Early diagnosis of herpes simplex encephalitis by MRI.

The mortality rate of herpes simplex encephalitis (HSE) may be reduced by antiviral therapy, but early administration of the drug and therefore early diagnosis are essential. In our experience with four cases, MRI is the most sensitive noninvasive test in early diagnosis of HSE due to its high sensitivity to inflammatory increased brain water content, and it is superior to CT in localizing the pathognomonic lesions of the limbic system.

Functional MRI of human primary somatosensory and motor cortex during median nerve stimulation.

OBJECTIVES: Somatosensory evoked potential (SEP) studies suggested that some early cortical SEP components may be generated in the primary motor cortex (M1) rather than the primary somatosensory cortex (S1). METHODS: We now used functional magnetic resonance imaging (fMRI) to study activation of S1 and M1 by electrical median nerve stimulation in healthy volunteers. RESULTS: The hand areas of both S1 and M1 showed significant activation (correlation coefficients >0.45) in 7 of 9 subjects (activated volume S1 > M1). For comparison, a sequential finger opposition task significantly activated S1 in 7 and M1 in all 9 subjects (activated volume M1 > S1). CONCLUSIONS: These data show that the electrical stimuli used for SEP recording lead to a functional activation of S1 as well as M1.

Ischemic stroke and migraine in childhood: coincidence or causal relation?

Although migraine is an accepted cause of cerebral infarction in adults, this association is less well recognized in children. We present two children with migraine and cerebral infarction, which we regard as migrainous stroke, though neither patient fulfills all criteria of the International Headache Society for the diagnosis of migrainous infarction. Review of the literature concerning examples of migraine-associated stroke in childhood suggests that these criteria are too restrictive to comprise the majority of migrainous strokes, especially in this age group.

Intramedullary cavernous angiomas.

Two cases of histologically verified intramedullary cavernous angiomas at C3 and D5-6 are presented. Both patients suffered progressive myelopathy with intermittent improvement. In both cases preoperative diagnosis was possible by means of magnetic resonance imaging using spin echo techniques, fast imaging, and phase display, while spinal angiography was not helpful. Laminectomy and total removal of the tumors were performed with temporary increased neurological deficits. It is thought that magnetic resonance imaging provides a useful diagnostic tool in these tumors and is also essential for planning surgical strategy.

Cerebral activation in patients with somatoform pain disorder exposed to pain and stress: an fMRI study.

Patients with somatoform pain disorders are supposed to suffer from an early acquired defect in stress regulation. In order to look for common alterations of the pain- and stress-responsive cortical areas, we prospectively recorded cerebral activations induced by pin-prick pain, by cognitive stress and emotional stress using functional magnetic resonance imaging (fMRI) in a group of 17 patients and an age-matched control group. In addition, the hippocampal volumes of both groups were measured. Patients showed increased activations of the known pain-processing areas (thalamus, basal ganglia, operculo-insular cortex), but also of some prefrontal, temporal and parietal regions during first pain exposure and of temporal and parietal areas during cognitive stress, but reduced activations during emotional stress. In contrast to these functional differences, hippocampal volume was not significantly reduced in patients. Although the superior temporal gyrus was the only common area of an "overactivation" in patients in the pain and stress condition, findings of our study support the current concept of mechanisms involved in somatoform pain disorders: central processing of pain and of cognitive stress is increased in patients possibly due to exaggerated memory and/or anticipation of pain exposure and to a disturbance of stress-regulating systems which has to be worked out on a cortical level in more detail. Our finding of a reduced responsiveness to emotional stress is surprising, but not contradictive to these results because some sort of neglect or coping mechanisms may have developed over time as a response to early adversities.

Abscess of the orbit arising 48 h after root canal treatment of a maxillary first molar.

AIM: To discuss a rare, but severe complication arising following routine root canal treatment. SUMMARY: An orbital abscess is reported that occurred following routine root canal treatment. A young, healthy female patient, with no history of chronic paranasal infection had undergone root canal treatment of the right maxillary first molar. On hospital admission, she presented with extensive periorbital swelling and discreet diplopia. Computed tomography imaging identified massive purulent sinusitis and subsequent involvement of the orbit via the inferior and medial orbital wall within 48 h after completion of root canal treatment. Immediate surgical drainage of the maxillary sinus and the orbit was established and a high dose of perioperative antibiotics (Amoxicillin/Clavulanic acid, Gentamycin, Metronidazole) were administered. Vision remained undisturbed and mobility of the globe recovered within 10 days. KEY LEARNING POINTS: Rapid exacerbation of a periapical inflammation may occur following root canal treatment and may even involve the orbit. A typical speed of disease progression or ophthalmic symptoms should alert the clinician to at least consider unusual early orbital spread of odontogenic infection. When extra-alveolar spread and especially orbital spread is suspected, immediate referral to a maxillofacial or other specialized unit is mandatory.

[Acoustic schwannoma with progressive hearing loss in children. A case report]. / Akustikusneurinom als Ursache einer progredienten kindlichen Hörstörung.

BACKGROUND: Neurinomas of the vestibulocochlear nerve unrelated to neurofibromatosis in children are extremely rare. Only 20 cases in children under the age of 16 are reported in the literature. Progressive unilateral hearing loss, tinnitus, vertigo and neurological deficits due to cranial nerve or brainstem compression are clinical signs. PATIENT AND RESULTS: We report on the case of a 12-years-old girl with an unilateral hearing loss, progressing to total deafness. Otoacoustic emissions were normal. In the MRI a large cerebellopontine angle tumor was found, identified as schwannoma of the vestibulocochlear nerve. CONCLUSIONS: The importance of MR Imaging in children with progressive unilateral hearing loss is demonstrated in this case.

The value of paraxial slices in MR-imaging of spinal cord disease.

Paraxial slices in MRI of the spinal cord reveal information about anatomical structures and pathological processes not available from orthogonal plane images or other diagnostic methods. They also yield a profit in diminishing the artifacts that occur from heart movement and respiration when triggering is not employed.

Advantage of magnetic resonance imaging in the diagnosis of cerebral infections.

18 patients with cerebral infections were investigated with a 1.5 Tesla-Magnetom. The results are compared to CT-findings obtained at the same time. In the majority of cases (n = 11) MR is superior to CT because it allows earlier detection of the disease, a more exact definition of the spread and a more detailed representation of complex inflammatory processes. MRI should rank first among all examination methods, especially in the determination of herpes simplex-encephalitis as it allows earlier detection and treatment of this disease.

MR imaging of esthesioneuroblastoma.

The CT, magnetic resonance (MR), and histological features of a case of esthesioneuroblastoma, an uncommon tumor arising from the olfactory epithelium of the nasal vault are reported. The response to radiotherapy was followed up by MR imaging.

Brain electrical source analysis of primary cortical components of the tibial nerve somatosensory evoked potential using regional sources.

Tibial nerve somatosensory evoked potentials (SEPs) show higher amplitudes ipsilateral to the side of stimulation, whereas subdural recordings revealed a source in the foot area of the contralateral hemisphere. We now investigated this paradoxical lateralization by performing a brain electrical source analysis in the P40 time window (34-46 ms). The tibial nerve was stimulated behind the ankle (8 subjects). On each side, 2048 stimuli were applied twice. SEPs were recorded using 32 magnetic resonance imaging (MRI)-verified electrode positions (bandpass 0.5-500 Hz). In each case, the P40 amplitude was higher ipsilaterally (0.45 +/- 0.14 microV) than contralaterally (-0.49 +/- 0.16 microV). The best fitting regional source, however, was always located in the contralateral hemisphere with a mean distance of 8.2 +/- 4.3 mm from the midline. The positivity pointed ipsilaterally shifting from a frontal orientation (P37) to a parietal direction (P40). The P40 dipole moment was 2.5 times stronger than the dipole moment of P37, which makes P40 most prominent in EEG recordings. However, with its oblique dipole orientation compared to the tangential P37 dipole, it is systematically underestimated in MEG. Dipole orientations explained interindividual variability of scalp potential distribution. SEP amplitudes were smaller when generated in the dominant (left) hemisphere. This is explained by deeper located sources (5.4 +/- 1.6 mm) with a more tangential orientation (delta theta = 17.5 +/- 2.3 degrees) in the left hemisphere.

Proton magnetic resonance spectroscopy in dementia of Alzheimer type.

Reduced N-acetyl aspartate (NAA) and increased myo-inositol (MI) levels have been reported in patients with dementia of Alzheimer type (DAT) in comparison with controls. We wished to assess the validity of these findings and to evaluate possible correlations of metabolite proportions with cognitive dysfunction in DAT. Twelve patients with DAT and 10 healthy age-matched controls were included. The severity of dementia was assessed using different scales including the Mini-Mental State Examination. MRS was performed with a conventional 1.5 Tesla scanner in a single voxel in the centrum semi-ovale (TE = 30 ms or TE = 136 ms; TR = 1500 ms). The evaluation of MRS results was limited by low interrater, intermeasurement (different echo times) and test-retest reliabilities, by a high interindividual variance and by the failure to measure absolute metabolite concentrations. These problems in mind, it was remarkable that previously reported reductions of NAA levels in patients with DAT could be reproduced in the present sample. The proportion of NAA was diminished in demented subjects in comparison with controls (37% vs 44.90%, short TE). A non-significant trend towards minor reductions of creatine, choline and MI proportions in these subjects might indicate that proportions of other metabolites necessarily increase when NAA is reduced. Cognitive dysfunction of demented subjects was significantly correlated with reductions of NAA, but not with increases of MI. Due to the present technical and methodological problems and to the non-specificity of findings, proton MRS cannot be applied to support the diagnosis of DAT in a clinical setting.

Amygdala-hippocampal atrophy and memory performance in dementia of Alzheimer type.

The aim of the present study was to examine the involvement of brain structures, especially the amygdala-hippocampal complex, in dementia of Alzheimer type (DAT), and to assess the relation of amygdala-hippocampal atrophy with memory dysfunction. 14 patients with DAT and 10 healthy age-matched controls were examined with different neuropsychologic tests including the UCLA-Auditory Verbal Learning Test. MRI was performed with a conventional 1.5-tesla scanner. Atrophy was found in many brain structures of demented subjects in comparison with healthy age-matched controls. The volumes of amygdala-hippocampal complexes and of the temporal lobes of demented subjects were more reduced than the total brain volume and other structures. Memory dysfunction was highly correlated with atrophy of the amygdala-hippocampal complexes and of the temporal lobes. Consequently, DAT seems to affect the amygdala-hippocampal complex and their related function (i.e. memory) more than other cerebral structures, but cerebral degeneration in DAT is not restricted to these structures.