Lee Han A, Lee Young Hwan, Yoon Kwon-Ha, Bang Dong-Ho, Park Dong Eun
1 Department of Radiology, Wonkwang University Hospital, 895 Muwang-ro, Iksan 570-974, Korea.
2 Division of Hepatobiliary Surgery, Department of Surgery, Wonkwang University Hospital, Iksan, Korea.
AJR Am J Roentgenol. 2016 Jan;206(1):74-80. doi: 10.2214/AJR.15.14570.
The aim of this study was to compare gallstones on virtual unenhanced images and true unenhanced images acquired with dual-energy CT (DECT).
We enrolled 112 patients with right upper quadrant pain and clinically suspected acute cholecystitis or gallstone who underwent DECT--including unenhanced, arterial, and portal phases. Eighty-three gallstones with composition proven by semiquantitative Fourier transform infrared spectroscopy from 45 patients who had undergone cholecystectomy (40 cholesterol gallstones from 21 patients, 43 calcium gallstones from 24 patients) were included. CT images were retrospectively evaluated for stone size, contrast-to-noise ratio (CNR) of gallstone to bile, and visibility and density of gallstones for each image set. The visibility of each type of stone was compared with a paired t test.
Both cholesterol and calcium stones measured smaller on virtual unenhanced images than on true unenhanced images, yielding a lower sensitivity of virtual unenhanced images for detecting small gallstones. Mean CNR of cholesterol stones was 2.45 ± 1.32 versus 1.67 ± 1.55 (p < 0.032) and that of calcium stones was 10.59 ± 7.15 and 14.11 ± 9.81 (p < 0.001) for virtual unenhanced and true unenhanced images, respectively. For calcium stones, two readers found 43 of 43 (100%) on true unenhanced images; one reader found 41 of 43 (95%) and the other, 37 of 43 (86%) on virtual unenhanced images. For cholesterol stones, one reader found 20 of 40 (50%) and the other 19 of 40 (47%) on true unenhanced images versus 34 of 40 (85%) and 30 of 40 (75%), respectively, on virtual unenhanced images. The visibility of cholesterol stones was higher on virtual unenhanced images, but that of calcium stones was lower.
Virtual unenhanced images at DECT allow better visualization of cholesterol gallstones, but true unenhanced images allow better visualization of calcium and small gallstones.
本研究旨在比较双能CT（DECT）获取的虚拟平扫图像和真实平扫图像上的胆结石情况。
我们纳入了112例右上腹疼痛且临床怀疑急性胆囊炎或胆结石的患者，这些患者接受了DECT检查，包括平扫、动脉期和门静脉期。纳入了45例行胆囊切除术患者的83颗经半定量傅里叶变换红外光谱证实成分的胆结石（21例患者的40颗胆固醇结石，24例患者的43颗含钙结石）。对CT图像进行回顾性评估，以确定每组图像中结石大小、结石与胆汁的对比噪声比（CNR）以及结石的可见性和密度。使用配对t检验比较每种类型结石的可见性。
胆固醇结石和含钙结石在虚拟平扫图像上的测量尺寸均小于真实平扫图像，这使得虚拟平扫图像检测小胆结石的敏感性较低。胆固醇结石的平均CNR在虚拟平扫图像上为2.45±1.32，在真实平扫图像上为1.67±1.55（p<0.032）；含钙结石的平均CNR在虚拟平扫图像上为10.59±7.15，在真实平扫图像上为14.11±9.81（p<0.001）。对于含钙结石，两名阅片者在真实平扫图像上发现43颗中的43颗（100%）；一名阅片者在虚拟平扫图像上发现43颗中的41颗（95%），另一名阅片者发现43颗中的37颗（86%）。对于胆固醇结石，一名阅片者在真实平扫图像上发现40颗中的20颗（50%），另一名阅片者发现40颗中的19颗（47%）；而在虚拟平扫图像上分别为40颗中的34颗（85%）和40颗中的30颗（75%）。胆固醇结石在虚拟平扫图像上的可见性更高，但含钙结石的可见性更低。
DECT的虚拟平扫图像能更好地显示胆固醇结石，但真实平扫图像能更好地显示含钙结石和小胆结石。
