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Li Min Li

Publications and source records attributed to Li Min Li.

At least 19 recordsLinked to original sources
PubMed2006

Longitudinal analysis of gray and white matter loss in patients with systemic lupus erythematosus.

Cerebral atrophy has been described to occur in systemic lupus erythematosus (SLE) with variable frequency. The aim of this study was to determine white and gray matter abnormalities in brain magnetic resonance imaging (MRI) of patients with SLE and to determine if these abnormalities progress over a one-year period. Seventy-five patients with SLE and 44 healthy age and sex-matched controls were enrolled in this study. T1-weighted volumetric images were used for voxel based morphometry (VBM) analyses. SLE patients exhibited a significant reduction in white matter and gray matter volume compared to controls (p=0.001). Follow-up images, after an average interval of 19 months, revealed a progressive white matter and gray matter atrophy (p=0.001). Reduced white and gray matter volume was associated with disease duration and the presence of antiphospholipid antibodies. Patients with severe cognitive impairment had a more pronounced white and gray matter reduction than patients with moderate cognitive impairment. Total corticosteroid dose was associated with gray matter reduction and not with white matter loss in SLE patients. We concluded that brain tissue loss associated with SLE is significant and progresses over a relatively short period of time. Disease duration, the presence of antiphospholipid antibodies and cognitive impairment were associated with white and gray matter loss. Corticosteroid was associated only with gray matter atrophy.

Adolescent↗
PubMed2006

Microstructural white matter abnormalities in nodular heterotopia with overlying polymicrogyria.

Nodular heterotopia (NH) with overlying polymicrogyria can result in medically uncontrolled seizures. Most patients also exhibit deficits of function related to the location of the abnormal cortex. However, functional imaging studies show that the abnormal cortex can retain some function, making surgical planning difficult. It is not known if the connectivity of the abnormal cortex is normal. In this article, we performed an evaluation of molecular diffusion within the white matter in a patient with refractory epilepsy due to NH with overlying polymicrogyria. We observed that the white matter underlying the polymicrogyric area shows signs of microstructural abnormalities. This result suggests that the deficit of function from polymicrogyria result from both the structurally abnormal cortex and from its impaired connectivity.

Adult↗
PubMed2006

Gray matter atrophy associated with duration of temporal lobe epilepsy.

Hippocampal sclerosis is the most common abnormality associated with medial temporal lobe epilepsy (MTLE). Converging evidence supports that hippocampal sclerosis progresses with time. However, it is unclear whether extrahippocampal atrophy in patients with MTLE, similarly to hippocampal sclerosis, is an unremitting progressive process. In this article, we investigate the relationship between duration of epilepsy and gray matter concentration reduction in patients with MTLE within and outside the hippocampus. We employed a voxel-based morphometry study of MRI of the entire brain of 36 patients with drug refractory MTLE and 49 neurologically healthy age-matched controls. We performed a voxel-based parametric and nonparametric investigation of the association between gray matter concentration, age and duration of epilepsy. We complemented the investigation by extracting the gray matter concentration of regions of interest (ROIs) within the limbic system, and we investigated the association between the gray matter concentration on the ROIs and duration of epilepsy. Patients with MTLE exhibited gray matter concentration reduction that is negatively correlated with the duration of epilepsy within the ipsilateral hippocampus, temporal lobes as well as extratemporal limbic structures that are closely connected with the hippocampus. In conclusion, longer duration of refractory epilepsy was associated with a more intense hippocampal and extrahippocampal atrophy in patients with MTLE. The mechanism of progressive neuronal damage in MTLE may be related to active seizure activity within a limbic network, and early seizure control may prevent further brain atrophy in patients with refractory MTLE.

Adolescent↗
PubMed2006

Voxel-based morphometry in patients with idiopathic generalized epilepsies.

Idiopathic generalized epilepsies (IGE) are a group of frequent age-related epilepsy syndromes. IGE are clinically characterized by generalized tonic-clonic, myoclonic and absence seizures. According to predominant seizure type and age of onset, IGE are divided in subsyndromes: childhood absence and juvenile absence epilepsy (AE), juvenile myoclonic epilepsy (JME) and generalized tonic-clonic seizures on awakening (GTCS). The limits between these subsyndromes are not well defined, supporting the existence of only one major syndrome. Visual assessment of routine magnetic resonance imaging (MRI) in patients with IGE is normal. MRI voxel-based morphometry (VBM) uses automatically segmented gray and white matter for comparisons, eliminating the investigator bias. We used VBM to study 120 individuals (47 controls, 44 with JME, 24 with AE and 15 with GTCS) to investigate the presence of subtle structural abnormalities in IGE subsyndromes. VBM was performed searching for abnormalities on gray matter concentration (GMC) between patients groups and controls. Compared to controls, JME presented increased GMC in frontobasal region and AE showed increased GMC in the superior mesiofrontal region. The GTCS group did not differ from controls. There were no areas of reduced GMC with the statistical level selected. Region of interest analysis showed increased GMC in the anterior portion of the thalamus in patients with absence seizures. Our results support subtle GMC abnormalities in patients with JME and AE when compared to controls. These findings suggest the existence of different patterns of cortical abnormalities in IGE subsyndromes.

Adolescent↗
PubMed2006

MRI volumetry shows increased anterior thalamic volumes in patients with absence seizures.

The interaction between thalamus and cortex appears to be critical to the pathophysiology of idiopathic generalized epilepsies (IGEs). The objective of this study was to investigate thalamic volumes of a group of patients with IGEs using high-resolution MRI. Thalamic segmentation was performed by the same rater, who was unaware of the diagnosis. Thalamic volumes were divided into anterior half and posterior half. One hundred forty-seven patients were scanned (71 with juvenile myoclonic epilepsy, 49 with generalized tonic-clonic seizures only, and 27 with absence epilepsy). Subgroup analyses with corrections for multiple comparisons showed that, when compared with those of controls, anterior thalamic volumes were increased in patients with absence epilepsy and juvenile myoclonic epilepsy with absence seizures, but not in patients with generalized tonic-clonic seizures only and juvenile myoclonic epilepsy without absence seizures. Our results demonstrated that the anterior thalamus is structurally different in patients with IGEs and absence seizures as compared with patients with IGEs without absence seizures.

Adult↗
PubMed2006

Voxel-based morphometry reveals excess gray matter concentration in patients with focal cortical dysplasia.

PURPOSE: Many patients with focal cortical dysplasia (FCD) continue to have seizures after surgical treatment. The usual explanation for the poor surgical outcome is the presence of residual dysplastic tissue missed by the preoperative neuroimaging investigation and therefore not resected during surgery. We apply a voxel-based morphometry (VBM) analysis to the magnetic resonance imaging (MRI) scans from patients with epilepsy and visually detected FCD to investigate whether (a) VBM is able to detect gray-matter concentration (GMC) abnormalities in patients with FCD, and (b) whether the extent of GMC abnormalities in the brain of these patients differs from the regions observed by using visual inspection. METHODS: We studied 11 patients with visually detected FCD (eight of them with histologic confirmation of FCD). The GMC from each one of these patients was compared with the mean GMC from a control group of 96 normal healthy subjects by using an optimized VBM protocol. RESULTS: Ten of 11 patients showed statistically significant GMC excess, and among patients with GMC excess, only one showed GMC excess that was not exactly correspondent to the visually detected FCD. Seven patients exhibited excess in GMC extending beyond the area of visually detected FCD. CONCLUSIONS: This preliminary neuroimaging study suggests that (a) VBM can detect GMC excess in patients with FCD, and (b) GMC excess in these patients can extend to brain areas not visually defined as abnormal. Abnormal areas detected by VBM can possibly correspond to mild malformations of cortical development, supporting the notion that the surgical refractoriness observed in patients with FCD can be due to the incomplete resection of the dysplastic tissue.

Adolescent↗
PubMed2006

Amygdalae calcifications associated with disease duration in lipoid proteinosis.

OBJECTIVES: To describe imaging findings of central nervous system involvement in patients with lipoid proteinosis. METHODS: Patients with lipoid proteinosis followed in the dermatology and neurology departments of the State University of Campinas between 2002 and 2004 were evaluated using high-resolution MRI and computerized tomography (CT). RESULTS: We reviewed the charts of three patients (two women) with lipoid proteinosis with, ages ranging from 5 to 44 years. Symptomatic disease duration ranged from 2 to 39 years. MRI scans showed hypointense signal in FLAIR and T2 images in the amygdalae in two of three patients. Brain CT scans from two patients showed that MRI findings were calcifications. The calcification was more evident in patients with longer disease duration. Epilepsy was identified in one patient with longer disease duration. No other epileptogenic lesion was identified on MRI in this patient. CONCLUSION: Lipoid proteinosis is associated with bilateral amygdalae calcification. These findings were more evident in patients with longer disease duration. Epilepsy, when present, may be related to these calcifications. Patients with lipoid proteinosis should be followed with MRI/CT in order to identify these abnormalities.

Adult↗
PubMed2006

T2-weighted and T2 relaxometry images in patients with medial temporal lobe epilepsy.

PURPOSE: Quantification of increased T2-weighted MRI signal that is associated with hippocampal sclerosis (HS) can be performed through (1) mean of hippocampal signal in single-echo T2 MRI and (2) hippocampal T2 relaxometry. It is not clear whether these two techniques are equivalent. In this study, we compare the hippocampal signal, detected by single-echo T2 quantification and by T2 relaxometry, in patients with medial temporal lobe epilepsy (MTLE). METHODS: We studied magnetic resonance images from 50 MTLE patients and 15 healthy subjects. We compared the quantification of a T2 signal from single echo images to T2 relaxometry, both obtained from a manually traced region of interest (ROI) in coronal slices involving the whole hippocampus. Repeated measures ANOVA was used to evaluate the differences in the distribution of the Z-scores from single-echo T2 quantification and T2 relaxometry within subjects. RESULTS: We observed a significant difference between the measurements obtained from single-echo T2 quantification and T2 relaxometry (P < .001). Measurements from head, body, and tail of the hippocampus were different (P=.04), with a significant interaction between anatomic location and type of measurement used (P= .008). Post hoc paired comparisons revealed that T2 relaxometry yielded greater Z-scores for the body (P= .002) and tail (P < .0001). CONCLUSIONS: For each subject with MTLE, T2 relaxometry was able to detect a higher signal in the body and tail of the hippocampus compared to single-echo T2. This is a possible indicator that T2 relaxometry is more sensitive in detecting T2 abnormalities within the body and tail of the hippocampus in patients with MTLE.

Analysis of Variance↗
PubMed2005

Statistical voxel-wise analysis of ictal SPECT reveals pattern of abnormal perfusion in patients with temporal lobe epilepsy.

OBJECTIVE: To investigate the pattern of perfusion abnormalities in ictal and interictal brain perfusion SPECT images (BSI) from patients with temporal lobe epilepsy (TLE). METHOD: It was acquired interictal and ictal BSI from 24 patients with refractory TLE. BSIs were analyzed by visual inspection and statistical parametric mapping (SPM2). Statistical analysis compared the patients group to a control group of 50 volunteers. The images from patients with left-TLE were left-right flipped. RESULTS: It was not observed significant perfusional differences in interictal scans with SPM. Ictal BSI in SPM analysis revealed hyperperfusion within ipsilateral temporal lobe (epileptogenic focus) and also contralateral parieto-occipital region, ipsilateral posterior cingulate gyrus, occipital lobes and ipsilateral basal ganglia. Ictal BSI also showed areas of hypoperfusion. CONCLUSION: In a group analysis of ictal BSI of patients with TLE, voxel-wise analysis detects a network of distant regions of perfusional alteration which may play active role in seizure genesis and propagation.

Adolescent↗
PubMed2005

Evidence of reversible axonal dysfunction in systemic lupus erythematosus: a proton MRS study.

Our objective was to investigate axonal dysfunction in patients with systemic lupus erythematosus (SLE) using proton magnetic resonance spectroscopy (1H-MRS). We studied prospectively 90 SLE patients (mean age of 32.5 years) and 23 normal volunteers (mean age of 33.8 years). We performed single voxel proton MRS using point resolved spectroscopy sequence over the superior-posterior region of the corpus callosum. We measured signals from N-acetyl compounds [N-acetylaspartate (NAA)] at 2.01 p.p.m., choline-based compounds (Cho) at 3.2 p.p.m. and creatine and phosphocreatine containing compounds (Cr) at 3.0 p.p.m. and determined NAA/Cr ratios. After 12 months, MRI and MRS were repeated in 50 patients and 9 volunteers. Patients were divided according to disease activity (measured by SLE disease activity index) during initial and follow-up MRS. We performed paired t-test and ANOVA with Tukey's post hoc comparisons to evaluate group differences. At study entry, 29 patients had active SLE with involvement of central nervous system (CNS) and 28 patients had active SLE without CNS manifestations. A total of 14 patients had inactive SLE with past CNS presentation, and 19 had inactive SLE without history of CNS involvement. NAA/Cr ratios were significant lower in patients with active SLE, independently of CNS involvement, when compared with patients with inactive SLE (P = 0.005) and controls (P = 0.01). We observed a significant increase in NAA/Cr ratio in 15 patients who had active SLE at initial MRS and inactive SLE at follow-up (P = 0.04). In 10 patients with active SLE both at initial and at follow-up MRS we observed a reduction in NAA/Cr ratio (P = 0.02). By contrast, there was a significant reduction of NAA/Cr ratio in 15 patients who had inactive SLE at initial MRS and active SLE at follow-up (P = 0.001). In 10 patients with inactive SLE both at initial and at follow-up MRS NAA/Cr ratio did not change (P = 0.2). This study shows evidence of axonal dysfunction in patients with active SLE, independently of CNS manifestations that may be reversible, at least in part, during periods of inactivity of disease.

Adult↗
PubMed2005

Cerebral and corpus callosum atrophy in systemic lupus erythematosus.

OBJECTIVE: To determine cerebral and corpus callosum volumes in patients with systemic lupus erythematosus (SLE), using semiautomatic magnetic resonance imaging (MRI) volumetric measurements, and to determine possible relationships between a reduction in cerebral volume and disease duration, total corticosteroid dose, neuropsychiatric manifestations, and the presence of antiphospholipid antibodies. METHODS: We studied 115 consecutive patients with SLE and 44 healthy volunteers. A complete clinical, laboratory, and neurologic evaluation was performed. MRI scans were obtained through a standardized protocol. Sagittal T1-weighted images were used for semiautomatic volumetric measurements. We compared SLE patients with controls using the 2-sample t-test. Analysis of variance was used to test for differences between groups, followed by Tukey's post hoc test for pairwise comparisons, when necessary. Linear regression was used to analyze the association between cerebral atrophy and disease duration and total corticosteroid dose. RESULTS: Cerebral and corpus callosum volumes were significantly smaller in patients with SLE compared with healthy volunteers (P < 0.001). Reduced cerebral and corpus callosum volumes were related to disease duration (P < 0.001). Patients with a history of central nervous system (CNS) involvement more frequently had a reduction in cerebral and corpus callosum volumes (P < 0.001). Patients with cognitive impairment had significantly reduced corpus callosum and cerebral volumes when compared with SLE patients without cognitive impairment (P = 0.001). Cerebral and corpus callosum volumes were not associated with the total corticosteroid dose or the presence of antiphospholipid antibodies. CONCLUSION: In patients with SLE, a reduction in cerebral and corpus callosum volumes is associated with disease duration, a history of CNS involvement, and cognitive impairment. The total corticosteroid dose and the presence of antiphospholipid antibodies were not associated with more pronounced atrophy.

Adult↗
PubMed2005

Antiepileptic drugs: a study of 1028 cases registered by the Sao Paulo Intoxication Control Center.

PURPOSE: To illustrate the profile of the cases of intoxications by antiepileptic drugs (AEDs) registered within a large urban area during the period of 1 year. METHODS: A cross-sectional observational study was performed in the Intoxication Control Center of the Sao Paulo City Hospital. We evaluated 6535 medical consults of intoxication cases involving prescription and over-the-counter drugs in 2001. We selected and analyzed the cases involving AEDs. Statistical analysis was performed in order to evaluate the frequency of different drug types and the circumstance of drug exposure. RESULTS: The most frequently observed AEDs were phenobarbital, carbamazepine, diazepam, and clonazepam. The frequency of intoxication cases among different age groups did not significantly differ according to the drug type. The circumstances involving AEDs intoxication were analogous to the circumstances of the cases of intoxication involving all other medications (p>0.05). CONCLUSIONS: There are a large number of intoxications involving AEDs. Imposing a restriction access to AEDs can be deleterious to patients that depend on AEDs, however, a strict program of AEDs distribution should be considered to reduce the cases of AED intoxication.

Age Distribution↗
PubMed2004

The role of neuroimaging in the investigation of patients with single seizures, febrile seizures, or refractory partial seizures.

Seizures are a symptom of an underlying brain disorder. The accurate identification of the nature of the disease generating the seizures facilitates treatment and can prevent further brain damage. The understanding of the physiopathology underlying the seizures has been greatly enhanced by the possibility to examine these patients with advanced forms of neuroimaging. Among different forms of investigation, neuroimaging techniques play a major role in diagnosis and decision-making in the care of patients with epilepsy. We review the contributions of current methods of imaging in the investigation of patients with single seizures, febrile seizures or refractory seizures, assessing the practical aspects, benefits, and operational costs of various neuroimaging techniques. The focus is on MRI, which is the imaging modality of choice for outpatient investigation. We also assessed the benefits from CT scans, which remain the first option for emergency seizure assessment. The aim was to evaluate how the structural, functional and metabolic information provided by modern techniques of neuroimaging decreases the need for additional investigation and speeds the management of these epileptic disorders. This makes it possible to accurately define the location and the nature of the epileptogenic lesions related to seizures.

Brain↗
PubMed2004

Epilepsy due to a destructive brain lesion caused by a scorpion sting.

BACKGROUND: Symptomatic acute epileptic seizures may occur in up to 5% of individuals, especially children, with scorpion stings. The occurrence of a long-lasting brain lesion or the development of epilepsy after a scorpion sting has never been observed. OBJECTIVE: To describe the development of epilepsy secondary to an extensive hemispheric destructive brain lesion after a scorpion sting. PATIENT: A 15-year-old with a moderate global cognitive impairment and a mild left hemiparesis, with seizures occurring approximately once monthly. RESULTS: The mother reported that the patient at the age of 4 years was stung by a brown scorpion, Tityus serrulatus. The patient soon developed local pain and paresthesias followed by diaphoresis and somnolence. Approximately 24 hours after the sting, she began to convulse. She was then taken to a hospital where she achieved suboptimal seizure control, with daily tonic-clonic seizures and left hemiplegia during the following week. During our clinical investigation, her routine electroencephalogram showed the presence of interictal spikes and diffuse slowing in the right brain hemisphere. Magnetic resonance imaging showed a widespread destructive lesion of her right cerebral hemisphere affecting both the cortical and subcortical structures. CONCLUSION: This is a rare illustration of the biological effects of the toxin of T serrulatus concerning its excitotoxicity and the potential to induce a brain lesion of an epileptogenic nature.

Animals↗
PubMed2004

Protocol for volumetric segmentation of medial temporal structures using high-resolution 3-D magnetic resonance imaging.

Quantitative analysis of brain structures in normal subjects and in different neurological conditions can be carried out in vivo through magnetic resonance imaging (MRI) volumetric studies. The use of high-resolution MRI combined with image post-processing that allows simultaneous multiplanar view may facilitate volumetric segmentation of temporal lobe structures. We define a protocol for volumetric studies of medial temporal lobe structures using high-resolution MR images and we studied 30 healthy subjects (19 women; mean age, 33 years; age range, 21-55 years). Images underwent field non-homogeneity correction and linear stereotaxic transformation into a standard space. Structures of interest comprised temporopolar, entorhinal, perirhinal, parahippocampal cortices, hippocampus, and the amygdala. Segmentation was carried out with multiplanar assessment. There was no statistically significant left/right-sided asymmetry concerning any structure analyzed. Neither gender nor age influenced the volumes obtained. The coefficient of repeatability showed no significant difference of intra- and interobserver measurements. Imaging post-processing and simultaneous multiplanar view of high-resolution MRI facilitates volumetric assessment of the medial portion of the temporal lobe with strict adherence to anatomic landmarks. This protocol shows no significant inter- and intraobserver variations and thus is reliable for longitudinal studies.

Adult↗
PubMed2003

[National demonstration project on epilepsy in Brazil].

Epilepsy is the most prevalent non-communicable serious neurological condition worldwide. Unfortunately, the majority of people with epilepsy in low-income countries do not receive appropriate treatment. Stigmatisation is the rule. In this setting, the World Health Organisation, the International League against Epilepsy and the International Bureau for Epilepsy launched the Global Campaign against Epilepsy in 1997. This entered its second phase in 2001 and as part of it has set up demonstration projects in the People's Republic of China, Zimbabwe, Senegal and, more recently, in Brazil. The objective of the demonstration projects is to show, through methodological evaluation, that it is possible to establish a model of treatment for people with epilepsy in primary health care settings. The Brazilian demonstration project has targeted regions in Campinas and S o Jose do Rio Preto, both in Sao Paulo State. A task force has been established to assess strategies to expand this project nationwide.

Brazil↗
PubMed2003

Number and viability of parasite influence seizure frequency in children with neurocysticercosis.

We investigated the relationship between CT findings - number and the viability phase of the parasites - and the seizure frequency in children with neurocysticercosis before and short-term after antiepileptic drug (AED) introduction. We only found a significant interaction between stage of parasitic infection and number of lesions on seizure frequency after AED treatment. Patients with more than five lesions on active or transitional stages had higher seizure frequency predicting a worse short-term prognosis.

Adolescent↗