Quantifying T 2 relaxation time changes within lesions defined by apparent diffusion coefficient in grey and white matter in acute stroke patients

Novel advanced imaging techniques for cerebral oedema

Cerebral oedema following acute ischemic infarction has been correlated with poor functional outcomes and is the driving mechanism of malignant infarction. Measurements of midline shift and qualitative assessment for herniation are currently the main CT indicators for cerebral oedema but have limited sensitivity for small cortical infarcts and are typically a delayed sign. In contrast, diffusion-weighted (DWI) or T2-weighted magnetic resonance imaging (MRI) are highly sensitive but are significantly less accessible. Due to the need for early quantification of cerebral oedema, several novel imaging biomarkers have been proposed. Based on neuroanatomical shift secondary to space-occupying oedema, measures such as relative hemispheric volume and cerebrospinal fluid displacement are correlated with poor outcomes. In contrast, other imaging biometrics, such as net water uptake, T2 relaxometry and blood brain barrier permeability, reflect intrinsic tissue changes from the influx of fluid into the ischemic region. This review aims to discuss quantification of cerebral oedema using current and developing advanced imaging techniques, and their role in predicting clinical outcomes.

Effect of Optimized Emergency Care on Treatment Rate and Prognosis of Elderly Patients with Acute Stroke in Emergency Department: A Systematic Review and Meta-Analysis

Objective

This research was to detect the treatment rate and prognosis of elderly patients with acute stroke in emergency department by the optimization of emergency care applying meta-analysis.

Methods

The online databases including PubMed, EMBASE, ScienceDirect, Cochrane Library, China knowledge Network Database (CNKI), China VIP Database, Wanfang Database, and China Biomedical Literature Database (CBM) were searched. The retrieval time limit was set from the establishment of the database to the present. The data were extracted independently by two investigators. The bias of per publication was assessed following Cochrane manual 5.1.0 standard. RevMan5.4 statistical software was used to analyze the collected data by meta.

Results

The 8 randomized controlled trials included in this meta-analysis all reported patients' baseline status. The meta-analysis of the rescue time of the study group and the control group (CH2 = 1507.80, df = 4, P ≤ 0.001, and I2 = 100%) showed that the emergency nursing with optimized emergency procedures can shorten the rescue of elderly acute stroke patients in the emergency department time. There are 6 literatures reporting the case fatality rate (Chi2 = 1.12, df = 5, P = 0.95 > 0.05, and I2 = 0%), and the death rate of the study group was not higher than that of the control group (Z = 4.4 and P < 0.0001). The use of optimized first aid can reduce mortality in elderly patients with acute stroke. Six articles on disability rate reported the heterogeneity of disability rate (CH2 = 2.88, df = 5, P = 0.72 > 0.05, and I2 = 0%), indicating that the disability rate in the study group was lower than that in the control group (Z = 3.91 and P < 0.0001), indicating that emergency nursing by optimizing emergency procedures can reduce the disability rate of elderly stroke patients in emergency department.

Conclusion

Optimizing the emergency care process can effectively improve the emergency rate and prognosis of elderly patients with acute stroke in emergency department; however, further research with higher methodological quality and longer intervention time are needed to verify later.

A Comparison of T2 Relaxation-Based MRI Stroke Timing Methods in Hyperacute Ischemic Stroke Patients: A Pilot Study

Background:

T₂ relaxation-based magnetic resonance imaging (MRI) signals may provide onset time for acute ischemic strokes with an unknown onset. The ability of visual and quantitative MRI-based methods in a cohort of hyperacute ischemic stroke patients was studied.

Methods:

A total of 35 patients underwent 3T (3 Tesla) MRI (<9-hour symptom onset). Diffusion-weighted (DWI), apparent diffusion coefficient (ADC), T₁-weighted (T₁w), T₂-weighted (T₂w), and T₂ relaxation time (T₂) images were acquired. T₂-weighted fluid attenuation inversion recovery (FLAIR) images were acquired for 17 of these patients. Image intensity ratios of the average intensities in ischemic and non-ischemic reference regions were calculated for ADC, DWI, T₂w, T₂ relaxation, and FLAIR images, and optimal image intensity ratio cut-offs were determined. DWI and FLAIR images were assessed visually for DWI/FLAIR mismatch.

Results:

The T₂ relaxation time image intensity ratio was the only parameter with significant correlation with stroke duration (r = 0.49, P = .003), an area under the receiver operating characteristic curve (AUC = 0.77, P < .0001), and an optimal cut-off (T₂ ratio = 1.072) that accurately identified patients within the 4.5-hour thrombolysis treatment window with sensitivity of 0.74 and specificity of 0.74. In the patients with the additional FLAIR, areas under the precision-recall-gain curve (AUPRG) and F₁ scores showed that the T₂ relaxation time ratio (AUPRG = 0.60, F₁ = 0.73) performed considerably better than the FLAIR ratio (AUPRG = 0.39, F₁ = 0.57) and the visual DWI/FLAIR mismatch (F₁ = 0.25).

Conclusions:

Quantitative T₂ relaxation time is the preferred MRI parameter in the assessment of patients with unknown onset for treatment stratification.