Erika Vörös

White matter microstructural alterations in migraine: A diffusion-weighted MRI study

Summary White matter disintegration, as measured by diffusion‐weighted MRI, is reported in migraineurs, and is speculated to be either a marker of possible white matter disintegration or maladaptive plasticity. Abstract Migraine is a common and disabling neurological disease. The pathomechanism that underlies the disorder is not entirely understood, and reliable biomarkers are missing. In the current analysis we looked for microstructural alterations of the brain white matter in migraine patients by means of diffusion‐weighted magnetic resonance imaging. The measurements were carried out with a novel approach based on fine‐tuned nonlinear registration and nonparametric permutation test in an alignment‐invariant tract representation (Tract‐Based Spatial Statistics). We found reduced fractional anisotropy in the right frontal white matter cluster of migraine patients. In the same region we also found increased mean diffusivity and increased radial diffusivity. The probabilistic tractography showed connection of this cluster to other parts of the pain network (orbitofrontal cortex, insula, thalamus, dorsal midbrain). We speculate that these findings reflect maladaptive plastic changes or white matter disintegration.

Correlations between clinical symptoms, working memory functions and structural brain abnormalities in men with schizophrenia.

Thirteen male patients with schizophrenia and thirteen male normal control subjects were compared by magnetic resonance imaging (MRI) on volumes of the straight gyrus (SG), anterior cingulate gyrus, middle frontal gyrus, hippocampus, third ventricle, cavum septi pellucidi, total brain volume and intracranial volume. In addition, neuropsychological tasks were used to measure working memory and executive functions. Healthy volunteers and schizophrenic patients showed no significant differences in mean values for volumes of regions of interests. In the case of the SG, we found a significant difference in laterality: the tendency toward left dominance in healthy volunteers changed to significant right dominance in patients. The schizophrenic patients showed lower performance in working memory tasks, and strongly significant group differences were observed in measures of neurological signs assessed by the Neurological Evaluation Scale (NES). Negative symptoms correlated with the level of spatial working memory and executive functions. Negative symptoms also correlated with the volume of the right hippocampus, while the rate of anhedonia negatively correlated with the relative volume of the left SG.

Favorable Early Outcome of Carotid Artery Stenting Without Protection Devices

Background and Purpose— Protection devices are increasingly used in carotid artery stenting. However, no randomized trial has been conducted to evaluate the efficacy of such devices, and arguments have also been formulated against their routine use. We set out to investigate the complication rates associated with carotid artery stenting performed without protection devices. Applicability of covered stents in the carotid system was also evaluated. Methods— Between January 2001 and July 2003, 245 consecutive patients (260 hemispheres) underwent carotid artery stenting. No protection devices were applied. Covered stents were implanted in 31 (12.1%) cases. The incidence of complications during the intervention and the subsequent 30-day follow-up period was recorded. Results— The technical success rate was 98.8%. One postprocedural nonneurological death (0.4%) occurred. Neurological complications (inclusive of transient ischemic attacks) were observed in 14 cases (5.4%). The rate of major complications (death, major stroke, and myocardial infarction) was 1.6% among the symptomatic and 1.5% among the asymptomatic cases. The rate of minor strokes was 3.2% in the symptomatic and 1.5% in the asymptomatic group. Of the neurological complications, 64.3% occurred postprocedurally. No ipsilateral neurological complications were detected in the subgroup treated with covered stents. Conclusions— Carotid artery stenting without protection devices appears to be safe. Most of the neurological complications could not have been prevented with protection devices, because they occurred after the intervention. The application of covered stents may reduce the rate of embolization-related complications in the periprocedural period.

Donor site angiography before mandibular reconstruction with fibula free flap

The use of fibular free flaps has become established as a reliable and popular method for reconstruction of segmental mandibular defects. The role of routine preoperative angiography remains controversial. Sixty four digital subtraction angiograms were studied in a series of 39 consecutive patients clinically judged to be satisfactory candidates for fibula free transfer. Angiographic findings revealed vascular anomalies in 10 extremities (15.6%). Regarding the high potential for significant donor site morbidity authors consider vascular imaging essential part of preoperative evaluation.

Complex hallucinations following occipital lobe damage

Visual hallucinations may accompany many neurological and psychiatric disorders. A common localization principle is that lesions to the early sensory cortices lead to elementary hallucinations, whereas complex perceptual experiences are related to the pathology of higher‐level cortical regions. We report the case of a patient who experienced complex, non‐stereotyped, multimodal (visual and somatosensory) hallucinations following an acute ischaemic vascular lesion in the right medial occipital lobe. This illustrates that the phenomenology of hallucinations not necessarily reflects the exact localization of cerebral pathology. Instead, the damaged area may serve as a focus of an abnormally activated neuronal network.

Target identification for stereotactic thalamotomy using diffusion tractography.

Background Stereotactic targets for thalamotomy are usually derived from population-based coordinates. Individual anatomy is used only to scale the coordinates based on the location of some internal guide points. While on conventional MR imaging the thalamic nuclei are indistinguishable, recently it has become possible to identify individual thalamic nuclei using different connectivity profiles, as defined by MR diffusion tractography. Methodology and Principal Findings Here we investigated the inter-individual variation of the location of target nuclei for thalamotomy: the putative ventralis oralis posterior (Vop) and the ventral intermedius (Vim) nucleus as defined by probabilistic tractography. We showed that the mean inter-individual distance of the peak Vop location is 7.33 mm and 7.42 mm for Vim. The mean overlap between individual Vop nuclei was 40.2% and it was 31.8% for Vim nuclei. As a proof of concept, we also present a patient who underwent Vop thalamotomy for untreatable tremor caused by traumatic brain injury and another patient who underwent Vim thalamotomy for essential tremor. The probabilistic tractography indicated that the successful tremor control was achieved with lesions in the Vop and Vim respectively. Conclusions Our data call attention to the need for a better appreciation of the individual anatomy when planning stereotactic functional neurosurgery.

Dissociation between Attentional Set Shifting and Habit Learning: a Longitudinal Case Study

We report a patient (ST) with predominant damage to the right neostriatum, caused by a rare cerebral angiitis. The testing procedure was focused on attentional set shifting (Wisconsin Card Sorting Test: WCST) and habit learning (probabilistic classification learning; PCL). ST showed impairments in the WCST, digit span backward, alphabet span, and PCL procedures, whereas he exhibited spared IQ, short-term verbal memory, object recognition, episodic and semantic memory. After 1 month of steroid therapy, there was a significant improvement in the WCST, digit span backward and alphabet span tests, whereas PCL remained severely impaired. The three control patients with damage to the parietal lobe displayed normal learning rates in PCL. These results suggest that separate frontostriatal mechanisms exist for attentional set shifting and habit learning.

Neurovascular Pulsatile Compression and Neurosurgical Decompression of the Rostral Ventrolateral Medulla in Medically Resistant Hypertensive Patients

Background/Aims: In cases of severe primary hypertension not responding to conventional medical therapy, neurovascular pulsatile compression of the rostral ventrolateral medulla on the left side may be considered as an etiological factor in the hypertension. Through neurosurgical decompression, the blood pressure can be reduced in these cases, and the conventional medication can also become more effective. Methods:The authors retrospectively analysed the changes in the blood pressure and therapy of patients with or without neurosurgical decompression over a 2-year period. The 2-year data were available for 9 operated and 7 non-operated patients with neurovascular compression. The data of control examinations performed 1, 3, 6, 12 and 24 months after the intervention (or after MR-angiography in the non-operated cases) were analysed. Results: After the decompression, both the systolic and diastolic blood pressure decreased significantly and permanently in all cases, and there was an improved response to the medication. In the non-operated group, the blood pressure did not change significantly during the 2 years. Conclusion: In severe hypertension that does not respond to conventional therapy, neurosurgical decompression of the brain stem on the left side can guarantee a long-lasting blood pressure reduction and a better response to antihypertensive medication.

Three-dimensional time-of-flight MR angiography in trigeminal neuralgia on a 0.5-T system

Abstract The goal of this study was to analyze the diagnostic value of three-dimensional time-of-flight magnetic resonance angiography (3D TOF MRA), performed on a 0.5-T system in the detection of neurovascular compression in patients with trigeminal neuralgia (TN). One hundred seventy-two TN patients were examined using plain and contrast-enhanced 3D TOF MRA on a 0.5-T system. Maximum intensity projection (MIP) reconstruction was performed in three standard planes. Both the original and the reconstructed images were studied to search for vascular compression shown by close neurovascular contact and/or dislocation of the trigeminal nerve. Forty-two TN patients underwent surgical exploration of the posterior fossa. Results of MRA were compared with clinical data in all cases and to results of surgery in the surgically treated cases. Neurovascular contact at the root entry zone of the trigeminal nerve was detected on the symptomatic side in 94 patients, and on the asymptomatic side in 12 patients. Sensitivity, specificity, accuracy, as well as positive and negative predictive value of 3D TOF MRA in the detection of neurovascular compression in the patient group undergoing surgery, were 97.6, 92.5, 95.0, 93.0, and 97.4 %, respectively. Three-dimensional TOF MRA performed on a 0.5-T system appears to be not less effective than similar examinations by higher field strength devices in the detection of neurovascular contact. This sequence accurately demonstrates the presence of neurovascular compression, and in this way valuable information may be achieved for the planning of surgical therapy of patients with trigeminal neuralgia.

Magnetic resonance imaging in Tolosa-Hunt syndrome

Magnetic resonance imaging is an important diagnostic tool in Tolosa-Hunt syndrome, but the timing of this procedure is important. Tolosa-Hunt syndrome (THS) is the eponym of painful ophthalmoplegia caused by granulomatous inflammation in the cavernous sinus, superior orbital fissure or orbit. The diagnostic criteria of THS, recently revised by the International Headache Society, are: one or more episodes of unilateral orbital pain persisting for weeks if untreated; paresis of one or more of the third, fourth and/or sixth cranial nerves and/or demonstration of granuloma by MRI or biopsy; paresis coincides with the onset of pain or follows it within 2 weeks; pain and paresis resolve within 72 h when treated adequately with corticosteroids and other causes have been excluded. In addition, careful follow-up is suggested [3]. A 12-year-old girl with right periorbital pain and sixth nerve palsy was investigated. She complained of double vision, initially lasting for some minutes only; however, 2 weeks later, it recurred with a brief headache. After a 3-day break, a more lasting paresis of the right abducens nerve developed without any pain. Neurological examination showed no abnormality apart from the abducens paresis. EEG, CSF and blood studies gave