[Cerebral vasculitis, a diagnostic labyrinth]. / Cerebrale vasculitis, een diagnostisch doolhof.

- A diagnosis of cerebral vasculitis is frequently considered in patients with new or progressive neurological symptoms for which there is no other explanation.- A clinician considering a diagnosis of cerebral vasculitis should be well aware of alternative diagnoses, since these are generally more common.- Several consecutive examinations are required for diagnosing cerebral vasculitis, because there is no diagnostic procedure that is highly sensitive as well as highly specific.- The added value of the different procedures may depend on the type of blood vessels involved.- Standard MRI examinations are sensitive but not specific.- Special MRI techniques now make it also possible to make images of the vessel wall itself.- Catheter angiography remains important, especially when non-invasive angiographic techniques do not reveal any abnormalities.- Brain biopsy can provide proof of cerebral vasculitis and also serves to exclude mimicking conditions.

Incompleteness of the circle of Willis is related to EEG-based shunting during carotid endarterectomy.

OBJECTIVES: The occurrence of cerebral ischemia during carotid endarterectomy (CEA) can be prevented by (selective) placement of an intraluminal shunt during cross-clamping. We set out to develop a rule to predict the likelihood for shunting during CEA based on preoperative assessment of collateral cerebral circulation and patient characteristics. METHODS: Patients who underwent CEA between 2004 and 2010 were included. Patients without preoperative magnetic resonance (MRA) or computed tomography angiography (CTA) were excluded. The primary endpoint was intraluminal shunt placement based on electroencephalography changes. Age, sex, cardiovascular risk factors peripheral artery disease, symptomatic status, degree of ipsilateral and contralateral carotid, status of the vertebral arteries, and morphology of the CoW were studied as potential predictors for shunt use. A prediction model was derived from a multivariable regression model using discrimination, calibration, and bootstrapping approaches and transformed into a clinical prediction model. RESULTS: A total of 431 patients were included, of which 65 patients (15%) received an intraluminal shunt. In the MRA group (n = 285) factors related to shunt use in multivariate analysis were ipsilateral carotid stenosis 90-99% (odds ratio [OR] 0.15, 95% CI 0.04-0.53), contralateral carotid occlusion (OR 4.29, 95% CI 1.68-10.95) and any not-visible anterior (OR 4.96, 95% CI 1.95-12.58) or ipsilateral posterior segment of the CoW (OR 5.08, 95% CI 2.10-12.32). In the CT group none of the factors were independently related to shunt use; therefore, only predictors describing morphology of CoW derived from MRA findings were included in our model. The c-statistic of this model was 0.79 (95% CI 0.72-0.86). Among patients with an estimated chance of needing a shunt of under 10% (49% of the population), the likelihood of shunting was 5%. In those in whom this chance was estimated higher than 30% (13% of the population) the likelihood was 51%. CONCLUSIONS: Among patients scheduled for CEA, assessment of cerebral arteries and of the configuration of the CoW based on MRA-derived images can help to identify patients with low and high likelihood of the need of shunt use during surgery.

Mixed perfusion: a combined blood supply to the brain tissue by multiple arteries.

From intra-arterial angiography studies and recently developed imaging techniques capable of non-invasively visualizing the flow territories of the cerebral arteries at brain tissue level, it is known that brain regions can be fed by multiple arteries simultaneously. This indicates a mixing of blood from separate supplying arteries before reaching the brain tissue. Herein, we aim to explore the various manners blood from different arteries may mix in both healthy individuals and in patients with steno-occlusive disease. Furthermore, the impact of cerebrovascular interventions on the blood flow patterns and its effect on the mixing of the blood supply is discussed. More accurate knowledge and understanding of the vascular sources of tissue perfusion, and potential mixing, may result in more efficient vascular therapies and interventions targeted specifically to affected brain tissue areas.

Arterial spin-labeling MR imaging measurements of timing parameters in patients with a carotid artery occlusion.

BACKGROUND AND PURPOSE: Arterial spin-labeling (ASL) with image acquisition at multiple delay times can be exploited in perfusion MR imaging to visualize and quantify the temporal dynamics of arterial blood inflow. In this study, we investigated the consequences of an internal carotid artery (ICA) occlusion and collateral blood flow on regional timing parameters. MATERIALS AND METHODS: Seventeen functionally independent patients with a symptomatic ICA occlusion (15 men, 2 women; mean age, 57 years) and 29 sex- and age-matched control subjects were investigated. ASL at multiple delay times was used to quantify regional cerebral blood flow (CBF) and the transit and trailing edge times (arterial timing parameters) reflecting, respectively, the beginning and end of the labeled bolus. Intra-arterial digital subtraction angiography and MR angiography were used to grade collaterals. RESULTS: In the hemisphere ipsilateral to the ICA occlusion, the CBF was lower in the anterior frontal (31 +/- 4 versus 47 +/- 3 mL/min/100 g, P < .01), posterior frontal (39 +/- 4 versus 55 +/- 2 mL/min/100 g, P < .01), and frontal parietal region (49 +/- 3 versus 61 +/- 3 mL/min/100 g, P = .04) than that in control subjects. The trailing edge of the frontal-parietal region was longer in the hemisphere ipsilateral to the ICA occlusion compared with that in control subjects (2225 +/- 167 versus 1593 +/- 35 ms, P < .01). In patients with leptomeningeal collateral flow, the trailing edge was longer in the anterior frontal region (2436 +/- 275 versus 1648 +/- 201 ms, P = .03) and shorter in the occipital region (1815 +/- 128 versus 2388 +/- 203 ms, P = .04), compared with patients without leptomeningeal collaterals. CONCLUSION: Regional assessment of timing parameters with ASL may provide valuable information on the cerebral hemodynamic status. In patients with leptomeningeal collaterals, the most impaired territory was found in the frontal lobe.

Level set based cerebral vasculature segmentation and diameter quantification in CT angiography.

A level set based method is presented for cerebral vascular tree segmentation from computed tomography angiography (CTA) data. The method starts with bone masking by registering a contrast enhanced scan with a low-dose mask scan in which the bone has been segmented. Then an estimate of the background and vessel intensity distributions is made based on the intensity histogram which is used to steer the level set to capture the vessel boundaries. The relevant parameters of the level set evolution are optimized using a training set. The method is validated by a diameter quantification study which is carried out on phantom data, representing ground truth, and 10 patient data sets. The results are compared to manually obtained measurements by two expert observers. In the phantom study, the method achieves similar accuracy as the observers, but is unbiased whereas the observers are biased, i.e., the results are 0.00+/-0.23 vs. -0.32+/-0.23 mm. Also, the method's reproducibility is slightly better than the inter-and intra-observer variability. In the patient study, the method is in agreement with the observers and also, the method's reproducibility -0.04+/-0.17 mm is similar to the inter-observer variability 0.06+/-0.17 mm. Since the method achieves comparable accuracy and reproducibility as the observers, and since the method achieves better performance than the observers with respect to ground truth, we conclude that the level set based vessel segmentation is a promising method for automated and accurate CTA diameter quantification.

A prospective study of fever in the accident and emergency department.

Body temperature is one of the most commonly performed measurements in the accident and emergency department, and is often used as the basis for clinical decisions. Fever is frequently assumed to indicate infection, but there are few data on unselected patients presenting acutely. We studied 101 consecutive patients with fever (temperature (38 degrees C) among 3991 presentations to two emergency departments in tertiary-care inner city hospitals. The commonest categorical discharge diagnosis, or diagnosis at seven days, was infection (63%). There were no simple clinical tests that could distinguish fever due to infection from other diagnoses. The results suggest that, for patients presenting to an emergency department, pyrexia often indicates infection that may necessitate admission, especially in the elderly.