The diagnostic value of 18F-FDG PET and MRI in paediatric histiocytosis

Purpose

To analyse the diagnostic value of ¹⁸F-FDG PET and MRI for the evaluation of active lesions in paediatric Langerhans cell histiocytosis.

Methods

We compared 21 ¹⁸F-FDG PET scans with 21 MRI scans (mean time interval 17 days) in 15 patients (11 male, 4 female, age range 4 months to 19 years) with biopsy-proven histiocytosis. Primary criteria for the lesion-based analysis were signs of vital histiocyte infiltrates (bone marrow oedema and contrast enhancement for MRI; SUV greater than the mean SUV of the right liver lobe for PET). PET and MR images were analysed separately and side-by-side. The results were validated by biopsy or follow-up scans after more than 6 months.

Results

Of 53 lesions evaluated, 13 were confirmed by histology and 40 on follow-up investigations. The sensitivity and specificity of PET were 67 % and 76 % and of MRI were 81 % and 47 %, respectively. MRI showed seven false-positive bone lesions after successful chemotherapy. PET showed five false-negative small bone lesions, one false-negative lesion of the skull and three false-negative findings for intracerebral involvement. PET showed one false-positive lesion in the lymphoid tissue of the head and neck region and two false-positive bone lesions after treatment. Combined PET/MR analysis decreased the number of false-negative findings on primary staging, whereas no advantage over PET alone was seen in terms of false-positive or false-negative results on follow-up.

Conclusion

Our retrospective analysis suggests a pivotal role of ¹⁸F-FDG PET in lesion follow-up due to a lower number of false-positive findings after chemotherapy. MRI showed a higher sensitivity and is indispensable for primary staging, evaluation of brain involvement and biopsy planning. Combined MRI/PET analysis improved sensitivity by decreasing the false-negative rate during primary staging indicating a future role of simultaneous whole-body PET/MRI for primary investigation of paediatric histiocytosis.     

Guidelines for 18F-FDG PET and PET-CT imaging in paediatric oncology

OBJECTIVE: The purpose of these guidelines is to offer to the nuclear medicine team a framework that could prove helpful in daily practice. These guidelines contain information related to the indications, acquisition, processing and interpretation of (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) in paediatric oncology. The Oncology Committee of the European Association of Nuclear Medicine (EANM) has published excellent procedure guidelines on tumour imaging with (18)F-FDG PET (Bombardieri et al., Eur J Nucl Med Mol Imaging 30:BP115-24, 2003). These guidelines, published by the EANM Paediatric Committee, do not intend to compete with the existing guidelines, but rather aim at providing additional information on issues particularly relevant to PET imaging of children with cancer. CONCLUSION: The guidelines summarize the views of the Paediatric Committee of the European Association of Nuclear Medicine. They should be taken in the context of "good practice" of nuclear medicine and of any national rules, which may apply to nuclear medicine examinations. The recommendations of these guidelines cannot be applied to all patients in all practice settings. The guidelines should not be deemed inclusive of all proper procedures or exclusive of other procedures reasonably directed to obtaining the same results.     

Diagnostic value of PET/CT for the staging and restaging of pediatric tumors

Objective  The objective of this retrospective study was to compare the diagnostic value of 2-[¹⁸F]fluoro-2-deoxy-d-glucose positron emission tomography (¹⁸F-FDG PET)/CT versus ¹⁸F-FDG PET and CT alone for staging and restaging of pediatric solid tumors. Methods  Forty-three children and adolescents (19 females and 24 males; mean age, 15.2 years; age range, 6–20 years) with osteosarcoma (n = 1), squamous cell carcinoma (n = 1), synovial sarcoma (n = 2), germ cell tumor (n = 2), neuroblastoma (n = 2), desmoid tumor (n = 2), melanoma (n = 3), rhabdomyosarcoma (n = 5), Hodgkin’s lymphoma (n = 7), non-Hodgkin-lymphoma (n = 9), and Ewing’s sarcoma (n = 9) who had undergone ¹⁸F-FDG PET/CT imaging for primary staging or follow-up of metastases were included in this study. The presence, location, and size of primary tumors was determined separately for PET/CT, PET, and CT by two experienced reviewers. The diagnosis of the primary tumor was confirmed by histopathology. The presence or absence of metastases was confirmed by histopathology (n = 62) or clinical and imaging follow-up (n = 238). Results  The sensitivities for the detection of solid primary tumors using integrated ¹⁸F-FDG PET/CT (95%), ¹⁸F-FDG PET alone (73%), and CT alone (93%) were not significantly different (p > 0.05). Seventeen patients showed a total of 153 distant metastases. Integrated PET/CT had a significantly higher sensitivity for the detection of these metastases (91%) than PET alone (37%; p < 0.05), but not CT alone (83%; p > 0.05). When lesions with a diameter of less than 0.5 cm were excluded, PET/CT (89%) showed a significantly higher specificity compared to PET (45%; p < 0.05) and CT (55%; p < 0.05). In a sub-analysis of pulmonary metastases, the values for sensitivity and specificity were 90%, 14%, 82% and 63%, 78%, 65%, respectively, for integrated PET/CT, stand-alone PET, and stand-alone CT. For the detection of regional lymph node metastases, ¹⁸F-FDG PET/CT, ¹⁸F-FDG PET alone, and CT alone were diagnostically correct in 83%, 61%, and 42%. A sub-analysis focusing on the ability of PET/CT, PET, and CT to detect osseous metastases showed no statistically significant difference between the three imaging modalities (p > 0.05). Conclusion  Our study showed a significantly increased sensitivity of PET/CT over that of PET for the detection of distant metastases but not over that of CT alone. However, the specificity of PET/CT for the characterization of pulmonary metastases with a diameter > 0.5 cm and lymph node metastases with a diameter of <1 cm was significantly increased over that of CT alone.     

18F-FDG PET/CT对甲状腺结节性病变的诊断价值

目的 探讨18F-FDG PET/CT显像对于甲状腺结节性病变的诊断价值.方法 回顾性分析2008年1月至2012年5月18F-FDG PET/CT检查发现甲状腺结节性病变并有病理结果的34例患者资料,其中男13例,女21例,年龄21 ～ 73(53.00± 12.57)岁.选取20名2011年1月至2011年12月在PET/CT中心进行健康体格检查而甲状腺未发现异常者作为健康对照组,其中男9名,女11名,年龄40～55(45.00±4.72)岁.应用Wilcoxon秩和检验,分别对甲状腺良性病变和恶性病变组、良性病变和对照组及恶性病变和对照组的SUVmax进行分析,比较差异并对甲状腺结节长径行ROC曲线分析(AUC≥0.70为诊断准确性中～较高).甲状腺结节出现局限性异常放射性浓聚,而CT示病灶边界不清,内部密度不均,有点状、小圆形或弧形钙化,或同时颈部出现异常放射性浓聚的肿大淋巴结,远处器官出现可疑转移瘤者,PET/CT诊断为恶性.计算PET/CT诊断甲状腺恶性结节的效能指标.结果 (1)病理结果为恶性肿瘤18例,良性病变16例.甲状腺良、恶性组和健康对照组SUVmax分别为7.59±8.69、5.75±4.48和1.38±0.57.甲状腺良、恶性组SUVmax差异无统计学意义(u=0.207,P＞0.05),但两者与健康对照组比较差异均有统计学意义(u=3.408和3.553,均P＜0.01).(2)甲状腺良、恶性组SUVmax的ROC分析,AUC为0.557 (＜0.70),诊断准确性较低.(3)18F-FDG PET/CT诊断甲状腺良、恶性结节的灵敏度、特异性、阳性预测值、阴性预测值和准确性分别为72.2％(13/18)、75.0％(12/16)、76.5％(13/17)、70.6％(12/17)和73.5％ (25/34).结论 甲状腺结节单纯依据放射性摄取情况判断良恶性价值有限,但结合同机CT上的病灶形态学特点,18F-FDG PET/CT可以初步推测其良恶性,为临床提供客观信息.     

Diagnostic accuracy of integrated 18F-FDG PET/CT for restaging patients with malignant germ cell tumours

Objective:

Evaluation of utility of fluorine-18 fludeoxyglucose (¹⁸F-FDG) positron emission tomography/CT (PET/CT) for restaging patients with primary malignant germ cell tumours (GCTs).

Methods:

Data of 92 patients (age, 31.94 ± 10.1 years; male/female, 86/6) with histopathologically confirmed malignant GCTs (gonadal, 88; mediastinal, 4; seminomatous, 47 and non-seminomatous, 45) who underwent ¹⁸F-FDG PET/CT for restaging (suspected recurrence/post-therapy evaluation) were retrospectively analysed. Two experienced nuclear medicine physicians reviewed the PET/CT images in consensus, qualitatively and semi-quantitatively [maximum standardized uptake value (SUVmax)]. Histopathology (if available) and clinical/imaging/biochemical follow-up (minimum of 6 months) were employed as the reference standard.

Results:

¹⁸F-FDG PET/CT was interpreted as positive in 59 and negative in 33 patients. Local disease was seen in 5, nodal disease in 50 and distant metastasis in 22 patients. PET/CT was true positive in 49, false positive in 10, true negative in 30 and false negative in 3 patients. ¹⁸F-FDG PET/CT showed sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 94.2%, 75.0%, 83.0%, 90.9% and 85.8% overall; 90.0%, 74.0%, 72.0%, 90.9% and 80.8% in seminomatous GCT; and 96.8%, 76.9%, 91.1%, 90.9% and 91.1% in non-seminomatous GCT, respectively. Difference in PET/CT accuracy for seminomatous and non-seminomatous GCTs was not significant (p = 0.263). PET/CT demonstrated disease in 13 patients with negative/equivocal conventional imaging findings and in 9 patients with normal tumour markers. No site- or histology-based difference was seen in SUVmax.

Conclusion:

¹⁸F-FDG PET/CT demonstrates high diagnostic accuracy for restaging patients with malignant GCTs. It has comparable diagnostic performance in both seminomatous and non-seminomatous malignant GCTs.

Advances in knowledge:

The present article demonstrates high diagnostic accuracy of ¹⁸F-FDG PET/CT for restaging both seminomatous and non-seminomatous malignant GCTs in a large patient population.Germ cell tumour (GCT) is the commonest malignancy in males aged between 20 and 35 years.¹ With cisplatin-based chemotherapy, high long-term cure rates can be achieved in patients with GCTs.² Traditionally, the follow-up of patients with GCT is carried out with clinical examination, measurement of serum tumour markers [alpha-fetoprotein (AFP), beta-human chorionic gonadotropin (β-HCG) and lactate dehydrogenase (LDH)], and with conventional imaging investigations such as CT or MRI.³ A major issue in the management of GCTs is post-chemotherapy residual masses, which harbour viable tumour cells in about 11–37% of cases.⁴ Unfortunately, CT or MRI cannot predict the histology of residual masses and has limited specificity in post-therapy setting.⁵Fluorine-18 fludeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) improves the visualization of tumour cells by imaging their upregulated glucose metabolism. Based on this unique feature, ¹⁸F-FDG PET improves the differentiation of viable tumour from non-viable tissue.⁶ In many previous studies, ¹⁸F-FDG PET had been evaluated in patients with seminomatous and non-seminomatous GCTs with post-chemotherapy residual masses, demonstrating promising but variable results.^7–12 However, these studies had mostly employed PET alone, which suffers the limitations of having a lack of anatomical correlation, especially for detection of abdominopelvic disease, which can be overcome by the use of integrated PET/CT.¹³ Since few studies are available regarding the utility of integrated PET/CT in restaging of patients with GCTs, in the present study, this issue has been addressed. Also, since the utility of ¹⁸F-FDG PET/CT is limited for benign GCTs,¹¹ we only included patients with malignant GCTs in the present study.     

^18F-FDG PET／CT 结合 HRCT 对肺微浸润性腺癌的诊断价值

目的：^18 F-FDG PET/CT结合 HRCT 对肺微浸润性腺癌（minimally invasive adenocarcinoma ,MIA）的诊断价值。方法搜集经手术病理证实28例肺 MIA 患者的^18 F-FDG PET/CT 及 HRCT 影像资料,患者均先行^18 F-FDG PET/CT显像,后行HRCT扫描检查,分析其形态学表现及放射性分布,同时测量其SUVmax值,分析PET/CT、HRCT、PET/CT结合 HRCT三者的准确率。结果28例患者中,18 F-FDG PET 显像有19例出现高于肺本底的局灶性异常放射性摄取增高影,以SUVmax＞2．5为标准,诊断MIA的灵敏度为32．1％（9/28）。HRCT 病灶显示磨玻璃密度结节27例（96．4％）,其中单纯磨玻璃密度结节10例,混杂磨玻璃密度结节17例,单纯实性密度结节1例;病灶出现边缘分叶征18例（64．3％）,毛刺征20例（71．4％）,空泡征或支气管充气征21例（75％）,胸膜凹陷征12例（42．9％）,血管集束征10例（35．7％）,圆形结节征13例（46．4％）。PET/CT、HRCT、PET/CT结合 HRCT 三者的准确率分别为71．4％、82.1％和96．4％。结论^18 F-FDG PET/CT诊断MIA易出现假阴性,PET/CT结合HRCT有利于提高诊断准确率。     

18F-FDG PET/CT在鼻咽癌颈部淋巴结转移分期中的作用

目的 探讨18F-FDG PET/CT在鼻咽癌患者颈部淋巴结转移分期中的作用.方法 按前瞻性设计研究方案,纳入2009年3月至2010年11月病理确诊为鼻咽癌的初治患者62例,其中男48例,女14例,中位年龄43岁.患者放疗前1周内行CT或MRI检查并进行AJCC分期,然后行18FFDG PET/CT检查后再次分期.以治疗后随访6个月以上结果为标准,评价2种检查方法进行N分期的准确性.分析PET/CT N分期对治疗方案的影响,并计算Kappa值,进行一致性检验,率的比较采用x2检验.结果 62例患者中,N0 9例,N1 16例,N2 24例,N3 13例.18F-FDG PET/CT N分期准确性为96.8％(60/62),与实际N分期一致性检验Kappa值为0.955;CT或MRI N分期准确性为72.7％(45/62),Kappa值为0.607.30.6％(19/62)患者PET/CT与CT或MRI N分期不一致,随访证实PET/CT正确改变了27.4％(17/62)患者的N分期;其中l例从N0提高至N2,由根治性放疗改为放化疗综合治疗,另16例改变了转移淋巴结GTV的勾画和照射剂量.PET/CT咽后淋巴结检出率为54.8％(34/62),其灵敏度、特异性和准确性分别为80.0％ (20/25)、94.4％(17/18)和86.0％(37/43).比较43例同时有MRI和PET/CT检查结果的患者资料,两者对咽后淋巴结的检出率分别为60.5％(26/43)和55.8％ (24/43),差异无统计学意义(x2=2.000,P＞0.05).结论 18F-FDGPET/CT较常规CT或MRI对鼻咽癌N分期的准确性高,且能较好地显示咽后淋巴结,在定性较小淋巴结方面有一定优势.     

Consistency and prognostic value of preoperative staging and postoperative pathological staging using 18 F-FDG PET/MRI in patients with non-small cell lung cancer

Annals of Nuclear Medicine - In recent years, positron emission tomography/magnetic resonance imaging (PET/MRI) has been clinically used as a method to diagnose non-small cell lung cancer (NSCLC)....     

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.     

Fusion of PET and MRI for staging of uterine cervical cancer: comparison with contrast-enhanced 18F-FDG PET/CT and pelvic MRI

PurposeTo investigate the fusion of pelvic magnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography (PET) for assessment of locoregional extension and nodal staging of cervical cancer.MethodsPET/computed tomography (CT), MRI, and non-fused and fusion of PET and MRI for assessing the extent of the primary tumor and metastasis to nodes were evaluated.ResultsAccuracy for T-status was 83.3% for fused and non-fused PET/MRI and MRI proved significantly more accurate than PET/CT (53.3%) (P= .0077). Sensitivity, specificity, and accuracy for nodal metastasis were 92.3%, 88.2%, and 90.0% for fused PET/MRI and PET/contrast-enhanced CT; 84.6%, 94.1%, and 90.0% for non-fused PET/MRI; and 69.2%, 100%, and 86.7% for MRI.ConclusionFused PET/MRI combines the individual advantages of MRI and PET.     

18F-FDG PET显像诊断原发性鼻咽癌的价值

目的　探讨18F 脱氧葡萄糖 (FDG)PET显像对原发性鼻咽癌的诊断价值。方法　对 51例受检者行18F FDGPET显像 ,其中 3 1例行病理组织学检查 ,最后诊断根据病理组织学检查结果和临床随访。结果　18F FDGPET显像诊断原发性鼻咽癌的灵敏度为 96.0 0 % ,特异性为 76 92 % ,阳性预测值为 80 .0 0 % ,阴性预测值为 95 2 4% ,准确性为 86 2 7%。鼻咽癌、鼻咽炎症和无鼻咽病变组标准摄取值 (SUV)均值比较 ,3组间差异有显著性 (F =2 1 3 0 ,P <0 0 1)。结论　18F FDGPET显像诊断原发性鼻咽癌具有高灵敏度和高阴性预测值     

18F-FDG PET/CT显像对脊柱单发转移瘤的诊断价值

目的 评价18F-FDG PET/CT显像对脊柱单发转移瘤的诊断效能及优势.方法 回顾性分析67例[男41例,女26例,年龄40～83(61.5 ±10.2)岁]有恶性肿瘤病史且经局部CT和(或)MRI检查发现单个椎体病变,疑为骨转移瘤患者的资料.患者均行PET/CT显像,既往未行MRI检查者于PET/CT检查后1周内行病变椎体MRI检查.脊柱单发病灶以病理学诊断或6个月以上影像学及临床随访作为最终诊断依据,将PET/CT融合图像与单纯PET、CT及MRI图像分别对比,评价PET/CT显像对脊柱单发转移瘤的诊断效能及优势.对数据行x2检验.结果 PET/CT显像诊断脊柱单发转移瘤的灵敏度为96.3％(52/54),特异性为84.6％ (11/13),阳性预测值为96.3％(52/54),阴性预测值为84.6％ (11/13),准确性为94.0％(63/67).灵敏度、阴性预测值及准确性与PET[81.5％ (44/54)、44.4％ (8/18)、77.6％(52/67)]相比差异均有统计学意义(x2值分别为6.000、5.134、7.421,均P＜0.05);灵敏度、特异性、阴性预测值、准确性与CT[79.6％(43/54)、53.8％ (7/13)、38.9％(7/18)、74.6％(50/67)]相比差异有统计学意义(,值分别为7.083、4.248、6.482、9.543,均P＜0.05);准确性与MRI[80.6％ (54/67)]相比差异有统计学意义(x2=5.457,P＜0.05).结论 PET/CT对脊柱单发转移瘤有较高的诊断效能及优势.PET/CT准确性高于MRI,当在MRI怀疑脊柱单发转移难以明确性质时,可以通过PET/CT提高诊断准确性.     

Diagnostic and prognostic value of 18F-FDG PET/CT in recurrent germinal tumor carcinoma

Aim

The aim of this bicentric retrospective study was to assess the diagnostic performance, the prognostic value, the incremental prognostic value and the impact on therapeutic management of ¹⁸F-FDG PET/CT in patients with suspected recurrent germinal cell testicular carcinoma (GCT).

Materials and methods

From the databases of two centers including 31,500 ¹⁸F-FDG PET/CT oncological studies, 114 patients affected by GCT were evaluated in a retrospective study. All 114 patients underwent ¹⁸F-FDG PET/CT for suspected recurrent disease. Diagnostic performance of visually interpreted ¹⁸F-FDG PET/CT and potential impact on the treatment decision were assessed using histology (17 patients), other diagnostic imaging modalities (i.e., contrast enhanced CT in 89 patients and MRI in 15) and clinical follow-up (114 patients) as reference. Progression-free survival (PFS) and overall survival (OS) rates were computed by means of Kaplan-Meier survival analysis. The progression rate (Hazard Ratio-HR) was determined using univariate Cox regression analysis by considering various clinical variables.

Results

Recurrent GCT was confirmed in 47 of 52 patients with pathological ¹⁸F-FDG PET/CT findings, by means of histology in 18 patients and by other diagnostic imaging modalities/follow-up in 29. Sensitivity, specificity, accuracy, positive and negative likelihood ratio (LR+ and LR-, respectively), pre-test Odds-ratio and post-test Odds-ratio of ¹⁸FDG PET/CT were 86.8%, 90.2%, 88.4%, 8.85, 0.14, 0.85, 8.85, respectively.¹⁸F-FDG PET/CT impacted significantly on therapeutic management in 26/114 (23%) cases (from palliative to curative in 12 patients, from “wait and watch” to new chemotherapy in six patients and the “wait-and-watch” approach in eight patients with unremarkable findings). At 2 and 5-year follow-up, PFS was significantly longer in patients with a negative than a pathological ¹⁸F-FDG PET/CT scan (98% and 95% vs 48% and 38%, respectively; p = 0.02). An unremarkable scan was associated also with a longer OS (98% after 2 years and 95% after 5 years, p = 0.02). At univariate Cox regression analysis, a pathological ¹⁸F-FDG PET/CT scan was associated with an increased risk of disease progression (HR = 24.3, CI 95% 14.1-40.6; p = 0.03) and lower OS (HR = 17.3 CI 95% 4,9-77; p < 0.001). Its prognostic value was confirmed also if tested against advanced disease at diagnosis and rising Human Chorionic Gonadotropin Beta (HCGB) or Alpha-Fetoprotein (AFP) (HR = 7.3 for STAGE III-PET+, p = 0.03; HR = 14.3 elevated HCGB-PET+, p = 0.02; HR 10.7 elevated AFP-PET+, p = 0.01) At multivariate analysis, only a pathological ¹⁸F-FDG PET/CT scan and advanced disease in terms of TNM staging were predictors of disease progression and OS. ¹⁸F-FDG PET/CT showed incremental value over other variables both in predicting PFS (chi-square from 24 to 40, p < 0.001) and OS (chi-square from 32 to 38, p = 0.003).

Conclusion

¹⁸F-FDG PET/CT has a very good diagnostic performance in patients with suspected recurrent GCT and has an important prognostic value in assessing the rate of PFS and OS. Furthermore, ¹⁸F-FDG PET/CT impacted the therapeutic regimen in 23% of patients, thus providing a significant impact in the restaging process.

     

Accuracy of 18F-FDG PET/CT in detection and restaging of recurrent ovarian cancer

Purpose

To estimate the accuracy of 18FDG PET/CT in detection of recurrent cancer ovary and to describe the localization of metastases for restaging.

Diagnostic accuracy of 18F-FDG PET in restaging patients with medullary thyroid carcinoma and elevated calcitonin levels.

Medullary thyroid carcinoma (MTC) is a rare endocrine tumor arising from the C-cells of the thyroid gland. Calcitonin is the principal serum tumor marker. A rising calcitonin level after total thyroidectomy for localized disease generally indicates residual, recurrent, or metastatic disease. The role of (18)F-FDG PET in MTC remains somewhat unclear. We reviewed our own experience with (18)F-FDG PET in postthyroidectomy MTC patients with elevated calcitonin. METHODS: From our database, we identified patients with suspected residual, recurrent, or metastatic MTC and elevated calcitonin who had been referred for (18)F-FDG PET between January 2000 and October 2005. (18)F-FDG PET findings were classified as positive or negative on the basis of visual interpretation of the scan. Standardized uptake values (SUVs) were also calculated. The (18)F-FDG PET findings were verified by histopathologic examination, when available, or other imaging studies and clinical follow-up. Any negative (18)F-FDG PET result was considered false-negative. RESULTS: Twenty-eight patients underwent a total of 38 (18)F-FDG PET studies. Calcitonin levels ranged from 106 to 541,000 pg/mL (median, 7,260 pg/mL). There were 23 true-positive, 1 false-positive, and 14 false-negative (18)F-FDG PET scans, yielding an overall sensitivity of 62%. There was no true-positive finding when calcitonin levels were below 509 pg/mL (n = 5). Using an arbitrary cutoff of 1,000 pg/mL, we found that the sensitivity in scans with calcitonin levels greater than 1,000 pg/mL increased to 78% (21/27; 95% confidence interval, 58%-91%). The mean SUV of all lesions with (18)F-FDG uptake was 5.3 +/- 3.2 (range, 2.0-15.9). Among the 14 patients with false-negative (18)F-FDG PET findings, 8 had concurrent anatomic imaging studies and only 2 of these had positive findings. CONCLUSION: (18)F-FDG PET can detect residual, recurrent, or metastatic MTC with a reasonable sensitivity of 78% when the calcitonin level is above 1,000 pg/mL but appears of limited use if the calcitonin level is below 500 pg/mL.     

18F-FLT联合18F-FDG PET/CT显像对纵隔淋巴结良恶性的诊断价值

目的 评价18F-FLT联合18F-FDG PET/CT显像对肺部恶性肿瘤患者纵隔淋巴结良恶性的诊断价值.方法 回顾性分析2009年4月至2011年10月全国11个PET/CT中心18F-FLT与18 F-FDG PET/CT显像的患者资料,选择行肺部恶性肿瘤切除和纵隔淋巴结清扫、获得病理检查结果的患者共41例,其中男28例,女13例,年龄(56.1 ±12.2)岁.对18F-FLT与18F-FDG PET/CT淋巴结的显像结果分别进行视觉分析和半定量分析,采用,检验比较各方法的诊断效能.结果 (1)41例患者手术共检出533枚淋巴结,经病理检查证实恶性192枚,良性341枚(炎性增生淋巴结或正常淋巴结);(2)以18 F-FDG SUV≥2.5和18F-FLT SUV≥2.0为诊断恶性淋巴结的阈值,18F-FDG和18F-FLTPET/CT对纵隔淋巴结良恶性诊断的灵敏度、特异性、准确性、阳性预测值及阴性预测值分别为91.67％ (176/192)、80.94％ (276/341)、84.80％(452/533)、73.03％(176/241)、94.52％(276/292)和81.25％ (156/192)、92.96％(317/341)、88.74％ (473/533)、86.67％ (156/180)、89.80％ (317/353),两者灵敏度、特异性及阳性预测值差异均有统计学意义(x2=8.897、21.722和11.495,均P＜0.05),准确性和阴性预测值差异均无统计学意义(x2=3.604和3.712,均P＞0.05);18F-FDG联合18 F-FLT诊断纵隔淋巴结的灵敏度、特异性、准确性、阳性预测值及阴性预测值则分别提高至93.75％(180/192)、94.43％ (322/341)、94.18％ (502/533)、90.45％ (180/199)、96.41％(322/334).结论 18F-FDG诊断纵隔淋巴结良恶性的灵敏度高于18F-FLT,但特异性及阳性预测值明显低于FLT,两者联合诊断可明显提高诊断准确性.     

18F-FDG PET/CT delayed images after diuretic for restaging invasive bladder cancer.

PET with (18)F-FDG has been considered of limited value for detection of bladder cancer because of the urinary excretion of the tracer. The purpose of this study was to investigate the role of PET/CT in the detection and restaging of bladder cancer using furosemide and oral hydration to remove the excreted (18)F-FDG from the bladder. METHODS: Seventeen patients with bladder cancer (11 without cystectomy, 6 with total cystectomy and urinary diversion) underwent (18)F-FDG PET/CT from head to the upper thighs 60 min after the intravenous injection of 370 MBq of (18)F-FDG. Additional pelvic images were acquired 1 h after the intravenous injection of furosemide and oral hydration. PET/CT findings were confirmed by MRI, cystoscopy, or biopsy. RESULTS: PET/CT was able to detect bladder lesions in 6 of 11 patients who had not undergone cystectomy. These images changed the PET/CT final reading in 7 patients: Recurrent bladder lesions were detected in 6 patients, pelvic lymph node metastases in 2 patients, and prostate metastasis in 1. This technique overcame the difficulties posed by the urinary excretion of (18)F-FDG. Hypermetabolic lesions could be easily detected by PET and precisely localized in the bladder wall, pelvic lymph nodes, or prostate by CT. Seven of 17 patients (41%) were upstaged only after delayed pelvic images. CONCLUSION: Detection of locally recurrent or residual bladder tumors can be dramatically improved using (18)F-FDG PET/CT with delayed images after a diuretic and oral hydration.     

^18F—FDGPET／CT在肺癌肾上腺转移瘤诊断中的应用价值

目的探讨^18F-FDG PET/CT对肺癌肾上腺转移的诊断价值。方法回顾性分析在我院行^18 F-FDG PET/CT检查并诊断肾上腺转移瘤及良性病变48例肺癌患者的^18F-FDG PET/CT显像资料,分别测量肾上腺病灶（共63个）的大小（短径）、CT值及SUVmax,采用t检查及χ^2检验对各组数据进行统计学分析,采用ROC（receiver operator characteristic curve）曲线分析确定SUVmax区分肾上腺转移瘤与良性病变的最佳临界点。结果 163个病灶最终确诊46个为肾上腺转移瘤,17个为良性病变,肾上腺转移瘤与良性病变的大小分别为（2.01±1.09）cm、（1.57±0.73）cm,差异无统计学意义（t=1.472,P=0.146）;两组病灶的CT值分别为（31.69±9.98）HU、（9.80±3.98）HU,差异有统计学意义（t=7.666,P=0.000）;肾上腺转移瘤的SUVmax为8.86±5.05,良性病变的SUVmax为2.41±0.81,差异有统计学意义（t=4.889,P=0.000）。肾上腺转移瘤左右侧分布比例为：左侧50%（17/34）,右侧14.7%（5/34）,差异有统计学意义（χ^2=9.676,P=0.002）;2以肾上腺病灶SUVmax与正常肝脏的SUVmax的比值〉1作为诊断标准,PET/CT对肺癌肾上腺转移的灵敏度、特异性及准确性分别为93.5%（43/46）、76.5%（13/17）及88.9%（56/63）,阳性预测值为91.5%（43/47）,阴性预测值为81.3%（13/16）。ROC曲线分析,以SUVmax〉3.5作为诊断标准,则灵敏度、特异性、准确性、阳性预测值及阴性预测值分别为93.5%（43/46）、88.2%（15/17）、92.1%（58/63）、95.6%（43/45）,和83.3%（15/18）。结论 18F-FDG PET/CT对肺癌肾上腺转移的诊断具有较高的灵敏度、特异性及准确性;以SUVmax〉3.5作为诊断标准,可较好的诊断出肾上腺转移瘤和肾上腺良性病变。     

18F-FDG PET/CT对非小细胞肺癌术前T及N分期的价值

目的 比较^18F—FDG PET／CT与CT在非小细胞肺癌（NSCLC）原发灶（T）及淋巴结（N）分期中的价值。方法 以术后病理诊断为标准，比较30例NSCLC患者^18F-FDG PET／CT与CT在T及N分期中的诊断效能。结果 ^18F—FDG PET／CT和CT在T分期中准确性分别为86．7％，73．3％（P〉0．05）；对115站胸内淋巴结的诊断灵敏度、特异性及准确性分别为68．8％，95．2％，87．8％和43．8％，88．0％，75．7％，2种方法准确性差异有统计学意义（P〈0．05）；对65站纵隔淋巴结诊断灵敏度、特异性、准确性分别为90．5％，97．7％，95．4％和57．1％，81．8％，73．8％，2种方法准确性差异有统计学意义（P〈0．01）；在N分期中准确性分别为76．7％，66．7％（P〉0．05）。结论 ^18F—FDG PET／CT融合图像较CT更有助于NSCLC术前T和N分期，尤其在纵隔淋巴结的诊断中明显优于CT。