A Preliminary Study Of Contrast-enhanced Ultrasound In Lung Cancer

OBJECTIVE:The purpose of this study was to evaluate the enhancement pattern of lung cancer by using real-time gray-scale CEUS and time-intensity curves of ACQ software.MATERIALAND METHODS:A total of 50 patients with lung masses were recruited for the study.All patients were evaluated by traditional gray-scale sonography,color Doppler sonography,which provided a preliminary imaging diagnosis through scan for observation of the shape,size,internal echo,and vascular distribution of the lung lesions.Then,the gray-scale contrast-enhanced ultrasound was performed to observe the time to enhancement,the extent of enhancement and the dynamic enhancement pattern of each lesion.The parameters of arriver time(AT),time-to-peak(TTP) and peak intensity(PI) of each lesion were recorded and analyzed by quantitative software-ACQ to further characterize the lesions.RESULTS:1.Of the 50 patients,36 are diagnosed for peripheral lung carcinoma:14 adenocarcinoma,12 squamous carcinoma,3 small-cell carcinoma,5 metastatic tumor,1 large-cell carcinoma and lymphoepitheloid carcinomacarcinoma.14 are diagnosed for central lung carcinoma:3 adenocarcinoma,5 squamous carcinoma,2 small-cell carcinoma,2 metastatic tumor,1 adenosquamous carcinoma and 1 carcinoma sarcomatodes.2.1.12 peripheral lung carcinoma appeared echoless on gray-scale ultrasound were diagnosed as cystic lesions,their CEUS show different extent of enhancement(6 show hyper-enhancement,6 hypo-enhancement),thus diagnosed as solid lesion.2.2.Of the 36 peripheral lung carcinoma,18 show 0～Ⅰflow signal(13show patternⅡ+Ⅲand 5 patternⅠon CEUS),while 18 showⅡ～Ⅲflow signal(2 show patternⅡ+Ⅲand 16 pattern I on CEUS),there was no significant difference between CDFI and CEUS (P＞0.05).2.3.Of the 36 peripheral lung carcinoma,the study showed 21.4% (3/14)adenocarcinoma begin to enhance at "pulmonary arterial phase" enhancement, while 78.6%(11/14) at "bronchial arterial phase " enhancement;8.3%(1/12)squamous carcinoma begin to enhance at "pulmonary arterial phase" enhancement,while 91.7% (1/12)at "bronchial arterial phase" enhancement.There were no significance in the AT among different type of lung carcinoma(P＞0.05);On enhancement pattern:The study showed enhancement of typeⅠin 8 of 14(57.1%) adenocarcinoma,typeⅡin 6 of 14(42.9%) adenocarcinoma,while enhancement of typeⅠin 1 of 12(8.3%) squamous carcinoma,typeⅡin 9 of 12(75%) squamous carcinoma type;typeⅢin 2 of 12(16.7%) squamous carcinoma.There was significant difference in the enhancement pattern between adenocarcinoma and squamous carcinoma(P＜0.05).On enhancement extent:The study showed enhancement of typeⅠin 11 of 14(78.6%) adenocarcinoma,typeⅡin 3 of 14(21.4%) adenocarcinoma,while enhancement of typeⅠin 5 of 12(41.7%) squamous carcinoma,typeⅡin 7 of 12(58.3%) squamous carcinoma type;There was significant difference in the enhancement extent between adenocarcinoma and squamous carcinoma(P＜0.05).3 The sonogram features of central lung cancer with obstructive atelectasis(OA) by US,contrast-enhanced ultrasound.3.1.All of 14 obstructive atelectasis had inhomogeneous echotextue,with 9 hypo-or isoechoic echotexture,5 hyperechoic echotexture.Following administration of SonoVue,most of the OA(3 out of 14,78.6%) had a short time to enhancement (pulmonary arterial phase,between 1 and 6 s),the remain lesions(3 out of 14,21.4%) had a delayed time to enhancement,following a marked enhancement,both homogenenous(8 out of 14) and heterogeneous(6 out of 14).3.2.6 central tumors with OA appeared isoechoic echotexture compared with OA on gray-scale ultrasound were diagnosed as CA,their CEUS show heterogeneous and hypo-enhancement,thus confirmed as central tumors with OA.3.3.The AT,TTP of the OA were significantly earlier than those of the central lung cancer(5.13±1.99) vs(13.55±2.85) s,and(9.79±3.56) vs(22.30±3.68) s,respectively (both P＜0.001),the PI of the OA was significantly higher than that of the central lung cancer,(31.07±3.56) vs(14.58±2.56) dB(P＜0.001).4 There were no significance in the AT and TTP between central lung carcinoma and peripheral lung carcinoma(13.55±2.85s) vs(10.46±3.89s),(22.30±3.68s) vs (21.51±3.68s),respectively(both P＞0.05);but the PI in peripheral lung carcinoma was significantly higher than central lung carcinoma 14.58±2.56dB) vs(24.54±7.08 dB) (P＜0.05).CONCLUSIONS:1.CEUS can distinguish solid tumor from the cystic lesion by the perfusion of the contrast agent,which often seen at anechoic on gray-scale ultrasound when sound reflection at the aerated lung.2.Most lung cancer showed "bronchial arterial phase" enhancement,while absent of enhancement in "pulmonary arterial phase",this characteristic feature is of great important in lung cancer diagnosis.3.TypeⅠmostly represent enhancement pattern of adenocarcinoma,typeⅡmostly represent enhancement pattern of squamous carcinoma,the difference on the enhancement pattern is significantly(P＜0.05).4.TypeⅡmostly represent enhancement extent of squamous carcinoma,while typeⅠmostly represent enhancement extent of adenocarcinoma,the difference on the enhancement extent is significantly(P＜0.05).5.The central lung carcinoma with obstructive atelectasis(OA) demonstrated a characteristic pattern:most OA appeared a short AT until enhancement and marked contrast enhancement,while the central tumors appeared a delayed AT and faint enhancement.The AT,TTP of the OA were significantly earlier than those of the central lung cancer,the PI of the OA was significantly higher than that of the central lung cancer(all P＜0.05).There were no significance in the AT and TTP between the central lung carcinoma and the peripheral lung cancer(P＞0.05);but the PI in the peripheral lung cancer was significantly higher than the central lung carcinoma(P＜0.05).6.With gray-scale contrast-enhanced ultrasound,we can do better in differentiations of central lung tumor from OA..7.The study shows that the contrast-enhanced ultrasound of lung cancer has clinical application in certain situation,yet we are still lack experience on benign lung tumor, thus needing further investigation.