阿尔茨海默病的神经影像学诊断进展

阿尔茨海默病是一种神经系统退行性疾病,其高发病率和较差预后为老龄化社会带来很大的负担。由于早期临床干预可以改善其预后,故早期诊断就显得尤为重要,就该病早期诊断的神经影像学进展予以综述。     

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。     

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在阿尔茨海默病中的应用和进展

阿尔茨海默病（AD）是老年痴呆的主要类型,约占痴呆病例的60%~80%。随着我国人口平均寿命的延长和老年人口数量的增加,AD的发病率不断提高,给社会及家庭带来巨大的经济负担,引起了国内外学者的高度重视。PET是一种先进的临床影像检查技术,在AD的诊断和研究中具有更高的灵敏度和准确率。笔者就近年来PET在AD中的应用和进展进行综述。     

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。     

乳腺癌的影像学诊断进展

早期诊断和早期治疗是降低乳腺癌死亡率的关键.介绍了目前诊断乳腺癌的各种影像检查方法,分析了不同方法的优势及局限性,评价了其临床应用价值及现状.     

乳腺癌的影像学诊断进展

早期诊断和早期治疗是降低乳腺癌死亡率的关键。介绍了目前诊断乳腺癌的各种影像检查方法，分析了不同方法的优势及局限性，评价了其临床应用价值及现状。     

PET分子探针在阿尔茨海默病早期诊断中的研究进展

阿尔茨海默病(AD)是最常见的痴呆类型,并随着人口老龄化将会变得越来越普遍.在AD 出现临床症状前数十年脑内就可发生病理改变,临床诊断标准不能准确诊检轻度AD及无症状AD.AD的早期诊断越来越受到重视,对发生在AD早期的不可逆性神经损伤前的干预治疗尤为重要.神经影像标志物是最有发展前途的诊断早期AD的方法,PET功能性神经影像是一种能够在早期进行AD病理及分子生物学检查的极具灵敏度、特异度、无创性、客观和定量的方法,因此能够诊断出早期的、轻微且无临床症状的老年痴呆症.     

帕金森病的影像学诊断进展

帕金森病(PD)是中老年人最常见的神经退行性疾病之一,是一种以运动迟缓、强直和静止性震颤为主要临床症状的神经变性疾病。2005年,北京、西安和上海3个大城市的流行病学调查发现,PD在65岁以上人群中的发病率为1.7%,已经接近发达国家的发病率[1],发病人数保守估计超过170万。由于PD致残率高,病程长,严重影响了中老年人的生活质量。神经影像及尸检结果显示,在退行性神经病变的早期进行神     

阿尔茨海默病PET正电子药物应用与研究进展

阿尔茨海默病（AD）严重危害人们的身心健康。伴随PET分子成像的发展,出现了一系列针对AD的正电子药物,其中匹兹堡化合物B（PIB）及其衍生物类PET正电子药物研究最为成熟,部分已获准应用于临床,在AD诊断与治疗方面显示出重要价值。随着人们对AD发生机制研究的不断深入,近年又相继出现了包括蛋白类、受体类以及肽类在内的更多种类AD相关PET正电子药物。该文就此类正电子药物的应用与研究进展做一综述。     

Remote metabolic effects of cerebrovascular lesions: magnetic resonance and positron tomography imaging

Summary Combined Positron Emission Tomography (PET) and Proton Magnetic Resonance Imaging (MRI) study were performed in six patients with chronic supratentorial stroke to investigate whether remote hypometabolic regions revealed by PET showed any abnormality on MRI. Either regional oxygen consumption (n=4) or glucose utilization (n=2) were measured using PET and the ¹⁵O steady state ¹⁸FGD technique, respectively. Four patients, with deeply located brain lesions, showed a significant metabolic reduction in the overlying cerebral cortex. In the remaining two patients, affected by a large cortical infarct, there was a significant crossed cerebellar hypometabolism. The MRI weighted by the parameters spin density (), spin lattice (T₁) and spin-spin (T₂) relaxation times were obtained employing various sequences in the same subjects. In no patient did the MRI show any contrast modification in these hypometabolic remote regions, suggesting that subtle loss of tissue and/or biochemical change do not underlie the reduction in metabolic rate.     

椎体淋巴瘤MRI及PET临床应用价值

目的探讨椎体淋巴瘤MRI及正电子发射体层成像(PET)的影像特征及临床应用价值。资料与方法回顾性分析经病理证实的15例椎体淋巴瘤患者的MRI和PET表现,原发性骨淋巴瘤6例,继发性9例。结果MRI:原发性6例均为单一椎体压缩性骨折伴局部硬膜外和/或椎体旁软组织肿块,软组织范围超过病变椎体;继发性9例均为多椎体压缩性改变,7例伴硬膜外和/或椎体旁软组织肿块。椎体病变T1WI呈等或混杂信号,T2WI呈稍高信号。软组织肿块T1WI呈等/低信号,T2WI呈稍高信号,明显均匀强化5例,轻度均匀强化8例。PET:原发性6例均为术后PET检查,1例术后2个月显示局部复发,5例无异常;继发性9例(术前6例、术后3例)PET显示多椎体、淋巴结及脾葡萄糖代谢异常增高。结论椎体原发性淋巴瘤多为单椎体病变;继发性常为多椎体受累,两者均可伴硬膜外和/或椎体旁软组织肿块。椎体淋巴瘤MRI、PET表现无特异性,MRI能清晰显示椎管内病灶与脊髓的关系,PET对鉴别原发性与继发性淋巴瘤有重要价值。     

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。     

MRI and 18F-fluorodeoxyglucose positron emission tomography in hemimegalencephaly

We report hemimegalencephaly in a 44-year-old woman with mental retardation, epilepsy and a mild hemiparesis. In addition to typical findings on MRI, 2-deoxy-2[¹⁸F]fluorodeoxyglucose positron-emission tomography (PET) demonstrated glucose hypometabolism of the affected hemisphere. The results of PET have been coregistered with morphological information from the MRI studies by image fusion. Received: 14 December 1999/Accepted: 15 February 2000     

亨廷顿病的影像学表现

目的 报道亨廷顿病的影像学表现. 资料与方法 分析1例经基因检测证实的亨廷顿病患者CT、MRI、氢质子磁共振波谱(1H-MRS)、正电子发射体层成像(PET/CT)影像学表现,并复习文献. 结果 头颅CT及MRI提示双侧尾状核萎缩,侧脑室前角扩大.尾状核头部最大直径、壳核最大直径值减低、双尾状核比率和双额角比率值增高.1H-MRS出现异常乳酸峰并提示基底节区N-乙酰天门冬氨酸/肌酸值减低,胆碱复合物/肌酸值增高.PET/CT示双侧基底节代谢减低. 结论 1H-MRS代谢异常及PET/CT基底节区代谢减低有助于诊断亨廷顿病.     

Balo's concentric sclerosis followed by MRI and positron emission tomography

We report a case of Balo's concentric sclerosis diagnosed in vivo by characteristic MRI changes and stereotactic biopsy. Follow-up after 6 months of immunosuppressive treatment demonstrated virtually complete clinical remission, reduction of the white matter lesions on MRI and normalisation of regional cerebral glucose metabolism as assessed by positron emission tomography not only in white matter but also in the cerebral grey matter structures with input from the affected regions.     

Whole-body MRI at 1.5 T and 3 T compared with FDG-PET-CT for the detection of tumour recurrence in patients with colorectal cancer

The purpose of this study was to assess the diagnostic accuracy of whole-body MRI (WB-MRI) at 1.5 T or 3 T compared with FDG-PET-CT in the follow-up of patients suffering from colorectal cancer. In a retrospective study, 24 patients with a history of colorectal cancer and suspected tumour recurrence underwent FDG-PET-CT and WB-MRI with the use of parallel imaging (PAT) for follow-up. High resolution coronal T1w-TSE and STIR sequences at four body levels, HASTE imaging of the lungs, contrast-enhanced T1w- and T2w-TSE sequences of the liver, brain, abdomen and pelvis were performed, using WB-MRI at either 1.5 T (n = 14) or 3 T (n = 10). Presence of local recurrent tumour, lymph node involvement and distant metastatic disease was confirmed using radiological follow-up within at least 5 months as a standard of reference. Seventy seven malignant foci in 17 of 24 patients (71%) were detected with both WB-MRI and PET-CT. Both investigations concordantly revealed two local recurrent tumours. PET-CT detected significantly more lymph node metastases (sensitivity 93%, n = 27/29) than WB-MRI (sensitivity 63%, n = 18/29). PET-CT and WB-MRI achieved a similar sensitivity for the detection of organ metastases with 80% and 78%, respectively (37/46 and 36/46). WB-MRI detected brain metastases in one patient. One false-positive local tumour recurrence was indicated by PET-CT. Overall diagnostic accuracy for PET-CT was 91% (sensitivity 86%, specificity 96%) and 83% for WB-MRI (sensitivity 72%, specificity 93%), respectively. Examination time for WB-MRI at 1.5 T and 3 T was 52 min and 43 min, respectively; examination time for PET-CT was 103 min. Initial results suggest that differences in accuracy for local and distant metastases detection using FDG-PET-CT and WB-MRI for integrated screening of tumour recurrence in colorectal cancer depend on the location of the malignant focus. Our results show that nodal disease is better detected using PET-CT, whereas organ disease is depicted equally well by both investigations.     

影像组学在脑胶质瘤中的研究进展

影像组学可以高通量地提取医学影像的特征并进行分析,建立影像与肿瘤异质性、基因表达等信息之间的联系,进而提供更为精准的临床决策。目前脑胶质瘤的影像组学研究基于不同的成像方法,可以提取肿瘤灰度直方图特征、形态特征和表征肿瘤异质性的纹理特征等,主要应用于脑胶质瘤的分级和鉴别、预测基因表达及评估生存期和治疗反应等。就影像组学的流程、基于不同成像的影像组学处理方法以及影像组学方法在脑胶质瘤中的应用进展予以综述。     

Evaluation of Dixon Sequence on Hybrid PET/MR Compared with Contrast-Enhanced PET/CT for PET-Positive Lesions

Purpose

Hybrid positron emission tomography and magnetic resonance (PET/MR) imaging performs a two-point Dixon MR sequence for attenuation correction. However, MR data in hybrid PET/MR should provide anatomic and morphologic information as well as an attenuation map. We evaluated the Dixon sequence of hybrid PET/MR for anatomic correlation of PET-positive lesions compared with contrast-enhanced PET/computed tomography (CT) in patients with oncologic diseases.

Methods

Twelve patients underwent a single injection, dual imaging protocol. PET/CT was performed with an intravenous contrast agent (85 ± 13 min after ¹⁸F-FDG injection of 403 ± 45 MBq) and then (125 ± 19 min after injection) PET/MR was performed. Attenuation correction and anatomic allocation of PET were performed using contrast-enhanced CT for PET/CT and Dixon MR sequence for hybrid PET/MR. The Dixon MR sequence and contrast-enhanced CT were compared for anatomic correlation of PET-positive lesions (scoring scale ranging from 0 to 3 for visual ratings). Additionally, standardized uptake values (SUVs) for the detected lesions were assessed for quantitative comparison.

Results

Both hybrid PET/MR and contrast-enhanced PET/CT identified 55 lesions with increased FDG uptake in ten patients. In total, 28 lymph nodes, 11 bone lesions, 3 dermal nodules, 3 pleural thickening lesions, 2 thyroid nodules, 1 pancreas, 1 liver, 1 ovary, 1 uterus, 1 breast, 1 soft tissue and 2 lung lesions were present. The best performance was observed for anatomic correlation of PET findings by the contrast-enhanced CT scans (contrast-enhanced CT, 2.64 ± 0.70; in-phase, 1.29 ± 1.01; opposed-phase, 1.29 ± 1.15; water-weighted, 1.71 ± 1.07; fat weighted, 0.56 ± 1.03). A significant difference was observed between the scores obtained from the contrast-enhanced CT and all four coregistered Dixon MR images. Quantitative evaluation revealed a high correlation between the SUVs measured with hybrid PET/MR (SUVmean, 2.63 ± 1.62; SUVmax, 4.30 ± 2.88) and contrast-enhanced PET/CT (SUVmean, 3.88 ± 2.30; SUVmax, 6.53 ± 4.04) in PET-positive lesions (SUVmean, ρ = 0.93; SUVmax, ρ = 0.95), although hybrid PET/MR presented a decrease of SUVs compared with contrast-enhanced PET/CT (mean reduction; SUVmean, 32.44 ± 15.64 %; SUVmax, 35.16 ± 12.59 %).

Conclusions

Despite different attenuation correction approaches, the SUV of PET-positive lesions correlated well between hybrid PET/MR and contrast-enhanced PET/CT. However Dixon MR images acquired for attenuation correction were insufficient to provide anatomic information of PET images because of low spatial resolution. Thus, additional MR sequence with fast and higher resolution may be necessary for anatomic information.