Multi-site laser Doppler flowmetry for assessing collateral flow in experimental ischemic stroke: Validation of outcome prediction with acute MRI

High variability in infarct size is common in experimental stroke models and affects statistical power and validity of neuroprotection trials. The aim of this study was to explore cerebral collateral flow as a stratification factor for the prediction of ischemic outcome. Transient intraluminal occlusion of the middle cerebral artery was induced for 90 min in 18 Wistar rats. Cerebral collateral flow was assessed intra-procedurally using multi-site laser Doppler flowmetry monitoring in both the lateral middle cerebral artery territory and the borderzone territory between middle cerebral artery and anterior cerebral artery. Multi-modal magnetic resonance imaging was used to assess acute ischemic lesion (diffusion-weighted imaging, DWI), acute perfusion deficit (time-to-peak, TTP), and final ischemic lesion at 24 h. Infarct volumes and typology at 24 h (large hemispheric versus basal ganglia infarcts) were predicted by both intra-ischemic collateral perfusion and acute DWI lesion volume. Collateral flow assessed by multi-site laser Doppler flowmetry correlated with the corresponding acute perfusion deficit using TTP maps. Multi-site laser Doppler flowmetry monitoring was able to predict ischemic outcome and perfusion deficit in good agreement with acute MRI. Our results support the additional value of cerebral collateral flow monitoring for outcome prediction in experimental ischemic stroke, especially when acute MRI facilities are not available

Accuracy of stereotactic localisation with magnetic resonance compared to CT scan : experimental findings

BACKGROUND: Stereotactic localisation of proper targets can be obtained with Magnetic Resonance imaging (MRI), pending correction of the well-known inaccuracy of MRI in reproducing exact geometrical dimension. The aim of the experimental work was to determine the real extent of the MRI distortion and to correct it. METHODS: PVC phantoms and fixed human brains were used as target simulators: stereotactic targeting was obtained with CT and MRI: the results were compared and, finally, the real stereotactic values were measured on a commercial stereotactic device. To optimise MRI targeting it was necessary to abate the "chemical-shift", to modify the head-coil receiver (tuning the "off-resonance" frequencies) and to correct the targeting directly on the images (especially for the Y axis values); careful quality control and environmental tests were also necessary to maintain good performances along the time. RESULTS: 172 measurements were carried out using both CT, plain X-ray and MRI on PVC phantom. The values obtained from CT were considered as reference. Significant geometrical accuracy was found with CT targeting, except for the Z co-ordinate, due to the slice thickness. Mean value differences between the targets on MRI and their real geometric position are about 1 mm on X and Z axises and about 2 mm on Y axis. Similar results were obtained on fixed brains, where absolute values of X and Y co-ordinates of the simulators were measured using a millimetre grid placed over the brain slice. INTERPRETATION: Experimental findings concerning stereotactic targeting with MRI suggest accuracy adequate for clinical practice, even when extreme geometrical precision is required, such as in radiosurgery or functional stereotaxy. Careful quality control and intensive experimental setting of the MRI device are mandatory to obtain satisfactory results

Intracerebral hemorrhage in intensive care unit : early prognostication fallacies. A single center retrospective study

BACKGROUND: Intracerebral hemorrhage (ICH) admitted to intensive care is deem of poor prognosis. To compare observed and predicted 30-days mortality and to evaluate long term functional outcome in a consecutive ICH cohort. METHODS: Retrospective analysis of prospectively collected data of ICH patients managed in a Neuro-ICU from 2012 to 2015. RESULTS: 136 consecutive patients; 34 (25%) had "withholding of life-sustaining treatment" (WLST) order and 102 (75%) received a "full treatment" (FT). WLST cohort: median (IQR): 72 (70-77) years old, Glasgow Coma Scale (GCS) 4 (3-4) at admission, ICH volume 114 cm3 (68- 152); all patients died during neuro-ICU recovery, 28 (82%) patients had brain death diagnosis and 15 (54%) of these were organ donors. FT cohort: 67 (51-73) years old, GCS 9 (6-12) at admission, ICH volume 46 (24-90) cm3, neurosurgery for clot removal in 65 (64%) (p 3 in 64 (65%). Neurosurgery for clot removal was associated with a lower 30 and 180-days mortality (p=0.0005 and p=0.0268, respectively) and along with GCS at admission it was an independent significant prognostic factor. CONCLUSIONS: Mortality and functional outcome is less severe than predicted in patients with ICH receiving a full medical and/or surgical treatmen