Differential roles of 18F-FDG PET in patients with locoregional advanced nasopharyngeal carcinoma after primary curative therapy: response evaluation and impact on management.

This prospective study compares the efficacies of whole-body (18)F-FDG PET and a conventional work-up (CWU) in evaluating the treatment response for patients with locoregional advanced nasopharyngeal carcinoma (NPC) after primary curative therapy and investigates the impact of PET on patient management. METHODS: Patients who had locoregional advanced NPC (stages III and IVa-b, staged by (18)F-FDG PET and CWU) and who had completed primary curative therapy for 3 mo were enrolled. The curative therapy consisted of concurrent chemoradiotherapy with or without induction chemotherapy. All of the patients also underwent (18)F-FDG PET and CWU to evaluate the response. The criteria for final diagnosis were based on pathology or subsequent follow-up for at least 6 mo. Rates of detection by (18)F-FDG PET and CWU and the impact on management were determined on site and patient bases, respectively. RESULTS: From January 2002 to August 2005, 131 patients with NPC were eligible, including 71 patients with stage III NPC (group A) and 60 patients with stage IVa-b NPC (group B). Twelve patients were proven to have residual tumors. (18)F-FDG PET had a higher overall sensitivity than CWU in group A (100% vs. 25%) and group B (91.7% vs. 58.3%). The overall specificity of PET was significantly higher than that of CWU in group B (97.6% vs. 91.7%; P = 0.019) but was slightly lower in group A (95.7% vs. 96.7%). The overall accuracy of PET also was significantly higher than that of CWU in group B (97.2% vs. 89.4%; P = 0.002) but was similar to that of CWU in group A (95.8% vs. 95.3%). PET resulted in management changes in 11 patients (15.4%; 11/71) in group A, with positive and negative impacts on 3 and 8 patients, respectively. In group B, the management of 26 of 60 patients (43%) was changed as a result of PET and included positive impacts on 23 patients and negative impacts on 3 patients. CONCLUSION: (18)F-FDG PET plays differential roles in patients with stage III NPC and stage IVa-b NPC after primary curative therapy. PET has higher sensitivity and specificity in evaluating the response and results in better management of patients with stage IVa-b NPC. PET has a less prominent impact on patient management but higher sensitivity in patients with stage III NPC.     

18F-FDG PET and CT/MRI in oral cavity squamous cell carcinoma: a prospective study of 124 patients with histologic correlation.

Accurate evaluation of primary tumors and cervical lymph node status of squamous cell carcinoma (SCC) of the oral cavity is important to treatment planning and prognosis prediction. In this prospective study, we evaluated the use of 18F-FDG PET, CT/MRI, and their visual correlation for the identification of primary tumors and cervical nodal metastases of SCC of the oral cavity with histologic correlation. METHODS: One hundred twenty-four patients with pathologically proven diagnoses of oral cavity SCC underwent 18F-FDG PET and CT/MRI within 2 wk before surgery. We interpreted 18F-FDG PET, CT/MRI, and visually correlated 18F-FDG PET and CT/MRI separately to assess the primary tumors and their regional lymph node status. We recorded lymph node metastases according to the neck level system of imaging-based nodal classification. Histopathologic analysis was used as the gold standard for assessment of the primary tumors and lymph node involvement. We analyzed differences in sensitivity and specificity among the imaging modalities using the McNemar test. The receiver-operating-characteristic (ROC) curve and calculation of the area under the curve were used to evaluate their discriminative power. RESULTS: The accuracy of 18F-FDG PET, CT/MRI, and their visual correlation for the identification of primary tumors was 98.4%, 87.1%, and 99.2%, respectively. The sensitivity of 18F-FDG PET for the identification of nodal metastases on a level-by-level basis was 22.1% higher than that of CT/MRI (74.7% vs. 52.6%, P < 0.001), whereas the specificity of 18F-FDG PET was 1.5% lower than that of CT/MRI (93.0% vs. 94.5%, P = 0.345). The sensitivity and specificity of the visual correlation of 18F-FDG PET and CT/MRI were 3.2% and 1.5% higher than those of 18F-FDG PET alone (77.9% vs. 74.7%, P = 0.25; 94.5% vs. 93.0%, P = 0.18, respectively). The area under the curve obtained from the ROC curve showed that 18F-FDG PET was significantly superior to CT/MRI for total nodal detection (0.896 vs. 0.801, P = 0.002), whereas the visual correlation of 18F-FDG PET and CT/MRI was modestly superior to 18F-FDG PET alone (0.913 vs. 0.896, P = 0.28). CONCLUSION: 18F-FDG PET is superior to CT/MRI in the detection of cervical status of oral cavity SCC. The sensitivity of 18F-FDG PET for the detection of cervical nodal metastasis on a level-by-level basis was significantly higher than that of CT/MRI, whereas their specificities appeared to be similar. Visual correlation of 18F-FDG PET and CT/MRI showed a trend of increased diagnostic accuracy over 18F-FDG PET alone but without a statistically significant difference, and its sensitivity was still not high enough to replace pathologic lymph node staging based on neck dissection.     

18F-FDG PET can replace conventional work-up in primary M staging of nonkeratinizing nasopharyngeal carcinoma.

Conventional work-up (CWU) with chest radiography, abdominal ultrasonography, and skeletal scintigraphy has limited value in M staging of nonkeratinizing nasopharyngeal carcinoma (NPC). Our aim was to evaluate whether (18)F-FDG PET could replace CWU by comparing their diagnostic efficacies. METHODS: Patients with histologically proven nonkeratinizing NPC and no prior treatment were prospectively enrolled. All study participants underwent CWU and (18)F-FDG PET for primary M staging. Distant metastasis was considered to be present if there was any reliable evidence identified within 1 y after diagnosis. The comparative diagnostic efficacies of (18)F-FDG PET, CWU, and the combination of (18)F-FDG PET and CWU (PET+CWU) were evaluated using the areas under the receiver-operating-characteristic (ROC) curves. RESULTS: Sixty-one (20.3%) of 300 eligible patients were found to have distant metastases. On a patient-based analysis, (18)F-FDG PET was found to be more effective than CWU (P < 0.001), whereas it was equally effective with PET+CWU (P = 0.130). On region-based analyses, (18)F-FDG PET was more effective than skeletal scintigraphy and chest radiography for detecting bone metastases (P < 0.001) and chest metastases (P < 0.001), respectively. (18)F-FDG PET and abdominal ultrasound were equally effective for detecting hepatic metastases (P = 0.127). On region-based analyses, the combination of (18)F-FDG PET and CWU did not yield any noticeable increase in diagnostic efficacy. CONCLUSION: (18)F-FDG PET can replace CWU in primary M staging of nonkeratinizing NPC.     

^11C—MET和^18F—FDG PET／CT诊断胶质瘤术后残余或复发的比较

目的探讨^11C甲基蛋氨酸（MET）PET／CT对胶质瘤术后残余或复发病灶的诊断价值,并与^18F-FDG进行比较。方法46例胶质瘤术后患者均行^11C—MET和^18F-FDGPET／CT颅脑显像,2次显像间隔时间在5d内。采用ROI技术计算肿瘤与对侧灰质和白质比值。胶质瘤残余或复发病灶的诊断根据手术或立体定向活组织病理学检查、MRI、CT等影像学检查及临床随访,随访时间〉6个月。统计学比较采用z。检验或独立样本t检验。结果46例胶质瘤术后患者中残余或复发者36例。^11C-MET、^18F-FDGPET／CT显像对残余或复发病灶诊断的灵敏度分别为94．4％（34／36）、47．2％（17／36）,χ2=19．429,P〈0．001;特异性分别为90．0％（9／10）、100％（10／10）,χ2＝1．053,P〉0．05;准确性分别为93．5％（43／46）、58．7％（27／46）,χ2=15．294,P〈0．001。半定量分析：^11C—MET肿瘤／灰质比值为1．68±0．23,明显高于^18F—FDG的1．13±0．51（t=5．877,P〈0．001）,^11C—MET肿瘤／白质比值为2．52±0．28,明显高于^18F—FDG的1．42±0．57（t=10．470,P〈0．001）。结论^11C-METPET／CT显像对胶质瘤术后残余或复发病灶的诊断具有一定的临床价值,并优于^18F—FDGPET／CT显像。     

Cost-effectiveness of FDG-PET in staging non-small cell lung cancer: the PLUS study

Currently, up to 50% of the operations in early-stage non-small cell lung cancer (NSCLC) are futile owing to the presence of locally advanced tumour or distant metastases. More accurate pre-operative staging is required in order to reduce the number of futile operations. The cost-effectiveness of fluorine-18 fluorodeoxyglucose positron emission tomography ((18)FDG-PET) added to the conventional diagnostic work-up was studied in the PLUS study. Prior to invasive staging and/or thoracotomy, 188 patients with (suspected) NSCLC were randomly assigned to conventional work-up (CWU) and whole-body PET or to CWU alone. CWU was based on prevailing guidelines. Pre-operative staging was followed by 1 year of follow-up. Outcomes are expressed in the percentage of correctly staged patients and the associated costs. The cost price of PET varied between 736 and 1,588 depending on the (hospital) setting and the procurement of (18)FDG commercially or from on-site production. In the CWU group, 41% of the patients underwent a futile thoracotomy, whereas in the PET group 21% of the thoracotomies were considered futile ( P=0.003). The average costs per patient in the CWU group were 9,573 and in the PET group, 8,284. The major cost driver was the number of hospital days related to recovery from surgery. Sensitivity analysis on the cost and accuracy of PET showed that the results were robust, i.e. in favour of the PET group. The addition of PET to CWU prevented futile surgery in one out of five patients with suspected NSCLC. Despite the additional PET costs, the total costs were lower in the PET group, mainly due to a reduction in the number of futile operations. The additional use of PET in the staging of patients with NSCLC is feasible, safe and cost saving from a clinical and from an economic perspective.     

Detection of distant metastases in esophageal cancer with (18)F-FDG PET.

Standard staging of esophageal and gastroesophageal junction (GEJ) tumors substantially lacks accuracy. The aim of this study was to investigate whether the addition of PET with (18)F-FDG is a valuable gain in the initial staging. METHODS: Between January 1996 and January 2002, (18)F-FDG PET was performed in 74 patients. Conventional staging included CT in all patients and well-performed endoscopic ultrasonography (EUS) in 52 patients. They were compared with (18)F-FDG PET with pathology and follow-up of suspicious lesions as the gold standard. RESULTS: PET identified 70 primary tumors (sensitivity, 95%). Sensitivity to identify locoregional metastases was highest for EUS (69%) but was not different for CT and PET (44% and 55%, respectively). PET was able to identify distant nodal disease in 71% (17/24 patients) compared with 29% (7/24 patients) after combined CT/EUS alone (P = 0.021). Sensitivity to detect distant nodal and systemic (M1) disease increased with PET (78% vs. 37%; P = 0.012). PET upstaged 15 patients (15/74; 20%) correctly as M1 disease, missed by CT/EUS, and correctly downstaged 4 patients (5%) from M1 to M0 disease. However, false upstaging and downstaging was encountered in 5 (7%) and 3 (4%) patients, respectively. CONCLUSION: PET improves the currently applied staging of esophageal and GEJ tumors, particularly by ameliorating the detection of M1 disease.     

18F-FDG PET/CT结合MRI在癫（癎）外科治疗中的应用

目的 探讨18F-脱氧葡萄糖（FDG）PET/CT结合MRI定位致（癎）灶,指导癫（癎）外科治疗的意义.方法 67例癫（癎）外科治疗患者术前均行18F-FDG PET/CT和MRI检查,根据术前评估以及术中皮质脑电图监测结果进行致（癎）灶切除术.术后长期随访,根据Engel分级将患者分为癫（癎）发作完全控制组（Engel Ⅰ）和癫（癎）发作未完全控制组（Engel Ⅱ～Ⅳ）,采用x2检验或Fisher精确检验对数据进行分析.结果 67例中48例患者术后癫（癎）发作完全控制（Engel Ⅰ,71.6%）,11例Engel Ⅱ,5例Engel Ⅲ,3例Engel Ⅳ.18F-FDG PET/CT定位定侧结果与MRI检查结果一致或基本一致者63例,其中71.4%（45/63）术后癫（癎）发作完全控制;18F-FDG PET/CT与MRI检查结果不一致者4例,其中3例术后癫（癎）发作完全控制,2组差异无统计学意义（Fisher精确检验,P＞0.05）.63例中MRI与18F-FDG PET/CT均发现局限性异常者为41例,其中80.5%（33/41）术后癫（癎）发作完全控制;MRI发现局限性病变,但18F-FDG PET/CT呈更广泛性代谢异常者20例,其中55.0%（11/20）术后癫（癎）发作完全控制,2组差异有统计学意义（x2=4.34,P＜0.05）.结论 18F-FDG PET/CT结合MRI可为致（癎）灶定位及预后评估提供重要信息.     

Characterization of the normal adrenal gland with 18F-FDG PET/CT.

Prior studies have documented increased (18)F-FDG adrenal activity in both benign and malignant pathologic conditions. When whole-body PET imaging is performed without CT anatomic coregistration, however, the normal adrenal gland is difficult to recognize. The purpose of this study was to investigate the normal adrenal appearance and standardized uptake value (SUV) using (18)F-FDG PET/CT imaging. METHODS: Twenty patients with lymphoma with normal-appearing adrenal glands on prior CT examination (less than a 5% pretest likelihood of adrenal involvement) were studied. PET/CT imaging was performed 2 h after intravenous administration of (18)F-FDG. Unenhanced CT scans were acquired for attenuation correction and anatomic coregistration. PET images were reconstructed using an ordered-subsets expectation maximization algorithm and were corrected for body weight, dose, and radioactive decay. Ability to confirm visualization of the adrenal glands was determined for (18)F-FDG PET alone and for (18)F-FDG PET/CT by a consensus of 2 readers, and uptake of (18)F-FDG in the adrenal gland was compared with liver activity and scored visually (0 = no visualization, 1 = activity less than in liver, 2 = activity equal to liver activity, and 3 = activity greater than in liver). RESULTS: The 2 readers agreed on visualization of the adrenal glands with PET alone for 2 of 40 (5%) glands. With PET/CT, the readers agreed on visualization of 27 of 40 (68%) adrenal glands. Visual scores for normal adrenal activity ranged from 0 to 3, and maximum SUVs ranged from 0.95 to 2.46. Visual scoring of adrenal activity correlated well with both mean and maximal SUV (mean SUV vs. visual score: slope = 0.96, r = 0.88; maximum SUV vs. visual score: slope = 0.99, r = 0.87). CONCLUSION: PET/CT permits more reliable visualization of normal adrenal glands than does PET alone. Visual assessment of adrenal uptake correlates well with SUV measurement, and readers of PET/CT need to be aware of the wide range of normal adrenal uptake.     

ROC曲线评价18F—FDGPET／CT、99Tcm—MDP骨显像及二者联合对骨转移的检出效能

目的采用ROC曲线比较18F-FDGPET／CT、99TcmMDP骨显像及二者联合对骨转移患者的检出效能。方法296例恶性肿瘤患者在2个月内同时接受了18F-FDGPET／CT和99TcmMDP骨显像,对2种显像结果按5分法（0分：骨转移阴性,1分：可能阴性,2分：不能确定,3分：可能阳性,4分：肯定阳性）分别评分,两者之和为联合评分值。以病理诊断或临床随访为确诊“金标准”,采用。检验比较ROC曲线下面积,以评价骨显像、PET／CT及联合评分法对骨转移患者的检出效能,采用r检验比较不同方法在各自最佳诊断阈值下的灵敏度、特异性、准确性、阳性预测值、阴性预测值。结果296例患者中,确诊骨转移阳性61例（占20．6％）、阴性235例（占79．4％）。骨显像、PET／CT及联合评分诊断骨转移的ROC曲线下面积（95％可信区间）分别为0．919（0．867—0．971）、0．949（0．906～0．991）、0．994（0．988～0．999）,联合评分法的曲线下面积明显大于骨显像（z=2．866,P=0．004）和PET／CT（z=2．027,P=0．043）各自单独评分法,骨显像和PET／CT法曲线下面积差异没有统计学意义（z=0．881,P=0．378）。最佳阈值点下,骨显像和PET／CT单独检出骨转移患者的灵敏度、特异性、准确性、阳性预测值、阴性预测值分别为90．2％（55／61）、85．1％（200／235）、86．1％（255／296）、61．1％（55／90）、97．1％（200／206）和88．5％（54／61）、97．0％（228／235）、95．3％（282／296）、88．5％（54／61）、97．0％（228／235）,而联合评分检出的结果分别为98．4％（60／61）、95．7％（225／235）、96．3％（285／296）、85．7％（60／70）、99．6％（225／226）。PET／CT对骨转移患者检出的特异性（X2=19．600,P〈0．001）、准确性（X2=13．755,P〈0．001）、阳性预测值（x2=13．608,P〈0．001）均高于骨显像,灵敏度（r=0,P=1．000）差异无统计学意义;与骨显像、PET／CT单独评分比较,联合评分法检出的特异性（X2=19．862,P〈0．001）、准确性（x2=23．361,P〈0．001）和阳性预测值（x2=11．791,P=0．001）均明显高于骨显像,灵敏度明显高于PET／CT（x2=4．167,P=0．031）。结论18F—FDGPET／CT对骨转移患者的检出效能优于99Tcm—MDP骨显像,二者联合明显提高了对骨转移患者的检出率。     

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.     

Complementary roles of 18F-DOPA PET/CT and 18F-FDG PET/CT in medullary thyroid cancer

Serum calcitonin and carcinoembryonic antigen (CEA) are markers of recurrent or persistent disease in medullary thyroid cancer (MTC). However, conventional imaging often fails to localize metastatic disease. Our aim was to compare fluorine-labeled dihydroxyphenylalanine ((18)F-DOPA) and (18)F-FDG PET/CT with multidetector CT (MDCT) and MRI in recurrent or persistent MTC. METHODS: Nineteen MTC patients with increased calcitonin or CEA on follow-up (mean ± SD, 93 ± 91 mo; range, 4-300 mo) after primary therapy were prospectively imaged with 4 techniques: (18)F-DOPA PET/CT, (18)F-FDG PET/CT, MDCT, and MRI. Images were analyzed for pathologic lesions, which were surgically removed when possible. The correlation between the detection rate for each method and the calcitonin and CEA concentrations and histopathologic findings was investigated. Results: On the basis of histology and follow-up, one or more imaging methods accurately localized metastatic disease in 12 (63%) of 19 patients. The corresponding figures for (18)F-DOPA PET/CT, (18)F-FDG PET/CT, MDCT, and MRI were 11 (58%) of 19, 10 (53%) of 19, 9 (47%) of 19, and 10 (59%) of 17, respectively. Calcitonin and CEA correlated with (18)F-DOPA PET/CT (P = 0.0007 and P = 0.0263, respectively) and (18)F-FDG PET/CT findings (both P < 0.0001). In patients with an unstable calcitonin doubling time (n = 8), (18)F-DOPA and (18)F-FDG PET/CT were equally sensitive. In contrast, for patients with an unstable CEA doubling time (n = 4), (18)F-FDG PET/CT was more accurate. CONCLUSION: For most MTC patients with occult disease, (18)F-DOPA PET/CT accurately detects metastases. In patients with an unstable calcitonin level, (18)F-DOPA PET/CT and (18)F-FDG PET/CT are complementary. For patients with an unstable CEA doubling time, (18)F-FDG PET/CT may be more feasible. MRI is sensitive but has the highest rate of false-positive results.     

Are dual-phase 18F-FDG PET scans necessary in nasopharyngeal carcinoma to assess the primary tumour and loco-regional nodes?

Purpose This prospective study aimed to investigate the efficacy of dual-phase positron emission tomography (PET) in evaluating the loco-regional status of nasopharyngeal carcinoma (NPC).Methods Eighty-four patients with newly diagnosed NPC and a fasting serum glucose level of <200 mg/dl were enrolled. [¹⁸F]fluoro-2-deoxy-D-glucose (¹⁸F-FDG) PET studies (at 40 min and 3 h after injection of 370 MBq ¹⁸F-FDG) and head and neck magnetic resonance imaging (MRI) were performed within 1 week. Diagnostic criteria for NPC comprised the histopathological findings, the joint judgments of the research team and the post-treatment outcome. Each lesions maximum standardised uptake value (SUV) and retention index were obtained. SUV data were evaluated using a paired t test. Receiver operating characteristic curves and calculation of the area under the curve (AUC) determined the discriminative power.Results ¹⁸F-FDG PET was significantly superior to MRI in identifying lower neck NPC nodal metastasis (AUC: 1 vs 0. 972, P=0.046) and overall loco-regional metastases (AUC: 0.985 vs 0.958, P=0.036). However, ¹⁸F-FDG PET was similar to MRI in detecting primary tumour, as well as retropharyngeal, upper neck and supraclavicular nodal metastases. There was no significant difference between early phase (40 min) and delayed phase (3 h) ¹⁸F-FDG PET in the detection of primary tumours (accuracy: 100% vs 100%) or loco-regional nodal metastasis (AUC: 0.984 vs 0.985, P=0.834).Conclusion ¹⁸F-FDG PET is superior to MRI in identifying lower neck nodal metastasis of NPC. Additional 3-h ¹⁸F-FDG PET contributes no further information in the detection of primary tumours or loco-regional metastatic nodes in untreated NPC patients.     

The impact of 18F-FDG PET/CT on assessment of nasopharyngeal carcinoma at diagnosis

The aim of this study was to determine whether the use of whole-body (18)F-fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography (PET)/CT alters staging and management of nasopharyngeal carcinoma (NPC) when compared with current staging practice. 52 patients with Stage III-IV NPC without distant metastases on chest X-ray/CT, abdominal ultrasound or bone scan were recruited for the study. Whole-body (18)F-FDG PET/CT and MRI of the head and neck were performed. The scans were compared for extent of the primary tumour (PT), cervical nodal metastases (CNM) and distant metastases (DM). Any discordance in results was assessed with respect to staging and impact on management. MRI and (18)F-FDG PET/CT scans were discordant in 28 (54%) patients. There was discordance in the extent of PT at 28 sites; in all sites, MRI showed more extensive tumour involving the nasopharynx (n = 8), skull base (n = 14), brain (n = 4) and orbit (n = 2). There was also variation among the extent of CNM in four nodes of the retropharyngeal region, with the nodes being positive on MRI. (18)F-FDG PET /CT did not identify any additional distant metastases but did identify a second primary tumour in the colon. The additional use of (18)F-FDG PET/CT did not "up-stage" the overall stage or change management in any patient. In conclusion, there is discordance between MRI and (18)F-FDG PET/CT, and the additional use of (18)F-FDG PET/CT for the current assessment of NPC at diagnosis does not appear to be justified in this cohort of patients.     

Value of retrospective image fusion of F-FDG PET and MRI for preoperative staging of head and neck cancer: Comparison with PET/CT and contrast-enhanced neck MRI

Purpose

To assess the clinical value of retrospective image fusion of neck MRI and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET for locoregional extension and nodal staging of neck cancer.

Materials and methods

Thirty patients with carcinoma of the oral cavity or hypopharynx underwent PET/CT and contrast-enhanced neck MRI for initial staging before surgery including primary tumor resection and neck dissection. Diagnostic performance of PET/CT, MRI, and retrospective image fusion of PET and MRI (fused PET/MRI) for assessment of the extent of the primary tumor (T stage) and metastasis to regional lymph nodes (N stage) was evaluated.

Results

Accuracy for T status was 87% for fused PET/MRI and 90% for MRI, thus proving significantly superior to PET/CT, which had an accuracy of 67% (p = 0.041 and p = 0.023, respectively). Accuracy for N status was 77% for both fused PET/MRI and PET/CT, being superior to MRI, which had an accuracy of 63%, although the difference was not significant (p = 0.13). On a per-level basis, the sensitivity, specificity and accuracy for detection of nodal metastasis were 77%, 96% and 93% for both fused PET/MRI and PET/CT, compared with 49%, 99% and 91% for MRI, respectively. The differences for sensitivity (p = 0.0026) and accuracy (p = 0.041) were significant.

Conclusion

Fused PET/MRI combining the individual advantages of MRI and PET is a valuable technique for assessment of staging neck cancer.     

PET/CT联合高分辨超声对甲状腺偶发病灶良恶性鉴别诊断的价值

目的 探讨PET/CT联合高分辨超声(US)对甲状腺偶发病灶良、恶性的鉴别诊断价值.方法 对73个PET/CT检出的甲状腺偶发病灶病理确诊前PET/CT和US诊断意见按3分法(0分,良性可能;1分,无明确定性;2分,恶性可疑)分类,并测定病灶长径和SUVmax.以病理诊断为“金标准”,评价SUVmax、PET/CT、US、PET/CT联合US( PET/CT+US)对恶性病灶的检出效能.统计学检验包括t检验、Z检验、x2检验和Kappa一致性检验.结果 73个甲状腺偶发病灶病理确诊恶性病灶占59％(43/73),良性病灶占41％(30/73).恶性病灶SUVmax (7.0±8.1)高于良性病灶(4.1±3.8;t=2.062,P=0.043),长径小于良性病灶[(2.0±1.1) cm比(2.7±1.4) cm;t=2.628,P=0.011].SUVmax、PET/CT、US及PET/CT+ US诊断恶性病灶的ROC AUC(95％CI)分别为0.580(0.448-0.713)、0.763 (0.647～0.878)、0.905(0.826～0.983)和0.909(0.840～0.979),PET/CT AUC明显大于SUVmax(Z=2.033,P=0.042),US、PET/CT+US也明显大于PET/CT(Z值分别为1.992和2.112,P均＜0.05)和SUVmax(Z值分别为4.120和4.276,P均＜0.001).最佳阈值下,SUVmax、PET/CT、US、PET/CT+US诊断的灵敏度、特异性、准确性、阳性预测值、阴性预测值分别为42％(18/43)、83％(25/30)、59％(43/73)、78％(18/23)、50％(25/50),79％(34/43)、80％(24/30)、79％(58/73)、85％(34/40)、73％(24/33),84％(36/43)、90％(27/30)、86％(63/73)、92％(36/39)、79％(27/34)和98％(42/43)、67％(20/30)、85％(62/73)、81％(42/52)、95％(20/21).与病理诊断比较,SUV.诊断的一致性较差(Kappa=0.229,P=0.023),PET/CT的一致性中等(Kappa=0.582,P＜0.001),US和PET/CT+US的一致性好(Kappa值分别为0.668和0.674,P均＜0.001).PET/CT+US与PET/CT比较,灵敏度从79％(34/43)提高到98％(42/43),差异有统计学意义(x2=6.125,P=0.008),而特异性差异无统计学意义(从80％降低到67％;x2=2.250,P＞0.05).结论 联合高分辨US能明显提高18F-FDG PET/CT对甲状腺偶发病灶良、恶性的鉴别诊断效能.     

18F-FDG PET/CT基线SUVmax在滤泡性淋巴瘤侵袭性、分期评价中的价值及其与中期疗效的相关性研究

目的探讨18F-FDG PET/CT基线最大标准化摄取值（SUV_max）在评估滤泡性淋巴瘤（FL）侵袭性、临床分期中的应用价值及其与R-CHOP（利妥昔单抗联合环磷酰胺、阿霉素、长春新碱和泼尼松）化疗方案中期疗效的相关性。方法回顾性研究R-CHOP方案化疗前行基线18F-FDG PET/CT检查的FL患者48例,其中18例患者在3个周期R-CHOP化疗后再次行18F-FDG PET/CT检查进行疗效评估。应用两个独立样本t检验和Mann-Whitney U检验评价低级别FL组（病理分级为1~2级、3a级）与高级别FL组（病理分级为3b级及以上）、局限期组与播散期组、完全缓解组与非完全缓解组患者的基线SUV_max差异;应用Spearman相关分析评价基线SUV_max与不同Ann Arbor分期的相关性。结果低级别FL组与高级别FL组患者的基线SUV_max差异有统计学意义（6.23±4.68 vs.13.20±6.68,t=3.919,P<0.001）,受试者工作特征曲线（ROC）下面积为0.835。基线SUV_max与Ann Arbor分期无显著相关性（r=0.242,P=0.098）。低级别FL患者中局限期组的基线SUV_max明显低于播散期组,差异有统计学意义（中位数1.20 vs.7.85,U=24.000,P<0.001）,ROC曲线下面积为0.905。R-CHOP中期化疗后疗效完全缓解组的基线SUV_max明显低于非完全缓解组,差异有统计学意义（5.16±3.05 vs.10.99±7.45,t=2.172,P=0.045）。结论18F-FDG PET/CT基线SUV_max可有效评估FL的侵袭性,并与R-CHOP方案的中期疗效、低级别FL患者的病变播散程度密切相关。     

Clinical utility of 18F-FDG PET/CT in assessing the neck after concurrent chemoradiotherapy for Locoregional advanced head and neck cancer.

For patients with locoregional advanced head and neck squamous cell carcinoma (HNSCC), concurrent chemoradiotherapy is a widely accepted treatment, but the need for subsequent neck dissection remains controversial. We investigated the clinical utility of 18F-FDG PET/CT in this setting. METHODS: In this Institutional Review Board (IRB)-approved and Health Insurance Portability and Accountability Act (HIPPA)-compliant retrospective study, we reviewed the records of patients with HNSCC who were treated by concurrent chemoradiation therapy between March 2002 and December 2004. Patients with lymph node metastases who underwent 18F-FDG PET/CT > or = 8 wk after the end of therapy were included. 18F-FDG PET/CT findings were validated by biopsy, histopathology of neck dissection specimens (n = 18), or clinical and imaging follow-up (median, 37 mo). RESULTS: Sixty-five patients with a total of 84 heminecks could be evaluated. 18F-FDG PET/CT (visual analysis) detected residual nodal disease with a sensitivity of 71%, a specificity of 89%, a positive predictive value (PPV) of 38%, a negative predictive value (NPV) of 97%, and an accuracy of 88%. Twenty-nine heminecks contained residual enlarged lymph nodes (diameter, > or =1.0 cm), but viable tumor was found in only 5 of them. 18F-FDG PET/CT was true-positive in 4 and false-positive in 6 heminecks, but the NPV was high at 94%. Fifty-five heminecks contained no residual enlarged nodes, and PET/CT was true-negative in 50 of these, yielding a specificity of 96% and an NPV of 98%. Lack of residual lymphadenopathy on CT had an NPV of 96%. Finally, normal 18F-FDG PET/CT excluded residual disease at the primary site with a specificity of 95%, an NPV of 97%, and an accuracy of 92%. CONCLUSION: In patients with HNSCC, normal 18F-FDG PET/CT after chemoradiotherapy has a high NPV and specificity for excluding residual locoregional disease. In patients without residual lymphadenopathy, neck dissection may be withheld safely. In patients with residual lymphadenopathy, a lack of abnormal 18F-FDG uptake in these nodes also excludes viable tumor with high certainty, but confirmation of these data in a prospective study may be necessary before negative 18F-FDG PET/CT may become the only, or at least most-decisive, criterion in the management of the neck after chemoradiotherapy.     

18F-FLT PET/CT与18F-FDG PET/CT在鼻咽癌诊断和分期中的应用比较

目的 通过与18F-FDG PET/CT显像对比,探讨18 F-FLT PET/CT检测鼻咽癌原发灶和颈部淋巴结转移灶的可行性.方法 12例初治且经病理确诊的鼻咽癌患者(年龄22～62岁)自愿进入该前瞻性临床研究.每位患者先行18F-FDG PET/CT检查,次日行18F-FLF PET/CT检查.至少有2位核医学科和放射科医师阅片,比较18F-FDG PET/CT和18F-FLT PET/CT图像,采用ROI技术计算鼻咽肿瘤、颈部淋巴结转移灶、正常组织对18F-FDG、18F-FLT的SUVmax、SUVmean和MTV.采用非参数Wilcoxon秩和检验比较组间摄取和MTV差异.结果 12例鼻咽癌患者病灶均明显摄取18F-FLT.18F-FLT PET/CT和18F-FDG PET/CT均可准确诊断该组病例,二者对原发灶和淋巴结转移灶的检测结果无明显差别.鼻咽癌病灶的18F-FDG和18F-FLT SUVmax分别为10.7±5.8和6.0±2.4,SUVmean分别为5.8±3.0和3.6±1.5;SUVmax和SUVmean组间差异均有统计学意义(Z=-2.589和-2.353,P均＜0.05),而 MTV在18F-FDG和8F-FLT PET/CT 2种显像方法之问的差异无统计学意义(15.9±9.2和18.1±11.1;Z=-0.786,P＞0.05).6例有颈部淋巴结转移灶患者的SUVmax、SUVmean和MTV在2种显像方法间差异均无统计学意义(8.5±6.2比6.4±2.5、5.3±4.2比3.8±1.4、6.5 ±4.8比6.0±4.4;Z=-0.734、-0.734和-0.674,P均＞0.05).18F-FLT在颞叶摄取(SUVmax 0.7±0.3)明显低于18F-FDG(SUVmax 8.3±2.7;Z=-3.062,P＜0.01),其对于原发灶颅内浸润显示较18F-FDG更清晰.结论 18F-FLT PET/CT在鼻咽癌原发灶和淋巴结转移灶的诊断效能与18F-FDG PET/CT相当,对于显示原发灶的颅底附近侵犯更有利,其临床应用值得进一步研究.     

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.     

Prospective comparison of 18F-FDG PET with conventional imaging modalities (MRI, CT, and 67Ga scintigraphy) in assessment of combined intraarterial chemotherapy and radiotherapy for head and neck carcinoma.

To preserve the oral organs and functions in patients with head and neck carcinoma, accurate determination of the appropriate treatment after neoadjuvant chemotherapy and radiotherapy is of critical importance. We evaluated the diagnostic accuracy of (18)F-FDG PET relative to that of other conventional imaging modalities in the assessment of therapeutic response after combined intraarterial chemotherapy and radiotherapy as an organ preservation protocol. METHODS: The study was prospectively performed on 23 consecutive patients with head and neck squamous cell carcinoma who completed the treatment regimen and underwent 2 (18)F-FDG PET studies before and after neoadjuvant chemoradiotherapy. (67)Ga scintigraphy (only before therapy) as well as MRI and CT (both before and after therapy) were also performed. All images were blindly and independently interpreted without knowledge of histologic findings. The level of confidence in image interpretation was graded by means of a 5-point rating system (0 = definitely no tumor to 4 = definite tumor). RESULTS: Before treatment, (18)F-FDG PET detected primary tumors in all 23 patients and was more sensitive (100%) than MRI (18/23; 78.3%), CT (15/22; 68.2%), and (67)Ga scintigraphy (8/20; 40%), with a confidence level of 3 or 4 as a positive tumor finding. After chemoradiotherapy, residual tumors were histologically confirmed in 4 patients (pathologic complete response rate, 19/23; 82.6%). Although posttreatment (18)F-FDG PET showed almost equal sensitivity (4/4; 100%) compared with MRI (3/3; 100%) or CT (3/4; 75%), its specificity (17/19; 89.5%) was superior to MRI (7/17, 41.2%) and to CT (10/17; 58.8%) for primary lesions. Regarding metastases to neck lymph nodes, only specificity for posttreatment images was calculated because no metastasis was confirmed in any patients after treatment. Six subjects had (18)F-FDG PET-positive lymph nodes, which had pathologically no tumor cells and suggested an inflammatory reactive change after therapy. Therefore, the specificity of posttreatment (18)F-FDG PET (17/23; 73.9%) was almost identical to that of MRI (17/20; 85%) and CT (16/21; 76.2%) for neck metastasis. With combined chemoradiotherapy monitored with (18)F-FDG PET, 8 patients avoided surgery and the remaining 15 patients underwent a reduced form of surgery. CONCLUSION: (18)F-FDG PET facilitates differentiation of residual tumors from treatment-related changes after chemoradiotherapy, which may be occasionally difficult to characterize by anatomic images. (18)F-FDG PET has a clinical impact for the management of patients with head and neck cancers after neoadjuvant chemoradiotherapy by optimizing surgical treatment for each patient and contributes to the improvement of the patient's quality of life.