Surrounding muscle edema detected by MRI is valuable for diagnosis of intramuscular myxoma

We recently experienced 4 cases of intramuscular myxoma and analyzed MRI findings, comparing them with histological ones. Results showed that all tumors were depicted with a homogeneous low signal intensity on T1-weighted images and a markedly high signal intensity on T2-weighted images, findings which are similar to those of cystic lesions like intramuscular ganglions. However, tumors were diffusely and finely enhanced on T1-weighted images with intravenous gadolinium administration. Three cases showed the characteristic fat rim and fat cap. A diffuse edematous lesion demonstrating intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images was also found in the adjacent muscle surrounding the tumor in 3 of 4 cases. In this lesion, tumor invasion, diffuse and severe muscle degeneration, blood and lymphatic congestion with exudates, and reactive adipose tissue formation were observed. The present results suggested that for the clinical diagnosis of intramuscular myxoma with MRI examination, the combination of three MRI signs such as homogeneous low signal intensity on T1-weighted mages, markedly high signal intensity on T2-weighted images, and an enhancement effect with contrast medium are important, but the fat rim or fat cap, and the surrounding muscle edema as detected by MRI are also characteristic and allow for a more firm diagnosis. We presume that the diffuse and severe muscle fiber degeneration induced by tumors may cause such specific surrounding muscle edema.     

Human herpesvirus-6 encephalitis after unrelated cord blood transplantation

Here we describe 2 patients with acute leukemia in whom human herpesvirus-6 (HHV-6) encephalitis developed after cord blood transplantation. In patients 1 and 2, generalized seizure and coma developed on day 62 and day 15, respectively, after cord blood transplantation, which failed to engraft in patient 1. Magnetic resonance imaging (MRI) of patient 1's brain showed low-intensity signals at the gyri of the bilateral lateral lobes on T1-weighted images and high-intensity signals on T2-weighted images. MRI of patient 2's brain showed high-intensity signals in bilateral white matter on T2-weighted images and on fluid-attenuated inversion recovery (FLAIR) images. Cerebrospinal fluid examination revealed an increased protein level with pleocytosis in patient 1 and a normal protein level without pleocytosis in patient 2. Polymerase chain reaction analysis detected HHV-6 DNA in the cerebrospinal fluid of both patients. Patient 1 recovered after administration of gancyclovir for 3 weeks. However, she again suffered from encephalitis after discontinuation of gancyclovir, and died of sepsis. Patient 2 died from an anoxic brain caused by generalized seizure. When neurological symptoms and signs appear in hematopoietic stem cell transplantation recipients, we should consider HHV-6 encephalitis and promptly and empirically treat them with gancyclovir or foscarnet.     

原发性软组织恶性纤维组织细胞瘤的MRI影像诊断(附15例报告)

目的:探讨原发性软组织恶性纤维组织细胞瘤(MFH)的MRI影像诊断。方法:回顾性分析15例经手术病理证实的原发于软组织的恶性纤维组织细胞瘤患者的影像学资料,15例患者均行MRI检查,有7例行CT检查,8例行增强扫描。结果:原发于软组织恶性纤维组织细胞瘤15例,肿瘤形态多样,以卵圆形、分叶状多见。病变于T1WI呈低信号或等信号,T2WI呈高信号或等信号为主混杂信号影,7例病变内可见低信号之分隔影。13例病变内见坏死或黏液样改变,2例伴出血。明确有包膜3例。增强扫描均呈显著不均匀强化。结论:MRI对原发性软组织恶性纤维组织细胞瘤的诊断具有重要价值,是首选的影像学检查方法。     

滑膜肉瘤MRI影像特征与组织病理学的相关性研究

背景与目的：磁共振成像(magnetic resonance imaging,MRI)是检查软组织肿瘤最好的影像学方法。滑膜肉瘤是常见的恶性软组织肿瘤之一,本研究探讨滑膜肉瘤的MRI影像特征与病理组织学的相关性．以期提高MRI对该肿瘤的诊断水平。材料和方法：12例滑膜肉瘤均经手术病理证实,位于上肢2例,位于下肢lO例;患者年龄35～50岁,中位年龄45岁;男女比例为3：1。MRI扫描采用PHILIPS GYROSCAN 0．5T超导型磁共振成像系统．扫描序列采用SE、FSE、FFE和Stir等序列,所有病例均作T,WI、T2WI和T1W Gd-DTPA静脉内注射增强扫描检查。取手术标本进行病理学检查,比较滑膜肉瘤MRI影像学表现与病理组织学的关系。结果：MRI可见12例肿块均位于关节旁,其中2例向关节内侵犯,3例侵犯邻近的骨质。在T1W12例肿块均呈以等信号为主的肿块．但其中3例肿块可见部分斑片状和囊状高信号区。在T2W6例肿块信号表现为三重信号;6例肿块表现为多结节状,3例呈不规则状,3例为圆形或椭圆形肿块。5例肿瘤内可见分隔征象,液-液平面征l例,肿块最大直径3～13cm。T1WGd-DTPA增强肿块均呈明显不均匀性强化。12例滑膜肉瘤病理分型：低分化单相梭形细胞为主型7例,高分化3例;双相分化2例。肿块内有大范围出血和囊性变6例,大量瘤组织坏死5例,钙化2例。结论：滑膜肉瘤的MRI具有一些特征性,并和肿瘤的组织学类型具有一定相关性。     

Evaluation of lymph node metastases in gastric cancer using magnetic resonance imaging with ultrasmall superparamagnetic iron oxide (USPIO): diagnostic performance in post-contrast images using new diagnostic criteria

Background  We assessed the value of magnetic resonance imaging (MRI), using ultrasmall superparamagnetic iron oxide (USPIO) with new diagnostic criteria, in the evaluation of regional lymph node metastases in gastric cancer. Methods  Thirty-one patients with gastric cancer were enrolled. 1000 lymph nodes were dissected during surgery, and of these, 519 nodes (51.9 %) were identified by currently used MRI imaging analysis. We evaluated lymph nodes on USPIO-post-contrast T2*-weighted images using the following two criteria: (1) we diagnosed the nodes on T2*-weighted images according to conventional criteria, where a node having an overall low signal intensity (pattern A) was nonmetastatic, while a node having partial (pattern B) or overall (pattern C) high signal intensity was metastatic; (2) we subdivided pattern B nodes on T1-weighted images using the new criteria, in which a node for which the high-intensity area on T2*-weighted images was not defined as adipose tissue on T1-weighted images (pattern B1) was metastatic, while a node for which the high-intensity area was defined as adipose tissue (pattern B2) was nonmetastatic. Results  (1) The results using the conventional criteria were 96.2% sensitivity, 92.5% specificity, 76.3% positive predictive value (PPV), 99.0% negative predictive value (NPV), and 93.3% accuracy. (2) The results using the new criteria were 96.2% sensitivity, 98.3% specificity, 90.1% PPV, 99.0% NPV, and 97.1% accuracy. Conclusion  The assessment of lymph node metastases from USPIO-post-contrast MRI alone using the new criteria was useful in the diagnosis of regional lymph node metastases in gastric cancer.     

富血供肝转移瘤的MRI表现和特点

背景与目的：肝脏是血源性转移癌最好发的器官，正确判断富血供肝转移瘤具有重要的临床价值，本研究探讨富血供肝转移瘤的MRI特征。方法：回顾性分析122例有明确原发肿瘤病史并伴有肝脏转移的病例。根据强化程度，当病灶显示出明显的早期强化（强化程度与胰腺或肾皮质相仿）时，肝转移瘤被认为是富血供的，据此，共有31例符合人选标准，其中男性8例，女性23例，年龄29～77岁，平均年龄51．9岁。所有31例均行上腹部MRI检查（采用1．5T超导MR扫描仪），扫描序列包括T2WIFSE序列，T1WISPGR序列（用于增强前后扫描）。对比剂为钆喷酸葡胺注射液（Gd—DTPA），注射剂量为0．1mmol/kg，注射速率为2ml／s，注射后行Ⅲ期扫描，扫描时间分别为：20、45、90S。所有MR图像由两位有经验的放射科高年主治医师分析并达成一致。结果：31例患者共发现239个肝转移灶，分布于两叶，无特别好发肝段。其中21例转移灶为多发，其余10例为单发转移灶。病灶小于9．5cm。MR图像显示所有病灶于T1WI均为低信号。在T2WI图像上，127个病灶（53％）显示为中等高信号，65个病灶（27％）为中等高信号伴病灶中央更高信号区。增强动脉期显示183个病灶（77％）呈明显的边缘强化，41个病灶（17％）呈弥漫均匀的结节样强化，15个病灶（6％）呈弥漫不均匀强化。增强门脉期，131个病灶表现为与动脉期相仿的强化方式与程度，其中33个病灶表现为较动脉期稍增厚的强化环。结论：根据富血供肝转移瘤的主要特征．大多数病灶可以和肝脏其他富血供病变（如HCC．血管瘤，FNH等）能正确鉴别。     

Quantitative T2 mapping of recurrent glioblastoma under bevacizumab improves monitoring for non-enhancing tumor progression and predicts overall survival

Background

Anti-angiogenic treatment in recurrent glioblastoma patients suppresses contrast enhancement and reduces vasogenic edema while non-enhancing tumor progression is common. Thus, the importance of T2-weighted imaging is increasing. We therefore quantified T2 relaxation times, which are the basis for the image contrast on T2-weighted images.

Methods

Conventional and quantitative MRI procedures were performed on 18 patients with recurrent glioblastoma before treatment with bevacizumab and every 8 weeks thereafter until further tumor progression. We segmented the tumor on conventional MRI into 3 subvolumes: enhancing tumor, non-enhancing tumor, and edema. Using coregistered quantitative maps, we followed changes in T2 relaxation time in each subvolume. Moreover, we generated differential T2 maps by a voxelwise subtraction using the first T2 map under bevacizumab as reference.

Results

Visually segmented areas of tumor and edema did not differ in T2 relaxation times. Non-enhancing tumor volume did not decrease after commencement of bevacizumab treatment but strikingly increased at progression. Differential T2 maps clearly showed non-enhancing tumor progression in previously normal brain. T2 relaxation times decreased under bevacizumab without re-increasing at tumor progression. A decrease of <26 ms in the enhancing tumor following exposure to bevacizumab was associated with longer overall survival.

Conclusions

Combining quantitative MRI and tumor segmentation improves monitoring of glioblastoma patients under bevacizumab. The degree of change in T2 relaxation time under bevacizumab may be an early response parameter predictive of overall survival. The sustained decrease in T2 relaxation times toward values of healthy tissue masks progressive tumor on conventional T2-weighted images. Therefore, quantitative T2 relaxation times may detect non-enhancing progression better than conventional T2-weighted imaging.     

Magnetic resonance imaging of brain tumors

Magnetic resonance imaging (MRI) has been applied to the diagnosis of brain tumors very widely and MRI is now replacing computed tomography (CT). One of the most important advantages of MRI is influence of multiple tissue and machine parameters on the signal intensities. In addition, capability of imaging in various planes and multislices is another advantage for the brain tumor diagnosis. The coronal image is important when the abnormal side can be compared with the normal side and midline lesions can be easily diagnosed with sagittal imaging. Transverse imaging is important when comparison is made with CT. Many brain tumors show increased signal intensity on T2-weighted images and decreased signal intensity on T1-weighted images and decreased signal intensity on T1-weighted images. The difference of signal intensity in various brain tumors including glioma, meningioma and other important tumors are discussed. MRI is superior to CT in many brain tumors, but poor delineation of calcification and hemorrhage is a disadvantage of MRI.     

原发性软组织恶性纤维组织细胞瘤的MRI影像诊断（附15例报告）

目的：探讨原发性软组织恶性纤维组织细胞瘤（MFH）的MRI影像诊断。方法：回顾性分析15例经手术病理证实的原发于软组织的恶性纤维组织细胞瘤患者的影像学资料,15例患者均行MRI检查,有7例行CT检查,8例行增强扫描。结果：原发于软组织恶性纤维组织细胞瘤15例,肿瘤形态多样,以卵圆形、分叶状多见。病变于T1WI呈低信号或等信号,T2WI呈高信号或等信号为主混杂信号影,7例病变内可见低信号之分隔影。13例病变内见坏死或黏液样改变,2例伴出血。明确有包膜3例。增强扫描均呈显著不均匀强化。结论：MRI对原发性软组织恶性纤维组织细胞瘤的诊断具有重要价值,是首选的影像学检查方法。     

脑实质内室管膜瘤的MRI表现与病理结果比较分析

目的 比较脑实质内室管膜瘤的MRI表现与病理结果.方法 对经手术病理证实的30例脑实质内室管膜瘤进行回顾性分析,均行颅脑MRI平扫及增强扫描检查.结果 肿瘤大小:长径2.0~13.0 cm,平均(5.16±2.03)cm.7例发生于幕上;发生于幕下23例.所有病例伴幕上不同程度脑积水.发病男性18例(60.00%),女性12例(40.00%).发病年龄≤14岁6例(20.00%);>14岁24例(80.00%).Ⅰ~Ⅱ级21例,占比70.00%;Ⅲ级9例,占30.00%.幕上Ⅰ~Ⅱ级5例,Ⅲ级2例,幕下Ⅰ~Ⅱ级16例,Ⅲ级7例.手术全切21例(70.00%);进行手术大部分切除9例(30.00%).MRI表现:T1加权像上,长T1:等T1:短T1:混杂信号=16:4:2:8;T2加权像上,长T2:等T2:混杂信号=18:2:10;肿瘤内部信号均匀者6例,不均匀者24例,其中有16例出现肿瘤内囊变;肿瘤边界清晰者7例,边界欠清晰者23例;瘤周无明显水肿者22例,7例轻度水肿,1例重度水肿;肿瘤无强化者4例,强化者26例,其中不均匀强化者25例.MRI诊断准确率(83.3%)和病理确诊比较,差异无统计学意义(P>0.05).结论 MRI能较清楚显示室管膜瘤病灶,对诊断及鉴别脑实质内室管膜瘤具有重要价值.     

Comparison of MRI pulse sequences in defining prostate volume after permanent implantation

PURPOSE: To determine the relative value of three MRI pulse sequences in defining the prostate volume after permanent implantation. METHODS AND MATERIALS: A total of 45 patients who received a permanent 125I implant were studied. Two weeks after implantation, an axial CT scan (2 mm thickness) and T1-weighted, T1-weighted fat saturation, and T2-weighted axial MRI (3-mm) studies were obtained. The prostate volumes were compared with the initial ultrasound planning volumes, and subsequently the CT, T1-weighted, and T1-weighted fat saturation MRI volumes were compared with the T2-weighted volumes. Discrepancies in volume were evaluated by visual inspection of the registered axial images and the registration of axial volumes on the sagittal T2-weighted volumes. In a limited set of patients, pre- and postimplant CT and T2-weighted MRI studies were available for comparison to determine whether prostate volume changes after implant were dependent on the imaging modality. RESULTS: T1-weighted and T1-weighted fat saturation MRI and CT prostate volumes were consistently larger than the T2-weighted MRI prostate volumes, with a volume on average 1.33 (SD 0.24) times the T2-weighted volume. This discrepancy was due to the superiority of T2-weighted MRI for prostate definition at the following critical interfaces: membranous urethra, apex, and anterior base-bladder and posterior base-seminal vesicle interfaces. The differences in prostate definition in the anterior base region suggest that the commonly reported underdose may be due to overestimation of the prostate in this region by CT. The consistent difference in volumes suggests that the degree of swelling observed after implantation is in part a function of the imaging modality. In patients with pre- and postimplant CT and T2-weighted MRI images, swelling on the T2-weighted images was 1.1 times baseline and on CT was 1.3 times baseline, confirming the imaging modality dependence of prostate swelling. CONCLUSION: Postimplant T2-weighted MRI images provided superior prostate definition in all critical regions of the prostate compared with CT and the other MRI sequences tested. In addition to defining an optimal technique, these findings call two prior observations into question. Under dosing at the anterior base region may be overestimated because of poor definition of the prostate-bladder muscle interface. The swelling observed after implantation was lower on T2-weighted images as well, suggesting that a fraction of postimplant swelling is a function of the imaging modality. These findings have implications for preimplant planning and postimplant evaluation. As implant planning techniques become more conformal, and registration methods become more efficient, T2-weighted MRI after implantation will improve the accuracy of postimplant dosimetry.     

Magnetic resonance imaging anatomy of the prostate and periprostatic area: a guide for radiotherapists.

Magnetic resonance imaging (MRI) offers superb soft tissue contrast on T2-weighted images and allows direct multiplanar image acquisition. It can show the internal prostatic anatomy, prostatic margins, and the extent of prostatic tumors in much more detail than computed tomography (CT) images. The present article reviews some key prostatic and periprostatic radiologic landmarks that can be helpful for the radiotherapist using T2-weighted MRI as an adjunct to CT in treatment planning for prostate cancer.     

3T MRI in evaluation of asbestos-related thoracic diseases - preliminary results

Background

3T high-field magnetic resonance imaging (MRI) scanners have recently become available for the clinical use and are being increasingly applied in the field of whole-body imaging and chest imaging as well. The aim of this study was to evaluate the diagnostic potential of 3 T MRI as a complementary imaging modality to CT in detecting the pathological changes of asbestos-related thoracic diseases.

Patients and methods

Fifteen patients with the asbestos-related thoracic disease were scheduled for 3T MRI. Five had a benign form of the disease and 10 had malignant pleural mesothelioma (MPM). From the patients with a benign form of the disease their last CT examination in digital form was acquired and patients with MPM were scheduled for CT examination with contrast media. The protocol of MR imaging consists of T2-weighted cardiac-gated breath-hold turbo spin echo (TSE) sequences in coronal, sagittal and axial plane and T1-weighted cardiac-gated breath-hold TSE black blood in axial plane. In T2-weighted sequences in axial plane, fat saturation was also used. CT examinations were obtained with the administration of the contrast medium from lung apices to the lower end of the liver. Images of 5 mm (mediastinum window) and 3 mm (lung window) in axial plan were reconstructed. MRI signal intensity of lesions and adjacent muscles on Syngo MultiModality Work Place were measured.

Results

Compared to muscles pleural plaques appeared hypo-intense to iso-intense on T1 weighted images (in 100%) and also hypo-intense on T2 fs-weighted images (in 100%). MPM appeared inhomogeneous hypo-intense to iso-intense on T1-weighted and hyperintense on T2 fs-weighted images in all patients (100%).

Conclusions

These preliminary results pointed out that MRI was equal or even better compared with CT examination for detecting possible malignant potential of pleural changes in the asbestos-related pleural disease, using signal intensity measurements of T2 fs-weighted images. The 3T MRI enabled the accurate determination of chest pathology and it could be used for imaging of patients with the asbestos-related thoracic disease. MRI is particularly valuable because a patient is not exposed to the harmful radiation which is important if imaging methods are used repeatedly, like in screening programs or in monitoring of treatment results. This finding turned us to propose 3T MRI imaging technique as a non-ionizing imaging method for the follow-up of patients with the isolated pleural form of the asbestos-related disease.     

The value of F-18-fluorodeoxyglucose PET for the 3-D radiation treatment planning of malignant gliomas

Purpose: The aim of the study was to determine the impact of positron emission tomography using the glucose analogue fluorine-18-fluorodeoxyglucose (FDG-PET) on the delineation of the target volume in three-dimensional radiation treatment planning of primary brain tumors.

Methods and Materials: In 18 patients with histologically proven (8× biopsy, 10× subtotal resection) primary brain tumors (8 astrocytomas °III, one mixed glioma °III, and 9 glioblastomas), magnetic resonance imaging (MRI) with gadolinium-DTPA and FDG-PET were performed in radiation treatment position within the same week. A computer program was developed for fusion of the PET and MR images. On corresponding axial slices, FDG uptake was compared to contrast enhancement in T1-weighted and to signal hyperintensity in T2-weighted MR images. Based on PET and MRI data, three-dimensional treatment planning was performed. All patients underwent linear accelerator (LINAC) radiotherapy.

Results: In MRI, all tumors and the surrounding edema were visible as hyperintense lesions in the T2-weighted images. 17/18 tumors showed contrast enhancement. In FDG-PET, 16 tumors showed hypermetabolism compared to normal white matter, whereas only 8/18 tumors showed hypermetabolism compared to normal gray matter. White matter edema was associated with decreased FDG uptake in all patients. The area of increased FDG uptake correlated closely with contrast enhancement, only in one case the volume of increased FDG uptake was larger than the area of contrast enhancement. Mean tumor volumes obtained by MRI T1 + Gd, T2, and PET were 30, 106, and 10 ml, respectively. Survival was comparable to data in the literature with a 1-year survival of 39% and a median survival of 310 days.

Conclusion: Only in a minority of patients did FDG-PET provide additional information for radiation treatment planning. This is mainly caused by the high intensity of FDG uptake in normal brain tissue. PET may be of greater value in the definition of regions that should obtain a radiation dose boost.     

Ⅰ、Ⅱ期子宫内膜癌MRI表现与病理对照研究

Objective： To analyze MRI features of FIGO stage Ⅰ and Ⅱ endometrial carcinoma and to study the value of MRI in assessing myometrial and cervical invasion of endometrial carcinoma. Methods： Thirty patients with surgicopathologically proven endometrial carcinoma were included in this retrospective study. All patients underwent Tl-weighted spin-echo, T2-weighted fast spin-echo and dynamic contrastenhanced fast multiplanar spoiled gradient echo sequences before surgery. The type, signal intensity and enhancement features of the tumors and the appearance of junctional zone or subendometrial enhancement were analyzed. The MRI diagnosis of myometrial and cervical invasion was correlated with pathologic findings.Results： Endometrial carcinoma demonstrated diffuse widening of endometrial stripe （n=14） or polypoid or large mass in the endometrial cavity （n=16）. The tumors were usually isointense relative to the myometrium on TlWI and hyperintensity on T2WI. In the first phase of dynamic contrast-enhanced sequences, diffuse endometrial carcinoma usually showed mild （n=8） or moderate （n=5） enhancement, while focal endometrial carcinoma tended to enhance markedly （n=6） or moderately （n=9）. On T2WI junctional zone was seen in 18 cases. On dynamic contrast-enhanced images subendometrial enhancement was seen in 17 cases. The sensitivity, specificity and diagnostic accuracy of dynamic contrast-enhanced images in combination with T2WI were 87.5%, 95.5% and 93.3% for assessing deep myometrial invasion, and 75%, 95.5% and 90% for assessing cervical invasion. Conclusion： MRI is accurate and reliable in the evaluation of myometrial and cervical invasion of endometrial carcinoma, and should be performed as preoperative routine examination.     

Reliability of diffusion weighted MR imaging in differentiating degenerative and infectious end plate changes

Background

The aim of the study was to investigate the value of diffusion weighted MR imaging in the diagnosis of Modic type 1 change, which may be confused with the acute infectious spondylodiscitis on conventional MR imaging.

Patients and methods

Twenty-seven patients with erosive intervertebral osteochondrosis, Modic type 1 and 18 patients with spondylodiscitis were included in this retrospective study. All images were acquired using on 1.5 Tesla MR units. Lumbar spinal MR imaging of 45 patients were retrieved from a digital database of a radiology record system and evaluated by one experienced radiologist. Patients with Modic type 1 change had CT slices obtained from the diseased disc space and the affected vertebrae.

Results

Bone marrow adjacent to the vertebral end plate in both Modic type 1 change and acute spondylodiscitis were hypointense on T1-weighted images. On T2-weighted images corresponding levels of vertebral end-plates showed hyperintense signal intensity in both group. All the patients with spondylodiscitis and Modic type 1 change were hyperintense and hypointense on diffusion-weighted MR images, respectively.

Conclusions

Our findings suggest that diffusion weighted MR imaging is an useful method in differentiating Modic type 1 changes from acute spondylodiscitis, both of which may mimic each other, either on clinical or conventional MRI findings.     

纤维板层型肝癌的影像学表现

目的 观察纤维板层型肝癌（ＦＬ－ＨＣＣ）的影像学表现。方法 １１例ＦＬ－ＨＣ互病理证实。做超声波（ＤＳ）检查１０例,ＣＴ扫描１１例,ＭＲＩ８傲因管造影９例。结果 ＵＳ显示肿瘤呈高回声４例,混杂回声６例,４例有大小不一的囊性区,ＤｏｐｐｌｅｒＵＳ提示肿瘤实性部分血供丰富。ＣＴ显示肿瘤单发９例,多个结节融合２例,平扫均为低密度,７例肿块中心区见放射状更低密度区,病理检查为致密胶原瘢痕,４例见点状钙化,     

儿童原始神经外胚叶肿瘤的临床特征(附4例临床报告及文献复习)

目的 探讨儿童大脑神经外胚叶肿瘤的临床特点及治疗方法。方法 对我院1999年1月至2003年1月收治的4例小儿大脑神经外胚叶肿瘤的临床资料进行回顾性分析。结果 4例病人1例位于额叶，2例位于顶叶，1例位于颞叶。OT显示为高或等密度影，MRI为短TI长T2信号，增强后均匀强化，肿瘤有明显界线。4例均在显微镜下全切，病理诊断：原始神经外胚叶肿瘤。术后均行放疗。术后8个月～18个月复发。结论 小儿大脑原始神经外胚叶肿瘤为高度恶性的肿瘤，预后差手术加放疗能延长生存时间。     

Comparative Study of Images with Pathology： Superparamagnetic Iron Oxide-enhanced Magnetic Resonance Image （MRI） of Splenic VX2 Tumor in Rats

Objective： To establish a rodent model of VX2 tumor of the spleen, to analyze relationship between the change of the signal intensity on superparamagnetic iron oxide enhanced magnetic resonance image （MRI） and pathologic change to evaluate the ability of superparamagnetic iron oxide enhanced MRI for detection of splenic metastases. Methods： 8 rodent models of VX2 tumor of spleen were established successfully. The images were obtained before and after administration of superparamagnetic iron oxide. T1-weighted spin-echo （SE） pulse sequence with a repetition time （TR） of 450 msec, and echo time （TE） of 12 msec （TR/TE=450/12） was used. The imaging parameters of T2-weighted SE pulse sequence were as follows： TR/TE=4000/128. Results： On plain MR scanning T1-weighted splenic VX2 tumor showed hypointensity or isointensity which approximated to the SI of splenic parenchyma. Therefore all lesions were not displayed clearly. On superparamagnetic iron oxide enhancement T2WI sequence the SI of splenic parenchyma decreased obviously with percentage of signal intensity loss （PSIL） of 55.04%, But the SI of tumor was not evidently changed with PSIL of 0.87%. Nevertheless the SNR of normal splenic parenchyma around the lesions had obvious difference （P〈0.001） comparatively. Therefore the contrast between tumor and spleen increased, and tumor displayed more clearly. Moreover the contrast-to-noise （CNR） between VX2 tumor and splenic parenchyma had an evident difference before and after admininstration of superparamagnetic iron oxide （P〈0.001）. Conclusion： On superparamagnetic iron oxide enhancement T1WI sequence the contrast of tumor-to-spleen is poor. Therefore it is not sensitive to characterize the lesions in spleen. On superparamagnetic iron oxide enhanced T2WI the contrast degree of lesions increases obviously. Consequently, superparamagnetic iron oxide -enhanced T2WI MRI scanning can improve the rate of detection and characterization for lesions of spleen.     

Peribiliary liver metastases MR findings

We described magnetic resonance (MR) features of peribiliary metastasis and of periductal infiltrative cholangiocarcinoma. We assessed 35 patients, with peribiliary lesions, using MR 4-point confidence scale. T1-weighted (T1-W), T2-weighted (T2-W) and diffusion-weighted images (DWI) signal intensity, enhancement pattern during arterial, portal, equilibrium and hepatobiliary phase were assessed. We identified 24 patients with periductal-infiltrating cholangiocellular carcinoma. The lesions in 34 patients appeared as a single tissue, while in a single patient, the lesions appeared as multiple individual lesions. According to the confidence scale, the median value was 4 for T2-W, 4 for DWI, 3.6 for T1-W in phase, 3.6 for T1-W out phase, 3 for MRI arterial phase, 3.2 for MRI portal phase, 3.2 for MRI equilibrium phase and 3.6 for MRI hepatobiliary phase. According to Bismuth classification, all lesions were type IV. In total, 19 (54.3%) lesions were periductal, 15 (42.9%) lesions were intraperiductal, and 1 (2.8%) lesion was periductal intrahepatic. All lesions showed hypointense signal in T1-W and in ADC maps and hyperintense signal in T2-W and DWI. All lesions showed a progressive contrast enhancement. There was no significant difference in signal intensity and contrast enhancement among all metastases and among all metastases with respect to CCCs, for all imaging acquisitions (p value >0.05). MRI is the method of choice for biliary tract tumors thanks to the possibility to obtain morphological and functional evaluations. T2-W and DW sequences have highest diagnostic performance. MRI does not allow a correct differential diagnosis among different histological types of metastasis and between metastases and CCC.