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Biomedical subjects

P Maeder

Publications and source records attributed to P Maeder.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Magnetic resonance angiography in vertebro-basilar ischemic accidents].

This study evaluates the use of MR angiography in the diagnosis of vertebrobasilar stroke. The MRI/MR angiography and clinical presentation of 50 unselected adult patients who presented with ischemic symptoms in the vertebrobasilar territory (10 TIAs, 40 strokes) were prospectively evaluated. Conventional T1 and T2-spin echo sequences were obtained for evaluation of the brain parenchyma, with gadolinium injection in 41 cases and 3D time-of-flight MR angiography in all patients. Data were reconstructed with a maximal intensity projection algorithm and displayed in 3D. Arterial and parenchymal lesions and clinical data were correlated. MR angiography showed intracranial vertebrobasilar lesions in 30 patients (5 stenosis or occlusion of a vertebral artery, 17 stenosis or occlusion of the basilar artery, 6 stenosis of arterial branches of the basilar artery, 10 dolichoectasia of the basilar artery). 7 patients had multiple lesions. Recognized etiologies of the strokes were: 23 vertebrobasilar lesions, 16 nonvertebrobasilar causes, 6 mixed (vertebrobasilar and associated alternative causes) cases, while 5 cases had no recognized cause of stroke. Our study demonstrates a high incidence of intracranial arterial lesions in patients suffering from vertebrobasilar stroke and suggests that MRA can help in a noninvasive way to determine the origin of vertebrobasilar strokes.

Adult↗
PubMed1996

Cushing's disease due to a giant pituitary adenoma in early infancy: CT and MRI features.

We report the case of a 12-month-old girl presenting with diabetes insipidus and Cushing s disease. Brain magnetic resonance imaging (MRI) demonstrated a large tumour arising from the sella turcica, extending up to the foramen of Monro and invading the cavernous sinuses. Surgery was performed to remove the suprasellar part of the tumour, and histology revealed an adrenocorticotrophin (ACTH) secreting pituitary adenoma. This entity is very rare in this age group and the MRI features have not previously been described.

Adenoma↗
PubMed1996

[Spontaneous intracranial hypotension syndrome].

Spontaneous intracranial hypotension is a rare but well known entity first described by the German neurosurgeon Schaltenbrand. We report the clinical and radiological findings of four patients (2 males, 2 females, mean age 55 years) presenting with this clinical entity and peculiar constant MRI findings. Intense postural headache was present in all patients together with a very low CSF pressure at lumbar tap although none of the patients had any history of recent lumbar puncture, spinal or cerebral surgery or cranio-cervical trauma. MRI revealed in all patients an intense meningeal enhancement and thickening which was most prominent on the dural side of the subdural space. The ventricular system was thin, presenting almost like slit ventricules. A downward shift of the cerebellar tonsils and hemorrhagic subdural collections were also observed in two patients. Biopsy of meninges performed in two patients showed fibrosis of the leptomeninges together with signs of old hemorrhage in one case. We postulate that histologic and radiologic changes are due to chronic subdural bleeding in relation with abnormal displacement of the nervous structures due to intracranial hypotension. The underlying cause of spontaneous intracranial hypotension is rarely established and the course of the disease is benign. Some authors have advocated to perform isotopic cysternography in search for a CSF leak, particularly in the spine, that could be surgically corrected. No such investigation has been conducted yet in our patients because the spontaneous evolution has been mostly favorable.

Cerebrovascular Disorders↗
PubMed1995

[Multiple familial pheochromocytomas: sonographic demonstration of multiple adrenal, celiac and bladder localizations in a child].

Familial pheochromocytoma is an uncommon form of this neoplasia. It is characterized by an autosomal dominant inheritance and multicentric locations. It is more frequently encountered in children, but with a smaller risk of malignant transformation than in adults. The familial form may be associated with other disorders, particularly with multiple endocrine neoplasia (MEN), Von Hippel-Lindau's disease and Von Recklinghausen's disease. We report the case of a nine-year-old boy with multiple familial pheochromocytoma in whom sonography allowed to demonstrate five localizations.

Adrenal Gland Neoplasms↗
PubMed1995

Xenon CT measurement of cerebral blood flow in hydrocephalus.

Since the recognition of normal-pressure hydrocephalus as an entity (1965), ventriculo-atrial or peritoneal shunting has been proposed as a treatment for this disease. Unfortunately, selection of patients who would benefit from shunting has always been difficult, and no clinical or brain imaging criteria have been entirely satisfactory. Functional studies intended to measure the local cerebral blood flow (lCBF) seem more promising. Xenon CT CBF measurement has been chosen because of its ability to measure deep white matter lCBF with good spatial resolution. This preliminary study reports the results of lCBF measurement in four patients examined by this technique before and after shunting or cerebrospinal fluid subtraction by lumbar puncture. In this small collective the two patients who improved clinically after shunting or lumbar puncture also had a substantial improvement in deep white matter lCBF.

Administration, Inhalation↗
PubMed1995

Vascular ataxic hemiparesis: a re-evaluation.

Ataxic hemiparesis is commonly considered as one of the "typical" lacunar syndromes. Using the prospective stroke registries from Lausanne and Besançon, 100 patients were selected consecutively (73% men, 27% women; age 64.7 (SD 13.6) years) with a first stroke and ataxic hemiparesis (hemiparesis or pyramidal signs and ipsilateral incoordination without sensory loss). Brain CT or MRI was performed on all patients. A primary haemorrhage was present in 5%, an infarct in 72%, isolated leukoaraiosis in 9%, and no apparent abnormality in 14%. The locations of lesions were the internal capsule (39%), pons (19%), thalamus (13%), corona radiata (13%), lentiform nucleus (8%), cerebellum (superior cerebellar artery territory) (4%), and frontal cortex (anterior cerebral artery territory) (4%). The clinical features of ataxic hemiparesis with different locations were almost identical. Only minor associated signs allowed the localisation of the lesions (paraesthesiae with a lesion in the thalamus; nystagmus or dysarthria with a cerebellar or pontine location). Crural paresis with homolateral ataxia was seen only with cortical paramedian frontal lesions. Presumed hypertensive small artery disease was not always found, but was still the leading cause of stroke, being present in 59% of the patients and in 62% of those with small deep infarcts. A potential source of embolism (arterial or cardiac) was found in one fourth of the patients. Therefore no definite association can be made between ataxic hemiparesis and lacunar infarction. In particular, so called uncommon lesion locations may not be rare. After extensive investigations a diagnosis of lacunar infarct can be retained in only slightly more than half of the cases.

Adult↗
PubMed1995

Magnetic resonance imaging of the shoulder in children with brachial pLexus birth palsy.

Five patients suffering from Erb-Duchenne brachial plexus birth palsy were prospectively studied with MRI. A group of 11 healthy children was used as a control to understand the MRI anatomy of the normal growing glenohumeral joint. A hypoplastic and flattened posterior part of the glenoid fossa and a blunt posterior labrum were found in all patients. Four patients had a blunt anterior labrum and a flattened humeral head. Three patients presented with a posterior subluxation of the humeral head. These results suggest that MRI provides a non-ionising and non-invasive method of demonstrating the early abnormalities of the shoulder associated with obstetrical brachial plexus paralysis, which may prompt orthopaedic correction.

Brachial Plexus↗
PubMed1994

The "jerky dystonic unsteady hand": a delayed motor syndrome in posterior thalamic infarctions.

We report the cases of three patients with a thalamic infarct in the territory of the posterior choroidal artery involving the posterior thalamic nuclei. These patients developed delayed complex hyperkinetic motor syndromes, associating ataxia, tremor, dystonia, myoclonus and chorea, which we call "the jerky dystonic unsteady hand". One patient had a severe myoclonic and ataxic-dystonic choreoathetosis; another showed a so-called rubral tremor (myoclonic ataxia with resting, action, and wing-beating tremor) with dystonia; and the third one had a dystonic and ataxic hand with intermittent mild action myoclonus. All of them had sensory dysfunction; two had also presented with a painful Dejérine-Roussy syndrome. All had CT or MRI-proven infarcts in the territory of the posterior cerebral artery involving the posterior choroidal territory with an abnormal signal in the posterior area of the thalamus (pulvinar nucleus) but sparing the other thalamic, subthalamic and midbrain structures. These delayed myoclonic complex hyperkinetic syndromes have not been reported before, and we did not observe them in other topographic forms of thalamic infarcts. They may thus represent a new entity of movement disorders due to lesions in the posterior thalamic nuclei, with specificity for posterior choroidal artery infarcts.

Adult↗
PubMed1994

Pure midbrain infarction: clinical syndromes, MRI, and etiologic patterns.

We studied 22 patients with first stroke and infarct limited to the midbrain on MRI. We selected these patients (8%) from 281 with posterior circulation infarct admitted consecutively into a primary care center. All patients underwent a systematic protocol of investigations including MR imaging and angiography, and echocardiography. Most infarcts fitted well to arterial territories drawn in preestablished templates. Middle midbrain involvement was the most common, mainly in the paramedian territory supplied by the basilar artery. Infarct in the mesencephalic territory of the posterior cerebral artery was less common, while superior cerebellar artery territory infarct was extremely rare, and posterior choroidal artery territory infarct did not occur. The neurologic picture was dominated by eye-movement disorders. Patients with isolated upper or lower midbrain infarct had no localizing clinical findings, but patients with middle midbrain infarct had a localizing picture mainly with nuclear or fascicular third nerve palsies that commonly developed in isolation. Vertical gaze paresis, pure motor hemiparesis, four-limb ataxia from unilateral lesion, and hypesthetic ataxic hemiparesis also occurred. Contrary to a common view, cardioembolism was not a more common etiology than basilar artery stenosis or small-vessel disease.

Aged↗
PubMed1993

[Role of radiology in the diagnosis of aortic dissection].

Aortic dissection requires a prompt diagnosis and must be treated without delay in order to reduce the mortality rate. Whereas aortic dissection involving the ascending aorta (type A) requires immediate surgery, aortic dissection involving the descending aorta (type B) will usually be treated conservatively. This review article reevaluates the respective efficiency of conventional and modern radiological means offered in a well equipped university hospital.

Aortic Dissection↗
PubMed1993

Magnetic resonance imaging with gadolinium contrast agent in small deep (lacunar) cerebral infarcts.

OBJECTIVE: To assess gadolinium-diethylenetriamine-pentaacetic acid (Gd-DTPA) contrast-enhanced magnetic resonance (MR) imaging as an index of recent symptomatic small deep cerebral infarcts (SDCIs). DESIGN: Prospective case series. SETTINGS: Primary-care center. PATIENTS: Thirty-one consecutive patients presenting with the clinical diagnosis of SDCI in the territory of the perforators of the internal carotid artery or the vertebrobasilar system and confirmed by MR imaging. INTERVENTION: Rapid intravenous infusion of Gd-DTPA 5 to 10 minutes prior to acquisition of T1-weighted images. MAIN OUTCOME MEASURES: Precise clinicotopographic correlation on MR scans. RESULTS: Non-contrast-enhanced MR imaging allowed precise clinicotopographic correlation in five (38%) of 13 patients with SDCI symptoms in the internal carotid artery territory. After Gd-DTPA administration, precise clinicotopographic correlation improved in 11 (85%) of 13 patients. In five patients, precise correlation was possible only after Gd-DTPA enhancement. Nonenhanced MR imaging allowed precise clinicotopographic correlation in 15 (83%) of 18 patients with SDCI symptoms in the vertebrobasilar territory. After Gd-DTPA administration, we could establish precise clinicotopographic correlation in all patients with SDCIs in the vertebrobasilar territory. In three patients, precise correlation was possible only after Gd-DTPA contrast enhancement. In seven (23%) of 31 patients, Gd-DTPA failed to enhance symptomatic lesion: in five patients MR scans were performed early (less than 7 days) and in two patients later in the course (greater than 7 days). CONCLUSIONS: Although Gd-DTPA administration is unlikely to improve the sensitivity of MR images in visualizing SDCIs, it significantly improves the rate of precise clinicoanatomic correlation. All enhancing lesions showed precise clinicotopographic correlation. Enhancement may be absent in the acute phase (less than 7 days).

Aged↗
PubMed1993

Spread of blood in cerebrospinal fluid following craniotomy simulates spinal metastases.

Postoperative myelography with water-soluble contrast media was performed in 36 children with a diagnosis of posterior cranial fossa tumour. The myelograms were normal in 15. In 5 an intramedullary tumour was present and 3 of these had in addition subarachnoid changes as evidence of tumour spread. The remaining 16 patient had subarachnoid changes of a different character, mainly located in the posterior thoracic region and similar to those seen after subarachnoid haemorrhage. It is suggested that they represent adhesions caused by blood from the operation. The blood is assumed to be distributed by the large cerebrospinal fluid pulsations to the cervical and thoracic regions. It is important to recognise and differentiate subarachnoid changes due to tumour and to postoperative adhesions to avoid unnecessary radiotherapy to the spinal cord.

Blood Loss, Surgical↗
PubMed1993

Acute fatal parainfectious cerebellar swelling in two children. A rare or an overlooked situation?

We report 2 previously healthy children who developed sudden unexpected respiratory arrest and brain death, during a presumed Epstein-Barr meningitis in one case and a multisystemic infection of unknown etiology in the other. Diffuse swelling of the cerebellum with upward transtentorial and downward tonsillar herniation, shown by brain CT-scan and MRI obtained after the acute event, was the most probable cause of death. Review of CT images performed before or at the onset of deterioration already showed discrete signs of early upward herniation of the cerebellar vermis that were initially overlooked. At autopsy in the first case, an acute lymphomonocytic meningoencephalitis with predominant involvement of the cerebellum was observed. Few similar cases were found in the literature, indicating that acute cerebellar swelling is either a very rare or an unrecognized, possibly preventable cause of death in acute inflammatory or non-inflammatory encephalopathies in children.

Autopsy↗
PubMed1993

The etiology of posterior circulation infarcts: a prospective study using magnetic resonance imaging and magnetic resonance angiography.

In a prospective study of 70 patients with infarcts in the posterior circulation admitted consecutively to a population-based primary-care center, we assessed infarct location and etiology using magnetic resonance imaging, three-dimensional time-of-flight magnetic resonance angiography, and noninvasive cardiac tests. The brainstem (mainly the paramedian pons) was the most commonly infarcted site (41/70, 59%), followed by the cerebellum (33/70, 47%). Combined supra- and infratentorial multiple vertebrobasilar infarcts occurred in 11 patients (16%). Overall, 27 patients (39%) had > or = 50% stenosis or occlusion of the basilar artery. There were other large-artery lesions in 19 patients (27%), including vertebral (V2-V4) stenosis or occlusion (in seven) and dolichoectatic vertebral/basilar arteries (in 12). Fifteen of the 70 patients had a potential cardiac source of embolism, which coexisted with large-artery disease in more than one-third of the cases. Cerebellar infarct without concomitant brainstem or occipital infarct was associated with cardioembolism (67%), while isolated paramedian pontine or midbrain infarct was associated with basilar artery stenosis (71%), suggesting in situ occlusion of the mouth of the perforators off the stenosed basilar artery. After exclusion of other potential causes of stroke, presumed small-artery disease associated with chronic hypertension remained the likely etiology in only 11 patients (16%), but these infarcts were not associated with any of the classical lacunar syndromes. Our findings emphasize the high frequency of severe intracranial large-artery disease in posterior circulation infarcts.

Aged↗