Analysis of pathogenic factors of radiation encephalopathy after radiotherapy for nasopharyngeal carcinoma

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Clinical manifestations of radiation encephalopathy after radiotherapy for nasopharyngeal carcinoma and their comparative ana

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MRI-T2 values in the differentiation of recurrence and fibrosis after radiation of nasopharyngeal carcinoma.

The possibility of T2 values in the differentiation of local recurrence and irradiation fibrosis was studied prospectively in 36 patients with nasopharyngeal carcinoma (NPC) after radiotherapy. All the patients had a soft-tissue mass in the nasopharynx demonstrated by CT. Fourteen patients had tumor recurrence, 20 radiation fibrosis, 1 postradiation edema, and 1 inflammatory change. The control group consisted of 8 patients with untreated NPC. It was found that T2 was longer in patients with tumor than in patients with radiation fibrosis. We conclude that MRI may be used as a noninvasive method for differentiating radiation fibrosis from local recurrent NPC, but the prolonged T2 value of tumor is not specific and may be seen in radiation edema and infection.

     

Magnetic resonance imaging of Alzheimer’s disease: from diagnosis to therapeutic evaluation

Alzheimer＇s disease（AD）is a devastating late-life dementia that produces progressive loss of memory and mental faculties in elderly people.It is important to identify the earliest evidence of AD and to monitor the development of this disease for us to make positive response to its management.Magnetic resonance imaging（MRI）is powerful to image the tissue or organ without damnification.MRI can be employed to diagnose the early AD development and monitor the key biomarker development in AD.MRI may be helpful not only in diagnosing early AD,but also in evaluating its development.This article reviews the progress of MRI on the diagnosis and detection of AD,and makes comments on its therapeutic application.     

Genital carcinoma after radiotherapy for carcinoma of the cervix. Report of two cases.

Two cases of genital carcinoma were found after radiotherapy for carcinoma of the cervix. Vulval carcinoma occurred 30 years after radiation with initial symptoms of itching and whitish changes of the skin at the external genitalia. Adenocarcinoma of the endometrium occurred 9 years after radiation and diffused intra-abdominal metastasis was found surgically. The sites of second malignancies following irradiation for cervical carcinoma and the time interval between them were reviewed. The characteristics of the post-radiation vulval carcinoma and the endometrial carcinoma were discussed.

     

Preliminary evaluation of magnetic resonance fresh blood imaging for diagnosis of Budd-Chiari syndrome

Background Budd-Chiari syndrome （BCS） is a rare disease with portal hypertension caused by the blockage of the hepatic vein and/or the inferior vena cava （IVC）. Angiography is the ＂golden standard＂ for diagnosis, but it is an invasive examination. To assess the diagnostic value of a fresh blood imaging （FBI） relative to BCS, we used a magnetic resonance angiography （MRA） with an FBI sequence for a preoperative evaluation of the BCS patients in this study. Methods Fifty patients who were suspected of having BCS after they had been checked by a B-ultrasound were studied. 2D and 3D FBI were performed on a 1.5T superconductive MR scanner. Original images were rebuilt using a maximal intensity projection （MIP） method on the console. Two doctors reviewed all images before they learned of the angiography results. We then compared the diagnoses obtained from the FBI and angiography results to evaluate the diagnostic value of the FBI. Results Forty-one patients were diagnosed as BCS and 9 as non-BCS based on an angiography. The FBI correctly diagnosed 38 patients, incorrectly diagnosed 1 patient, and missed diagnosis in 3 patients. Thus, the diagnostic sensitivity of the FBI is 93% （38/41）, the specificity is 89% （8/9） and the accuracy is 92% （46/50）. The FBI images of the 13 membranous stenoses of the IVC showed a sudden stenosis of the post-liver segment of the IVC. The Images of the 5 patients with a membranous obstruction of the IVC showed IVC thickening and an absence of blood signals in the post-hepatic segment of the IVC. The images of the 4 patients with the segmental thrombosis of the IVC showed abnormal and intermittent signals in the IVC. The images of the 6 patients with a simple hepatic vein obstruction showed obstructive hepatic veins. The images of the 6 patients with the stenosis of both the IVC and the hepatic veins showed the stenosis of the IVC, the thickening of the hepatic veins and the formation of a compensatory circulation within the liver. Lastly, the images of the 7 patients showed a combination of the IVC thrombosis with stenosis or with the obstruction of one or two hepatic veins. Conclusions An FBI can show a membranous stenosis, and an obstruction and thrombosis of the IVC. In addition, it can also demonstrate the thickening of the flexural hepatic vein and the development of intra-hepatic compensatory branches with slow blood flow. Thus, it can guide the puncturing and opening of the hepatic vein involved in an interventional therapy for BCS patients.     

Magnetic resonance imaging findings in Lhermitte-Duclos disease:reports of three cases

Lghaernmgliitotcey-Dtoumcalos o fdis ethaese c(e rLeDbeDllu)m,, or is dy aspla rsatriechamartomatous lesion characterized by a slowly enlargingmass within the cerebellar cortex·The disease revealsunique appearance on magnetic resonance imaging(MRI)·Recognition of the imaging features makes thecorrect diagnosis possible even without a pathologicalexamination·Three cases are presented and analyzed inthis report·CASE REPORTSCase 1A 32-year-old man visited our clinic complaining ofinte…     

Magnetic resonance imaging in hepatolenticular degeneration. Analysis of 9 cases.

Nine patients with biochemically proved Wilson's disease underwent magnetic resonance imaging (MRI) of the brain. Areas of abnormal signal, long T1 and long T2, caused by gliosis and edema were seen in the lenticula, thalami, caudatum, brain stem as well as in the dentate nuclei. The abnormalities were bilateral and symmetric. Asymmetric focal white matter lesions were noted in a few patients. Focal atrophies were seen in the head of caudatum. Symmetric cavitations were only seen in the lenticular nuclei. Acute progressive type (2 patients) was characterized by cavity formation, and chronic progressive type (7 patients) by gliosis, edema and focal atrophy.

     

Magnetic resonance susceptibility weighted imaging in detecting intracranial calcification and hemorrhage

Background Computed tomography （CT） is better than routine magnetic resonance imaging （MRI） in detecting intracranial calcification. This study aimed to assess the value of MR susceptibility weighted imaging （SWI） in the detection and differentiation of intracranial calcification and hemorrhage.
Methods Enrolled in this study were 35 patients including 13 cases of calcification demonstrated by CT and 22 cases of intracerebral hemorrhage. MR sequences used in all the subjects included axial T1WI, T2WI and SWI. The phase shift （PS） of calcification and hemorrhage on SWI was calculated and their signal features on corrected phase images were compared. The sensitivity of T1WI, T2WI and SWI in detecting intracranial calcification and hemorrhage was analyzed statistically.
Results The detection rate of SWI for cranial calcification was 98.2%, significantly higher than that of T1WI and T2WI. It was not significantly different from that of CT （P 〉0.05）. There were 49 hemorrhagic lesions at different stages detected on SWI, 30 on T2WI and 18 on T1WI. The average PS of calcification and hemorrhage was ＋0.734±0.073 and -0.112±0.032 respectively （P 〈0.05）. The PS of calcification was positive and presented as a high signal or the mixed signal dominated by a high signal on the corrected phase images, whereas the PS of hemorrhage was negative and presented as a low signal or the mixed signal dominated by a low signal.
Conclusions SWI can accurately demonstrate intracranial calcification, not dependant on CT. Being more sensitive than routine MRI in detecting micro-hemorrhage, SWI may play an important role in differentiating cerebral diseases associated with calcification or hemorrhage.     

Magnetic resonance imaging (MRI) in 100 cases of mass lesions in the liver.

This study denotes that MRI is a valid imaging modality in the differential diagnosis of mass lesions in the liver. From the different prolongation of T2 relaxation time, it is possible to differentiate benign and malignant liver masses. Cavernous hemangioma and cyst present high signal intensity on heavily T2 weighted images whereas hepatoma and liver metastasis show moderate signal intensity. Quantitative study, including T2 value calculation and tumor mass/liver ratio, is a complementary measure for the differential diagnosis of liver mass lesions. Active and passive maneuvers to restrict the abdominal respiration for the preparation of patients before MR scanning are simple and effective approaches to reduce the respiratory motion artifacts.

     

鼻咽癌单程与再程放射治疗后放射性脑损伤临床分析

目的探讨鼻咽癌单程与再程放疗后放射性脑损伤(REP)的临床特点。方法回顾性分析2 103例鼻咽癌放疗患者的临床资料,总结单程放疗后REP和再程放疗后REP患者的临床特点。结果鼻咽癌再程放疗患者REP发生率(9.60%)明显高于单程放疗者(2.07%,P<0.05);再程放疗后REP组REP中位潜伏期(2 a)明显短于单程放疗后REP组(5 a,P<0.05);再程放疗后REP组REP患者死亡率(33.3%)明显高于单程放疗后REP组(7.32%,P<0.05)。结论鼻咽癌放疗后REP发生部位与放疗程数无明显相关性,但放疗后REP发病率、中位潜伏期、及患者死亡率与放疗程数有明显相关性。     

鼻咽癌放疗后放射性脑病发生率对比分析

采用两种放疗方案对NPC进行治疗，并比较其REP的发生率。REP的发生率采用新法的A组为6．4％，传统法的B组为18．7％，两组结果有显著性差异（P＜0．05）。预防REP发生的主要措施为：按照“小而不漏”的原则设野，严格控制放疗总量及分割次数。     

鼻咽癌调强适形放疗前后动态增强特征的研究

目的探讨鼻咽癌调强适形放疗前后MRI动态增强灌注成像的时间-信号变化特征。方法选择初诊未治疗鼻咽癌患者326例,于调强放疗前后行MRI动态增强扫描,分析病灶放疗前后的时间-信号强度变化的曲线特征。结果鼻咽癌放疗前动态增强曲线多呈速升-速降型或速升-平台型,放疗后动态增强曲线多呈缓慢上升型或缓升-平台型。结论调强适形放疗不仅可以缩小鼻咽癌的肿瘤体积,治疗其局部侵犯和淋巴结转移,同时可有效抑制肿瘤的血管生成,降低肿瘤活性。     

PET/CT imaging of delayed radiation encephalopathy following radiotherapy for nasopharyngeal carcinoma

Background With the significant improvement in the survival of patients with nasopharyngeal carcinoma （NPC） undergoing radiotherapy and the growing availability of the sophisticated imaging modalities, the number of radiation encephalopathy （RE） cases relating to NPC radiotherapy is increasing. In this study, we investigated the metabolic and density changes of the compromised brain tissues during delayed RE using a positron-emission tomography-computed tomography （PET/CT） to provide clinical evidences for the diagnosis of delayed RE following radiotherapy for NPC. Methods The PET/CT manifestations and the clinical data of 53 pathologically confirmed NPC patients with delayed RE following radical radiotherapy and 15 healthy volunteers were investigated. The standardized uptake values （SUV） of the bilateral temporal lobes, the occipital lobe and the brain stem were measured respectively; and then the metabolic reduction rate of 88 temporal lobes and 13 brain stems were calculated for a statistical comparison between the two groups. Results The earliest case of delayed RE in the investigated patients occurred 1.5 years after radiotherapy. Delayed RE frequently involved the inferior temporal lobe. For patients with delayed RE confirmed by clinical symptoms and imaging findings, PET maintained a 100% coincidence rate with CT; however, in the 25 temporal lobes of the 35 delayed RE patients, PET revealed obvious hypometabolic changes whereas CT displayed normal density. The incidence of brain stem metabolic reductions was 24.5% （13/53） in the investigated patients, including 4 patients with hypometabolic changes shown by PET and negative finding shown by CT. The incidence of granuloma adjacent to the hypometabolic region in the temporal lobe was 12.5% （11/88）. Conclusion Delayed RE patients exhibit significant hypometabolic changes in the inferior temporal lobe, captured by PET much earlier than by CT. PET/CT offers a valuable means for the diagnosis of delayed RE in subacute stages and granuloma formation.     

鼻咽癌放射性脑病的诊断和治疗

目的分析鼻咽癌放射性脑病（ＲＥＰ）的诊断和治疗方法。材料和方法为２８例鼻咽癌放疗后放射性脑病患者行ＣＴ检查,其中１０例又行ＭＲＩ检查,９例在我院接受治疗。结果和结论（１）ＣＴ对鼻咽癌放射性脑病的诊断有一定价值,但ＭＲＩ对后颅窝和脑干病变的显示优于ＣＴ;（２）放射性脑病可能是放疗致脑组织血管损伤后引起免疫改变的结果：（３）本组９例患者经应用激素、甘露醇、多种维生素等治疗,均取得不同程度的改善。因此．建议对鼻咽癌放疗后放射性脑病积极尽快治疗。     

鼻咽癌放疗后放射性脑病的磁共振氢波谱研究

目的 探讨鼻咽癌放疗后放射性脑病的磁共振氢波谱(1H-MRS)表现,了解N-乙酰天门冬氨酸(NAA)、肌酸(Cr)和胆碱(Cho)3种物质的代谢规律,为放射性脑病的早期诊断提供方法.方法 选取10例健康志愿者作为对照组,21例病理诊断为鼻咽癌并进行根治性放疗后经症状及影像学诊断为放射性脑病的病人作为病例组,用化学位移成像法(CSI)行1H-MRS检查.观察各像素中NAA、Cr和Cho的含量、代谢图及它们之间的比例.结果 磁共振成像(MRI)可见放射性脑病病灶中的液化坏死区3种物质含量基本为零,代谢图中无信号;病灶中非液化坏死区NAA轻度升高,Cr和Cho明显降低或为零,NAA代谢图呈高信号,Cr和Cho低信号.病灶周边存在一个区域NAA降低,Cf和Cho升高,NAA/Cr和NAA/Cho＜1,代谢图中信号区分不明显.远离可见病灶的区域NAA、Cr和Cho含量及比例正常.结论 1H-MRS可显示放射性脑病的物质代谢变化规律,发生变化的区域面积大于MRI中可见病变区,从而为该病的早期诊断提供了可能.     

放射性脑病发生的高危因素及MRI影像学改变研究

目的探讨放射性脑病(REP)发生的高危因素和MRI在REP早期诊断中的价值。方法回顾性分析我院近年106例REP患者的临床资料,将发病时间、照射疗程和剂量与MRI影像学检查相结合进行分析。结果 REP发病时间多集中在首次放疗后1～5年,射野上界在OM线上>2.5cm者及生物效应剂量(BED)>139Gy者易发生REP;15.09%的患者尚未出现明显神经系统损害表现时,MRI检查提示为T1WI等或低信号、T2WI高信号。结论对病人采取合理配比照射区域和次数可减少REP的发生,MRI检查有助于早期发现和诊断REP。     

鼻咽癌放疗后迟发性放射性脑病的PET/CT影像分型

目的 研究鼻咽癌放疗后放射性脑病(RE)的PET/CT影像学表现,观察大脑颞叶的代谢改变规律,根据其影像学表现进行分型.以期为放射性脑病的准确诊断提供诊断依据和标准.方法 本组共53例均为鼻咽癌(经活检病理确诊)行根治性放疗后,经过临床症状及CT和(或)MRI平扫加增强诊断为RE的患者.患者均依次进行全身和头部的扫描成像;并将临床资料与PET/CT影像学资料相结合进行分析.结果 最常见的放射性脑病累及的部位是双侧或单侧颞叶下极.本组中PET显示双侧颞叶代谢均明显降低者35例(即70个颞叶),单侧颞叶代谢减低者18例(即18个颞叶).根据PET/CT的影像学表现,将所有病例分为三型:水肿型(56个颞叶)、液化坏死型(10个颞叶)及萎缩钙化型(22个颞叶).1例水肿型的患者经过及时治疗后,病变区脑组织水肿完全恢复正常密度,代谢也恢复至正常;但2例水肿型进一步加重演变为萎缩钙化型;2例液化坏死型演变为萎缩钙化型.结论 根据RE的PET/CT表现将其分为水肿型、液化坏死型及萎缩钙化型共三型;第一、第二型可以向第三型演变.