Accuracy of PET for diagnosis of solid pulmonary lesions with 18F-FDG uptake below the standardized uptake value of 2.5.

Benign and malignant pulmonary lesions usually are differentiated by 18F-FDG PET with a semiquantitative 18F-FDG standardized uptake value (SUV) of 2.5. However, the frequency of malignancies with an SUV of <2.5 is significant, and pulmonary nodules with low 18F-FDG uptake often present diagnostic challenges. METHODS: Among 360 consecutive patients who underwent 18F-FDG PET to evaluate pulmonary nodules found on CT, we retrospectively analyzed 43 who had solid pulmonary lesions (excluding lesions with ground-glass opacity, infiltration, or benign calcification) with an SUV of <2.5. The uptake of 18F-FDG was graded by a visual method (absent, faint, moderate, or intense) and 2 semiquantitative methods (SUV and contrast ratio [CR]). Final classification was based on histopathologic findings or at least 6 mo of clinical follow-up. RESULTS: We found 16 malignant (diameter, 8-32 mm) and 27 benign (7-36 mm) lesions. When faint visual uptake was the cutoff for positive 18F-FDG PET results, the receiver-operating-characteristic (ROC) analysis correctly identified all 16 malignancies and yielded false-positive results for 10 of 27 benign lesions. Sensitivity was 100%, specificity was 63%, and the positive and negative predictive values were 62% and 100%, respectively. When an SUV of 1.59 was the cutoff for positive 18F-FDG PET results, the ROC analysis revealed 81% sensitivity, 85% specificity, and positive and negative predictive values of 77% and 89%, respectively. At a cutoff for positive 18F-FDG PET results of a CR of 0.29, the ROC analysis revealed 75% sensitivity, 82% specificity, and positive and negative predictive values of 71% and 85%, respectively. The areas under the curve in ROC analyses did not differ significantly among the 3 analyses (visual, 0.84; SUV, 0.81; and CR, 0.82). Analyses of intra- and interobserver variabilities indicated that visual and SUV analyses were quite reproducible, whereas CR analysis was poorly reproducible. CONCLUSION: These results suggested that for solid pulmonary lesions with low 18F-FDG uptake, semiquantitative approaches do not improve the accuracy of 18F-FDG PET over that obtained with visual analysis. Pulmonary lesions with visually absent uptake indicate that the probability of malignancies is very low. In contrast, the probability of malignancy in any visually evident lesion is about 60%.     

Standard PET/CT of the chest during shallow breathing is inadequate for comprehensive staging of lung cancer.

The incidence of malignancy associated with subcentimeter pulmonary nodules (micronodules) in patients with malignant disease has been reported to be as high as 58%. Thus, detection of small lung nodules is important for appropriate staging of lung cancer. Because of respiratory motion, small parenchymal lung lesions can be missed on CT acquired during shallow breathing. Micronodules are usually too small to be characterized reliably with 18F-FDG PET. We aimed to determine the incidence of missed pulmonary micronodules on PET/CT studies acquired during shallow breathing. METHODS: The study included 142 consecutive cancer patients (62 male and 80 female; mean age, 54 y) who underwent whole-body PET/CT during shallow breathing and breath-hold CT of the chest during maximal inspiration. CT findings were reviewed independently, and noncalcified nodules missed on the shallow-breathing scan were evaluated for size, location, and metabolic activity. RESULTS: Breath-hold chest CT detected an additional 125 parenchymal lung nodules (mean size, 3.4 +/- 1.6 mm; range, 1-9 mm) in 48 (34%) of the 142 patients. In these patients, 3 nodules, on average, were missed during shallow breathing. In 18 patients (13%), micronodules were identified exclusively on breath-hold images. None of the missed nodules demonstrated 18F-FDG uptake. CONCLUSION: Acquisition of standard PET/CT chest images during shallow breathing is inadequate for comprehensive cancer staging.     

18F-FDG PET/CT显像联合HRCT对孤立性原发肺浸润性黏液腺癌的诊断价值

目的探讨孤立性原发肺浸润性黏液腺癌18F-FDG PET/CT显像和HRCT征象及两者联合对该病的诊断价值。方法回顾性分析经病理证实为浸润性黏液腺癌、有18F-FDG PET/CT双时相显像及病灶层面同机HRCT扫描资料的9例患者,对PET/CT早期、延迟显像及滞留指数、HRCT征象进行综合分析。结果HRCT图像上表现为2例呈实性结节、病灶周围无类似卫星灶样影,6例实性结节周围伴小点片及磨玻璃样影,1例为单纯磨玻璃样结节;分叶征(6例)、血管集束征(6例)、支气管充气征(4例)、空泡征(2例)、毛刺征(1例);18F-FDG PET/CT融合图像上8例病灶表现为不均匀FDG代谢增高,早期显像平均SUVmax为3.2±2.5,延迟现象SUVmax增高6例、降低2例,平均SUVmax为3.5±2.4,平均滞留指数为(10.4±29.3)%,9例均未见纵隔、双侧肺门淋巴结及其他部位转移征象,其18F-FDG PET/CT融合图像上18F-FDG摄取与HRCT相匹配,18F-FDG摄取相对集中于结节的实性区域,病灶磨玻璃区18F-FDG摄取不明显;综合手术病理结果等临床资料证实,9例均为T1N0M0期,与PET/CT分期一致。结论对于影像学检查发现肺孤立性占位患者,在单一影像学检查难以明确诊断的情况下,18F-FDG PET/CT双时相显像上病灶不均匀18F-FDG摄取相对集中于其实性区域的代谢方式与HRCT相联合,可辅助孤立性原发性肺浸润性黏液腺癌的诊断。     

11C-胆碱与18F-FDG双时相PET/CT显像结合高分辨率CT在孤立性肺结节鉴别诊断中的应用

目的比较11C-胆碱（11C-CHO）PET/CT、18F-FDG双时相PET/CT、常规18F-FDG PET/CT、11C-CHO+18F-FDG双时相PET/CT显像结合高分辨率CT（HRCT）4种方法对鉴别诊断孤立性肺结节（SPN）良恶性的价值。方法对28例SPN患者进行18F-FDG PET/CT显像（注药后l h显像,2 h行延迟显像）和11C-CHO PET/CT显像（于注药10 min后进行）。PET图像判断以SPN最大截面勾画ROI,计算SUV_max作为半定量指标,SUV_max ≥ 2.5为阳性,18F-FDG PET/CT延迟显像SUV_max上升10%为恶性病变（阳性）,下降或升高 < 10%为良性病变（阴性）。HRCT以是否有分叶征、短细毛刺、胸膜尾征、支气管充气征、血管集束征、空泡征为分析良恶性的指征。所有病例进行临床综合分析及随访,以影像诊断是否符合临床随访及病理结果作为判断标准。组间SUV_max的比较采用t检验;计数资料的比较采用χ2检验。结果 28例SPN患者中,病理或临床随访诊断发现肺癌17例,结核7例,结节病4例。常规18F-FDG PET/CT显像确诊21例,18F-FDG双时相PET/CT显像确诊24例,11C-CHO PET/CT显像确诊23例,11C-CHO +18F-FDG双时相PET/CT+HRCT确诊27例。28例患者良恶性结节的18F-FDG及11C-CHO PET/CT的SUV_max比较,差异有统计学意义（t=10.57和13.19,均P < 0.05）。良恶性结节分叶、毛刺、胸膜尾征、血管集束征之间的差异有统计学意义（χ2=9.27、10.36、14.31和17.52,均P < 0.05）。11C-CHO+18F-FDG双时相PET/CT+HRCT联合显像的灵敏度为81.8%,特异度为94.1%,准确率为96.4%,明显高于非联合显像。结论 11C-CHO+18F-FDG双时相PET/CT+HRCT能较好地鉴别SPN的良恶性,三者联合能提高对SPN的诊断率。     

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.     

Elevated uptake of 18F-FDG in PET/CT imaging of a nocardial pleural nodule

18-Fluoredeoxyglucose position emission tomography and computed tomography ((18)F-FDG PET/CT) scanning has been widely used in the assessment of malignancy. We report here an increased (18)F-FDG uptake in pleural nodules in the PET/CT scan images of a patient having recurrent fever and chest pain. Further studies with bacterial culture and histopathology of biopsy confirmed the lesions as nocardial infection. To our knowledge, it is the first report of PET /CT findings in pleural multiple irregular nodules with nocardial infection. Our study suggests that a combination of FDG-PET/CT scanning and pathological study may be considered in distinguishing uncommon benign lesions in the lung.     

18F-FLT和18F-FDG PET/CT SUVmax鉴别诊断肺结节的价值

目的 探讨18F-脱氧胸腺嘧啶核苷(FLT)和18F-脱氧葡萄糖(FDG)最大标准摄取值(SUVmax)在肺结节良恶性定性诊断上的价值.方法 自2006年1月至2007年6月,6个PET/CT中心对肺结节样病变开展了18F-FLT和18F-FDG PET/CT显像的多中心临床研究.共有55例患者被纳入该研究[男33例,女22例,年龄(53.3±17.1)岁],所有病例均行2种显像剂显像,并通过病理检查或随访确诊.对2种PET/CT显像结果分别进行视觉分析和半定量分析.采用SPSS13.0软件进行统计学处理.结果 (1)良性病变39例,恶性病变16例.(2)以病理检查或随访结果作为肺癌确诊的"金标准",与"金标准"进行比较,单独以18F-FDG的SUVmax＞2.5和18F-FLT的SUVmax＞1.35为阈值,对肺癌诊断的灵敏度、特异性、准确性分别为93.8%(15/16)、25.6%(10/39)、45.5%(25/55)和93.8%(15/16)、41.O%(16/39)、56.4%(31/55);18F-FDG及18F-FLT双盲和集体阅片诊断肺癌的灵敏度、特异性、准确性分别为87.5%(14/16)、59.0%(23/39)、67.3%(37/55)和68.8%(11/16)、76.9%(30/39)、74.5%(41/55);18F-FDG+18F-FLT双盲和集体阅片诊断肺癌的灵敏度、特异性、准确性分别为81.3%(13/16)、87.2%(34/39)、85.5%(47/55).(3)18F-FDG诊断肺癌的受试者工作特征(ROC)曲线下面积为0.744;18F-FLT诊断肺癌的ROC曲线下面积为0.783.(4)55例病例的18F-FLT、18F-FDG的SUVmax Pearson相关系数(r)=0.614,P＜0.05,表明二者呈线性相关.结论 18F-FDG诊断肺癌的灵敏度较18F-FLT高,但特异性低;18F-FLT的诊断能力较18F-FDG好;二者具有一定的相关性;二者联合诊断可以明显提高诊断准确性.     

18F-FDG PET/CT结合高分辨率CT对孤立性肺结节的

 目的 探讨18F-FDG PET/CT显像结合高分辨率CT(high resolution CT,HRCT)对孤立性肺结节(solitary pulmonary nodule,SPN)的诊断价值。方法 回顾性分析124例SPN患者的18F-FDG PET/CT检查资料,其中76例加做HRCT扫描,所有病例经病理或临床随访证实。18F-FDG PET/CT通过目测法和半定量法判断病灶的代谢情况,结合CT或HRCT病灶的形态学特征判断良、恶性。结果 48例仅行18F-FDG PET/CT检查的SPN患者,正确诊断32例为恶性,8例为良性,假阳性与假阴性各4例。76例加做HRCT的患者,正确诊断62例恶性与8例良性,假阳性与假阴性分别为2例和4例。18F-FDG PET/CT 结合HRCT与单纯18F-FDG PET/CT诊断SPN的灵敏度、特异性及准确率分别为94%、80%、90%与89%、67%、83%。结论 18F-FDG PET/CT协同HRCT可提高对SPN性质判断的灵敏度、特异性及准确率。     

Tissue characterization of solitary pulmonary nodule: comparative study between helical dynamic CT and integrated PET/CT.

Recent advances in the technology of helical multidetector CT allow precise evaluations of nodule hemodynamics. In addition, the efficacy of tissue characterization has improved, and now sensitivity and specificity of >90% are achieved. Moreover, the efficacy of PET for the tissue characterization of solitary pulmonary nodules (SPNs) has also become of importance. The purpose of this study was to compare the diagnostic accuracy of helical dynamic (HD) CT (HDCT) and integrated PET/CT for pulmonary nodule characterization. METHODS: One hundred nineteen patients with an SPN underwent both HDCT (unenhanced scans, followed by series of images at 30, 60, 90, 120 s and at 5 and 15 min after intravenous injection of contrast medium) and integrated PET/CT. On HDCT, a nodule was regarded as malignant with a net enhancement of > or =25 Hounsfield units (HU) and a washout of 5-31 HU. On integrated PET/CT, nodules were considered malignant with a > or =3.5 maximum standardized uptake value and an 18F-FDG uptake greater than that of mediastinal structures. The sensitivity, specificity, and accuracy of the 2 modalities for malignancy were compared using the McNemar test. RESULTS: There were 79 malignant and 40 benign nodules. The sensitivity, specificity, and accuracy for malignancy on HDCT were 81% (64/79 nodules), 93% (37/40), and 85% (101/119), respectively, whereas those on integrated PET/CT were 96% (76/79), 88% (35/40), and 93% (111/119), respectively (P = 0.008, 0.727, and 0.011, respectively). All malignant nodules were interpreted correctly on either HDCT or PET/CT. CONCLUSION: Integrated PET/CT is more sensitive and accurate than HDCT for the malignant nodule characterization; therefore, PET/CT may be performed as the first-line evaluation tool for SPN characterization. Because HDCT has high specificity and acceptable sensitivity and accuracy, it may be a reasonable alternative for nodule characterization when PET/CT is unavailable.     

A multicenter clinical trial on the diagnostic value of dual-tracer PET/CT in pulmonary lesions using 3'-deoxy-3'-18F-fluorothymidine and 18F-FDG.

Some new radiotracers might add useful information and improve diagnostic confidence of (18)F-FDG imaging in tumors. A multicenter clinical trial was designed to investigate the diagnostic performance of dual-tracer ((18)F-FDG and 3'-deoxy-3'-(18)F-fluorothymidine [(18)F-FLT]) PET/CT in pulmonary nodules. METHODS: Fifty-five patients underwent dual-tracer imaging in 6 imaging centers using the same models of equipment and standardized protocols. The images were interpreted by a collective group of readers who were unaware of the clinical data. The diagnostic performance using either tracer alone or dual-tracers together, with or without CT, was compared. The histological diagnosis or clinical findings in a 12-mo follow-up period served as the standard of truth. RESULTS: In 16 patients with malignant tumor, 16 with tuberculosis, and 23 with other benign lesions, the sensitivity and specificity of (18)F-FDG and (18)F-FLT were 87.5% and 58.97% and 68.75% and 76.92%, respectively. The combination of dual-tracer PET/CT improved the sensitivity and specificity up to 100% and 89.74%. The 3 subgroups of patients could be best separated when the (18)F-FLT/(18)F-FDG standardized uptake value ratio of 0.4-0.90 was used as the threshold. CONCLUSION: By reflecting different biologic features, the dual-tracer PET/CT using (18)F-FDG and (18)F-FLT favorably affected the diagnosis of 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。     

Imaging proliferation in lung tumors with PET: 18F-FLT versus 18F-FDG.

Recently, the thymidine analog 3'-deoxy-3'-(18)F-fluorothymidine (FLT) was suggested for imaging tumoral proliferation. In this prospective study, we examined whether (18)F-FLT better determines proliferative activity in newly diagnosed lung nodules than does (18)F-FDG. METHODS: Twenty-six patients with pulmonary nodules on chest CT were examined with PET and the tracers (18)F-FDG and (18)F-FLT. Tumoral uptake was determined by calculation of standardized uptake value (SUV). Within 2 wk, patients underwent resective surgery or had core biopsy. Proliferative activity was estimated by counting nuclei stained with the Ki-67-specific monoclonal antibody MIB-1 per total number of nuclei in representative tissue specimens. The correlation between the percentage of proliferating cells and the SUVs for (18)F-FLT and (18)F-FDG was determined using linear regression analysis. RESULTS: Eighteen patients had malignant tumors (13 with non-small cell lung cancer [NSCLC], 1 with small cell lung cancer, and 4 with pulmonary metastases from extrapulmonary tumors); 8 had benign lesions. In all visible lesions, mean (18)F-FDG uptake was 4.1 (median, 4.4; SD, 3.0; range, 1.0-10.6), and mean (18)F-FLT uptake was 1.8 (median, 1.2; SD, 2.0; range, 0.8-6.4). Statistical analysis revealed a significantly higher uptake of (18)F-FDG than of (18)F-FLT (Mann-Whitney U test, P < 0.05). (18)F-FLT SUV correlated better with proliferation index (P < 0.0001; r = 0.92) than did (18)F-FDG SUV (P < 0.001; r = 0.59). With the exception of 1 carcinoma in situ, all malignant tumors showed increased (18)F-FDG PET uptake. (18)F-FLT PET was false-negative in the carcinoma in situ, in another NSCLC with a low proliferation index, and in a patient with lung metastases from colorectal cancer. Increased (18)F-FLT uptake was related exclusively to malignant tumors. By contrast, (18)F-FDG PET was false-positive in 4 of 8 patients with benign lesions. CONCLUSION: (18)F-FLT uptake correlates better with proliferation of lung tumors than does uptake of (18)F-FDG and might be more useful as a selective biomarker for tumor proliferation.     

60例3厘米以下肺内球形病灶瘤─肺界面CT─病理对照分析

本文复习了经手术病理证实的直径≤３ｃｍ的肺内孤立性球形病灶６０例（肺癌４２例、良性结节１８例）的ＣＴ像。ＣＴ像显示结节边缘粗糙者小肺癌占８１％，良性结节占２８％。结节主要ＣＴ像层面上多毛刺（多于６根）结节小肺癌占７１％，良性结节仅占１１％。ＣＴ像见结节边缘有锯齿征９例，病理证实均为肺癌，此征与癌灶边缘不等速浸润生长有关。ＣＴ－病理对照结果显示锯齿征是诊断周围型小肺癌很重要的一个ＣＴ征象，ＣＴ像上结节边缘光滑程度及毛刺数的多少有助于肺周围球形小病灶的良、恶性鉴别诊断。     

Comparison of lesion-to-cerebellum uptake ratios and standardized uptake values in the evaluation of lung nodules with 18F-FDG PET

OBJECTIVE: To evaluate the clinical performance of the lesion-to-cerebellum uptake ratio (LCR), a semiquantitative index for differentiating malignant from benign lung nodules with [F]fluorodeoxyglucose positron emission tomography (F-FDG PET). METHODS: Thirty-six patients (16 females, 20 males; median age, 73 years; range, 41-87 years) with 42 known or suspected malignant lung nodules underwent whole-body PET imaging after an intravenous injection of a mean dose of 543+/-69 MBq (14.7+/-1.9 mCi) of F-FDG. The standardized uptake value (SUV) and the LCR were calculated for each nodule and receiver operating characteristic (ROC) curves were analysed using the ROCKIT 0.9B software package. RESULTS: Surgical pathology and follow-up with serial computed tomography scans for at least 24 months revealed 18 malignant lung lesions and 24 benign lesions less than 3.0 cm in size. The mean LCR was 0.70+/-0.40 for malignant nodules and 0.23+/-0.12 for benign nodules (P<0.001, two-tailed test). The area under the estimated ROC curve was 0.8660 for SUV data and 0.9197 for LCR data (P=0.2408, two-tailed test). CONCLUSIONS: The LCR method appears to be a valuable semiquantitative index for the evaluation of malignancy in pulmonary nodules with F-FDG PET, which is simple to perform clinically and does not require accurate measurements of body weight or the residual activity in the syringe utilized for F-FDG injection.     

Utility of 18F-FDG PET in evaluating cancers of lung

PET has seen rapid progression in recent years, with applications in oncology leading the way. The glucose analog (18)F-FDG is the most commonly used PET radiopharmaceutical and has been shown to accumulate avidly in several different neoplasms, including cancers of the lung. The following discussion will review the physiologic basis for the uptake of (18)F-FDG in lung neoplasms and demonstrate the utility of (18)F-FDG PET in lung cancer. A brief review of other PET radiopharmaceuticals in lung cancer imaging, and dual-modality PET/CT scanners, will be presented. Upon completion of this article, the reader should be able to describe the pharmacokinetics of (18)F-FDG and discuss the efficacy of (18)F-FDG PET scans in the evaluation of solitary pulmonary nodules, disease staging, and monitoring response to therapy. Additionally, the reader should be able to compare (18)F-FDG PET with conventional anatomic imaging and describe some of the technical challenges of PET/CT fusion imaging.     

^（18）F-FDG符合线路显像对孤立性肺结节的诊断价值

目的探讨^18F-氟脱氧葡萄糖双探头符合线路显像对肺部孤立性结节的诊断价值。方法回顾性分析34例孤立性结节的^18F-氟脱氧葡萄糖双探头符合线路显像及胸部多层螺旋CT检查结果,并结合病理分析。结果双探头符合线路显像诊断恶性病灶28个,良性病变6个。CT诊断恶性病灶29个,良性病灶5个。病理结果提示恶性病灶26个,良性病变8个。双探头符合线路显像诊断孤立性肺结节的灵敏度96%,特异性67%,准确性88%,阳性预测率81%,阴性预测率83%。多层螺旋CT诊断孤立性肺结节的灵敏度92%,特异性38%,准确性79%,阳性预测率83%,阴性预测率60%。结论^18F-氟脱氧葡萄糖探头符合线路显像对诊断孤立性肺结节有临床价值,其特异性、准确性和阴性预测率均高于CT。     

Focal thyroid lesions incidentally identified by integrated 18F-FDG PET/CT: clinical significance and improved characterization.

In this retrospective study, we investigated whether the (18)F-FDG uptake pattern and CT findings improved the accuracy over the standardized uptake value (SUV) for differentiating benign from malignant focal thyroid lesions incidentally found on (18)F-FDG PET/CT. We also defined the prevalence of these lesions and their risk for cancer. METHODS: (18)F-FDG PET/CT was performed on 1,763 subjects without a previous history of thyroid cancer from May 2003 to June 2004. Two nuclear medicine physicians and 1 radiologist interpreted PET/CT images, concentrating on the presence of focal thyroid lesions, the maximum SUV of the thyroid lesion, the pattern of background thyroid (18)F-FDG uptake, and the CT attenuation pattern of the thyroid lesion. RESULTS: The prevalence of focal thyroid lesions on PET/CT was 4.0% (70/1,763). Diagnostic confirmation was done on 44 subjects by ultrasonography (US)-guided fine-needle aspiration (n = 29) or US with clinical follow-up (n = 15). Among 49 focal thyroid lesions in these 44 subjects, 18 focal thyroid lesions of 17 subjects were histologically proven to be malignant (papillary cancer in 16, metastasis from esophageal cancer in 1, non-Hodgkin's lymphoma in 1). Therefore, the cancer risk of focal thyroid lesions was 36.7% on a lesion-by-lesion basis or 38.6% on a subject-by-subject basis. The maximum SUV of malignant thyroid lesions was significantly higher than that of benign lesions (6.7 +/- 5.5 vs. 10.7 +/- 7.8; P < 0.05). When only the maximum SUV was applied to differentiate benign from malignant focal thyroid lesions for the receiver-operating-characteristic curve analysis, the area under the curve (AUC) of PET was 0.701. All 16 focal thyroid lesions with very low attenuation or nonlocalization on CT images, or with accompanying diffusely increased thyroid (18)F-FDG uptake, were benign. When those lesions were regarded as benign lesions, irrespective of the maximum SUV, the AUC of PET/CT was significantly improved to 0.878 (P < 0.01). CONCLUSION: Focal thyroid lesions incidentally found on (18)F-FDG PET/CT have a high risk of thyroid malignancy. Image interpretation that includes (18)F-FDG uptake and the CT attenuation pattern, along with the SUV, significantly improves the accuracy of PET/CT for differentiating benign from malignant focal thyroid lesions.     

11C-胆碱与18F-FDG双时相PET显像在孤立性肺结节鉴别诊断中的应用

目的 比较^11C-胆碱、18F-脱氧葡萄糖（FDG）和^18F-FDG双时相PET显像对鉴别肺部孤立性结节良恶性的价值。方法16例临床疑为肺肿瘤的患者进行^18F-FDGPET显像（注药后1h显像，2h后行延迟显像）、^11C-胆碱PET显像（3d内，于注药后10min进行）。图像判断以标准摄取值（SUV）作为半定量指标，异常放射性浓聚灶以SUV〉2．5为葡萄糖代谢增高，^18F-FDG延迟显像SUV上升≥10％为恶性病变（阳性），如下降或升高〈10％为良性病变（阴性）；^11C-胆碱异常摄取灶以SUV〉2．0为阳性。所有病例进行随访，以显像诊断是否符合病理检查结果作为判断标准。结果病理检查结果证实12例肺癌，3例结核，1例结节病。^11C-胆碱PET显像确诊了12例肿瘤中的ll例，而^18F-FDG PET显像确诊10例（10／12例），双时相^18F-FDG PET显像确诊11例。4例良性病变者，^11C-胆碱PET显像能较好鉴别；而^18F-FDG PET显像2例假阳性，结合延迟显像仅1例假阳性。结论 ^11C-胆碱和^18F-FDG PET显像均能较好地鉴别肺部良恶性肿瘤。但^11C-胆碱和双时相^18F-FDGPET显像优于常规^18F-FDGPET显像，三者联合能提高对肺部病变的诊断效率。     

~(18)F-FDG PET-CT和双源CT的LungCare软件在评估孤立性肺结节中的比较研究

目的 探讨18-氟-脱氧葡萄糖(~(18)F-FDG)PET/CT显像及Siemens双源CT的LungCare软件对孤立性肺结节(SPN)的辅助诊断能力及适用范围.方法 回顾分析经病理证实的24例SPN患者的PET-CT图像资料,并与利用双源CT的LungCare软件分析SPN进行比较研究.用χ~2检验对2种检查方法的评价结果进行统计学分析,以P<0.05作为差异有显著意义.结果 在24例SPN中,恶性结节15例,良性结节9例.LungCare软件评估其良恶性的准确性、敏感性、特异性、阳性预测值、阴性预测值分别为83.3%、80.0%、88.8%、92.3%、72.7%,PET-CT评估其良恶性的准确性、敏感性、特异性、阳性预测值、阴性预测值分别为87.5%、93.3%、77.7%,87.5%、87.5%.LungCare软件和PET/CT定性SPN的准确性相当,两者之间并不存在明显的差异(P>0.05).PET/CT的敏感性、阴性预测值明显高于LungCare软件,但其特异性、阳性预测值明显低于LungCare软件(P<0.05).结论 ~(18)F-FDG PET-CT对肺结节的诊断有一定辅助作用,适用于对孤立性肺结节的良恶性鉴别诊断.PET/CT密切结合LungCare软件,可进一步提高诊断正确率.     

孤立性肺结核球的~(18)F-FDGPET/CT影像学表现

目的：探讨孤立性肺结核球（PTM）的18F-脱氧葡萄糖（FDG）PET/CT影像学表现。方法：回顾性分析23例经病理或临床证实为孤立性PTM患者的18F-FDG PET/CT影像学资料,所有患者均经注射18F-FDG 60min后行螺旋CT平扫和PET显像,分别对PTM进行形态学分析和标准摄取值（SUV）半定量分析。结果：23例病例中,CT平扫显示孤立性PTM直径为1.11~5.10 cm,平均2.48 cm;结节边缘光滑者16例,结节内有空洞者4例、钙化者3例;同时合并纵隔、肺门或腋窝淋巴结增大者6例。本组患者中17例发生18F-FDG摄取,其中11例表现为肺内结节局限性18F-FDG浓聚,6例表现为肺内结节和增大淋巴结18F-FDG浓聚,平均SUVmax为4.01±1.89;12例18F-FDG摄取阳性的患者经抗结核治疗后病灶缩小;6例未发生18F-FDG摄取的患者,经CT随访12个月病灶无明显变化。结论：18F-FDG PET/CT对孤立性PTM的诊断具有重要价值,确诊有赖于穿刺活检或手术病理。