Correlation of regional cerebral blood flow measured by stable xenon CT and perfusion MRI.

Purpose: The purpose of this work was to investigate the validity of perfusion MRI in comparison with stable xenon CT for evaluating regional cerebral blood flow (rCBF).

Method: The rCBF was measured by xenon CT and perfusion MRI within a 24 h interval in 10 patients (mean +/- SD age 63 +/- 10 years). For perfusion MRI, absolute values of rCBF were calculated based on the indicator dilution theory after injection of 0.

Changes of cerebral perfusion after osmotherapy in acute cerebral edema assessed with perfusion weighted MRI.

Perfusion is thought to be impaired in brain edema due to reduced perfusion pressure. Brain edema therapy is assumed to improve perfusion. We assessed regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV) and mean transit time of blood (MTT) using perfusion-weighted magnetic resonance imaging (MRI) in 15 patients showing acute local brain edema due to infarction or intracerebral hematoma.

Influence of the angiographic internal carotid artery stenosis assessment method on indicating carotid surgery.

Background: To estimate the influence of different kinds of angiographic internal carotid artery (ICA) stenosis assessment methods on clinical decision making on carotid surgery.

Method: One hundred angiographically proven ICA lesions in 65 patients (54 men, 11 women, mean age +/- SD, 64 +/- 8 years) were evaluated by simultaneous biplane angiography. The angiograms were analyzed using three kinds of linear diameter reduction methods [North American (NASCET), and European (ECST) carotid surgery trial method, common carotid artery method (CC)], and five area reduction methods reflecting more accurately the anatomical degree of stenosis [squared NASCET, ECST and CC (N2, E2, CC2), combined stenosis estimation of two projections (NASCET-bi, ECST-bi)].

Patient doses from standard and spiral CT of the head using a fast twin-beam system.

Investigations were carried out on a novel type of CT scanner, the Elscint CT-Twin, for comparison and optimization of the patient dose caused by standard and spiral CT of the head. For selected CT parameters, organ doses of the Alderson head phantom were measured with thermoluminescent dosemeters. Organ doses were also calculated using the normalized computed tomography dose index (CTDIn) combined with organ dose conversion factors.

[Perfusion-MRI in cerebral infarct].

Purpose: To investigate the hemodynamic changes in patients with acute cerebral stroke by perfusion MRI.

Material And Methods: In 12 patients with acute stroke in the territory of the middle cerebral artery, perfusion MRI was performed. Peak time, mean transit time, regional cerebral blood volume and regional cerebral blood flow were calculated in the infarction, the peri-infarction area and the contralateral hemisphere.

[Diffusion-weighted magnetic resonance imaging in the diagnosis of cerebral infarct].

Forty-one patients demonstrating clinical symptoms for cerebral infarction were investigated by magnetic resonance imaging with diffusion-weighted echo-planar imaging (DWI) and T2-weighted imaging (T2WI). In 8 patients only DWI showed the cerebral lesions clearly. One patient with positive DWI and T2WI suffered from HSV encephalitis.

Stereotactic neurosurgery planning with 3-D spiral CT-angiography.

Objective: To assess the feasibility and value of spiral CT angiography of the brain vessels for the planning of neurosurgical stereotactic interventions.

Material And Methods: Fourty-two patients harboring cerebral lesions underwent spiral CT angiography prior to stereotactic biopsy. Thin spiral CT slices with a collimator slice thickness of 1 mm and a pitch of 1 were used.

[CT-angiography in planning stereotaxic biopsies].

Twenty-one patients referred for stereotactic biopsy were studied by CT angiography. Helical CT with 1 mm collimation was obtained (pitch of 1:1). Multiplanar reconstructions were performed; maximum intensity projections and shaded-surface displays were generated by connectivity-based editing tools.

[Value of CT-angiography in diagnosis of cerebral sinus and venous thromboses].

Dural sinus thrombosis is not uncommon. Due to the nonspecific symptomatology, as well as the manifold etiology, clinical diagnosis may be difficult. In these cases imaging procedures are frequently crucial in deciding how to proceed and how to treat.

[Angiographic quantification of stenoses of the internal carotid artery].

Background And Purpose: The method of measuring cartid stenosis is under discussion since different methods of quantifying carotid stenosis were used in the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Stenosis Trial (ECST).

Methods: Angiograms from 80 patients (105 cases of stenosis of the internal carotid artery), performed in a simultaneous biplanar manner, were retrospectively analyzed using the NASCET, the ECST method and a method based on measurement of the common carotid (CC) artery lumen diameter. Each linear measurement was converted into the ¿squared¿ method (NASCET2, ECST2, CC2).