Agenesis of the corpus callosum.
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Agenesis of Corpus Callosum↗
Biomedical subjects
L Remonda
Publications and source records attributed to L Remonda.
The site of atheromatosis in the subclavian and vertebral arteries and its implication for angioplasty.
We analysed the site of plaques and stenoses in the subclavian and vertebral arteries, to improve the safety of percutaneous transluminal angioplasty (PTA) in high-risk patients. These lesions were assessed on arteriograms of 35 patients with stenoses and occlusions of the subclavian and vertebral arteries; the degree of stenoses was measured. Of 19 subclavian artery stenoses 17 (89%) were in the segment proximal to the vertebral artery; 30 (79%) of 38 vertebral artery stenoses were on the medial wall. With this knowledge, a double-balloon technique using a simultaneous transbrachial and transfemoral approach for angioplasty of high-risk subclavian or combined subclavian and vertebral artery stenoses and occlusions was used successfully in seven patients. This new technique may broaden the endovascular therapeutic possibilities in the rare but dangerous situation where plaque extends directly from the stenotic subclavian artery into the origin of the vertebral artery.
Aged↗
Clinical single-shot diffusion-weighted MRI of the human brain on a short-bore medium-field imager.
Diffusion-weighted MRI (DWI) is becoming important for assessment of acute stroke. Until recently single-shot DWI required expensive technology such as echoplanar imaging (EPI) available only at some research sites. A new medium-field (1.0 T) short-bore MR imager has been developed with which DWI data sets can be acquired. We prospectively studied 169 patients on this 1.0 T commercial system. After conventional imaging, DWI was performed with a single-shot multi-slice sequence with b values 0 an 900 s/mm2, and with the gradients switched in three directions. The apparent diffusion coefficients were calculated with online calculation software. There were 50 patients with totally normal MRI, and 17 had strokes, these strokes were detected as areas of high signal on the images at a maximal b value. There was a drop in the ADC in ischaemic regions: in sub-acute infarcts, the values were between 0.41 and 0.531 x 10(-3) mm2/s. In old infarcts the ADC was 1.15 x 10(-3) mm2/s. Cerebrospinal fluid (CSF) gave low signal whereas areas in the brain had more intermediate intensities (CSF: 3.00; deep white matter: 0.75, cortical grey matter: 0.80, basal ganglia (thalamus): 0.70 and cerebellar white matter: 0.65 x 10(-3) mm2/s. Anisotropy was detected as areas of restricted diffusion along the tracts. These preliminary data show that DWI can be acquired successfully on a medium-field short-bore system. This should allow the technique to be implemented at more sites, therefore facilitating the diagnosis of acute stroke and rendering early intervention feasible.
Brain↗
Interventional neuroradiology. Recent developments and anaesthesiologic aspects.
AIM: To summarise recent developments in interventional neuroradiology (INR) and to discuss related anaesthesiologic considerations. SUMMARY: Important Procedures: embolisation of cerebral aneurysms with Guglielmi detachable coils (GDC) as well as intra-arterial thrombolysis and angioplasty for acute ischaemic stroke and chronic atherosclerotic stenosis of cerebral arteries have been recently introduced into clinical practice. Their role in the management of aneurysms and cerebral ischaemia still remains to be defined. Embolisation of strongly vascularised neoplasms, arteriovenous malformations or fistulas and percutaneous transluminal angioplasty of refractory vasospasms after subarachnoid haemorrhage are standard procedures with established indications. The balloon occlusion test of the carotid artery and the WADA test are also frequently performed interventions in INR. ANAESTHETIC CONSIDERATIONS: The role of the anaesthetist in INR consists in providing patient comfort by analgesia and sedation, adequate monitoring, maintenance of vital functions and (if required) the management of systemic heparinisation. The patient's underlying condition, the duration and the kind of intervention have to be considered to decide on the anaesthetic management. Most of the procedures can safely be performed under light sedation, which allows continuous neurological evaluation of the patient. Knowledge of the risks and hazards of the different procedures and close collaboration with the neuroradiologist form the basis for appropriate management in case of a potentially fatal ischaemic or haemorrhagic complication that may occur in 1 to 8% of interventions. For prompt control of airway, respiration and blood pressure in these emergencies experienced anaesthesia staff is required.
Anesthesia↗
Rotatory seizures in a patient with tuberous sclerosis.
We present an 11-year-old girl with tuberous sclerosis who developed seizures characterized by circling behavior. Rotatory seizures are uncommon and occur mainly secondary to a focal pathology. Our patient had a right temporal epileptic focus, confirmed by magnetic resonance imaging (MRI) to be a subcortical lesion in the right temporal region. This case is probably the first reported case of tuberous sclerosis associated with rotatory seizures with an ictal EEG.
Brain Mapping↗
[Diffusion-weighted imaging in acute stroke].
Magnetic resonance imaging represents today the most important tool in neuroradiology for both clinical practice and research. MRI allows imaging of the human body in 2 or 3 dimensions with variable tissue contrast. The natural diffusion of tissue protons can now be used as a supplementary contrast mechanism. Different MRI techniques can be used to obtain clinically useful diffusion-weighted images. These techniques all require the use of strong gradient pulses in order to obtain the diffusion contrast. In the current article, the most important physical principles of diffusion measurement are presented. After a short introduction into the basic physical principles, we will present the prerequisites and limitations of clinically relevant applications today. Finally a few select examples of clinical use of these techniques in the acute diagnosis of stroke will be presented.
Acute Disease↗
Pure methotrexate encephalopathy presenting with seizures: CT and MRI features.
With the advent of chemotherapy, mortality rates in acute lymphoblastic leukaemia (ALL) have decreased, but complications in the central nervous system have appeared. These include direct involvement of the brain itself and the development of chemotherapy-related encephalopathy as a delayed reaction. In most reported cases, this encephalopathy is believed to be due to necrotising angiitis arising from the combination of chemotherapy with adjuvant radiotherapy. We report the cases of four children with ALL who had been treated with high-dose intravenous and intrathecal chemotherapy but no radiation therapy, and who were admitted to hospital because of seizures. CT of the brain revealed the presence of diffuse periventricular white matter hypodensities in all cases and subcortical hyperdense foci in three cases. MRI showed diffuse hyperintense white matter lesions on T2-weighted images in all four patients; hypointense changes were observed on susceptibility-sensitive FLASH sequences in the hyperdense foci seen on CT as well as changes that were hyperintense on T1-weighted images. It was, therefore, concluded that the lesions corresponded to a leukoencephalopathy with calcific deposits. These findings are of a pure form of methotrexate encephalopathy causing seizures.
Antineoplastic Agents↗
Subependymal thalamic haemorrhage due to a thalamoperforating artery aneurysm.
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Cerebral Angiography↗
Carotid artery stenosis, occlusion, and pseudo-occlusion: first-pass, gadolinium-enhanced, three-dimensional MR angiography--preliminary study.
PURPOSE: To determine the accuracy of gadolinium-enhanced three-dimensional magnetic resonance (MR) angiography in the evaluation of carotid artery stenosis. MATERIALS AND METHODS: A prospective blinded comparison of first-pass MR angiography with conventional digital subtraction angiography (DSA) was performed in 21 patients suspected of having carotid artery stenosis. MR angiography was performed on a 1.5-T magnet with gradient overdrive equipment, with a coronal radio-frequency-spoiled, three-dimensional, fast low-angle shot sequence after intravenous injection of contrast material. The guidelines of the North America Symptomatic Carotid Endarterectomy Trial for measuring stenosis of the internal carotid artery were applied on maximum intensity projection images and conventional angiograms. RESULTS: Grading of stenoses at MR angiography agreed with that at DSA in 92% of the 44 carotid arteries. In the 18 carotid arteries with severe stenosis (70%-99%), agreement was 94%. All internal carotid occlusions (n = 7) or pseudo-occlusions (n = 3) were accurately detected with MR angiography. CONCLUSION: The accuracy of gadolinium-enhanced MR angiography in characterizing the degree of carotid stenosis was high. Findings with MR angiography were accurate for differentiating between occlusion and pseudo-occlusion.
Aged↗
Selective intra-arterial fibrinolysis of acute central retinal artery occlusion.
BACKGROUND AND PURPOSE: Occlusion of the central retinal artery (CRAO) causes a sudden decrease of monocular vision. Because early restoration of blood flow may improve outcome, we attempted to treat CRAO with selective intra-arterial fibrinolysis. METHODS: Intra-arterial fibrinolysis was performed within 6 hours after symptom onset in 17 patients with thromboembolic CRAO. Symptoms were painless, acute and severe decrease of vision. Urokinase (100 000 to 900 000 IU) was given through a microcatheter into the ophthalmic artery over 10 to 90 minutes. For comparison, the history and visual outcome of 15 control patients who did not receive fibrinolytics were evaluated. In both groups some of the patients underwent paracentesis and/or received carboanhydrase inhibitors. RESULTS: Patients who underwent fibrinolysis fared better than control patients (P=0.01). Three patients (17.6%) recovered completely after fibrinolysis and regained visual acuity of 20/20 (n=2) to 25/20 (n=1). Two additional patients (11.8%) showed a marked improvement to a visual acuity of 20/30. In 6 patients (35. 3%) vision improved slightly. They were able to count fingers, detect hand movements, or perceive light. In 6 patients (35.3%), fibrinolytic treatment was without effect. Among control patients, 1 patient (6.7%) showed partial, 4 patients (26.7%) minimal, and 10 (66.7%) no improvement of vision. CONCLUSIONS: A complete or marked improvement of visual acuity was achieved in one third of intra-arterial fibrinolysis patients but in none of the control patients. Intra-arterial fibrinolysis seems to have the potential to "lighten" the spontaneously poor outcome of CRAO.
Acute Disease↗
Local intra-arterial thrombolysis in acute ischemic stroke.
BACKGROUND AND PURPOSE: We performed a retrospective analysis of the prognostic factors in patients treated with local intra-arterial thrombolysis (LIT). The purpose of this study was to evaluate the safety and efficacy of LIT using urokinase in patients with acute ischemic stroke of the anterior or posterior circulation and to determine the influence of clinical and radiological parameters on outcome. METHODS: Forty-three patients were treated with LIT using urokinase (median dose, 0.75x10(6) IU). The median National Institutes of Health Stroke Scale (NIHSS) score at hospital admission was 18 (range, 9 to 36). Nine patients had occlusions of the internal carotid artery (ICA), 23 of the middle cerebral artery (MCA), 1 of the anterior cerebral artery, and 10 of the basilar artery (BA). Outcome was assessed after 3 months and classified as good for Rankin Scale (RS) scores of 0 to 3 and poor for RS scores of 4 or 5 and death. RESULTS: Nine patients (21%) recovered to RS scores 0 or 1, 17 (40%) to scores of 2 or 3, and 7 (16%) to scores of 4 or 5. Ten patients (23%) died. Outcome was good in 17 patients (80%) with MCA occlusions, in 3 patients (33%) with ICA, and in 5 patients (50%) with BA occlusions. Good outcome was associated with an initial NIHSS score of <20 (P<0.001), improvement by 4 or more points on NIHSS score within 24 hours (P=0.001), and vessel recanalization (P=0.02). Recanalization was more likely if LIT was started within 4 hours (P=0.01). Symptomatic cerebral hemorrhage occurred in 2 patients (4.7%). CONCLUSIONS: LIT was most efficacious in patients with MCA and BA occlusions when the initial NIHSS score was less than 20 and when treated within 4 hours. It is of limited value in patients with distal ICA occlusions.
Acute Disease↗
MR angiography with ultrashort echo time in cerebral aneurysms treated with Guglielmi detachable coils.
We evaluated a time-of-flight three-dimensional MR angiographic sequence with an ultrashort echo time for its ability to characterize the perfusional state of cerebral aneurysms that had been treated with Guglielmi detachable coils and to depict adjacent cerebral arteries. The results were compared with findings at conventional MR angiography and digital subtraction angiography. Adjacent vessels were seen better in 36% of patients imaged with the new technique. Both MR angiographic methods detected residual cerebral aneurysmal perfusion with a tendency to overestimate the patent portion of the aneurysm.
Adult↗
High-resolution echo-planar imaging of the brain: is it suitable for routine clinical imaging?
To assess the value of echo-planar imaging (EPI) for ultra-fast routine clinical diagnostic MRI, we compared four different EPI sequences with conventional T2-weighted spin-echo images on a commercial clinical imager. We examined 25 randomly selected patients who posed different clinical questions. The images were interpreted by two experienced neuroradiologists blinded as to the sequence used. Image quality and diagnostic certainty were evaluated and the main diagnosis established from the EPI study was compared to that obtained from the T2-weighted images. Finally, EPI- and T2-based diagnoses were compared with the diagnosis resulting from a complete MRI examination. Apart from one sequence that was generally rated low as regards both diagnostic certainty and image quality, the EPI sequences were comparable to each other, but inferior to the T2-weighted images. However, two EPI sequences gave better diagnostic results than T2-weighted images compared to the full MRI examination. Gradient-echo EPI was particularly sensitive to haemorrhagic lesions. All normal cases were correctly identified on EPI studies. Only two pathological cases were missed; both had isolated cranial nerve lesions. The absence of false-positive results and the high sensitivity to ischaemic and mass lesions mean that EPI can be used for ultra-fast screening. However, from these initial studies, EPI seems unsuitable for neuroradiological investigation of patients who may have subtle lesions whose detection requires either special sequences or administration of contrast medium. EPI can nevertheless be used in addition to high-resolution T1-weighted images and may replace T2-weighted spin-echo sequences for special indications.
Adolescent↗
Retardation of myelination due to dietary vitamin B12 deficiency: cranial MRI findings.
Vitamin B12 deficiency is known to be associated with signs of demyelination, usually in the spinal cord. Lack of vitamin B12 in the maternal diet during pregnancy has been shown to cause severe retardation of myelination in the nervous system. We report the case of a 14(1)/2-month-old child of strictly vegetarian parents who presented with severe psychomotor retardation. This severely hypotonic child had anemia due to insufficient maternal intake of vitamin B12 with associated megaloblastic anemia. MRI of the brain revealed severe brain atrophy with signs of retarded myelination, the frontal and temporal lobes being most severely affected. It was concluded that this myelination retardation was due to insufficient intake of vitamin B12 and vitamin B12 therapy was instituted. The patient responded well with improvement of clinical and imaging abnormalities. We stress the importance of MRI in the diagnosis and follow-up of patients with suspected diseases of myelination.
Anemia, Megaloblastic↗
Perinatal ultrasonography and magnetic resonance imaging findings in congenital hydrocephalus associated with fetal intraventricular hemorrhage.
OBJECTIVE: We present the case histories of three premature infants with congenital posthemorrhagic hydrocephalus. STUDY DESIGN: The timing of the lesion was monitored in utero in two of the three cases. Magnetic resonance imaging studies (prenatal in one case, within 24 hours of birth in all three cases) established the duration of the lesions and thereby added to the ultrasonographic findings. RESULTS: All three patients demonstrated a similar pattern of lesions, consisting of (1) unilateral germinal matrix hemorrhage with cystic resorption, (2) residual blood in the cerebrospinal fluid with a "granular" ependymal reaction, (3) asymmetric ventriculomegaly predominating on the side of the hemorrhage with mild atrophy and periventricular cysts, and (4) partial hypoplasia of the ipsilateral thalamus. On the basis of two cases in which information about the pregnancy was available and in which fetal oligohydramnios without ruptured membranes was detected, we assume that this pattern of lesions may have resulted from a hypoxic-ischemic episode followed by intraventricular hemorrhage. CONCLUSIONS: Because these three infants with congenital hydrocephalus were born during a period of only 18 months in a perinatal center serving a region with 16,000 live births per year, we speculate that a posthemorrhagic cause for congenital hydrocephalus underestimated.
Adult↗
[Special technics for angioplasty of the brachiocephalic vessels].
PURPOSE: Description of special techniques for retrograde angioplasty of cerebral arteries with protection of the brain. MATERIAL AND METHOD: During the last 3 years, 51 dilatations of cerebral vessels were carried out in 45 patients; in 8, special techniques were required. In cases with particular operative risks, angioplasty of cerebral vessels can be performed using various techniques (double catheter [8 cases], retrograde PTA [8 cases], kissing balloon technique [3 cases]). RESULTS: All stenoses were successfully dilated, using a local anaesthetic. One patient with a double stenosis of the common carotid artery developed severe headache and visual disturbances in the ipsilateral eye following dilatation of a tight stenosis with total remission of all symptoms within 24 hours. CONCLUSION: Stenoses of cerebral arteries where surgery would be difficult and associated with a high risk can be dilated by retrograde PTA using a double catheter technique with a low complication rate.
Aged↗
[Unilateral moyamoya syndrome: transcranial color duplex ultrasonography, magnetic resonance imaging (MRI) and angiography].
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Angiography, Digital Subtraction↗
Nontraumatic spinal epidural hematomas. MR features.
PURPOSE: Spinal epidural hematoma (SEH) is a rare clinical entity with a bleak outcome. The aim of our study was to establish the value of MR findings in the diagnosis of nontraumatic SEH. MATERIAL AND METHODS: Seven patients with nontraumatic SEH were examined by MR at 1.5 T. Two patients were under anticoagulation therapy with heparin, and 2 others were taking salicylic acid. One patient had lupus erythematodes with a marked thrombocytopenia. One patient had a spinal arteriovenous malformation. RESULTS: MR imaging permitted the accurate localization of extradural intraspinal expansive lesions which exhibited the characteristic signal intensities of blood. Five patients underwent laminectomy and evacuation of the hematoma. In the acute phase, the hematomas appeared isointense when compared with the spinal cord on T1-weighted images and hyperintense on T2-weighted images. Later the hematomas were hyperintense on T1-weighted images and showed signals identical to those of cerebrospinal fluid (CSF) on T2-weighted images. CONCLUSION: MR imaging established the exact diagnosis and localization of SEH in all cases. MR also can provide useful information about the age of the hematomas.
Acute Disease↗