）在衰减校正图像和未校正图像的L/B比值上存在显著差异。未衰减校正图像中的标准化摄取值（SURs）与衰减校正图像中的SURs以及未校正图像中的L/B比值均无相关性。
未衰减校正的FDG PET图像在评估肿瘤方面的效能与使用衰减校正图像相似。未校正图像不仅提供临床有用信息，还提供与衰减校正图像相当的定量信息。然而，L/B比值是可用于未校正图像定量的唯一可用指标。
