18F-FDG PET/CT在恶性肿瘤伽玛刀治疗后复查中的应用

目的探讨18F-脱氧葡萄糖(FDG)PET/CT在恶性肿瘤伽玛刀治疗后疗效评价中的应用价值.方法对18例体部恶性肿瘤伽玛刀治疗前后行PET/CT检查的患者资料进行分析,观察病灶的CT及PET影像学表现,进行治疗前后疗效对比分析.结果治疗有效的CT检查表现为病灶缩小、纤维化,大病灶中心低密度液化坏死区,有斑片状钙化.CT检查疗效分析结果治疗后18例中完全缓解(CR)3例(16.7%),部分缓解(PR)10例(55.6%),无变化(NC)2例(11.1%),进展(PD)3例(16.7%),总缓解率(CR+PR)为72.2%.共34个病灶进行治疗,治疗后有效病灶PET显像表现为放射性浓聚程度较轻,较模糊,边缘欠清,分布不均,坏死区见放射性缺损.PET显像疗效分析结果治疗后18例中CR4例(22.2%),PR 8例(44.4%),NC 1例(5.6%),PD 5例(27.8%),CR+PR为66.7%.治疗后标准摄取值(SUV)改变的病灶为100%(34/34例),其中SUV下降病灶占85.3%(29/34个),SUV增加病灶占14.7%(5/34个).SUV变化率＞50%的病灶占44.1%(15/34个).34个病灶治疗前后SUV分别为6.33±2.62、3.88±1.82,两者比较差异有显著性(t=5.580,P＜0.001).结论 PET/CT对伽玛刀治疗后肿瘤局部控制率的评价有重要价值.PET显示肿瘤残余及复发明显优于CT.     

口腔鳞癌的18F-FDG PET/CT的影像学表现以及与CT平扫的比较研究

目的 评价18F-FDG PET-CT检查在口腔鳞癌患者的诊断和淋巴结转移灶发现的价值.方法 回顾性地分析了18例口腔癌(其中包括16例舌癌和2例口底癌患者)的临床和18F-FDG PET-CT影像学表现及CT平扫的影像学资料.结果 (1)原发病灶的发现全部病例中有5例患者是由PET/CT检查首次发现口腔癌的;PET/CT对原发部位肿瘤病变显示的灵敏度100%(15/15),特异性100%(3/3);CT对原发病灶显示的灵敏度为73.3%(11/15),特异性为66.7%(2/3).(2)18例口腔癌患者中PET/CT诊断颈部淋巴结转移灶共26个,大小介于0.8～1.5 cm之间,标准摄取值(SUV)介于2.5～3.2之间;其中仅有5个淋巴结经病理组织活检证实为淋巴结转移灶.(3)通过PET/CT检查新发现全身其他部位的侵犯和远处转移性病灶8个.结论 PET/CT对口腔鳞癌原发灶诊断的灵敏度和特异性均比CT平扫高;全身PET/CT扫描对舌癌和口底癌的临床分期、术后复发的判定更具价值.     

结核病18F-FDG PET图像表现的多样性

目的总结结核病18F-脱氧葡萄糖(FDG) PET显像的影像学特征.方法回顾性分析26例结核病患者的18F-FDG PET图像,其中21例由组织病理学检查结果证实,余5例据临床资料诊断.所有患者在注射18F-FDG 60～90 min后进行衰减校正全身PET显像.其中14例患者同时行早期(40～65 min)和延迟(1.5～2.5 h)双时相检查.图像判读包括目测法和标准摄取值(SUV)半定量分析.双时相显像计算SUV变化率[ΔSUV(%)].结果 26例结核病患者中22例可见18F-FDG摄取,肺结核摄取18F-FDG有4种基本类型肺结节局限性18F-FDG浓聚(9例);肺内病灶同时伴有肺门或纵隔淋巴结浓聚(5例);肺伴有锁骨上和(或)腹腔淋巴结异常浓聚(3例);广泛胸膜异常浓聚(2例).平均SUVmax为3.64±2.58(1.4～7.6 ).延迟相SUV与早期相比较随时间延长而增加[(34.62±7.25)%].3例肺外结核18F-FDG PET显像呈阳性.4例陈旧性肺结核患者在CT所示结节部位未见18F-FDG摄取.结论结核病18F-FDG摄取可作为结核活动性的一个标志,其18F-FDG PET表现呈多样性.阳性18F-FDG摄取在肺部结节良恶性鉴别诊断时应慎重,特别是多发高代谢病灶背景不清晰时.背景不清晰的病灶结合结核菌素试验阳性,应考虑结核可能.     

结核病18F-FDG PET图像表现的多样性

目的总结结核病18F-脱氧葡萄糖(FDG) PET显像的影像学特征.方法回顾性分析26例结核病患者的18F-FDG PET图像,其中21例由组织病理学检查结果证实,余5例据临床资料诊断.所有患者在注射18F-FDG 60～90 min后进行衰减校正全身PET显像.其中14例患者同时行早期(40～65 min)和延迟(1.5～2.5 h)双时相检查.图像判读包括目测法和标准摄取值(SUV)半定量分析.双时相显像计算SUV变化率[ΔSUV(%)].结果 26例结核病患者中22例可见18F-FDG摄取,肺结核摄取18F-FDG有4种基本类型:肺结节局限性18F-FDG浓聚(9例);肺内病灶同时伴有肺门或纵隔淋巴结浓聚(5例);肺伴有锁骨上和(或)腹腔淋巴结异常浓聚(3例);广泛胸膜异常浓聚(2例).平均SUVmax为3.64±2.58(1.4～7.6 ).延迟相SUV与早期相比较随时间延长而增加[(34.62±7.25)%].3例肺外结核18F-FDG PET显像呈阳性.4例陈旧性肺结核患者在CT所示结节部位未见18F-FDG摄取.结论结核病18F-FDG摄取可作为结核活动性的一个标志,其18F-FDG PET表现呈多样性.阳性18F-FDG摄取在肺部结节良恶性鉴别诊断时应慎重,特别是多发高代谢病灶背景不清晰时.背景不清晰的病灶结合结核菌素试验阳性,应考虑结核可能.     

18F-FDG PET显像在胃恶性肿瘤治疗后随访中的应用

目的评价18F-脱氧葡萄糖(FDG)PET显像在胃恶性肿瘤治疗后随访中的价值.方法回顾性分析1999年1月～2004年11月做18F-FDG PET检查的52例经病理检查确诊为胃恶性肿瘤的PET图像,其中49例患者有同期CT检查结果.PET显像结果均由病理或临床及其他影像学检查随访证实.结果①23例患者治疗后胃局部18F-FDG摄取增高,其中9例证实有肿瘤残余或局部复发,标准摄取值(SUV)为4.24±2.98.14例为生理性摄取或胃炎、吻合口炎、胃动力异常等良性摄取,SUV 2.72±0.62.两组比较差异有显著性(t=1.87,P＜0.05).②对转移灶的检出,18F-FDG PET显像和CT检查的灵敏度分别为90.0%(27/30例)、50.0%(15/30例),两者差异有显著性(X2=11.43,P＜0.005).PET显像9例与CT检查结果相符;6例PET发现的病灶多于CT;10例PET发现转移灶而CT未见异常,其中2例B超检查阳性而CT检查阴性,PET显像证实了B超所见;2例PET否定了CT提示的转移灶,但发现其他部位转移.5例仅血清肿瘤标志物水平升高,其他检查阴性,而PET显像发现转移灶.25例PET显像未发现转移灶者中有3例假阴性.结论18F-FDGPET显像对胃肿瘤治疗后残余或复发及转移灶检出率高于其他影像学检查,但特异性差.     

氩氦刀冷冻消融术后PET/CT的标准化摄取值与肿瘤残存的相关性研究

目的 探讨肿瘤氩氦刀冷冻消融术后18F-FDG PET/CT显像的标准化摄取值(SUV)与肿瘤残存的相关性.方法 收集2008年3月至2015年12月40例肝、肺恶性肿瘤氩氦刀冷冻消融治疗患者的临床资料,治疗前后行18F-FDG PET/CT检查,记录每例患者的SUV值,并根据病理和临床随访进行数据分析.结果 40例患者共42个治疗灶,38个病灶术后发现放射性核素浓聚,经影像学随访和病理检查证实16个病灶有肿瘤残存,22个病灶为炎性反应.肿瘤残存病灶的SUV值明显高于炎性反应(6.13±1.21对2.64±0.96,P＜0.05),低SUV值组具有较低的复发率(P=0.020)和较高的生存率(P=0.039).低SUV值组的肿瘤残存率明显低于高SUV值组(x2=14.994,P=0.000 2).结论 18F-FDG PET/CT显像在冷冻消融术后边缘残余病灶的及时检出方面具有独特价值,为判断消融效果和进一步的临床治疗提供依据.     

胸腔积液的18F-FDGPET/CT病因诊断

目的:不明原因胸腔积液病因的诊断是临床治疗的前提,本研究探讨18F-脱氧葡萄糖(FDG)PET/CT显像在病因诊断中的价值.方法:对43例原冈未明的胸腔积液患者行18F-FDG PET/CT全身显像.结合PET和CT图像进行综合判断,PET结果的判断采用目测法和标准摄取值(SUV)测定.结果:恶性胸腔积液26例,良性17例(结核性7例,炎性6例,心源性4例).26例恶性者中,21例PET/CT检出原发病灶,5例未找到原发病灶;6例炎性者PET/CT诊断明确;7例结核性中5例经PET/CT检查诊断明确,另2例误诊为恶性;心源性4例PET/CT检查阴性.18F-FDG PET/CT对不明原因胸腔积液病因诊断的灵敏度80.8%(21/26),特异性为88.2%(15/17),阳性预测值为91.3%(21/23),阴性预测值为75.0%(15/20).结论:18F-FDG PET/CT可用于不明原因胸腔积液的病因诊断,并有较高的诊断准确率.     

18F-FDG PET显像对胰腺良恶性病变鉴别诊断的作用

目的探讨18F-脱氧葡萄糖(FDG) PET显像对胰腺良恶性病变鉴别诊断的价值.方法临床疑胰腺病变患者30例,其中胰腺恶性肿瘤20例胰腺癌15例,胰腺癌切除术后复发3例,低恶性胰岛细胞瘤、癌肉瘤各1例;胰腺良性病变10例,均为慢性胰腺炎,其中3例并假性囊肿形成.除8例慢性胰腺炎为临床、放射学随访3～12个月外,余均由组织病理学检查证实.静脉注射18F-FDG 222～296 MBq 1 h后行PET显像.测定肿瘤体积和标准摄取值(SUV),并与PET检查前2周内CT(25例)、MRI(8例)结果对照.结果 20例胰腺恶性肿瘤中19例肿瘤明显摄取18F-FDG,平均SUV 4.91±3.65.10例慢性胰腺炎中9例病灶轻度或无摄取18F-FDG,平均SUV 1.70±1.12(t=2.69,P=0.012).4例肿瘤病灶直径≤3 cm,SUV 2.75±0.63;6例3.1～5 cm,SUV 4.59±3.06;10例>5 cm,SUV 5.46±2.29(χ2=9.02,P=0.011).1例PET假阳性为慢性胰腺炎并假性囊肿,SUV 4.82;1例PET假阴性为胰头癌术后复发,病灶SUV 2.1.以SUV 2.5为胰腺良恶性病变的判断阈值,18F-FDG PET显像诊断胰腺癌灵敏度、特异性和准确性分别为95.0%、90.0%、93.3%,明显高于CT(75.0%、55.6%、68.0%,χ2=5.89,P=0.015).结论 18F-FDG PET显像诊断胰腺癌灵敏度、特异性较高,尤其适于胰腺癌术前分期和术后复发、转移的探查.     

18F-FDG PET-CT对周围型肺癌的诊断价值研究

目的 探讨PET-CT对周围型肺癌的诊断价值.方法 回顾性分析70例经病理证实的周围型肺癌患者的PET-CT影像资料,分析病灶的标准化摄取值(SUV)及其形态学表现.结果 70例周围型肺癌患者中,鳞癌患者32例、腺癌患者25例、小细胞肺癌患者8例、腺鳞癌患者3例、大细胞肺癌2例.平均SUV=4.94±1.53,其中,66例患者的PET影像结果可见18F-FDG高浓聚,SUV≥2.5;另外4例的SUV＜2.5.SUV与肿块大小呈显著相关性.结论 周围型肺癌大多具有较特殊的PET-CT影像学表现.PET-CT对周围型肺癌的诊断及鉴别诊断有较好的效能.SUV结合形态学分析有助于病灶的鉴别诊断.     

18F-FDG PET/CT在黑色素瘤中的应用价值

目的 探讨18F-脱氧葡萄糖(FDG)PET/CT显像在黑色素瘤诊断、临床分期及监测治疗后肿瘤复发与转移灶中的应用价值.方法 黑色素瘤患者61例,均进行18F-FDG PET/CT全身显像.所有PET、CT及PET/CT融合图像均通过融合软件进行帧对帧对比分析.肿瘤病灶根据病理学检查、多种影像学检查及临床随访结果诊断.结果 18F-FDG PET/CT显像对黑色素瘤病灶检出的灵敏度、特异性和准确性分别为90.9%(40/44)、88.2%(15/17)和90.2%(55/61).其中12例治疗前患者中,18F-FDG PET/CT显像诊断的灵敏度为83.3%(10/12).在黑色素瘤病灶局部切除、尚未进行其他治疗的9例患者中,5例残余病灶18F-FDG PET/CT显像检出3例;4例远处转移灶患者全被检出,提高了临床分期,改变了治疗方案.首先发现转移性黑色素瘤病灶并且手术切除后,寻找原发灶的7例患者中,18F-FDG PET/CT检出原发灶2例,4例其他转移灶全被检出.黑色素瘤患者根治术后监测肿瘤复发或转移患者33例,18F-FDG PET/CT显像灵敏度、特异性和准确性分别为100.0%(19/19)、85.7%(12/14)和93.9%(31/33).与同期临床其他影像学检查比较,18F-FDG PET/CT显像发现更多,33例患者中,16例(48.5%)病灶提高临床分期;7例(21.2%)排除可疑病灶,降低临床分期;10例(30.3%)检出病灶与临床一致.结论 18F-FDG PET/CT显像对于黑色素瘤的诊断,残余病灶、复发病灶及转移灶的检出,临床分期的明确具有重要价值.     

Use of a corrected standardized uptake value based on the lesion size on CT permits accurate characterization of lung nodules on FDG-PET

The purpose of this study was to determine the actual standardized uptake value (SUV) by using the lesion size from computer tomography (CT) scan to correct for resolution and partial volume effects in positron emission tomography (PET) imaging. This retrospective study included 47 patients with lung lesions seen on CT scan whose diagnoses were confirmed by biopsy or by follow up CT scan when the PET result was considered negative for malignancy. Each lesion's FDG uptake was quantified by the SUV using two methods: by measuring the maximum voxel SUV (maxSUV) and by using the lesion's size on CT to calculate the actual SUV (corSUV). Among small lesions (2.0 cm or smaller on CT scan), ten were benign and 17 were malignant. The average maxSUV was 1.43+/-0.77 and 3.02+/-1.74 for benign and malignant lesions respectively. When using an SUV of 2.0 as the cutoff to differentiate benignity and malignancy, the sensitivity, specificity, and accuracy were 65%, 70%, and 67% respectively. When an SUV of 2.5 was used for cutoff, the sensitivity, specificity, and accuracy were 47%, 80%, and 59% respectively. The average corSUV was 1.65+/-1.09 and 5.28+/-2.71 for benign and malignant lesions respectively. Whether an SUV of either 2.0 or 2.5 was used for cutoff, the sensitivity, specificity, and accuracy remained 94%, 70%, and 85% respectively. The only malignant lesion that was falsely considered benign with both methods was a bronchioalveolar carcinoma which did not reveal any elevated uptake of fluorine-18 fluorodeoxyglucose (FDG). Of the large lesions (more than 2.0 cm and less than 6.0 cm), one was benign and 19 were malignant and the corSUV technique did not significantly change the accuracy. It is concluded that measuring the SUV by using the CT size to correct for resolution and partial volume effects offers potential value in differentiating malignant from benign lesions in this population. This approach appears to improve the accuracy of FDG-PET for optimal characterization of small lung nodules.     

18F-FDG PET/CT联合肺动脉灌注成像指数在单发肺结节中的应用价值

目的探讨18F-FDG PET/CT联合320容积CT双入口灌注成像(DI-CTP)肺动脉灌注指数(PPI)对单发性肺结节的鉴别诊断价值。方法搜集经病理证实40例单发性肺结节患者的18F-FDG PET/CT及320排CT灌注成像影像资料(恶性结节24例、良性结节16例),PET/CT以结节18F-FDG摄取值SUV≥2.5为诊断恶性结节阈值,18F-FDG PET/CT联合PPI则在SUV≥2.5诊断阈值的基础上综合PPI<50%判定,并分析SUV与PP均值在良恶性结节间差异性及相关性。结果PET/CT联合PPI正确诊断38例,其中恶性结节22例、良性结节16例,误诊2例。18F-FDG PET/CT联合PPI诊断肺单发结节的敏感性91.6%,特异性100%,准确性95.0%;18F-PDG摄取值SUV在良、恶性结间差异无统计学意义(t=1.66,P>0.05),而PPI均值在良、恶性结节间差异有统计学意义(t=-3.14,P<0.01);SUV与PPI间相关性无统计学意义(r=0.20,P>0.05)。结论18F-FDG PET/CT联合PPI可以提高诊断肺单发肺结节敏感性、特异性和准确性,减少误诊率。     

18F-FDG PET/CT显像诊断心包恶性病变的价值

目的 评价18F-脱氧葡萄糖（FDG）PET/CT对心包恶性病变的诊断价值.方法 对23例心包积液患者进行18F-FDG PET/CT显像,并采用两独立样本非参数检验分析良恶性病灶最大标准摄取值（SUVmax）差异有无统计学意义.结果 经病理检查证实恶性心包积液14例,良性心包积液9例.1例PET/CT假阴性,2例PET/CT假阳性.18F-FDG PET/CT鉴别诊断良恶性心包积液的灵敏度、特异性、准确性、阳性预测值、阴性预测值分别为92.9%（13/14）、7/9、87.0%（20/23）、86.7%（13/15）和7/8.良、恶性病变的SUVmax中位值分别为2.2和6.0,两者间比较差异有统计学意义（z=-3.279,P=0.001）.结论 18F-FDG PET/CT是评价心包恶性病变较好的无创性手段,对良恶性心包积液的诊断与鉴别诊断有一定临床价值.     

18F-FDG PET显像在胰腺恶性病变鉴别诊断及转移灶探查中的应用价值

目的研究18F-FDGPET显像在胰腺恶性肿瘤诊断与鉴别诊断中的应用价值。方法 40例临床疑为胰腺恶性病变的患者均行18F-FDGPET显像,对显像结果进行目测法及SUV值半定量分析,并结合CT,MRI等影像学检查进行综合诊断,最后诊断根据手术病理或经4个月以上随访证实。结果如果以SUV为2.5作为鉴别诊断胰腺病灶良恶性的阈值,24例证实为胰腺癌患者中18F-FDGPET显像正确诊断22例,16例胰腺良性病变患者18F-FDGPET检出13例,其灵敏度、特异度及准确性分别为91.7%（22/24）,81.3%（13/16）及87.5%（35/40）;而结合CT,MRI等其他检查结果进行综合诊断,其诊断灵敏度、特异度及准确性分别为91.7%（22/24）、87.5%（14/16）及90%（36/40）。恶性病变的SUV平均值为4.6±2.6,良性病变的SUV平均值为2.3±1.5,良恶性病变间SUV平均值差异有统计学意义（P〈0.01）。在转移灶的检出中,18F-FDGPET显像发现了全部38处转移灶,并发现6处CT,MRI未能发现的远处转移病灶,排除了1例CT认为是胰周转移性淋巴结肿大的病例。结论 18F-FDGPET对鉴别诊断胰腺良恶性肿瘤的灵敏度、特异性较高,尤其在远处转移灶的探查中有较高应用价值。     

基于PET/CT、HRCT特征的评分系统鉴别诊断孤立性肺部病变的临床研究

目的 探讨基于PET/CT、HRCT影像学特征的评分系统对孤立性肺部良恶性病变的诊断价值。方法 回顾性分析行PET/CT检查的孤立性占位性肺病变112例,其中良性病变44例,恶性病变68例。对孤立性肺病变的12项PET/CT及HRCT影像特征进行评估,初步建立量化分级系统,采用受试者工作特征（ROC）曲线分析良恶性病变的最佳诊断评分临界值。结果 PET/CT及HRCT预测孤立性肺部病变的指标包括年龄≥60岁（2分）、病灶大小≥1.0 cm（2分）、密度不均匀（2分）、边界清楚（1分）、SUV_max≥2.5（2分）、ΔSUV_max≥1.0（2分）、滞留指数≥15%（2分）、分叶征（3分）、毛刺征（3分）、胸膜牵拉征（3分）、空泡征（3分）。根据各项指标建立评分系统,随着评分增加,恶性率逐渐增高,通过ROC曲线得出12分为区分良、恶性病变的最佳临界点,灵敏度为92.6%,特异度为81.8%。结论 基于PET/CT、HRCT影像学特征的量化分级系统有助于鉴别孤立性肺部良恶性病变。     

正电子发射计算机体层摄影-CT诊断骨转移瘤的临床价值

目的 应用^18氟-脱氧葡萄糖（^18F-FDG）正电子发射计算机体层摄影（PET）-CT全身显像，探讨PET、同机CT和PET—CT融合图像在骨转移瘤诊断中的价值。方法 共332例^18F-FDG PET—CT受检者中有35例发现骨异常病变。分别阅读和记录^18FDG PET图像、同机CT图像和PET-CT融合图像判断的良、恶性病变，比较3种方法在诊断骨转移瘤上的差异。结果 35例中共检出89个病灶，其中68个病灶最后确诊为恶性肿瘤骨转移，21个为良性病变。PET诊断骨转移病灶62个，诊断良性病变17个，诊断骨转移瘤的敏感性为91．2％（62／68个），特异性为81．0％（17／21个），准确性为88．8％（79／89个）；同机CT诊断骨转移病灶55个，良性病变16个。诊断骨转移瘤的敏感性、特异性和准确性分别为80．9％（55／68个），76．2％（16／21个）和79．8％（71／89个）；PET．CT融合图像诊断骨转移病灶64个，良性病变19个，诊断骨转移瘤的敏感性、特异性和准确性分别为94．1％（64／68个），90．5％（19／21个）和93．2％（83／89个）。结论 PET-CT融合图像在诊断骨转移瘤方面，可减少单用PET或单用CT诊断时的假阴性和假阳性，提高了鉴别骨良、恶性病变的能力。     

18F-FDG PET/CT对不同大小孤立性肺结节的诊断价值

目的 评价18F-脱氧葡萄糖(FDG) PET/CT对不同大小范围孤立性肺结节(SPN)良恶性鉴别诊断的价值.方法 从全国拥有PET/CT的10家医院筛选出已经获得病理学检查结果的SPN病例,收集诊断CT、PET/CT和病理检查结果以及标准摄取值(SUV)、结节大小等资料.诊断CT、PET/CT结果为肺癌、肺癌可能性大、肺癌可能者为阳性;结果为良性病变、良性可能性大、良性可能者为阴性;难以确定阳性和阴性者为不确定.采用SPSS 10.0软件对资料进行分析.结果 120个(120例)SPN中良性结节28个,恶性结节92个.直径或(长径+短径)/2≤1.0cm的结节17个,恶性病变9个;1.1～2.0cm 57个,恶性病变占75.44%;2.1～3.0cm 46个,恶性病变占86.96%.28个良性结节SUV最大值(SUVmax)的平均值为4.5±4.9, SUV平均值(SUVmean)的平均值为2.9±3.6;92个恶性结节SUVmax平均值为6.7±4.2, SUVmean平均值为4.9±3.6;良性结节的SUV显著低于恶性结节的SUV.无论良性还是恶性结节,随着结节的增大,SUV升高.诊断CT对结节良恶性鉴别的灵敏度为78.26%,特异性3/8,准确性72.22%; PET/CT灵敏度为94.51%,特异性64.00%,准确性87.93%.结论 18F-FDG PET/CT在SPN鉴别诊断中具有较高的灵敏度、特异性和准确性,优于诊断CT;结节大小是判断SPN良恶性的重要指标,直径或(长径+短径)/2＞2.0cm的结节,恶性可能性约为87%; SUV可以作为鉴别诊断的依据,但鉴于良性结节SUVmean的平均值为2.9±3.6,界值2.5仅供参考,尤其是对于≤1.0cm的结节.     

Optimal interpretation of FDG PET in the diagnosis, staging and management of pancreatic carcinoma.

This study had two purposes: to optimize the semiquantitative interpretation of 18F-fluorodeoxyglucose (FDG) PET scans in the diagnosis of pancreatic carcinoma by analyzing different cutoff levels for the standardized uptake value (SUV), with and without correction for serum glucose level (SUV(gluc)); and to evaluate the usefulness of FDG PET when used in addition to CT for the staging and management of patients with pancreatic cancer. METHODS: Sixty-five patients who presented with suspected pancreatic carcinoma underwent whole-body FDG PET in addition to CT imaging. The PET images were analyzed visually and semiquantitatively using the SUV and SUV(gluc). The final diagnosis was obtained by pathologic (n = 56) or clinical and radiologic follow-up (n = 9). The performance of CT and PET at different cutoff levels of SUV was determined, and the impact of FDG PET in addition to CT on patient management was reviewed retrospectively. RESULTS: Fifty-two patients had proven pancreatic carcinoma, whereas 13 had benign lesions, including chronic pancreatitis (n = 10), benign biliary stricture (n = 1), pancreatic complex cyst (n = 1) and no pancreatic pathology (n = 1). Areas under receiver operating characteristic curves were not significantly different for SUV and SUV(gluc). Using a cutoff level of 3.0 for the SUV, FDG PET had higher sensitivity and specificity than CT in correctly diagnosing pancreatic carcinoma (92% and 85% versus 65% and 61%). There were 2 false-positive PET (chronic pancreatitis, also false-positive with CT) and 4 false-negative PET (all with true-positive CT, abnormal but nondiagnostic) examinations. There were 5 false-positive CT (4 chronic pancreatitis and 1 pancreatic cyst) and 18 false-negative CT (all with true-positive FDG PET scans) examinations. FDG PET clarified indeterminate hepatic lesions or identified additional distant metastases (or both) in 7 patients compared with CT. Overall, FDG PET altered the management of 28 of 65 patients (43%). CONCLUSION: FDG PET is more accurate than CT in the detection of primary tumors and in the clarification and identification of hepatic and distant metastases. The optimal cutoff value of FDG uptake to differentiate benign from malignant pancreatic lesions was 2.0. Correction for serum glucose did not significantly improve the accuracy of FDG PET. Although FDG PET cannot replace CT in defining local tumor extension, the application of FDG PET in addition to CT alters the management in up to 43% of patients with suspected pancreatic cancer.     

Malignant involvement of the spine: assessment by 18F-FDG PET/CT.

The purpose of the study was to assess the role of (18)F-FDG PET/CT in the assessment of secondary malignant involvement of the spinal column. METHODS: In 51 patients, 242 lesions at the spinal region detected on (18)F-FDG PET/CT were interpreted separately on PET, CT, and fused PET/CT images, including differentiation between benign and malignant lesions and the level in the vertebral column. CT evaluation also included the type of bony lesion (osteolytic, osteoblastic, or mixed) and accompanying soft-tissue abnormalities; for example, epidural masses and tumor involvement of the neural foramina. RESULTS: Of the 242 lesions detected on PET/CT, PET alone identified 220 lesions and CT alone identified 159; 217 (90%) were malignant and 25 benign. (18)F-FDG PET alone detected significantly more malignant lesions than did CT alone (96% vs. 68%, respectively, P < 0.001). The specificity was 56% for both PET alone and CT alone. PET alone was incorrect in determining the level of abnormality within the vertebral column in 33 (15%) lesions and in determining the part of the vertebra involved in 40 (18%) lesions. In 17 (33%) patients, either epidural extension of tumor (n = 7 lesions), neural foramen involvement of tumor (n = 7 lesions), or a combination of both (n = 11 lesions) was detected. On a patient-based analysis, the sensitivity of PET and of PET/CT for the detection of spinal metastasis was 98% and 74%, respectively (P < 0.01). CONCLUSION: (18)F-FDG PET/CT has better specificity for detection of malignant involvement of the spine than does (18)F-FDG PET. It allows for precise localization of lesions and identifies accompanying soft-tissue involvement, which is of potential neurologic significance.