Magnetic resonance imaging in tuberous sclerosis

Twenty-five patients with tuberous sclerosis were studied with magnetic resonance imaging (MRI), and these findings were compared with those of computed cranial tomography (CCT) and with the clinical severity of the disease. Multiple high-signal MRI lesions involving the cerebral cortex are characteristic of tuberous sclerosis and probably correspond to the hamartomas and gliotic areas seen pathologically. These cortical lesions were only occasionally seen with CCT. The periventricular calcific lesions characteristic of tuberous sclerosis are better visualized with CCT than with MRI, but the larger periventricular calcifications produce low-signal MRI abnormalities. Seven patients had high-signal MRI lesions of the cerebellum; small calcific cerebellar lesions were also noted with CCT in three patients. As in earlier studies, no clear correlation was seen between the number of abnormalities visible with CCT and the clinical severity of the disease. By contrast, the more severely affected patients tend to have a higher number of cerebral cortical lesions detected with MRI. Thus, MRI may be useful in predicting the eventual clinical severity of younger children with newly diagnosed tuberous sclerosis.     

Magnetic resonance imaging of intracranial lesions of tuberous sclerosis

Six patients with tuberous sclerosis were evaluated with computed cranial tomography (CCT) and magnetic resonance imaging (MRI). The results were assessed in comparison with the clinical severity of the disease. The brain lesions were shown by MRI as low-signal areas on IR images (T1 weighted sequences) and high-signal areas on SE images (T2 weighted sequences) Three patients, who had severe psychomotor retardation (DQ less than 70) and intractable epileptic seizures following infantile spasms, had many cortical and subcortical lesions. In the other three patients, intelligence was normal or slightly retarded (DQ or IQ greater than 70) and epileptic seizures were well controlled, and small subependymal lesions were observed. Cortical lesions were rare. These results indicate that MRI can detect more precisely intracranial lesions in tuberous sclerosis.     

Magnetic resonance imaging in Bourneville's disease: relation to the EEG

Six children affected by tuberous sclerosis and severe multifocal epilepsy were studied by MRI. In all cases, MRI disclosed multiple cortical lesions and the relationship between these lesions and the EEG localization of epileptogenic foci has been studied. In all cases, a relationship between the localization of persistent EEG foci and the site of the major MRI lesions was found. The presence of frontal cortical tubers, mainly localized in the parasagittal region, was related to more intractable seizures.     

伴有癫痫发作的结节性硬化症患者的脑电图特点

目的分析伴有癫痫发作的结节性硬化症(TSC)患者的脑电图特点。方法总结101例有痫性发作的TSC患者的临床资料,对其发作间期及发作期脑电图进行分析。结果癫痫的发病年龄从10d～28岁不等,3岁以内发病者68人(67%)。101例患者均行24h视频脑电图监测,3例脑电图正常,98例脑电图异常,其中3例存在高幅失律,23例为慢波背景活动,72例背景活动正常或接近正常,但其中11例患者脑电图可见较多慢活动。在有痉挛发作的13例患者中,3例脑电图背景为高幅失律,7例为慢波背景活动。发作间期显示痫样波在双侧均明显者35例,一侧痫样波明显者63例,主要集中在前头部。48例患者监测到发作,监测到的发作最常见为部分性发作(27例),26例可以明确起源,主要集中在额颞叶。结论大多数TSC患者脑电图异常,可见痫样波发放,54%TSC患者通过视频脑电图可以明确痫样波起源,主要在额颞叶,左右两侧无明显差异。     

Magnetic source imaging and reactivity to rhythmical stimulation in tuberous sclerosis

The present study combined functional magnetoencephalography (MEG) and anatomical magnetic resonance imaging (MRI) information in three patients affected by tuberous sclerosis and partial epilepsy. MEG recordings were performed during both spontaneous and visual evoked activity. The former showed a large variety of complexes whose spatial and temporal distribution suggested different neuronal populations acting simultaneously in the same focal district. When these data were integrated with MRI images (magnetic source imaging, MSI) there was agreement in the definition of tubers and extension of the epileptogenic area. Furthermore, cortical reactivity to rhythmical stimulation was studied with trains of visual stimuli according to a recently proposed frequency responsiveness procedure (FRP). As compared to normal controls, a large 6 Hz activity was observed during the pause after a non-resonant stimulation. This altered resonance property may indicate a disturbed primary sensory processing notwithstanding a preserved associated processing. These results show that neuronal malfunctioning in tuberous sclerosis complex patients may not be restricted to the area of cortical tubers, but can also affect functionally correlated regions.     

Magnetic resonance imaging in multiple sclerosis

Magnetic resonance imaging (MRI) has played a central role in the clinical management and scientific investigation of multiple sclerosis (MS) and has become the most important ancillary tool for diagnosing and monitoring the disease. Conventional MRI techniques are used to assess overt lesions and atrophy in the central nervous system and include spin-echo T2-weighted, pre- and post-gadolinium-enhanced spin-echo T1-weighted, and fluid-attenuated inversion-recovery images. Advanced MRI techniques such as diffusion-weighted imaging, magnetization transfer imaging, magnetic resonance spectroscopy, and functional MRI have increased our understanding of the pathogenesis of MS. The role of these newer techniques in clinical practice remains under investigation. In this review, we will focus on the role of MRI in the diagnosis and management of MS. We will also review how advanced MRI techniques contribute to our understanding of MS.     

Multimodality imaging for improved detection of epileptogenic foci in tuberous sclerosis complex

OBJECTIVE: Using interictal alpha-[11C]methyl-l-tryptophan ([11C]AMT) PET scan, the authors have undertaken a quantitative analysis of all tubers visible on MRI or 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) PET, to determine the relationship between [11C]AMT uptake and epileptic activity on EEG. BACKGROUND: Tuberous sclerosis complex (TSC) is an autosomal dominant disorder, often associated with cortical tubers and intractable epilepsy. The authors have shown previously that [11C]AMT PET scans show high tracer uptake in some epileptogenic tubers and low uptake in the remaining tubers. METHODS: Eighteen children, age 7 months to 16 years, were studied. Patients underwent video-EEG monitoring, PET scans of [11C]AMT and [18F]FDG, and T2-weighted or fluid-attenuated inversion recovery (FLAIR) MRI. [11C]AMT uptake values were measured in 258 cortical tubers delineated with coregistered MRI or [18F]FDG scans. Uptake ratios were calculated between the [11C]AMT uptake in tubers and those for normal cortex (tuber/normal cortex). Using the region of epileptiform activity, the authors performed receiver operator characteristics (ROC) analysis and determined the optimal uptake ratio for detecting presumed epileptogenic tubers. RESULTS: Tuber uptake ratios ranged from 0.6 to 2.0. Tuber uptake ratios in the epileptic lobes were higher than those in the nonepileptic lobes (p < 0.0001). All 15 patients with focal seizure activity showed one or more lesions with uptake ratio above 0.98 in the epileptic lobe. ROC analysis showed that a tuber uptake ratio of 0.98 resulted in a specificity of 0.91. CONCLUSIONS: Cortical tubers with [11C]AMT uptake greater than or equal to normal cortex are significantly related to epileptiform activity in that lobe. Together, interictal [11C]AMT PET and FLAIR MRI improve the detection of potentially epileptogenic tubers in patients with TSC being evaluated for epilepsy surgery.     

Magnetic resonance spectroscopy of tubers in patients with tuberous sclerosis

OBJECTIVE: The histological features of cortical tubers in patients with tuberous sclerosis (TS) were studied by the proton magnetic resonance spectroscopy (MRS). MATERIAL AND METHODS: The subjects were 4 children, mean age of 10 years, with clear evidence of tubers on MRI and SPECT. Four age-matched control children served as control subjects. Spectra were acquired over the tuber using short TE. RESULTS: The myoinositol/creatine ratios in the tubers of TS patients were significantly increased compared with those of the control subjects (P < 0.02). The NAA/creatine ratios in the tubers of patients were significantly decreased (P < 0.02). CONCLUSIONS: The decrease of NAA/creatine ratios in the tubers of patients was considered to reflect a reduction of cranial neurons. The increase of myoinositol/creatine ratios in the tubers was thought to reflect an increase of glial cells. Proton MRS might play a role in estimation of histological changes in the neurological diseases.     

Magnetic resonance imaging in amyotrophic lateral sclerosis

Magnetic resonance imaging (MRI) was used in 5 patients with clinically definite amyotrophic lateral sclerosis to determine the frequency of central white matter abnormalities. Two patients had symmetrical areas of increased signal intensity seen on MRI extending from the cortex, through the corona radiata, posterior limb of the internal capsule, and cerebral peduncles into the pons. These MRI abnormalities presumably relate to the pathological changes observed by others in the central white matter of patients with amyotrophic lateral sclerosis.     

Magnetic resonance imaging in amyotrophic lateral sclerosis

OBJECTIVE: We aimed to investigate the importance of magnetic resonance imaging for the diagnostic process of the upper motor neuron involvement. MATERIAL AND METHODS: Fifteen patients (Group 1) who were diagnosed with amyotrophic lateral sclerosis in the neurology department of the Sisli Etfal Hospital and 20 controls (Group 2) entered the study. Magnetic resonance imaging examinations were performed in the radiology clinic of the same hospital. T2 and proton density weighted axial images were obtained. These images were evaluated by two blind radiologists. The radiologists looked for two signs: the presence of a low signal intensity at the precentral cortex and the presence of symmetrical rounded foci of high signal intensity within the internal capsule on both T2 and proton density weighted images. RESULTS: For the first sign there was no statistically significant difference between the two groups but for the latter one there was a statistically significant difference. CONCLUSION: We think that the presence of the latter sign may make it possible for the radiologists to help the clinicians further in this difficult and confusing diagnosis.     

Magnetic resonance imaging in multiple sclerosis]

Useful characteristics of MRI finding of multiple sclerosis (MS) include the distribution of lesions such as a strictly periventricular, infratentorial, or juxtacortical location, involvement of the corpus callosum and the presence of ovoid lesions with long axis directed to lateral ventricles. Our MRI-diagnostic criteria improved the sensitivity and specificity and is clinically useful. New sequences, such as fast spin echo, turbo spin echo or fluid attenuated inversion recovery have improved the detection of lesions. The presence of contrast enhancement in some but not all lesions--that is, evidence of both old and new lesions--provides additional diagnostic support. Enhanced lesions with more than 1 cm diameter often become ring-shaped. Strong correlations were found between the number and volume of enhancing lesions with changes of T 2 and magnetization transfer (MT) lesion loads in patients with secondary progressive MS. The degree of hypointensity of so called black holes on moderately T1-weighted spin echo images correlates with loss of magnetisation transfer, a marker of destruction of matrix and axon, and shows correlation with disability. One of spectroscopic indices of axonal loss is N-acetylaspartate. Atrophy is a process closely linked with the progressive phase of MS and worsening disability. Detection of the reduction in cord cross-sectional area or spinal cord atrophy over time makes an important contribution to the evaluation of therapeutic efficacy, especially in primary progressive disease.     

Regional cerebral blood flow in relation to MRI and EEG findings in tuberous sclerosis.

To identify the focus of paroxysmal neuronal activity causing epilepsy in tuberous sclerosis (TS), the regional cerebral blood flow (r-CBF) in 19 patients with TS was assessed using single-photon emission computed tomography (SPECT) with I-123 iodoamphetamine (IMP), in correlation with serial interictal EEGs and organic changes observed on magnetic resonance imaging (MRI). There was a general irregularity of cortical IMP uptake and retention in TS, and two-thirds of the cerebral regions exhibiting high intensity in T2-weighted MRI images (cortical tubers) showed a decrease in r-CBF. In addition to in tubers, decreased r-CBF was observed in regions in which MRI was considered to indicate destruction of the normal cortex, atrophy or vascular abnormalities, although these areas did not consistently show epileptic changes in serial EEGs. Among the cortical regions which consistently showed epileptic foci in serial EEGs, none showed abnormal r-CBF without lesions on MRI. We conclude that IMP-SPECT is useful for visualizing the epileptogenic laterality in cases with bilateral MRI lesions and EEG epileptic changes, and to differentiate epileptogenic foci from electrophysiological propagated areas. However, regarding the severity of epilepsy, the MRI findings showed a better correlation than the IMP-SPECT findings did.     

Dense array EEG estimated the epileptic focus in a patient with epilepsy secondary to tuberous sclerosis complex

Purpose

Tuberous sclerosis complex (TSC) is a leading cause of epilepsy, with seizures affecting almost 80–90% of children. We used the concordance between magnetic resonance imaging (MRI) and dense array electroencephalography (dEEG) findings to detect epileptic focus in a patient with TSC.

Lateralization of epileptic foci by magnetic resonance imaging in temporal lobe epilepsy.

A retrospective single-blind study was carried out to assess the reliability of magnetic resonance imaging (MRI) for determining lateralization of the electrographic focus in 45 patients with intractable temporal lobe epilepsy. With strictly defined MRI diagnostic criteria, the electroencephalographic (EEG) focus was correctly lateralized in 86% of patients. Excluding patients with structural lesions, the criteria provided for correct lateralization of the epileptogenic focus in 78% and false lateralization in 5%. Hippocampal atrophy on T1-weighted images and increased signal intensity from mesial structures on T2-weighted scans were highly reliable for lateralization. Postoperative outcome did not differ between the patients with normal and those with abnormal findings on MRI, but the group sample was inadequate to assess the issue of surgical outcome. These findings suggest that with appropriate techniques and strictly defined diagnostic criteria, MRI can provide reliable seizure lateralization in patients with intractable temporal lobe epilepsy.     

Magnetic source imaging localizes epileptogenic zone in children with tuberous sclerosis complex

The authors assessed whether magnetoencephalography/magnetic source imaging (MEG/MSI) identified epileptogenic zones in patients with tuberous sclerosis complex (TSC). In six TSC children with focal seizures, ictal video-EEG predicted the region of resection with 56% sensitivity, 80% specificity, and 77% accuracy (p = 0.02), whereas interictal MEG/MSI fared better (100%, 94%, and 95%, respectively; p < 0.0001). Interictal MEG/MSI seems to identify epileptogenic zones more accurately in children with TSC and focal intractable epilepsy.     

Magnetic resonance imaging and cognitive functioning in multiple sclerosis

Summary The relationship between cognitive impairment in multiple sclerosis and brain lesions seen on magnetic resonance imaging (MRI) was studied. Three groups of 11 patients with multiple sclerosis, matched for the variables of disability, duration of illness, age and sex, were included. On the basis of neuropsychological testing, the groups were seen to differ in their level of cognitive impairment. The first group showed no cognitive impairment, the second group a moderate, and the third group a serious cognitive impairment. These differences between the groups were reflected by MRI, which revealed more abnormalities in the groups with cognitive impairment compared with the group with normal cognitive function. However, by MRI it was not possible to distinguish between the groups with moderate and that with serious cognitive impairment.     

Magnetic resonance imaging in tonic spasms of multiple sclerosis

Two cases of unilateral tonic spasm are described in which high signal lesions typical of demyelination were identified on magnetic resonance imaging in the contralateral cerebral peduncle. Both cases exhibited subtle upper motoneuron signs on the side of the tonic spasms that were exacerbated immediately following an attack. In one case, functional impairment of contralateral corticospinal pathways was demonstrated by delayed central motor conduction. These cases support the view that tonic spasms in multiple sclerosis are due to lesions within the corticospinal tract.