False-Positive Mediastinal Lymphadenopathy on 18F-Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography after Rectal Cancer Resection: A Case Report of Thoracoscopic Surgery in the Prone Position

(18)F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (integrated FDG PET/CT) has been used to diagnose recurrence and differentiate postoperative changes from lymph node metastasis in colorectal cancer, although its accuracy is questionable. We report a prone thoracoscopic surgery for a rectal cancer patient in which false-positive mediastinal lymph nodes were found on FDG-PET/CT. A 60-year-old man underwent a laparoscopic high anterior resection and D3 lymph node dissection for rectal cancer. The histopathological diagnosis was moderately differentiated adenocarcinoma of the rectum, stage IIIB (pT3N1M0), necessitating oral fluoropyrimidine agent S-1. After the primary surgery, a solitary mediastinal lymph node measuring 30 mm in diameter was detected, and abnormal accumulation was confirmed by FDG-PET/CT (SUV(max), 11.7). Thoracoscopic resection was performed in the prone position, but histopathological results showed no metastasis. He was subsequently diagnosed with reactive lymphadenitis. The patient was discharged on postoperative day 4 in good condition and is alive without recurrence 12 months after surgery. PET/CT is useful for the detection of colorectal cancer recurrence; however, it does have a high false-positive rate for mediastinal lymph nodes. There is a limit to its diagnostic accuracy, and one must determine the indication for surgical treatment carefully. Surgery in the prone position is a useful and minimally invasive approach to the mediastinum and allows aggressive resection to be performed.     

The additional value of integrated PET/CT over PET in initial lymph node staging of esophageal cancer

The purpose of the present study was to assess the contribution of simultaneous functional/anatomical imaging using integrated 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT), compared with PET alone for the evaluation of initial lymph node staging in esophageal cancer. We studied 167 consecutive patients with thoracic esophageal squamous cell carcinoma (SCC) who had radical esophagectomy performed between January 1999 and April 2007. For individual nodal group evaluation, PET/CT showed 46.0% sensitivity (p<0.05 vs. PET), 99.4% specificity, 95.1% accuracy (p<0.05 vs. PET), 87.0% positive and 95.5% negative predictive values. PET showed 32.9% sensitivity, 98.9% specificity, 93.1% accuracy, 74.7% positive predictive value and 93.9% negative predictive value. Thus, the sensitivity and accuracy of PET/CT were significantly higher than those of PET. Comparisons between CT, PET and PET/CT in detecting lymph node metastasis by each region showed that PET/CT had a higher sensitivity in lower thoracic regions than PET and CT (p<0.05 vs. CT and PET). Lymph node staging (N0 vs. N1) was not significantly different, but staging per lymph nodal group was significantly better with PET/CT. Integrated PET/CT imaging with co-registration of anatomic and functional imaging data is useful in the initial lymph node staging of patients with operable esophageal cancer compared with PET alone.     

18F—FDGPET／CT在非小细胞肺癌纵隔淋巴结转移上的诊断价值

目的探讨PET／CT在非小细胞肺癌纵隔淋巴结转移上的诊断价值。方法对33例术前行全身18F—FDGPET／CT检查发现肺内病灶,并行根治性手术及系统纵隔淋巴结清扫患者的PET／CT图像进行分析,记录淋巴结短径、CT值、SUVmax等,同时对患者的图像进行视觉分析,应用PET／CT综合分析法对纵隔内淋巴结进行诊断,并与病理结果对照。结果常规CT法对纵隔内淋巴结诊断的准确率为84．1％,常规PET法诊断的准确率为82．8％,常规PET／CT法对纵隔内淋巴结诊断的准确率为91．7％,PET／CT综合分析法的诊断准确率为95．2％,只有5例良性淋巴结误诊为恶性。8例肺癌伴纵隔或肺门淋巴结转移,其中5例肺癌病灶位于肺野内带。结论18F—FDGPET／CT综合分析法对纵隔淋巴结诊断的准确率较高,优于常规CT、常规PET以及常规PET／CT法（）（2=15．1,P〈0．05）;肺癌病灶位于肺野内带者较易发生纵隔或肺门淋巴结的转移。     

18FDG PET/CT对非小细胞肺癌N2期淋巴结诊断的价值

目的:通过对18FDG PET/CT、CT对非小细胞肺癌N2期纵隔淋巴结的诊断与术后病理结果比较,探讨18FDG PET/CT对N2期淋巴结的诊断价值。方法:72例原发NSCLC患者共切除纵隔N2期淋巴结280枚,回顾性分析术前CT及18FDG PET/CT检查对纵隔N2期淋巴结的诊断结果,并与病理结果分别进行对比分析。结果:175枚N2期淋巴结CT诊断阳性,其诊断的敏感度、特异度、准确度、阳性预测值及阴性预测值分别为:74.0%、50%、62.5%、61.7%及63.8%;而172枚N2期淋巴结18FDG PET/CT诊断阳性,其诊断的敏感度、特异度、准确度、阳性预测值及阴性预测值分别为:89.0%、68.7%、79.3%、75.6%及85.2%,均明显优于CT（P＜0.05）。而105例短径<10 mm的纵隔淋巴结中,36.2%（38/105）为转移淋巴结,18FDG PET/CT对CT诊断阴性的纵隔淋巴结的诊断敏感度、特异度、准确度、阳性及阴性预测值分别为:86.8%、88.1%、87.6%、80.5%及92.2%;其中高代谢的N2期小淋巴结主要分布于2R、4R/L、7组:36.4%（12/33）、27.3%（9/33）、36.4%（12/33）。结论:18FDG PET/CT对肺癌N2期纵隔淋巴结的诊断价值明显优于CT,尤其对于纵隔内短径<10 mm淋巴结转移的诊断具有明显优势。     

The incremental effect of positron emission tomography on diagnostic accuracy in the initial staging of esophageal carcinoma

BACKGROUND: The purpose of the current study was to assess whether [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) provides incremental value (e.g., additional information on lymph node involvement or the presence of distant metastases) compared with computed tomography (CT) in patients with esophageal carcinoma. METHODS: The authors examined 149 consecutive patients with thoracic esophageal carcinoma. Eighty-one patients underwent radical esophagectomy without pretreatment, 17 received chemoradiotherapy followed by surgery, 3 underwent endoscopic mucosal resection, and the remaining 48 patients received definitive radiotherapy and chemotherapy. The diagnostic accuracy of FDG-PET and CT was evaluated at the time of diagnosis. RESULTS: The primary tumor was visualized using FDG-PET in 119 (80%) of 149 patients. Regarding lymph node metastases, FDG-PET had 32% sensitivity, 99% specificity, and 93% accuracy for individual lymph node group evaluation and 55% sensitivity, 90% specificity, and 72% accuracy for lymph node staging evaluation. PET exhibited incremental value over CT with regard to lymph node status in 14 of 98 patients who received surgery: 6 patients with negative CT findings were eventually shown to have lymph node metastases (i.e., they had positive PET findings and a positive reference standard [RS]); 6 patients with positive CT findings were shown not to have lymph node metastases (i.e., they had negative PET findings and a negative RS); and 2 patients were shown to have cervical lymph node metastases in addition to mediastinal or abdominal lymph node metastases. Among the remaining patients, PET showed incremental value over CT with regard to distant organ metastases in six patients. The overall incremental value of PET compared with CT with regard to staging accuracy was 14% (20 of 149 patients). CONCLUSIONS: FDG-PET provided incremental value over CT in the initial staging of esophageal carcinoma. At present, combined PET-CT may be the most effective method available for the preoperative staging of esophageal tumors.     

Determination of indication for sentinel lymph node biopsy in clinical node-negative breast cancer using preoperative 18F-fluorodeoxyglucose positron emission tomography/computed tomography fusion imaging

Objective: Sentinel node biopsy (SNB) is indicated for axillary lymph nodemetastasis-negative cases (N0), but clarification of the indicationmay increase treatment efficiency. Fluorine-18-labeled 2-fluoro-2-deoxy-D-glucosepositron emission tomography (FDG-PET) may have a high positivepredictive value in diagnosis of axillary lymph node metastasis. Methods: Ninety-two breasts/axillae were analyzed retrospectively in90 patients (median age 54.6-year old, median primary tumor1.7 cm). FDG-PET/computed tomography was used to indicate SNBin N0 cases. Axillary lymph node dissection (ALND) was performedin cases that were axillary lymph node metastasis-positive (PETN+) on FDG-PET/CT. Results: Seventy-four (80.4%) and 18 (19.6%) of the 92 axillae were diagnosedas metastasis-negative (PET N0) and PET N+, respectively, byFDG-PET/CT. SNB was performed in 51 of the 74 PET N0 axillae.ALND was performed in 23 PET N0 axillae (at the patients’request) and in all 18 PET N+ axillae. Of the 74 PET N0 axillae,14 were metastasis-positive (pN+) and 60 were pN0 pathologically,and of the 18 PET N+ axillae, 13 were pN+ and five were pN0.The sensitivity and specificity of FDG-PET/CT for diagnosisof axillary metastasis were 48.1 and 92.3%, respectively, andthe positive and negative predictive values were 72.2 and 81.1%,respectively. Conclusion: The positive detection rate on FDG-PET/CT was insufficient fordetermining an indication of SNB. However, use of an appropriatecut-off for SUV_max (the positive rate was 90.9% with a cut-offof 2.0) and exclusion of surgically biopsied cases may achievea clinically applicable positive detection rate.     

^18F—FDGPET／CT诊断非小细胞肺癌纵隔淋巴结转移的方法和价值

目的本研究通过目测法、测量法以及模式识别方法对非小细胞肺癌（non—small cell lungcancer,NSCLC）患者纵隔淋巴结的PET／CT图像进行诊断分析,并与病理结果比较,探索各种诊断方法的诊断效能,为临床医生提供有关NSCLC区域淋巴结转移的准确信息。方法选择术前行全身PET／CT检查且经手术根治切除的NSCLC患者28例作为研究对象,由3名有经验的医生分别应用目测法及测量法对淋巴结的CT、PET以及PET／CT图像进行分析,并与病理结果进行对比;同时通过对淋巴结的PET和CT图像的提取,应用工程学一种新的模式识别方法进行分类诊断。结果CT、PET、PET／CT测量法对NSCLC淋巴结诊断的灵敏性分别为53．6％、80．4％、82．1％;特异度分别为92．2％、83．3％、90．6％;阳性预测值分别为68．2％、60．0％、73．0％;阴性预测值分别为86．5％、93．2％、94．2％;诊断符合率分别为83．1％、82．6％、88．6％;CT、PET、PET／CT目测法对NSCLC淋巴结诊断的灵敏性分别为53．6％、71．4％、69．6％;特异度分别为85．0％、82．2％、88．9％;阳性预测值分别为52．6％、55．6％、66．7％;阴性预测值分别为85．5％、90．2％、90．4％;诊断符合率分别为77．5％、79．7％、84．3％。模式识别法计算得出PET的灵敏度为88％,特异度为76％;CT的灵敏度为84％,特异度为66％。结论PET／CT测量法以及目测法对NSCLC淋巴结转移的诊断明显优于单独的CT或单独的PET;PET／CT测量法对NSCLC淋巴结转移的诊断明显优于目测法。初步探索了通过构建多分辨率直方图及支持向量机（SVM）分类判别的工程学方法对淋巴结图像进行分析,为今后多学科联合以及探索更准确的无创检查手段奠定了基础。     

Comparison between positron emission tomography and computed tomography in the use of the assessment of esophageal carcinoma

BACKGROUND: The role and potential value of positron emission tomography (PET) scanning in certain tumors has been widely investigated in recent years. The authors retrospectively assessed the performance of 18-F-fluorodeoxyglucose (FDG)-PET in the assessment of esophageal squamous cell carcinoma (SCC). METHODS: The results using PET were compared with those using computed tomography (CT), and these were correlated with the pathologic findings. The authors studied 32 patients with thoracic esophageal SCC who had undergone radical esophagectomy. RESULTS: Uptake of FDG in the primary tumor was found in 25 of the 32 (78.1%) cases. Comparison of the FDG uptake and the clinicopathologic findings showed that there was a significant association between the FDG uptake and each of the depth of tumor invasion (P < 0.05), occurrence of lymph node metastasis (P < 0.01), and lymphatic invasion (P < 0.01). The survival rate in cases with high FDG uptake (standardized uptake value [SUV], >3) was significantly lower than that in cases with low FDG uptake (SUV, < 3; P < 0.05). In the evaluation of lymph node staging by the detection of lymph node metastasis, FDG-PET showed 77.8% sensitivity, 92.9% specificity, and 84.4% accuracy, and CT scanning showed 61.1% sensitivity, 71.4% specificity, and 65.6% accuracy. Positron emission tomography scanning showed a high degree of accuracy in the neck, upper thoracic, and abdominal regions. However, in the mid- and lower thoracic regions, the sensitivity was very low. The smallest lymph node metastasis that was detected by FDG-PET imaging was 6 mm. The average size of lymph node metastasis that was undetected by FDG-PET scanning was 7.3 mm (range, 1-17 mm). CONCLUSIONS: In conclusion, FDG-PET may be used as a noninvasive diagnostic technique in assessing the aggressiveness of the tumor and the prognosis in patients with esophageal SCC. During the preoperative diagnostic procedures, the sensitivity, specificity, and accuracy of lymph node staging is higher with FDG-PET than with CT imaging. In view of the high specificity of FDG-PET, it also gives useful information to guide the choice of treatment of esophageal carcinoma.     

Maximum standardized uptake value on PET/CT in preoperative assessment of lymph node metastasis from thoracic esophageal squamous cell carcinoma

The presence of lymph node metastasis is an important prognostic factor for patients with esophageal cancer. Accurate assessment of lymph nodes in thoracic esophageal carcinoma is essential for selecting appropriate treatment and forecasting disease progression. Positron emission tomography combined with computed tomography （PET/CT） is becoming an important tool in the workup of esophageal carcinoma. Here, we evaluated the effectiveness of the maximum standardized uptake value （SUVmax） in assessing lymph node metastasis in esophageal squamous cell carcinoma （ESCC） prior to surgery. Fifty-nine surgical patients with pathologically confirmed thoracic ESCC were retrospectively studied. These patients underwent radical esophagectomy with pathologic evaluation of lymph nodes. They all had 18F-FDG PET/CT scans in their preoperative staging procedures. None had a prior history of cancer. The pathologic status and PET/CT SUVmax of lymph nodes were collected to calculate the receiver operating characteristic （ROC） curve and to determine the best cutoff value of the PET/CT SUVmax to distinguish benign from malignant lymph nodes. Lymph node data from 27 others were used for the validation. A total of 323 lymph nodes including 39 metastatic lymph nodes were evaluated in the training cohort, and 117 lymph nodes including 32 metastatic lymph nodes were evaluated in the validation cohort. The cutoff point of the SUVmax for lymph nodes was 4.1, as calculated by ROC curve （sensitivity, 80%; specificity, 92%; accuracy, 90%）. When this cutoff value was applied to the validation cohort, a sensitivity, a specificity, and an accuracy of 81%, 88%, and 86%, respectively, were obtained. These results suggest that the SUVmax of lymph nodes predicts malignancy. Indeed, when an SUVmax of 4.1 was used instead of 2.5, FDG-PET/ CT was more accurate in assessing nodal metastasis.     

非小细胞肺癌术前肺门纵隔淋巴结CT检查和术后病理结果比较的研究

目的 :比较非小细胞肺癌 (NSCLC)患者术前肺门纵隔淋巴结CT检查结果和术中淋巴结情况以及术后病理检查淋巴结转移情况 ,分析探讨CT检查对于诊断肺癌患者肺门纵隔淋巴结转移的价值。方法 :2 0 0 1年 6月 - 2 0 0 3年 5月在我院行手术切除的 86例资料完整的NSCLC患者 ,全部患者均有术前胸部CT、术中肺门纵隔淋巴结描述以及术后病理检查淋巴结转移与否的结果。CT和手术诊断淋巴结异常的标准是 :淋巴结最小径≥ 10mm ,CT检查和术中检查淋巴结异常相一致者定义为敏感性 ,CT发现淋巴结异常而病理报道为淋巴结转移者定义为特异性。结果 :CT检查肺门纵隔淋巴结转移的敏感性和特异性与淋巴结的大小关系密切 ,当淋巴结短径 <10mm时淋巴结的转移率为 16 % (12 77) ;10～19mm时转移率为 4 0 % (5 4 136 ) ;2 0～ 2 9mm时转移率为 75 % (2 7 36 ) ;≥ 30mm时转移率为 6 6。总的敏感性为 6 6 % (16 9 2 5 5 ) ,特异性为 5 1% (131 2 5 5 )。结论 :CT对NSCLC患者肺门纵隔淋巴结转移具有较高的诊断价值 ,尤其淋巴结短径≥ 2 0mm时 ,CT检查的敏感性较高。影响CT准确性的因素有淋巴结大小以及患者是否伴有肿瘤引起的阻塞性肺炎或肺不张     

FDG-PET in staging lung cancer: how does it change the algorithm?

BACKGROUND: In patients with lung cancer, positron emission tomography (PET) using fluor-18-fluorodesoxyglucose (FDG) may be used both to detect extrathoracic metastases (ETM) and for mediastinal lymph node staging (MLS), potentially reducing the need for mediastinoscopy. We assessed the added value of FDG-PET in detecting ETM and focused on the reliability of FDG-PET and mediastinoscopy for MLS. PATIENTS AND METHODS: In 72 consecutive patients with non-small cell lung cancer, the impact of adding FDG-PET to full conventional clinical staging was prospectively analyzed. The predictive value of FDG-PET findings and tumor location for pathologic mediastinal lymph node status were assessed in a logistic regression analysis. RESULTS: Unexpected extrathoracic metastases were detected by FDG-PET in 15% of patients. In MLS overall negative and positive predictive values were 71 and 83% for FDG-PET, and 92 and 100% for mediastinoscopy. However, the negative predictive value of FDG-PET was only 17% in case of FDG-PET positive N1 nodes and/or a centrally located primary tumor, whereas it was 96% in case of FDG-PET negative N1 nodes and a non-centrally located primary tumor. CONCLUSION: By incorporating FDG-PET in clinical staging, 15% of patients with lung cancer are upstaged due to unexpected extrathoracic metastases. In case of a negative mediastinal FDG-PET, mediastinoscopy can only be omitted in the presence of a non-centrally located primary tumor and without FDG-PET positive N1 nodes.     

Combination of FDG PET/CT and Contrast-Enhanced MSCT in Detecting Lymph Node Metastasis of Esophageal Cancer

Background: Lymph node metastasis is believed to be a dependent negative prognostic factor of esophagealcancer. To explore detection methods with high sensitivity and accuracy for metastases to regional and distantlymph nodes in the clinic is of great significance. This study focused on clinical application of FDG PET/CT andcontrast-enhanced multiple-slice helical computed tomography (MSCT) in lymph node staging of esophagealcancer. Materials and Methods: One hundred and fifteen cases were examined with enhanced 64-slice-MSCTscan, and FDG PET/CT imaging was conducted for neck, chest and upper abdomen within one week. Theprimary lesion, location and numbers of metastatic lymph nodes were observed. Surgery was performed withinone week after FDG PET/CT detection. All resected lesions were confirmed histopathologically as the goldstandard. Comparative analysis of the sensitivity, specificity, and accuracy based on FDG PET/CT and MSCTwas conducted. Results: There were 946 lymph node groups resected during surgery from 115 patients, and221 were confirmed to have metastasis pathologically. The sensitivity, specificity, accuracy of FDG PET/CT indetecting lymph node metastasis were 74.7%, 97.2% and 92.0%, while with MSCT they were 64.7%, 96.4%, and89.0%, respectively. A significance difference was observed in sensitivity (p=0.030), but not the others (p>0.05).The accuracy of FDG PET/CT in detecting regional lymph node with or without metastasis were 91.9%, ascompared to 89.4% for MSCT, while FDG PET/CT and MSCT values for detecting distant lymph node with orwithout metastasis were 94.4% and 94.7%. No significant difference was observed for either regional or distantlymph node metastasis. Additionally, for detecting para-esophageal lymph nodes metastasis, the sensitivity ofFDG PET/CT was 72%, compared with 54.7% for MSCT (p=0.029). Conclusions: FDG PET/CT is more sensitivethan MSCT in detecting lymph node metastasis, especially for para-esophageal lymph nodes in esophagealcancer cases, although no significant difference was observed between FDG PET/CT and MSCT in detectingboth regional and distant lymph node metastasis. However, enhanced MSCT was found to be of great value indistinguishing false negative metastatic lymph nodes from FDG PET/CT. The combination of FDG PET/CTwith MSCT should improve the accuracy in lymph node metastasis staging of esophageal cancer.     

Endobronchial ultrasound and value of PET for prediction of pathological results of mediastinal hot spots in lung cancer patients

SUMMARY: In the staging of lung cancer with positron emission tomography (PET) positive mediastinal lymph nodes, tissue sampling is required. The performance of transbronchial needle aspiration (TBNA) using linear endobronchial ultrasound (real-time EBUS-TBNA) under local anaesthesia and the value of PET for prediction of pathological results were assessed in that setting. The number of eluded surgical procedures was evaluated. All consecutive patients with suspected/proven lung cancers and FDG-PET positive mediastinal adenopathy were included. If no diagnosis was reached, further surgical sampling was required. Lymph node SUVmax (maximum standardized uptake value) was assessed in patients whose PET was performed in the leading centre. One hundred and six patients were included. The average number of TBNA samples per patient was 4.9+/-1.1. The prevalence of lymph node metastasis was 58%. Sensitivity, accuracy and negative predictive value of EBUS-TBNA in the staging of mediastinal hot spots were 95, 97 and 91%. Patients without malignant lymph node involvement showed lower SUVmax (respective median values of 3.7 and 10.0; p<0.0001). Surgical procedures were eluded in 56% of the patients. Real-time EBUS-TBNA should be preferred over mediastinoscopy as the first step procedure in the staging of PET mediastinal hot spots in lung cancer patients. In case of negative EBUS, surgical staging procedure should be undertaken. The addition of SUVmax cut-off may allow further refinement but needs validation.     

The role of positron emission tomography in evaluating mediastinal lymph node metastases in non-small-cell lung cancer

Positron emission tomography (PET) is a modality that differentiates malignant from benign processes based upon metabolism rather than anatomy. A number of studies have confirmed improved accuracy of PET over computed tomography (CT), but until a few recent studies, most had failed to include satisfactory histologic confirmation. The objective of this study was to compare PET and CT to histologic staging of the mediastinum in patients with non-small-cell lung cancer (NSCLC). Histologic examination of mediastinal lymph nodes (MLNs) was performed on 40 patients with NSCLC at mediastinoscopy and/or at surgical resection. PET scans were interpreted by one of two nuclear medicine physicians, blinded to histology, using CT scans for anatomic localization. CT scans were independently evaluated for mediastinal lymphadenopathy. The overall accuracy, sensitivity, and specificity of PET were 78% (31 of 40), 67% (four of six), and 79% (27 of 34), respectively. The overall accuracy, sensitivity, and specificity of CT were 68% (27 of 40), 50% (three of six), and 71% (24 of 34), respectively. PET was superior to CT at correctly identifying mediastinal nodal metastases; however, both modalities were inferior to the gold standard of surgical staging. PET is more accurate than CT in staging the mediastinum of patients with NSCLC. PET failed to identify lymph node metastasis in 33% of patients with histologically proven MLN involvement, and false positives were present in 15%. At present, mediastinoscopy should remain the standard of care for preoperative mediastinal staging for NSCLC.     

The role of F-FDG PET/CT for evaluation of metastatic mediastinal lymph nodes in patients with lung squamous-cell carcinoma or adenocarcinoma

Objectives

To evaluate the efficacy of ¹⁸F-FDG PET/CT in depicting metastatic mediastinal lymph nodes in patients with lung squamous-cell carcinoma (LSCC) or lung adenocarcinoma (LAC) in a tuberculosis-endemic country.

Methods

This study retrospectively reviewed patients with LSCC or LAC, who underwent preoperative ¹⁸F-FDG PET/CT to assess mediastinal lymph node metastasis. Patients with the short-axis of mediastinal lymph node ≤ 15 mm were included. PET/CT interpretation was analyzed in two ways. Firstly, with CT for anatomical localization, lymph nodes showing greater ¹⁸F-FDG uptake than vessel pool on PET were regarded malignant. Secondly, lymph nodes with positive uptake on PET were considered malignant, only when nodes had neither calcification nor higher attenuation than vessel pool on CT.

Results

One hundred and sixteen LSCCs and 234 LACs were evaluated. With CT for anatomical localization, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of PET were 78.6%, 45.5%, 53.4%, 31.4% and 87.0% in LSCC group, and 61.8%, 66.3%, 65.0%, 42.9% and 80.9% in LAC group. PET showed higher specificity and accuracy in LAC group compared with LSCC group (p = 0.001 and p = 0.038, respectively). Considering calcification or high attenuation on CT, the sensitivity, specificity, accuracy, PPV and NPV of PET/CT were 71.4%, 67.0%, 68.1%, 40.8% and 88.1% in LSCC group, and 54.4%, 86.1%, 76.9%, 61.7% and 82.2% in LAC group. Compared with PET, PET/CT possessed higher specificity and accuracy in LSCC group (p = 0.000 and p = 0.000, respectively), and higher specificity, accuracy and PPV in LAC group (p = 0.000, p = 0.000 and p = 0.022, respectively).

Conclusions

¹⁸F-FDG PET displays limited efficacy in assessing mediastinal lymph node metastasis with the short-axis diameter <15 mm in LSCC and LAC groups and higher false-positivity in LSCC group. The specificity and accuracy in LSCC and LAC groups are enhanced by interpreting attenuation characteristic on CT.     

Value of PET/CT versus enhanced CT for locoregional lymph nodes in non-small cell lung cancer

PURPOSE: To compare the diagnostic efficacies of integrated (18)F FDG PET/CT images and contrast-enhanced helical CT images in locoregional lymph node metastasis in the patients with non-small cell lung cancer (NSCLC). METHODS: From June 2005 to June 2007, 122 potentially operable patients with proven or suspected non-small cell lung cancer underwent integrated PET/CT and contrast-enhanced CT scans followed by surgical nodal staging. The results of reviewing PET/CT and enhanced CT images for the locoregional lymph node metastasis were compared in relation to pathologic findings. RESULTS: Preoperative nodal staging was compared with postoperative histopathological staging, 80% (98 of 122) of patients correctly staged, 13% (16 of 122) of patients were overstaged, and 7% (8 of 122) were understaged by PET/CT, while those values for CT were 56% (68 of 122), 26% (32 of 122), and 18% (22 of 122), respectively. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of PET/CT for lymph nodes were 86%, 85%, 85%, 64%, 95%, respectively; compared with 69%, 71%, 70%, 43%, 88% for CT (P=0.000, 0.000, 0.000, 0.001, 0.001, respectively). 81% false-negative interpretations and 72% false-positive interpretations on CT were corrected by PET/CT. 57% false-negative interpretations and 45% false-positive interpretations on PET/CT were corrected by CT. 6 % (9 of 153) positive lymph nodes and 8% (40 of 486) negative nodes at pathology were incorrectly diagnosed both by PET/CT and CT. CONCLUSION: Integrated PET/CT improves the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value than enhanced CT in the assessment of locoregional lymph nodes, and provides more efficient and accurate data of nodal staging, with a better effect on diagnosis and therapy in non-small cell lung cancer.     

非小细胞肺癌纵隔淋巴结转移危险因素分析及术前纵隔镜检查的应用策略

目的 探讨纵隔镜技术评估非小细胞肺癌(NSCLC)术前纵隔淋巴结状态(是否存在转移)的临床应用策略.方法 2000年10月至2007年6月,对临床连续收治的经病理确诊的临床分期为Ⅰ～Ⅲ期的NSCLC患者152例,分别采用CT和纵隔镜技术评估纵隔淋巴结状态.根据纵隔淋巴结最终病理结果,计算CT下纵隔肺门淋巴结阴性NSCLC的纵隔镜检查阳性率和实际纵隔淋巴结转移发生率.以患者性别、年龄、肿瘤部位、病理类型、肿瘤T分期、肿瘤类型(中央型或外周型)、CT下纵隔淋巴结大小和血清癌胚抗原(CEA)水平等作为预测因子,进行纵隔淋巴结转移危险因素的单因素和多因素分析.结果 69例CT下纵隔肺门淋巴结阴性NSCLC,纵隔镜检查阳性8例,阳性率为11.6%;实际纵隔淋巴结转移14例,发生率为20.1%.62例临床Ⅰ期(cT1～2NOMO)NSCLC,纵隔镜检查阳性7例,阳性率为11.3%;实际纵隔淋巴结转移12例,发生率为19.4%.对全部152例NSCLC患者纵隔淋巴结转移危险因素的分析结果显示,病理类型和CT下纵隔淋巴结大小是纵隔淋巴结转移的独立危险因素.对69例CT下纵隔肺门淋巴结阴性NSCLC患者纵隔淋巴结转移危险因素的分析结果显示,病理类型是纵隔淋巴结转移的独立危险因素.结论 对于CT下纵隔淋巴结短径≥1 cm的NSCLC患者,术前必须进行纵隔镜检查;对于腺癌患者,即使是CT下纵隔肺门淋巴结短径<1 cm,术前也应该进行纵隔镜检查.     

Detection of extra-axillary lymph node involvement with FDG PET/CT in patients with stage II–III breast cancer

PurposeThe aim of this prospective study was to assess the incidence of extra-axillary lymph node involvement on baseline FDG PET/CT in patients with stage II–III breast cancer scheduled for neo-adjuvant chemotherapy.MethodsPatients with invasive breast cancer of >3 cm and/or proven axillary lymph node metastasis were included for before neo-adjuvant chemotherapy. Baseline ultrasound of the infra- and supraclavicular regions was performed with fine-needle biopsy as needed. Subsequently FDG PET/CT was performed. All visually FDG-positive nodes were regarded as metastatic based on the previously reported high specificity of the technique.ResultsSixty patients were included. In 17 patients (28%) extra-axillary lymph nodes were detected by FDG PET/CT, localised in an intra-mammary node (1 lymph node in 1 patient), mediastinal (2 lymph nodes in 2 patients), internal mammary chain (9 lymph nodes in 8 patients), intra- and interpectoral (6 lymph nodes in 4 patients), infraclavicular (5 lymph nodes in 4 patients) and in the contralateral axilla (3 lymph nodes in 2 patients). Ultrasound-guided cytology had detected extra-axillary lymph node involvement in seven of these patients, but was unable to detect extra-axillary nodes in the other 10 patients with positive extra-axillary lymph nodes on FDG PET/CT. Radiotherapy treatment was altered in 7 patients with extra-axillary involvement (12% of the total group).ConclusionsFDG PET/CT detected extra-axillary lymph node involvement in almost one-third of the patients with stage II–III breast cancer, including regions not evaluable with ultrasound. FDG PET/CT may be useful as an additional imaging tool to assess extra-axillary lymph node metastasis, with an impact on the adjuvant radiotherapy management.     

18fluorodeoxyglucose positron emission tomography to detect mediastinal or internal mammary metastases in breast cancer.

PURPOSE: To determine the prevalence of suspected disease in the mediastinum and internal mammary (IM) node chain by 18fluorodeoxyglucose (FDG) positron emission tomography (PET), compared with conventional staging by computed tomography (CT) in patients with recurrent or metastatic breast cancer. PATIENTS AND METHODS: We retrospectively evaluated intrathoracic lymph nodes using FDG PET and CT data in 73 consecutive patients with recurrent or metastatic breast cancer who had both CT and FDG PET within 30 days of each other. In reviews of CT scans, mediastinal nodes measuring 1 cm or greater in the short axis were considered positive. PET was considered positive when there were one or more mediastinal foci of FDG uptake greater than the mediastinal blood pool. RESULTS: Overall, 40% of patients had abnormal mediastinal or IM FDG uptake consistent with metastases, compared with 23% of patients who had suspiciously enlarged mediastinal or IM nodes by CT. Both FDG PET and CT were positive in 22%. In the subset of 33 patients with assessable follow-up by CT or biopsy, the sensitivity, specificity, and accuracy for nodal disease was 85%, 90%, and 88%, respectively, by FDG PET; 54%, 85%, and 73%, respectively, by prospective interpretation of CT; and 50%, 83%, and 70%, respectively, by blinded observer interpretation of CT. Among patients suspected of having only locoregional disease recurrence (n = 33), 10 had unsuspected mediastinal or IM disease by FDG PET. CONCLUSION: FDG PET may uncover disease in these nodal regions not recognized by conventional staging methods. Future prospective studies using histopathology for confirmation are needed to validate the preliminary findings of this retrospective study.     

核磁共振短时间反转恢复序列技术诊断非小细胞肺癌纵隔淋巴结转移的价值

目的:探索核磁共振短时间反转恢复序列技术（MRI-STIR）诊断非小细胞肺癌纵隔淋巴结转移的价值。方法:回顾性分析了21例病理确诊，并行CT及MRI检查的非小细胞肺癌病例，以探讨MRI-STIR技术诊断非小细胞肺癌纵隔淋巴结转移的精准性。结果:根据单个淋巴结判断MRI-STIR技术的敏感度为52.4%（22/42），特异度为88.8%（103/116），CT检查的敏感度为42.4%（14/33），特异度为86.4%（76/88），MRI-STIR优于CT检查（P<0.05）。结论:MRI-STIR技术可提高诊断非小细胞肺癌纵隔淋巴结转移的精确性。