11C-蛋氨酸PET/CT显像在脑胶质瘤中的应用价值

胶质瘤是最常见的颅内原发肿瘤,其病死率及致残率均较高.常规影像学方法在脑胶质瘤的术前分级、预后判断、复发与坏死的鉴别等方面存在一定不足.PET是反映肿瘤生物学特性的一种理想的非侵入性的功能显像方法,而PET/CT则实现了功能代谢图像与解剖形态图像的同机融合,为胶质瘤的诊断提供了功能代谢信息,弥补了常规影像的不足.目前已有多种分子影像途径及示踪剂用于脑胶质瘤的定位诊断及疗效监测.其中,11C-蛋氨酸(MET)PET/CT在脑胶质瘤的诊断、分级、预后评估、浸润范围的勾画、活检计划及放疗计划的制定、放疗后坏死病灶组织和肿瘤复发的鉴别诊断等方面起到重要作用.笔者就近年来11C-MET PET/CT显像在脑胶质瘤中的应用进展做一综述.     

18F-FDG PET显像诊断肾上腺肿瘤

目的　评价1 8F 脱氧葡萄糖 (FDG)PET显像对肾上腺肿瘤的诊断价值。方法　对 2 1例肾上腺肿瘤患者共 2 2个肾上腺病灶行1 8F FDGPET显像 ,对显像结果进行定性和半定量分析 ,并与CT和 (或 )MRI、针刺活组织检查、术后病理检查结果进行对比研究。结果　 9例肾上腺病灶处无明显FDG浓集 ,PET显像诊断为良性病变 ;12例病灶处FDG明显浓集 ,诊断为恶性病变。与病理检查结果比较 ,PET显像定性准确性为 10 0 % ,CT和 (或 )MRI为 6 4 %。良性病变与周围正常组织 (T N)放射性比值为 0 3～ 1 3,平均为 0 7,标准摄取值 (SUV)为 0 98～ 3 89,平均为 1 89;恶性病变T N比值为 3 1～15 1,平均为 6 9,SUV为 3 10～ 15 5 2 ,平均为 6 4 1,两组间差异均有显著性 (P均 <0 0 0 1)。病变性质与肿块大小无相关性。其中 4例PET显像发现了CT和 (或 )MRI未发现的局部淋巴结和远处转移灶12处。结论　1 8F FDGPET显像对肾上腺肿瘤定性诊断的准确性明显高于CT和 (或 )MRI。     

18F-FDG和18F-FET PET脑显像诊断垂体腺瘤

目的 比较^18F-脱氧葡萄糖(FDG)和^18F-酪氨酸(FET)PET显像对垂体腺瘤的诊断价值。方法 正常对照者7例同期行^18F-FDGPET脑显像和^13N-NH3PET脑血流显像。20例垂体腺瘤患者行^18F-FDG PET脑显像，其中10例同期行^18F-FETPET脑显像，并参照近期MRI结果进行分析。加例患者均行经口鼻蝶窦垂体腺瘤切除术，术后行病理检查及免疫组织化学分型。结果①正常对照组垂体^18F-FDG摄取明显低于周围组织。②对于分泌激素和无分泌功能的垂体腺瘤，^18F-FDGPET和^18F-FETPET均可显示病灶。③垂体腺瘤在^18F-FDG显像中多表现为均匀的放射性摄取增高，而^18F-FET。显像则多表现为散在的摄取增高，与MRI所示等瓦长T2或稍长瓦长T2信号的肿瘤组织分布相似。④7例微腺瘤^18F-FDG PET检出5例，MRI检出3例。⑤不同激素分泌型和无分泌功能垂体腺瘤的瘤体大小、激素水平与^18F-FDG或^18F-FET显像标准摄取值(SUV)间无明显相关。结论 ^18F-FDG和^18F-FET PET脑显像均可显示垂体腺瘤,而以前者更佳。     

11C-蛋氨酸PET/CT显像在脑胶质瘤中的初步应用

目的探讨11C-蛋氨酸(MET)PET/CT显像对脑胶质瘤的应用价值.方法2例正常对照者、2例脑胶质瘤初诊患者和23例脑胶质瘤术后患者行11C-MET PET/CT显像;25例患者中有17例同时行18F-脱氧葡萄糖(FDG)PET/CT显像.临床随访时间3～17个月.结果4例脑胶质瘤术后无肿瘤残余或复发者11C-MET显像为阴性,其中3例同时行18F-FDG显像也为阴性.2例胶质瘤Ⅱ级初诊者和19例脑胶质瘤术后残余、复发者中,20例11C-MET显像阳性(肿瘤/灰质、肿瘤/白质比值分别为2.02±0.96、3.01±1.79),其中14例同时行18F-FDG显像中12例为阳性.11C-MET显像所见病灶远较18F-FDG显像清晰.14例患者11C-MET、18F-FDG显像的肿瘤/灰质、肿瘤/白质比值分别为2.15±1.16比0.97±0.43(P＜0.01)、3.31±2.16比1.90±0.67(P＜0.05).结论11C-MET对脑胶质瘤的显像、定位优于18F-FDG.     

^(18)F-FDOPA PET显像在脑胶质瘤中的临床应用价值

脑胶质瘤是发病率最高的神经系统来源肿瘤。目前临床上诊断胶质瘤的方法主要为MRI平扫及增强,但存在一定的局限性。近年来,随着PET与核素显像剂的不断发展和改进,其在胶质瘤领域的研究越来越深入,尤其是18F-FDOPA PET显像在原发性及复发性胶质瘤的诊断、鉴别、分级、定位、治疗和预后评估中具有较高的临床应用价值。本文就此进行综述。     

PET在颅内胶质瘤术后放射治疗后随访中的应用价值

目的：探讨PET在颅内胶质瘤术后,放射治疗后随诊中的作用。方法：对16例颅内胶质瘤术事并放射治疗后的病例采用双盲法将PET与CT／或MRI结果进行比较。结果：16例中14例（占87．5％）CT和／或MRI表现不规则环形或结节状明显强化,不能准确作出手术后改变和／或放射治疗后脑损伤,残存肿瘤或神经复发的诊断;其中9例残存肿瘤或肿瘤复发病灶^18F-FDG PET影像均表现为葡萄糖代谢率明显增高,另5例术后放射治疗后脑损伤病例和2例术后软化灶^18F-FDG PET影像均显示局部病变区为放射性分布缺损或明显低下。结论：与CT和MRI相比,PET在胶质瘤术后放射治疗后的脑损伤和肿瘤复发的定性诊断上具有明显的优势,若结合CT和MRI多种影像结果分析,更能提供病变解剖结构和功能改变的综合信息,尤其是对胶质瘤术后放射治疗后的临床随访非常重要。     

PET/MR在心血管疾病中的应用进展

PET/MR作为新型的多模态成像技术,集合了MRI高软组织对比度、多序列、多参数、可定量和PET多分子探针显像的高灵敏度的优势,实现了PET分子功能影像与具有精细解剖结构和组织特征的MRI影像同步扫描,在多种心血管疾病中的应用和研究越来越广泛。笔者总结PET/MR心血管成像的优点和局限性,并探讨其在临床中的主要应用。     

IDH突变和1p/19q联合缺失型脑胶质瘤的影像学研究进展

【摘要】异柠檬酸脱氢酶（IDH）突变和染色体1p/19q联合缺失是脑胶质瘤的重要分子生物学标志物,与脑胶质瘤的诊断、治疗及预后密切相关。目前,多模态MRI、PET/CT等影像学检查能获取反映脑胶质瘤结构、功能、代谢及分子水平改变的重要信息,影像组学也可通过提取图像特征来反映肿瘤表型,极大地改变了对胶质瘤诊断、预后和治疗计划的认识。本文就IDH突变和1p/19q联合缺失型脑胶质瘤的影像学研究进展予以综述。     

18F-FDG PET在肿瘤诊断和治疗中的应用

正电子发射断层显像(positronemissiontomography,PET)是当今影像学领域最先进的技术之一,代表了现代核医学影像技术的最高水平。近些年,PET临床应用最重要的方面是在肿瘤学中的应用。不同于CT、MRI,PET显像是从分子水平反映肿瘤组织中的生化改变和代谢现象[1]。本文概述了近年     

多种不同PET或PET／CT分子探针在胶质瘤中的应用进展

胶质瘤是一种发病率最高的中枢神经系统原发性肿瘤,约占颅内肿瘤的40％～50％,其恶性程度及病死率极高,加之病理学类型多样、生物学行为各异,胶质瘤对各种治疗手段的反应也是不尽相同的。胶质瘤预后凶险,尤其是高级别胶质瘤。CT是一种以组织密度差异来反映局部解剖结构的影像学检查方法,它能清晰地显示组织结构,但不能反映肿瘤的代谢状况。MRI虽然具有良好的组织分辨率,也能从一定程度上反映肿瘤的代谢状况,但依然具有一定的局限性。PET及PET／CT是一种相对而言比较新兴的检查方法,主要反映肿瘤的代谢状况,随着mF．FDGPET或PET／CT的广泛应用,以及各种非FDG显像剂的发展,PET或PET／CT在胶质瘤诊断中的应用将越来越受到重视。     

Clinical applications of PET in brain tumors.

Malignant gliomas and metastatic tumors are the most common brain tumors. Neuroimaging plays a significant role clinically. In low-grade tumors, neuroimaging is needed to evaluate recurrent disease and to monitor anaplastic transformation into high-grade tumors. In high-grade and metastatic tumors, the imaging challenge is to distinguish between recurrent tumor and treatment-induced changes such as radiation necrosis. The current clinical gold standard, MRI, provides superior structural detail but poor specificity in identifying viable tumors in brain treated with surgery, radiation, or chemotherapy. (18)F-FDG PET identifies anaplastic transformation and has prognostic value. The sensitivity and specificity of (18)F-FDG in evaluating recurrent tumor and treatment-induced changes can be improved significantly by co-registration with MRI and potentially by delayed imaging 3-8 h after injection. Amino acid PET tracers are more sensitive than (18)F-FDG in imaging recurrent tumors and in particular recurrent low-grade tumors. They are also promising in differentiating between recurrent tumors and treatment-induced changes.     

18F-fluoro-L-thymidine and 11C-methylmethionine as markers of increased transport and proliferation in brain tumors.

Because of the high glucose metabolism in normal brain tissue 18F-FDG is not the ideal tracer for the detection of gliomas. Methyl-11C-l-methionine (11C-MET) is better suited for imaging the extent of gliomas, because it is transported specifically into tumors but only insignificantly into normal brain. 3'-Deoxy-3'-18F-fluorothymidine (18F-FLT) has been introduced as a proliferation marker in a variety of neoplasias and has promising potential for the detection of brain tumors, because its uptake in normal brain is low. Additionally, the longer half-life might permit differentiation between transport and intracellular phosphorylation. METHODS: PET of 18F-FLT and 11C-MET was performed on 23 patients (age range, 20-70 y) with histologically verified gliomas of different grades. On all patients, conventional MRI was performed, and 16 patients additionally underwent contrast-enhanced imaging. Images were coregistered, and the volumes of abnormality were defined for PET and MRI. Uptake ratios and standardized uptake values (SUVs) of various tumors and regions were assessed by region-of-interest analysis. Kinetic modeling was performed on 14 patients for regional time-activity curves of 18F-FLT from tumorous and normal brain tissue. RESULTS: Sensitivity for the detection of tumors was lower for 18F-FLT than for 11C-MET (78.3% vs. 91.3%), especially for low-grade astrocytomas. Tumor volumes detected by 18F-FLT and 11C-MET were larger than tumor regions displaying gadolinium enhancement (P<0.01). Uptake ratios of 18F-FLT were higher than uptake ratios of 11C-MET (P<0.01). Uptake ratios of 18F-FLT were higher in glioblastomas than in astrocytomas (P<0.01). Absolute radiotracer uptake of 18F-FLT was low and significantly lower than that of 11C-MET (SUV, 1.3+/-0.7 vs. 3.1+/-1.0; P<0.01). Some tumor regions were detected only by either 18F-FLT (7 patients) or 11C-MET (13 patients). Kinetic modeling revealed that 18F-FLT uptake in tumor tissue seems to be predominantly due to elevated transport and net influx. However, a moderate correlation was found between uptake ratio and phosphorylation rate k3 (r=0.65 and P=0.01 for grade II-IV gliomas; r=0.76 and P<0.01 for grade III-IV tumors). CONCLUSION: 18F-FLT is a promising tracer for the detection and characterization of primary central nervous system tumors and might help to differentiate between low- and high-grade gliomas. 18F-FLT uptake is mainly due to increased transport, but irreversible incorporation by phosphorylation might also contribute. In some tumors and tumor areas, 18F-FLT uptake is not related to 11C-MET uptake. In view of the high sensitivity and specificity of 11C-MET PET for imaging of gliomas, it cannot be excluded that 18F-FLT PET was false positive in these areas. However, the discrepancies observed for the various imaging modalities (18F-FLT and 11C-MET PET as well as gadolinium-enhanced MRI) yield complementary information on the activity and the extent of gliomas and might improve early evaluation of treatment effects, especially in patients with high-grade gliomas. Further studies are needed, including coregistered histology and kinetic analysis in patients undergoing chemotherapy.     

Usefulness of semiquantitative FDG-PET in the prediction of brain tumor treatment response to gamma knife radiosurgery

PURPOSE: The aim of this study is to evaluate whether posttreatment FDG-PET can predict the treatment response to gamma knife radiosurgery (GKRS) for patients with gliomas. METHOD: Eighteen patients with histologically confirmed gliomas treated by GKRS and followed for more than 24 months were enrolled in this study. All patients underwent FDG-PET 6-8 months after GKRS. PET images and MR images were integrated and tumor-to-cortex (T/C) and tumor-to-white matter (T/WM) FDG uptake ratios were measured. By estimating the change of the maximum tumor diameter measured on the contrast-enhanced MRI (the last follow-up MRI vs. the pre-GKRS MRI), the tumor response was classified as complete remission, partial remission (PR), stable disease (SD), and progression of disease (PD). Group 1 includes four tumors with PR and 6 tumors with SD; group 2 includes 8 tumors with PD after GKRS. RESULTS: Both mean T/C ratio and mean T/WM ratio of group 1 patients are statistically less than those of group 2 patients. CONCLUSION: Our study suggests that, for patients with gliomas treated by GKRS, the posttreatment FDG-PET may be useful to predict the treatment response.     

11C-CHO PET in optimization of target volume delineation and treatment regimens in postoperative radiotherapy for brain gliomas

ObjectiveWe explored the clinical values of ¹¹C-choline (¹¹C-CHO) PET in optimization of target volume delineation and treatment regimens in postoperative radiotherapy for brain gliomas.MethodsSixteen patients with the pathological confirmation of the diagnosis of gliomas prior to receiving radiotherapy (postoperative) were included, and on whom both MRI and CHO PET scans were performed at the same position for comparison of residual tumors with the two techniques. ¹¹C-CHO was used as the tracer in the PET scan. A plain T1-weighted, T2-weighted and contrast-enhanced T1-weighted imaging scans were performed in the MRI scan sequence. The gliomas' residual tumor volume was defined as the area with CHO-PET high-affinity uptake and metabolism (V_CHO) and one with MRI T1-weighted imaging high signal intensity (V_Gd), and was determined by a group of experienced professionals and clinicians.Results(1) In CHO-PET images, the tumor target volume, i.e., the highly metabolic area with a high concentration of isotopes (SUV 1.016–4.21) and the corresponding contralateral normal brain tissues (SUV0.1–0.62), was well contrasted, and the boundary between lesions and surrounding normal brain tissues was better defined compared with MRI and ¹⁸F-FDG PET images. (2) For patients with brain gliomas of WHO Grade II, the SUV was 1.016–2.5; for those with WHO Grades III and IV, SUVs were >26–4.2. (3) Both CHO PET and MRI were positive for 10 patients and negative for 2 patients. The residual tumor consistency between these two studies was 75%. Four of the 10 CHO-PET-positive patients were negative on MRI scans. The maximum distance between V_Gd and V_CHO margins was 1.8 cm. (4) The gross tumor volumes (GTVs) and the ensuing treatment regimens were changed for 31.3% (5/16) of patients based on the CHO-PET high-affinity uptake and metabolism, in which the change rate was 80% (4/5), 14.3 % (1/7) and 0% (0/4) for patients with WHO Grade II III, and IV gliomas, respectively.ConclusionOur data demonstrate that difference exists between CHO PET and MRI by which to judge and identify residual tumor for patients with brain gliomas. CHO PET is considered to be a supplementary diagnostic approach for MRI. Biological tumor target volume (BTV) displayed in the CHO PET images is useful in determining or delineating the radiotherapy target volume and making decisions in selecting treatment regimens. Tumor target volume may be defined more accurately and rationally when the CHO PET is combined with MRI.     

致痫性神经上皮肿瘤的磁共振成像及临床病理对照

目的：分析致痫性神经上皮脑肿瘤的MRI、PET及临床病理资料,提高对该类肿瘤的诊断水平。方法：本组共31例,病理诊断胚胎发育不良性神经上皮肿瘤（DNT）13例,节细胞胶质瘤或节细胞瘤（GG）7例,复合性胶质神经元肿瘤2例,中枢神经细胞瘤1例,星形胶质细胞瘤8例。临床均以癫痫为首发症状。患者术前均行脑部磁共振检查,9例行PET或CT检查。影像分析病灶部位、大小、形态、信号（密度）特点和病灶周围水肿、占位效应及增强后表现。结果：病灶多位于颞叶和额叶皮质或皮质下,发病年龄以青年为主,病灶多呈圆形或类圆形。DNT以假囊状或小泡状长T2信号,无强化或点状、小结节状强化为特点,4例18F-FDG-PET检查均为低代谢。节细胞瘤或节细胞胶质瘤表现为囊实性、囊性或实性,病灶内钙化占62.5%,无灶周水肿或轻度灶周水肿,增强扫描后呈结节、斑块状不均匀强化。2例18F-FDG-PET显示病灶内有结节状高代谢,2例呈低代谢。结论：致痫性肿瘤多以神经元和混合性胶质神经元肿瘤和低级别胶质星形细胞瘤为多见,MRI有助于上述肿瘤的诊断和鉴别诊断。     

18F-FDOPA PET/MRI fusion in patients with primary/recurrent gliomas: initial experience

Background and purpose

¹⁸F-FDOPA PET demonstrates higher sensitivity and specificity for gliomas than traditional [¹⁸F] FDG PET imaging. However, PET provides limited anatomic localization. The purpose of this study was to determine whether ¹⁸F-FDOPA PET/MRI fusion can provide precise anatomic localization of abnormal tracer uptake and how this activity corresponds to MR signal abnormality.

Methods

Two groups of patients were analyzed. Group I consisted of 21 patients who underwent ¹⁸F-FDOPA PET and MRI followed by craniotomy for tumor resection. Group II consisted of 70 patients with a pathological diagnosis of glioma that had ¹⁸F-FDOPA PET and MRI but lacked additional pathologic follow-up. Fused ¹⁸F-FDOPA PET and MRI images were analyzed for concordance and correlated with histopathologic data.

Results

Fusion technology facilitated precise anatomical localization of ¹⁸F-FDOPA activity. In group I, all 21 cases showed pathology-confirmed tumor. Of these, ¹⁸F-FDOPA scans were positive in 9/10 (90%) previously unresected tumors, and 11/11 (100%) of recurrent tumors. Of the 70 patients in group II, concordance between MRI and ¹⁸F-FDOPA was found in 49/54 (90.1%) of patients with sufficient follow-up; in the remaining 16 patients concordance could not be determined due to lack of follow-up. ¹⁸F-FDOPA labeling was comparable in both high- and low-grade gliomas and identified both enhancing and non-enhancing tumor equally well. In some cases, ¹⁸F-FDOPA activity preceded tumor detection on MRI.

Conclusion

¹⁸F-FDOPA PET/MRI fusion provides precise anatomic localization of tracer uptake and labels enhancing and non-enhancing tumor well. In a small minority of cases, ¹⁸F-FDOPA activity may identify tumor not visible on MRI.     

(68Ga)-EDTA positron emission tomography in the diagnosis of brain tumors

Summary Fifty-two patients with active brain tumors and 8 patients with brain lesions from surgical treatment and/or radio-and/or chemotherapy of their brain tumors were examined by positron emission tomography (PET) using (⁶⁸Ga)-EDTA in addition to conventional X-ray computed tomography (XCT). All patients with active brain tumors showed abnormal uptake of radioactivity in the tumor region, while all treated patients had normal PET scans. Site and shape of abnormal radioactivity accumulation were in good agreement with the tumor as demonstrated by XCT. Small tumors had a tendency to appear larger in PET than in XCT, while tumors with a mean largest diameter of more than 50.7 mm in XCT usually appeared smaller in PET. Despite considerable overlap to tumor classes with respect to their degree of tracer uptake a highly significant decreasing order of tumor-sagittal sinus ratios of radioactivity (TSR) was found, malignant gliomas ranking highest (median TSR 0.634), followed by meningiomas (median TSR 0.522) and metastases (median TSR 0.391), benign gliomas showing the least uptake (median TSR 0.307). These findings suggest that PET with (⁶⁸Ga)-EDTA has a high sensitivity supplementing XCT in the diagnosis of brain tumors, and may be helpful in early detection of recurrent tumor growth after therapy.     

Imaging of gliomas with Cis-4-[18F]fluoro-L-proline

Tumor imaging with cis-4-[18F]fluoro-L-proline (cis-FPro) was compared to that of L-[3H]proline and L-[3H]methionine in F98 rat gliomas by dual-tracer autoradiography. All tracers exhibited high accumulation in the tumors but in the normal brain significant uptake was observed for L-[3H]methionine only. Tumor extent on autoradiograms with L-[3H]proline and L-[3H]methionine was identical to that of histological staining while autoradiograms of cis-FPro showed diffuse uptake in the penumbra of some tumors. First PET studies in 7 patients with cerebral gliomas demonstrated accumulation of cis-FPro in tumor areas with enhancement of Gd-DTPA on MR scans. Uptake of cis-FPro in normal brain tissue was negligible. In one patient with a glioblastoma accumulation of cis-FPro was also found in two brain areas without enhancement of Gd-DTPA on MR scans. Control of MRI suggested tumor growth in these areas at further follow up. Our results indicate that in most gliomas increased cis-FPro uptake is restricted to areas with disruption of the BBB which limits its clinical utility.     

Spatial heterogeneity of low-grade gliomas at the capillary level: a PET study on tumor blood flow and amino acid uptake.

Many low-grade gliomas (World Health Organization grade II) respond to chemotherapy. Cerebral blood flow (CBF) and microvessel density may be critical for drug delivery. We used PET with (18)F-fluoro-ethyl-l-tyrosine (FET) to measure the spatial distribution of the amino acid carrier, which is located at the brain capillaries, and (15)O-H(2)O to measure tumor CBF. METHODS: Seventeen patients with low-grade glioma were studied. Region-of-interest (ROI) analysis was used to quantify tumor tracer uptake, which was normalized to cerebellar uptake (tumor-to-cerebellum ratio). "Active" tumor was defined as tumor having a radioactivity concentration that was at least 110% of the cerebellar activity. This threshold provided measures of active tumor volume, global and peak tumor CBF, and (18)F-FET uptake. Trace ROIs were applied to create voxelwise profiles of CBF and (18)F-FET uptake across tumor and brain. Standard MRI sequences were used for spatial correlations. RESULTS: Fourteen of 17 tumors showed increased global CBF and (18)F-FET uptake. Active tumor volumes ranged between 3 and 270 cm(3) for (18)F-FET and between 1 and 41 cm(3) for CBF. Global (18)F-FET uptake in tumors corresponded to CBF increases (Spearman rank rho = 0.771, P < 0.01). The volumes of increased CBF and (18)F-FET uptake spatially coincided and were also correlated (rho = 0.944, P < 0.01). Trace ROIs showed that irrespective of increased (18)F-FET uptake at the tumor periphery, CBF increases were more confined to the tumor center. Within individual tumors, spatial heterogeneity was present. Particular tumors infiltrating the corpus callosum showed low CBF and (18)F-FET uptake in this tumor region. The patterns observed with PET were not reflected on MRI of the tumors, all of which presented as homogeneous non-gadolinium-enhancing lesions. CONCLUSION: Low-grade gliomas are heterogeneous tumors with regard to the distribution of amino acid uptake and CBF. Both are coupled in the tumor center. At the tumor periphery, where tumor infiltration of surrounding brain occurs, CBF may be low irrespective of increased (18)F-FET uptake. An ongoing study is investigating the effect of chemotherapy on these observations.     

Correlation of hypoxic cell fraction and angiogenesis with glucose metabolic rate in gliomas using 18F-fluoromisonidazole, 18F-FDG PET, and immunohistochemical studies.

PET offers a noninvasive means to assess neoplasms, in view of its sensitivity and accuracy in staging tumors and potentially in monitoring treatment response. The aim of this study was to evaluate newly diagnosed primary brain tumors for the presence of hypoxia, as indicated by the uptake of 18F-fluoromisonidazole (18F-FMISO) and to examine the relationship of hypoxia to the uptake of 18F-FDG and molecular markers of hypoxia. METHODS: Seventeen patients with suspected primary glioma were enrolled prospectively in this study. Sixteen patients had histology, with 2 having metastatic disease. All patients had PET studies with 18F-FMISO and 18F-FDG and MRI studies. Immunohistochemistry was undertaken with tumor markers of angiogenesis and hypoxia. Patients were monitored for disease progression and statistical analysis of data was performed. RESULTS: Of the 14 patients with histology, 8 died with a median time of 16 mo (range, 2-30 mo) until death. Of those who died, 7 had positive and 1 had negative 18F-FMISO uptake. 18F-FMISO uptake was observed in all high-grade gliomas but not in low-grade gliomas. A significant relationship was found between 18F-FDG or 18F-FMISO uptake and expression of VEGF-R1 and Ki67 expression. Other immunohistochemical markers demonstrated a trend toward increased uptake but none was significant. CONCLUSION: 18F-FMISO PET provides a noninvasive assessment of hypoxia in glioma and was prognostic for treatment outcomes in the majority of patients. 18F-FMISO PET may have a role not only in directing patients toward targeted hypoxic therapies but also in monitoring response to such therapies.