~(18)F-FDG PET-CT双时相显像及腹腔积液代谢测定对腹腔积液性质的鉴别诊断
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摘要
背景
正常人腹膜腔内有少量液体,对内脏起润滑作用,其体积一般应少于200ml。各种病理状态下导致腹腔内液体量超过200ml时,称为腹腔积液(也称为腹水)。临床工作中,通常将恶性肿瘤或其腹腔转移为主要原因所致的腹腔积液称作恶性腹腔积液,其余非恶性肿瘤病因所致腹腔积液如肝源性、心源性、肾源性及营养缺乏性腹腔积液等统称为良性腹腔积液。
以腹腔积液为首发病症的患者,尽快查明积液原因、明确积液性质是患者和医生面临的共同任务。恶性肿瘤细胞悬浮于腹腔积液内或定植于腹膜或其他腹腔脏器表面形成转移灶,通过腹腔积液细胞学检查发现恶性肿瘤细胞可直接确立恶性腹腔积液的诊断,而腹腔积液细胞学检测灵敏度只有30%-50%,多数恶性腹腔积液的性质难以经腹腔积液细胞学检测直接明确诊断,而腹腔积液细胞学检测阴性者又难以排除恶性腹腔积液的可能。超声、CT、MRI等检查是一种局部的解剖结构检查,加之腹腔脏器形态多变、肿瘤密度与腹腔脏器密度对比不著、肿瘤或转移灶位置隐匿等原因,部分腹腔积液患者经超声、CT、MRI、血生化及腹腔积液细胞学检测等常规检查后,积液原因、性质仍难以明确。
随着PET-CT临床应用的不断深入,’8F-脱氧葡萄糖(18F-FDG) PET-CT在肿瘤的早期诊断和分期中发挥了重要作用,在腹腔积液性质的鉴别诊断中也日渐被临床重视。由于18F-FDG为非特异性肿瘤显像剂,18F-FDG PET-CT常规显像中肿瘤定位诊断对恶性腹腔积液患者肿瘤原发灶及转移灶定位诊断存在一定的假阳性和假阴性。为提高]8F-FDG PET-CT的诊断效率,双时相显像在不少疾病的PET-CT诊断中得以应用,如肺结节的诊断等。对于腹腔积液的患者,除了应用双时相显像外,通过观察积液的放射性分布情况也可获得积液的代谢信息,从而提示积液的性质。但迄今为止,腹腔积液代谢方面的研究尚未见报道。
本课题分以下两个部分重点探讨了18F-FDG PET-CT检查中“双时相显像”和“腹腔积液代谢测定”对良、恶性腹腔积液的鉴别诊断价值,同时对腹腔积液代谢测定在恶性腹腔积液患者预后评价中的价值进行了初步探讨：
一、18F-FDG PET-CT双时相显像对腹腔积液患者肿瘤原发灶及腹膜转移灶的定位诊断价值；
二、18F-FDG PET-CT显像中腹腔积液代谢测定对良、恶性腹腔积液的辅助诊断及预后评估价值。
目的：
通过对腹腔积液患者18F-FDG PET-CT双时相显像及CT图像的分析对照,探讨18F-FDG PET-CT双时相显像对腹腔积液患者肿瘤原发灶及腹膜转移灶的定位诊断价值。
资料及方法：
回顾性分析2010年10月至2012年10月在笔者所在医院行18F-FDG PET-CT检查的腹腔积液患者89例,所有患者均于常规显像后行腹部延迟显像(双时相显像)。经临床随访、腹腔镜、腹腔积液细胞学、手术病理等最终明确诊断,包括良性腹腔积液21例、恶性腹腔积液68例,所有患者PET-CT检查前均无恶性肿瘤手术及其他治疗史。PET-CT及CT图像定位诊断分别由两名具有核医学及CT影像阅片经验的主治医师独立阅片,诊断意见不一致时,经相关医师共同阅片并讨论决定。利用感兴趣区(ROI)工具,分别测定肿瘤原发灶、腹膜转移灶的最大标准摄取值(SUVmax),多发腹膜转移灶者取SUVmax最高值纳入统计,腹膜炎患者测定放射性摄取最高区域的腹膜SUVmax,无腹膜炎的良性腹腔积液患者测定肠系膜SUVmax值。
采用统一的诊断标准对PET-CT及CT图像定位诊断的结果区分阴性和阳性,分别计算F-FDG PET-CT双时相显像及同机CT对肿瘤原发灶及腹膜转移灶定位诊断的灵敏度、特异性、准确性、阳性预测值及阴性预测值等指标,计算双时相显像病变的18F-FDG延迟上升率(increased rate of delay imaging, IRDI)。应用SPSS18.0统计分析软件对资料进行统计学处理及分析,率的比较采用四格表x2检验,定量资料两组间比较采用独立样本t检验,以约登指数(Youden index=Se+Sp-1)之最大点法确定各项指标的最佳判断标准(截断点),利用ROC曲线比较常规显像及延迟显像SUVmax值、双时相显像IRDI对肿瘤原发灶和腹膜转移灶的诊断价值,P<0.05定义为有统计学差异。
结果：
1、18F-FDG PET-CT双时相显像明显提高了肿瘤原发灶的检出率,尤其是原发性肝癌、胃癌和胰腺癌,正常肝脏、胃及胰腺随时间的延长生理摄取减低而肿瘤的FDG摄取出现升高,表现为“水落石出”的典型征象。双时相显像对恶性肿瘤原发灶定位诊断的灵敏度、准确率分别为76.5%、74.2%,同机CT对恶性肿瘤原发灶定位诊断的灵敏度、准确率分别为54.4%、53.9%,前者明显高于后者(x2=7.315,7.905；P均<0.05)。
2、18F-FDG PET-CT双时相显像可降低胃肠道蠕动和生理摄取的干扰,提高腹膜转移灶定位诊断的准确性。双时相显像对恶性腹腔积液患者腹膜转移灶定位诊断的灵敏度、特异性、准确性及阳性预测值分别为64.7%、85.7%、69.7%和93.6%,同机CT对恶性腹腔积液患者腹膜转移灶定位诊断的灵敏度、特异性、准确性及阳性预测值分别为47.1%、57.1%、49.4%和78.1%,前者明显高于后者(x2=4.29,4.20,7.56,4.51；P均<0.05)。
3、双时相显像肿瘤原发灶的IRDI为(45.0±63.1)%,腹膜转移灶为(13.6±41.2)%,腹膜良性病变为(-8.0±27.6)%,腹膜良性病变的IRDI值明显低于前两者(t=3.71,2.22；P均<0.05),其中肿瘤原发灶的IRDI为最高。
4、肿瘤原发灶的判断标准。以常规显像SUVmax>3.0为标准判断恶性腹腔积液患者肿瘤原发灶的灵敏度、特异性、准确性分别为64.7%、80.9%和68.5%,约登指数为0.456；以延迟显像SUVmax>3.0为标准判断恶性腹腔积液患者肿瘤原发灶的约登指数为0.714；以双时相显像IRDI>15%为判断标准的约登指数为0.533,三者的约登指数均大于相应指标其它水准的约登指数。常规显像SUVmax、延迟显像SUVmax及双时相IRDI三者ROC曲线下面积分别为0.764(P<0.05)、0.900(P<0.05)、0.778(P<0.05),表明三者对恶性腹腔积液患者肿瘤原发灶的诊断均具较高价值。
5、腹膜转移灶的判断标准。分别以常规显像SUVmax>2.0、延迟显像SUVmax>2.0、双时相显像[RDI>10%为标准,对腹膜转移灶诊断的约登指数分别为0.149、0.452和0.317,高于相应指标其他水准的约登指数。常规显像SUVmax、延迟显像SUVmax、双时相显像IRDI三者的ROC曲线下面积分别为0.620(P>0.05)、0.860(P<0.05)、0.724(P<0.05),表明延迟显像SUVmax和双时相显像IRDI对腹膜转移灶的诊断效率较高,而常规显像SUVmax曲线下面积小、对腹膜转移灶的诊断价值有限。
结论：
1、18F-FDG PET-CT双时相显像有效避免了腹腔脏器FDG生理性摄取较高而部分原发肿瘤FDG早期摄取“不够突出”的局限,延迟显像脏器生理摄取减低而肿瘤的FDG摄取出现升高,使肿瘤表现为“水落石出”的典型征象,对恶性腹腔积液患者肿瘤原发灶定位诊断的效率明显提高。
2、18F-FDG PET-CT双时相显像结合胃肠道对比剂的应用,可有效降低胃肠道蠕动和生理摄取的干扰,提高腹膜转移灶定位诊断的准确性,对恶性腹腔积液患者腹膜转移灶定位诊断的效率明显提高,有利于腹腔积液性质的鉴别诊断。
3、在18F-FDG PET-CT双时相显像中,以常规或延迟显像SUVmax>3.0、双时相显像IRDI>15%为判断标准,诊断恶性腹腔积液患者肿瘤原发灶具有较高价值。
4、以18F-FDG PET-CT延迟显像SUVmax>2.0、双时相显像IRDI>10%为判断标准,对于腹膜转移灶的诊断具有较高价值；单独常规显像SUVmax对腹膜转移灶的诊断价值有限。
目的：
分析良、恶性腹腔积液患者’8F-脱氧葡萄糖(18F-FDG) PET-CT显像腹腔积液代谢的特点,探讨腹腔积液代谢测定在腹腔积液辅助诊断中的价值及对恶性腹腔积液患者预后的评估作用。
资料及方法：
回顾性分析行首次18F-FDG PET-CT检查前病因不明、但随访诊断明确的腹腔积液患者55例,包括良性腹腔积液19例、恶性腹腔积液36例。分别测定常规显像和延迟显像腹腔积液标准摄取值(standardized uptake value, SUV),包括最大标准摄取值(SUVmax)及平均标准摄取值(SUVmean),分别计算其与正常肝脏的比值(分别记作T/NTmax和T/NTmean)，记录腹腔积液CEA、CA125及CA199测定结果并随访患者的生存期。腹腔积液18F-FDG代谢判定为腹腔积液放射性分布升高、肝影模糊者定义为腹腔积液代谢阳性,反之定义为腹腔积液代谢阴性。18F-FDG PET-CT未发现明确的异常代谢灶或异常肿物、发现异常代谢灶或异常肿物但诊断为炎症等良性病变者、诊断不明确建议进一步检查者均定义为PET/CT定位诊断阴性,发现明确的异常代谢灶诊断为恶性肿瘤或转移可能大者定义为PET/CT定位诊断阳性。PET/CT检查前及其后2周内任一次腹腔积液细胞学检查发现癌细胞即为腹腔积液细胞学检查阳性,反之为腹腔积液细胞学检查阴性。
计算18F-FDG PET/CT腹腔积液代谢、肿瘤定位诊断及腹腔积液细胞学检查鉴别腹腔积液的灵敏度、特异性、准确性等指标,行x2检验。分别统计常规显像和延迟显像良性腹腔积液和恶性腹腔积液的SUVmax、SUVmean、T/NTmax及T/NTmean,行两独立样本t检验。以约登指数(Youden index=Se+Sp-1)之最大点法确定各项指标的最佳判断标准(截断点)。利用ROC分析工具,比较常规显像腹腔积液T/NTmean、延迟显像T/NTmean、常规显像SUVmean、延迟显像SUVmean、腹腔积液CEA、腹腔积液CA125及腹腔积液CA199对不明原因腹腔积液的诊断价值,利用线性回归分析腹腔积液T/NTmean与患者生存时间的关系。
结果：
1.恶性腹腔积液患者18F-FDG PET/CT显像除可表现为高代谢的原发灶或／和转移灶外,腹腔积液代谢均匀性升高,高于正常肌肉组织,与肝脾代谢水平相接近,肝脾淹没于腹腔积液之中,最大密度投影图(MIP)上肝脾影像边界模糊,表现为“肝脾淹没征”,延迟显像上述特征更为显著。腹腔积液代谢判断恶性腹腔积液的灵敏度、特异性及准确性分别为75.0%、94.7%和81.8%,其灵敏度及准确性明显高于腹腔积液细胞学检测(x2=6.98,4.58；P均<0.05),其特异性明显高于PET／CT肿瘤定位诊断(x2=5.70,P<0.05)
2.常规显像良、恶性腹腔积液患者的积液SUVmean分别为0.72±0.22和1.37±0.38,后者明显高于前者(t=6.82,P<0.05)；常规显像良、恶性腹腔积液的T/NTmean分别为0.38±0.10和0.68±0.17,后者明显高于前者(t=7.21,P<0.05)恶性腹腔积液患者中细胞学检查阳性者的常规显像T/NTmean值为0.76±0.14,细胞学检查阴性者的常规显像T/NTmean值为0.62±0.16,前者明显高于后者(t==2.80；P<0.05)。延迟显像良性腹腔积液患者的积液SUVmean较常规显像呈下降趋势但变化不著(P>0.05),恶性腹腔积液患者的积液SUVmean较常规显像呈上升趋势但无统计学差异(P>0.05)。
3.以常规显像和延迟显像积液SUVmean>1.0作为恶性腹腔积液的判断标准具有较高的诊断效能(约登指数分别为0.620、0.673),以T/NTmean>0.5作为常规显像和延迟显像判断恶性腹腔积液的标准亦具较高的诊断效能(约登指数分别为0.650、0.675)。常规T/NTmean、延迟T/NTmean、常规SUVmean、延迟SUVean、积液CEA、积液CA125、积液CA199ROC曲线下面积分别为0.837(P<0.01)、0.871(P<0.01)、0.805(P<0.01)、0.836(P<0.01)、0.707(P<0.05)、0.561(P=0.463)、0.664(P<0.05)。腹腔积液SUVmean、T/NTmean曲线下面积明显大于各项腹腔积液肿瘤标志物检测,其中以延迟显像T/NTmean曲线下面积为最大(0.871)
4.腹腔积液患者生存期与双时相显像T/NTmean之间的关系经线性回归分析,相关系数分别为-0.647和-0.648,P均<0.01,说明腹腔积液患者的生存期与T／NT之间存在着较密切的负相关关系,即腹腔积液患者随积液代谢升高其生存期下降。
结论：
1.恶性腹腔积液患者18F-FDG PET/CT显像除可表现为高代谢的原发灶或/和转移灶外,腹腔积液代谢升高,与肝脾代谢水平相接近,MIP图像上肝脾影像边界模糊,表现为“肝脾淹没征”。利用腹腔积液代谢水平作为恶性腹腔积液鉴别诊断的一项观察指标,与肿瘤定位诊断相互补充,具备较高的辅助诊断价值。
2.在18F-FDG PET-CT常规显像和延迟显像中,以腹腔积液SUVmean>1.0或以腹腔积液与正常肝脏sUVmean(?)比值T/NT>0.5为判断标准均可对良、恶性腹腔积液进行有效地鉴别,腹腔积液SUVmean>1.0或T/NT>0.5均可考虑恶性腹腔积液的诊断。
3.腹腔积液患者的生存期与T/NT之间存在着较密切的负相关关系,即在不考虑患者治疗影响的情况下,积液T/NT值越高,患者的生存期可能越短。
Background
There is little free fluid in the abdominal cavity of healthy person, which is less than200mL for lubrication of the abdominal organs. Abnormal free fluid, usually more than200mL, aggregating in the abdominal cavity under pathologic conditions is recognized as ascites. Many diseases can cause ascites. Ascites caused by malignant tumor and its metastases is referred to malignant ascites, and ascites caused by other benign diseases, such as hepatic disease, heart disease, renal disease, and nutritional disease is referred to benign ascites.
It is the physician's responsibility to find out the cause of ascites as soon as possible for the patients with undetermined origin ascites. Malignant cells are suspended in the ascites fluid and can form permanent implantations on the peritoneum or on the surface of the abdominal organs. Ascites cytological examination is considered as the gold standard of diagnosing malignant ascites, but its sensitivity is low (usually between30%and50%). Ultrasound, CT, and MRI are mainly used for regional anatomic structure examination. The shapes of abdominal organs are changeable due to the respiratory movement and enterocinesi, and the metastases in peritoneum are usually small and delitescence. In clinical practice, original diseases of many ascites patients could not be determined by routine tests such as ultrasound, CT, MRI, or cytological examination.
With the greatly increased clinical application of positron emission tomography/computed tomography (PET/CT), the clinical value of18F-deoxyglucose (18F-FDG) PET/CT has been highlighted in the diagnosis of tumor diagnosis and staging. Consequently,18F-FDG PET/CT scans might be a useful option for examination of those patients with undetermined origin ascites. However,18F-FDG is a non-specific tracer agent that can be absorbed by malignant tumor or a few benign diseases and sometimes even not be absorbed by some malignant tumors, consequently causing the problem of false-positive or false-negative in tumor localization by18F-FDG PET/CT. Double-phase imaging has proved to be a good method to enhance the diagnostic efficiency of F-FDG PET/CT for many disease such as pulmonary lesions. Some information about FDG metabolism in ascites might be obtained through the measurement of the standard uptake value (SUV) of ascites and the observation of18F-FDG PET/CT images. Nevertheless, little information has been reported on ascites metabolism to date.
This study paid main attention to the differential diagnostic value of double-phase imaging and ascites metabolism measurement for ascites patients when performing18F-FDG PET-CT scan. The two parts below were included:
1) The diagnostic value of18F-FDG PET-CT double phase imaging in primary tumor and metastasis localization for ascites patients
2) Ascites metabolism measurement enhanced diagnostic value and prognostic evaluation in18F-FDG PET/CT for malignant ascites patients.
Objective:
Recently, accompany with the clinical application of positron emission tomography/computed tomography (PET/CT), the clinical value of18F-deoxyglucose (18F-FDG) PET/CT has been highlighted in the diagnosis and staging of malignant tumors.18F-FDG PET/CT has a high sensitivity that can detect malignant tumors in early stage due to their characteristics of high metabolic rate of glucose (MRGlc). The shapes of abdominal organs are changeable due to the respiratory movement and enterocinesi, and the metastases in peritoneum are usually small and delitescence, consequently causing the problem of false-positive or false-negative in tumor Iocalization by routine F-FDG PET/CT imaging. In this paper, Double-phase imaging and gastrointestinal tract contrast medium were used in18F-FDG PET/CT scan in order to enhance the diagnostic efficiency of primary tumor and metastasis localization for ascites patients.
Methods:
This was a retrospective study.89patients who were referred for18F-FDG PET/CT double phase imaging to determine the original cause of their ascites in October2010to October2012were reviewed for all their medical records. All patients including68of malignant ascites and21of benign ascites were confirmed by follow up such as CT, MRI, supersound, abdominal speculum, repeated ascites cytology or histopathology. There were no history of malignant tumor exairesis and other treatment for all cases. The interpretation of F-FDG PET/CT images and CT image was based on the consensus of two nuclear medicine physicians and two radiology physicians respectively. The maximum SUV (SUVmax) of primary tumor, metastasis, and the peritoneum of benign ascites patients were measured by elliptic region of interest (ROI) tools in fusion images. Those patients without positive results in primary tumor and metastasis in F-FDG PET/CT localization, the same region of the malignant lesions determined in follow up was used for SUVmax measurement. Statistical analysis was performed by PASW Statistics18software and the result with P<0.05was considered as statistically significant. The sensitivity, specificity and accuracy were calculated and compared by X2-test or Fisher's analysis among F-FDG PET/CT tumor localization and CT images based on the primary tumor and metastasis in peritoneum respectively. SUVmax of the primary tumor and metastasis or peritoneum were measured and checked by t-test. The value of increased rate of delay imaging (IRDI) was calculated by double phase PET/CT imaging. The ROC curve was used to analyze the diagnostic efficiency of F-FDG PET/CT routing imaging and delay imaging in metastasis of peritoneum according to SUVmax.
Results:
The sensitivity and accuracy of18F-FDG PET/CT double phase imaging in primary tumor localization of ascites patients were76.5%and74.2%. The sensitivity and accuracy of CT were54.4%and53.9%. The former were higher than the latter (X2=7.31,7.90; P all<0.05). Delay imaging promoted the sensitivity of18F-FDG PET/CT for primary tumor of ascites patients, especially for the patients with primary hepatic carcinoma, gastric cancer, and pancreatic carcinoma.
The sensitivity, specificity, accuracy and positive predictive value of F-FDG PET/CT double phase imaging in peritoneum metastasis localization of ascites patients were64.7%,85.7%,69.7%, and93.6%. Those of CT were47.1%,57.1%,49.4%, and78.1%. The former were higher than the latter (X2=4.29,4.20,7.56,4.51; P all<0.05).
The IRDI of primary tumors calculated by double phases PET/CT imaging was (45.0±63.1)%, those of peritoneum metastasis and benign lesions in peritoneum were (13.6±41.2)%and (-8.0±27.6)%. The latter was much lower than the two formers (t=3.71,2.22; Pall<0.05).
SUVmax>3.0in routine imaging and delay imaging, IRDI>15%in double phases imaging discriminated primary malignant tumor efficiently. SUVmax>2.0in delay imaging, IRDI>10%in double phases imaging discriminated peritoneum metastasis efficiently. The area under ROC curve of SUVmax in delay imaging was the larger than that of routine imaging and IRDI in double phases imaging.
Conclusion:
18F-FDG PET/CT double phase imaging promoted the diagnostic efficiency in primary tumor localization of ascites patients, which could demonstrate the continuous uptake of FDG in gastrointestinal primary tumor.
18F-FDG PET/CT double phase imaging accompany with the use of gastrointestinal tract contrast medium could successfully promote the diagnostic accuracy of peritoneum metastasis for ascites patients.
SUVmax>3.0in18F-FDG PET/CT routine or delay imaging or IRDI>15%could be considered as efficient index to promoted the diagnostic efficiency in primary tumor localization of ascites patients.
SUVmax measurement in'8F-FDG PET/CT double phase imaging is a good method to promote the diagnostic efficiency of peritoneum metastasis for ascites patients. SUVmax>2.0in delay imaging or IRDI>10%in double phases imaging were good index for peritoneum metastasis discriminated diagnosis.
Objective
With the greatly increased clinical application of positron emission tomography/computed tomography (PET/CT), the clinical value of F-deoxyglucose (18F-FDG) PET/CT has been highlighted in the diagnosis of malignant ascites. However, F-FDG is a non-specific tracer agent that can be absorbed by malignant tumor or a few benign diseases and sometimes even not be absorbed by some malignant tumors, consequently causing the problem of false-positive or false-negative in tumor localization by F-FDG PET/CT. To date, little information has been reported on ascites metabolism. Nevertheless, some information about FDG metabolism in ascites might be obtained through the measurement of the standard uptake value (SUV) of ascites and the observation of F-FDG PET/CT images. This study aimed to evaluate the role of ascites metabolism measurement in F-FDG PET/CT for auxiliary diagnosis and prognostic evaluation of malignant ascites.
Methods
This study reviewed all the medical records of55patients that underwent F-FDG PET/CT to determine the original cause of ascites. Among these55cases of ascites patients,36cases were malignant ascites and19cases were benign ascites. All patients underwent ascites CEA, ascites CA125, ascites CA199and ascites cytology examinations before or within two weeks after F-FDG PET/CT scans. The patients with negative results of ascites cytology were confirmed by clinical follow-up (including CT, MRI, supersound, abdominal speculum, repeated ascites cytology or histopathology). F-FDG PET/CT scan was performed on a PET/CT system. The scan field ranged from the head to middle of the thigh. Seven to8bed positions were usually required and the emission images were acquired for2.5min per bed position. Delayed imaging was performed50to90min after the first PET/CT scan according to the requirements of diagnosis.
The mean SUV (SUVmean) of ascites and liver were measured by elliptic region of interest (ROI) tools in fusion images. The SUV ratio of ascites and liver, denoted as T/NT, was calculated based on the SUVmean. The interpretation of18F-FDG PET/CT images was based on the consensus of two nuclear medicine physicians. Ascites metabolism measurement was based on the value of T/NT and the experience of nuclear medicine physicians. Ascites metabolism measurement was defined as positive if the ascites was found to increase the radioactivity uptake or the shapes of the liver and spleen were vague in maximum intensity projection (MIP) images. Otherwise, it was defined as negative. If definite lumps or abnormal metabolic foci were not found in F-FDG PET/CT images or they were found but interpreted as benign disease or no definite diagnosis was given, the18F-FDG PET/CT tumor localization was defined as negative. On the contrary, if definite abnormal metabolic foci or abnormal lumps were found and an interpretation of malignant tumor or metastasis was given, the F-FDG PET/CT tumor localization was defined as positive.Ascites cytology examination was performed before the first18F-FDG PET/CT or two weeks after. If malignant tumor cells were found, the result of ascites cytology examination was defined as positive. On the contrary, it was defined as negative.
Statistical analysis was performed by PASW Statistics18software and the result with P<0.05was considered as statistically significant. The sensitivity, specificity and accuracy were calculated and compared by X2-test or Fisher's analysis among F-FDG PET/CT ascites metabolism measurement, tumor localization, and ascites cytology examination. SUVmean of the ascites and liver were measured and the T/NT value was calculated and checked by t-test. The ROC curve was used to analyze the diagnostic efficiency of ascites T/NT, ascites CEA, ascites CA125, and ascites CA199. And the linear regression was used to analyze the relationship between ascites T/NT and the survival time of patients.
Results In cases of malignant ascites, the characteristics of immersed liver and spleen could be seen in those patients with widespread tiny metastasis in peritoneum in MIP images. In slice images of those patients, increased radioactive uptake was seen around peritoneum and intestinal canal, and the ascites metabolic level was lower in center and higher on verge. The sensitivity and accuracy of ascites metabolism measurement were higher than those of ascites cytology examination (X2=6.98,4.58; P all<0.05). The specificity of ascites metabolism measurement was higher than that of18F-FDG PET/CT tumor localization (X2=5.70, P<0.05).
The SUVmean of malignant ascites in routine imaging wasl.37±0.38. That of benign ascites was0.72±0.22. the former was higher than the latter (i=6.82, P<0.05). Based on the criteria of SUVmean>1.0, the sensitivity, specificity and accuracy were77.8%,84.2%, and81.8%respectively. The T/NT values of benign and malignant ascites were0.38±0.10and0.68±0.17, respectively, indicating that the latter was higher than the former (t=7.21, P<0.05). Nevertheless, the T/NT value of malignant ascites patients with positive results of ascites cytology examination was0.76±0.14, and that with negative results was0.62±0.16, indicating that the former was higher than the latter (t=2.80; P<0.05). Based on the criteria of T/NT>0.5, the sensitivity, specificity and accuracy were86.1%,78.9%, and83.6%respectively.
The area under ROC curve of T/NTmean in routine imaging, T/NTmean in delay imaging, SUVmean in routine imaging, SUVmea,in delay imaging, ascites CEA, ascites CA125and ascites CA199was0.837(P<0.01),0.871(P<0.01),0.805(P<0.01),0.836(P<0.01),0.707(P<0.05),0.561(P=0.463) and0.664(P<0.05), respectively. The area under ROC curve of SUVmean and T/NTmean were the larger than others. The area under ROC curve of ascites CA125was lower due to its abnormal increase in some benign ascites such as hepatic cirrhosis ascites and tuberculous ascites. There was a negative correlation between the survival of patients with malignant ascites and ascites T/NT (r=-0.647, P<0.01). The higher the ascites metabolism level was, the shorter survival time the patient would have.
Conclusion
1. In cases of malignant ascites, the characteristics of immersed liver and spleen could be seen in those patients with widespread tiny metastasis in peritoneum in18F-FDG PET/CT MIP images.Ascites metabolism measurement was good for differential diagnosis of malignant ascites, and has an important auxiliary diagnostic value for ascites patients.
2. The SUV ratio of ascites and liver in18F-FDG PET/CT imaging, denoted as T/NT, was helpful to determine the nature of ascites diagnosis. SUVmean>1.0and T/NTmean>0.5were good index for differential diagnosis of ascites. The T/NT and SUVmean of ascites were better than ascites CEA, ascites CA125, and ascites CA199in differential diagnosis of ascites.
3. There was a negative correlation between the survival of patients with malignant ascites and ascites T/NTmean, which may be a good index for prognostic evaluation of malignant ascites
正常人腹膜腔内有少量液体,对内脏起润滑作用,其体积一般应少于200ml。各种病理状态下导致腹腔内液体量超过200ml时,称为腹腔积液(也称为腹水)。临床工作中,通常将恶性肿瘤或其腹腔转移为主要原因所致的腹腔积液称作恶性腹腔积液,其余非恶性肿瘤病因所致腹腔积液如肝源性、心源性、肾源性及营养缺乏性腹腔积液等统称为良性腹腔积液。
以腹腔积液为首发病症的患者,尽快查明积液原因、明确积液性质是患者和医生面临的共同任务。恶性肿瘤细胞悬浮于腹腔积液内或定植于腹膜或其他腹腔脏器表面形成转移灶,通过腹腔积液细胞学检查发现恶性肿瘤细胞可直接确立恶性腹腔积液的诊断,而腹腔积液细胞学检测灵敏度只有30%-50%,多数恶性腹腔积液的性质难以经腹腔积液细胞学检测直接明确诊断,而腹腔积液细胞学检测阴性者又难以排除恶性腹腔积液的可能。超声、CT、MRI等检查是一种局部的解剖结构检查,加之腹腔脏器形态多变、肿瘤密度与腹腔脏器密度对比不著、肿瘤或转移灶位置隐匿等原因,部分腹腔积液患者经超声、CT、MRI、血生化及腹腔积液细胞学检测等常规检查后,积液原因、性质仍难以明确。
随着PET-CT临床应用的不断深入,’8F-脱氧葡萄糖(18F-FDG) PET-CT在肿瘤的早期诊断和分期中发挥了重要作用,在腹腔积液性质的鉴别诊断中也日渐被临床重视。由于18F-FDG为非特异性肿瘤显像剂,18F-FDG PET-CT常规显像中肿瘤定位诊断对恶性腹腔积液患者肿瘤原发灶及转移灶定位诊断存在一定的假阳性和假阴性。为提高]8F-FDG PET-CT的诊断效率,双时相显像在不少疾病的PET-CT诊断中得以应用,如肺结节的诊断等。对于腹腔积液的患者,除了应用双时相显像外,通过观察积液的放射性分布情况也可获得积液的代谢信息,从而提示积液的性质。但迄今为止,腹腔积液代谢方面的研究尚未见报道。
本课题分以下两个部分重点探讨了18F-FDG PET-CT检查中“双时相显像”和“腹腔积液代谢测定”对良、恶性腹腔积液的鉴别诊断价值,同时对腹腔积液代谢测定在恶性腹腔积液患者预后评价中的价值进行了初步探讨：
一、18F-FDG PET-CT双时相显像对腹腔积液患者肿瘤原发灶及腹膜转移灶的定位诊断价值；
二、18F-FDG PET-CT显像中腹腔积液代谢测定对良、恶性腹腔积液的辅助诊断及预后评估价值。
目的：
通过对腹腔积液患者18F-FDG PET-CT双时相显像及CT图像的分析对照,探讨18F-FDG PET-CT双时相显像对腹腔积液患者肿瘤原发灶及腹膜转移灶的定位诊断价值。
资料及方法：
回顾性分析2010年10月至2012年10月在笔者所在医院行18F-FDG PET-CT检查的腹腔积液患者89例,所有患者均于常规显像后行腹部延迟显像(双时相显像)。经临床随访、腹腔镜、腹腔积液细胞学、手术病理等最终明确诊断,包括良性腹腔积液21例、恶性腹腔积液68例,所有患者PET-CT检查前均无恶性肿瘤手术及其他治疗史。PET-CT及CT图像定位诊断分别由两名具有核医学及CT影像阅片经验的主治医师独立阅片,诊断意见不一致时,经相关医师共同阅片并讨论决定。利用感兴趣区(ROI)工具,分别测定肿瘤原发灶、腹膜转移灶的最大标准摄取值(SUVmax),多发腹膜转移灶者取SUVmax最高值纳入统计,腹膜炎患者测定放射性摄取最高区域的腹膜SUVmax,无腹膜炎的良性腹腔积液患者测定肠系膜SUVmax值。
采用统一的诊断标准对PET-CT及CT图像定位诊断的结果区分阴性和阳性,分别计算F-FDG PET-CT双时相显像及同机CT对肿瘤原发灶及腹膜转移灶定位诊断的灵敏度、特异性、准确性、阳性预测值及阴性预测值等指标,计算双时相显像病变的18F-FDG延迟上升率(increased rate of delay imaging, IRDI)。应用SPSS18.0统计分析软件对资料进行统计学处理及分析,率的比较采用四格表x2检验,定量资料两组间比较采用独立样本t检验,以约登指数(Youden index=Se+Sp-1)之最大点法确定各项指标的最佳判断标准(截断点),利用ROC曲线比较常规显像及延迟显像SUVmax值、双时相显像IRDI对肿瘤原发灶和腹膜转移灶的诊断价值,P<0.05定义为有统计学差异。
结果：
1、18F-FDG PET-CT双时相显像明显提高了肿瘤原发灶的检出率,尤其是原发性肝癌、胃癌和胰腺癌,正常肝脏、胃及胰腺随时间的延长生理摄取减低而肿瘤的FDG摄取出现升高,表现为“水落石出”的典型征象。双时相显像对恶性肿瘤原发灶定位诊断的灵敏度、准确率分别为76.5%、74.2%,同机CT对恶性肿瘤原发灶定位诊断的灵敏度、准确率分别为54.4%、53.9%,前者明显高于后者(x2=7.315,7.905；P均<0.05)。
2、18F-FDG PET-CT双时相显像可降低胃肠道蠕动和生理摄取的干扰,提高腹膜转移灶定位诊断的准确性。双时相显像对恶性腹腔积液患者腹膜转移灶定位诊断的灵敏度、特异性、准确性及阳性预测值分别为64.7%、85.7%、69.7%和93.6%,同机CT对恶性腹腔积液患者腹膜转移灶定位诊断的灵敏度、特异性、准确性及阳性预测值分别为47.1%、57.1%、49.4%和78.1%,前者明显高于后者(x2=4.29,4.20,7.56,4.51；P均<0.05)。
3、双时相显像肿瘤原发灶的IRDI为(45.0±63.1)%,腹膜转移灶为(13.6±41.2)%,腹膜良性病变为(-8.0±27.6)%,腹膜良性病变的IRDI值明显低于前两者(t=3.71,2.22；P均<0.05),其中肿瘤原发灶的IRDI为最高。
4、肿瘤原发灶的判断标准。以常规显像SUVmax>3.0为标准判断恶性腹腔积液患者肿瘤原发灶的灵敏度、特异性、准确性分别为64.7%、80.9%和68.5%,约登指数为0.456；以延迟显像SUVmax>3.0为标准判断恶性腹腔积液患者肿瘤原发灶的约登指数为0.714；以双时相显像IRDI>15%为判断标准的约登指数为0.533,三者的约登指数均大于相应指标其它水准的约登指数。常规显像SUVmax、延迟显像SUVmax及双时相IRDI三者ROC曲线下面积分别为0.764(P<0.05)、0.900(P<0.05)、0.778(P<0.05),表明三者对恶性腹腔积液患者肿瘤原发灶的诊断均具较高价值。
5、腹膜转移灶的判断标准。分别以常规显像SUVmax>2.0、延迟显像SUVmax>2.0、双时相显像[RDI>10%为标准,对腹膜转移灶诊断的约登指数分别为0.149、0.452和0.317,高于相应指标其他水准的约登指数。常规显像SUVmax、延迟显像SUVmax、双时相显像IRDI三者的ROC曲线下面积分别为0.620(P>0.05)、0.860(P<0.05)、0.724(P<0.05),表明延迟显像SUVmax和双时相显像IRDI对腹膜转移灶的诊断效率较高,而常规显像SUVmax曲线下面积小、对腹膜转移灶的诊断价值有限。
结论：
1、18F-FDG PET-CT双时相显像有效避免了腹腔脏器FDG生理性摄取较高而部分原发肿瘤FDG早期摄取“不够突出”的局限,延迟显像脏器生理摄取减低而肿瘤的FDG摄取出现升高,使肿瘤表现为“水落石出”的典型征象,对恶性腹腔积液患者肿瘤原发灶定位诊断的效率明显提高。
2、18F-FDG PET-CT双时相显像结合胃肠道对比剂的应用,可有效降低胃肠道蠕动和生理摄取的干扰,提高腹膜转移灶定位诊断的准确性,对恶性腹腔积液患者腹膜转移灶定位诊断的效率明显提高,有利于腹腔积液性质的鉴别诊断。
3、在18F-FDG PET-CT双时相显像中,以常规或延迟显像SUVmax>3.0、双时相显像IRDI>15%为判断标准,诊断恶性腹腔积液患者肿瘤原发灶具有较高价值。
4、以18F-FDG PET-CT延迟显像SUVmax>2.0、双时相显像IRDI>10%为判断标准,对于腹膜转移灶的诊断具有较高价值；单独常规显像SUVmax对腹膜转移灶的诊断价值有限。
目的：
分析良、恶性腹腔积液患者’8F-脱氧葡萄糖(18F-FDG) PET-CT显像腹腔积液代谢的特点,探讨腹腔积液代谢测定在腹腔积液辅助诊断中的价值及对恶性腹腔积液患者预后的评估作用。
资料及方法：
回顾性分析行首次18F-FDG PET-CT检查前病因不明、但随访诊断明确的腹腔积液患者55例,包括良性腹腔积液19例、恶性腹腔积液36例。分别测定常规显像和延迟显像腹腔积液标准摄取值(standardized uptake value, SUV),包括最大标准摄取值(SUVmax)及平均标准摄取值(SUVmean),分别计算其与正常肝脏的比值(分别记作T/NTmax和T/NTmean)，记录腹腔积液CEA、CA125及CA199测定结果并随访患者的生存期。腹腔积液18F-FDG代谢判定为腹腔积液放射性分布升高、肝影模糊者定义为腹腔积液代谢阳性,反之定义为腹腔积液代谢阴性。18F-FDG PET-CT未发现明确的异常代谢灶或异常肿物、发现异常代谢灶或异常肿物但诊断为炎症等良性病变者、诊断不明确建议进一步检查者均定义为PET/CT定位诊断阴性,发现明确的异常代谢灶诊断为恶性肿瘤或转移可能大者定义为PET/CT定位诊断阳性。PET/CT检查前及其后2周内任一次腹腔积液细胞学检查发现癌细胞即为腹腔积液细胞学检查阳性,反之为腹腔积液细胞学检查阴性。
计算18F-FDG PET/CT腹腔积液代谢、肿瘤定位诊断及腹腔积液细胞学检查鉴别腹腔积液的灵敏度、特异性、准确性等指标,行x2检验。分别统计常规显像和延迟显像良性腹腔积液和恶性腹腔积液的SUVmax、SUVmean、T/NTmax及T/NTmean,行两独立样本t检验。以约登指数(Youden index=Se+Sp-1)之最大点法确定各项指标的最佳判断标准(截断点)。利用ROC分析工具,比较常规显像腹腔积液T/NTmean、延迟显像T/NTmean、常规显像SUVmean、延迟显像SUVmean、腹腔积液CEA、腹腔积液CA125及腹腔积液CA199对不明原因腹腔积液的诊断价值,利用线性回归分析腹腔积液T/NTmean与患者生存时间的关系。
结果：
1.恶性腹腔积液患者18F-FDG PET/CT显像除可表现为高代谢的原发灶或／和转移灶外,腹腔积液代谢均匀性升高,高于正常肌肉组织,与肝脾代谢水平相接近,肝脾淹没于腹腔积液之中,最大密度投影图(MIP)上肝脾影像边界模糊,表现为“肝脾淹没征”,延迟显像上述特征更为显著。腹腔积液代谢判断恶性腹腔积液的灵敏度、特异性及准确性分别为75.0%、94.7%和81.8%,其灵敏度及准确性明显高于腹腔积液细胞学检测(x2=6.98,4.58；P均<0.05),其特异性明显高于PET／CT肿瘤定位诊断(x2=5.70,P<0.05)
2.常规显像良、恶性腹腔积液患者的积液SUVmean分别为0.72±0.22和1.37±0.38,后者明显高于前者(t=6.82,P<0.05)；常规显像良、恶性腹腔积液的T/NTmean分别为0.38±0.10和0.68±0.17,后者明显高于前者(t=7.21,P<0.05)恶性腹腔积液患者中细胞学检查阳性者的常规显像T/NTmean值为0.76±0.14,细胞学检查阴性者的常规显像T/NTmean值为0.62±0.16,前者明显高于后者(t==2.80；P<0.05)。延迟显像良性腹腔积液患者的积液SUVmean较常规显像呈下降趋势但变化不著(P>0.05),恶性腹腔积液患者的积液SUVmean较常规显像呈上升趋势但无统计学差异(P>0.05)。
3.以常规显像和延迟显像积液SUVmean>1.0作为恶性腹腔积液的判断标准具有较高的诊断效能(约登指数分别为0.620、0.673),以T/NTmean>0.5作为常规显像和延迟显像判断恶性腹腔积液的标准亦具较高的诊断效能(约登指数分别为0.650、0.675)。常规T/NTmean、延迟T/NTmean、常规SUVmean、延迟SUVean、积液CEA、积液CA125、积液CA199ROC曲线下面积分别为0.837(P<0.01)、0.871(P<0.01)、0.805(P<0.01)、0.836(P<0.01)、0.707(P<0.05)、0.561(P=0.463)、0.664(P<0.05)。腹腔积液SUVmean、T/NTmean曲线下面积明显大于各项腹腔积液肿瘤标志物检测,其中以延迟显像T/NTmean曲线下面积为最大(0.871)
4.腹腔积液患者生存期与双时相显像T/NTmean之间的关系经线性回归分析,相关系数分别为-0.647和-0.648,P均<0.01,说明腹腔积液患者的生存期与T／NT之间存在着较密切的负相关关系,即腹腔积液患者随积液代谢升高其生存期下降。
结论：
1.恶性腹腔积液患者18F-FDG PET/CT显像除可表现为高代谢的原发灶或/和转移灶外,腹腔积液代谢升高,与肝脾代谢水平相接近,MIP图像上肝脾影像边界模糊,表现为“肝脾淹没征”。利用腹腔积液代谢水平作为恶性腹腔积液鉴别诊断的一项观察指标,与肿瘤定位诊断相互补充,具备较高的辅助诊断价值。
2.在18F-FDG PET-CT常规显像和延迟显像中,以腹腔积液SUVmean>1.0或以腹腔积液与正常肝脏sUVmean(?)比值T/NT>0.5为判断标准均可对良、恶性腹腔积液进行有效地鉴别,腹腔积液SUVmean>1.0或T/NT>0.5均可考虑恶性腹腔积液的诊断。
3.腹腔积液患者的生存期与T/NT之间存在着较密切的负相关关系,即在不考虑患者治疗影响的情况下,积液T/NT值越高,患者的生存期可能越短。
Background
There is little free fluid in the abdominal cavity of healthy person, which is less than200mL for lubrication of the abdominal organs. Abnormal free fluid, usually more than200mL, aggregating in the abdominal cavity under pathologic conditions is recognized as ascites. Many diseases can cause ascites. Ascites caused by malignant tumor and its metastases is referred to malignant ascites, and ascites caused by other benign diseases, such as hepatic disease, heart disease, renal disease, and nutritional disease is referred to benign ascites.
It is the physician's responsibility to find out the cause of ascites as soon as possible for the patients with undetermined origin ascites. Malignant cells are suspended in the ascites fluid and can form permanent implantations on the peritoneum or on the surface of the abdominal organs. Ascites cytological examination is considered as the gold standard of diagnosing malignant ascites, but its sensitivity is low (usually between30%and50%). Ultrasound, CT, and MRI are mainly used for regional anatomic structure examination. The shapes of abdominal organs are changeable due to the respiratory movement and enterocinesi, and the metastases in peritoneum are usually small and delitescence. In clinical practice, original diseases of many ascites patients could not be determined by routine tests such as ultrasound, CT, MRI, or cytological examination.
With the greatly increased clinical application of positron emission tomography/computed tomography (PET/CT), the clinical value of18F-deoxyglucose (18F-FDG) PET/CT has been highlighted in the diagnosis of tumor diagnosis and staging. Consequently,18F-FDG PET/CT scans might be a useful option for examination of those patients with undetermined origin ascites. However,18F-FDG is a non-specific tracer agent that can be absorbed by malignant tumor or a few benign diseases and sometimes even not be absorbed by some malignant tumors, consequently causing the problem of false-positive or false-negative in tumor localization by18F-FDG PET/CT. Double-phase imaging has proved to be a good method to enhance the diagnostic efficiency of F-FDG PET/CT for many disease such as pulmonary lesions. Some information about FDG metabolism in ascites might be obtained through the measurement of the standard uptake value (SUV) of ascites and the observation of18F-FDG PET/CT images. Nevertheless, little information has been reported on ascites metabolism to date.
This study paid main attention to the differential diagnostic value of double-phase imaging and ascites metabolism measurement for ascites patients when performing18F-FDG PET-CT scan. The two parts below were included:
1) The diagnostic value of18F-FDG PET-CT double phase imaging in primary tumor and metastasis localization for ascites patients
2) Ascites metabolism measurement enhanced diagnostic value and prognostic evaluation in18F-FDG PET/CT for malignant ascites patients.
Objective:
Recently, accompany with the clinical application of positron emission tomography/computed tomography (PET/CT), the clinical value of18F-deoxyglucose (18F-FDG) PET/CT has been highlighted in the diagnosis and staging of malignant tumors.18F-FDG PET/CT has a high sensitivity that can detect malignant tumors in early stage due to their characteristics of high metabolic rate of glucose (MRGlc). The shapes of abdominal organs are changeable due to the respiratory movement and enterocinesi, and the metastases in peritoneum are usually small and delitescence, consequently causing the problem of false-positive or false-negative in tumor Iocalization by routine F-FDG PET/CT imaging. In this paper, Double-phase imaging and gastrointestinal tract contrast medium were used in18F-FDG PET/CT scan in order to enhance the diagnostic efficiency of primary tumor and metastasis localization for ascites patients.
Methods:
This was a retrospective study.89patients who were referred for18F-FDG PET/CT double phase imaging to determine the original cause of their ascites in October2010to October2012were reviewed for all their medical records. All patients including68of malignant ascites and21of benign ascites were confirmed by follow up such as CT, MRI, supersound, abdominal speculum, repeated ascites cytology or histopathology. There were no history of malignant tumor exairesis and other treatment for all cases. The interpretation of F-FDG PET/CT images and CT image was based on the consensus of two nuclear medicine physicians and two radiology physicians respectively. The maximum SUV (SUVmax) of primary tumor, metastasis, and the peritoneum of benign ascites patients were measured by elliptic region of interest (ROI) tools in fusion images. Those patients without positive results in primary tumor and metastasis in F-FDG PET/CT localization, the same region of the malignant lesions determined in follow up was used for SUVmax measurement. Statistical analysis was performed by PASW Statistics18software and the result with P<0.05was considered as statistically significant. The sensitivity, specificity and accuracy were calculated and compared by X2-test or Fisher's analysis among F-FDG PET/CT tumor localization and CT images based on the primary tumor and metastasis in peritoneum respectively. SUVmax of the primary tumor and metastasis or peritoneum were measured and checked by t-test. The value of increased rate of delay imaging (IRDI) was calculated by double phase PET/CT imaging. The ROC curve was used to analyze the diagnostic efficiency of F-FDG PET/CT routing imaging and delay imaging in metastasis of peritoneum according to SUVmax.
Results:
The sensitivity and accuracy of18F-FDG PET/CT double phase imaging in primary tumor localization of ascites patients were76.5%and74.2%. The sensitivity and accuracy of CT were54.4%and53.9%. The former were higher than the latter (X2=7.31,7.90; P all<0.05). Delay imaging promoted the sensitivity of18F-FDG PET/CT for primary tumor of ascites patients, especially for the patients with primary hepatic carcinoma, gastric cancer, and pancreatic carcinoma.
The sensitivity, specificity, accuracy and positive predictive value of F-FDG PET/CT double phase imaging in peritoneum metastasis localization of ascites patients were64.7%,85.7%,69.7%, and93.6%. Those of CT were47.1%,57.1%,49.4%, and78.1%. The former were higher than the latter (X2=4.29,4.20,7.56,4.51; P all<0.05).
The IRDI of primary tumors calculated by double phases PET/CT imaging was (45.0±63.1)%, those of peritoneum metastasis and benign lesions in peritoneum were (13.6±41.2)%and (-8.0±27.6)%. The latter was much lower than the two formers (t=3.71,2.22; Pall<0.05).
SUVmax>3.0in routine imaging and delay imaging, IRDI>15%in double phases imaging discriminated primary malignant tumor efficiently. SUVmax>2.0in delay imaging, IRDI>10%in double phases imaging discriminated peritoneum metastasis efficiently. The area under ROC curve of SUVmax in delay imaging was the larger than that of routine imaging and IRDI in double phases imaging.
Conclusion:
18F-FDG PET/CT double phase imaging promoted the diagnostic efficiency in primary tumor localization of ascites patients, which could demonstrate the continuous uptake of FDG in gastrointestinal primary tumor.
18F-FDG PET/CT double phase imaging accompany with the use of gastrointestinal tract contrast medium could successfully promote the diagnostic accuracy of peritoneum metastasis for ascites patients.
SUVmax>3.0in18F-FDG PET/CT routine or delay imaging or IRDI>15%could be considered as efficient index to promoted the diagnostic efficiency in primary tumor localization of ascites patients.
SUVmax measurement in'8F-FDG PET/CT double phase imaging is a good method to promote the diagnostic efficiency of peritoneum metastasis for ascites patients. SUVmax>2.0in delay imaging or IRDI>10%in double phases imaging were good index for peritoneum metastasis discriminated diagnosis.
Objective
With the greatly increased clinical application of positron emission tomography/computed tomography (PET/CT), the clinical value of F-deoxyglucose (18F-FDG) PET/CT has been highlighted in the diagnosis of malignant ascites. However, F-FDG is a non-specific tracer agent that can be absorbed by malignant tumor or a few benign diseases and sometimes even not be absorbed by some malignant tumors, consequently causing the problem of false-positive or false-negative in tumor localization by F-FDG PET/CT. To date, little information has been reported on ascites metabolism. Nevertheless, some information about FDG metabolism in ascites might be obtained through the measurement of the standard uptake value (SUV) of ascites and the observation of F-FDG PET/CT images. This study aimed to evaluate the role of ascites metabolism measurement in F-FDG PET/CT for auxiliary diagnosis and prognostic evaluation of malignant ascites.
Methods
This study reviewed all the medical records of55patients that underwent F-FDG PET/CT to determine the original cause of ascites. Among these55cases of ascites patients,36cases were malignant ascites and19cases were benign ascites. All patients underwent ascites CEA, ascites CA125, ascites CA199and ascites cytology examinations before or within two weeks after F-FDG PET/CT scans. The patients with negative results of ascites cytology were confirmed by clinical follow-up (including CT, MRI, supersound, abdominal speculum, repeated ascites cytology or histopathology). F-FDG PET/CT scan was performed on a PET/CT system. The scan field ranged from the head to middle of the thigh. Seven to8bed positions were usually required and the emission images were acquired for2.5min per bed position. Delayed imaging was performed50to90min after the first PET/CT scan according to the requirements of diagnosis.
The mean SUV (SUVmean) of ascites and liver were measured by elliptic region of interest (ROI) tools in fusion images. The SUV ratio of ascites and liver, denoted as T/NT, was calculated based on the SUVmean. The interpretation of18F-FDG PET/CT images was based on the consensus of two nuclear medicine physicians. Ascites metabolism measurement was based on the value of T/NT and the experience of nuclear medicine physicians. Ascites metabolism measurement was defined as positive if the ascites was found to increase the radioactivity uptake or the shapes of the liver and spleen were vague in maximum intensity projection (MIP) images. Otherwise, it was defined as negative. If definite lumps or abnormal metabolic foci were not found in F-FDG PET/CT images or they were found but interpreted as benign disease or no definite diagnosis was given, the18F-FDG PET/CT tumor localization was defined as negative. On the contrary, if definite abnormal metabolic foci or abnormal lumps were found and an interpretation of malignant tumor or metastasis was given, the F-FDG PET/CT tumor localization was defined as positive.Ascites cytology examination was performed before the first18F-FDG PET/CT or two weeks after. If malignant tumor cells were found, the result of ascites cytology examination was defined as positive. On the contrary, it was defined as negative.
Statistical analysis was performed by PASW Statistics18software and the result with P<0.05was considered as statistically significant. The sensitivity, specificity and accuracy were calculated and compared by X2-test or Fisher's analysis among F-FDG PET/CT ascites metabolism measurement, tumor localization, and ascites cytology examination. SUVmean of the ascites and liver were measured and the T/NT value was calculated and checked by t-test. The ROC curve was used to analyze the diagnostic efficiency of ascites T/NT, ascites CEA, ascites CA125, and ascites CA199. And the linear regression was used to analyze the relationship between ascites T/NT and the survival time of patients.
Results In cases of malignant ascites, the characteristics of immersed liver and spleen could be seen in those patients with widespread tiny metastasis in peritoneum in MIP images. In slice images of those patients, increased radioactive uptake was seen around peritoneum and intestinal canal, and the ascites metabolic level was lower in center and higher on verge. The sensitivity and accuracy of ascites metabolism measurement were higher than those of ascites cytology examination (X2=6.98,4.58; P all<0.05). The specificity of ascites metabolism measurement was higher than that of18F-FDG PET/CT tumor localization (X2=5.70, P<0.05).
The SUVmean of malignant ascites in routine imaging wasl.37±0.38. That of benign ascites was0.72±0.22. the former was higher than the latter (i=6.82, P<0.05). Based on the criteria of SUVmean>1.0, the sensitivity, specificity and accuracy were77.8%,84.2%, and81.8%respectively. The T/NT values of benign and malignant ascites were0.38±0.10and0.68±0.17, respectively, indicating that the latter was higher than the former (t=7.21, P<0.05). Nevertheless, the T/NT value of malignant ascites patients with positive results of ascites cytology examination was0.76±0.14, and that with negative results was0.62±0.16, indicating that the former was higher than the latter (t=2.80; P<0.05). Based on the criteria of T/NT>0.5, the sensitivity, specificity and accuracy were86.1%,78.9%, and83.6%respectively.
The area under ROC curve of T/NTmean in routine imaging, T/NTmean in delay imaging, SUVmean in routine imaging, SUVmea,in delay imaging, ascites CEA, ascites CA125and ascites CA199was0.837(P<0.01),0.871(P<0.01),0.805(P<0.01),0.836(P<0.01),0.707(P<0.05),0.561(P=0.463) and0.664(P<0.05), respectively. The area under ROC curve of SUVmean and T/NTmean were the larger than others. The area under ROC curve of ascites CA125was lower due to its abnormal increase in some benign ascites such as hepatic cirrhosis ascites and tuberculous ascites. There was a negative correlation between the survival of patients with malignant ascites and ascites T/NT (r=-0.647, P<0.01). The higher the ascites metabolism level was, the shorter survival time the patient would have.
Conclusion
1. In cases of malignant ascites, the characteristics of immersed liver and spleen could be seen in those patients with widespread tiny metastasis in peritoneum in18F-FDG PET/CT MIP images.Ascites metabolism measurement was good for differential diagnosis of malignant ascites, and has an important auxiliary diagnostic value for ascites patients.
2. The SUV ratio of ascites and liver in18F-FDG PET/CT imaging, denoted as T/NT, was helpful to determine the nature of ascites diagnosis. SUVmean>1.0and T/NTmean>0.5were good index for differential diagnosis of ascites. The T/NT and SUVmean of ascites were better than ascites CEA, ascites CA125, and ascites CA199in differential diagnosis of ascites.
3. There was a negative correlation between the survival of patients with malignant ascites and ascites T/NTmean, which may be a good index for prognostic evaluation of malignant ascites
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6. Kushraj T, Chatra L, Shenai P, Rao PK. Bone invasion in oral cancer patients:a comparison between Orthopantamograph, conventional computed tomography, and single positron emission computed tomography. J Cancer Res Ther.2011,7:438-841.
7. Manohar K, Mittal BR, Kashyap R, Bhattacharya A, Kakkar N, Mete UK. F-18 fluorodeoxy glucose positron emission tomography/computed tomography findings in a rare case of penile leiomyosarcoma. J Clin Imaging Sci.2011,1:5-8.
8. Zhang M, Jiang X, Zhang M, et al. The Role of 18F-FDG PET/CT in the evaluation of Ascites of Undetermined Origin. J Nucl Med,2009,50:506-512.
9. Kondo M, Nagano H, Sakon M, Hayashi S, Okami J, Dono K, Umeshita K, Nakamori S, Wakasa K, Monden M. The effect of beta-blocker on intractable ascites in cirrhotic patients undergoing hepatectomy for hepatocellular carcinoma. Hepatogastroenterology.2003,50:504-506.
10. Norsa' adah B, Nur-Zafira A, Knight A. Pancreatic cancer in Universiti Sains Malaysia Hospital:a retrospective review of years 2001-2008. Asian Pac J Cancer Prev.2012,13:2857-2860.
11. Meunier L, Puiffe ML, Le Page C, Filali-Mouhim A, Chevrette M, Tonin PN, Provencher DM, Mes-Masson AM.Effect of ovarian cancer ascites on cell migration and gene expression in an epithelial ovarian cancer in vitro model. Transl Oncol.2010, 3:230-238.
12. Shin H, Kim MH, Lee SJ, Lee KH, Kim MJ, Kim JS, Cho JW. Decreased Metabolism in the Cerebral Cortex in Early-Stage Huntington's Disease:A Possible Biomarker of Disease Progression? J Clin Neurol.2013,9:21-25.
13. Zhuang H, Pourdehnad M, Lambright ES, et al. Dual time point 18F-FDG PET imaging for differentiating malignant from inflammatory processes. J Nucl Med 2001, 42:1412-1417.
14、Yamada S, Kubota K, Kubota R, et al. High accumulation of fluorine-18-fluorodeoxyglucose in turpentine-induced in flammatory tissue. J Nucl Med,1995, 36:1301-1306.
15. Lodge MA, Lucas JD, Marsden PK, Cronin BF, O'Doherty MJ, Smith MA. A PET study of 18FDG uptake in soft tissue masses. Eur J Nucl Med.1999,26:22-30.
16.孟德刚,孙晓光,黄钢,刘建军,宋少莉,万良荣.口服不同对比剂对PET／CT胃肠道充盈及FDG摄取影响.中华核医学杂志,2010,30：272-275.
17. Saada E, Follana P, Peyrade F, et al. Pathogenesis and management of refractory malignant ascites. Bull Cancer,2011,98:679-687.
18.付占立,王荣福18F-FDG PET显像的定量及半定量分析.中华核医学杂志,2004,24：313-317.
19. Crippa F, Gavazzi C, Bozzetti F, Chiesa C, Pascali C, Bogni A, De Sanctis V, Decise D, Schiavini M, Cucchetti G, Bombardieri E.The influence of blood glucose levels on [18F] fluorodeoxyglucose (FDG) uptake in cancer:a PET study in liver metastases from colorectal carcinomas. Tumori.1997,83:748-752.
20. Diederichs CG, Staib L, Glatting G, Beger HG, Reske SN.FDG PET:elevated plasma glucose reduces both uptake and detection rate of pancreatic malignancies. J Nucl Med.1998,39:1030-1033.
21. Delbeke D, Martin WH, Sandler MP, Chapman WC, Wright JK Jr, Pinson CW.Evaluation of benign vs malignant hepatic lesions with positron emission tomography. Arch Surg.1998,133:510-516.
I. Zhang M, Jiang X, Zhang M, et al. The Role of 18F-FDG PET/CT in the evaluation of Ascites of Undetermined Origin. J Nucl Med,2009,50:506-512.
2.王晓燕,张祥松,陈志丰,等.18F-FDG PET/CT显像诊断腹膜转移瘤的临床价值.中华核医学杂志,2010,30：98-100.
3.王丽娟,王全师,陈萍,吴湖炳18F-FDG PET/CT显像鉴别腹腔积液性质的价值.中华核医学杂志,2012,32：105-110.
4. Meller J, Sahlmann CO, Scheel AK.18F-FDG PET and PET/CT in fever of unknown origin. J Nucl Med,2007,48:35-45.
5. Shin JA, Park JW, An M, et al. Diagnostic accuracy of 18F-FDG positron emission tomography for evaluation of hepatocellular carcinoma. Korean J Hepatol,2006,12: 546-552.
6.李松年.现代全身CT诊断学.北京：中国医药科技出版社,2001：1053-1059.
7. Saada E, Follana P, Peyrade F, et al. Pathogenesis and management of refractory malignant ascites. Bull Cancer,2011,98:679-687.
8. Kleinberg L, Holth A, Fridman E, et al. The diagnostic role of claudins in serous effusions. Am J Clin Pathol,2007; 127:928-937.
9. Jung M, Jeung HC, Lee SS, et al.The clinical significance of ascitic fluid CEA in advanced gastric cancer with ascites. J Cancer Res Clin Oncol.2010; 136:517-526.
10. Leung TK, Lee CM, Wang FC, et al. Difficulty with diagnosis of malignant pancreatic neoplasms coexisting with chronic pancreatitis. World J Gastroenterol. 2005; 11:5075-5078.
11. Gupta S, Maheshwari A, Wuntkal R, et al. Diagnostic dilemma in an elderly woman with intractable ascites and elevated CA-125 level. Assoc Physicians India. 2006; 54:655-656.
12. Lockhart CJ, McVeigh GE, Harbinson MT. Elevated CA 125 and ascites:not always malignancy. Ir J Med Sci.2008; 177:63-66.
13. Honda K, Hayashida Y, Umaki T, et al. Possible detection of pancreatic cancer by plasma protein profiling. Cancer Res.2005; 65:10613-10622.
1. Yang ZY, Hu SL, Shi W, Zhu BL, Xu JY, Zhang YJ. The clinical value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in postoperative patients with gastrointestinal mucinous adenocarcinoma. Nucl Med Commun.2011; 32:1018-1025.
2. Zhang M, Jiang X, Zhang M, Xu H, Zhai G, Li B. The Role of 18F-FDG PET-CT in the evaluation of Ascites of Undetermined Origin. J Nucl Med.2009; 50:506-512.
3. Bilici A, Ustaalioglu BB, Seker M, Kefeli U, Canpolat N, Tekinsoy B, et al. The role of F-FDG PET-CT in the assessment of suspected recurrent gastric cancer after initial surgical resection:can the results of FDG PET-CT influence patients' treatment decision making? Eur J Nucl Med Mol Imaging.2011; 38:64-73.
4. Meller J, Sahlmann CO, Scheel AK.18F-FDG PET and PET-CT in fever of unknown origin. J Nucl Med,2007,48:35-45.
5. Shin JA, Park JW, An M, Choi JI, Kim SH, Kim SK, et al. Diagnostic accuracy of 18F-FDG positron emission tomography for evaluation of hepatocellular carcinoma. Korean J Hepatol,2006,12:546-552.
6. Passebosc-Faure K, Li G, Lambert C, Cottier M, Gentil-Perret A, Fournel P, et al. Evaluation of a panel of molecular markers for the diagnosis of malignant serous effusions. Clin Cancer Res.2005; 11:6862-6867.
7. Wu M, Yuan S, Szporn AH, Gan L, Shtilbans V, Burstein DE. Immunocytochemical detection of XIAP in body cavity effusions and washes. Clin Cancer Res.2005; 11:113-122.
8. Wang E, Ngalame Y, Panelli MC, Nguyen-Jackson H, Deavers M, Mueller P, et al. Peritoneal and subperitoneal stroma may facilitate regional spread of ovarian cancer. Mod Pathol.2005; 18:1618-1622.
9. Saada E, Follana P, Peyrade F, Mari V, Francois E. Pathogenesis and management of refractory malignant ascites. Bull Cancer,2011,98:679-687.
10. Kleinberg L, Holth A, Fridman E, Schwartz I, Shih IeM, Davidson B. The diagnostic role of claudins in serous effusions. Am J Clin Pathol.2007; 127: 928-937.
11. Aukema TS, Vogel WV, Hoefnagel CA, et al. Prevention of brown adipose tissue activation in 18F-FDG PET-CT of breast cancer patients receiving neoadjuvant systemic therapy. J Nucl Med Technol.2010,38:24-27.
12. Kim HW, Choi BW, Won KS, et al. Cervical tuberculous lymphadenitis mimicking distant lymph node metastasis on F-FDG PET-CT in a patient with gastric carcinoid tumor. Clin Nucl Med.2009,34:946-947.
13. Jung M, Jeung HC, Lee SS, Park JY, Hong S, Lee SH, et al. The clinical significance of ascitic fluid CEA in advanced gastric cancer with ascites. J Cancer Res Clin Oncol.2010; 136:517-526.
14. Leung TK, Lee CM, Wang FC, Chen HC, Wang HJ. Difficulty with diagnosis of malignant pancreatic neoplasms coexisting with chronic pancreatitis. World J Gastroenterol.2005; 11:5075-5078.
15. Gupta S, Maheshwari A, Wuntkal R, Mazid T, Tongaonkar HB. Diagnostic dilemma in an elderly woman with intractable ascites and elevated CA125 level. Assoc Physicians India.2006; 54:655-656.
16. Lockhart CJ, McVeigh GE, Harbinson MT. Elevated CA125 and ascites:not always malignancy. Ir J Med Sci.2008; 177:63-66.
17. Honda K, Hayashida Y, Umaki T, Okusaka T, Kosuge T, Kikuchi S, et al. Possible detection of pancreatic cancer by plasma protein profiling. Cancer Res.2005; 65: 10613-10622.
18. Garrison RN, Kaelin LD, Galloway RH, Heuser LS. Malignant ascites:clinical and experimental observations. Ann Surg.1986; 203:644—651.
19. Lane D, Robert V, Grondin R, Rancourt C, Piche A. Malignant ascites protect against TRAIL-induced apoptosis by activating the PI3K/Akt in human ovarian carcinoma cells. Int J Cancer.2007; 121:1227-1237.
20. Shahzad MM, Arevalo JM, Armaiz-Pena GN, Lu C, Stone RL, Moreno-Smith M, et al. Stress effects on FosB-and interleukin-8(IL8)-driven ovarian cancer growth and metastasis. J Biol Chem.2010; 285:35462-35470.
21. Lo CW, Chen MW, Hsiao M, Wang S, Chen CA, Hsiao SM, et al. IL-6 trans-signaling in formation and progression of malignant ascites in ovarian cancer. Cancer Res.2011; 71:424-434.
2. Kuralay F, Tokgoz Z, Comlekci A.Diagnostic usefulness of tumour marker levels in pleural effusions of malignant and benign origin.Clin Chim Acta.2000,300:43-55.
3. Kleinberg L, Holth A, Fridman E, Schwartz I, Shih IeM, Davidson B. The diagnostic role of claudins in serous effusions. Am J Clin Pathol.2007,127:928-937.
4.克力木,张成,陈勇,等.腹腔镜探查诊断不明原因腹腔积液价值探讨.中华临床医师杂志,2010,4：2542-2545.
5.周东雷,郑成竹,胡旭光,等.腹腔镜对不明原因腹腔积液诊断价值研究.中国实用外科杂志,2007,7：627-629.
6. Gulyas M, Kaposi AD, Elek G, Szollar LG, Hjerpe A. Value of carcinoembryonic antigen (CEA) and cholesterol assays of ascitic fluid in cases of inconclusive cytology. J Clin Pathol.2001,54:831-835.
7. Trape J, Molina R, Sant F. Clinical evaluation of the simultaneous determination of tumor markers in fluid and serum and their ratio in the differential diagnosis of serous effusions. Tumour Biol.2004,25:276-281.
8. Li HY, Zhou SJ, Li M, Xiong D, Singh A, Guo QX, Liu CA, Gong JP. Diagnosis and cure experience of hepatolithiasis-associated intrahepatic cholangiocarcinoma in 66 patients. Asian Pac J Cancer Prev.2012,13:725-729.
9. Bouzari Z, Yazdani S, Ahmadi MH, Barat S, Kelagar ZS, Kutenaie MJ, Abbaszade N, Khajat F. Comparison of three malignancy risk indices and CA-125 in the preoperative evaluation of patients with pelvic masses. BMC Res Notes.2011,20; 42-46.
10. Mittal P, Gupta R, Mittal G, Kalia V. Association between portal vein color Doppler findings and the severity of disease in cirrhotic patients with portal hypertension. Iran J Radiol.2011,8:211-217.
11. Narahara Y, Kanazawa H, Fukuda T, Matsushita Y, Harimoto H, Kidokoro H, Katakura T, Atsukawa M, Taki Y, Kimura Y, Nakatsuka K, Sakamoto C. Transjugular intrahepatic portosystemic shunt versus paracentesis plus albumin in patients with refractory ascites who have good hepatic and renal function:a prospective randomized trial. J Gastroenterol.2011,46:78-85.
12. Ohira G, Shuto K, Kono T, Tohma T, Gunji H, Narushima K, Imanishi S, Fujishiro T, Tochigi T, Hanaoka T, Miyauchi H, Hanari N, Matsubara H, Yanagawa N. Utility of arterial phase of dynamic CT for detection of intestinal ischemia associated with strangulation ileus. World J Radiol.2012,28; 4:450-454.
13. Hommel C, Knoedler M, Bojarski C, Schumann M, Epple HJ, Zeitz M, Daum S. Diffuse gastric cancer with peritoneal carcinomatosis can mimic Crohn's disease. Case Rep Gastroenterol.2012,6:695-703.
14. de Bree E, Koops W, Kroger R, van Ruth S, Witkamp AJ, Zoetmulder FA. Peritoneal carcinomatosis from colorectal or appendiceal origin:correlation of preoperative CT with intraoperative findings and evaluation of interobserver agreement. J Surg Oncol.2004,86:64-73.
15. Sugiyama A, Urushihara N, Fukumoto K, Fukuzawa H, Nagae H, Watanabe K, Mitsunaga M, Hasegawa S, Koyama M. Ovarian fibroma with marked ascites and elevated serum levels of CA-125 in a young girl. J Pediatr Surg.2011,46:1001-1004.
16. ZHU AN, LI JD, FENG YL, XU MM, ZHUANG Y. Clinical analysis of 12 cases of ovarian carcinosarcoma. Nan Fang Yi Ke Da Xue Xue Bao.2011,31:518-521.
17. Zhang M, Jiang X, Zhang M, Xu H, Zhai G, Li B. The Role of F-FDG PET/CT in the evaluation of Ascites of Undetermined Origin. J Nucl Med.2009,50:506-512.
18.杨秋蒙,郑成竹,胡旭光,等.PET-CT诊断胃癌腹膜转移的临床价值.上海 交通大学学报(医学版).2007,27：573-576.
19. Turlakow A, Yeung HW. Salmon AS, Macapinlac HA, Larson SM. Peritoneal carcinomatosis:role of F-FDG PET. J Nucl Med.2003,44:1407-1412.
20.王丽娟,王全师,陈萍,等F-FDG PET-CT显像鉴别腹腔积液性质的价值.中华核医学与分子影像杂志,2004,32：105-110.
21. Yang QM, Bando E, Kawamura T, Tsukiyama G, Nemoto M, Yonemura Y, Furukawa H.The diagnostic value of PET-CT for peritoneal dissemination of abdominal malignancies. Gan To Kagaku Ryoho.2006,33:1817-1821.
1. Mittal P, Gupta R, Mittal G, Kalia V. Association between portal vein color Doppler findings and the severity of disease in cirrhotic patients with portal hypertension. Iran J Radiol.2011,8:211-217.
2. Hommel C, Knoedler M, Bojarski C, Schumann M, Epple HJ, Zeitz M, Daum S. Diffuse gastric cancer with peritoneal carcinomatosis can mimic Crohn's disease. Case Rep Gastroenterol.2012,6:695-703.
3. Cerwenka H. Neuroendocrine liver metastases:contributions of endoscopy and surgery to primary tumor search. World J Gastroenterol.2012,18:1009-1014.
4. Devillier R, Coso D, Castagna L, Brenot Rossi I, Anastasia A, Chiti A, Ivanov V, Schiano JM, Santoro A, Chabannon C, Balzarotti M, Blaise D, Bouabdallah R. Positron emission tomography response at the time of autologous stem cell transplantation predicts outcome of patients with relapsed and/or refractory Hodgkin's lymphoma responding to prIRDI salvage therapy. Haematologica.2012, 97:1073-1079.
5. Bipat S, Niekel MC, Comans EF, Nio CY, Bemelman WA, Verhoef C, Stoker J. Imaging modalities for the staging of patients with colorectal cancer. Neth J Med. 2012,70:26-34.
6. Kushraj T, Chatra L, Shenai P, Rao PK. Bone invasion in oral cancer patients:a comparison between Orthopantamograph, conventional computed tomography, and single positron emission computed tomography. J Cancer Res Ther.2011,7:438-841.
7. Manohar K, Mittal BR, Kashyap R, Bhattacharya A, Kakkar N, Mete UK. F-18 fluorodeoxy glucose positron emission tomography/computed tomography findings in a rare case of penile leiomyosarcoma. J Clin Imaging Sci.2011,1:5-8.
8. Zhang M, Jiang X, Zhang M, et al. The Role of 18F-FDG PET/CT in the evaluation of Ascites of Undetermined Origin. J Nucl Med,2009,50:506-512.
9. Kondo M, Nagano H, Sakon M, Hayashi S, Okami J, Dono K, Umeshita K, Nakamori S, Wakasa K, Monden M. The effect of beta-blocker on intractable ascites in cirrhotic patients undergoing hepatectomy for hepatocellular carcinoma. Hepatogastroenterology.2003,50:504-506.
10. Norsa' adah B, Nur-Zafira A, Knight A. Pancreatic cancer in Universiti Sains Malaysia Hospital:a retrospective review of years 2001-2008. Asian Pac J Cancer Prev.2012,13:2857-2860.
11. Meunier L, Puiffe ML, Le Page C, Filali-Mouhim A, Chevrette M, Tonin PN, Provencher DM, Mes-Masson AM.Effect of ovarian cancer ascites on cell migration and gene expression in an epithelial ovarian cancer in vitro model. Transl Oncol.2010, 3:230-238.
12. Shin H, Kim MH, Lee SJ, Lee KH, Kim MJ, Kim JS, Cho JW. Decreased Metabolism in the Cerebral Cortex in Early-Stage Huntington's Disease:A Possible Biomarker of Disease Progression? J Clin Neurol.2013,9:21-25.
13. Zhuang H, Pourdehnad M, Lambright ES, et al. Dual time point 18F-FDG PET imaging for differentiating malignant from inflammatory processes. J Nucl Med 2001, 42:1412-1417.
14、Yamada S, Kubota K, Kubota R, et al. High accumulation of fluorine-18-fluorodeoxyglucose in turpentine-induced in flammatory tissue. J Nucl Med,1995, 36:1301-1306.
15. Lodge MA, Lucas JD, Marsden PK, Cronin BF, O'Doherty MJ, Smith MA. A PET study of 18FDG uptake in soft tissue masses. Eur J Nucl Med.1999,26:22-30.
16.孟德刚,孙晓光,黄钢,刘建军,宋少莉,万良荣.口服不同对比剂对PET／CT胃肠道充盈及FDG摄取影响.中华核医学杂志,2010,30：272-275.
17. Saada E, Follana P, Peyrade F, et al. Pathogenesis and management of refractory malignant ascites. Bull Cancer,2011,98:679-687.
18.付占立,王荣福18F-FDG PET显像的定量及半定量分析.中华核医学杂志,2004,24：313-317.
19. Crippa F, Gavazzi C, Bozzetti F, Chiesa C, Pascali C, Bogni A, De Sanctis V, Decise D, Schiavini M, Cucchetti G, Bombardieri E.The influence of blood glucose levels on [18F] fluorodeoxyglucose (FDG) uptake in cancer:a PET study in liver metastases from colorectal carcinomas. Tumori.1997,83:748-752.
20. Diederichs CG, Staib L, Glatting G, Beger HG, Reske SN.FDG PET:elevated plasma glucose reduces both uptake and detection rate of pancreatic malignancies. J Nucl Med.1998,39:1030-1033.
21. Delbeke D, Martin WH, Sandler MP, Chapman WC, Wright JK Jr, Pinson CW.Evaluation of benign vs malignant hepatic lesions with positron emission tomography. Arch Surg.1998,133:510-516.
I. Zhang M, Jiang X, Zhang M, et al. The Role of 18F-FDG PET/CT in the evaluation of Ascites of Undetermined Origin. J Nucl Med,2009,50:506-512.
2.王晓燕,张祥松,陈志丰,等.18F-FDG PET/CT显像诊断腹膜转移瘤的临床价值.中华核医学杂志,2010,30：98-100.
3.王丽娟,王全师,陈萍,吴湖炳18F-FDG PET/CT显像鉴别腹腔积液性质的价值.中华核医学杂志,2012,32：105-110.
4. Meller J, Sahlmann CO, Scheel AK.18F-FDG PET and PET/CT in fever of unknown origin. J Nucl Med,2007,48:35-45.
5. Shin JA, Park JW, An M, et al. Diagnostic accuracy of 18F-FDG positron emission tomography for evaluation of hepatocellular carcinoma. Korean J Hepatol,2006,12: 546-552.
6.李松年.现代全身CT诊断学.北京：中国医药科技出版社,2001：1053-1059.
7. Saada E, Follana P, Peyrade F, et al. Pathogenesis and management of refractory malignant ascites. Bull Cancer,2011,98:679-687.
8. Kleinberg L, Holth A, Fridman E, et al. The diagnostic role of claudins in serous effusions. Am J Clin Pathol,2007; 127:928-937.
9. Jung M, Jeung HC, Lee SS, et al.The clinical significance of ascitic fluid CEA in advanced gastric cancer with ascites. J Cancer Res Clin Oncol.2010; 136:517-526.
10. Leung TK, Lee CM, Wang FC, et al. Difficulty with diagnosis of malignant pancreatic neoplasms coexisting with chronic pancreatitis. World J Gastroenterol. 2005; 11:5075-5078.
11. Gupta S, Maheshwari A, Wuntkal R, et al. Diagnostic dilemma in an elderly woman with intractable ascites and elevated CA-125 level. Assoc Physicians India. 2006; 54:655-656.
12. Lockhart CJ, McVeigh GE, Harbinson MT. Elevated CA 125 and ascites:not always malignancy. Ir J Med Sci.2008; 177:63-66.
13. Honda K, Hayashida Y, Umaki T, et al. Possible detection of pancreatic cancer by plasma protein profiling. Cancer Res.2005; 65:10613-10622.
1. Yang ZY, Hu SL, Shi W, Zhu BL, Xu JY, Zhang YJ. The clinical value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in postoperative patients with gastrointestinal mucinous adenocarcinoma. Nucl Med Commun.2011; 32:1018-1025.
2. Zhang M, Jiang X, Zhang M, Xu H, Zhai G, Li B. The Role of 18F-FDG PET-CT in the evaluation of Ascites of Undetermined Origin. J Nucl Med.2009; 50:506-512.
3. Bilici A, Ustaalioglu BB, Seker M, Kefeli U, Canpolat N, Tekinsoy B, et al. The role of F-FDG PET-CT in the assessment of suspected recurrent gastric cancer after initial surgical resection:can the results of FDG PET-CT influence patients' treatment decision making? Eur J Nucl Med Mol Imaging.2011; 38:64-73.
4. Meller J, Sahlmann CO, Scheel AK.18F-FDG PET and PET-CT in fever of unknown origin. J Nucl Med,2007,48:35-45.
5. Shin JA, Park JW, An M, Choi JI, Kim SH, Kim SK, et al. Diagnostic accuracy of 18F-FDG positron emission tomography for evaluation of hepatocellular carcinoma. Korean J Hepatol,2006,12:546-552.
6. Passebosc-Faure K, Li G, Lambert C, Cottier M, Gentil-Perret A, Fournel P, et al. Evaluation of a panel of molecular markers for the diagnosis of malignant serous effusions. Clin Cancer Res.2005; 11:6862-6867.
7. Wu M, Yuan S, Szporn AH, Gan L, Shtilbans V, Burstein DE. Immunocytochemical detection of XIAP in body cavity effusions and washes. Clin Cancer Res.2005; 11:113-122.
8. Wang E, Ngalame Y, Panelli MC, Nguyen-Jackson H, Deavers M, Mueller P, et al. Peritoneal and subperitoneal stroma may facilitate regional spread of ovarian cancer. Mod Pathol.2005; 18:1618-1622.
9. Saada E, Follana P, Peyrade F, Mari V, Francois E. Pathogenesis and management of refractory malignant ascites. Bull Cancer,2011,98:679-687.
10. Kleinberg L, Holth A, Fridman E, Schwartz I, Shih IeM, Davidson B. The diagnostic role of claudins in serous effusions. Am J Clin Pathol.2007; 127: 928-937.
11. Aukema TS, Vogel WV, Hoefnagel CA, et al. Prevention of brown adipose tissue activation in 18F-FDG PET-CT of breast cancer patients receiving neoadjuvant systemic therapy. J Nucl Med Technol.2010,38:24-27.
12. Kim HW, Choi BW, Won KS, et al. Cervical tuberculous lymphadenitis mimicking distant lymph node metastasis on F-FDG PET-CT in a patient with gastric carcinoid tumor. Clin Nucl Med.2009,34:946-947.
13. Jung M, Jeung HC, Lee SS, Park JY, Hong S, Lee SH, et al. The clinical significance of ascitic fluid CEA in advanced gastric cancer with ascites. J Cancer Res Clin Oncol.2010; 136:517-526.
14. Leung TK, Lee CM, Wang FC, Chen HC, Wang HJ. Difficulty with diagnosis of malignant pancreatic neoplasms coexisting with chronic pancreatitis. World J Gastroenterol.2005; 11:5075-5078.
15. Gupta S, Maheshwari A, Wuntkal R, Mazid T, Tongaonkar HB. Diagnostic dilemma in an elderly woman with intractable ascites and elevated CA125 level. Assoc Physicians India.2006; 54:655-656.
16. Lockhart CJ, McVeigh GE, Harbinson MT. Elevated CA125 and ascites:not always malignancy. Ir J Med Sci.2008; 177:63-66.
17. Honda K, Hayashida Y, Umaki T, Okusaka T, Kosuge T, Kikuchi S, et al. Possible detection of pancreatic cancer by plasma protein profiling. Cancer Res.2005; 65: 10613-10622.
18. Garrison RN, Kaelin LD, Galloway RH, Heuser LS. Malignant ascites:clinical and experimental observations. Ann Surg.1986; 203:644—651.
19. Lane D, Robert V, Grondin R, Rancourt C, Piche A. Malignant ascites protect against TRAIL-induced apoptosis by activating the PI3K/Akt in human ovarian carcinoma cells. Int J Cancer.2007; 121:1227-1237.
20. Shahzad MM, Arevalo JM, Armaiz-Pena GN, Lu C, Stone RL, Moreno-Smith M, et al. Stress effects on FosB-and interleukin-8(IL8)-driven ovarian cancer growth and metastasis. J Biol Chem.2010; 285:35462-35470.
21. Lo CW, Chen MW, Hsiao M, Wang S, Chen CA, Hsiao SM, et al. IL-6 trans-signaling in formation and progression of malignant ascites in ovarian cancer. Cancer Res.2011; 71:424-434.