Biomedical subjects

A Uske

Publications and source records attributed to A Uske.

41 records · Page 3Linked to original sources

PubMed1985

Intracranial vascular malformations: MR and CT imaging.

Twenty-four patients with 29 cerebrovascular malformations were evaluated with a combination of computed tomography (CT), angiography, and magnetic resonance (MR) imaging. Characteristics of the malformations on MR images were reviewed retrospectively, and a comparative evaluation of MR and CT images was made. Of 14 angiographically evident malformations, 13 intra-axial lesions were detected on both CT and MR images, and one dural malformation gave false-negative results on both modalities. The appearance of parenchymal lesions on MR images closely mirrored characteristic CT findings. Calcific foci were difficult to separate from vessels on both images. Clot was more easily identified on MR images. In the detection of 15 angiographically occult malformations, CT proved more sensitive when focal calcification was the only evidence of their presence. MR study failed to detect two small supratentorial lesions evidenced by faint calcifications on CT scans. In two patients, MR images showed small hemorrhages not detectable by CT, and MR provided strong evidence for the diagnosis of hematoma for 12 lesions. Angiographically evident malformations have a highly characteristic appearance on MR images. MR may be more sensitive than CT in the detection of small hemorrhagic foci associated with cryptic arteriovenous malformations and may add specificity in the diagnosis of occult malformations in some cases, but MR is less sensitive than CT for the detection of small calcified malformations.

Adolescent↗

PubMed1985

MR technology: effect of even-echo rephasing on calculated T2 values and T2 images.

In multiple spin-echo image sequences of blood flow, the "even-echo" phenomenon produces an absolute increase in signal magnitude from first- to second-echo images of normal vessels harboring slow flow. Distinguishing this from the apparent relatively high signal intensity seen on second-echo images in pathologic foci of stationary tissue is important to the diagnostician. Selected case material containing two tissue types was reviewed retrospectively: tissues known to harbor slow flow, such as normal veins and venous sinuses and vascular malformations, and tissues that have long transverse (T2) relaxation times and appear as intense structures on second-echo images, such as neoplasms, infarcts, and regions of demyelination. Calculations of T2 parameters were made by computer for defined regions of interest. T2 images were also generated. Visual inspection of the acquired images did not reliably distinguish increased intensity due to even-echo rephasing from the relative changes between adjacent tissues seen on second-echo images. More definitive differentiation of the even-echo phenomenon was provided by calculated values of T2 and computer-synthesized T2 images representing acquired intensity data of two-echo sequences. The synthesized images were especially useful when stationary tissue with lengthened T2 values was adjacent to or in proximity to vessels or vascular lesions. A five spin-echo image sequence was valuable for separating slow flow from stationary tissue by a technique of synthesizing T2-difference images using three consecutive echoes.

Brain Diseases↗

PubMed1984

Carotid artery occlusion. Delayed embolic ischemia from vertebrobasilar atheromatosis.

We described a patient with occlusion of an internal carotid artery in whom delayed transient ischemic attacks distal to the occlusion alternated with vertebrobasilar attacks. Microembolization through the vertebrobasilar system was emphasized because the middle cerebral artery was filled by the basilar artery through the posterior communicating artery, and one vertebral artery showed important atheromatous emboligenic changes. Other mechanisms appeared improbable because of the type of collateral circulation and absence of other associated emboligenic changes and hemodynamic phenomena.

Basilar Artery↗

PubMed1983

[Delayed epidural hematoma. Apropos of a series of 8 cases].

The authors report 8 patients who developed an epidural hematoma after having been submitted to 1 or 2 computed tomographies (CT) which did not yet show the hematoma. The initial CT was done 1 to 6 hours after the accident. The delayed hematoma was diagnosed 3 and a half hours to 7 days after the accident. Secondary clinical deterioration occurred in 6 patients and was dramatic in 4 of them. Delayed epidural hematoma seems to be a frequent event; our 8 cases represent 10 % of all epidural hematomas operated during the period under consideration. This has to be taken into account when taking care of head injured patients after negative CT. The authors propose a list of indications for repeating CT. The current views on mechanisms of formation of epidural hematomas are discussed in the light of the increasing number of reported cases of delayed epidural hematoma.

Adolescent↗

PubMedDate not supplied

Leukoencephalopathy in patients with ischemic stroke.

Thirty-one (16 women, 15 men; mean age 68 years) of 1,000 consecutive patients with an ischemic stroke investigated systematically with computed tomography (CT), Doppler, electrocardiography (ECG), and biological tests had a diffuse hypodensity of the cerebral hemispheric white matter on CT, a sign indicative of leukoencephalopathy. In 25 of the 31 patients, the acute infarct was deep. Leukoencephalopathy was more frequent in patients with a deep infarct (8%) than in patients in whom the cortex was involved (0.8%) (p less than 0.01). A history of progressive intellectual impairment (23%) and the finding of a mild or moderate impairment, or severe dementia (84%) were more frequent in study patients (p less than 0.05) than in 31 sex- and age-matched controls with an acute infarct of same size and topography but without leukoencephalopathy. A history of hypertension (81%) and high blood pressure on admission (166 +/- 19/96 +/- 12 mm Hg) were the most common risk factors and were more frequent in study patients (p less than 0.05) than in controls. On the other hand, study patients had a greater than or equal to 50% stenosis or occlusion of the carotid artery (13%) less often than controls (35%) (p less than 0.05). Diabetes (23%), elevated blood cholesterol (13%), hematocrit greater than 45% (23%), smoking (32%), and myocardial ischemia by history or ECG (45%) did not differ. These findings suggest that hypertension may be more strongly associated with leukoencephalopathy than with deep infarcts. In acute stroke patients, leukoencephalopathy on CT should not be considered a fortuitous finding.

Aged↗