Imaging infection and inflammation in children with (18)F-FDG PET and (18)F-FDG PET/CT

The goal of this article is to delineate indications for (18)F-FDG PET/CT pertaining to inflammation in the pediatric population, with emphasis on those that have been described in the literature. The limitations of (18)F-FDG PET/CT in this type of evaluation are also described, and the importance of using as low a dose as feasible is discussed. After reading this article, the reader should be able to list several clinical situations in which (18)F-FDG PET/CT may be appropriate, describe some limitations of (18)F-FDG PET/CT, and explain why dose is particularly important in the pediatric population.     

18 F-FDG PET/CT显像探测原发肿瘤病灶的临床价值

目的探讨^18F-脱氧葡萄糖(FDG)PET/CT显像寻找原发肿瘤病灶的价值。方法对临床诊断转移瘤患者31例行唧CT显像，将其诊断结果与手术、活组织检查及临床随访结果对照。结果29例患者唧CT显像准确显示其原发灶，分别为结、直肠癌7例，肺癌13例，甲状腺癌3例，子宫恶性肿瘤4例，胰腺癌和鼻咽癌各1例。1例PET/CT检查未能确定其原发灶。另1例临床诊断为肾上腺转移瘤的患者，PET/CT显像为良性肿瘤，经CT动态增强检查及实验室检查证实。结论PET／CT显像对寻找转移瘤原发灶有重要价值。     

Substitution of oral (18)F-FDG for intravenous (18)F-FDG in PET scanning

The aim of this study was to see whether oral administration of (18)F-FDG could be substituted-without significant loss of information-for intravenous injection of (18)F-FDG in patients with difficult intravenous access of any cause, such as that often seen in cancer patients after many cycles of chemotherapy. METHODS: PET after both oral and intravenous administration of (18)F-FDG was performed on 2 healthy volunteers and 7 patients. An interval of 48 h was maintained between the oral administration and the intravenous administration. All scans were visually analyzed. Semiquantitative analysis of specific areas was done by calculating standardized uptake values (SUVs). Scanning was performed 60 min after intravenous tracer administration and 90 min after oral tracer administration. RESULTS: All lesions seen after intravenous administration were visualized on the oral study as well. SUVs were lower on the oral study than on the intravenous study. CONCLUSION: Oral (18)F-FDG can successfully be substituted for intravenous (18)F-FDG in patients with difficult intravenous access. However, because of the large amount of (18)F-FDG retained in the gut, careful interpretation will be required when disease of the gastrointestinal tract is being evaluated.     

18F-FDG PET/CT发现肿瘤患者意外病灶的临床价值

目的评价^18F-脱氧葡萄糖（FDG）PET／CT全身显像探测肿瘤患者意外病灶的临床价值。方法回顾性分析澳大利亚Peter MaeCallum肿瘤医院PET／CT中心2002年8月～2003年7月1727例肿瘤患者^18F—FDGPET／CT全身显像报告，男980例，女747例，中位年龄63岁，随访37个月（中位时间为27．5个月）。意外病灶指新发现的与原发肿瘤无关的良性病灶或第2原发肿瘤。通过分析病历记录、病理结果、其他影像学检查结果及临床随访，确定病灶最终结果。结果1727例患者共发现238例（13．8％）有意外病灶，其中213例220个意外病灶具有完整的随访资料。60个病灶怀疑为意外第2原发肿瘤，其中21．7％（13／60）证实为真阳性，70．0％（42／60）为假阳性，8．3％（5／60）至研究结束时未得到证实。38个甲状腺意外良性病灶，其中9个被证实为临床前恶性或恶性病灶，26个良性，3个未能证实。38个纵隔意外良性病灶，其中86．8％（33／38）证实为良性，7．9％（3／38）为原发肿瘤淋巴结侵犯，5．3％（2／38）未能证实其性质。其他部位84个意外良眭病灶，94．0％（79／84）证实为真阴性，6．0％（5／84）未能证实。共22例患者被证实存在第2原发肿瘤病灶，占本研究总人群的1．3％。结论^18F—FDGPET／CT全身显像是目前探测肿瘤患者意外病灶较好的无创方法，为制定临床治疗方案提供及时准确的依据。     

Direct comparison of (18)F-FDG PET and PET/CT in patients with colorectal carcinoma.

The purpose of this study was to compare (18)F-FDG PET and PET/CT in a population of patients with colorectal cancer. METHODS: PET and PET/CT images from 45 patients (17 women, 28 men; mean age +/- SD, 60.8 +/- 11.1 y) with known colorectal cancer referred for PET from June to November 2001 were retrospectively reviewed. Images were acquired with a PET/CT scanner, and (68)Ge attenuation correction was applied. PET images and fused (68)Ge attenuation-corrected PET and CT images were independently and separately interpreted by a moderately experienced reader unaware of the clinical information. Certainty of lesion characterization was scored on a 5-point scale (0 = definitely benign, 1 = probably benign, 2 = equivocal, 3 = probably malignant, 4 = definitely malignant). Lesion location was scored on a 3-point scale (0 = uncertain, 1 = probable, 2 = definite). The presence or absence of tumor was subsequently assessed using all available clinical, pathologic, and follow-up information. Analysis was provided for lesions detected by both PET and PET/CT. RESULTS: The frequency of equivocal and probable lesion characterization was reduced by 50% (50 to 25) with PET/CT, in comparison with PET. The frequency of definite lesion characterization was increased by 30% (84 to 109) with PET/CT. The number of definite locations was increased by 25% (92 to 115) with PET/CT. Overall correct staging increased from 78% to 89% with PET/CT on a patient-by-patient analysis. CONCLUSION: PET/CT imaging increases the accuracy and certainty of locating lesions in colorectal cancer. More definitely normal and definitely abnormal lesions (and fewer probable and equivocal lesions) were identified with PET/CT than with PET alone. Staging and restaging accuracy improved from 78% to 89%.     

The diagnostic efficacy of whole body 18F-FDG PET CT in detection of unexpected second primary malignancy in cancer patients

Purpose

to assess the efficacy of FDG PET/CT in detecting unexpected additional primary malignant neoplasms in patients being evaluated by PET/CT for known malignancies compared to conventional staging work-up (CSW).

^18F-FDG PET／CT在诊断转移性肝肿瘤中的应用

目的：探讨^18F-FDG PEF／CT在诊断转移性肝肿瘤中的应用。方法：回顾性分析49例转移性肝肿瘤患者的PET／CT影像资料,探讨^18F-FDG PET／CT诊断转移性肝肿瘤的影像表现及应用价值。结果：49例转移性肝肿瘤患者中45例^18F-FDG PET／CT表现为病灶^18F-FDG摄取明显高于周围正常肝组织;其中25例进行了延迟显像,22例表现为SUVmax及T／N值明显升高;发现肝转移同时伴有肝外转移患者38例。结论：^18F-FDG PET／CT诊断转移性肝肿瘤灵敏度高,准确,并可以同时对全身情况加以评价,对肿瘤患者肝转移的评价及治疗具有重要指导作用。     

骨转移瘤18F—FDGPET／CT影像学表现分析

目的分析骨转移瘤的18F-脱氧葡萄糖（FDG）PET／CT影像学表现。方法140例18F—FDGPET／CT检查病例,按病灶的4种CT形态（成骨改变、溶骨改变、混合改变及无改变）分组,探讨肿瘤骨转移灶代谢表现与形态表现之间的关系,进一步治疗情况与转移灶代谢表现的关系。采用SPSS10．0软件,行Mann—Whitney检验及x2检验。结果140例患者分未治疗组78例（55．7％）,治疗（化疗及内分泌）组62例（44．3％）。共检出病灶1658个,CT示成骨病灶415个（25．0％）,溶骨病灶567个（34．2％）,混合病灶177个（10．7％）,无改变病灶499个（30．1％）。对未治疗组1045个病灶平均标准摄取值（SUVmax。）行Mann—Whitney检验,混合病灶、溶骨病灶SUVmax高于成骨病灶、无改变病灶（SUVmax。中位值分别为5．7,5．2,4．8及4．6,Z=-4．680,-6．067,-2．237,-4．635,P均〈0．05）;治疗组与未治疗组行,检验,未治疗组以溶骨性改变（39．6％）为多,治疗组以成骨性改变（35．9％）为多,组间病灶组成明显不同（x2=67．8,P〈0．05）,治疗组代谢水平明显低于未治疗组（SUVmax中位值分别为4．9及4．6,Z=-4．315,P〈0．05）。结论骨转移病灶形态表现不同,其代谢表现差异明显,溶骨病灶的SUVmax。明显大于无溶骨病灶;化疗及内分泌治疗能通过对病灶转归的改变影响病灶形态及相应代谢表现。     

Usefulness of whole-body (18)F-FDG PET in patients with suspected metastatic brain tumors.

The aim of this study was to evaluate the diagnostic value of whole-body (18)F-FDG PET imaging in the differentiation of metastatic brain tumor from primary brain tumor and in the localization of the primary lesion in patients with metastatic brain tumor. METHODS: The subjects consisted of 127 patients (77 men, 50 women; mean age +/- SD, 55 +/- 12 y) with brain masses that were suspected to be metastatic brain tumors on radiologic studies: 77 with confirmed metastatic brain tumor and 50 with primary brain tumor. Whole-body (18)F-FDG PET was performed on all patients. When the abnormal lesion was detected outside the brain, we interpreted the brain lesion as metastatic brain tumor. RESULTS: In 61 of the 77 patients with metastatic brain tumor, primary lesions were detected using whole-body (18)F-FDG PET. Of the remaining 16 patients (all false-negative cases), 7 were classified as metastases of unknown origin. In 47 of the 50 patients with primary brain tumor, whole-body (18)F-FDG PET did not show any other abnormal lesions. The sensitivity, specificity, positive and negative predictive values, and accuracy of PET for the detection of primary origin were 79.2%, 94.0%, 95.3%, 74.6%, and 85.0%, respectively. The most common primary origin of metastatic brain tumors on PET examination was lung cancer (48/61, 78.7%). The concordance rate between (18)F-FDG PET and conventional radiologic work-up was 80% in identifying primary lesion. Unknown bone or bone marrow metastases and unsuspected distant metastases were found in 14 patients (18%) and 24 patients (31%), respectively, on PET examination. CONCLUSION: Screening the patients with suspected metastatic brain tumors using whole-body (18)F-FDG PET could be helpful in differentiating metastatic brain tumor from primary brain tumor and in detecting the primary lesion.     

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-FDOPA与18F-FDG PET/CT诊断脑肿瘤的系统评价

目的 系统评价18F-FDOPA与18F-FDG PET/CT显像在脑肿瘤诊断中的临床价值.方法 采用Meta分析与直接比较方法.使用计算机检索中国期刊全文数据库、中文科技期刊数据库、万方数据库、中国生物医学文献数据库、PubMed、Embase、The Cochrane Library,从建库至2016年10月,搜索直接比较18F-FDOPA与18F-FDG PET/CT诊断脑肿瘤的诊断性试验.用Meta-Disc 1.4软件进行分析,计算两种不同显像剂的合并敏感度(sensitivity,SEN)、合并特异度(specificity,SPE)、合并阳性似然比(positive likelihood ratio,+LR)、合并阴性似然比(negative likelihood ratio,-LR)、诊断优势比(diagnostic odds ratio,DOR),并绘制综合受试者工作特征曲线计算曲线下面积(area under curve,AUC)与Q*值.结果 最终共纳入4篇文章,Meta 分析结果显示,18F-FDOPA PET/CT对脑肿瘤诊断的合并SEN为0.97(95％ CI =0.90 ～ 1.00),SPE为0.67(95％ CI =0.45 ～0.84),+LR为2.31 (95％ CI=1.40 ～3.81),-LR为0.07 (95％ CI =0.02～ 0.24),DOR为39.72(95％ CI=8.94～176.48),AUC为0.9725,Q*为0.9239.18F-FDG PET/CT对脑肿瘤诊断的合并SEN为0.51(95％CI=0.39～0.63),SPE为0.75(95％ CI=0.53 ～0.90,+LR为l.59(95％ CI=0.70 ～ 3.61),-LR为0.63(95％ CI =0.47 ～0.86),DOR为2.55(95％ CI =0.82 ～7.92),AUC为0.5848,Q*为0.5638.结论 18F-FDOPA PET/CT显像诊断脑肿瘤的敏感性比18F-FDG高,对脑肿瘤具有良好的诊断价值,可作为脑肿瘤诊断的方法之一.     

Impact of 18F-FDG PET/CT on therapeutic decisions in patients with colorectal cancer and liver metastases

ObjectivesSurgical resection and radio-frequency ablation (RFA) are standard therapeutic procedures for colorectal metastases confined to the liver. The presence of extrahepatic disease has a significant effect on the management of these patients. The goal of this study is to assess the value of positron emission tomography/computed tomography with 18F-fluorodeoxyglucose (18F-FDG PET/CT) in the decision making whether to perform RFA or surgical resection of liver metastases in patients with metastatic colorectal cancer.Material and methodsThirty-five consecutive patients (23 men, 12 women; age range: 46–78 years) with colorectal carcinoma and liver metastases were prospectively enrolled. Nineteen of them were considered candidates for surgical resection and 16 for RFA. All underwent 18F-FDG PET/CT, helical computed tomography of the chest and abdomen and, some of them, magnetic resonance imaging of the abdomen. The 18F-FDG PET/CT studies were performed within 4 weeks from conventional imaging, and additional findings were later confirmed or not, either by histology or follow up.ResultsIn the surgical candidate group, 18F-FDG PET/CT detected extrahepatic disease, missed by conventional imaging, in 9/19 patients (47.3%). These findings directly altered the management in 7 patients (36.8%). In the group of RFA candidates, 18F-FDG PET/CT detected additional extrahepatic disease in 4/16 patients (25%) and directly altered management in all of them. Overall, in 11/35 patients (31.4%), 18F-FDG PET/CT detected extrahepatic metastatic disease.ConclusionIn patients with colorectal cancer and liver metastases, 18F-FDG PET/CT provides relevant additional information that has significant impact on management.     

18F-FET PET compared with 18F-FDG PET and CT in patients with head and neck cancer.

Recent studies suggest a somewhat selective uptake of O-(2-[18F]fluoroethyl)-L-tyrosine (FET) in cerebral gliomas and in squamous cell carcinoma (SCC) and a good distinction between tumor and inflammation. The aim of this study was to investigate the diagnostic potential of 18F-FET PET in patients with SCC of the head and neck region by comparing that tracer with 18F-FDG PET and CT. METHODS: Twenty-one patients with suspected head and neck tumors underwent 18F-FET PET, 18F-FDG PET, and CT within 1 wk before operation. After coregistration, the images were evaluated by 3 independent observers and an ROC analysis was performed, with the histopathologic result used as a reference. Furthermore, the maximum standardized uptake values (SUVs) in the lesions were determined. RESULTS: In 18 of 21 patients, histologic examination revealed SCC, and in 2 of these patients, a second SCC tumor was found at a different anatomic site. In 3 of 21 patients, inflammatory tissue and no tumor were identified. Eighteen of 20 SCC tumors were positive for both 18F-FDG uptake and 18F-FET uptake, one 0.3-cm SCC tumor was detected neither with 18F-FDG PET nor with 18F-FET PET, and one 0.7-cm SCC tumor in a 4.3-cm ulcer was overestimated as a 4-cm tumor on 18F-FDG PET and missed on 18F-FET PET. Inflammatory tissue was positive for 18F-FDG uptake (SUV, 3.7-4.7) but negative for 18F-FET uptake (SUV, 1.3-1.6). The SUVs of 18F-FDG in SCC were significantly higher (13.0 +/- 9.3) than those of 18F-FET (4.4 +/- 2.2). The ROC analysis showed significantly superior detection of SCC with (18)F-FET PET or 18F-FDG PET than with CT. No significant difference (P = 0.71) was found between 18F-FDG PET and 18F-FET PET. The sensitivity of 18F-FDG PET was 93%, specificity was 79%, and accuracy was 83%. 18F-FET PET yielded a lower sensitivity of 75% but a substantially higher specificity of 95% (accuracy, 90%). CONCLUSION: 18F-FET may not replace 18F-FDG in the PET diagnostics of head and neck cancer but may be a helpful additional tool in selected patients, because 18F-FET PET might better differentiate tumor tissue from inflammatory tissue. The sensitivity of 18F-FET PET in SCC, however, was inferior to that of 18F-FDG PET because of lower SUVs.     

18F-FDG PET and PET/CT for detection of pulmonary metastases from musculoskeletal sarcomas

OBJECTIVE: Sarcomas represent a significant therapeutic challenge and their potential for distant pulmonary metastases is well known. [(18)F]Fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) has a role in differentiating sarcomas from benign tumours and assessing the response to therapy in advanced sarcomas. However, PET appears to be less accurate in detection of pulmonary metastases. We were therefore prompted to review our experience with PET and PET/computed tomography (CT) in osseous and soft tissue sarcomas (OSTSs). METHODS: This is a retrospective study (January 1995 to December 2004) of 106 patients with histological diagnosis of OSTS, who had PET and PET/CT at our institution. The group included 52 men and 54 women, aged 12-92 years (average, 45+/-20 years). RESULTS: For all the patients in the analysis, the sensitivity and specificity were 68.3% (95% CI: 53-80.4) and 98.4% (95% CI: 91.8-99.7) for PET, with 95.1% sensitivity (95% CI: 83.8-98.6) and 92.3% specificity (95% CI: 83.2-96.7) for CT. Pulmonary metastases were seen in 40 patients. CT identified 17 lesions larger than 1.0 cm, while PET identified 13 of them (76.5%). CONCLUSIONS: Chest CT is more sensitive than PET in detecting pulmonary metastases from OSTS. A significant portion of known pulmonary metastases greater than 1.0 cm on CT, are PET negative. Sub-centimetre CT lesions should not be considered false positive if inactive on PET. A negative PET scan in the presence of suspicious CT findings in the chest cannot reliably exclude pulmonary metastases from OSTS.     

Utility of 18F-FDG PET(/CT) in patients with systemic and localized amyloidosis

Purpose

Amyloidosis is a group of diseases characterized by deposition of fibrils and this deposition may be localized or systemic. The presence of giant cells is typical of localized AL amyloidosis in contrast to systemic amyloidosis. Because of this presence of giant cells we hypothesize that ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) may show uptake in localized amyloidosis but not in systemic amyloidosis. The aim of the study was to evaluate the utility of ¹⁸F-FDG PET/CT in distinguishing systemic amyloidosis from localized amyloidosis.

Methods

A retrospective search in the hospital computer system showed 21 patients with histologically proven systemic or localized amyloidosis who recently had undergone ¹⁸F-FDG PET/CT. Twenty patients also had undergone ¹²³I-serum amyloid P component (SAP) scintigraphy.

Results

Of 11 patients with localized amyloidosis, 10 showed markedly increased FDG uptake at the amyloid site, whereas one showed slightly increased FDG uptake. ¹²³I-SAP scintigraphy (in ten patients) was positive in three patients at the amyloid site and negative for any other specific organ involvement in nine patients, with a weakly positive spleen in one other patient. In ten patients with systemic amyloidosis, increased FDG uptake was not found in any affected organ containing amyloid, whereas ¹²³I-SAP scintigraphy was positive for specific organ involvement in nine patients.

Conclusion

¹⁸F-FDG PET/CT may be supportive of the usual diagnostic tests in differentiating between systemic amyloidosis (no increased FDG uptake at the amyloid site) and localized amyloidosis (increased FDG uptake at the amyloid site). Apart from diagnosis, this finding has potential clinical application in therapy evaluation and follow-up.