Magnetic resonance imaging in hereditary and idiopathic ataxia.

We used magnetic resonance imaging (MRI) to study brain and spinal cord morphology in hereditary and idiopathic ataxia. Our interest was in whether the classical neuropathologic categories--cerebellar cortical atrophy (CCA), olivopontocerebellar atrophy (OPCA), and spinal atrophy (SA)--could be identified in vivo and which clinical phenotype corresponded to which morphologic category. To this end, we measured the size of the cerebellar vermis, cerebellar hemispheres, fourth ventricle, middle cerebellar peduncles, basis pontis, medulla oblongata, and cervical spinal cord on T1-weighted images of 61 patients and 24 healthy controls. Five patients with Friedreich's ataxia (n = 7) and all with late-onset Friedreich's ataxia (n = 3) had SA without major involvement of the brainstem or cerebellum. Morphologic findings in patients with early-onset cerebellar ataxia with retained tendon reflexes (n = 11) were heterogeneous: six patients had MRI findings compatible with CCA, and two patients had a combination of SA and CCA. The three remaining patients had an atypical pattern of atrophy. Similarly, the morphologic changes in patients with autosomal-dominant cerebellar ataxia with additional noncerebellar symptoms (ADCA-I; n = 13) were nonuniform: atrophic changes typical for CCA, OPCA, or SA were each present in one case, four patients had a combination of OPCA and SA, and the remaining patients could not be assigned to one of the morphologic categories. In autosomal-dominant cerebellar ataxia with a pure cerebellar syndrome (ADCA-III; n = 6), all patients except one had CCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Conventional high resolution versus fast T(2)-weighted MR imaging of the heart: assessment of reperfusion induced myocardial injury in an animal model.

Cardiac image quality in terms of spatial resolution and signal contrast was assessed for conventional and newly developed T(2)-weighted fast spin-echo imaging with high k-space segmentation. The capability in revealing regional myocardial edema and cellular damage was examined by a porcine model using histopathologic correlation. Twelve porcine hearts were excised from slaughtered animals and instantly perfused with 1000 mL cold cardioplegic solution. After 4 h of cold ischemia the hearts were reperfused for one hour using a "Langendorff" perfusion model followed by MR imaging at 1.5 Tesla. Three additional pig hearts served as controls and were studied by MR directly after harvesting. Histopathological analysis of regional tissue changes was performed macro- and microscopically. Short axis T(2)-weighted (3000/45 and 90) high quality fast spin-echo (FSE) images were recorded without cardiac action and signal intensity was correlated with histology. These images also served as gold standard for evaluation of newly developed faster sequences allowing measuring times shorter than 20 s. Fast T(2)-weighted imaging comprised single-slice fast spin echo (moderate echo train length of 23 echoes, FSE(m)), and multi-slice single-shot half-Fourier fast spin-echo (71 echoes, FSE(HASTE)) sequences, supplemented by versions with inversion recovery preparation (FSE(m)IR and FSE(HASTE)IR). Systolic function after reperfusion was restored in 10 porcine hearts. Tissue alterations included myocardial edema and contraction band necrosis which was found to be most severe in myocardium with maximum T(2) SI. Especially FSE(m) and FSE(m)IR sequences allowed differentiation of all categories of tissue damage on a high level of significance. In contrast, single-shot FSE(HASTE) and FSE(HASTE)IR sequences did not provide sufficient image quality to discriminate moderate and severe myocardial damage (p > 0.05). Different degrees of myocardial injury after ischemia and reperfusion can be staged by MR imaging, especially using conventional high resolution T(2)-weighted FSE sequences. The animal study indicates that fast T(2)-weighted FSE(m) and FSE(m)IR sequences lead to superior image quality and diagnostic accuracy compared to FSE(HASTE) and FSE(HASTE)IR imaging.

[MR tomography studies of myocardial function and perfusion after myocardial infarct]. / MR-tomographische Untersuchung myokardialer Funktion und Perfusion nach Myokardinfarkt.

PURPOSE: With the advent of fast pulse sequences, MR imaging of myocardial function and perfusion in ischaemic heart disease has become possible. Prior studies examined either myocardial perfusion or systolic wall motion. We intended to establish an examination procedure to simultaneously investigate regional myocardial motility and perfusion in patients 7-14 days after myocardial infarction. METHODS: A Turbo-FLASH 2D sequence was optimised to maximise image contrast between normal and malperfused myocardium after Gd-injection using a calculation model basing on the Bloch equation. Calculated values for trigger delay TD, inversion time TI and flip angle alpha were confirmed in a Gd-phantom and healthy volunteers. Subsequently, myocardial motility was studied (cine FLASH 2D sequence) and in slice positions with reduced wall thickening first pass and post contrast studies after 2-10 minutes were performed using the optimised Turbo-FLASH sequence. RESULTS: First pass SI-differences of normal compared to malperfused myocardium vary in relation to TD, TI and alpha in a relevant degree. Reduced myocardial motility was found with a sensitivity of 81% and specificity of 96%. Pathological perfusion patterns were detectable in all of these patients. CONCLUSIONS: A combined examination of motility and perfusion is possible by means of MRI and information about the status of postinfarct myocardium can be obtained.

Maximizing the extent of resection and survival benefit of patients in glioblastoma surgery: high-field iMRI versus conventional and 5-ALA-assisted surgery.

AIMS: A safe total resection followed by adjuvant chemoradiotherapy should be the primary goal in the treatment of glioblastomas (GBMs) to enable patients the longest survival possible. 5-aminolevulinic acid (5-ALA)- and intraoperative MRI (iMRI)-assisted surgery, have been shown in prospective randomized trials to significantly improve the extent of resection (EOR) and subsequently survival of patients with GBMs. No direct comparison of surgical results between both techniques has been published to date. We analyzed the additional value of iMRI in glioblastoma surgery compared to conventional surgery with and without 5-ALA. METHODS: Residual tumor volumes, clinical parameters and 6-month progression-free survival (6M-PFS) rates after GBM resection were analyzed retrospectively for 117 patients after conventional, 5-ALA and iMRI-assisted surgery. RESULTS: Mean residual tumor volume (range) after iMRI-assisted surgery [0.5 (0.0-4.7) cm(3)] was significantly smaller compared to the residual tumor volume after 5-ALA-guided surgery [1.9 (0.0-13.2) cm(3); p = .022], which again was significantly smaller than in conventional white-light surgery [4.7 (0.0-30.6) cm(3); p = .007]. Total resections were significantly more common in iMRI- (74%) than in 5-ALA-assisted (46%, p = .05) or white-light surgery (13%, p = .03). Improvement of the EOR by using iMRI was safely achievable as peri- and postoperative morbidities were comparable between cohorts. Total resections increased 6M-PFS from 32% to 45%. CONCLUSIONS: Analysis of residual tumor volumes, total resections and neurological outcomes demonstrate that iMRI may be significantly superior to 5-ALA and white-light surgery for glioblastomas at comparable peri- and postoperative morbidities. Longer 6M-PFS was observed in patients with total resections.

Are recommended phototherapy thresholds safe enough for extremely low birth weight (ELBW) infants? A report on 2 ELBW infants with kernicterus despite only moderate hyperbilirubinemia.

Two extremely low birth weight (ELBW) infants developed characteristic signs of kernicterus at 4 and 8 months corrected age despite only moderate neonatal hyperbilirubinemia (peak serum bilirubin <10 g/dl) and phototherapy being applied according to current guidelines. Both girls were from twin pregnancies and had fetal complications (donor in a twin-twin transfusion syndrome and acardius-acranius malformation in the second twin, respectively), connatal anemia (initial hematocrit 30%), and mild acidosis after birth. They had been neurologically normal at discharge except for abnormal otoacustic emissions (OAE). At the time kernicterus was diagnosed, both infants were nearly deaf, showed severe psychomotor retardation with dystonic features and had marked bilateral hyperintensities in the globus pallidum on MRI. Based on these and similar cases from the literature, we question whether current phototherapy guidelines are appropriate for high-risk ELBW infants. Lower thresholds may be preferable, at least if additional risk factors, such as anemia, are present.

[Correlation of diffusion-weighted magnetic resonance imaging with neurological deficits in sporadic Creutzfeldt-Jakob Disease]. / Korrelation von diffusionsgewichtetem MRI und neurologischer Symptomatik bei der sporadischen Form der Creutzfeldt-Jakob-Krankheit.

This case report describes the sporadic Creutzfeldt-Jakob disease (CJD) of a 53-year-old man who initially complained about vertigo and dizziness. Within 18 weeks, he developed impaired memory, hemineglect, and sensory impairment of the left half of the body. A CSF tap was positive for 14-3-3 protein and showed increased tau protein, neuron-specific enolase (NSE), and the astroglial protein S-100 B. The EEG showed right temporal sharp waves without periodicity. Diffusion-weighted MRI revealed hyperintensities in the right temporo-occipital cortex which corresponded well with hypometabolic areas in a PET scan and the neurological and neuropsychological deficits. The morphological FLAIR T2 MRI showed no pathological changes. Within 20 weeks, the patient developed severe dementia with decreased spatial orientation and myoclonia, became incontinent, and was confined to bed. He died within 22 weeks after the first presentation of symptoms.

Proton MR spectroscopy with metabolite-nulling reveals elevated macromolecules in acute multiple sclerosis.

Proton magnetic resonance spectroscopy has shown elevated signals in the spectral region of lipids in acute multiple sclerosis lesions. The metabolite-nulling technique allows the separation of macromolecules from other metabolites, such as lactate, N-acetyl-aspartate, creatine, choline and myo-inositol. Using this technique in studies on multiple sclerosis patients, we were able to differentiate macromolecules biochemically in acute and chronic multiple sclerosis lesions. Ten patients with acute, contrast-enhancing multiple sclerosis lesions, 10 patients with chronic lesions and 10 healthy control subjects were investigated with a 1.5 T whole body system, using a stimulated echo acquisition mode (STEAM) sequence with metabolite-nulling and outer volume saturation. Metabolites and macromolecules were quantitated absolutely. The 0.9 and 1.3 parts per million (p.p.m.) resonances of the macromolecules were significantly elevated in acute lesions compared with chronic lesions and healthy controls (P < 0.001 for 0.9 p.p.m., P < 0.05 for 1.3 p.p.m.). The macromolecular resonances at 2.1 and 3.0 p.p.m. in acute and chronic lesions were normal. N-acetyl-aspartate was significantly reduced in acute and chronic lesions compared with controls (P < 0.05 and P < 0.01, respectively). Choline was significantly elevated in acute lesions compared with controls (P < 0.05). Up to now, elevated resonances at 0.9 and 1.3 p.p.m. in acute lesions have been interpreted as lipids. In metabolite-nulled spectra, the macromolecular resonances did not fit those of lipids and might have been due to proteins or polypeptides containing the amino acids alanine, threonine, valine, leucine and isoleucine. These account for approximately 40% of the amino acids of myelin proteolipid protein and for approximately 20% of myelin basic protein. The increased macromolecular resonances at 0.9 and 1.3 p.p.m. may be interpreted as biochemical markers of myelin fragments and may be used as reliable markers of acute multiple sclerosis lesions as they provide clear discrimination among acute and chronic lesions and controls.

Reversible brain shrinkage in abstinent alcoholics, measured by MRI.

Magnetic resonance imaging of the intracranial CSF volume was compared before and after 5 weeks of confirmed abstinence in 9 alcohol-dependent patients. All patients showed a highly significant reduction in CSF volume in accordance with reexpansion of the brain after alcohol abstinence. T2 values for white matter, estimated by linear regression from 16 echoes of a CPGM sequence, however, showed no significant increase such as occurs in rehydration. This indicates, that alcohol-induced reversible brain atrophy cannot be attributed to fluctuation of free water in the brain only.

Alexander disease--classification revisited and isolation of a neonatal form.

Alexander disease is usually classified according to the age of onset, e.g. an infantile form with onset during the first two years of life, a juvenile form with onset in childhood, mainly school age. It has been recognized, however, that the clinical course can be very variable within these groups. Thus, this clinical classification is not a useful predictor of severity and progression of the disease. This is demonstrated here on the basis of the history of seven own patients and a literature review. Only an onset in very early infancy, during the neonatal period, seemed to be associated with a rather uniform pattern of disease course, often leading to early death. This neonatal form showed very stereotyped symptoms, in part different from later onset: Early, often intractable, generalized seizures; hydrocephalus with raised intracranial pressure due to aqueductal stenosis because of pathological astroglia proliferation; lack of developmental progression but without prominent spasticity or ataxia; elevated CSF protein content. This was associated with the well-established neuroradiological findings, e.g. severe white matter affection with fronto-temporal predominance, involvement of basal ganglia and periventricular enhancement as an obligatory symptom. The identification of this early onset form is especially important as seizures and signs of raised intracranial pressure may mislead the diagnosis.

Coregistration of EEG and fMRI in a simple motor task.

The purpose of this study was to evaluate the adequacy of coregistration of movement-related cortical potentials (MRCPs) and functional magnetic resonance imaging (fMRI) data in the primary sensorimotor cortex. Data were acquired in four normal subjects during right and left simple index finger movements. In fMRI (single-slice, 1.5 Tesla, T2*-weighted FLASH sequence), contralateral primary motor (M1) and primary sensory cortex (S1) were activated in all subjects. Spatiotemporal dipole modelling of electric MRCP generators (BESA) revealed two main sources in the central region contralateral to the moving finger. Both sources were tangentially oriented. Their configuration was consistent with source locations in the anterior (M1) and posterior (S1) banks of the central sulcus. Accordingly, the M1 source generated the pre-movement, the S1 source largely the immediate post-movement MRCP component. Taken together, MRCP modelling and fMRI data indicated a phasic sequential activation pattern of mostly sulcal portions of contralateral M1 and S1. After coregistration of anatomical MRI, fMRI, and dipole modelling results, the average 3D-distance between fMRI activation areas and MRCP source locations was 18.6 mm (SD 7.6), with the largest deviation in the anterior-posterior direction (12.1+/-9.5 mm). Coregistration inaccuracies of similar magnitude (approximately 17 mm) have been reported previously with MEG and PET or fMRI. We conclude, therefore, that the combination of EEG and fMRI is a promising technique for validation of electrophysiological source models and for evaluation of human functional brain anatomy with both adequate spatial and temporal resolution.

MR imaging and (1)H spectroscopy of brain metabolites in hepatic encephalopathy: time-course of renormalization after liver transplantation.

PURPOSE: To evaluate changes in hydrogen 1 magnetic resonance (MR) spectroscopic findings in overt or subclinical hepatic encephalopathy (HE) after liver transplantation and to compare these changes with clinical outcomes and basal ganglia high signal intensity (BGH). MATERIALS AND METHODS: Twenty-two patients scheduled for liver transplantation and 17 healthy control subjects were examined with (1)H MR spectroscopy and standard nonenhanced MR imaging. Eight patients underwent complete MR imaging and (1)H spectroscopic examinations before liver transplantation and at 3-4-week, 12-28-week, and 10-12-month follow-up after liver transplantation. RESULTS: Before liver transplantation, typical (1)H spectroscopic changes-decreased myo-inositol (mI)/creatine (Cr) and choline (Cho)/Cr ratios and an elevated glutamine and glutamate (Glx)/Cr ratio-were found in 21 patients. Eighteen patients had BGH at T1-weighted imaging. Three to 7 months after liver transplantation, the mI/Cr and Glx/Cr ratios were within the normal range in five of eight and eight of eight patients, respectively, without any residual signs of subclinical or overt HE; however, at MR imaging, seven patients still had BGH. CONCLUSION: After successful liver transplantation, renormalization of HE-specific brain metabolite changes is detected at (1)H spectroscopy and precedes the disappearance of BGH. The neuropsychologic signs of subclinical or overt HE follow the changes seen at (1)H spectroscopy rather than those seen at MR imaging.