Landmarks for the Location of the Subthalamic Nucleus Using Magnetic Resonance Imaging

Deep brain stimulation has become an option for advanced Parkinson's disease treatment since the 1990s, but the first reports are from Benabid's team, a French neurosurgeon, in the 1980s. The subthalamic nucleus (STN), more specifically its dorsolateral portion, is the most commonly stimulated brain area. One of the major aspects for a good surgical result is the accurate location of this target. Therefore, the present article aimed to identify landmarks that facilitate and refine the location of the STN using nuclear magnetic resonance imaging (NMRI) of the skull. In order to achieve this goal, a search for articles was performed using the PubMed and Science Direct online databases, and articles regarding the use of NMRI to target STN were included. The precise location of the dorsolateral portion of the STN is fundamental to achieve the best possible effect on motor symptoms and to minimize side effects. One of the most used location methods is the NMRI, associated or not with tomography or ventriculography. The location strategies can be classified as direct and indirect. Landmarks are among the indirect strategies, and the most important ones (red nucleus, Sukeroku sign, dent internal capsule sign, supramammillary commissure, mammillothalamic tract, and interpeduncular cistern) are described in the present article. The various landmarks can be combined to locate with more accuracy the dorsolateral portion of the STN and the ideal position of the electrodes to achieve the best possible clinical result.

Non-Motor Symptom Burdens Are Not Associated with Iron Accumulation in Early Parkinson's Disease: a Quantitative Susceptibility Mapping Study

BACKGROUND: Quantitative susceptibility mapping (QSM) has been used to measure iron accumulation in the deep nuclei of patients with Parkinson's disease (PD). This study examined the relationship between non-motor symptoms (NMSs) and iron accumulation in the deep nuclei of patients with PD. METHODS: The QSM data were acquired from 3-Tesla magnetic resonance imaging (MRI) in 29 patients with early PD and 19 normal controls. The Korean version of the NMS scale (K-NMSS) was used for evaluation of NMSs in patients. The patients were divided into high NMS and low NMS groups. The region-of-interest analyses were performed in the following deep nuclei: red nucleus, substantia nigra pars compacta, substantia nigra pars reticulata, dentate nucleus, globus pallidus, putamen, and head of the caudate nucleus. RESULTS: Thirteen patients had high NMS scores (total K-NMSS score, mean = 32.1), and 16 had low NMS scores (10.6). The QSM values in the deep were not different among the patients with high NMS scores, low NMS scores, and controls. The QSM values were not correlated linearly with K-NMSS total score after adjusting the age at acquisition of brain MRI. CONCLUSION: The study demonstrated that the NMS burdens are not associated with iron accumulation in the deep nuclei of patients with PD. These results suggest that future neuroimaging studies on the pathology of NMSs in PD should use more specific and detailed clinical tools and recruit PD patients with severe NMSs.

Changes in Diffusion Metrics of the Red Nucleus in Chronic Stroke Patients With Severe Corticospinal Tract Injury: A Preliminary Study

OBJECTIVE: To explore plastic changes in the red nucleus (RN) of stroke patients with severe corticospinal tract (CST) injury as a compensatory mechanism for recovery of hand function. METHODS: The moderate group (MG) comprised 5 patients with synergistic hand grasp movement combined with limited extension, and the severe group (SG) included 5 patients with synergistic hand grasp movement alone. The control group (CG) included 5 healthy subjects. Motor assessment was measured by Motricity Index (MI). Diffusion tensor imaging was analyzed using fractional anisotropy (FA) and radial diffusivity (RD) in the individual regions of interest (ROIs)—bilateral internal capsule and anterior pons for CST injury and bilateral RN for rubrospinal tract (RST) injury. RESULTS: The SG showed a significantly lower MI score than the MG mainly due to differences in hand subscores. Significantly reduced FA was observed in both MG and SG compared with CG, while SG showed increased MD and RD in the affected ROIs of CST, and increased FA on the unaffected side compared with CG. However, in the RN ROI, a significantly increased FA and decreased RD on the unaffected side similar to the affected side were found only in the SG. The relative index of FA was lower and RD in SG was higher than in CG in RST. CONCLUSION: The diffusion metrics of RST showed changes in patients with severe CST injury, suggesting that RST may play a role in the recovery of hand function in patients with severe CST injury.

An Unusual Case of Japanese Encephalitis Involving Unilateral Deep Gray Matter and Temporal Lobe on Diffusion-Weighted MRI

Acute Japanese encephalitis (JE) is an endemic viral infectious disease in various parts of Far East and Southeast Asian countries including Korea. Bilateral thalami are the most common involving sites in JE. Other areas including the basal ganglia, substantia nigra, red nucleus, pons, cerebral cortex and cerebellum may be also involved. We report an extremely unusual brain diffusion-weighted MR imaging (DWI) findings in a 53-year-old man with serologically proven JE involving unilateral deep gray matter and temporal lobe, which shows multifocal high signal intensities in left thalamus, left substantia nigra, left caudate nucleus and left medial temporal cortex on T2-weighted image and DWI with iso-intensity on apparent diffusion coefficient (ADC) map.

Holmes' Tremor Associated with Bilateral Hypertrophic Olivary Degeneration Following Brain Stem Hemorrhage: A Case Report

Holmes' tremor is a condition characterized by a mixture of postural, rest, and action tremors due to midbrain lesions in the vicinity of the red nucleus. Hypertrophic olivary degeneration (HOD) is a rare type of neuronal degeneration involving the dento-rubro-olivary pathway and may present clinically as Holmes tremor. We report on a 59-year-old female patient who developed Holmes tremor in association with bilateral HOD, following brain stem hemorrhage.

T2 Relaxometry Using 3.0-Tesla Magnetic Resonance Imaging of the Brain in Early- and Late-Onset Restless Legs Syndrome

BACKGROUND AND PURPOSE: Previous T2 relaxometry studies have provided evidence for regional brain iron deficiency in patients with restless legs syndrome (RLS). Measurement of the iron content in several brain regions, and in particular the substantia nigra (SN), in early- and late-onset RLS patients using T2 relaxometry have yielded inconsistent results. In this study the regional iron content was assessed in patients with early- and late-onset RLS using magnetic resonance imaging (MRI), and compared the results with those in controls. METHODS: Thirty-seven patients with idiopathic RLS (20 with early onset and 17 with late onset) and 40 control subjects were studied using a 3.0-tesla MRI with a gradient-echo sampling of free induction decay and echo pulse sequence. The regions of interest in the brain were measured independently by two trained analysts using software known as medical image processing, analysis, and visualization. The results were compared and a correlation analysis was conducted to investigate which brain areas were related to RLS clinical variables. RESULTS: The iron index in the SN was significantly lower in patients with late-onset RLS than in controls (p=0.034), while in patients with early-onset RLS there was no significant difference. There was no significant correlation between the SN iron index of the late-onset RLS group and clinical variables such as disease severity. CONCLUSIONS: Late-onset RLS is associated with decreased iron content in the SN. This finding supports the hypothesis that regional brain iron deficiency plays a role in the pathophysiology of late-onset RLS.

Fluid Attenuated Inversion Recovery (FLAIR) Imaging of the Normal Brain: Comparisons between Under the Conditions of 3.0 Tesla and 1.5 Tesla

OBJECTIVE: The aim of this study was to evaluate the differences in normal brain MRI findings between under 3.0 Tesla (T) and 1.5T MRI conditions with the use of the fluid attenuated inversion recovery (FLAIR) sequences. MATERIALS AND METHODS: Eleven normal adults underwent imaging with the use of the FLAIR sequences on both 1.5T and 3.0T scanners. Two neuroradiologists compared the signal intensity (SI) of the centrum semiovale (CS), pulvinar thalami (PT) and normal iron deposit structures (IDSs) on the 3.0T and 1.5T FLAIR images, and they evaluated three MRI findings qualitatively: high SI of CS; low SI of PT; low SI of IDS. We also evaluated signal-to-noise ratios (SNRs) for the CS, PT, red nucleus and cerebellar dentate nucleus on the FLAIR images. RESULTS: Based on qualitative analyses, the 3.0T FLAIR images showed all three MRI findings for all cases. Low SI for the PT in seven cases (64%), high SI of the CS in one case (9%) and low SI of the cerebellar dentate nucleus in one case (9%) were visualized only on 3.0T FLAIR images. The mean SNRs of the PT, red nucleus and dentate nucleus in patients where 3.0T FLAIR imaging was performed were significantly lower as compared with the SNRs on 1.5T FLAIR images. The SNR of the CS was not significantly different between under the two magnetic field strengths (p > 0.05). CONCLUSION: We have demonstrated that normal, high and low SIs of the CS, PT and IDS on 3.0T FLAIR images were depicted more frequently and more prominently as compared with those on 1.5T FLAIR images in normal adult brains.

Relationship between graded spinal cord injury and rubrospinal MEPs in rats / 中国应用生理学杂志

<p><b>AIM</b>To explore an accurate neurophysiological technique that demonstrates small functional differences after spinal cord injury and assesses therapeutic interventions.</p><p><b>METHODS</b>A modified weight drop (WD) technique was used at T8 in rats to build graded spinal cord injury model. Rubrospinal MEPs were recorded at T13 epidurally to monitor spinal cord function in end week 4 after graded spinal cord injury. The efficacy of this techniques to monitor spinal cord function was compared to BBB locomotor rating scale and histologic evaluation.</p><p><b>RESULTS</b>A characteristic peak complex of rubrospinal MEPs in sham-operated group consisted of 5-7 positive waves and 4-5 negative waves emerging after red nucleus stimulation. The summed peak to peak amplitude (for practical reasons, called peak amplitude) was (195.25 +/- 34.35) microV and decreased following spinal cord injury. The latency of the first peak (positive wave) was (1.57 +/- 0.15) ms and prolonged following spinal cord injury. Significant Linear relationship existed between the peak amplitude and the BBB scores (r = 0.79) and between the peak amplitude and the residual matter obtained from the section with maximum tissue damage( r = 0.87). The close relationship between the latency of the first peak and the BBB scores (r = -0.88) and between the latency of the first peak and residual matter (r = -0.86) were observed.</p><p><b>CONCLUSION</b>Amplitudes and latencies of rubrospinal MEPs are very valuable parameters to demonstrate small function differences. Rubrospinal MEPs can be used as a reliable measure for motor function prognosis after spinal cord injury.</p>

study on postnatal development and ageing changes of red nucleus in the albino rat

The red nucleus is one of the most important structures in the midbrain tegmentum. It plays an important role in the control of motor activities. The aim of the present work is to demonstrate the structure of the red nucleus and the characteristics of its constituent neurons during the various stages of postnatal development, it also includes the study of the ageing effect on the features of its cells. In this work, a total number of 40 albino rats was used. The following postnatal age groups of animals were studied; newly born, seven days, fifteen days and three months old [adult rats] in addition to the aged group of animals [two years old rats]. Animals were sacrificed and the midbrain region was dissected. In each age group, three midbrain specimens were processed to be studied by Einarson's Gallocyanin stain and another three specimens were processed to be studied by Golgicox method. The ultrastructural study for the cells of the red nucleus was done by transmission electron microscope. By using Gallocyanin stain, the red nucleus appeared as a circumscribed mass of cells. The caudal magnocellular part was composed mainly of large neurons and few medium and small sized neurons. The rostral parvocellular part consisted mainly of medium and small sized neurons. The cellular content of Nissl granules increased gradually from the newly born age up to the adult stage. In the aged group of animals, the cells of the red nucleus appeared to be lightly stained as compared to the adult animals indicating loss of Nissl granules. Golgi stain revealed that the caudal magnocellular part of the red nucleus was formed of different types of cells [multipolar, pyramidal and fusiform cells]. Their nerve processes showed gradual increase in the length and branching with the progress of age up to the adult stage. In the aged group of animals, these neurons showed a decrease in the extension of the nerve processes as compared to the adult group. The ultrastructural study of the caudal magnocellular part of the red nucleus in the adult animals revealed that the large neurons were characterized by the presence of rounded nucleus while the medium sized neurons had an invaginated nucleus. The cytoplasm of these cells was rich with ribosomes, rough endoplasmic reticulum and mitochondria. Several types of axosomatic synaptic terminals appeared to be present. In the aged animals, the ultrastructural study of these cells showed marked decrease in the amount of ribosomes and rough endoplasmic reticulum as compared to the adult animals. There was also accumulation of lipofuscin granules in their cytoplasm. It was concluded from this study that during the development of the red nucleus, its constituent neurons showed a progressive increase in their content of Nissil granules from the newly born age up to the adult stage. Their nerve processes also showed increase in the extension and branching. The wide variety of synaptic terminals with rubral neurons indicated the presence of several sources involved in the integration of descending motor information. In the aged animals, the rubral neurons showed several degenerative changes that could lead to impairment of motor activities

Comparison of MR Findings and Clinical Features according to Underlying Disease in Metabolic Encephalopathy

PURPOSE: Metabolic encephalopathy is not an infrequent condition. However it is very difficult to diagnose and treat because of its various causes and clinical manifestations. Our purpose was to clarify the cause of metabolic encephalopathy by evaluation of MR findings and clinical features. METHODS: We reviewed MR images and clinical features for 25 patients with metabolic encephalopathy who showed abnormal signal changes on the MR images with neurologic deterioration. RESULTS: The 25 patients had underlying diseases such as chronic liver disease (n=16) or renal failure (n=9). The MR findings showed significant differences in the involved sites according to the underlying disease. In 10 of the 16 patients with liver disease, corpus callosal involvement was observed. Red nucleus involvement was seen in 6 patients, dentate nucleus involvement in 5 patients. These lesions were seen to have a high signal intensity on the diffusion weighted image. Contrary to liver disease, encephalopathy with renal disease showed typical central pontine myelinolysis in 6 of the 9 patients and a relatively benign clinical course. CONCLUSION: Our results showed that the typically involved site and clinical manifestations depended on the underlying disease. We think that involvement of the corpus callosum, the red nucleus, and the dentate nucleus is a typical pattern of injury in metabolic encephalopathy with chronic liver disease and that these findings will be helpful for diagnosing and treating metabolic encephalopathy.

Two Cases of Methyl Bromide Intoxication with Seizures and Altered Mental State / 대한간질학회지

Methyl bromide is presently used as a fumigant for insects in soil, grains or fruit in storage or transport. It is a neurotoxic agent and has been responsible a number of deaths or acute poisonings among occupationally exposed persons. We report 2 patients, who had worked fumigation warehouse, presented with seizures and altered mental state. The serum concentrations of bromide were elevated 32.9 and 42.5 mg/l, respectively. Brain MRI showed bilateral symmetric high signal intensities in the splenium of corpus callosum, the globus pallidus, the quadrigeminal plate, the periaqueductal gray matter, the red nucleus, the substantia nigra, the medial lemniscus, the pontine tegmentum, the dentate nucleus, and the medulla. There was no brain lesion in the other patient. Appropriate and supervised handling of the chemical and regular education to workers are important to avoid the risk of methyl bromide poisoning.

Errores neurorradiológicos frecuentes en TC y RM / Frequent neuroradiological misinterpretations in CT and MR

Se presenta una revisión de las variantes anatómicas normales más frecuentes de ver en cráneo, cerebro y espacios de líquido cefalorraquídeo, que pueden ser malinterpretradas como hallazgos patológicos llevando a la realización de estudios más complejos e innecesarios. En la mayoría de los ejemplos, las variantes anatómicas son solo visibles en TC y en otros casos son exclusivas de RM. El propósito de esta revisión es conocer las variantes más frecuentemente observadas en imágenes de RM y TC con el fin de obtener un diagnóstico acertado evitando la realización de estudios posteriores innecesarios que solo llevan a aumentar los costos en salud de nuestros pacientes.

Immunocytochemical Studies of Calbindin D-28k and Parvalbumin-Containing GABAergic Neurons in the Midbrain of the Cat / 체질인류학회지

This study was carried out to investigate the morphology, distribution and co-localization of calbindin D-28k and parvalbumin-containing GABAergic cells in the midbrain of the cat. The results obtain by immunocytochemical observation were as follows : 1. Calcium binding protein calbindin D-28k and parvalbumin immunoreactive neurons were mainly found in the red nucleus, substantia nigra, oculomotor nucleus and locus ceruleus of the cat midbrain. 2. Parvalbumin immunoreactive cells in the red nucleus were more than twice in number compared to the calbindin D-28k immunoreactive cells. 3. Calbindin immunoreactive cells in the substans nigr were more than twice in number compared to the parvalbumin immunoreactive cells. 4. Double labelled immunocytochemical study revealed that parvalbumin and GABA were colocalized neurons in the same cells of the transverse section of the midbrain. 5. Calbindin D-28k and parvalbumin-immunoreactive cells were round, oval, spindle or polygonal in shape and were 15~20 micrometer in diameter. Positive neurons displayed unipolar, bipolar, or multipolar feature.

Brain MRI Findings of the Olivopontocerebellar Atrophy

PURPOSE: To demonstrate the MRI findings of olivopontocerebellar atrophy. MATERIALS AND METHODS: We retrospectively reviewed the MRI findings of eight patients who had been diagnosed by clinical manifestation and the peculiar pattern of atrophy and signal change on MRI. RESULTS: Seven patients had an atrophy of the olive, pons and cerebellum and increased signal change of the transverse pontine fiber, median raphe and middle cerebellar peduncle on T2WI. Of these, six patients had severe atrophy of the olive, pons and cerebellum and decreased signal change of the basal ganglia, red nucleus, substantia nigra or dentate nucleus on T2WI. Additionally, four of six patients had a cerebral atrophy. Except one patient who had an urinary incontinence, these 5 patients had not been associated with extrapyramidal or autonomic symptom. The other patient with relatively short duration of the disease had only cerebellar atrophy without signal change on T2WI . CONCLUSION: With progressing of the olivopontocerebellar atrophy, cerebral atrophy and decreased signal change of the basal ganglia, red nucleus, substantia nigra or dentate nucleus on T2WI is combined. Thus, MRI is essential in establishing the diagnosis and evaluating the severity of olivopontocerebellar atrophy.

Characteristics of Motor Evoked Potentials by Pyramidal and Extrapyramidal Systems in Rats / 대한정형외과연구학회지

PURPOSE: Electrophysiologically assess conduction pathways of the pyramidal and extrapyramidal systems in rats and predict the pathways involved in spinal cord injuries. METHOD: The motor area of the cerebral cortex, medullary reticular nucleus, lateral vestibular nucleus, and red nucleus of adult Sprague-Dawley rats were stimulated with microelectrodes. Laminectomies were performed at the C6, T10 and L2 cord level. Field potentials evoked by stimulation of the cerebral cortex and the three motor nuclei were recorded with a glass microelectrode of 1.5~2.5 Mohm filled with 0.2M NaCl. To construct a cross-sectional map of field potentials, recording was made in 7 tracks equally spaced across the spinal cord. In each track, field potentials were recorded at seven equally spaced points from the ventral to dorsal cord. RESULT: Stimulation of the cerebral motor cortex evoked 5 wanes, such as P1, P2, P3, P4, P5. P1 was monitored mainly in the bilateral dorsal half of the spinal cord and other wades mainly in the ventral half of the spinal cord. With lateral vestibular nucleus stimulation, 1 or 2 short duration biphasic waves followed by a longer duration positive wave were monitored mainly in the ipsilateral ventrolateral funiculus of the cord. Field potentials produced by stimulating the medullary reticular nucleus were shown mainly in the ventromedial funiculus, and their latencies were longer than those from the vestibular nucleus stimulation. Field potentials generated by the stimulation of the red nucleus were monitored mainly in the dorsolateral funiculus. CONCLUSION: motor evoked potential is clinically useful to evaluate the descending pathways of the spinal cord.

The Studies on Central Neural Axis to Innervate Rat Digastric Muscle / 대한해부학회지

The present study has been performed to investigate the neural axis of rat digastric muscle using viral tracer, pseudorabies virus. The upper nuclei to innervate digastric muscle were in accumbens nucleus, agran-ular insular cortex, central nucleus of amygaloid, lateral septal nucleus, frontal cortex, and subfornical organ etc, in telencephalon ; arcuate hypothalamic nucleus, lateral hypot-halamic area, medial preoptic nucleus, bed nucleus of stria terminalis, dorsomedial hypot-halamic nucleus, suprachiasmatic nucleus, paraventricular nucleus, and retrochiasmatic area etc, in diencephalon ; nucleus Darkschewitsch, interstitial nucleus of the medial logitudinal fasciculus, parabrachial nucleus, locus ceruleus, Kolliker-Fuse nucleus, trigeminal mesencephalic nucleus, red nucleus, substantia nigra, nucleus of posterior commissure, Edinger-Westphal nucleus, and dorsal raphe nucleus etc, in mesencephalon ; giganto-cellular reticular nucleus, raphe magnus nucleus, raphe pallidus nucleus, raphe obscuous nucleus, nucleus of solitary tracts, lateral reticular nucleus, parvocellular reticular nucleus, area postrema, facial nucleus, pontine reticular nucleus, pontine nucleus of trigeminal nerve and spinal nucleus of trigeminal nerve etc, in rhombencephalon. There are significant difference of numbers of PRV-Ba immunoreactive cells between right and left sides of brain in almost nuclei[P< 0.05]. But PRV-Ba immunoreactive cells were observed only ipsilaterally in accessory trigeminal motor nucleus, accessory facial nucleus and agranular insular cortex. Frontal cortex was the only area which were shown contralateral immunoreactivity. The results of this study provide anatomical support that both the cranial and caudal bellies are innervated by the same upper nuclei. The results also support the suggestion that the lower nuclei of digastric muscle, accessory trigeminal motor nucleus and accessory facial nucleus consist of somatotopic motor complex.

A Case of Midbrain Infarction Presenting with Dysarthria

The common causal lesions of pure dysarthria syndrome were known as anterior or posterior internal capsule, genu of internal capsule, adjacent corona radiata, or pons. And there are a few reports showed that bilateral small thalamic infarctions or paravermal cerebellar infarction also caused pure dysarthria. The rostral cerebellum, especially paravermal region is thought to have a major role in coordination of speech. The paravermal region is Intimately connected to caudal red nucleus. We report a patient with acute dysarthria and minlmal contralateral limb ataxia, in whom the causal lesion was in caudal red nucleus and superior part of decussation of brachium conjunctivum.

Claude Syndrome in Midbrain Infraction

Claude syndrome is a well known midbrain syndrome which is characterized by ipsilateral oculomotor nerve palsy and contralateral cerebellar ataxia by the lesion of the red nucleus. Although this syndrome was reported as early as in 1924 by Claude, only a few cases have been reported. Moreover, the midbrain infarction as a cause of Claude syndrome has quite rarely been described. Firstly, we report a 61-year-old patient with partial oculomotor nerve palsy and contralateral cerebellar ataxia who demonstrated an infarction just caudal to the red nucleus on MRI. Secondly, we also discuss the probable vertical fascicular arrangement of the oculomotor nerve in the midbrain.

Unilateral ataxia following herpes zoster of spinal C4 segment.

Focal lesions of central nervous system are extremely rare following cutaneous herpes zoster. A 55 year old male developed cerebellar speech, right sided ataxia and intention tremor, three weeks after herpes zoster of right spinal C4 segment. Clinical examination and investigations confirmed a focal vascular lesion in the midbrain suggestive of granulomatous angiitis which can cause focal neurological defect after herpes zoster.

A Case of Suspected Hallervorden-Spatz Disease

Hallervorden-Spatz disease is a rare, autosomal recessive disorder of mainly early childhood which is characterized by pigmentary degeneration of the globus pallidus, substantia nigra, and red nucleus. Clinically it manifests various symptoms and signs of extrapyramidal and pyramidal involvement. Authors report a 28-year-old female patient with suspected Hallervorden-Spatz disease in the aspects of clinical and MRI findings suggesting metal deposition in the globus pallidus, substantia nigra, and red nucleus on both side.