Optimal Tissue Reperfusion Estimation by Computed Tomography Perfusion Post-Thrombectomy in Acute Ischemic Stroke

Background and Purpose: Modified Thrombolysis in Cerebral Infarction score (mTICI) ≥2b is defined as successful reperfusion. However, mTICI has rarely been correlated with dynamic perfusion imaging postendovascular therapy for acute stroke. We aimed to study the proportion of tissue optimal reperfusion (TOR) postendovascular therapy across different grades of mTICI. Methods: We conducted a single-center retrospective analysis of patients with acute ischemic strokes who had endovascular therapy between 2018 and 2019. Computer tomography perfusion or magnetic resonance perfusion was performed before and after endovascular therapy. Tmax+6 volume reduction of >90% was defined as TOR. Comparisons of proportions of TOR in different grades of mTICI were performed. In the present study, the requirement for informed consents was waived. Results: Eighty-two patients were included. The difference in the proportion of TOR for TICI categories was statistically significant (mTICI score 0, 0%, mTICI score 2A, 0%, mTICI score 2b, 50.0%, mTICI score 2c, 80.0%, mTICI score 3, 81.3%, χ 2 =14.035, P =0.003). Multivariable logistic regression showed that lower age (odds ratio, 0.932, P =0.017), onset-to-tissue plasminogen activator time (odds ratio, 0.980, P =0.005) and TOR (odds ratio, 8.764, P =0.031) were associated with favorable functional outcome. Conclusions: The proportion of TOR achieved by mTICI score of 2b was significantly lower than mTICI score of 2c and mTICI score of 3. TOR was associated with favorable functional outcome, and the degree of reperfusion was more strongly correlated with outcomes than the mTICI scores.

Brain perfusion in type 1 diabetes and cognitive dysfunction

The purpose. To evaluate brain microcirculation using contrast and non-contrast magnetic resonance perfusion in patients with type 1 diabetes and cognitive dysfunction.Material and methods. The study complies with generally accepted ethical rules. The study included 45 patients with type 1 diabetes and cognitive dysfunction and 20 patients without. Every patient included in the study was continuously monitoring glycemia with evaluation of variability coefficients. MRI was performed using a magnetic resonance imaging scanner Signa Creator “E”, GE Healthcare, 1.5 Tl, China: methods – dynamic contrast (“Gadovist”, w/w, bolusno, 5 ml) and arterial spin marks. SPSS Statistic software package was used for statistical analysis.Results. Blood flow decreased in patients with type 1 type and cognitive dysfunction in the areas of white and gray matter of frontal, occipital and temporal lobes, and shells (p ≤ 0.05). According to perfusion data, hyperglycemia and the following glycemic variability indices have the greatest influence on cortical structures: glycemic index of prolonged glycemia increase, risk of hyperglycemia and hypoglycemia, glycemic rate of change, glycemic control quality indicator, and in case of non-contrast glycemic control quality and glycemic rate of change, risks of hypo and hyperglycemia. The main factors of changes in brain microcirculation are episodes of severe hypoglycemia in the anamnesis, duration of the disease, arterial hypertension, high cholesterol levels. No separate markers for the evaluation of cognitive disturbances in type 1 diabetes were revealed.Conclusions. The basis of microcirculatory brain disorders in type 1 diabetes is the level of HbA1c and variability of glycemia as well as acute complications, duration of diabetes and associated conditions (arterial hypertension and hypercholesterolemia). The most important data were obtained during contrast perfusion.

Posterior fossa extra-axial variations of medulloblastoma: a pictorial review as a primer for radiologists

Manifestations of an atypical variant of medulloblastoma of the posterior fossa in extra-axial locations have been reported, and key questions concerning its interpretation have been raised previously. This review illustrated the clinico-radiological and histopathological features of the posterior fossa extra-axial medulloblastoma and described possible management strategies. We thoroughly reviewed all atypical anatomical locations of medulloblastoma reported within the posterior fossa and extra-axial spaces. The main characteristics of diagnostic imaging and histopathological results, primarily the distinctive radiopathological characteristics, were summarized to distinguish between intra- and extra-axial medulloblastoma, or pathologies mimicking this tumor. Most cases of posterior fossa extra-axial medulloblastoma have been reported in the cerebellopontine angle, followed by the tentorial and lateral cerebellar locations. The dural tail sign, which is commonly observed in meningioma, is rarely seen in intra- or extra-axial medulloblastoma and might be associated with other benign or malignant lesions. In addition to magnetic resonance imaging, the proposed new imaging techniques, including advances in modern neuroimaging modalities, were discussed, as potentially efficient modalities for characterizing extra-axial medulloblastoma. Radionuclide imaging and magnetic resonance perfusion imaging are practical alternatives to limit the number of differential diagnoses. We believe that medulloblastoma cases are likely under-reported because of publication bias and frequent tumors in unusual locations. Addressing these issues would help establish a more accurate understanding of this entity.

Options of neurovascularization in patients with type 2 diabetes mellitus using different methods of magnetic resonance perfusion

Objective. To evaluate neurovascularization using contrast and non-contrast magnetic resonance perfusion. Materials and methods. 140 patients with type 2 diabetes with and without cognitive impairment were included in the study. We assessed the variability of glycemia, magnetic resonance imaging (MRI): contrast and non-contrast. Results: brain neurovascularization change is associated with glycemia variability, with contrast advantage revealed in the contrast study. Microcirculation disorder occurs in both cortical (grey matter area) and subcortical structures. The greatest influence on brain vascularization disturbance in type 2 diabetes was revealed in terms of age, body mass index, arterial hypertension. Hyperglycemia and its duration, as well as hypoglycemia, control quality, average amplitude of oscillation, average time in the target range determined the change of vascularization. Conclusions. Understanding the pathogenesis of microcirculation disorders and the role of glycemia variability in the brain in type 2 diabetes, it is possible to correct the glycemic curve in time and eliminate modifiable risk factors (body mass index, arterial hypertension) affecting the development of cognitive disorders.