Cerebral involvement in axonal Charcot-Marie-Tooth neuropathy caused by mitofusin2 mutations

Mutations in the mitofusin 2 (MFN2) gene are a major cause of primary axonal Charcot- Marie-Tooth (CMT) neuropathy. This study aims at further characterization of cerebral white matter alterations observed in patients with MFN2 mutations. Molecular genetic, magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and diffusion tensor imaging (DTI) investigations were performed in four unrelated patients aged 7 to 38 years with early onset axonal CMT neuropathy. Three distinct and so far undescribed MFN2 mutations were detected. Two patients had secondary macrocephaly and mild diffuse predominantly periventricular white matter alterations on MRI. In addition, one boy had symmetrical T2-hyperintensities in both thalami. Two patients had optic atrophy, one of them with normal MRI. In three patients proton MRS revealed elevated concentrations of total N-acetyl compounds (neuronal marker), total creatine (found in all cells) and myo-inositol (astrocytic marker) in cerebral white and gray matter though with regional variation. These alterations were most pronounced in the two patients with abnormal MRI. DTI of these patients revealed mild reductions of fractional anisotropy and mild increase of mean diffusivity in white matter. The present findings indicate an enhanced cellular density in cerebral white matter of MFN2 neuropathy which is primarily due to a reactive gliosis without axonal damage and possibly accompanied by mild demyelination.     

Conventional MRI and MR spectroscopy in nonclassical mitochondrial disease: report of three patients with mitochondrial DNA deletion

Objects The objectives were to present magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) findings in three patients with deletion on mitochondrial DNA (mtDNA) and nonclassical mitochondrial disorders (NCMD), correlating these findings with the percentage of deleted mtDNA.Results Our study confirms the high prevalence of white matter (WM), basal ganglia, and posterior fossa lesions in NCMD, ranging from mild to severe involvement. The subcortical WM, caudate, thalamus, globus pallidus, and dorsal brain stem were more frequently affected. A lactate peak was the most frequent finding at the MRS. We found a correlation between the percentage of mtDNA deletion and degree of MRS abnormalities.Conclusions Our findings showed that MRS is a useful investigational tool in patients with NCMD. Supplementary studies are necessary to elucidate the correlation of quantitative mtDNA deletion and neuroimaging phenotype.     

Hypomyelination and reversible white matter attenuation in 3-phosphoglycerate dehydrogenase deficiency

White matter abnormalities are a feature of many inborn errors of metabolism and magnetic resonance imaging (MRI) of the brain has become an important tool in the diagnostic work-up of these disorders. Recently, patients were reported with a potentially treatable disorder of serine biosynthesis. They presented with congenital microcephaly, severe psychomotor retardation and intractable seizures. Low concentrations of the amino acids serine, glycine as well as 5-methyltetrahydrofolate were found in plasma and CSF and were due to a deficiency of the enzyme 3-phosphoglycerate dehydrogenase (3-PGDH). We studied four patients aged 10 months to 7 years by MRI before and after treatment with amino acids with a follow-up of 16 months to 6 years. Magnetic resonance spectroscopy (MRS) was performed in two patients at 4 and 16 months of treatment. Pre-treatment MRI demonstrated hypomyelination and profound white matter attenuation in all patients. During treatment, a significant increase in white matter volume was found and a progress of myelination in two patients. The most striking finding on MRS during treatment was an elevated level of white matter choline. Serine biosynthesis defects have to be considered in the differential diagnosis of patients with mental retardation, microcephaly, seizures, and on MRI hypomyelination and white matter attenuation.     

Magnetic resonance imaging volumetric and phosphorus 31 magnetic resonance spectroscopy measurements in schizophrenia.

The purpose of this study was to examine the relationship between phosphorus magnetic resonance spectroscopy (31P MRS) parameters and left prefrontal volumes in both patients with schizophrenia and healthy subjects. 31P MRS parameters and magnetic resonance imaging (MRI) volumetric data were collected in the left prefrontal region in 10 patients with schizophrenia and 10 healthy subjects of comparable age, handedness, sex, educational level, and parental educational level. No correlations were found between any MRS parameter and grey matter volumes in the combined subjects. Phosphomonoester (PME) and grey matter volumes, however, were both correlated negatively with age. PMEs were found to be decreased, and calculated intracellular magnesium ([Mg2+]intra) was found to be increased in the patients with schizophrenia compared with healthy subjects after adjusting for left prefrontal grey and white matter, total brain volume, and age. These findings suggest that cortical grey and white manner volumes are not directly related to PME and [Mg2+]intra abnormalities in schizophrenia patients.     

Olanzapine increases grey and white matter volumes in the caudate nucleus of patients with schizophrenia

There are inconsistent reports regarding the caudate nucleus volume in patients with schizophrenia compared with healthy subjects. The reason for this is that neuroleptic medication may affect the volume of the caudate nucleus in schizophrenic patients. To clarify which antipsychotic medication changes the volume of the caudate nucleus in patients with schizophrenia, we measured the volumes of grey and white matter in the caudate nucleus of schizophrenic patients. Ten patients with schizophrenia were examined twice by magnetic resonance imaging (MRI) to measure the grey and white matter volumes in the caudate nucleus. After the first MRI examination, all the patients were treated with olanzapine. The clinical responses were evaluated by the positive and negative rating scale. When the symptoms improved, the patients were examined by a second MRI scan. Ten healthy control subjects also underwent MRI. The schizophrenic patients had reduced volumes of grey and white matter in the caudate nucleus compared to the healthy control subjects. The volumes of grey and white matter in the caudate nucleus of the schizophrenic patients increased after treatment with olanzapine. These findings suggest that treatment with olanzapine may increase the grey and white matter volumes in the caudate nucleus in patients with schizophrenia.     

Proton magnetic resonance spectroscopy of systemic lupus erythematosus involving the central nervous system

We examined 13 patients with neurological manifestations of systemic lupus erythematosus (SLE) based on previous and/or current neurological or psychotic episodes by magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) together with psychiatric and cognitive assessment. MRI was abnormal in 7 patients, showing high signal lesions in the white matter and/or cerebral atrophy. Proton MRS centred on white matter lesions in 5 patients showed a reduction in theN-acetyl aspartate creatine ratio compared with normal appearing white matter in the SLE group and in 10 healthy controls. This pattern of abnormality does not allow differentiation of SLE lesions from the chronic plaques occurring in multiple sclerosis. There was a very high incidence of current psychiatric morbidity in the SLE group, namely in 12 of the 13 patients. There was no correlation between the presence of current psychiatric involvement and/or cognitive dysfunction and abnormalities detected with MRI or MRS.     

Neuroimaging Findings in Hyperargininemia

In hyperarginenemia, there is a defect in argininase enzyme, which is a catalyzer of urea cycle. Though the pathogenesis of neuronal damage in hyperargininemia is not clear, high serum and cerebrospinal fluid arginine levels can be directly related with neuronal damage. In this study, our aim was to assess brain magnetic resonance images and magnetic resonance spectroscopy (MRS) patterns of two siblings with hyperarginenemia. We acquired single voxel MRS from the white matter to show the myelination pattern and to figure out any abnormal peak of metabolite stored due to enzymatic defect. We observed mild cerebral and cerebellar atrophy and infarct at bilateral posterior putamen and insular cortex localization on conventional images and elevated choline/creatine ratios and abnormal peak at 3.8 ppm, most likely representing arginine deposition. To the best of our knowledge, this is the first article revealing the brain MRS pattern of hyperargininemia. We reported the clinical and imaging findings of patients and discuss the correlation.     

Magnetic resonance findings in two episodes of repeated cerebral fat embolisms in a patient with autologous fat injection into the face

We report magnetic resonance image (MRI) and magnetic resonance spectroscopy (MRS) findings in a patient of cerebral fat embolism (CFE) occurred in a 26-year-old woman after an autologous fat injection into the face. After initial neurologic symptom onset, MRI and MRS data were obtained two times to investigate repeated CFE. We obtained the MRS data in the two different time intervals and two different echo times to compare the lesions with normal brain parenchyma. The results of MRS data showed that a decrease in N-acetyl-aspartate, an increase in lactate and a very high early peak of free lipids between 0.9 and 1.4 ppm were obtained at the acute infarcted lesion as compared with normal brain parenchyma. In addition, these findings were more clearly detected on short echo time spectrum rather than long spectrum. A close relationship between the clinical manifestations and MRI and MRS findings of the brain can helpful to distinguish CFE with other conditions and to evaluate the cause materials of infarctions rather than conventional MRI or diffusion-weighted imaging.     

Merosin-negative congenital muscular dystrophy: magnetic resonance spectroscopy findings

Congenital muscular dystrophies (CMD) are heterogeneous group of muscle disorders with autosomal recessive inheritance. Merosin deficiency has been identified in some patients with CMD all of whom also had white matter abnormalities on MRI. In postmortem studies, the brain showed extensive myelin pallor with a spongy appearance of white matter and moderate astrocytosis or demyelination. Direct assessment of neuropathologic aspects of MN-CMD such as demyelination is possible with MR spectroscopy (MRS). Although previous reports have described several neuro-imaging findings of this disease, MRS findings have not been reported in literature. In this case, we report MRS features of a 4-year old girl with MN-CMD. MRS of brain demonstrated that N-acetylaspartate (NAA)/Creatine (Cr) ratio was normal. Increased Choline (Cho)/Cr and Myo-inositol (MI)/Cr ratios were obtained. These findings were interpreted as demyelination and gliosis of white matter.     

Alterations of brain metabolites in metachromatic leukodystrophy as detected by localized proton magnetic resonance spectroscopy in vivo

The brain morphology and chemistry of seven children with late infantile (4/7) and juvenile (3/7) forms of metachromatic leukodystrophy (MLD) were investigated by magnetic resonance imaging (MRI) and localized proton magnetic resonance spectroscopy (MRS). Patients who were examined at least 6 months after the onset of symptoms (6/7) had severe leukodystrophic changes on MRI. Proton MRS revealed a marked reduction of the neuronal markerN-acetylaspartate in white and grey matter and elevated lactate in demyelinated areas. In contrast to other leukodystrophies MLD patients showed a generalized increase of brainmyo-inositol (2- to 3-fold in white matter), indicating a specific role in the pathophysiology of demyelination in MLD.     

Sjögren-Larsson syndrome: clinical and MRI/MRS findings in FALDH-deficient patients

OBJECTIVE: To determine the spectrum of clinical and MRI/1H MRS features of patients with fatty aldehyde dehydrogenase (FALDH) deficiency. BACKGROUND: The Sjogren-Larsson syndrome (SLS) was originally defined as a clinical triad consisting of ichthyosis, spastic di- or tetralegia, and mental retardation, with autosomal recessive inheritance. By now, both the deficiency of the enzyme FALDH, and the genetic mutations on chromosome 17 responsible for this deficiency, have been identified. SLS, defined by fibroblast FALDH deficiency, seems to be a much broader syndrome. METHODS: The clinical findings of 11 FALDH-deficient patients of different ages and one patient with the characteristic SLS-like ichthyosis, but without FALDH deficiency, were evaluated in relation to their cerebral MRI, and to 1H MRS in six patients. RESULTS: The severity of neurologic symptoms showed considerable variation. Fundoscopic perifoveal glistening dots and the characteristic SLS-like ichthyosis were present in all patients. Serial MRI findings showed evidence of retarded myelination and a variable degree of dysmyelination. 1H MRS showed an accumulation of free lipids in the periventricular white matter, even before the stage of visible dysmyelination. CONCLUSIONS: The neurologic consequences of FALDH deficiency show considerable variation. The characteristic pattern of ichthyosis and retinal degeneration are seen consistently, yet they are not pathognomonic. MRI and 1H MRS findings suggest an accumulation of long-chain fatty alcohol intermediates, resulting in retarded myelination and dysmyelination.     

<Superscript>1</Superscript>H MR spectroscopy of gray and white matter in carbon monoxide poisoning

Carbon monoxide (CO) intoxication leads to acute and chronic neurological deficits, but little is known about the specific noxious mechanisms. ¹H magnetic resonance spectroscopy (MRS) may allow insight into the pathophysiology of CO poisoning by monitoring neurochemical disturbances, yet only limited information is available to date on the use of this protocol in determining the neurological effects of CO poisoning. To further examine the short-term and long-term effects of CO on the central nervous system, we have studied seven patients with CO poisoning assessed by gray and white matter MRS, magnetic resonance imaging (MRI) and neuropsychological testing. Five patients suffered from acute high-dose CO intoxication and were in coma for 1–6 days. In these patients, MRI revealed hyperintensities of the white matter and globus pallidus and also showed increased choline (Cho) and decreased N-acetyl aspartate (NAA) ratios to creatine (Cr), predominantly in the white matter. Lactate peaks were detected in two patients during the early phase of high-dose CO poisoning. Two patients with chronic low-dose CO exposure and without loss of consciousness had normal MRI and MRS scans. On follow-up. five of our seven patients had long-lasting intellectual impairment, including one individual with low-dose CO exposure. The MRS results showed persisting biochemical alterations despite the MRI scan showing normalization of morphological changes. In conclusion, the MRS was normal in patients suffering from chronic low-dose CO exposure; in contrast, patients with high-dose exposure showed abnormal gray and white matter levels of NAA/Cr, Cho/Cr and lactate, as detected by ¹H MRS, suggesting disturbances of neuronal function, membrane metabolism and anaerobic energy metabolism, respectively. Early increases in Cho/Cr and decreases of NAA/Cr may be related to a poor long-term outcome, but confirmation by future studies is needed.     

Hemimegalencephaly: Localized Proton Magnetic Resonance Spectroscopy In Vivo

Summary: Two children with hemimegalencephaly were examined by magnetic resonance imaging (MRI) and localized proton MR spectroscopy (MRS). In both cases, structural changes in the enlarged hemisphere included pachy-or polymicrogyria and gliosis of white matter. Associated metabolic disturbances included a dramatic reduction of glutamate and N-acetylaspartate (NAA) in white matter. Less severe or no alterations were noted in cortical gray matter, basal ganglia, and cerebellum. The older child (13 years) showed increased myoinositol in both gray and white matter as well as markedly increased choline-containing compounds in gray matter. Both children also had mildly decreased NAA levels in the white matter of the contralateral hemisphere. The spectroscopic findings indicate loss of vital neuroaxonal tissue and glial cell proliferation. Metabolic disturbances were more pronounced in the older child. The normal-appearing hemisphere was mildly affected in both cases.     

Extensive cerebral white matter abnormality without clinical symptoms: a new hereditary condition?

A 30-year-old father and his 2 sons with slight hyperkinesia and mildly dysmorphic features and their close relatives were examined clinically and with computed tomography (CT) and magnetic resonance imaging (MRI). Neurophysiological and biochemical examinations were normal; however, brain MRI of the father and sons revealed extensive cerebral white matter changes. No radiological progression could be detected at a 13-year follow-up examination of the father, and proton magnetic resonance spectroscopy (MRS) of the father at the age of 30 years was normal. MRI findings in the relatives were normal, suggesting an autosomal dominant syndrome due to a new mutation in the father.     

Magnetic resonance imaging in late-onset ornithine transcarbamylase deficiency

We examined brain magnetic resonance imaging (MRI) in a cohort of seven patients with ornithine transcarbamylase deficiency (OTCD), and correlated MRI findings with clinical manifestations. Seven patients with OTCD, aged 3-27 years, all with a missense mutation, were involved in the study. We classified the OTCD patients clinically into four stages. MR study was performed with a 1.5-T superconducting magnet during asymptomatic periods. MRI revealed white matter lesions in two patients with an advanced clinical stage, i.e. T1 and T2 prolongated round lesions in the deep white matter and posterolateral angle of the lateral ventricle in one patient; small foci of T2 and T1 prolongation in the subcortical white matter in another. Parenchymal lesions, and cerebral and cerebellar atrophy were not found in the other five patients. MRI might be normal in the early stage of the disease, and progress in proportion to the clinical stage of OTCD. OTCD should be considered as a differential diagnosis of small foci in the white matter in children.     

The role of non-conventional MR techniques to study multiple sclerosis patients

Conventional magnetic resonance imaging (MRI) lacks pathological specificity to the heterogeneous substrates of multiple sclerosis (MS) lesions and is not able to detect subtle, disease-related changes in the normal-appearing white matter (NAWM). As a consequence, the correlation between MRI findings and the long-term evolution of MS is moderate at best. To overcome the limitations of conventional MRI, new quantitative magnetic resonance (MR) techniques, such as cell-specific imaging, magnetization transfer imaging (MTI), proton magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI) and functional MR imaging (fMRI) have all been recently applied to the study of MS. These techniques should provide more accurate and pathologically specific estimates of the MS lesion burden than conventional MR and should improve our understanding of the mechanisms leading to MS-related irreversible disability.     

Proton MR spectroscopy of nonketotic hyperglycinemia

Proton magnetic resonance spectroscopy (MRS) can noninvasively detect brain metabolites in vivo. A girl with the neonatal type of nonketotic hyperglycinemia was studied by MRS using a long-echo-time point-resolved technique. The proton spectrum from a volume of 15 x 15 x 15 mm cube located in her left parietal white matter exhibited a glycine signal at 3.5 ppm. Subsequent measurements (3 months to 2 years of age) showed a time course of glycine/creatine ratio similar to the changes of the glycine levels in the blood and cerebrospinal fluid. Our findings suggest that MRS is a noninvasive diagnostic tool useful in monitoring the brain glycine level directly in patients with nonketotic hyperglycinemia.     

Carbon Monoxide Brain Toxicity: Clinical, Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy, and Neuropsychological Effects in 9 People

Carbon monoxide (CO) exposure is a common cause of toxic brain damage, whereby effects range from transient neurological dysfunction to coma and death. A spectrum of severity of magnetic resonance imaging (MRI) findings after CO brain toxicity, including globus pallidus and white matter lesions, is well documented. Reports of MR spectroscopy (MRS) findings re main sparse. This article reports 9 people exposed to CO because of an apartment house's faulty gas heater. Four, with transient loss of consciousness after chronic moderate level CO exposure, suffered intellectual impairment without MRI abnormalities. The MRS of 1 individual demonstrated decreased n-acetyl aspartase in the basal ganglia, bilaterally. Of 5 exposed to high levels for about 12 hours, 1 died prior to clinical and/or MRI evaluation. One who suffered coma recovered but was lost to evaluation. Three, who were unconscious for hours to days, exhibited T2 MRI white matter signal abnormalities. MRS showed decreased basal ganglia n-acetyl aspartase in 2. One of these suffers a Parkinsonian syndrome. All 3 are intellectually impaired. This study demonstrates that although MRI and MRS are useful markers of CO-induced brain damage, they are not always sensitive to resultant intellectual dysfunction.     

MR spectroscopy in 18q syndrome suggesting other than hypomyelination

We reported a 5-year-old boy with 18q^- syndrome who showed typical magnetic resonance imaging (MRI) findings of high signal intensity on T2-weighted imaging, and a slightly high but lower than normal signal on T1-weighted imaging of the white matter. MR spectroscopy (MRS) revealed increased concentrations of creatine, myoinositol and choline with a normal N-acetylaspartate one. The cerebral white matter lesions observed on MRI in patients with 18q^- syndrome have been considered to reflect hypomyelination due to a decrease in myelin basic protein so far, however, MRS suggested reactive astrocytic gliosis and accelerated myelin turnover, which are compatible with recent pathological reports of 18q^- syndrome.     

Proton magnetic resonance spectroscopy in three subacute sclerosing panencephalitis patients: correlation with clinical status

Introduction Subacute sclerosing panencephalitis is progressive, fatal encephalitis caused by a persistent defective measles virus in the central nervous system. The diagnosis is based upon characteristic clinical manifestations, the presence of characteristic periodic EEG discharges, and demonstration of elevated antibody titer against measles in the plasma and cerebrospinal fluid. There has been no correlation between the clinical status and the MRI findings.Methods We performed single voxel magnetic resonance spectroscopy (MRS) on white matter areas that appeared normal or abnormal on conventional MRI in three patients with different clinical stages.Results N-acetyl aspartate:creatine ratios were decreased and choline:creatine ratios were increased in white matter lesions in the late stages of the disease. A lactate peak was observed in a patient in the last stage of the disease. Increased myoinositol:creatine ratio was seen in white matter areas on conventional MRI and in the white matter lesions at early stage of the disease, before neuronal loss.