Magnetic resonance imaging of intramedullary spinal cord metastases

In this report we describe the appearance of four intramedullary spinal cord metastases on T2-weighted and contrast-enhanced T1-weighted magnetic resonance images. The epidemiology, clinical presentation, and the use of magnetic resonance imaging in these rare lesions are discussed.     

Magnetic resonance imaging of orbital tumors

This contribution provides an overview of diseases of eye and orbit and their appearance on magnetic resonance imaging. In recent years the diagnosis of eye and orbit pathology has profited significantly from increasingly sophisticated technical developments in the field of tomographic methods. Due to the small size of the examination area the improvement in spatial resolution and soft tissue contrast leads to an increase in image quality. In most clinical questions concerning eye and orbit pathologies magnetic resonance imaging is superior to computed tomography and should be early performed.     

25例脊髓动静脉畸形治疗

目的　探讨脊髓髓内动静脉畸形的栓塞方法。方法　 2 5例脊髓髓内血管畸形患者 ,均行血管内栓塞治疗 ,早期 4例在肋间动脉或腰动脉直接注射硬脑膜颗粒或PVA等 ,近期 9例将微导管插至供血动脉远端以PVA栓塞 ,1例先以NBCA栓塞供血动脉上的动脉瘤 ,再以Embosphere栓塞AVM。 7例以NBCA栓塞。 5例直接手术切除病灶 ,2例栓塞联合手术治疗。结果　 2 0例栓塞后造影证实 12例几乎完全栓塞 ,8例为大部分栓塞 ,经半年～ 2年随访 ,16例临床症状均有不同程度改善 ,4例临床症状无明显变化 ,均未出现出血症状。结论　对于髓内幼稚型和不能手术的团块型AVM ,血管内栓塞治疗为首选治疗。     

Magnetic resonance imaging of mouse spinal cord.

The feasibility of performing high-resolution in vivo MRI on mouse spinal cord (SC) at 9.4 T magnetic field strength is demonstrated. The MR properties of the cord tissue were measured and the characteristics of water diffusion in the SC were quantified. The data indicate that the differences in the proton density (PD) and transverse relaxation time between gray matter (GM) and white matter (WM) dominate the contrast seen on the mouse SC images at 9.4 T. However, on heavily T(2)-weighted images these differences result in a reversal of contrast. The diffusion of water in the cord is anisotropic, but the WM exhibits greater anisotropy and principal diffusivity than the GM. The quantitative data presented here should establish a standard for comparing similar measurements obtained from the SCs of genetically engineered mouse or mouse models of SC injury (SCI).     

Magnetic resonance appearance of peripheral nerve sheath tumors

Magnetic resonance imaging (MRI) was used to evaluate 22 histologically proven peripheral nerve sheath tumors, approximately two-thirds of which arose in the lower extremity. The histologic distribution was as follows: 12 schwannomas, 7 neurofibromas, and 3 malignant peripheral nerve sheath tumors (2 of which occurred in patients with neurofibromatosis). Most lesions demonstrated an intermediate to moderately bright signal on T₁-weighted images and were minimally inhomogeneous. All lesions were moderately bright on proton-density-weighted images and bright on T₂-weighted images, again with variable inhomogeneity. The extent of the tumor was best assessed on proton-density- and T₂-weighted images. Smooth margins were noted in 19 lesions. Of the 3 remaining lesions, 2 were malignant (but had been subjected to biopsy prior to MRI), and the other lesion was a plexiform neurofibroma. MRI accurately determined the relationship between the lesion and the adjacent neurovascular structures and muscles, thereby assisting surgical management. On MRI, 5 lesions demonstrated coexistent subtle muscle atrophy along the longitudinal axis of surrounding or distally innervated musculature. This latter finding, together with the presence of a tumor in the vicinity of a large nerve trunk, suggests a peripheral nerve sheath neoplasm.The opinions and assertions contained herein are the private views of the authors and do not reflect the views of the Uniformed Services University of the Health Sciences, the Department of the Army, or of the Department of Defense     

Subpial schwannoma of the cervical spinal cord mimicking an intramedullary tumor

We report a rare case of a subpial schwannoma of the cervical cord mimicking an intramedullary tumor in a 65-year-old woman. The magnetic resonance imaging findings are presented and discussed.     

Intradural spinal tumors: current classification and MRI features

The differential diagnosis of intradural spinal tumors is primarily based on location, but the clinical presentation, age, and gender of the patient are also important factors in determining the diagnosis. This comprehensive review focuses on the current classification, clinical symptoms, and MRI features of the more common intradural extramedullary and intramedullary neoplastic lesions. This review does not include extradural lesions.     

MRI diagnosis of intramedullary metastases from extra-CNS tumors

The purpose of this study was to evaluate the topography, morphology and contrast enhancement of the intramedullary metastases (IM) from extra-CNS neoplasms. We report the results of a multicenter retrospective study on 18 patients with 26 IM examined with a 0.5T MR imaging system; intravenous injection of Gd-DTPA was performed in all cases. We found that the lesions are most frequently single, oval shaped, and small, with little or no deformation of the spinal cord (14 of 26 IM). They appear isointense on spin-echo T1-weighted images (24 of 26 IM), with a homogeneous and generally nodular high contrast enhancement after Gd-DTPA injection (21 of 26 IM), and present on T2- and proton-density-weighted sequences with a pronounced perilesional, pencil-shaped hyperintensity of the surrounding cord which is more evident in the cranial part of the cord referring to the IM.     

脊髓室管膜瘤的MRI表现

目的探讨脊髓内室管膜瘤的MRI表现,提高对本病的认识。方法收集我院经病理证实的脊髓室管膜瘤13例,分析肿瘤部位、信号特点、有无囊变、出血及帽征、椎间孔扩大及肿瘤强化方式。结果肿瘤位于颈髓6例,胸髓3例,终丝及马尾4例.在T1WI上呈等、低信号,在T2WI上呈高信号、混杂信号.9例见囊变,3例可见肿瘤内出血,2例椎间孔扩大.13例均出现不同程度强化,1例呈轻度强化,3例中度强化,9例重度强化,11例肿瘤与正常脊髓分界清楚。结论髓内室管膜瘤MRI表现具有一定特点,结合其发病部位、边界、囊变、出血、强化特征及临床资料常可作出正确诊断。     

脊髓血管母细胞瘤的MRI诊断与鉴别诊断

目的探讨脊髓血管母细胞瘤的MRI表现特征。方法回顾性分析8例经手术和病理证实的脊髓血管母细胞瘤的临床及MRI检查资料。结果6例单发,2例多发,所有病灶均位于脊髓内,颈髓及胸髓各5个,肿瘤多呈点状或结节状、香肠状、葫芦形或不规则形,壁结节MRT1WI呈等信号,T2WI呈稍高信号,增强后肿瘤呈显著强化,肿瘤常继发囊肿或大范围脊髓空洞以及水肿,大于lcm的肿瘤内部及周围常见流空血管影。结论脊髓血管母细胞瘤的MRI影像表现具有特征性,掌握这些MRI表现有利于提高脊髓血管母细胞瘤的诊断正确性。     

Magnetic resonance imaging of head and neck tumors

Magnetic resonance imaging (MRI) provides several advantages over computed tomography (CT) in the evaluation of head and neck region tumors. The improved soft-tissue contrast among normal and abnormal tissues provided by MRI now permits the exact delineation of tumor margins in the nasopharynx, oropharynx, and skull base regions. In addition, the ability to depict cross-sectional anatomy and pathology in three planes without intravenous contrast, patient manipulation, or ionizing irradiation is a distinct advantage of MRI over CT scanning. Drawbacks of MRI include the detection of subtle osseous abnormalities, patient motion, and artifacts introduced by ferromagnetic dental appliances. These drawbacks appear minimal when compared to the benefits of improved soft-tissue contrast and the ability to image exact tumor volumes.     

Magnetic resonance signal alterations in the acute onset of heterotopic ossification in patients with spinal cord injury

The purpose of our study was to evaluate magnetic resonance (MR) signal characteristics of acutely forming heterotopic ossification (HO) in paralyzed patients. Fourteen patients with spinal cord injury (female n=2, male n=12, mean age 38.3 years) and acute onset of radiographically proven HO had contrast-enhanced 1.5-T MRI within 13.4±18.3 days of clinical onset of symptoms. MR signal alterations of affected muscles, fascia, subcutaneous tissue, skin and adjacent bone were evaluated. A diffuse T2-hyperintense signal of multiple muscle groups was seen in all patients (bilateral in 12) involving quadriceps (n=13, 93%), adductors (n=13, 93%) and iliopsoas (n=12, 86%) with contrast enhancement in n=11 (79%), n=8 (57%) and n=8 (57%) patients. All patients had nonenhancing areas (mean size 2×3.5×5.8 cm) within diffusely enhancing muscles. HO formation occurred around these nonenhancing areas in four patients with computed tomography follow-up. Other MR findings included fascial edema (n=14, 100%), fascial enhancement (n=13, 93%), subcutaneous edema (n=13, 93%), subcutaneous enhancement (n=12, 86%), bone marrow edema (n=5, 36%), and joint effusion (n=12, 86%). MRI reveals mostly bilateral edema and enhancement of muscles, fascia and subcutaneous tissue during acute onset of HO. HO develops in the periphery of well-defined areas of no enhancement.     

肺癌脊髓内转移的MRI诊断

目的：探讨肺癌脊髓内转移（ISCM）的MRI表现特征及病理机制。方法：对3例经手术病理证实及4例临床确诊的肺癌脊髓内转移的MRI表现进行回顾性分析。全部病例均行MRI平扫及钆喷替酸葡甲胺（Gd-DTPA）增强扫描。结果：7例转移瘤均为单发，3例位于胸段，4例位于脊髓圆锥部。主要MRI表现：肿瘤均位于脊髓中央，T1WI1例呈低信号，6例呈等信号，T2WI全部为高信号，病灶上下方髓内可见水肿2例，空洞3例；平扫肿瘤边界模糊不清，增强扫描均呈明显强化，其中3例呈不均匀强化，3例呈环形强化，1例呈结节样强化，增强后肿瘤边界显示十分清楚。结论：肺癌脊骨转移的MRI表现常为明显强化的髓内肿物，但其缺乏特征性，定性诊断需结合临床资料综合分析。     

肿瘤MR分子影像学研究进展

MR分子影像学以分子生物学为基础,借助MRI技术在活体状态下从分子、基因水平对肿瘤进行更早期、更特异性诊断与监测治疗效果。目前关于MR分子影像研究多集中于MR特异性分子探针的制备、肿瘤血管形成显像、报告基因显像、波谱显像等方面,由于MR具有精确的空间定位及功能成像等优势,因此在肿瘤分子影像研究中具有极大的发展潜力,将在21世纪肿瘤的诊断与治疗中发挥重要作用。MR分子影像学以分子生物学为基础,借助MRI技术在活体状态下从分子、基因水平对肿瘤进行更早期、更特异性诊断与监测治疗效果。目前关于MR分子影像研究多集中于MR特异性分子探针的制备、肿瘤血管形成显像、报告基因显像、波谱显像等方面,由于MR具有精确的空间定位及功能成像等优势,因此在肿瘤分子影像研究中具有极大的发展潜力,将在21世纪肿瘤的诊断与治疗中发挥重要作用。     

Magnetic resonance imaging of acute spinal cord injury

Summary Magnetic resonance imaging of acute spinal cord injury is described. The traumatized cord segment was clearly shown as a hyperintensity in a T2-weighted image whereas it appeared as an isointensity in a moderately T1-weighted image. This different sensitivity may result from parenchymal hemorrhagic tissue and edematous changes due to direct trauma. Hyperintense tissue was also seen in the retro-pharyngeal and-tracheal spaces.     

Intraoperative sonography of intramedullary spinal cord tumóurs

Summary Intraoperative spinal sonography was performed 23 times in 20 patients with intramedullary spinal cord tumours, and the sonographic features were examined. Eight cases of astrocytoma were classified into three types: type 1, seen in 3 children, had intramedullary, circular or oval, hyperechogenic multiple tumour shadows; type 2 presented inter-multimyelomere, relatively well-defined single tumour shadows corresponding to grade III and I for two juvenile and aged cases each, respectively; and type 3 appeared ill-defined and diffusely infiltrating. The relationships between these types, the ages of patients and histological grades were considered a potential clue to mechanisms of occurrence and infiltration of astrocytoma. All 7 ependymomas had syrinxes, of three types; central canal was very large, the tumour lying within it like an island; or the tumour was in contact with a cephalocaudal side part of the syrinx; or the tumour had a syrinx or cyst. Songraphic images thus differ according to the tumour, but differential diagnosis is currently limited. Development of sonographic equipment, with upgrading its resolving power are hoped for.     

Magnetic resonance imaging contribution to the diagnosis of spinal cord compression by a subdural arachnoid cyst

Summary A case of subdural arachnoid cyst of the thoracic spine was studied by magnetic resonance imaging (MRI), myelography and CT myelography. Myelography and especially CT myelography suggested the diagnosis; MRI established it, showing the communication between the cyst and the subarachnoid space. Final characterization was based on surgical findings and pathological examination.     

Magnetic resonance angiography of rat spinal cord at 9.4 T: a feasibility study.

In this study we investigated the feasibility of performing 3D time-of-flight magnetic resonance angiography to remotely image the arteries of rat spinal cord. Using a custom-designed implantable radiofrequency coil, we acquired angiograms from normal and injured cords. The potential of the approach was evaluated in terms of longitudinally monitoring the vascular reorganization of spinal cord following an injury.     

Magnetic resonance imaging in the assessment of cystic pancreatic lesions: differentiation of benign and malignant lesion status

Purpose: To characterize cystic pancreatic lesions and tumors with magnetic resonance imaging (MRI), and to assess the value of morphological criteria in differentiating pseudocysts versus cystic tumors and benign versus malignant cystic tumors.

Material and Methods: Twenty-three patients with cystic pancreatic tumors or lesions underwent plain and contrast-material-enhanced MRI, including magnetic resonance cholangiopancreatography (MRCP). The MR findings were characterized and analyzed by two readers, and the role of various imaging criteria and combinations thereof for final lesion assignment were assessed. Final diagnoses were obtained from the results of open surgery (n = 19) and/or biopsy (n = 4).

Results: Final diagnoses included cystic tumors (n = 11) and pseudocysts (n = 12). The lesions were located in the head (56%) and body or tail (44%). Lesion diameters ranged from 7 to 50 mm. Various lesion contrast enhancement patterns were observed for both benign and malignant lesions. Serous cystadenomas were located in the head, they were lobulated, and had wall diameters≤2 mm; with the combination of these characteristics all patients with serous cystadenoma could be identified, whereas in no other patient was this constellation observed.

Conclusion: MRI facilitated the diagnosis of serous cystadenomas, although no definite morphologic criterion for the differentiation between pseudocysts and mucinous cystadenomas was identified. In consideration of the substantial therapeutic consequences, either diagnostics in unclear cystic pancreatic lesions should comprise cyst fluid analysis if necessary, or eligible patients should be referred for surgical resection.