Acute disseminated encephalomyelitis and multiple sclerosis: magnetic resonance imaging differentiation

The study was undertaken to compare the MR imaging features of acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS) in a country with a high prevalence of ADEM. Magnetic resonance scans from 33 patients diagnosed clinically with MS (14 patients) or ADEM (19 patients) were reviewed concurrently by two radiologists blinded to the clinical diagnosis. The size, site, morphology and pattern of brain and spinal cord involvement were recorded and the MR imaging diagnosis was compared with the clinical diagnosis. The MR imaging findings matched with the clinical diagnosis in 11 of 14 patients with MS (sensitivity = 78.6%), and with the clinical diagnosis in 15 of 18 patients with ADEM (sensitivity = 78.9%). Three patients had non-specific findings and in a further three patients discordant imaging features were present. One patient with imaging features typical of Balo's concentric sclerosis was diagnosed clinically as suffering from ADEM. In a country with a high prevalence of ADEM, the majority of patients with ADEM and MS can be differentiated on MR imaging.     

急性播散性脑脊髓炎的脑部MRI表现

目的　描述急性播散性脑脊髓炎的脑部MRI表现 ,探讨MRI对该病的诊断价值以及在评价疗效中的作用。方法　符合临床诊断标准的急性播散性脑脊髓炎患者 9例 ,男 8例 ,女 1例 ,年龄 9～ 47岁。 6例发病前有病毒感染或疫苗接种史。全部 9例行头部MRI检查 ,7例行MRI复查。结果　病变多发且分布不对称 ,9例大脑白质受累 ,6例同时累及丘脑 ,4例可见“垂直征” ,病变呈大小不等的片状或点状异常信号 ,6例可见异常对比增强 ,7例复查见异常信号缩小且数目减少。结论急性播散性脑脊髓炎的MRI脑部表现颇具特征性 ,结合病史及单时相病程可作出早期诊断 ,MRI随访是评价疗效的重要手段。MRI显示丘脑受累是鉴别本病与多发性硬化的主要依据。     

MR imaging of brain stem gliomas

Magnetic resonance (MR) and CT examinations of 26 patients with the established or clinically suspected diagnosis of brain stem glioma were reviewed. Eleven tumors were seen on both MR and CT. The entire extent of the abnormality was better outlined on MR, although CT was more advantageous in demonstrating cystic components and calcium deposition. Magnetic resonance and CT depicted focal intratumoral hemorrhage equally. Magnetic resonance was found to be particularly suitable to follow up the progression or regression of the disease. Of particular interest were two patients with evidence of aqueductal obstruction but normal CT appearance of the midbrain; the causative abnormality, believed to be a glioma, was clearly shown by MR imaging. In nine patients the normal appearance was helpful to exclude the possibility of a brain stem glioma. Thus far, results have shown 100% sensitivity (true positive ratio) and specificity (true negative ratio) with MR in the evaluation of brain stem gliomas. It is concluded that MR imaging should be the examination of choice and could be the definitive screening procedure in patients with suspected brain stem glioma.     

CT and MR imaging in neuro-Beh?et disease

Computed tomography and magnetic resonance (MR) studies were done in one case of Behcet disease and showed a focal lesion in the upper brain stem. Early institution of therapy was followed by a complete clinical remission and disappearance of the CT and MR changes. Computed tomography and MR are important modalities for the early detection of Behcet disease when reversibility of the pathological changes is still possible.     

Craniocervical manifestations of neurofibromatosis: MR versus CT studies

Craniocervical manifestations of neurofibromatosis on magnetic resonance (MR) imaging are described in three patients and compared with those on CT. Using MR, intracranial gliomas, schwannomas, and neurofibromas were detected as well as with CT. In addition, a brain stem lesion that was not visualized on CT and a cervical cord lesion that was not suspected clinically were diagnosed with MR. Taking into account the noninvasive nature of MR, we believe that this technique should be the primary imaging modality for screening and follow-up studies in patients with known or suspected neurofibromatosis.     

Magnetization transfer and diffusion tensor MR imaging of acute disseminated encephalomyelitis

BACKGROUND AND PURPOSE: Patients with acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS) have a similar pattern of abnormalities on conventional MR images. We used magnetization transfer and diffusion tensor MR imaging to quantify normal-appearing brain tissue and cervical cord disease in patients with ADEM and to compare findings with those in healthy volunteers and patients with MS. METHODS: Brain dual-echo, T1-weighted magnetization transfer, and diffusion tensor images were obtained in eight patients with ADEM, in 10 patients with MS, and in 10 healthy volunteers. Fast short-tau inversion recovery, T1-weighted, and magnetization transfer cervical cord images were also obtained. We identified lesions on the images and quantified their volumes. We performed histogram analysis of the magnetization transfer ratio (MTR) and average mean histogram analysis of the diffusivity (D) in normal-appearing brain tissue and MTR in the cervical cord. RESULTS: Histogram analysis of normal-appearing brain tissue in patients with MS showed significantly lower MTRs and peak positions and significantly higher D averages compared with those in patients with ADEM. Patients with MS had significantly lower MTRs and D peak heights and significantly higher average D compared with those in healthy volunteers. Between patients with ADEM and control subjects, normal-appearing brain tissue MTR and D histogram metrics did not differ significantly. Cervical cord MTRs did not differ between control subjects and patients with ADEM, whereas the average MTR and histogram peak position was significantly lower in patients with MS than in the other groups. CONCLUSION: Outside the acute phase of disease and as opposed to what happens in MS, the normal-appearing brain tissue and cervical cord in patients with ADEM are spared in the pathologic process.     

Reversibility of CT and MR findings in neuro-Beh?et disease

A woman with neuro-Beh?et disease characterized by recurrent attacks of meningoencephalitis is reported. During an attack of brain stem dysfunction characterized by dysarthria, diplopia, and ataxia, the postcontrast CT showed an enhancing lesion of the upper brain stem. During a subsequent attack characterized by subcortical dementia and amnesia, magnetic resonance (MR) showed abnormal signal intensity in the hypothalamus and upper brain stem. Upon remission of her symptoms, follow-up contrast enhanced CT and MR were entirely normal. Magnetic resonance is especially useful in localizing acute inflammatory lesions in Beh?et disease. This case suggests that abnormal MR and CT findings in neuro-Beh?et disease are potentially reversible and that radiographic improvement parallels clinical improvement.     

儿童急性播散性脑脊髓炎与临床孤立综合征的临床及影像学比较研究

目的探讨急性播散性脑脊髓炎(acute disseminated encephalomyelitis,ADEM)与临床孤立综合征(clini-cally isolated syndrome,CIS)的鉴别诊断要点。资料与方法搜集39例患儿首发中枢神经系统脱髓鞘病变时的临床及影像学资料。其中CIS 18例,包括女13例,男5例;ADEM共21例,其中女8例,男13例。平均随访时间4.2年,最短随访时间为2年。由一名儿科神经医师对CIS及ADEM的临床表现进行了归类总结。由一名资深神经影像学医师对患者ADEM及CIS头颅MRI表现进行分析,内容包括病灶的位置、大小、形态。对计数资料采用Fisher精确检验,对计量资料进行非参数Mann-Whitney U检验。分别应用几种CIS的诊断标准对患儿进行评价,比较分析每种标准诊断的特异性、敏感性、阳性预测值及阴性预测值。结果 39例儿童ADEM与CIS患者中,ADEM发病年龄小,平均约(6.14±3.41)岁;CIS平均发病年龄(10.05±2.87)岁,两者之间差异有统计学意义(P=0.000);ADEM临床表现以发热和运动障碍为主,分别占76%和71%,高于CIS的33%和22%(P=0.011,0.004)。而CIS中视力障碍及脑脊液寡克隆带阳性出现率分别占50%和61%,与ADEM的0%和24%比较,差异具有统计学意义(P=0.000,0.025)。随访中儿童ADEM的改良的Rankin量表评分不如CIS。影像学特征中,与CIS比较,中央白质病变及脑萎缩在ADEM中表现更为明显,分别占100%和38%(P=0.001,0.023);ADEM病灶分布相对对称。CIS的视神经及脊髓病变出现率分别为22%、17%,ADEM未出现此类病变(P=0.037,P=0.089)。"黑洞"在CIS中具有显著特异性,与ADEM比较差异具有统计学意义(P=0.037)。Callen诊断MS的标准敏感性最高,为87%。KIDMUS(2个均满足)MS诊断标准及Callen的鉴别MS与ADEM标准特异性均较高,分别为92%和90%。KID-MUS敏感性最差,为33%。Barkhof的成人MS标准在儿童中敏感性及特异性均较低,分别为22%和57%。结论临床及影像学特征的结合,可以帮助早期诊断与鉴别ADEM与CIS。在诊断CIS时应该用Callen诊断MS标准为主,而鉴别ADEM和CIS时可以用Callen的鉴别标准。     

Progressive multifocal leukoencephalopathy in patients with AIDS: appearance on MR images

Progressive multifocal leukoencephalopathy (PML) is an uncommon demyelinating disease that occurs in immunocompromised patients. The authors evaluated magnetic resonance (MR) images of 10 patients with pathologically proved PML and clinically diagnosed acquired immunodeficiency syndrome (AIDS) to determine the MR characteristics of this disorder. All patients had asymmetric cerebral involvement. Lesions were distributed throughout the brain, including the brain stem and basal ganglia. White matter was affected in all 10 patients; gray matter was also involved in five. In one patient the lesion enlarged and crossed the corpus callosum and contained focal hemorrhage. The authors conclude that, contrary to reported findings on computed tomographic scans, PML in patients with AIDS has a variable appearance on MR images and has many characteristics that differ from those previously thought to be typical on imaging studies.     

肝豆状核变性的脑MRI诊断

作者对８例临床确诊的肝豆状核变性脑ＭＲＩ进行了分析。结果表明异常信号分布广泛并且对称出现，以基底节、丘脑和脑干为著。病变形态及信号较具特点。Ｔ２加权像高信号较常见，其信号基础为继发于铜沉积的水肿、胶质增生或空腔，Ｔ２加权像低信号为本病特征性改变，系铜的顺磁性作用造成Ｔ２弛像时间缩短所致，它的出现对病程判断很有帮助。对ＭＲＩ与临床表现的关系也作了初步探讨。作者认为ＭＲＩ对肝豆状核变性的早期诊断、疗效     

Rhinocerebral mucormycosis: MR manifestations

Magnetic resonance (MR) examinations of three patients with rhinocerebral mucormycosis are reviewed. The clinical course is outlined and the MR characteristics are analyzed in light of the known pathology. The major MR findings include sinus and orbital disease followed by deep facial extension. Involvement of basal portions of the hemispheres, brain stem, and hypothalamus occurred rapidly following ipsilateral facial or orbital invasion in all three cases. Regions of intracerebral inflammation were hyperintense compared with normal parenchyma on T2-weighted and proton density-weighted images. Septic cavernous sinus and internal carotid artery thrombosis was diagnosed by MR in one case. Magnetic resonance demonstrated partial resolution of intracerebral abnormalities that accompanied clinical improvement in the one surviving patient.     

Clinical,neurodiagnostic, and MR findings in children with spinal and brain stem multiple sclerosis.

PURPOSETo describe the clinical, neurodiagnostic, and MR findings in seven children with brain stem and spinal multiple sclerosis.METHODSSpinal or brain stem multiple sclerosis was diagnosed in seven children between 1986 and 1992. All patients had neurologic and MR examinations as well as neurodiagnostic testing, including spinal fluid analysis and brain stem and auditory evoked potentials.RESULTSThree children had clinical findings and masslike lesions in the brain stem (two) or spinal cord (one) suggestive of neoplasm, which prompted biopsy (two) or radiation therapy (one). Five of six patients with spinal involvement had cord swelling with increased signal on T2-weighted images over at least three cord segments, and two children had essentially holocord involvement. Three children had normal cranial MR at presentation.CONCLUSIONSMultiple sclerosis involvement of the brain stem and spinal cord may be associated with extensive swelling and MR signal changes suggestive of neoplasm without typical cerebral white matter abnormalities. Serial clinical and neuroimaging examinations may be necessary to make a definitive diagnosis of multiple sclerosis in children.     

Achilles tendon injuries: the role of MR imaging

Eight magnetic resonance (MR) examinations were performed in seven patients with Achilles tendon injuries and correlated with physical examination and surgical and clinical follow-up. The MR examinations depicted the Achilles tendon in excellent detail and Achilles tendon abnormalities with greater accuracy than physical examination. Of five tendons shown to be at least partially torn on MR, palpable tendinous defects were found in only one, and plantarflexion weakness was found in four. The MR and surgical findings precisely correlated in one case. Magnetic resonance proved valuable in the evaluation of clinically equivocal Achilles tendon tears and may ultimately play a greater role as a research tool in the determination of optimal forms of therapy for specific Achilles tendon injuries.     

Subacute sclerosing panencephalitis: evaluation with CT and MR.

PURPOSETo evaluate the progression of CT and MR changes of the brain in subacute sclerosing panencephalitis (SSPE) as a basis for assessing the effects of different types of therapy.METHODSFifty-two patients with SSPE were examined, 44 with MR imaging and 42 with CT of the brain on one or more occasions. A total of 92 MR and 67 CT studies were performed.RESULTSCorrelation between the clinical status and the MR findings in admission was poor. Of 20 patients with clinically advanced disease, only 8 had marked MR abnormalities; 6 had normal or almost normal findings on MR examinations. Two of 4 patients with clinically mild disease had advanced MR changes. The progression of the MR findings appeared to follow a constant pattern. The earliest pathologic finding was focal, high-T2-intensity white matter changes; later atrophic changes followed. The atrophy lagged behind the white matter changes and was thus mild when white matter changes were moderate or severe. In the most advanced stage, when the patient was in a neurovegetative state, an almost total loss of white matter had usually taken place. At this stage, the corpus callosum was also thin. Basal ganglia changes, usually involving the putamina, were seen in one third of patients and cortical gray matter changes were seen in one fourth of patients examined with MR imaging. In 2 of 20 patients, MR changes regressed in parallel with clinical improvement following therapy, but in 5 patients clinical improvement was accompanied by progression of MR changes.CONCLUSIONThe progress of MR abnormalities seen in patients with SSPE seems to follow a constant pattern, but the severity of MR changes does not always correlate well with the clinical findings. Caution must therefore be used when evaluating the effects of therapy.     

Delayed MR imaging changes in acute disseminated encephalomyelitis.

BACKGROUND AND PURPOSE: White matter lesions on MR images obtained from patients with acute disseminated encephalomyelitis (ADEM) have been reported to appear shortly after symptom onset, and their resolution has been claimed to parallel recovery. To elucidate the temporal evolution of these lesions and to associate the changes on MR images to the patients' clinical condition, we performed serial MR imaging on patients with ADEM. METHODS: Several consecutive T2-weighted and fluid-attenuated inversion recovery scans were obtained from four previously healthy adult patients with ADEM within the first days after the onset of symptoms and again during the recovery period. MR imaging was done first on a weekly to biweekly basis and later at 1- to 2-month intervals for up to 8 months. RESULTS: MR scans of three of these patients did not show any specific abnormalities until several weeks after the onset of the disease. As the lesions later appeared, their number increased during the recovery period. CONCLUSION: MR imaging performed during the first days after the onset of the disease may not reveal any pathologic findings. The appearance of the ADEM-associated MR imaging changes may be associated with recovery rather than decline. It remains to be studied whether the new MR imaging techniques reveal the lesions associated with ADEM faster than the conventional T2-weighted imaging.     

Chiari I malformations: clinical and radiologic reappraisal.

Clinical findings and magnetic resonance (MR) images in 68 patients with Chiari I malformations were retrospectively analyzed to identify those radiologic features that correlated best with clinical symptoms. A statistically significant (P = .03) female predominance of the malformation was observed, with a female: male ratio of approximately 3:2. Associated skeletal anomalies were seen in 24% of patients. Syringomyelia was detected in 40% of patients, most commonly between the C-4 and C-6 levels. Of the 25 patients who presented with spinal symptoms, 23 (92%) proved to have a syrinx at MR imaging. When the syrinx extended into the medulla (n = 3), however, brain stem symptoms predominated. Patients with objective brain stem or cerebellar signs had the largest mean tonsillar herniations. Patients with tonsillar herniations greater than 12 mm were invariably symptomatic, but approximately 30% of patients with tonsils herniating 5-10 mm below the foramen magnum were asymptomatic at MR imaging. "Incidental" Chiari I malformations are thus much more common than previously recognized, and careful clinical assessment remains the cornerstone for proper diagnosis and management.     

An exploratory study of ferumoxtran-10 nanoparticles as a blood-brain barrier imaging agent targeting phagocytic cells in CNS inflammatory lesions

BACKGROUND AND PURPOSE: Iron oxide-based contrast agents have been investigated as more specific MR imaging agents for central nervous system (CNS) inflammation. Ferumoxtran-10 is a virus-size nanoparticle, taken up by reactive cells, that allows visualization of the phagocytic components of CNS lesions. Ferumoxtran-10 was compared with standard gadolinium-enhanced MR images in this exploratory trial to assess its potential in evaluation of CNS lesions with inflammatory aspects, including lymphoma, multiple sclerosis (MS), acute disseminated encephalomyelitis (ADEM), and vascular lesions. METHODS: Twenty-three patients with different types of intracranial "inflammatory" lesions underwent standard brain MR with and without gadolinium, followed an average of 10 days later by a ferumoxtran-10 scan. Patients were imaged 24 hours after infusion of 2.6 mg/kg ferumoxtran-10. All MR images were evaluated subjectively by 4 investigators for a difference in enhancement patterns, which could be useful in differential diagnoses. RESULTS: In 5 cases, (one ADEM, 2 stroke, one cavernous venous vascular malformation, one primary central nervous lymphoma) the ferumoxtran-10 scan showed higher signal intensity, larger area of enhancement, or new enhancing areas compared with gadolinium. Most MS patients showed less enhancement with ferumoxtran-10 than with gadolinium. CONCLUSION: Ferumoxtran-10 showed different enhancement patterns in a variety of CNS lesions with inflammatory components in comparison to gadolinium. The impact of timing and therapy need further evaluation to better assess ferumoxtran-10 in addition to gadolinium as contrast agents for use in diagnosis and monitoring therapy in patients with CNS inflammatory lesions.     

Differences in water diffusion and lactate production in two different types of postinfectious encephalopathy

We compared two different types of postinfectious encephalopathy using magnetic resonance imaging (MRI), including diffusion-weighted images and MR spectroscopy. Acute disseminated encephalomyelitis (ADEM) and acute necrotizing encephalopathy (ANE) showed different distribution of abnormal intensity areas and different diffusion of water measured by diffusion-weighted imaging (DWI). Proton MR spectroscopy (MRS) showed lactate production in both cases, which returned to a normal range; the rate of increased lactate production was much lower in the ANE case. Water diffusion showed a difference in pathophysiological background between the two encephalopathies, but the lactate elevation observed by proton MRS did not correlate with clinical severity.     

Brain fiber tracking with clinically feasible diffusion-tensor MR imaging: initial experience

Two technical challenges must be overcome before brain fiber tracking with diffusion-tensor magnetic resonance (MR) imaging can be applied to clinical practice: Imaging time must be shortened, and image distortion must be minimized. Single-shot echo-planar MR imaging with parallel imaging technique enabled both objectives to be accomplished. Twenty-three consecutive patients with brain tumors underwent MR imaging with a 1.5-T whole-body MR system. Fiber tracts on the lesion side in the brain had varying degrees of displacement or disruption as a result of the tumor. Tract disruption resulted from direct tumor involvement, compression on the tract, and vasogenic edema surrounding the tumor. This diffusion-tensor MR imaging method with the parallel imaging technique allows clinically feasible brain fiber tracking.     

Wilson disease of the brain: MR imaging

Twenty-three patients with biochemically proved Wilson disease underwent magnetic resonance (MR) imaging of the brain. Positive findings, believed secondary to this condition, were found in 15 subjects. Findings varied among patients, but there were striking similarities between certain groups of patients. Areas of abnormal signal were seen in the lenticular, thalamic, caudate, and dentate nuclei, as well as in the brain stem; in these areas, the abnormalities were bilaterally symmetric. A smaller number of patients had asymmetric focal white-matter lesions. Correlation of the MR findings with clinical symptoms was generally good. Repeat imaging was performed on five patients at intervals ranging from 4 to 8 months; none showed significant interval change.