Mawlawi Osama, Erasmus Jeremy J, Munden Reginald F, Pan Tinsu, Knight Amy E, Macapinlac Homer A, Podoloff Donald A, Chasen Marvin
Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Box 56, Houston, TX 77030, USA.
AJR Am J Roentgenol. 2006 Feb;186(2):308-19. doi: 10.2214/AJR.04.1740.
The use of IV contrast media in PET/CT can result in an overestimation of PET attenuation factors that potentially can affect interpretation. The objective of this study was to quantify the effect of IV contrast media in PET/CT and assess its impact on patients with intrathoracic malignancies.
Nine patients had CTs performed with and without IV contrast media followed by (18)F-FDG PET. PET images were reconstructed using contrast-enhanced and unenhanced CT. To quantify the effect of contrast media on standardized uptake values (SUV), similar regions of interest (ROIs) were drawn on the subclavian vein, heart, liver, spleen, and site of malignancy on both CT and corresponding reconstructed PET images, and the mean and maximum values were compared. In addition, two physicians blinded to the imaging parameters that were used evaluated the reconstructed PET images to assess whether IV contrast media had an effect on clinical interpretation.
For all patient studies, the subclavian vein region on the ipsilateral side of contrast media administration had the highest increase in CT numbers with a corresponding average SUV(max) increase of 27.1%. Similarly, ROIs of the heart and at the site of malignancy showed an increase in the maximum attenuation value with a corresponding average SUV(max) increase of 16.7% and 8.4%, respectively. Other locations had relatively small attenuation value differences with a correspondingly negligible SUV variation.
Although there is a significant increase in SUV in regions of high-contrast concentration when contrast-enhanced CT is used for attenuation correction, this increase is clinically insignificant. Accordingly, in PET/CT, IV contrast-enhanced CT can be used in combination with the PET to evaluate patients with cancer.
在PET/CT中使用静脉注射造影剂可能会导致PET衰减因子的高估，这可能会影响诊断结果。本研究的目的是量化静脉注射造影剂在PET/CT中的影响，并评估其对胸内恶性肿瘤患者的影响。
9例患者在注射和未注射静脉造影剂的情况下进行CT扫描，随后进行（18）F-FDG PET检查。PET图像采用增强CT和未增强CT进行重建。为了量化造影剂对标准化摄取值（SUV）的影响，在CT和相应重建的PET图像上，在锁骨下静脉、心脏、肝脏、脾脏和恶性肿瘤部位绘制相似的感兴趣区域（ROI），并比较平均值和最大值。此外，两名对所使用的成像参数不知情的医生对重建的PET图像进行评估，以评估静脉造影剂是否对临床诊断有影响。
在所有患者研究中，注射造影剂同侧的锁骨下静脉区域CT值增加最高，相应的平均SUV（max）增加27.1%。同样，心脏和恶性肿瘤部位的ROI显示最大衰减值增加，相应的平均SUV（max）分别增加16.7%和8.4%。其他部位的衰减值差异相对较小，SUV变化相应可忽略不计。
虽然在使用增强CT进行衰减校正时，高对比度浓度区域的SUV有显著增加，但这种增加在临床上无显著意义。因此，在PET/CT中，静脉注射增强CT可与PET联合用于评估癌症患者。
