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131.
对10例经手术证实的肝包虫囊肿(又称细粒棘球蚴病)的磁共振成像(MRI)进行分析,认为其特征性表现为:囊壁呈光滑厚薄均一的低信号的包膜,在T2加权像上显示更加清楚;母囊内有数个大小不等的子囊,整个病灶呈多房性似玫瑰花状。本文对肝包虫囊肿与肝内其它囊性占位病变的鉴别诊断进行了探讨。 相似文献
132.
S. Takahashi K. Ishii K. Matsumoto S. Higano T. Ishibashi M. Suzuki K. Sakamoto 《Neuroradiology》1994,36(5):337-339
We reviewed 12 cases of infarcts in the territory of the anterior choroidal artery (AChA) on CT and/or MRI. In each case vascular occlusion in the region was verified angiographically. Although the extent of the lesion on CT/MR images was variable, all were located on the axial images within an arcuate zone between the striatium anterolaterally and the thalamus posteromedially. The distribution of the lesions on mutiplanar MRI conformed well to the territory of the AChA demonstrated microangiographically. The variability of the extent of the infarcts may be explained by variations in the degree of occlusive changes in the AChA or the development of collateral circulation through anastomoses between the AChA and the posterior communicating and posterior cerebral arteries. The extent of the lesion appeared to be closely related to the degree of neurological deficit. 相似文献
133.
MRI gadolinium enhancement of bone marrow: age-related changes in normals and in diffuse neoplastic infiltration 总被引:5,自引:0,他引:5
Objective: To quantify gadolinium-related enhancement in the bone marrow of the spine in normals and in patients with homogeneous diffuse
malignant bone marrow infiltration. Design and patients: The patients consisted of two groups: group 1 comprised 94 healthy adults (18–86 years) without bone marrow disease and group
2 comprised 30 patients with homogeneous diffuse malignant bone marrow infiltration due to myeloma (n=20) or breast carcinoma (n=10). All patients received intravenous gadopentetate dimeglumine (Gd-DTPA), 0.1 mmol/kg body weight. Pre- and postcontrast
signal intensity (SI) on T1-weighted spin-echo (SE) images (TR/TE: 572 ms/15 ms) was measured over a region of interest (ROI)
and the percentage SI increase was calculated. The results were confirmed by bone marrow biopsy (n=20) and clinical parameters (n=10). Dynamic contrast-enhanced studies using a spoiled gradient-recalled-echo (GRE) sequence (TR/TE/α: 68 ms/6 ms 75°) were
performed in 10 controls with normal bone marrow.
Results and conclusion: Contrast material enhancement in healthy persons can vary greatly (range 3–59%, mean 21%, SD 11%). With increasing age there
is a significant decrease in contrast enhancement (Pearson’s correlation, P<0.01). The percentage SI increase in patients with intermediate-grade (biopsy 20–50 vol%) and high-grade (biopsy >50 vol%)
diffuse malignant bone marrow infiltration was significantly higher than in normals (mean 67%, SD 34%, P<0.001). Low-grade (biopsy <20 vol%) diffuse malignant bone marrow infiltration can not be assessed by non-enhanced T1-weighted
SE images or Gd-DTPA application. In conclusion, contrast material enhancement in healthy persons can vary greatly and is
dependent on age, while intermediate-grade and high-grade diffuse malignant bone marrow infiltration can be objectively assessed
with SI measurements. 相似文献
134.
Daniel W. Walsh Vincent B. Ho Michael F. Haggerty 《Journal of magnetic resonance imaging : JMRI》1997,7(2):312-315
Mycotic aneurysms of the abdominal aorta are potentially fatal but uncommon. We report the MRI and MRA features of an abdominal aortic mycotic aneurysm in a patient who presented with nonspecific low back pain. By delineating the saccular nature of the aneurysm and identifying the coexistence of vertebral enhancement, MRI was crucial for the final diagnosis. A potential pitfall of contrast-enhanced MRA is also demonstrated. 相似文献
135.
Temporal Delta Wave and Ischemic Lesions on MRI 总被引:1,自引:1,他引:0
Koji Inui M.D. Hozumi Kawamoto M.D. Masahiko Kawakita M.D. Kazuhisa Wako M.D. Hiromichi Nakashima M.D. Masanori Kamihara M.D. Junichi Nomura M.D. 《Psychiatry and clinical neurosciences》1994,48(4):891-898
Abstract: The present study was designed to determine the clinical significance of a temporal low-voltage irregular delta wave (TLID) on EEG. Among 808 EEG records examined during one year at our hospital, the TLID was commonly detected in patients with clinically diagnosed ischemic brain diseases such as multiple infarction. Subsequently, a relation of the TLID to ischemic lesions on MRI was examined in 50 elderly depressive patients. It was found that there was a close correlation between the occurrence of the TLID and small ischemic lesions on MRI (p<0.001). These results suggest that the TLID is a valuable indicator of minor ischemic changes of the brain. 相似文献
136.
M. Fujioka M.D. K. Okuchi S. Miyamoto T. Sakaki S. Tsunoda S. Iwasaki 《Acta neurochirurgica》1994,131(3-4):265-269
Summary The authors describe a 66-year-old man with progressive gait disturbance caused by bilateral organized chronic subdural haematomas. The characteristics of these lesions on magnetic resonance (MR) images have not yet been clarified. The organized haematoma in our patient exhibited slight hypo-intensity on T 1-weighted MR images and marked hypo-intensity on T 2-weighted MR images obtained at 1.5 T. Preoperative MR imaging may give us useful information about surgical strategy in the case of chronic subdural haematoma with an unusual appearance on computed tomographic (CT) scans. 相似文献
137.
We present a case of spinal cord sarcoidosis which resembled a disseminated intramedullary tumour. The case is unusual because the spinal cord is only rarely affected by sarcoidosis and the patient developed a neurological deficit as the first manifestation of the disease. This condition thus has to be considered in the differential diagnosis of primary intramedullary tumours, or metastatic disease with involvement of the spinal cord. 相似文献
138.
We report a newly developed MR simulation system for intracavitary brachytherapy for cervical cancer and subsequent treatment results. MR simulation was performed on six patients. The spatial relationship of the tumor to the bladder, rectum, bowel, applicators, etc. was depicted well. Doses to the tumor and surrounding normal tissues were read from isodose curves superimposed on the T2-weighted sagittal image. This system promises to be useful in customizing the dose distribution. 相似文献
139.
Simon Vinitski Carlos Gonzalez Feroze Mohamed Tad Iwanaga Robert L. Knobler Kamil Khalili John Mack 《Magnetic resonance in medicine》1997,37(3):457-469
Our aim was to develop an accurate multispectral tissue segmentation method based on 3D feature maps. We utilized proton density (PD), T2-weighted fast spin-echo (FSE), and T1-weighted spin-echo images as inputs for segmentation. Phantom constructs, cadaver brains, an animal brain tumor model and both normal human brains and those from patients with either multiple sclerosis (MS) or primary brain tumors were analyzed with this technique. Initially, misregistration, RF inhomogeneity and image noise problems were addressed. Next, a qualified observer identified samples representing the tissues of interest. Finally, k-nearest neighbor algorithm (k-NN) was utilized to create a stack of color-coded segmented images. The inclusion of T1 based images, as a third input, produced significant improvement in the delineation of tissues. In MS, our 3D technique was found to be far superior to that based on any combination of 2D feature maps (P < 0.001). We identified at least two distinctly different classes of lesions within the same MS plaque, representing different stages of the disease process. Further, we obtained the regional distribution of MS lesion burden and followed its changes over time. Neuropsychological aberrations were the clinical counterpart of the structural changes detected in segmentation. We could also delineate the margins of benign brain tumors. In malignant tumors, up to four abnormal tissues were identified: 1) a solid tumor core, 2) a cystic component, 3) edema in the white matter, and 4) areas of necrosis and hemorrhage. Subsequent neurosurgical exploration confirmed the distribution of tissues as predicted by this analysis. 相似文献
140.
A. Gregory Sorensen Andrew L. Tievsky Leif Ostergaard Robert M. Weisskoff Bruce R. Rosen 《Journal of magnetic resonance imaging : JMRI》1997,7(1):47-55
Contrast agents have greatly expanded the role of MR imaging (MRI) to allow assessment of physiologic, or “functional,” parameters. Although activation mapping generally does not require contrast agents, other forms of functional MRI, including mapping of cerebral hemodynamics (eg, perfusion imaging), are best done with the use of contrast agents. Serial echo planar images are obtained after bolus injection of lanthanide chelates. Application of susceptibility contrast physics and standard tracer kinetic principles permits generation of relative cerebral blood volume maps. Deconvolution of cerebral blood flow and mean transit time parameters is also possible within technical limitations. By using diffusion and perfusion pulse sequences, an imaging correlate to the ischemic penumbra can be identified. Functional MRI perfusion imaging of intraaxial tumors is analogous to positron emission tomography for delineation of metabolic activity, yet may be even more sensitive to neovascularity and possesses improved image quality. Clinical applications include biopsy site selection and postirradiation follow-up. Further improvements in data analysis and map generation techniques may improve diagnostic accuracy and utility. 相似文献