Magnetic resonance imaging of peri-aqueductal lesions

Fourteen lesions in the peri-aqueductal region were evaluated by 0.5T magnetic resonance imaging (MRI) and computed tomography (CT). Fifty normal magnetic resonance studies of the same region were reviewed. The aqueduct of Sylvius is seen in the midline sagittal MRI sections in all normal patients. It is not usually visible in cases of benign stenosis but may be seen in membranous obstruction. Benign stenosis is distinguished from neoplastic obstruction by the lack of increased signal on T2 weighted techniques. Blood within pineal tumours is easily detected and may be differentiated from lipomas, cystic lesions and solid tumours of the brain stem. Arachnoid cysts are also visible in MRI scans.     

侧脑室内脑膜瘤的CT和MRI诊断

目的分析侧脑室内脑膜瘤的CT和MRI表现,以提高诊断准确性。方法回顾性分析8例手术病理证实的侧脑室内脑膜瘤的CT和MRI资料。结果肿瘤呈圆形或分叶状软组织肿块,CT平扫多呈稍高或高密度,MRI多表现为T1WI等信号、T2WI等高信号,除1例因肿瘤坏死致信号和强化不均匀外,余7例肿瘤密度、信号及强化较均匀;周围脑组织可见不同程度水肿。1例肿瘤稍向周围脑组织呈浸润性生长,病理诊断为恶性脑膜瘤。结论侧脑室内脑膜瘤的CT、MRI表现具有一定的特征性,结合临床资料可提高诊断准确性。     

Extraaxiale Hirntumoren

Neuroradiology plays a key role in the diagnosis of patients with brain tumors. Computed tomography (CT) and especially magnetic resonance imaging (MRI) allow accurate anatomic depiction of intracerebral lesions. The implementation of native and contrast studies allows the characterization of the various lesions. This review discusses the imaging aspects with CT and MRI of the most common primary extra-axial brain tumors.     

老年多发性脑梗死诊断中MRI与CT影像检查的应用研究

目的分析在多发性的脑梗死老年患者中行核磁共振(MRI)和CT诊断的价值。方法纳入2018年1-12月多发性脑梗死老年患者50例,全部患者都分别实施核磁共振(MRI)和CT,比较两种方式诊断情况。结果 MRI组阳性检出率为96.00%显著高于CT组检出率78.00%,差异有显著性意义(P<0.05);在50例多发性脑梗死患者中,经病理诊断证实有150个病灶,其中脑室旁有20个、顶叶15个、脑干10个、额叶20个、颞叶10个、基底结节40个、丘脑30个、小脑5个;CT诊断与核磁共振诊断的颞叶、脑室旁对于差异不显著(P>0.05);MRI诊断的顶叶、脑干、额叶、基底结节、丘脑、小脑准确率明显要比CT诊断的高,对比差异有显著性意义(P<0.05)。结论在多发性的脑梗死老年患者中行核磁共振(MRI)效果显著。     

Magnetic resonance imaging of the pediatric thorax: initial experience

Magnetic resonance imaging (MRI) is particularly useful in the pediatric patient. No ionizing radiation is used; there are no complicating side effects; the technique is noninvasive and painless. We reviewed our experience using a 0.15 T. resistive imager for diagnostic MRI of the pediatric thorax. We studied 16 children, aged 8 days to 16 years, with various thoracic diseases. Correlation of the MRI findings with computerized tomography (CT) was obtained in 10 children and with the surgical findings in 8. Spatial resolution was slightly less with MRI than with CT. Medium and large vessels are well seen without contrast medium injection. Tissue characterization with MRI is superior to CT and the normal thymus is well seen. The long scanning time can be a problem in young children but can be overcome using intramuscular sedation. Cardiac gated imaging was successfully tested.     

Magnetic resonance imaging in the staging of renal cell carcinoma

A prospective study has been carried out to examine the role of magnetic resonance imaging (MRI) in the investigation of renal cell carcinoma in 24 patients. In all cases the inferior vena cava (IVC) was well demonstrated with MRI. In 14 out of 15 patients where surgical correlation was available, the MRI and operative staging were in agreement. Magnetic resonance imaging and computed tomographic (CT) staging were in agreement in 16 out of the 17 patients where both were performed. In one case, CT suggested hepatic invasion but this was found not to be present on MRI and at operation. Magnetic resonance imaging also provided substantial additional information in three patients, including two cases where MRI demonstrated a patent IVC that appeared occluded on CT (one of which also had vertebral metastases seen on MRI but missed on CT) and one case where CT failed to demonstrate minimal involvement of the IVC. Magnetic resonance imaging is an accurate means of staging renal cell carcinoma with clear advantages over CT. In no case in this series was inferior vena cavography found to be necessary.     

Magnetic resonance imaging in acute head injury

Using cardiorespiratory monitoring and support equipment compatible with a low field (0.15 T) system, magnetic resonance imaging (MRI) of patients suffering acute head injuries proved to be both feasible and safe. An abnormality was demonstrated by magnetic resonance imaging in 46 of 50 patients examined within 7 days of head injury using T2 weighted (SE2200/80) and T1 weighted (IR2000/600/40) multislice sequences. IN contrast, computed tomography (CT) demonstrated abnormalities in only 31 of the 50 patients. Intracranial extracerebral space-occupying collections of blood were well shown by magnetic resonance imaging which provided especially clear definition in the posterior fossa, subtemporal and subfrontal regions. Magnetic resonance imaging was more sensitive to cerebral abnormalities associated with traumatic unconsciousness and detected parenchymal lesions both in patients in coma and in those who had lost consciousness for only a few minutes. Lesions seen with MRI but not with CT included non-haemorrhagic contusions and abnormalities thought to reflect shearing injuries of white matter and intracerebral vessels. Magnetic resonance imaging is an effective alternative to CT; the additional information it can provide should be valuable in increasing the understanding of the early effects and late consequences of a head injury.     

Imaging findings of neonatal herpes simplex virus type 2 encephalitis

Introduction The CT, MR, and diffusion-weighted initial and follow-up imaging findings in neonatal herpes simplex virus type 2 (HSV-2) encephalitis were assessed. Methods The clinical, laboratory and imaging findings in 12 patients (eight girls and four boys) with proven neonatal HSV-2 encephalitis with follow-up were retrospectively reviewed. Patterns of brain involvement and distribution of lesions were studied and the contribution of diffusion-weighted imaging to the imaging diagnosis of this disease was explored. A total of 24 CT and 22 MRI studies were performed with a mean follow-up time of 38 months. Results Neonatal HSV-2 encephalitis can be multifocal or limited to only the temporal lobes, brainstem, or cerebellum. The deep gray matter structures were involved in 57% of patients, and hemorrhage was seen in more than half of the patients. CT images were normal or showed mild abnormalities in the early stages of the disease. Conventional MR images may be normal in the early stages of the disease. Lesions were initially seen only by diffusion-weighted imaging in 20% of the patients and this modality showed a substantially more extensive disease distribution in an additional 50% of patients. In 40% of patients, watershed distribution ischemic changes were observed in addition to areas of presumed direct herpetic necrosis. Conclusion Neonatal HSV-2 encephalitis has a variable imaging appearance. Diffusion-weighted MRI is an important adjunct in the imaging evaluation of this disease. Watershed distribution ischemia in areas remote from the primary herpetic lesions may be seen.     

Intra-axial brain tumors

Neuroradiology plays a key role in the diagnosis of brain tumors. Computed tomography (CT) and specially magnetic resonance imaging (MRI) allow accurate anatomic depiction of intracerebral lesions. The implementation of native and contrast studies allows the characterization of the various lesions encountered in the majority of cases. In this review the imaging aspects on CT and MRI of the most common primary intra-axial brain tumors will be discussed.     

Intraaxiale Hirntumoren

Neuroradiology plays a key role in the diagnosis of brain tumors. Computed tomography (CT) and specially magnetic resonance imaging (MRI) allow accurate anatomic depiction of intracerebral lesions. The implementation of native and contrast studies allows the characterization of the various lesions encountered in the majority of cases. In this review the imaging aspects on CT and MRI of the most common primary intra-axial brain tumors will be discussed.     

脑部剪裂伤的CT与MRI诊断(附19例报告)

目的 评价CT和MRI对脑部剪裂伤的诊断功效。方法 回顾性分析了19例脑深部剪裂伤的CT和MRI影像表现和特点。结果 CT显示3个病灶，MRI显示了30个损伤灶，19例全部经MRI确诊，CT的敏感性只有MRI的10%。结论 MRI检查尤其是高场强MRI在颅脑剪裂伤的诊断中具有重要意义。比CT检查有显的优越性，随着MRI设备的普及，对颅脑损伤的病人行MRI检查应作为常规。     

Acoustic neuromas: evaluation by magnetic resonance imaging

Proton magnetic resonance imaging (MRI) examinations were performed in six patients with seven acoustic neuromas, and the results were compared with conventional tomography of the internal auditory canals, contrast-enhanced computed tomography (CT), and air CT cisternography. All tumors were identified with MRI. The three largest tumors (greater than 1 cm diameter) looked similar to the tumors seen on CT scans, although the extent of the tumor was better seen with MRI in two cases. The four small (less than or equal to 1 cm diameter) cerebellopontine angle and intracanalicular tumors were well seen with MRI, with appearances corresponding to those seen with air CT cisternography. No side effects were encountered with the MRI examinations. MRI is an accurate, noninvasive alternative to contrast-enhanced CT and air CT cisternography in the diagnosis of acoustic neuromas.     

Magnetic resonance imaging determination of gliomatosis cerebri

Summary Gliomatosis cerebri is a rare condition characterized by diffuse overgrowth of large portions of the brain and spinal cord by glial cells in varying stages of differentiation. The tumor process is primarily an infiltrative, rather than a destructive one. Hence, pre-operative diagnosis by traditional imaging studies, including computed tomography (CT), has been difficult. Magnetic resonance imaging (MRI), with its unique sensitivity for cerebral pathology, is an ideal modality for demonstrating this lesion. We present three cases of gliomatosis cerebri in which high-field MRI clearly delineates the extent of the pathologic process.     

A comparative study of magnetic resonance imaging and computed tomography in the evaluation of migraine

Seventy-four patients with classic migraine were examined by magnetic resonance imaging (MRI) and contrast enhanced head CT scanning. Patients chosen for the study ranged in age from 9 to 39 years with a mean age of 28 years. All had documented symptoms of classic migraine for over two years. Nineteen of the seventy-four patients (26%) had multiple foci of bright signal in the brain on T2 weighted MRI. None of these parenchymal abnormalities were detected on CT scans. Twenty-six patients (35%) had both MRI and CT demonstration of focal or generalized ventricular enlargement or sulcal prominence. These atrophic findings were shown equally well by both modalities. Ten patients (14%) with atrophic changes showed concomitant small bright foci of T2 signal abnormality. An additional migraine patient with homonymous hemianopsia had a large occipital lobe infarct which was seen as a region of bright T2 signal abnormality on MRI. Typical CT characteristics of an acute infarct were demonstrated.     

Isolated oculomotor nerve palsy from minor head trauma

Isolated third cranial nerve palsies in head trauma patients can be the result of direct or indirect damage to the oculomotor nerve. They are usually associated with severe head trauma. We reported a case of isolated oculomotor nerve palsy associated with minor head injury. No initial loss of consciousness was recalled. Computed tomography (CT), magnetic resonance imaging (MRI), and magnetic resonance angiography (MRA) of the brain were normal. Previous reports in the literature were reviewed and the possible mechanism of injury was discussed. Head injuries are commonly seen in sports settings. Our case illustrated that even minor head trauma can cause isolated oculomotor nerve palsy in the absence of abnormal brain imaging findings.     

Magnetic resonance imaging of the abnormal female pelvis

Twenty-three women with 27 instances of pelvic pathology were evaluated by magnetic resonance imaging (MRI). Different pulse sequences were used, which varied the dependence of the images on T1 and T2. Sonography was performed on 22 of the 23 patients. Five patients had CT examinations, including the patient who did not have sonography. MRI was also done in four normal volunteers. The spatial resolution of the MRI scans with short TR and TE intervals approached that of CT. There was overlap of MRI signal characteristics between various pathologic entities and also within the same entity (e.g., cystadenomas and endometriomas).     

MRI新技术在脊髓病变中的研究进展

随着MRI新成像序列的研发,目前已在大脑较普遍使用的各种成像技术亦开始应用到脊髓,并成为脊髓MRI一个重要的发展方向。这些技术主要包括:弥散加权成像(DWI)、弥散张量成像(DTI)、波谱成像(MRS)、血氧水平依赖成像(BOLD)及水成像。另外灌注MRI,脊髓及椎管造影等也在很大方面得到进一步发展。本文将对上述序列的研究进展进行综述。     

Early detection of cerebral infarction by31P spectroscopic imaging

Summary Recent advances in magnetic resonance spectroscopy permit noninvasive study of brain metabolism in vivo,³¹P spectroscopic imaging being the method for evaluation of localized phosphorous metabolism. Experimentally, an ischemic-hypoxic brain insult is characterized by depletion of high energy metabolites. These changes are seen immediately after an ischemic insult. We had the opportunity of carrying out³¹P spectroscopic imaging of hyperacute cerebral infarction, while MRI and CT were negative. Cerebral infarction of the middle cerebral artery territory was suggested by³¹P spectroscopic imaging, which was closely consistent with a later-developing region of low density on CT. In cerebral infarction, early detection of the lesion is a useful pointer to the patient's prognosis, making³¹P spectroscopic imaging a potential tool.     

Intracranial metastasis via transplacental (vertical) transmission of maternal small cell lung cancer to fetus: CT and MRI findings

We present the computed tomography (CT) and magnetic resonance imaging (MRI) findings of brain metastases in an unusual case of a premature, 33-week gestational age neonate who was emergently delivered from a mother suspected of having lung cancer according to imaging performed during the third trimester of pregnancy. Owing to the presence of placental metastases noted after delivery, the fetus had initial screening with brain MRI and chest/abdomen CT as well as serial screening imaging studies during the first 5 months of life, all of which were apparently normal. However, serial examinations eventually revealed a cerebellar lesion that significantly improved after chemotherapy but recurred and enlarged within a few months. This lesion was later confirmed to be metastasis by subsequent biopsy and resection. More metastatic lesions were identified in the frontal and temporal lobes on follow-up MRI. In the setting of aggressive maternal malignancy (without known fetal primary malignancy) an intracranial mass can, on the exceedingly rare occasion, result from maternal high-grade malignancy and the neuroradiologist should be alerted to this phenomenon.