PET/MRI改善癌症患儿管理

一体化PET/MRI通过一站式成像提供肿瘤解剖学及功能评估, 且与18F-FDG PET/CT相比其辐射暴露量减少80%, 因此对癌症患儿的分期与再分期具有显著临床价值。该文回顾了18F-FDG PET/MRI在小儿肿瘤中的临床应用, 尤其关注PET/MRI在患儿管理中的价值。来自4个不同机构的PET/MRI应用先行者分享了他们对PET/MRI技术在癌症患儿评估中特殊优势的见解。文章作者讨论了全身PET/MRI在评估某些解剖区域(如软组织和骨髓)中的价值以及儿童特殊的PET/MRI影像学特征, 并强调了全身PET/MRI如何通过在不失去诊断准确性的同时减少所需放射学检查次数(因此减少辐射暴露), 改善淋巴瘤、肉瘤和神经纤维瘤病患儿的临床管理。文章论述了PET/MRI如何帮助区分恶性肿瘤与感染性或炎性疾病;另外, 简要探讨了PET/MRI用于接受免疫治疗的患儿疗效评估以及对不同诊疗一体化药物评估的未来研究方向。从儿童应用中所获得的经验也可拓展至成人患者的评估中。     

原发性骨肌肿瘤的PET/CT应用进展

PET/CT的融合成像对众多实性肿瘤的分期及治疗有重要价值。然而,该技术对骨肌恶性肿瘤的评估尚未实现常规临床应用。采用MR和CT的体层成像技术进行评估     

PET/MRI在肿瘤研究中的新进展

PET/MRI成像整合了PET提供的人体生理代谢、分子信息和MRI提供的功能、解剖形态信息,在肿瘤诊断、评估肿瘤生物学行为(包括分期、分级、浸润深度、远处转移)、评价治疗疗效及预后方面具有较高的准确性、敏感性、特异性,实现了PET及MR成像设备的优势互补。就PET/MRI在肿瘤中的应用现状及其发展前景进行回顾和展望。     

PET/MRI在胰腺肿瘤中的应用

PET/MRI是一种将PET和MRI融合的新型影像诊断技术,其整合了PET提供的人体生理代谢、分子信息和MRI提供的功能及解剖形态信息。相较于CT,MRI具有更高的软组织对比度,可多参数成像,且无辐射。PET/MRI在胰腺癌病灶检测、术前分期和预后评估方面优于PET/CT。~(68)Ga标记的生长抑素受体显像剂PET/MRI能够提高胰腺神经内分泌肿瘤的检测和诊断能力。新型显像剂的研发和应用能够提高胰腺肿瘤PET/MRI的特异性和精准性。就PET/MRI在胰腺癌的诊断、分期及疗效监测的应用价值及其对胰腺神经内分泌肿瘤的研究进展予以综述。     

非小细胞肺癌术前淋巴结分期采用联合MRI和PET/CT解释标准的建议

摘要目的联合利用MRI及PET/CT为非小细胞肺癌术前淋巴结分期确定阳性的恶性淋巴结判读标准。方法49例经活检证实的非小细胞肺癌病人,同时接受PET/CT及胸部MRI(DWI)检查。在MRI联合PET/CT解释时应用纳入法(任一项判断为阳性即为阳性)及排除法(两者均为阳性者)评估每个淋巴结部位是否存在转移。淋巴结分期由病理证实。以结节分区及病人为分析单位评价MRI联合PET/CT诊断的准确性,并与单独利用PET/CT诊断的准确性比较。     

PET/CT和PET/MR在黑色素瘤中的临床应用及新进展

黑色素瘤易转移、复发率高,已经成为严重危及人民健康的恶性肿瘤之一,早期诊断和准确分期对预后及远期生存十分关键。18F-FDG PET/CT作为一项集PET与CT于一体的成像模式,被广泛地应用于包括黑色素瘤等在内的恶性肿瘤的诊断、分期及疗效的评估。随着一体化PET/MR成像系统研发的成功,多模态成像技术向前迈进了一大步,实现了真正意义上的数据同步采集。笔者就18F-FDG PET/CT及PET/MR在黑色素瘤分期、复发和疗效评价中的研究现状进行综述,介绍了多模态成像技术在黑色素瘤中的新进展。     

18F-FDG PET/MR在鼻咽癌分期中的价值研究及半定量分析

目的 探讨¹⁸F-FDG PET/MR在鼻咽癌分期中的价值及半定量分析。方法 回顾性分析78例鼻咽癌患者相关资料，根据PET/MR显像结果按照AJCC第8版TNM分期标准，比较与其临床实际分期的准确性。采用两独立样本t检验和Mann-Whitney U检验分析数据，采用Kappa一致性检验评估PET/MR影像分期与临床实际分期的诊断一致性，行受试者工作特征(ROC)曲线分析计算各参数对T分期中的诊断效能。结果 PET/MR在治疗前患者T分期、N分期、M分期及总体分期的准确性分别为：98.72%、93.59%、100%、94.87%,PET/MR分期与临床分期诊断一致性较高(Kappa值=0.926)。半定量参数分析SUV_max、SUV_mean、SUV_max/ADC_min与T分期有相关性(P=0.003、0.005、0.004,P<0.01);淋巴结的SUV_max与N分期有明显相关性(P=0.000,P<0.01),ROC曲线分析显示SUV     

18F-FDG PET/CT与18F-FDG PET/MRI在卵巢癌临床应用中的进展

卵巢癌是妇科恶性肿瘤中病死率最高的肿瘤。18F-FDG PET/CT在卵巢癌的诊断、分期、疗效及预后的评估上优于常规影像技术,可以指导临床采取有针对性的治疗方案,以获得更好的治疗效果。PET/MRI是最近几年继PET/CT后投入临床应用的另外一种多模态影像技术,因其多序列成像、软组织分辨率较高和辐射剂量较低,对卵巢癌的诊治具有独特的优势。笔者对18F-FDG PET/CT和18F-FDG PET/MRI在卵巢癌中的临床应用进行综述。     

PET/MRI在肺癌中的潜在临床应用价值

PET/MRI作为新出现的融合影像技术,其临床应用价值尚未得到充分证实。与CT相比,MRI具有软组织对比分辨力高、无辐射、多参数成像、能够提供更多功能信息的优势,PET与MRI的融合对于肺癌的潜在应用价值可能要优于PET/CT。简述不同的PET/MRI系统的设计,并从肺结节的检出、鉴别诊断、TNM分期、预后/早期疗效评价/肿瘤复发4个方面介绍PET/MRI在肺癌中的潜在临床价值。     

18F-FDG PET/MRI在胰腺癌中的临床应用及新进展

胰腺癌是一种恶性程度高、易转移、进展快、预后差的恶性肿瘤,早期诊断、准确分期和及时的疗效评估对胰腺癌患者至关重要。一体化的PET/MRI作为一种新型的多模态成像技术,集合了MRI对软组织分辨率高、多序列、多参数和PET代谢显像的高灵敏度等优势,在胰腺癌患者的肿瘤分期、疗效评估、预后预测、复发监测等方面具有潜在的应用价值。因此,笔者就18F-氟脱氧葡萄糖（FDG）PET/MRI的优势及其在胰腺癌中的临床应用及新进展进行综述。     

PET and PET/CT in pediatric oncology

18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and FDG-PET/computed tomography (CT) are becoming increasingly important imaging tools in the noninvasive evaluation and monitoring of children with known or suspected malignant diseases. In this review, we discuss the preparation of children undergoing PET studies and review radiation dosimetry and its implications for family and caregivers. We review the normal distribution of 18F-fluorodeoxyglucose (FDG) in children, common variations of the normal distribution, and various artifacts that may arise. We show that most tumors in children accumulate and retain FDG, allowing high-quality images of their distribution and pathophysiology. We explore the use of FDG-PET in the study of children with the more common malignancies, such as brain neoplasms and lymphomas, and the less-common tumors, including neuroblastomas, bone and soft-tissue sarcomas, Wilms' tumors, and hepatoblastomas. For comparison, other PET tracers are included because they have been applied in pediatric oncology. Multiple multicenter trials are underway that use FDG-PET in the management of children with neoplastic disease; these studies should give us greater insight into the impact FDG-PET can make in their care. PET is emerging as an important diagnostic imaging tool in the evaluation of pediatric cancers. The recent advent of dual-modality PET-computed tomography (PET/CT) imaging systems has added unprecedented diagnostic capability by revealing the precise anatomical localization of metabolic information and metabolic characterization of normal and abnormal structures. The use of CT transmission scanning for attenuation correction has shortened the total acquisition time, which is an especially desirable attribute in pediatric imaging. Moreover, expansion of the regional distribution of the most common PET radiotracer, FDG, and the introduction of mobile PET units have greatly increased access to this powerful diagnostic imaging technology. Here, we review the clinical applications of PET and PET/CT in pediatric oncology. General considerations in patient preparation and radiation dosimetry will be discussed.     

A look ahead: PET/MR versus PET/CT

Introduction  

Integration of positron emission tomography (PET) and magnetic resonance (MR) has become a topic of increasing interest to the imaging community over the past two years.     

PET and PET/CT in endocrine tumours

Functional information provided by PET tracers together with the superior image quality and the better data quantification by PET technology had a changing effect on the significance of nuclear medicine in medical issues. Recently introduced hybrid PET/CT systems together with the introduction of novel PET radiopharmaceuticals have contributed to the fact that nuclear medicine has become a growing diagnostic impact on endocrinology. In this review imaging strategies, different radiopharmaceuticals including the basic mechanism of their cell uptake, and the diagnostic value of PET and PET/CT in endocrine tumours except differentiated thyroid carcinomas will be discussed.     

PET/CT Fluoroscopy during PET/CT-Guided Interventions: Initial Experience

This study assessed the feasibility and functionality of the use of a high-speed image fusion technology to generate and display positron emission tomography (PET)/computed tomography (CT) fluoroscopic images during PET/CT-guided tumor ablation procedures. Thirteen patients underwent 14 PET/CT-guided ablations for the treatment of 20 tumors. A Food and Drug Administration–cleared multimodal image fusion platform received images pushed from a scanner, followed by near–real-time, nonrigid image registration. The most recent intraprocedural PET dataset was fused to each single-rotation CT fluoroscopy dataset as it arrived, and the fused images were displayed on an in-room monitor. PET/CT fluoroscopic images were generated and displayed in all procedures and enabled more confident targeting in 3 procedures. The mean lag time from CT fluoroscopic image acquisition to the in-room display of the fused PET/CT fluoroscopic image was 21 seconds ± 8. The registration accuracy was visually satisfactory in 13 of 14 procedures. In conclusion, PET/CT fluoroscopy was feasible and may have the potential to facilitate PET/CT-guided procedures.     

Integrated PET/MR

Integrated whole‐body PET/MR hybrid imaging combines excellent soft tissue contrast and various functional imaging parameters provided by MR with high sensitivity and quantification of radiotracer metabolism provided by positron emission tomography (PET). While clinical evaluation now is under way, integrated PET/MR demands for new technologies and innovative solutions, currently subject to interdisciplinary research. Attenuation correction of human soft tissues and of hardware components has to be MR‐based to maintain quantification of PET imaging because computed tomography (CT) attenuation information is missing. This brings up the question of how to provide bone information with MR imaging. The limited field‐of‐view in MR imaging leads to truncations in body imaging and MR‐based attenuation correction. Another research field is the implementation of motion correction technologies to correct for breathing and cardiac motion in view of the relatively long PET data acquisition times. Initial clinical applications of integrated PET/MR in oncology, neurology, pediatric oncology, and cardiovascular disease are highlighted. The hybrid imaging workflow here has to be tailored to the clinical indication to maximize diagnostic information while minimizing acquisition time. PET/MR introduces new artifacts that need special observation and innovative solutions for correction. Finally, the rising need for appropriate phantoms and standardization efforts in PET/MR hybrid imaging is discussed. J. Magn. Reson. Imaging 2014;39:243–258 . © 2013 Wiley Periodicals, Inc .     

PET/CT artifacts

There are several artifacts encountered in positron emission tomography/computed tomographic (PET/CT) imaging, including attenuation correction (AC) artifacts associated with using CT for AC. Several artifacts can mimic a 2-deoxy-2-[18F] fluoro-d-glucose (FDG) avid malignant lesions and therefore recognition of these artifacts is clinically relevant. Our goal was to identify and characterize these artifacts and also discuss some protocol variables that may affect image quality in PET/CT.