PET/MRI融合显像在脑胶质瘤诊断和治疗中的研究进展

脑胶质瘤发病率较高,是颅内最常见的原发肿瘤。MRI技术在脑胶质瘤分级、手术定位和术后放疗靶区勾画中有着重要的作用。但是,越来越多的研究发现,MRI在肿瘤显像方面仍存在局限性,如准确确定肿瘤边界。PET利用组织代谢原理进行功能显像,有利于发现增殖活跃的肿瘤组织。PET与MRI图像的融合,实现了解剖与功能共同显像,为提高脑胶质瘤诊断的准确性提供了一条新途径。     

PET-CT在脑胶质瘤放射治疗靶区确定中的应用

脑胶质瘤放射治疗靶区的确定是一个值得研究的课题。现代放射治疗技术快速发展．从物理调强发展到生物调强，照射靶区的确定更为重要。本文阐述了PET-CT在脑胶质瘤放射治疗几何靶区和生物靶区确定中的意义和作用，以及不同示踪剂对靶区显示的不同贡献。     

MRI和PET显像在阿尔茨海默病早期诊断中的应用

阿尔茨海默病（AD）是一种最常见的进行性神经退行性疾病,严重威胁患者的生命和健康,早期诊断和干预可以减缓甚至逆转该疾病的病情进展。目前,MRI和PET显像已被应用于AD的诊断,其在AD的早期诊断方面均有独特的优势。笔者重点介绍了结构性MRI、功能性MRI和PET显像在AD早期诊断中的应用。     

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。     

18F-FET PET显像在脑胶质瘤中的研究进展

氨基酸类PET在胶质瘤影像检查中应用广泛,尤其是 18F-酪氨酸( 18F-FET)PET显像在脑胶质瘤的诊疗工作中起着重要作用。该文主要综述近年来有关 18F-FET PET显像在脑胶质瘤诊断及鉴别诊断、指导治疗、评估疗效及预后预测等方面的应用现状。     

PET在重体瘤诊断中的应用

PET在垂体瘤的研究中可以观察到垂体的各种生理、生化过程，包括血流量、血容量、局部葡萄糖代谢、氨基酸代谢，蛋白质合成、受体的密度和分布情况等，研究时根据所用正电子显像剂的不同，可以进行不同的临床研究。通过垂体瘤PET的研究，说明PET对垂体瘤的诊断，治疗监测和预后的判断等有很好的应用前景。     

PET-CT在脑胶质瘤放射治疗靶区确定中的应用

脑胶质瘤放射治疗靶区的确定是一个值得研究的课题。现代放射治疗技术快速发展,从物理调强发展到生物调强,照射靶区的确定更为重要。本文阐述了PET-CT在脑胶质瘤放射治疗几何靶区和生物靶区确定中的意义和作用,以及不同示踪剂对靶区显示的不同贡献。     

^(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显像剂18F-FLT在脑胶质瘤中的研究进展

脑胶质瘤是最常见的颅内肿瘤,占脑肿瘤的40%~55%,其诊断时间直接影响患者的预后。近年来,PET显像剂在脑胶质瘤中的应用得到了快速发展。18F-脱氧胸腺嘧啶核苷（18F-FLT）就是其中之一。18F-FLT是经过放射性核素标记的胸腺嘧啶的类似物,是较常见的正电子显像剂,用于评估细胞的增殖情况,它能在肿瘤治疗前、治疗中及治疗后提供其他影像学检查和显像剂不能提供的信息。笔者主要对目前脑胶质瘤显像剂的研究现状,18F-FLT的显像机制、18F-FLT对脑胶质瘤的诊断、分级、鉴别复发与坏死、疗效评估和预后判断以及18F-FLT与Ki-67的关系等方面进行了阐述。     

MRI与PET对癫痫病的诊断价值

癫痫是常见病，以颞叶癫痫最常见，药物难治性癫痫的术前准确定侧和定位是手术成功的关键。MRI对部分癫痫有很重要的诊断价值，特别是结合脑电图和功能性磁共振成像。但是对于MRI诊断阴性的癫痫病人，PET整体定位系统能解决其定位诊断问题。     

PET/CT在指导直肠癌术后放疗中的意义

 目的回顾性探讨PET/CT在检测直肠癌术后患者的分期,分析PET/CT对直肠癌术后骶前软组织肿块的诊断准确率,以及对放射治疗的指导作用.方法选择手术后直肠癌29例,在行放射治疗前行PET/CT检查,其结果分别与同期的CT结果相比较.结果29例中发现7例11处高代谢灶,骶骨前间隙3例,髂骨+腰椎1例,盆腔淋巴结+肝脏2例,腹膜后淋巴结+锁骨上淋巴结1例.结论PET/CT能够更准确地反映手术后直肠癌患者的病变范围,能够指导治疗方案的选择.     

颅内生殖细胞瘤放疗的研究进展

近几十年以来,颅内生殖细胞瘤的放疗方案基本都是基于全脑全脊髓或全脑室放疗,因此,患者具有较高的生存率。近年来对于放疗的研究主要集中于在保证疗效的情况下,尝试减少照射体积或强度,以求进一步减少放疗所带来的并发症。笔者回顾性总结了部分国内外学者在颅内生殖细胞瘤放疗方案的选择上所做的积极的探索与研究,以期为今后的临床工作提供一些思路与参考。     

^18F-FDG PET／CT在鼻咽癌临床分期和疗效监测中的应用

目的探讨^18F-FDGPET／CT显像在鼻咽癌首次分期、再分期及疗效监测中的临床应用价值。方法通过分析86例鼻咽癌患者^18F-FDGPET／CT扫描结果,结合其他临床资料和随访结果,计算^18F-FDGPET／CT显像的准确性、特异性、灵敏度、阳性预测值与阴性预测值,并与CT、MRI进行比较。结果^18F-FDGPET／CT与CT、MRI诊断鼻咽癌的准确率、敏感性、特异性、阳性预测值与阴性预测值的差异均有统计学意义（P〈0．05）。依据^18F-FDGPET／CT结果,改变了4例首次分期、14例再分期的临床诊断和22例患者的治疗方案。结论与CT、MRI相比,^18F-FDGPET／CT显像对鼻咽癌的临床分期及疗效监测具有更重要价值。     

PET/CT对肿瘤放疗策略的影响

目的：探讨PET／CT对肿瘤放疗策略的影响。方法：对189例恶性肿瘤进行放疗前^18F-FDG全身PET／CT检查,应用标准摄取值（SUV）进行评价,病灶区SUV≥2．5为阳性。结果：PET／CT检查后,56例放射策略发生变化,其中14例（25．0％）改行其他治疗,12例（21．4％）将根治性放疗改为姑息性放疗,18例（32．1％）改变了照射靶区,12例（21．4％）调整了放疗剂量。结论：PET／CT为恶性肿瘤放疗前的全面评估和决策提供了更多更有效的临床信息,其功能显影和解剖影像同机融合的突出优势,明显提高了治疗效果,减少或减轻了并发症的发生。     

PET/MRI of the breast

The future clinical use of the combination of positron emission tomography (PET) with 2-Fluoro[F-18]-2-Deoxy-d-Glucose (FDG)and MRI is still unclear. If a patient requires a PET and breast DCE-MRI for staging purposes, both scans can be done in the same visit. In the breast, DCE-MRI is better at lesion detection (sensitivity), margin evaluation, and has a higher specificity than CT. The potential for multiparametric qualitative and quantitative imaging is also an advantage of PET/MRI which provides opportunity to improve tumor characterization and may ultimately lead to outcome prediction. This review discusses technical and clinical aspects of this emerging technology in breast cancer patients.     

16例颅内胶质瘤术后并放射治疗后的18F-FDG PET显像

目的　探讨18F 脱氧葡萄糖 (FDG)PET在颅内胶质瘤术后并放射治疗后随诊中的临床价值。方法　对 16例颅内胶质瘤术后并放射治疗后的患者同期行18F FDGPET和CT、MRI检查 ,采用双盲法对结果进行比较。结果　 16例中 87 5 % (14例 )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、残存肿瘤或肿瘤复发的诊断 ;其中 9例残存肿瘤或肿瘤复发病灶18F FDGPET影像表现为葡萄糖代谢明显增高 ,有 5例得到手术病理证实 ;另 5例术后放射治疗后脑损伤患者和 2例术后软化灶18F FDGPET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　18F FDGPET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 ,结合CT和MRI更能提供病变解剖结构和功能改变的综合信息。     

Comparison of imaging with FDG PET/CT with other imaging modalities in myeloma

Objective To determine the usefulness of FDG PET/CT scanning in the management and staging of myeloma and to assess its strengths and limitations.Design FDG PET/CT scans and all other available imaging studies were reviewed retrospectively from 16 consecutive patients by two experienced musculoskeletal radiologists and two nuclear medicine physicians working in consensus.Patients The 16 patients had undergone a total of 19 FDG PET/CT scans. Radiographs were available in all cases, including 13 skeletal surveys; 25 CT scans (16 chest, three abdominal, four pelvic, one spine, one neck) and 22 MR imaging studies (17 spine, three pelvic, two extremity) also were reviewed. Patients’ records were examined for relevant clinical information. All focal areas of abnormal FDG uptake were correlated with the other imaging studies to determine clinical significance. FDG PET/CT scans also were reviewed to see if small lesions shown on the other imaging studies could be identified in retrospect.Results The 12 men and four women had an average age of 58 years (range 30–69 years). All 16 patients had an established diagnosis of multiple myeloma, with average duration of disease, from time of initial diagnosis to review, of 30 months (range 6 months to 11+ years). The FDG PET/CT scans revealed a total of 104 sites (90 in bone, 14 soft tissue) that were suspicious for neoplastic activity based on a standardized uptake value (SUV) greater than 2.5. Fifty-seven of these sites (55%) were new or previously undetected. The other imaging studies (X-ray, CT, MR) and clinical information confirmed the other 47 areas but also revealed 133 other small skeletal lesions. Six of these 133 additional lesions showed mild FDG uptake on re-review of the PET/CT scans. The FDG PET/CT findings led to management changes in 9/16 patients. MR imaging revealed five cases of diffuse bone involvement (four spine, one scapula) that were not evident by FDG PET/CT.Conclusion FDG PET/CT scans are useful for the management and staging of myeloma. However, if PET/CT were the sole imaging study done, it would miss many additional small lytic skeletal lesions and could miss diffuse spine involvement.     

Where there is no PET/CT

Technology assessment should touch upon four areas; utility, target population, cost and alternatives. Hybrid Positron Emission Tomography/Computed Tomography (PET/CT) is a promising modality for oncologic imaging. However, reservations about its accessibility and affordability prevail. Magnetic Resonance Imaging (MRI) is an alternative with certain key advantages that can potentially prove equivalent if not better than PET/CT. We have highlighted the value of comparative studies between PET/CT and whole body MRI. Diffusion Weighted sequences may aid in better diagnosis of malignancies on MRI. The ‘Eye of Medicine’ should not have a restricted vision even where there is no PET/CT.     

Depiction and characterization of liver lesions in whole body [F]-FDG PET/MRI

Objectives

To assess the value of PET/MRI with [¹⁸F]-FDG using a whole body protocol for the depiction and characterization of liver lesions in comparison to PET/CT.

Methods

70 patients (31 women, 39 men) with solid tumors underwent [¹⁸F]-FDG PET/CT and followed by an additional PET/MRI using an integrated scanner. Two readers rated the datasets (PET/CT; PET/MRI) regarding conspicuity of hepatic lesions (4-point ordinal scale) and diagnostic confidence (5-point ordinal scale). Median scores for lesion conspicuity and diagnostic confidence were compared using Wilcoxon's rank sum test. Prior examinations, histopathology and clinical follow-up (116 ± 54 days) served as standard of reference.

Results

36 of 70 (51%) patients showed liver lesions. Using PET/CT and PET/MRI all patients with liver metastases could correctly be identified. A total of 97 lesions were found (malignant n = 26; benign n = 71). For lesion conspicuity significantly higher scores were obtained for PET/MRI in comparison to PET/CT (p < 0.001). Significantly better performance for diagnostic confidence was observed in PET/MRI, both for malignant as for benign lesions (p < 0.001).

Conclusions

PET/MRI, even in the setting of a whole body approach, provides higher lesion conspicuity and diagnostic confidence compared to PET/CT and may therefore evolve as an attractive alternative in oncologic imaging.     

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。