^18F-FDG PET／CT在胰腺癌诊断中的价值

目的评价^18F-脱氧葡萄糖（FDG）PET／CT鉴别诊断胰腺良恶性病变及检测淋巴结和（或）远处转移的价值。方法回顾性分析上海交通大学医学院附属仁济医院行^18F—FDGPET／CT检查的46例临床疑胰腺肿瘤患者的影像学检查资料和临床资料,其中胰腺癌患者26例,良性病变者20例,比较分析PET和CT的特征。结果当选择最大标准摄取值（SUVmax）=2．95为判断良恶性的界值时,对胰腺癌诊断的灵敏度是88．5％（23／26）,特异性是85．0％（17／20）。^18F—FDGPET／CT显像假阳性3例,假阴性3例。同时发现16例检查前未确定的肝、肺、骨及淋巴结转移患者。根据显像结果,11例患者治疗方案得以修正。结论根据现有资料分析,^18F—FDGPET／CT是鉴别诊断胰腺良恶性病变及检测胰腺癌患者淋巴结和（或）远处转移一种较好的方法。     

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。     

18F-FDG PET/CT for staging of penile cancer.

The value of PET or PET/CT with (18)F-FDG for the staging of penile cancer has yet to be determined. The objective of this study was to investigate the pattern of (18)F-FDG uptake in the primary malignancy and its metastases and to determine the diagnostic value of (18)F-FDG PET/CT in the staging and restaging of penile cancer. METHODS: Thirteen patients (mean +/- SD age, 64 +/- 14.0 y) with suspected penile cancer or suspected recurrent disease were examined with a Gemini PET/CT system (200 MBq of (18)F-FDG). The reference standard was based on histopathologic findings obtained at biopsy or during surgery. RESULTS: Both the primary tumor and regional lymph node metastases exhibited a pattern of (18)F-FDG uptake typical for malignancy. Sensitivity in the detection of primary lesions was 75% (6/8), and specificity was 75% (3/4). On a per-patient basis, sensitivity in the detection of lymph node metastases was 80% (4/5), and specificity was 100% (8/8). On a nodal-group basis, PET/CT showed a sensitivity of 89% (8/9) in the detection of metastases in the superficial inguinal lymph node basins and a sensitivity of 100% (7/7) in the deep inguinal and obturator lymph node basins. The mean +/- SD maximum standardized uptake value for the 8 primary lesions was 5.3 +/- 3.7, and that for the 16 lymph node metastases was 4.6 +/- 2.0. CONCLUSION: According to our results, the main indication for (18)F-FDG PET in the primary staging or follow-up of penile cancer patients may be the prognostically crucial search for lymph node metastases. With the use of a PET/CT unit, the additional information provided by CT may be especially useful for planning surgery. Implementing (18)F-FDG PET and PET/CT in future staging algorithms may lead to a more precise and stage-appropriate therapeutic strategy. Furthermore, invasive procedures with a high morbidity rate, such as general bilateral lymphadenectomy, may be avoided.     

Fluorine-18 2-deoxy-2-fluoro-D-glucose PET in the preoperative staging of breast cancer: comparison with the standard staging procedures

The present study compared the diagnostic accuracy of fluorine-18 2-deoxy-2-fluoro-D-glucose positron emission tomography (FDG-PET) with conventional staging techniques. The differentiation between malignant and benign lesions and the detection of multifocal disease, axillary and internal lymph node involvement, and distant metastases were evaluated. One hundred and seventeen female patients were prospectively examined using FDG-PET and conventional staging methods such as chest X-ray, ultrasonography of the breast and liver, mammography and bone scintigraphy. All patients were examined on a modern full-ring PET scanner. Histopathological analysis of resected specimens was employed as the reference method. The readers of FDG-PET were blinded to the results of the other imaging methods and to the site of the breast tumour. The sensitivity and specificity of FDG-PET in detecting malignant breast lesions were 93% and 75% respectively. FDG-PET was twofold more sensitive (sensitivity 63%, specificity 95%) in detecting multifocal lesions than the combination of mammography and ultrasonography (sensitivity 32%, specificity 93%). Sensitivity and specificity of FDG-PET in detecting axillary lymph node metastases were 79% and 92% (41% and 96% for clinical evaluation). FDG-PET correctly indicated distant metastases in seven patients. False-positive or false-negative findings were not encountered with FDG-PET. Chest X-ray was false-negative in three of five patients with lung metastases. Bone scintigraphy was false-positive in four patients. Three patients were upstaged since FDG-PET detected distant metastases missed with the standard staging procedure. It is concluded that, compared with the imaging methods currently employed for initial staging, FDG-PET is as accurate in interpreting the primary tumour and more accurate in screening for lymph node metastases and distant metastases. Due to a false-negative rate of 20% in detecting axillary lymph node metastases, FDG-PET cannot replace histological evaluation of axillary status.     

Fluorine-18 2-deoxy-2-fluoro-D-glucose PET in the preoperative staging of breast cancer: comparison with the standard staging procedures

The present study compared the diagnostic accuracy of fluorine-18 2-deoxy-2-fluoro-D-glucose positron emission tomography (FDG-PET) with conventional staging techniques. The differentiation between malignant and benign lesions and the detection of multifocal disease, axillary and internal lymph node involvement, and distant metastases were evaluated. One hundred and seventeen female patients were prospectively examined using FDG-PET and conventional staging methods such as chest X-ray, ultrasonography of the breast and liver, mammography and bone scintigraphy. All patients were examined on a modern full-ring PET scanner. Histopathological analysis of resected specimens was employed as the reference method. The readers of FDG-PET were blinded to the results of the other imaging methods and to the site of the breast tumour. The sensitivity and specificity of FDG-PET in detecting malignant breast lesions were 93% and 75% respectively. FDG-PET was twofold more sensitive (sensitivity 63%, specificity 95%) in detecting multifocal lesions than the combination of mammography and ultrasonography (sensitivity 32%, specificity 93%). Sensitivity and specificity of FDG-PET in detecting axillary lymph node metastases were 79% and 92% (41% and 96% for clinical evaluation). FDG-PET correctly indicated distant metastases in seven patients. False-positive or false-negative findings were not encountered with FDG-PET. Chest X-ray was false-negative in three of five patients with lung metastases. Bone scintigraphy was false-positive in four patients. Three patients were upstaged since FDG-PET detected distant metastases missed with the standard staging procedure. It is concluded that, compared with the imaging methods currently employed for initial staging, FDG-PET is as accurate in interpreting the primary tumour and more accurate in screening for lymph node metastases and distant metastases. Due to a false-negative rate of 20% in detecting axillary lymph node metastases, FDG-PET cannot replace histological evaluation of axillary status.     

PET/CT与增强CT检测乳腺癌及其腋淋巴结转移的对照研究

目的探讨^18F-脱氧葡萄糖（FDG）PET／CT显像与螺旋CT增强扫描检测乳腺癌及其腋淋巴结转移的临床价值。方法27例乳腺肿块患者于同日行^18F—FDG PET／CT显像与CT增强扫描。患者俯卧于乳腺专用泡沫垫上接受检查，前者图像由3位核医学科医师采用目测法结合半定量法进行诊断，后者图像由3位影像科医师分析诊断；最后与病理检查结果对照。结果27例患者PET／CT与增强CT均发现31个乳腺肿块，病理检查证实其中21个为乳腺癌，10个为良性病变；发现腋淋巴结91个，共有66个转移（1例有双侧腋淋巴结转移）；PET／CT显像检测乳腺癌原发灶的灵敏度为80．95％，特异性为90％，阳性预测值为94．44％；检测淋巴结转移的灵敏度为89．39％，特异性为88％，阳性预测值为95．16％。增强CT检测乳腺癌原发灶的灵敏度为90．48％，特异性为60％，阳性预测值为82．61％；检测淋巴结转移的灵敏度为86．36％，特异性为52％，阳性预测值为82．61％。^18F—FDG PET／CT和增强CT对腋淋巴结状态的诊断与病理检查结果的列联系数分别为0．64和0．37；两者对乳腺癌及其腋淋巴结转移的诊断特异性差异有显著性（P〈0．05）；对直径〈2cm的病灶，^18F—FDG PET／CT诊断准确性明显高于增强CT（P〈0．05）。结论^18F—FDG PET／CT对诊断乳腺癌及其腋淋巴结转移的特异性均高于增强CT。     

Is 18F-FDG PET more accurate than standard diagnostic procedures in the detection of suspected recurrent melanoma?

The aim of this study was to determine the accuracy of (18)F-FDG PET in detecting recurrent melanoma. METHODS: PET findings were compared with those obtained by standard diagnostic clinical procedures (CP) to establish the role of PET in the management of patients with melanoma. From 156 patients with confirmed melanoma and recurrence suspected by clinical examination, 184 PET scans were retrospectively reviewed. Histology or clinical follow-up was used for final diagnosis. RESULTS: The sensitivity and specificity of PET for detecting lesions on an individual-patient basis were 74% and 86%, respectively, compared with respective values of 58% and 45% for CP alone. The overall accuracy for PET was 81%, compared with 52% for other methods. PET was more accurate (91% vs. 67%) than CP in detecting locoregional disease and distant metastases (85% vs. 55%), and PET results led to a change in the planned clinical management of 36% of patients included in this study. PET was more accurate than CT in detecting skin lesions, malignant lymph nodes, and metastases to the abdomen, liver, and bone. In the assessment of pulmonary disease, PET showed higher specificity (92% vs. 70%) than CT for the detection of lung parenchyma lesions; however, the sensitivity was better for CT (93%) than for PET (57%). CONCLUSION: PET is better than CP in detecting locoregional disease and distant metastases in all sites except the lung, where it appears to be a useful adjunct to CT. The use of PET as a routine clinical tool can lead to a substantial change in the clinical management of suspected recurrent melanoma.     

18F-FDG PET/CT显像在胃癌分期及治疗方案制定中的应用价值

目的探讨18F-FDG PET/CT显像在胃癌分期及治疗方案制定中的应用价值。方法回顾性分析46例临床疑诊胃癌患者的18F-FDG PET/CT图像,采用目测法和半定量法对患者PET/CT图像进行分析,即测定SUV_max与最大胃壁厚度（T_max）,以胃镜或手术后取得的病理结果作为“金标准”,评估18F-FDG PET/CT显像对病灶的诊断效能,并采用Pearson相关分析法分析SUV_max与T_max的相关性。结果18F-FDG PET/CT诊断原发病灶的灵敏度、特异度和准确率分别为94.4%、40.0%和82.6%;原发灶SUV_max与T_max呈正相关（r=0.922,P=0.001）;18F-FDG PET/CT诊断淋巴结转移及远处转移的灵敏度、特异度和准确率分别为76.9%、90.0%、82.6%和92.9%、96.9%、95.7%。结论18F-FDG PET/CT在检测胃癌的原发病灶、淋巴结转移灶和远处转移灶时有较高的特异度和灵敏度,在评估临床分期、指导临床制定正确的治疗方案中具有重要的应用价值。     

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.     

Advantages and limitations of FDG PET in the follow-up of breast cancer

18F-Fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) has been evaluated in breast cancer for the characterisation of primary tumours, lymph node staging and the follow-up of patients after surgery, chemotherapy and/or external radiotherapy. In contrast to both the low sensitivity and moderate specificity of FDG PET in the initial detection and characterisation of breast cancer and the low lesion-based sensitivity for lymph node staging, the results from use of FDG PET in re-staging breast cancer patients are very promising. A major advantage of FDG PET imaging compared with conventional imaging is that it screens the entire patient for local recurrence, lymph node metastases and distant metastases during a single whole-body examination using a single injection of activity, with a reported average sensitivity and specificity of 96% and 77%, respectively. In most studies the sensitivity of FDG PET is higher than that of a combination of conventional imaging methods. Limitations of FDG PET in the follow-up of breast cancer patients include the relatively low detection rate of bone metastases, especially in case of the sclerotic subtype, and the relatively high rate of false positive results. The rather low specificity of FDG PET can be improved/increased by utilising combined anatomical-molecular imaging techniques, such as a PET/CT tomograph. First results using PET/CT imaging in the follow-up of breast cancer patients demonstrate increased specificity compared with FDG PET alone. Both imaging modalities, however, offer to detect recurrent and metastatic breast cancer disease at an early stage and thus continue to demonstrate the efficacy of molecular imaging in patient management, despite the limited therapeutic options in recurrent and metastatic breast cancer.     

Breast cancer staging in a single session: whole-body PET/CT mammography

Our objective was to compare the diagnostic accuracy of an all-in-one protocol of whole-body 18F-FDG PET/CT and integrated 18F-FDG PET/CT mammography with the diagnostic accuracy of a multimodality algorithm for initial breast cancer staging. METHODS: Forty women (mean age, 58.3 y; range, 30.8-78.4 y; SD, 12 y) with suspected breast cancer were included. For the primary tumor, we compared 18F-FDG PET/CT mammography versus MRI mammography; for axillary lymph node status, 18F-FDG PET/CT versus clinical investigation and ultrasound; and for distant metastases, 18F-FDG PET/CT versus a multimodality staging algorithm. Histopathology and clinical follow-up served as the standard of reference. The Fisher exact test evaluated the significance of differences (P < 0.05). Alterations in patient management caused by 18F-FDG PET/CT were documented. RESULTS: No significant differences were found in the detection rate of breast cancer lesions (18F-FDG PET/CT, 95%; MRI, 100%; P = 1). 18F-FDG PET/CT correctly classified lesion focality significantly more often than did MRI (18F-FDG PET/CT, 79%; MRI, 73%; P < 0.001). MRI correctly defined the T stage significantly more often than did 18F-FDG PET/CT (MRI, 77%; 18F-FDG PET/CT, 54%; P = 0.001). 18F-FDG PET/CT detected axillary lymph node metastases in 80% of cases; clinical investigation/ultrasound, in 70%. This difference was not statistically significant (P = 0.067). Distant metastases were detected with 18F-FDG PET/CT in 100% of cases, and the multimodality algorithm identified distant metastases in 70%. This difference was not statistically significant (P = 1). Three patients had extraaxillary lymph node metastases that were detected only by PET/CT (cervical, retroperitoneal, mediastinal/internal mammary group). 18F-FDG PET/CT changed patient management in 12.5% of cases. CONCLUSION: Our data suggest that a whole-body 18F-FDG PET/CT mammography protocol may be used for staging breast cancer in a single session. This initial assessment of the 18F-FDG PET/CT protocol indicates similar accuracy to MRI for the detection of breast cancer lesions. Although MRI seems to be more accurate when assessing the T stage of the tumor, 18F-FDG PET/CT seems able to more accurately define lesion focality. Although 18F-FDG PET/CT mammography was able to detect axillary lymph node metastases with a high sensitivity, this method cannot soon be expected to replace the combination of clinical examination, ultrasound, and sentinel lymph node biopsy for axillary assessment.     

PET应用于胃癌病情评估的可行性研究

目的 探讨PET显像在胃癌病情评估中的作用。方法 将23例胃癌患者术前PET全身显像结果与手术探查、活检或胃镜检查明确的肿瘤分型、分期、转移等情况进行对照。结果 PET对胃癌原发灶的诊断准确率达87.0%。以半定量指标SUVmean和SUVmax大于2．5为诊断标准,本组PET诊断准确率分别为86．2％(19／23)和91．3％(21／23)。对淋巴结转移检测准确率为78．9%(15／19),对远处转移病灶诊断准确率为7／8。结论 PET对胃恶性肿瘤原发灶和远处转移病灶检测较为敏感,为胃癌诊断、手术方法和治疗原则的选择提供了有价值的参考依据。     

Prospective comparison of 18F-FDG PET with conventional imaging modalities (CT, MRI, US) in lymph node staging of head and neck cancer

The aims of this study were to investigate the detection of cervical lymph node metastases of head and neck cancer by positron emission tomographic (PET) imaging with fluorine-18 fluorodeoxyglucose (FDG) and to perform a prospective comparison with computed tomography (CT), magnetic resonance imaging (MRI), sonographic and histopathological findings. Sixty patients with histologically proven squamous cell carcinoma were studied by PET imaging before surgery. Preoperative endoscopy (including biopsy), CT, MRI and sonography of the cervical region were performed in all patients within 2 weeks preceding ¹⁸F-FDG whole-body PET. FDG PET images were analysed visually and quantitatively for objective assessment of regional tracer uptake. Histopathology of the resected neck specimens revealed a total of 1284 lymph nodes, 117 of which showed metastatic involvement. Based on histopathological findings, FDG PET correctly identified lymph node metastases with a sensitivity of 90% and a specificity of 94% (P<10^–6). CT and MRI visualized histologically proven lymph node metastases with a sensitivity of 82% (specificity 85%) and 80% (specificity 79%), respectively (P<10^–6). Sonography revealed a sensitivity of 72% (P<10^–6). The comparison of ¹⁸F-FDG PET with conventional imaging modalities demonstrated statistically significant correlations (PET vs CT, P = 0.017; PET vs MRI, P = 0.012; PET vs sonography, P = 0.0001). Quantitative analysis of FDG uptake in lymph node metastases using body weight-based standardized uptake values (SUV_BW) showed no significant correlation between FDG uptake (3.7±2.0) and histological grading of tumour-involved lymph nodes (P = 0.9). Interestingly, benign lymph nodes had increased FDG uptake as a result of inflammatory reactions (SUV_BW-range: 2–15.8). This prospective, histopathologically controlled study confirms FDG PET as the procedure with the highest sensitivity and specificity for detecting lymph node metastases of head and neck cancer and has become a routine method in our University Medical Center. Furthermore, the optimal diagnostic modality may be a fusion image showing the increased metabolism of the tumour and the anatomical localization. Received 17 February and in revised form 12 June 1998     

CT在术前评估卵巢恶性肿瘤淋巴结转移中的价值

目的探讨全腹CT在卵巢恶性肿瘤淋巴结转移术前评估中的价值。方法对136例原发性卵巢恶性肿瘤患者术前行全腹CT检查,并对淋巴结进行评估,根据部位将淋巴结转移分为腹腔及盆腔淋巴结转移。术后淋巴结组织病理学结果作为诊断淋巴结转移的金标准。结果术前CT诊断卵巢恶性肿瘤患者盆腹腔淋巴结转移的敏感度为47.2%,特异性为67.5%,PPV为48.08%,NPV为66.7%。CT预测盆腔淋巴结转移的敏感度为36.4%、特异性为76.7%、PPV为43.2%、NPV为71.3%。CT预测腹主动脉旁淋巴结转移的敏感度为34.6%,特异性为75.8%,PPV为52.9%,NPV为59.5%。而进一步亚组分析的敏感度等指标并没有明显提高。结论应用腹部CT检查评价卵巢恶性肿瘤是否存在淋巴结转移的准确性有限,但对肿大淋巴结定位、与周围毗邻关系有参考价值。     

The diagnostic and prognostic value of 18F-FDG PET/CT in the initial assessment of high-grade bone and soft tissue sarcoma. A retrospective study of 89 patients

Purpose

To evaluate the feasibility of ¹⁸F-FDG PET/CT for initial assessment in high-grade bone sarcomas (BS) and soft tissue sarcomas (STS).

Methods

During the years 2001–2010, 89 patients (30 BS, 59 STS) referred for further evaluation and surgical treatment of a high-grade BS or STS also had a PET/CT scan performed for staging preoperatively (n?=?68) or within 1?month of surgery (n?=?21). Metastatic lesions suggested on the PET/CT scan were confirmed or rejected by histological evaluation, by additional imaging or by follow-up. In 68 patients (28 BS, 40 STS) the relationship between the maximal standardized uptake value (SUVmax) of the primary tumour and survival was examined.

Results

The PET/CT scan suggested the presence of 13 metastatic lesions in BS patients (5 lymph node, 8 distant) and 21 metastatic lesions (6 lymph node, 15 distant) in STS patients. The calculated sensitivity (SE) and specificity (SP) were 95?% and 96?% for detection of distant metastases, and the predictive value (PV) of a positive or a negative test was 87?% and 98?%, respectively. SE and SP were 100?% and 90?% for detection of lymph node metastases, and the PV of a positive or a negative test was 27?% and 100?%, respectively. The 5-year survival was 81?% among patients with SUVmax below the median value (≤10), but was 33?% among those with SUVmax >10.

Conclusion

FDG PET/CT for the initial assessment of patients with high-grade BS or STS was feasible with high SE and SP, but in those with lymph node metastases the PV of a positive test was low. The SUVmax of the primary tumour was a strong prognostic factor for survival.     

FDG PET in detecting primary and recurrent malignant salivary gland tumors

PURPOSE: The aim of this study was to assess the role of PET in the management of patients with primary malignant salivary gland (SG) tumor. MATERIAL AND METHODS: Sixty-one FDG PET studies in 48 patients (median age 58, range 28-89 years, 20 female, 28 male) who were diagnosed with malignant SG tumors were retrospectively analyzed. Thirteen were referred for initial diagnosis and staging while there was a suspicion of recurrence and/or metastatic disease in 48 patients during the follow-up period. RESULTS: On PET examinations of 13 patients on initial presentation, 12 showed increased uptake in the primary lesion, while conventional methods (CT, MRI) were positive in 11 and were equivocal for 2 patients. Six patients with multiple nodal and 2 patients with distant metastases were detected by PET. Conventional methods demonstrated lymph node metastases in 5 of these patients. In the follow-up patient group, PET was inaccurate (false-negative or positive) in 4 (8%) patients with local recurrence, and in 4 (8%) with metastatic disease. However, 15 (31%) studies for recurrence and 7 (15%) for metastasis were false-negative with conventional radiologic methods. The sensitivity, specificity, and positive and negative predictive values for the detection of recurrent disease were 83%, 93%, 63%, and 98% for PET; 67%, 69%, 24%, and 94% for conventional methods, respectively. Overall sensitivity, specificity, positive and negative predictive values of PET for detecting metastatic disease were 93%, 96%, 82%, and 99%, while those of conventional methods were 80%, 95%, 75%, and 96%, respectively. CONCLUSION: These results demonstrate that FDG PET is not only superior to CT and/or MRI for staging at the initial presentation but also superior to conventional imaging methodologies for detecting local recurrence and regional lymph node and distant metastases in patients with malignant SG tumor.     

PET imaging in gynecologic malignancies

FDG-PET has a definite role in detecting lymph node involvement and distant metastases. It has also shown encouraging results in assessing tumor recurrence and restaging, but further studies are required before FDG-PET can be incorporated in routine clinical practice for diagnosis of recurrence. In ovarian cancer, FDG-PET has high sensitivity and specificity in identifying patients with recurrent tumor, but lesion localization is difficult with PET. Normal FDG activity in the gastrointestinal tract and bladder may obscure some lesions. Combined PET/CT can help in localizing lesions and differentiating between pathologic and physiologic uptake in the pelvis and abdomen.     

Which kinds of lymph node metastases can FDG PET detect? A clinical study in melanoma.

The purposes of this study were to establish the diagnostic accuracy of FDG PET for lymph node metastases and to determine the smallest detectable volume of disease. METHODS: Using FDG PET, we preoperatively studied 56 lymph node basins in 38 patients with a clinical or instrumental diagnosis of lymph node metastases from melanoma. All lymph node basins underwent node dissection. The FDG PET results were compared with the postoperative histopathology results. PET images were obtained using a GE 4096 WB scanner, after injection of a mean activity of 496 MBq (range, 366-699 MBq) of FDG. RESULTS: The efficacy of FDG PET in the diagnosis of involved lymph node basins was good. Sensitivity was 95% (35/37); specificity, 84% (16/19); accuracy, 91% (51/56); positive predictive value, 92% (35/38); and negative predicative value, 89% (16/18). Metastases were shown histologically in 114 of 647 surgically removed lymph nodes. FDG PET detected 100% of metastases > or = 10 mm, 83% of metastases 6-10 mm, and 23% of metastases < or = 5 mm. Moreover, FDG PET had high sensitivity (> or = 93%) only for metastases with more than 50% lymph node involvement or with capsular infiltration. CONCLUSION: Our study shows that FDG PET has a reasonable sensitivity and specificity for detecting the presence or absence of lymph node metastases in patients with melanoma. However, even if able to detect small volumes of subclinical macroscopic disease, FDG PET cannot detect subclinical microscopic disease with acceptable sensitivity. The specificity of FDG PET is good, but some false-positive results may occur.     

Tumour assessment in advanced melanoma: value of FDG-PET/CT in patients with elevated serum S-100B

Purpose To evaluate the usefulness of PET/CT in melanoma patients with an elevated serum S-100B tumour marker level. Methods Out of 165 consecutive high-risk melanoma patients referred for PET/CT imaging, 47 had elevated (>0.2 μg/l) S-100B serum levels and a contemporaneous ¹⁸F-FDG PET/CT scan. PET/CT scans were evaluated for the presence of metastases. To produce a composite reference standard, we used cytological, histological, MRI and PET/CT follow-up findings as well as clinical and S-100B follow-up. Results Among the 47 patients with increased S-100B levels, PET/CT correctly identified metastases in 38 (30 distant metastases and eight lymph node metastases). In one patient with cervical lymph node metastases, PET/CT was negative. Eight patients had no metastases and PET/CT correctly excluded metastases in all of them. Overall sensitivity for metastases was 97% (38/39), specificity 100% (8/8) and accuracy 98% (46/47). S-100B was significantly higher in patients with distant metastases (mean 1.93 μg/l, range 0.3–14.3 μg/l) than in patients with lymph node metastases (mean 0.49 μg/l, range 0.3–1.6 μg/l, p = 0.003) or patients without metastases (mean 0.625 μg/l, range 0.3–2.6 μg/l, p = 0.007). However, 6 of 14 patients with a tumour marker level of 0.3 μg/l had no metastases. Conclusion In melanoma patients with elevated S-100B tumour marker levels, FDG-PET/CT accurately identifies lymph node or distant metastases and reliably excludes metastases. Because of the significant number of false positive S-100B tumour marker determinations (17%), we recommend repetition of tumour marker measurements if elevated S-100B levels occur before extensive imaging is used.     

Diagnostic value of full-dose FDG PET/CT for axillary lymph node staging in breast cancer patients

Purpose

The aims of this study were (1) to evaluate FDG PET/CT and CT for the detection of axillary lymph node metastases in breast cancer (BC) patients and (2) to evaluate FDG PET/CT as a pre-test for the triage to sentinel lymph node biopsy (SLNB) versus axillary lymph node dissection (ALND).

Methods

The sensitivity, specificity, positive and negative predictive value (PPV, NPV), and accuracy of FDG PET/CT and CT for axillary lymph node metastases were determined in 61 patients (gold standard: histopathology). According to the equation “NPV = specificity ? (1-prevalence) / [specificity ? (1-prevalence) + (1-sensitivity) ? prevalence]” FDG PET/CT was evaluated as a triage tool for SLNB versus ALND.

Results

The sensitivity, specificity, PPV, NPV and accuracy of FDG PET/CT was 58, 92, 82, 77 and 79% and of CT 46, 89, 72, 71 and 72%, respectively. Patients with an up to ~60% risk for axillary lymph node metastases appear to be candidates for SLNB provided that the axilla is unremarkable on FDG PET/CT.

Conclusion

FDG PET/CT cannot replace invasive approaches for axillary staging but may extend the indication for SLNB.