Wernicke encephalopathy: MR findings at clinical presentation in twenty-six alcoholic and nonalcoholic patients.

BACKGROUND AND PURPOSE: Wernicke encephalopathy is a severe neurologic disorder that results from a dietary vitamin B1 deficiency. It is characterized by changes in consciousness, ocular abnormalities, and ataxia. This study was undertaken to analyze and compare findings on MR imaging and neurologic symptoms at clinical presentations of patients with Wernicke encephalopathy with and without a history of alcohol abuse. MATERIALS AND METHODS: A multicenter study group retrospectively reviewed MR brain imaging findings, clinical histories, and presentations of 26 patients (14 female, 12 male) diagnosed between 1999 and 2006 with Wernicke encephalopathy. The age range was 6-81 years (mean age, 46 .6+/-19 years). RESULTS: Fifty percent of the patients had a history of alcohol abuse, and 50% had no history of alcohol abuse. Eighty percent showed changes in consciousness, 77% had ocular symptoms, and 54% had ataxia. Only 38% of the patients showed the classic triad of the disease at clinical presentation. At MR examination, 85% of the patients showed symmetric lesions in the medial thalami and the periventricular region of the third ventricle, 65% in the periaqueductal area, 58% in the mamillary bodies, 38% in the tectal plate, and 8% in the dorsal medulla. Contrast enhancement of the mamillary bodies was statistically positively correlated with the alcohol abuse group. CONCLUSIONS: Our study confirms the usefulness of MR in reaching a prompt diagnosis of Wernicke encephalopathy to avoid irreversible damage to brain tissue. Contrast enhancement in the mamillary bodies is a typical finding of the disease in the alcoholic population.

Atypical Clinical Picture in a Patient with Benign Occipital Epilepsy: Diagnostic Contribution of Morpho-Functional MR. A Case Report.

Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) is a maternally inherited disease due to mitochondrial DNA (mtDNA) point mutations. The clinical phenotype varies in relation to the systems affected, age at onset and disease severity. The characteristic signs of MELAS are nausea and vomiting due to acidosis, headache, epilepsy, ataxia or generalized weakness, ophthalmoplegia, motor and sensory focal neurological deficits. The clinical course may improve due to partial regression of the typical lesions, but the prognosis is usually adverse. A 19-year-old man with a diagnosis of benign occipital epilepsy and resumption of seizure activity with focal occipital attacks since the age of 14 years came to our attention for the recent onset of drug-resistant electroclinical seizures of long duration with complex symptoms, where the dominant clinical feature was an intense, persistent bilateral periorbital migraine with nausea and vomiting, scintillation scotomata and blurring of vision. MR studies were performed at our institution in the immediate post-seizure phase and then at one week, three and six months. The acute-phase morphological scans showed a right cortical-subcortical area with altered signal in the occipitopolar region that was hypointense on T1 and hyperintense on T2 and FLAIR, with cortical thickening and effacement of the sulci. Contrast-enhanced scans did not demonstrate BBB alterations. The DWI scans showed a right temporo-occipital cortical area with higher signal intensity. In the subsequent examinations the area with altered signal shrank gradually and significantly in parallel with improvement in clinical conditions. The diagnostic hypothesis of benign occipital epilepsy was consistent neither with the clinical course, characterized by persistent headache, visual disturbance and refractoriness to antiepileptic drugs, nor with the temporal-occipital cortical MR findings, which resembled ischemic lesions but displayed a non-territorial pattern as well as reversibility over time. These elements guided in the diagnosis of MELAS, which was subsequently confirmed by identification of the typical gene mutation. On DWI the stroke-like lesions of MELAS are seen more frequently as focal hyperintense areas compared with healthy parenchyma. Such high signal intensity likely corresponds to T2 shine-through rather than cytotoxic edema. Indeed, several studies have demonstrated that in acute-phase scans of MELAS stroke-like lesions DWI hyperintensity is associated with increased ADC values that are not associated with restricted water diffusivity, reflecting the metabolic rather than anoxic-ischemic nature of these changes. In the present case, morphological MR associated with DWI was very helpful in guiding the diagnosis by demonstrating some pathognomonic features of MELAS stroke-like lesions such as cortical-subcortical involvement of the posterior hemispheres, the non-territorial pattern, lesion reversibility and the pathophysiological role of vasogenic edema in inducing an increase in extracellular water and thus in diffusion values.

Leigh Syndrome: an MR Study of Three Cases.

Leigh syndrome (LS), or subacute necrotizing encephalomyelopathy, is the most common childhood mitochondrial encephalopathy, accounting for more than 50% of cases in this age group. Its estimated incidence is 1:40,000 - 1:77,000 liveborn infants a year. LS is a rare progressive multisystem fatal disorder inherited by autosomal recessive, X-linked and maternal transmission. Clinical onset is predominantly in the first two years of life (average: six months); 50% of patients die within a year, even though there are later- and even adult-onset forms with a more protracted evolution. LS is due to a deficit of various respiratory chain and Krebs cycle enzymes resulting in insufficient production of adenosine triphosphate (ATP), in particular cytochrome-c-oxidase (COX), pyruvate carboxylase, pyruvate dehydrogenase complex and complex I of the respiratory chain, which share an autosomal recessive and X-linked mode of transmission. Cases with maternal inheritance (MILS) are due to a mitochondrial DNA (mtDNA) point mutation. LS is clinically heterogeneous in relation to the severity of the metabolic dysfunction and is characterized by muscle involvement and especially CNS disorders, particularly psychomotor retardation, ocular symptoms, hypotonia and pyramidal signs. Death is most commonly due to respiratory failure, status epilepticus and sudden coma. The major neuropathological findings, first described by Leigh in 1951, are symmetrical foci of spongy necrosis associated with vessel proliferation and reactive gliosis in basal nuclei, brainstem and thalamus grey matter. The neuronal metabolic alteration can also affect the white matter, resulting in delayed myelination or hypomyelination. The diagnosis rests on clinical signs, elevated CSF lactate, pyruvate and alanine, and biochemical and neuroradiological data. We describe two patients with LS studied with morphological MR associated with diffusion and spectroscopy techniques to assess the diagnostic potential of standard MR imaging and establish whether the association of functional MR methods can improve its diagnostic accuracy. A case of LS with a post-mortem MR study is also described. Three patients with a diagnosis of LS based on clinical, CSF and laboratory data were studied on a GE SIGNA EXCITE 1.5 T unit using an eight-channel phased-array head coil to acquire standard sequences (SE T1; TSE DP T2; FLAIR) and echo-planar diffusion-weighted sequences (DWI; b= 1000 s/mm2) with calculation of ADC maps. The spectroscopic study used single-voxel (TE/TR ms = 144/1500) and multi-voxel techniques (TE/TR ms = 144/1000) at the level of the basal nuclei. Bilateral and symmetrical involvement of basal nuclei grey matter with T2 hyperintensity was a consistent finding in the morphological MR study. In one patient, associated white matter involvement with T2 hyperintensity in periventricular and retrotrigonal areas reflected delayed myelination or hypomyelination. The deep grey matter changes, sometimes associated with white matter lesions, suggested a diagnosis of subacute necrotizing encephalomyelopathy, in line with the literature. Acute-phase ADC values in affected areas were lower than those of normal grey and white matter and displayed signal hyperintensity on DWI. Reduced ADC values are associated with restricted water diffusivity typical of cytotoxic edema. Spectroscopy showed a high lactate peak, reflecting altered anaerobic glycolysis, and a reduced NAA peak in affected areas, which are however non-specific findings. The most informative study in these patients is standard MR associated with functional techniques, which can confirm the diagnosis obtained with morphological imaging.

Effects of ionic and non-ionic paramagnetic contrast media on brain bio-electric activity.

The potential neurotoxic effects of gadolinium (Gd)-based compounds for enhanced MRI are not completely understood. We investigated electroencephalography changes induced by ionic and non-ionic Gd-based compounds administered intravenously in patients affected by lesions of the central nervous system (CNS) characterized by breakdown of the blood-brain barrier. This double-blind, randomized, study of two parallel groups involved 40 patients scheduled for an MRI examination with contrast medium for known CNS lesions. Twenty patients were randomly allocated to receive non-ionic Gd-DTPA-BMA/gadodiamide and 20 patients were randomly allocated to receive ionic Gd-DTPA/gadopentetate. For both groups the intravenous dose was 0.1 mmol/kg body weight. Three electroencephalography recordings were performed: immediately before, during, and 15 min after contrast medium injection. Mean and peak frequencies of the beta band and absolute power of the delta and/or theta bands of the electroencephalograms (EEGs) were noted. Each EEG was also evaluated to detect any alterations. The values of the 8-12 Hz band showed a significant increase during and after injection versus baseline in the gadopentetate group (P<0.05) and a significant decrease during injection in the gadodiamide group (P<0.05). The values of the 12-16 Hz band showed a significant increase versus baseline during and after injection in the gadopentetate group (P<0.05). The electrophysiological method based on computerised spectral analysis is a sensitive tool for evaluating effects of contrast media on brain bio-electric activity. EEG changes are detectable, even in the absence of any clinical evidence. It would appear that there might be clinical advantages in the use of non-ionic compounds.

Magnetic Resonance applications in dental implantology: technical notes and preliminary results.

PURPOSE: To evaluate the possible use of Magnetic Resonance Imaging (MRI) in the field of dental implantology, for identifying the mandibular nerve, as proposed by several authors. MATERIALS AND METHODS: MRI was used for the study of the mandible in ten subjects (five healthy volunteers and five subjects awaiting dental implants). Imaging was performed on a 1.0-T MR scanner with a brain coil. T2 TSE, T1 spin-echo and T2 gradient-echo sequences were performed, both parallel and perpendicular to the horizontal portion of the mandible, with a thickness of 3 mm. RESULTS: In all the subjects MRI clearly identified the intraosseous course of the inferior alveolar neurovascular bundle within the mandibular canal. CONCLUSIONS: MRI appears useful for the depiction of the mandibular canal before dental implantation. Further studies are required to compare the accuracy of MRI and CT based on a statistically significant sample.

Joubert syndrome with associated corpus callosum agenesis.

In 1969, Joubert et al. studied a family where four of six children had a severe clinical condition with episodic alternate hyperpnoea and apnoea, hypotonia, ataxia, psychomotor delay, and abnormal ocular movements. Two of the four had agenesis of the posterior-inferior part of the cerebellar vermis and two had complete agenesis of the vermis. We report a 5-month-old girl with Joubert syndrome in whom MRI shows both features typical of this condition and associated corpus callosum agenesis. To our knowledge, complete callosal agenesis has been infrequently reported in children with Joubert syndrome; consequently, it might be regarded as a casual finding. Nevertheless, the hypothesis of a developmental abnormality of midline structures extended to the supratentorial compartment is rather attractive.

Spontaneous intracranial hypotension: the value of brain measurements in diagnosis by MRI.

Caudal brain displacement is inconstantly reported as an MRI feature of spontaneous intracranial hypotension (SIH). We reviewed the clinical data and MRI of eight patients diagnosed as having SIH and investigated the possibility of more precise assessment. On midsagittal images we measured four anatomical landmarks: the position of the cerebellar tonsils, fourth ventricle, and infundibular recess, plus the angle between the bicommissural line and a line tangential to the floor of the fourth ventricle; midsagittal images from 89 normal controls were also measured. On statistical analysis, all measurements differed in the two groups, and the difference was significant for the cerebellar tonsils, fourth ventricle, and infundibular recess. Some overlap between patients and controls was found for each measurement; however, all the patients had two (two patients) or more (six) values outside the range in normal controls range or not above their 1st quartile. Measurement of the position of the third ventricle seemed particularly sensitive. We suggest that examination of midsagittal images can help in diagnosing clinically suspected SIH.

Multicentric glioma with unusual clinical presentation.

Multiple glioma is a well-recognized but uncommon entity. They are grouped in two categories: multifocal and multicentric gliomas. Multifocal gliomas grow through dissemination along an established route, spreading through commissural pathways, CSF channels, or the blood or by local extension through satellite formation; at the opposite end of the spectrum, multicentric gliomas are widely separated lesions whose simultaneous presence cannot be attributed to any of the above pathways. Reports in the literature refer to single cases or small series of multicentric gliomas, almost always in adult patients, their occurrence in children being even less frequent. We report the case of a 12-year-old boy with multicentric glioma, atypical acute clinical onset and fast growth of three other tumors in 8 months, and then discuss the problems of diagnosis and therapy.

Hippocampus and parahippocampal gyrus linear measurements based on magnetic resonance in Alzheimer's disease.

MRI-based linear measurements of the hippocampus and parahippocampal gyrus complex (HPC) discriminated 39 subjects with probable Alzheimer's disease, from 15 patients with other dementias and 33 miscellaneous controls without evidence of dementia. The best discriminating parameter was the left height of the HPC at the level of the mammillary bodies, with a sensitivity of 79.49% and a specificity of 68.75%. The diagnostic value of these results is discussed considering the volumetric data found in the current literature.

Randomised, double-blind, placebo-controlled study of pivagabine in neurasthenia.

One hundred and eighteen patients with neurasthenia, as defined by ICD 10 (International Classification of Diseases), participated in a randomised, double-blind, placebo-controlled trial of pivagabine (4-[(2,2-dimethyl-1-oxopropyl)amino]butanoic acid, CAS 69542-93-4, Tonerg). Pivagabine 1800 mg/d was administered orally for four weeks. At the end of the trial, active medication was significantly superior to placebo on the Clinical Global Impression (CGI) improvement of illness scale. In addition, pivagabine treatment reduced the physical and mental fatigability of patients, and increased their sense of well-being.