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Biomedical subjects

B Verbeeten

Publications and source records attributed to B Verbeeten.

At least 37 records · Page 2Linked to original sources
PubMed1995

Non-decussating retinal-fugal fibre syndrome. An inborn achiasmatic malformation associated with visuotopic misrouting, visual evoked potential ipsilateral asymmetry and nystagmus.

We report a newly identified syndrome in which nasal retinal fibres fail to decussate due to the inborn absence of an optic chiasm. Visual evoked potential (VEP) assessment and neuro-opththalmic evaluation in two unrelated, non-albino children revealed the unusual visual pathway anomaly in the form of misrouted retinal-fugal projections. Monocular VEP responses across the occiput, regardless of stimulus mode (full- or partial-field pattern onset, pattern reversal, luminance flash or high temporal frequency luminance flicker) showed unequivocal evidence of pathological VEP ipsilateral asymmetry. Marked attenuation of primary visual evoked responses from the occiput contralateral to the eye of stimulation, indicative of aberrant contralateral retinal-fugal projections, was confirmed by MRI which depicted the remarkable achiasmatic condition. MRIs and neurological evaluation also confirmed the absence of accompanying congenital or acquired brain malformations or anomalies. Ophthalmic evaluation revealed that both achiasmatic children had reduced distance acuity for age, alternating esotropia, torticollis, head tremor and ocular motor instability; visual fields were normal. Eye movements were also monitored and indicated congenital nystagmus waveforms in the horizontal plane; see-saw nystagmus was observed in the the horizontal plane; see-saw nystagmus was observed in the vertical and torsional planes. The age range of the two children during evaluation and follow-up, over a 6-year period, was about 4-15 years. Comparisons of VEP responses from age-matched normal, albino and idiopathic congenital nystagmus controls, recorded under the same VEP test conditions, were also performed. In contrast to the achiasmatic ipsilateral inter-ocular asymmetry, the albinos showed the expected monocular VEP topography pattern of contralateral asymmetry. Also as expected, VEP profiles from the normal controls and those with congenital nystagmus, evinced no aberrant asymmetry patterns. In general, the results indicate that the VEP misrouting protocol is indispensable for the non-invasive electrophysiological detection and differential diagnosis of optic pathway mutations and may well identify individuals with purported idiopathic congenital nystagmus or albinism that are, in fact, achiasmatic.

Adolescent↗
PubMed1995

Trigeminal neuropathy: evaluation with MR imaging.

Neuropathy of the trigeminal nerve can involve its full course, from its nuclei in the brain stem to its peripheral branches. The nerve can be divided into four segments--brain stem, cistern, the Meckel cave and cavernous sinus, and extracranial--and consideration of the pathologic entities by these locations simplifies the differential diagnosis. Multiple sclerosis, infarct, and glioma are the most common abnormalities in the brain stem leading to trigeminal neuropathy. The most common cisternal cause is neurovascular compression, followed by acoustic and trigeminal schwannomas, meningiomas, epidermoid cysts, lipomas, and metastases. Trigeminal neuropathy arising from the Meckel cave and cavernous sinus is frequently due to meningiomas, trigeminal schwannomas, epidermoid cysts, metastases, pituitary adenomas, and aneurysms. Malignant tumors, which may demonstrate perineural tumor spread, are the most common extracranial cause. Because the clinical findings do not permit accurate lesion localization, magnetic resonance imaging must be used to visualize the entire course of the fifth cranial nerve. The standard study should include T2-weighted images of the whole brain and high-resolution axial and coronal T1-weighted images of the skull base obtained with and without contrast material enhancement.

Adult↗
PubMed1992

Memory complaints, memory disorders and focus localization in patients with partial epilepsy.

Our study aimed at analysing effects of epileptic foci on memory function in patients with partial epilepsy. Twenty-eight patients with spontaneous memory complaints and psychometrically established memory disorders were assessed by 21-channel electroencephalography recorded both during cognitive testing and during 99mTc-HMPAO single photon emission computed tomography (SPECT). Computed tomography (CT) was performed on the same day. None of the epilepsy-related factors (seizure type, seizure frequency, type of epilepsy, age at onset of the seizures, type of antiepileptic treatment) could be related directly to severity or type of memory impairment (classified into the categories 'global', 'verbal' and 'non-verbal'). Remarkably, this study found no significant relationship between EEG focus localization and severity of measured memory impairment. Most areas with hypoperfusion on the SPECT were found in the group with global (severe) amnesia, typically with a right frontal localization. Abnormalities on CT were predominantly found in the same group, however, with a right-sided parietal localization. An unanticipated finding was that the majority of temporal CT and SPECT lesions were found in the group with relatively better memory performance.

Adult↗
PubMed1992

Focus localization in patients with partial epilepsy with 99Tcm-HMPAO SPECT under continuous surface EEG monitoring.

Our study was aimed at determining the validity of 99Tcm-HMPAO single photon emission computed tomography (SPECT) in the localization of the epileptogenic focus by correlating this diagnostic method with other auxiliary investigations such as surface EEG and X-ray transmission computed tomography (CT). Twenty-eight patients with partial epilepsy and spontaneous memory complaints were assessed with a 21-channel EEG recorded during psychometric evaluation of the memory complaints and with a 12-channel EEG during 99Tcm-HMPAO SPECT. No significant agreement was observed for total focus localization by the two EEGs, CT or SPECT. The EEGs were highly reproducible. Frontal and temporal pathology on CT resulted in frontal and temporal cold spots on SPECT on the same side in six patients. In addition, SPECT demonstrated frontal, temporal or posterior temporal-inferior parietal cold spots in nine patients without accompanying pathology on CT. It is concluded that CT and SPECT may provide complementary anatomical and functional information, respectively, to the EEG. Furthermore, SPECT may be complementary to CT in visualizing functional deficits without an anatomical correlate. The value of SPECT studies in partial epilepsy may be improved by increasing the resolution of the SPECT system and by simultaneous EEG monitoring.

Adult↗
PubMed1991

Intradiploic epidermoid cysts of the bony orbit.

Epidermoid cysts originating within the diploic space of the bony orbit are rare. The authors retrospectively studied four patients with an intradiploic epidermoid cyst of the orbital bones to investigate the clinical and the computed tomographic (CT) findings. The clinical presentation was dependent on the location of the slowly expanding epidermoid cyst. The sphenoid bone was involved in three patients and the frontal bone in one patient. Proptosis caused by intraorbital extension of the mass was the most common presenting sign. The findings on high-resolution CT scans appeared to be specific for intradiploic epidermoid cysts. The typical sclerotic margin, which is diagnostic of intradiploic epidermoid cysts, can be demonstrated by CT scans with a bone window setting.

Adolescent↗
PubMed1991

Leukoaraiosis and ventricular enlargement in patients with ischemic stroke.

We studied the relationship between ventricular size and nonspecific periventricular lucency on computed tomograms (leukoaraiosis) in 192 patients with ischemic stroke. Leukoaraiosis did not occur in 21 patients less than 50 years of age; ventricular size could not be measured in an additional 29. Leukoaraiosis was graded from 0 to 4 on a semiquantitative scale; bicaudate, frontal horn, and posterior horn indices were used as measures of ventricular size. Patients with leukoaraiosis were older (difference between means 7 years, t = 5.3, df = 140, p less than 0.0001) and had larger bicaudate indices (difference between means 0.023, t = 3.54, df = 140, p = 0.0007) than patients without leukoaraiosis. Multiple regression analysis demonstrated that the effects of age and leukoaraiosis were independent. No effect of lesion type (cortical or lacunar infarct, or both) on bicaudate index could be demonstrated. Larger values for the bicaudate index were associated with a predominantly anterior location of leukoaraiosis. The frontal horn and occipital horn indices increased with age, but we could not find an effect of leukoaraiosis on these indices.

Aged↗
PubMed1991

rCBF-SPECT in brain infarction: when does it predict outcome?

We prospectively studied 26 patients with ischemic stroke within 24 hr, after 2 wk, and after 6 mo with thallium-201-diethyldithiocarbamate single-photon emission computed tomography (SPECT) and neurologic and functional assessments. The admission flow deficits correlated with outcome. The admission and 6-mo scores correlated with clinical conditions at each time. At 2 wk, the flow deficits were smaller and did not correlate with clinical parameters. Nor did the presence or absence of hyperfixation of the radiopharmaceutical. Six months after the infarct, the flow defect had decreased in 9 of 15 patients in whom three serial scans were available, with better clinical improvement than in the remaining six whose flow deficits increased. More patients in the first group had been treated randomly with the calcium-entry blocker flunarizine. SPECT imaging of rCBF within 24 hr after stroke correlates with clinical outcome and condition, whereas rCBF imaging at 2 wk after the stroke shows no clinical correlation.

Aged↗
PubMed1990

Relation of leukoaraiosis to lesion type in stroke patients.

Nonspecific periventricular white matter lucencies on computed tomograms (leukoaraiosis) were found in 141 (38%) of 367 patients with ischemic or hemorrhagic strokes. Patients with leukoaraiosis were significantly older than those without it and were significantly more likely to have hypertension, diabetes mellitus, general vascular disease, and lacunar infarcts on computed tomograms but were less likely to have cortical infarcts. Because many of these variables may be mutually dependent, we performed a logistic regression analysis examining all clinical and computed tomographic variables. The analysis demonstrated that increasing age, lacunar infarcts, and hemorrhages were significant determinants of leukoaraiosis; cortical infarcts were also significantly, but negatively, correlated with leukoaraiosis. In patients with hemorrhages, leukoaraiosis occurred significantly more often when aneurysms or arteriovenous malformations were not demonstrated. These findings suggest that in patients with cerebrovascular disorders leukoaraiosis is associated with small-vessel disease.

Adult↗
PubMed1988

Urinary tract malakoplakia with extension into the retroperitoneum with secondary gastrointestinal involvement.

A rare case of malakoplakia of the urinary tract with diffuse retroperitoneal extension is presented. Sonographically guided cytologic puncture revealed the pathologic diagnosis. The splenic flexure of the colon and the stomach appeared to be secondarily involved in the inflammatory retroperitoneal tumor. The relative role of the various imaging modalities in defining retroperitoneal extension of the disease is illustrated, with a special reference to computed tomography and endosonography. After antimicrobial treatment and left nephrectomy, partial regression of the retroperitoneal mass was documented.

Adult↗
PubMed1988

Electromyographic and computed tomographic findings in five patients with monomelic spinal muscular atrophy.

Five patients with monomelic spinal muscular atrophy are described. Clinical features included insidious onset of wasting and weakness of one limb, lack of involvement of the cranial nerves, brain stem, pyramidal tracts and sensory system, and a stable condition over a period of 4-20 years. Clinical findings, electromyography and/or muscle biopsy were consistent with anterior horn cell lesion. Central cavities were excluded by magnetic resonance imaging studies of the spinal cord. Computed tomography of skeletal musculature and electromyography indicated more diffuse lower motor neuron involvement by revealing abnormalities in clinically unaffected muscles in 4 of the 5 patients. Myokymic discharges were found in the affected limb of 1 patient.

Adolescent↗
PubMed1986

Pseudohypertrophy of the calf following S1 radiculopathy.

Development of unilateral calf enlargement following chronic S1 radiculopathy occurred in a 39-year-old woman. Computed tomographic examination of the leg musculature showed that the calf enlargement was due to pseudohypertrophy, as the increased area in the posterior leg muscles showed a decrease in density.

Adult↗
PubMed1985

Computed tomography of the skeletal musculature in Becker-type muscular dystrophy and benign infantile spinal muscular atrophy.

Results of computed tomographic (CT) examination of the skeletal musculature in 26 patients with Becker-type muscular dystrophy (BMD) and 12 patients with benign infantile spinal muscular atrophy (BISMA) are presented. Both disorders revealed strikingly different changes that may have important clinical significance. First, in BMD, CT abnormalities consisted of areas of decreased densities, at first appearing in part of the muscle, and then gradually spreading until the whole muscle was replaced by low-density tissue. In BISMA, however, low-density lesions were scattered throughout the muscle. Second, in BMD, some muscles were preferentially affected in an early stage of the disease and others were relatively spared, whereas in BISMA, the muscles were involved more or less simultaneously. Third, an enlargement in size (hypertrophy) was frequently observed in BMD in various muscles of the legs, whereas in BISMA, this phenomenon can sometimes be noted only in the gastrocnemius muscles.

Adolescent↗
PubMed1985

Progressive multifocal leukoencephalopathy in a case of acquired immune deficiency syndrome.

The case of a 40-year-old homosexual male with A.I.D.S. (Acquired Immune Deficiency Syndrome) and P.M.L. (Progressive Multifocal Leukoencephalopathy) is described. The importance of a brain biopsy for diagnostic procedures, especially in the case of a patient with A.I.D.S. is stressed. The diagnosis P.M.L. has been made by means of light- and electronic microscopical examination, and the presence of JCV-DNA in the brain tissue has been confirmed by dot hybridization. Various antiviral treatments did not show any effect on the course of the P.M.L.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Detection of basilar artery thrombosis by CT.

A case is presented with distal basilar artery occlusion diagnosed by computed tomography (CT). The normal basilar artery imaged on plain CT scans has an attenuation value not higher than that of whole blood. If the CT attenuation value of the vessel is higher than that of blood, basilar artery occlusion is probably present. In the case presented the cause was traumatic thrombo-embolic occlusion of the basilar artery.

Adult↗
PubMed1985

Some anatomical variants and pitfalls in computed tomography of the trachea and mainstem bronchi. I. Mucoid pseudotumors.

472 computed tomographic (CT) examinations in 448 patients were reviewed for mucoid pseudotumors. In 10 patients (2%), an intraluminal density was indirectly proven to be mucous material by negative bronchoscopy and/or repeat CT. Mucoid pseudotumors can easily be differentiated from CT artifacts and from intraluminal neoplasms with extraluminal extension. Differentiation from true intraluminal neoplasmata may be difficult. No definite diagnostic criteria can be proposed since there were no true intraluminal neoplasms present in this series. Nonetheless, several characteristic radiological features of mucoid pseudotumors are discussed. When a potential mucoid pseudotumor is found in a CT examination either the CT scans in question should be repeated after vigorous coughing or an intraluminal neoplasm should be excluded by bronchoscopy. Starting from the CT examination, in the case of bronchogenic carcinoma of the central airways, the intraluminal extent of the tumor might be overestimated due to mucous material proximal to the tumor.

Adolescent↗
PubMed1985

Some anatomical variants and pitfalls in computed tomography of the trachea and mainstem bronchi. II. Compression or anatomical variants?

472 computed tomographic (CT) examinations in 448 patients were reviewed for depression of the wall of the trachea and mainstem bronchi. Depression was defined as a neutral term, not indicating pressure exerted upon the wall. Such depressions appeared to occur very frequently as a variant. Special attention is paid to the so-called azygos vein indentation. The most marked depression variants in our series are reproduced. When a depression is found in contiguity with a pathological mass and does not exceed the range of the variants, one cannot be sure that the mass is indeed the cause of this depression. In patients with bronchogenic carcinoma, depression of the wall of the trachea or mainstem bronchus seems to be no better sign for the metastatic nature of lymphadenopathy than size per se.

Azygos Vein↗