Nasopharyngeal carcinoma staging by (18)F-fluorodeoxyglucose positron emission tomography

PURPOSE: Nasopharyngeal carcinoma (NPC) has a high rate of neck lymph node and/or distant metastasis. We evaluated the value of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in staging NPC, especially in the detection of distant metastasis. METHODS AND MATERIALS: A total of 95 patients, including 85 with primary and 10 with recurrent, NPC were enrolled. Dual-phase FDG-PET was used, in addition to the conventional workup. Eighty-one patients without distant metastases underwent repeat studies 3-4 months after initial radical treatment. RESULTS: Of 14 patients with distant metastases, all had lesions detected by FDG-PET, and the conventional workup detected the metastases in only 4. Two patients had false-positive MRI findings for neck node metastasis, but the FDG-PET findings were accurate. Four patients without distant metastases on their initial workup were found to have new lesions on FDG-PET 3-4 months after initial treatment. Patients with advanced node disease had a significantly greater incidence of distant metastases on FDG-PET, especially for N3 disease. Of the 95 patients, the FDG-PET results for distant metastasis were true positive in 14 patients, false positive in 8, and true negative in 73. None of our patients had a false-negative result. For a patient base, the sensitivity and specificity of FDG-PET for distant metastasis was 100% and 90.1% (95% confidence interval 81.5-95.6%), respectively, in this study. The accuracy was 91.6% (95% confidence interval 84.1-96.3%), the positive predictive value was 63.6 (95% confidence interval 40.7-82.8%), and the negative predictive value was 100%. CONCLUSION: FDG-PET stages N and M disease of NPC more accurately and sensitively than does the conventional workup. Patients with advanced node disease, particularly N3 disease, would benefit the most from FDG-PET.     

~(18)F-FDG PET对非小细胞肺癌预后预测价值的研究进展

目的:探讨18F-FDG PET对非小细胞肺癌预后的研究进展,指导临床中PET的应用。方法:应用计算机在PUBMED数据库检索2002~2007年有关18F-FDG PET对非小细胞肺癌预后的文章,并限定文献语种为英文,检索词fluorodeoxyglucose(FDG)、positron emmition tomography(PET)和non-small cell lung cancer和prognosis。同时,计算机检索中国期刊全文数据库2002~2007年的相关文章,检索词为PET和肺肿瘤,限定文章语言种类为中文。对选择的资料进行初审,选取和PDG-PET以及与其非小细胞肺癌预后相关的文献,然后查找全文。排除标准:1)重复研究;2)个案报道。共收集到相关文献59篇,排除重复或类似的同一研究,最终纳入30篇符合标准的文献。结果:大部分研究证明,肺癌原发灶的18F-氟脱氧葡萄糖(18F-FDG)标准摄取值(standardized uptake value,SUV)与患者的预后相关,治疗前后SUV值高的患者预后相对SUV值低的患者对放化疗敏感性差;进一步的研究显示,其复发的概率相对高,预后较差。但是放疗...     

Assessment of soft tissue lesions suspicious for liposarcoma by F18-deoxyglucose (FDG) positron emission tomography (PET)

BACKGROUND: F18-deoxyglucose (FDG) positron emission tomography (PET) is a promising imaging technique. The aim of this study was to investigate the use of FDG PET in patients with suspected liposarcomas (LS). PATIENTS AND METHODS: Forty-two masses were studied. The FDG uptake was estimated in tumor (T) and normal tissue (NT). The data were analyzed with respect to pathological findings. RESULTS: Pathology revealed 11 primary LS, 14 locally recurrent LS, 5 other sarcomas, 1 inflammation, 1 lymphoma and 10 benign lesions. FDG uptake (T-to-NT ratio) in 25 LS corresponded with the histological subtype. Pleomorphic, mixed and myxoid LS showed an increased T-to-NT ratio and were thus visualized. Four out of six well-differentiated LS presented a low FDG uptake. Like subtype, the tumor grade also corresponded to FDG uptake. The T-to-NT ratio of higher grade LS, contrary to low grade LS, was uniformly increased. Primary LS were distinguishable from benign tumors, while other sarcomas, inflammation and lymphoma were not. Recurrence was detected with a sensitivity of 86% and a specificity of 100%. False-negative diagnoses occurred only in well-differentiated recurrences. CONCLUSION: FDG uptake in LS correlates with the histological subtype and tumor grade. The diagnostic value of FDG PET in LS, therefore, is influenced by histomorphological parameters. Our data suggest that pleomorphic, mixed and higher-grade LS recurrences are preferentially amenable to FDG PET imaging.     

Evaluation of F18-deoxyglucose positron emission tomography (FDG-PET) to assess the nature of neurogenic tumours.

AIMS: Benign neurofibromas and malignant peripheral nerve sheath tumours (MPNST) commonly develop in patients with neurofibromatosis. Differentiation of benign from malignant tumours by conventional preoperative imaging is unreliable. FDG-PET is a non-invasive technique for biological tumour evaluation. The aim of this study was to assess the value of FDG-PET in patients with neurogenic tumours suspicious for MPNST. METHODS: Benign and malignant neurogenic soft tissue tumours were prospectively evaluated by computed tomography or magnetic resonance imaging. Three-dimensional qualitative and quantitative FDG-PET was performed. Standard uptake value (SUV) was analyzed with respect to histological diagnosis and follow-up data. RESULTS: Twenty-five neurogenic soft tissue tumours were included. FDG-PET identified all primary (n=6) and recurrent MPNST (n=7). Benign lesions (n=12) did not demonstrate high FDG uptake. The SUV was significantly higher in MPNST (median 2.9; range 1.8-12.3), than in benign tumours (median 1.1; range 0.5-1.8) (p<0.001). At a cut-off value of 1.8 SUV measured 1 h post-injection FDG-PET distinguished between MPNST and benign neurogenic tumours with 100% sensitivity and 83% specificity. CONCLUSIONS: FDG-PET allows discrimination of benign from malignant neurogenic tumours. This should be particularly useful in patients with neurofibromatosis as FDG-PET may help to avoid multiple surgical procedures for benign tumours.     

18F-fluoro-deoxy-glucose positron emission tomography (18F-FDG-PET) visualizes follicular lymphoma irrespective of grading.

BACKGROUND: 18F-fluoro-deoxy-glucose positron emission tomography (18F-FDG-PET) has become a routine measure for staging and follow-up of patients with aggressive lymphoma. By contrast, its usefulness to visualize indolent lymphomas characterized by a lower cellular turnover has not clearly been defined. We have investigated accuracy and clinical usefulness of 18F-FDG-PET in patients with follicular lymphoma (FL). PATIENTS AND METHODS: A total of 64 patients with FL WHO grade I - III (48, 5, and 11 patients) were imaged at our institution to assess the value of 18F-FDG-PET for imaging of FL of different gradings. A total of 115 scans (48 before therapy and 67 for response assessment after treatment) were performed, and findings were compared to conventional staging including CT-scan of thorax and abdomen, sonography of lymph nodes and bone marrow biopsy. RESULTS: Overall, 18F-FDG-PET had a sensitivity of 98%, a specificity of 94%, a positive predictive value of 95% and a negative predictive value of 98%. These results were significantly more accurate (P = 0.023) than the conventional radiology studies. There was no significant difference (P = 0.093) in the accuracy between patients with indolent (WHO grade I and II) versus aggressive FL (WHO grade III). CONCLUSION: 18F-FDG-PET scan is a reliable method for staging and follow up of patients with nodal FL irrespective of tumor grading.     

18F-FDG PET对非小细胞肺癌预后预测价值的研究进展

目的:探讨18F-FDG PET对非小细胞肺癌预后的研究进展,指导临床中PET的应用.方法:应用计算机在PUBMED数据库检索2002～2007年有关18F-FDG PET对非小细胞肺癌预后的文章,并限定文献语种为英文,检索词fluorodeoxyglucose (FDG)、positron emmition tomography (PET)和non-small cell lung cancer和prognosis.同时,计算机检索中国期刊全文数据库2002～2007年的相关文章,检索词为PET和肺肿瘤,限定文章语言种类为中文.对选择的资料进行初审,选取和PDGPET以及与其非小细胞肺癌预后相关的文献,然后查找全文.排除标准:1)重复研究;2)个案报道.共收集到相关文献59篇,排除重复或类似的同一研究,最终纳入30篇符合标准的文献.结果:大部分研究证明,肺癌原发灶的18F-氟脱氧葡萄糖(18F-FDG)标准摄取值(standardized uptake value, SUV)与患者的预后相关,治疗前后SUV值高的患者预后相对SUV值低的患者对放化疗敏感性差;进一步的研究显示,其复发的概率相对高,预后较差.但是放疗前后SUV变化能否作为独立的预后因素尚存在争议.结论:PET在非小细胞肺癌的预后判断方面有重要意义.不仅可以广泛用于放化疗疗效评价,也可用于预测肺癌治疗后复发以及对患者生存期的预测.     

18F]fluoro-deoxy-glucose positron emission tomography ([18F]FDG-PET) voxel intensity-based intensity-modulated radiation therapy (IMRT) for head and neck cancer.

BACKGROUND AND PURPOSE: Focused dose escalation may improve local control in head and neck cancer. Planning results of [(18)F]fluoro-deoxy-glucose positron emission tomography ([(18)F]FDG-PET) voxel intensity-based intensity-modulated radiation therapy (IMRT) were compared with those of PET contour-based IMRT. PATIENTS AND METHODS: PET contour-based IMRT aims to deliver a homogeneous boost dose to a PET-based subvolume of the planning target volume (PTV), called PTV(PET). The present PET voxel intensity-based planning study aims to prescribe the boost dose directly as a function of PET voxel intensity values, while leaving the dose distribution outside the PTV unchanged. Two escalation steps (2.5 and 3 Gy/fraction) were performed for 15 patients. RESULTS: PTV(PET) was irradiated with a homogeneous dose in the contour-based approach. In the voxel intensity-based approach, one or more sharp dose peaks were created inside the PTV, following the distribution of PET voxel intensity values. CONCLUSIONS: While PET voxel intensity-based IMRT had a large effect on the dose distribution within the PTV, only small effects were observed on the dose distribution outside this PTV and on the dose delivered to the organs at risk. Therefore both methods are alternatives for boosting subvolumes inside a selected PTV.     

Pitfalls of diagnosis based on abnormal flow cytometry and [(18)F]fluorodeoxyglucose positron emission tomography

A 30-year-old, HIV-positive man with a previous history of an atypical nasopharyngeal Burkitt lymphoma developed fluorodeoxyglucose (FDG) avidity on a routine FDG-positron emission tomography (PET)/computed tomography scan performed 10 months after the completion of all treatment. This new FDG-avid disease was in the area of his initial disease. Flow cytometric assessment of a fine needle aspiration showed a CD10-expressing B-cell population with kappa predominance. The corresponding cytology smears had large atypical lymphoid cells along with smaller lymphocytes and macrophages. Because of the patient's previous history of a CD10(+), high-grade B-cell lymphoma, the cytologic and flow cytometric findings were considered highly suspicious for a B-cell lymphoma. Because the differential diagnosis included a relapsed Burkitt lymphoma versus a second, unrelated lymphoma (the former with a dismal prognosis) it was deemed prudent to obtain more tissue via an open biopsy for confirmation of diagnosis and exact subclassification. An open biopsy, however, revealed a reactive lymph node with enlarged geographic follicles; no lymphoma was demonstrable and c-Myc studies were negative. The patient remains without evidence of disease. Retrospectively, the original flow cytometric assessment was believed to likely represent sampling of hyperplastic germinal centers with significantly expanded CD10(+) B cells. The FDG uptake and the kappa predominance further confounded the interpretation. This case illustrates the pitfalls of standard diagnostic techniques, including PET scanning, cytology, and flow cytometry, particularly in the setting of HIV. It further underscores the importance of adequate clinical correlation and a low threshold for performing open biopsies in such patients.     

18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) for staging and follow-up of marginal zone B-cell lymphoma

OBJECTIVE: According to recent reports, nodal marginal zone lymphoma (MZL) appears to be a distinctive lymphoma entity rather than a more advanced stage of extranodal MZL of mucosa-associated lymphoid tissue (MALT). We have therefore retrospectively evaluated all patients diagnosed with nodal or extranodal MZL who have been referred to our unit for imaging using (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET). PATIENTS AND METHODS: A total of 21 patients with a diagnosis of MZL upon referral for imaging with (18)F-FDG-PET were identified. Histological reassessment of biopsy specimens confirmed the diagnosis of extranodal MZL of MALT in 14 patients, while a diagnosis of nodal MZL was verified in 6 patients. Lymphoma cell proliferation was assessed immunohistochemically using a Ki-67 antibody. Whole-body (18)F-FDG-PET scans were performed on a GE advanced PET scanner 40 min after intravenous injection of 300-380 MBq (18)F-FDG. RESULTS: None of the patients with extranodal MZL showed focal tracer uptake within verified tumor sites. In contrast, 5 of the 6 patients with nodal MZL showed significant FDG uptake within the affected lymph nodes. These results did not simply reflect the different growth fractions of the two lymphoma entities since the proliferation indices of the two groups did not differ significantly. CONCLUSION:(18)F-FDG-PET visualizes nodal MZL in a high proportion of patients whereas FDG uptake is undetectable in extranodal MZL. Although limited by the small number of patients, this study suggests that imaging with (18)F-FDG-PET might play a potential role in the diagnostic workup of patients with nodal MZL involvement.     

18F]FDG positron emission tomography/computed tomography and multidetector computed tomography roles in thymic lesion treatment planning

RATIONALE: Thymic masses may represent an unsolved diagnostic problem which often require surgical procedures for an accurate staging. A non-invasive way to determine the nature of thymic lesions would help identify the patients which are true candidates for surgery. Our retrospective study aims to assess multidetector computed tomography and 2-[(18)F]fluoro-2-deoxyglucose positron emission tomography/computed tomography ([(18)F]FDG-PET/CT) capacity to distinguish benign from malignant thymic lesions. METHODS: Helical multidetector CT (MDCT) and [(18)F]FDG-PET/CT of twenty consecutive patients presenting with a thymic mass at our Institute were retrospectively analyzed. MDCT scans were focused on morphologic features and invasiveness characteristics. Qualitative and semi-quantitative analyses by maximum standardized uptake value corrected for body weight (SUVbw max) were performed on [(18)F]FDG-PET/CT. In all cases, readers were blinded to pathology findings. Both imaging techniques were correlated to final pathology. Student's t-test was performed on SUVbw max stratified for thymic epithelial tumors. RESULTS: In the group of benign lesions MDCT correctly identified well-defined margins of masses in 8 out of 8 patients whereas [(18)F]FDG-PET/CT was negative in 7 out of 8 patients. Among malignant lesions MDCT revealed mediastinum fat or infiltration of adjacent organs in 10/12 patients. On the other hand [(18)F]FDG-PET/CT showed increased radiotracer uptake in 12/12 patients. CONCLUSIONS: MDCT and [(18)F]FDG-PET/CT alone are not able to differentiate the nature of thymic lesions. However, they are two non-invasive complementary techniques which can be used to differentiate benign from high-risk malignant thymic lesions. These findings should be taken into account before surgery is performed as a diagnostic procedure.     

The value of [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography in extranodal natural killer/T-cell lymphoma

PurposeTo our knowledge, there are no published data pertinent to the use of [¹⁸F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in patients with natural killer (NK)/T—cell lymphoma. The purpose of this study was to assess the value of FDG PET/CT in this aggressive type of non-Hodgkin lymphoma.Patients and MethodsAll patients with NK/T-cell lymphoma referred for FDG PET/CT at our institution from July 2001 to July 2006 were retrospectively studied. PET/CT examinations were blindly reviewed by 2 experienced readers. The results were compared with the status of the disease, which was determined after evaluation of biopsy, laboratory, clinical and conventional imaging examination, and follow-up results. PET/CT results were thereby classified as true-positive, true-negative, false-positive, or false-negative. The degree of FDG uptake in the positive lesions was semiquantified using maximum standard uptake value (SUV_max).ResultsTwenty-one PET/CT examinations were performed in 10 patients with NK/T-cell lymphoma. For nasal disease, PET/CT was true-positive in 5 cases, true-negative in 15 cases, and positive but unconfirmed in 1 case. For extranasal disease, PET/CT was true-positive in 3 cases, true-negative in 16 cases, and false-negative in 2 cases. The mean SUV_max in PET-positive lesions in nasal cavities or paranasal sinuses was 16 gm/mL (range, 5–25 gm/mL; median, 19.3 gm/mL). In extranasal disease, the mean SUV_max was 10.9 gm/mL (range, 4.6–34.1 gm/mL; median, 5.6 gm/mL).ConclusionViable NK/T-cell lymphoma is intensely FDG hypermetabolic. PET/CT appears to be sensitive for the detection of disease in the nasopharynx and, to a lesser extent, in extranasal sites.     

The role of [18F]-fluorodeoxyglucose positron emission tomography in predicting plexiform neurofibroma progression

Background The role of FDG–PET for managing patients with plexiform neurofibromas (PN) is unclear. While many PN tumors exhibit periods of rapid growth, others grow slowly or unpredictably and may have periods of relative quiescence. The ability to predict which PN are likely to progress should facilitate a more timely initiation of medical treatments. Since conventional radiographic techniques have limited prognostic value, the use of a functional imaging modality to predict tumor progression is desirable. We hypothesized that PN tumors with high metabolic activity as demonstrated by FDG–PET are more likely to progress in the following year. Methods All patients were clinically stable, but were considered at high-risk for progression based on anatomical location of PN. FDG–PET scans were performed within two weeks of the baseline MRI study. Standardized uptake values (SUV) were calculated for all focally active index lesions and analyzed for correlation with changes in quantitative MRI over the ensuing year. Results Fifteen of the 18 enrolled patients showed various degrees of FDG uptake as focal abnormalities, and these abnormalities corresponded to those noted on the MRI scans. Thirteen patients and 19 lesions were evaluable for PN volume change. The SUVmax ranged from 0.9 to 4 (median 1.5). There was a significant difference in the percent increase in PN volume in the following year for lesions that had an SUV > 2 compared to those with lower values (P = 0.016). Conclusions These findings support the hypothesis that FDG–PET imaging predicts PN growth rate, and, therefore, may assist clinician decision making with regard to treatment of PN and enrollment in clinical trials.     

正电子发射断层扫描仪PET中的数据校正常用方法

介绍了正电子发射断层扫描（PET）中各种校正的意义及常见算法，这些校正包括归一化校正，衰变校正，散射与衰减校正，活度刻度等。对校正算法的最新进展和PET相关设备中的校正算法也做了些介绍。恰当的校正对提高PET的成象质量及定量分析的准确性非常重要。因此，校正算法是PET设备软件系统中所必不可少的组成部分。     

18F]fluorodeoxyglucose uptake by positron emission tomography predicts outcome of non-small-cell lung cancer.

PURPOSE: To determine whether the standardized uptake value (SUV) of [(18)F]fluorodeoxyglucose uptake by positron emission tomography could be a prognostic factor for non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: One hundred sixty-two patients with stage I to IIIb NSCLC were analyzed. Overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS), and local-regional control (LRC) were calculated by the Kaplan-Meier method and evaluated with the log-rank test. The prognostic significance was assessed by univariate and multivariate analyses. RESULTS: There were 93 patients treated with surgery and 69 patients treated with radiotherapy. A cutoff of 5 for the SUV for the primary tumor showed the best discriminative value. The SUV for the primary tumor was a significant predictor of OS (P = .02) in both groups. Low SUVs ( 5.0; surgery group, P = .02; radiotherapy group, P = .0005). Low SUVs ( 5.0; stage I or II, P = .02; stage IIIa or IIIb, P = .004). However, using the same cutoff point of 5, the SUV for regional lymph nodes was not a significant indicator for DFS (P = .19), LRC (P = .97), or DMFS (P = .17). The multivariate analysis showed that the SUV for the primary tumor was a significant prognostic factor for OS (P = .03) and DFS (P = .001). CONCLUSION: The SUV of the primary tumor was the strongest prognostic factor among the patients treated by curative surgery or radiotherapy.     

Prognostic significance of 18F-fluorodeoxyglucose positron emission tomography in lymphoma

Today, many patients with lymphoma are cured by polychemotherapy and irradiation. However, residual masses are frequently observed after treatment and discrimination between vital tumor and inactive fibrotic tissue by computed tomography or magnetic resonance tomography is often not possible. 18 F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) is a metabolic imaging modality that is able to detect active lymphoma lesions. The application of PET may play a crucial role in identifying patients with residual disease and contribute valuable prognostic information. To assess the prognostic implications of PET in the post-therapeutic setting, we performed a MedLine Search and reviewed the current available studies on this important issue together with our own data.     

18F]Fluorodeoxyglucose positron emission tomography predicts outcome for Ewing sarcoma family of tumors.

PURPOSE: Response to neoadjuvant chemotherapy is a significant prognostic factor for the Ewing sarcoma family of tumors (ESFTs). [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) is a noninvasive imaging modality that accurately predicts histopathologic response in several malignancies. To determine the prognostic value of FDG PET response for progression-free survival (PFS) in ESFTs, we reviewed the University of Washington Medical Center experience. PATIENTS AND METHODS: Thirty-six patients with ESFTs were evaluated by FDG PET. All patients received neoadjuvant and adjuvant chemotherapy. FDG PET standard uptake values before (SUV1) and after (SUV2) chemotherapy were analyzed and correlated with chemotherapy response, as assessed by histopathology in surgically excised tumors. Thirty-four patients had both SUV1 and SUV2. RESULTS: The mean SUV1, SUV2, and ratio of SUV2 to SUV1 (SUV2:1) were 7.9 (range, 2.3 to 32.8), 2.1 (range, 0 to 4.3), and 0.36 (range, 0.00 to 1.00), respectively. Good FDG PET response was defined as SUV2 less than 2.5 or SUV2:1 < or = 0.5. FDG PET response by SUV2 or SUV2:1 was concordant with histologic response in 68% and 69% of patients, respectively. SUV2 was associated with outcome (4-year PFS 72% for SUV2 < 2.5 v 27% for SUV2 > or = 2.5, P = .01 for all patients; 80% for SUV2 < 2.5 v 33% for SUV2 > or = 2.5, P = .036 for localized at diagnosis patients). SUV2:1 < or = 0.5 was not predictive of PFS. CONCLUSION: FDG PET imaging of ESFTs correlates with histologic response to neoadjuvant chemotherapy. SUV2 less than 2.5 is predictive of PFS independent of initial disease stage.