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PubMed1986

Aphasia associated with verified subcortical lesions: three case reports.

Aphasia classically has been described as an acquired impairment of language behavior subsequent to cortical brain injury to the dominant hemisphere. Traditionally, lesions in the internal capsule have been described as resulting in pure motor deficits, which may be accompanied by dysarthria without aphasia. Only recently has the literature suggested that lesions in the putamen and internal capsule may result in aphasia. We describe three clinical cases in which aphasia resulted from left subcortical lesions. The lesions were demonstrated using computed tomographic (CT) scan; language deficits were measured objectively using the Porch Index of Communicative Ability (PICA). Two of the three patients experienced excellent recovery of language skills, suggesting that subcortical lesions may have a more favorable prognosis in recovery from aphasia than do cortical lesions. The encouraging recovery may be related to fiber pathway disruption rather than cortical destruction.

Adult↗
PubMed1998

Territories of the perforating (lenticulostriate) branches of the middle cerebral artery.

The territories of the central branches of the middle cerebral artery (MCA) were examined in 21 injected human brains. It was noted that these central arteries supplied: the caudate nucleus (dorsolateral half of the rostral part of its head; the entire caudal part of the head; the body and rostral portion of the tail in some cases), the putamen (dorsolateral part of its rostral portion, the remainder of the putamen, except the most caudal part occasionally), the globus pallidus (the entire lateral segment, except the ventrorostral and, sometimes, the most caudal part), the basal forebrain (lateral parts of the basal nucleus of Meynert and the nucleus of the diagonal band, as well as fiber bundles in this region), the internal capsule (dorsal and ventrocaudal part of the anterior limb, dorsal part of the genu, dorsal and ventrorostral part of the posterior limb), the corona radiata (a narrow strip close to the internal capsule) and the cerebral cortex (the caudal orbitofrontal cortex occasionally). The presented data may have certain neuroradiologic, neurologic and neurosurgical significance.

Adult↗
PubMed1999

Electrophysiological versus image-based targeting in the posteroventral pallidotomy.

OBJECTIVE: To study the functional accuracy of stereotactic targeting for the posteroventral pallidotomy (PVP), comparing targets chosen on magnetic resonance images (MRI), and fused MRI to computed tomographic (CT) images, with electrophysiologically refined anatomical targets. METHDOS AND MATERIALS: For each of the 10 pallidotomies three sets of targets were collected, beginning with the MRI targets. The second target set was measured on images generated by nonlinear volumetric fusion of MRI images with CT using Image Fusion (Radionics, Inc.). The anatomical target site was then determined electrophysiologically with intraoperative microelectrode recording and macroelectrode stimulation guidance. RESULTS: Magnetic resonance imaging or MRI-CT fused images alone would not have been sufficiently accurate to preclude visual or motor complications in the posteroventral pallidotomy, based on our target located within 1 mm of the optic tract and within 2 mm of the internal capsule. In 2 of the 10 cases of either MRI or fused images, the targets were dangerously close to the optic tract. Two of 10 of the fused targets were within the internal capsule. The fusion of MRI with CT did not functionally improve the targeting accuracy of MRI, since the means of the MRI targets and the fused targets were statistically the same. Individually, however, the MRI target was different from the fused target in each case by an average radial distance of 3.5 +/- 2.3 mm, but such corrections were not statistically or surgically significant. CONCLUSIONS: Image-based targeting including MRI or fused MRI-CT data may not be sufficiently accurate to prevent capsular or visual deficits in the posteroventral pallidotomy, necessitating electrophysiological refinement. In this report, the functional accuracy of MRI was not improved by fusion with CT.

Analysis of Variance↗
PubMedDate not supplied

High signal regions in normal white matter shown by heavily T2-weighted CSF nulled IR sequences.

Inversion recovery (IR) sequences with an inversion time (TI) designed to markedly reduce or null the signal from CSF (TI of approximately 2,100 ms at 1.0 T) and a very long echo time (TE) of 240 ms were used to image the brain of two normal adult volunteers, one 34-year-old man with an intrinsic tumor, and one 3-month-old infant with an infarct. Using these very heavily T2-weighted pulse sequences, adult gray and white matter showed similar signal intensity in many areas of the brain, but normal white matter in regions of the centrum semiovale, posterior internal capsule, parietopontile tract, occipitothalamic radiation, and brain stem showed a much higher signal intensity than surrounding gray or white matter. The infant displayed a low signal intensity in myelinated regions in the internal capsule and occipitothalamic radiation and a high signal in unmyelinated white matter. In many of the images there were strong similarities to the distribution of high signal within white matter seen with pulsed gradient spin echo sequences (TE 130 ms) designed to demonstrate effects due to anisotropic diffusion. Arguments are advanced to support the view that the high signal intensity in white matter tracts is due to one or more long T2 components that may be associated with unmyelinated or sparsely myelinated fibres within white matter. The resemblance to diffusion weighted images may reflect the fact that both employ long TEs and both produce a low signal from CSF. If myelin possessed a different susceptibility from axoplasm so that magnetic field gradients were generated around nerve fibres when their orientation was not parallel to B0, diffusion of water might then produce the observed dependence on fibre direction. The high signal regions in white matter are a potential source of confusion in image interpretation, and measurements of T2 in white matter need to be made with these regional variations in mind. The concept of normal appearing white matter also needs to be applied with a knowledge of these differences. The IR sequences used in this study provide a very high T2 dependence with a low signal from CSF and may be useful for detecting disease in the CNS of adults and children.

Adult↗
PubMed2004

Factors affecting the angiographic recanalization and early clinical improvement in middle cerebral artery territory infarction after thrombolysis.

BACKGROUND: Factors affecting the angiographic recanalization (AR) and clinical improvement (CI) still remain unclear in patients receiving thrombolytic therapy. OBJECTIVES: To elucidate factors related to AR and early CI in patients with middle cerebral artery (MCA) or internal carotid artery (ICA) occlusion. DESIGNS: Retrospective study. SETTING: Department of Neurology, Asan Medical Center, Seoul, South Korea. PATIENTS: We studied 42 patients who (1) underwent diffusion-weighted magnetic resonance (MR) imaging and MR angiography within 6 hours after onset, (2) had MCA territory infarction, (3) had nonvisualization of the MCA or the ICA on initial MR angiography, (4) were treated with thrombolytics, and (5) underwent follow-up MR imaging and MR angiography at day 2 or 3. RESULTS: Successful AR and CI were achieved in 31 and 16 patients, respectively. Angiographic recanalization was related to CI (P<.01), lower follow-up National Institutes of Health Stroke Scale scores (P<.05), the absence of a dominant ipsilateral posterior cerebral artery (P<.01) on initial MR angiography, and the sparing of the internal capsule on both initial (P<.05) and follow-up (P<.01) MR imaging. Clinical improvement was associated with the absence of ICA (vs MCA) flow signals (P<.05), the sparing of the internal capsule (P<.01), and marginally, with the infarct volume change (P = .06). CONCLUSIONS: In patients with MCA or ICA occlusion, CI after thrombolysis is related to the AR and the sparing of the critical motor pathway. The presence of a dominant ipsilateral posterior cerebral artery may predict poor AR after thrombolysis.

Aged↗
PubMed1995

Diencephalic changes in traumatic brain injury: relationship to sensory perceptual function.

Magnetic resonance (MR) imaging scans of 33 traumatically brain-injured (TBI) patients were compared quantitatively to MR scans of controls matched for age and gender. Quantitative estimates of thalamic, internal capsule, and third ventricle morphology were obtained in each TBI patient. Comparisons were made to normal control subjects and revealed significant reduction in thalamic volume with corresponding increase in third ventricle. Measurements of internal capsule reflected nonsignificant changes. Significant correlations were observed between sensory-perceptual functioning, as measured by the Reitan-Kløve Sensory-Perceptual Exam, and thalamic volume in TBI patients. A decrease in thalamic volume was associated with an increase in sensory-perceptual errors.

Adolescent↗
PubMed1998

Anatomical structures in the Leksell pallidotomy target.

OBJECTIVE: Because interruption of pallidal outflow signals by pallidotomy is believed to play an important role in the motor improvement in Parkinson's disease, the anatomical relationship of the two major pallidofugal tracts, namely the ansa lenticularis (AL) and the fasciculus lenticularis (FL) to the Leksell pallidotomy target (LPT) were studied. METHODS: Magnetic resonance (MR) scans of 20 patients with Parkinson's disease were studied. The scans were obtained in the inversion recovery and fast spin echo sequences and viewed in the reverse video mode. RESULTS: The pallidofugal tracts appeared as bands of high intensity on MR scan. FL was wide and extended from the posterior half of the globus pallidus interna (GPi) medially into the internal capsule. AL was narrow, parallel and posterior to the anterior commissure, parallel to and 3 mm above the optic tract, and just beneath the FL. The part of the FL immediately lateral to the internal capsule overlapped the lateral end of the AL. The center of this overlapping area was termed the 'operlapping point' (OP). In all cases, the OP was within the range of LPT. CONCLUSION: It is concluded that the structures in the LPT are FL and AL; and therefore, this procedure could also be known as 'fasciculoansatomy'.

Aged↗
PubMed1976

The nigrostriatal projection in the cat. Part 1. Silver impregnation study.

The course and destination of the degenerating nigrostriatal fibers were studied by selective silver impregnation methods in 37 cats with unilateral lesions in the substantia nigra. The nigrostriatal fibers ascend along the dorsomedial border of the substantia nigra to the prerubral area; they proceed for a short distance through the lateral hypothalamus, enter the medial part of the internal capsule and run in a dorsorostral direction to reach the head of the caudate nucleus and the rostral portion of the putamen. A smaller number of degenerating fibers obliquely cross the peduncular part of the internal capsule and traverse the entopeduncular nucleus and the pallidum to terminate in the central and caudal portions of the putamen. Some features of the topical distribution of the nigrostriatal tract are described. Apparently, the more anterior part of the pars compacta sends axons primarily to the head of the caudate nucleus and to the most rostral putamen. The most medially situated nigral neurons project to the fundus striati. The posteromedial cell groups of the pars compacta innervate primarily the central putamen and the caudal part of the caudate nucleus. The projection of the lateral cell group of the posterior zona compacta to the caudal putamen is sparser than from the other nigral groups, suggesting that a part of them has another destination, possibly lower in the neuraxis. The contribution of the pars of reticulata to the nigrostriatal connections seems to be modest, according to the small number of neurons; they project to the lateral caudate and putamen. Thus, the ascending nigrostriatal fibers mirror the distribution of the descending striatonigral fibers. No convincing evidence for the existence of a nigroentopeduncular and nigropallidal projection was found.

Animals↗
PubMed2004

Polyurethane vascular grafts with thorough porosity: does an internal or an external membrane wrapping improve their in vivo blood compatibility and biofunctionality?

Using a freeze-drying multiple-step technique, porous polyurethane vascular grafts 1.5 mm in diameter with different internal and external surface characteristics were fabricated: Type A: with thorough porosity, Type B: with internal membrane wrapping and Type C: with external membrane wrapping. One centimeter long tubes of each three types of grafts were implanted into the infra-renal abdominal aorta of rats for periods of 2, 4, 8 weeks. All the grafts were patent at harvesting. At the end of 2 weeks postimplantation, the endothelial cells layer developed inside the grafts about 1.2 mm apart from either the distal anastomosis side or both the distal and proximal anastomoses. They spreaded to the middle part of the one cm-long graft at 4 weeks. The luminal surfaces were entirely covered by a layer of endothelial cells at 8 weeks. Smooth muscle cells also migrated underneath the endothelial cell layer through the inner surface from the anastomosis and grew into the porous wall to generate a biocomposite blood conduit. Type B grafts with an internal membrane wrapping, developed a thicker, easy to lift intima after all the durations of implantation because the internal capsule was poorly anchored to the device. It is therefore of paramount importance that a porous structure is exposed to the blood flow to permit an adequate healing together with a good anchorage of the internal capsule.

Animals↗
PubMed1997

GDNF is a trophic factor for adult rat corticospinal neurons and promotes their long-term survival after axotomy in vivo.

Glial cell line-derived neurotrophic factor (GDNF) is a trophic factor for several neuronal populations involved in motor control. The present study evaluates the trophic actions of GDNF on corticospinal neurons, an important central nervous system motor projection into the spinal cord. Death of spinal motoneurons and corticospinal neurons is observed in the neurodegenerative disease amyotrophic lateral sclerosis. Axotomy of adult rat corticospinal neurons at internal capsule levels induces half of them to die, and the surviving population displays severe atrophy. To examine the trophic effects of GDNF on corticospinal neurons, Fast Blue-labelled corticospinal neurons were stereotaxically axotomized at internal capsule levels and GDNF was infused intracortically to lesioned corticospinal neurons at total doses of 2, 4, 10, 20, 40, 100 and 300 microg for 7 days. GDNF prevented axotomy-induced death of corticospinal neurons at doses between 2 and 40 microg and abolished or attenuated their atrophy at all doses examined. In addition, treatment with 8 microg GDNF for the first 2 weeks after axotomy resulted in the long-term survival of corticospinal neurons for 42 days. With regard to the development of treatment strategies for upper motoneuron degeneration in amyotrophic lateral sclerosis, application of GDNF via the cerebrospinal fluid may be more relevant than intracortical delivery as its diffusion within the brain parenchyma is limited. Intraventricular as well as intracisternal infusion of GDNF (300 microg over 7 days) completely prevented corticospinal neuron death. These results show that GDNF promotes the long-term survival of corticospinal neurons and has a positive effect on their size in vivo. Furthermore, the survival-promoting effect of GDNF on corticospinal neurons after delivery via cerebrospinal fluid has important clinical implications for potential treatment of the upper motoneuron degeneration seen in amyotrophic lateral sclerosis.

Animals↗
PubMed1990

Capsular hypesthetic ataxic hemiparesis.

Twenty-three patients with hypesthetic ataxic hemiparesis underwent computed tomography or magnetic resonance imaging. Twenty-two patients had infarcts of lacunar or slightly larger size in the contralateral posterior limb of the internal capsule. In 15 patients the infarct extended superiorly into the adjacent paraventricular region, and in seven it extended into the lateral thalmus. In eight patients the infarct was limited to the posterior limb of the internal capsule, and in only two patients was an ipsilateral to capsular pontine lacune found. Despite a location similar to that of pure motor and pure sensory lacunar stroke, hypesthetic ataxic hemiparesis correlates with larger infarcts, most often located in the posterior medial superior territory of the anterior choroidal artery. Some infarcts appeared to be localized immediately posterolateral to this region, in the posterior cerebral artery territory. The presence and extent of infarction is better detected by the addition of magnetic resonance imaging to computed tomography.

Adult↗
PubMed1996

CT-target determination in postero-ventral pallidotomy: a universal method. Technical note.

Stereotactic targeting of the postero-ventral pallidum (PVP) presents special challenges to the surgeon 1) The target is in intimate relation to the optic tract and the internal capsule. 2) Proper angulation of the trajectory is crucial to achieve optimal effects given the long craniocaudal extension of the PVP. 3) The PVP is difficult to identify on computerized tomography (CT): the border between the internal capsule and the pallidum is usually not apparent. Potential sources of error in target determination include: - angulation of the scanning plane in relation to the intercommissural plane; - projection of the reference points (anterior commissure/posterior commissure [AC/PC]) results in the foreshortened intercommissural line, affecting the Y co-ordinate; - small tilts between the CT gantry and the stereotactic frame affect determination of the X and Z co-ordinates. Correction of these sources of error is done with basic trigonometric algorithms. The authors have developed a rapid method of stereotactic co-ordinate calculation which avoids the need to perform error-prone calculations under the pressure of operating room conditions. 1) The frame is applied with its basal plane corresponding roughly to the orbito-meatal line. 2) Thin CT slices (2 mm increments) are obtained through the area of interest and the slices are printed. 3) The major reference points (Foramen of Monro, AC, PC) are identified and marked. The PC point is projected onto the film containing AC (or viceversa if the PC slice is caudal to AC). 4) The intercommissural distance is measured, and the true length is obtained from a correction graph. The Y co-ordinate is then calculated as 1/2 ICL + 2 mm [towards AC]. 5) The slice corresponding to the target [Z co-ordinate] is obtained from a correction graph that takes into consideration the gap [number of slices] between AC and PC. 6) The X co-ordinate is placed 20 to 22 mm from midline. A graph that takes into consideration the coronal tilt of the stereotactic frame in relation to the CT gantry allows for final corrections of the X and Z co-ordinates. This step-by-step simple method of co-ordinate calculation can be used with any CT-compatible stereotactic frame.

Brain Mapping↗
PubMed2004

Experimental cerebral hypoperfusion induces white matter injury and microglial activation in the rat brain.

Though cerebral white matter injury is a frequently described phenomenon in aging and dementia, the cause of white matter lesions has not been conclusively determined. Since the lesions are often associated with cerebrovascular risk factors, ischemia emerges as a potential condition for the development of white matter injury. In the present study, we induced experimental cerebral hypoperfusion by permanent, bilateral occlusion of the common carotid arteries of rats (n=6). A sham-operated group served as control (n=6). Thirteen weeks after the onset of occlusion, markers for astrocytes, microglia, and myelin were found to be labeled by means of immunocytochemistry in the corpus callosum, the internal capsule, and the optic tract. The ultrastructural integrity and oligodendrocyte density in the optic tract were investigated by electron microscopy. Quantitative analysis revealed that chronic cerebral hypoperfusion caused mild astrogliosis in the corpus callosum and the internal capsule, while astrocytic disintegration in the optic tract increased by 50%. Further, a ten-fold increase in microglial activation and a nearly doubled oligodendrocyte density were measured in the optic tract of the hypoperfused rats as compared with the controls. Finally, vacuolization and irregular myelin sheaths were observed at the ultrastructural level in the optic tract. In summary, the rat optic tract appears to be particularly vulnerable to ischemia, probably because of the rat brain's angioarchitecture. Since the detected glial changes correspond with those reported in vascular and Alzheimer dementia, this model of cerebral hypoperfusion may serve to characterize the causal relationship between ischemia and white matter damage.

Analysis of Variance↗
PubMed1974

Distribution of microglial clusters in the brain after head injury.

The brains of 12 cases of head injury have been submitted to gross pathological study and microscopic examination by the Weil-Davenport method, with special reference to the corpus callosum, internal capsules, and brain-stem in each case. Microglial clusters were observed in 11 out of 12 cases, the most common sites for these being the corpus callosum ipsilateral to the external applied force and the internal capsule and brain-stem contralateral to this applied force. This pattern of distribution of lesions remained constant in all cases. The nature, aetiology, and distribution of these lesions is discussed and it is concluded that such lesions arise from the formation of definite patterns of shearing forces which snap axons. These forces arise from the rotational movements set up within the skull resulting from the relative delay of movement of the brain with respect to the skull and dura mater.

Brain↗
PubMed1984

Adult form of Leigh's disease: a clinico pathological case with CT scan examination.

The clinical and pathological findings of a 31-year-old woman, in whom the diagnosis of Leigh's disease was made, are reported. CT scan examination with contrast enhancement showed symmetrical areas of low density, in both thalami, anterior limbs of internal capsules and corpus callosum. Longstanding chronic lesions involved the optic chiasma and the cerebral peduncles and consisted of myelin loss, status spongiosus, astrocytic gliosis and marked capillary proliferation. The neurons were spared. In the basal ganglia, internal capsules and corpus callosum, these lesions were more recent and consisted of focal necrosis, perivascular oedema and few lymphocytic perivascular cuffings.

Adult↗
PubMed1984

Ataxic hemiparesis: further CT confirmation of an old localizing hypothesis.

4 cases of ataxic hemiparesis syndrome are supported by CT proof of a lesion confined to the posterior and superior part of the internal capsule, near the corona radiata. The site of lesion is usually held to be the basis pontis and rostral midbrain. We intend to furnish further evidence in support of an old hypothesis incriminating the corona radiata-internal capsule.

Aged↗
PubMed2005

Local tissue anisotropy decreases in cerebellopetal fibers and pyramidal tract in multiple system atrophy.

BACKGROUND: One of the cardinal features in multiple system atrophy (MSA) is the white matter pathology: loss of myelin, astrocytosis, and glial cytoplasmic inclusions. The pathological changes of tissue microstructure can modify the diffusion behavior of water molecules, which can be assessed by diffusion tensor imaging (DTI). OBJECTIVES: To explore the hypothesis of white matter degeneration in MSA. METHODS: We studied 11 patients with clinically probable MSA and 10 age-matched controls. DTI was performed in both groups to measure fractional anisotropy (FA) in various regions of interest: the inferior cerebellar peduncle (ICP), middle cerebellar peduncle (MCP), superior cerebellar peduncle (SCP), basis pontis, internal capsule, and corpus callosum. RESULTS: FA values in SCP and corpus callosum showed no significant difference between the MSA group and controls. By contrast, FA values decreased in the MSA group in the MCP, basis pontis and internal capsule. In addition, FA values in the MCP were negatively correlated with ataxia severity in the MSA group. CONCLUSION: The areas showing decreased tissue anisotropy in DTI corresponded well with pathologically vulnerable areas in MSA. In addition, the local tissue anisotropy of MCP decreased in accordance with functional disability. These observations implied that DTI is a feasible method for in vivo evaluation of the white matter pathology in MSA.

Aged↗
PubMed2005

Lesions in the brains of three cattle resembling the lesions of enterotoxaemia in lambs.

CASE HISTORY: A 3-month-old female Angus calf was found dead, and two adult Friesian dairy cows died soon after developing nervous signs. PATHOLOGICAL FINDINGS: Grossly, bilateral and mostly symmetrical areas of haemorrhage were evident that mainly involved areas of grey matter in the brainstem from the level of the caudal colliculi to the thalamus and, in one, the internal capsule and caudate nucleus. In the occipital and caudal parietal cortex, there was extensive oedema of white matter. Histologically, in addition to haemorrhage, there was protein-rich oedema around arterioles and venules in the cerebrum, hippocampus, internal capsule, thalamus, midbrain, dorsal medulla, and central cerebellar and cerebellar folial white matter. The calf 's brain had bilateral and symmetrical oedema and necrosis affecting several brainstem nuclei and the occipital grey matter overlying areas of oedema of the corona radiata. DIAGNOSIS: Although the cause was not established, the perivascular lesions resembled those produced in calves by the intravenous administration of epsilon toxin. CLINICAL RELEVANCE: It is possible that epsilon toxin-induced enterotoxaemia occurs naturally in cattle, and where bilateral haemorrhage is recognised in the brains of cattle, small intestinal contents should be collected for analysis of epsilon toxin.

Acute Disease↗