Study of correlations between CT properties of retrieved cerebral thrombi with treatment outcome of stroke patients.

BACKGROUND: All the patients with suspected stroke are directed to whole-brain CT scan. The purpose of this scan is to look for early features of ischemia and to rule out alternative diagnoses than stroke. In case of ischemic stroke, CT diagnostics (including CT angiography) is used mainly to locate the occlusion and its size, while the Hounsfield Units (HU) values of the thrombus causing the stroke are usually overlooked on CT scan or considered not important. The aim of this study was to demonstrate that the HU value is relevant and can help in better treatment planning. PATIENTS AND METHODS: There were 25 patients included in the study, diagnosed with ischemic stroke in the middle cerebral artery (MCA) territory. In all patients, systemic thrombolysis was not successful and the mechanical recanalization was needed. The retrieved thrombi were also analyzed histologically for the determination of red blood cells (RBC) proportion. CT of the proximal MCA (M1) segment was analyzed for average HU value and its variability both in the occluded section and the symmetrical normal site. These CT parameters were then statistically studied for the possible correlations with different clinical, histological and procedure parameters using the Linear Regression and the Pearson correlation coefficient. RESULTS: Relevant positive correlations were found between average HU value of thrombus and outcome modified Rankin Scale (mRS), initial mRS, number of passes with thrombectomy device as well as RBC proportion. CONCLUSIONS: Results of the present study suggest that measured HU values in CT images of the cerebral thrombi may help in the assessment of thrombus compaction and therefore better treatment planning.

Mechanical recanalization for acute bilateral cerebral artery occlusion - literature overview with a case.

Background Acute bilateral internal carotid artery (ICA) and/or middle cerebral artery (MCA) occlusion is extremely rare and associated with poor clinical outcomes. There are only a few reports in the literature about mechanical thrombectomy being performed for acute bilateral occlusions. The treatment strategies and prognoses (clinical outcomes) are therefore unclear. Methods A systematic review of the literature was performed through several electronic databases with the following search terms: acute bilateral stroke, mechanical recanalization and thrombectomy. Results In the literature, we identified five reports of six patients with bilateral ICA and/or MCA occlusion treated with mechanical recanalization. Additionally, we report our experience with a subsequent contralateral large brain artery occlusion during intravenous thrombolytic therapy, where the outcome after mechanical thrombectomy was not dependent on the time from stroke onset but rather on the capacity of collateral circulation exclusively. Conclusions Acute bilateral cerebral (ICA and/or MCA) occlusion leads to sudden severe neurological deficits (comas) with unpredicted prognoses, even when mechanical recanalization is available. As the collateral capacity seems to be more important than the absolute time to flow restoration in determining the outcomes, simultaneous thrombectomy by itself probably does not lead to improved functional outcomes.

Retrieved cerebral thrombi studied by T2 and ADC mapping: preliminary results.

Background Recent advances in MRI technology makes it increasingly more competitive to CT also in the field of interventions. Multi-parametric MRI offers a significant amount of data relevant for characterization of human cerebral thrombi. Patients and methods Cerebral thrombi of 17 patients diagnosed with acute stroke were acquired by mechanical thrombectomy. The thrombi were subsequently scanned using a high spatial-resolution 3D T1-weighted MRI to obtain morphological characteristics of the thrombi and also by apparent diffusion coefficient (ADC) and transversal nuclear magnetic resonance (NMR) relaxation time (T2) mapping. The MRI results were analysed for possible correlations between thrombectomy procedure parameters (recanalization time and number of passes) and MR-measurable parameters (sample-mean ADC and T2, within-sample coefficient of variation of ADC and T2, and thrombus length). Results Both MRI mapping techniques enabled a good discrimination among thrombi regions of different water mobility and compaction. Within-sample coefficient of variation of ADC was found most sensitive for discrimination between the thrombi where thrombectomy procedure was performed in a single pass and those where is was performed in two or more passes (p = 0.03). Interestingly, negative correlation was found between the recanalization time and thrombus length (ρ = -0.22). Conclusions Preliminary results of presented study shows that pretreatment MRI assessment of thrombi in stroke patients could potentially ease stroke treatment planning. In this study it is shown that within-sample coefficient of variation of ADC could serve for prediction of possible complications during thrombectomy procedures.