Neuroimaging Modalities Used for Ischemic Stroke Diagnosis and Monitoring

Rapid synergistic thrombolysis of ischemic stroke guided by high-resolution and high-speed photoacoustic cerebrovascular imaging

Thrombosis is the major cause of ischemic stroke and poses a serious health burden globally. Current thrombolytic strategies, such as systematic administration of recombinant human tissue plasminogen activator (rt-PA), are challenged by limited thrombolysis efficiency due to low targeting ability and a short plasma half-life. Here, we report a rapid synergistic strategy that integrates sonothrombolysis and rt-PA mediated pharmacological thrombolysis to achieve accurate and efficient treatment of ischemic stroke. The strategy (PLPA@PFP) uses a platelet-biomimetic membrane as a carrier to deliver both perfluoropentane (PFP) and rt-PA, prolonging half-life and effectively accumulating at the thrombus within 0.5 hours. Upon exposure to focused ultrasound, PFP-based cavitation effects significantly enhance thrombus breakdown and rt-PA penetration, enabling synergistic sono/pharmacological thrombolysis both in vitro and in vivo. High-resolution photoacoustic (PA) imaging provides direct assessment of vascular reperfusion following therapeutic intervention in a murine model of ischemic stroke, offering important guidance for clinical treatment.

Effect of tranexamic acid on rebleeding, mortality, and hydrocephalus in patients with aneurysmal subarachnoid hemorrhage: A systematic review and meta-analysis

BACKGROUND

The therapeutic benefit of tranexamic acid (TXA) in patients with aneurysmal subarachnoid hemorrhage (aSAH) remains controversial. We evaluated the efficacy and safety of TXA in aSAH patients by performing a comprehensive meta-analysis of randomized controlled trials (RCTs).

METHODS

We conducted a systematic review and meta-analysis of RCTs comparing TXA with either placebo or standard care in aSAH patients. A comprehensive literature search was performed across PubMed, EMBASE, Web of Science, Cochrane Library, and Scopus from inception to July 2024. Outcomes of interest included rebleeding, mortality, functional outcomes, and delayed cerebral ischemia (DCI). Subgroup analyses were performed based on publication date and TXA administration duration.

RESULTS

Thirteen RCTs were included in our study. TXA significantly reduced rebleeding rates (relative risk [RR] 0.61; 95 % confidence interval [CI] 0.51-0.74, P < 0.00001) but did not affect mortality (RR 0.99; 95 % CI 0.86-1.13, P = 0.84) or good clinical outcomes (RR 0.98; 95 % CI 0.93-1.05, P = 0.63). TXA use was associated with increased occurrence of hydrocephalus (RR 1.12; 95 % CI 1.01-1.23, P = 0.03) but not DCI (RR 1.00; 95 % CI 0.84-1.20, P = 0.96). Subgroup analyses suggested greater rebleeding reduction with longer TXA administration (≥1 week) and in more recent studies (post-2000).

CONCLUSIONS

TXA reduces rebleeding in aSAH but does not improve survival or functional outcomes. Its routine use in aSAH is not supported by current evidence.

Non-Contrast MRI Sequences for Ischemic Stroke: A Concise Overview for Clinical Radiologists

Ischemic stroke is the second leading cause of mortality and morbidity worldwide. Due to the urgency of implementing immediate therapy, acute stroke necessitates prompt diagnosis. The current gold standards for vascular imaging in stroke include computed tomography angiography (CTA), digital subtraction angiography (DSA) and magnetic resonance angiography (MRA). However, the contrast agents used in these methods can be costly and pose risks for patients with renal impairment or allergies. The aim of this paper is to provide a comprehensive overview of current MRI techniques and sequences for evaluating ischemic stroke, emphasizing the importance of non-contrast options and their clinical implications for radiologists in the diagnosis and management of ischemic stroke. Standard MRI sequences-such as T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), fluid-attenuated inversion recovery (FLAIR), diffusion-weighted imaging (DWI), DWI-FLAIR mismatch, and apparent diffusion coefficient (ADC)-are essential for determining infarct location, volume, and age. Additionally, incorporating susceptibility-weighted imaging (SWI) sequence aids in identifying signs of hemorrhagic transformation within the infarcted region. Advanced techniques like arterial spin labeling (ASL) can serve as a non-contrast alternative for mapping cerebral blood flow (CBF) and allowing for comparison between infarcted and healthy brain areas. Adding ASL to the routine sequence allows ASL-DWI mismatch analysis that is useful for quantifying salvageable tissue volume and facilitate timely recanalization, while time-of-flight (TOF) MRA and magnetic resonance venography (MRV) help assess venous thrombosis, stenosis, or arterial occlusions. Finally, MR spectroscopy can provide insights into critical brain metabolites, including N-acetylaspartate (NAA), and lactate (Lac) to determine patient prognosis. Current MRI technology provides a myriad of sequence options for the comprehensive evaluation of ischemic stroke without the need for contrast material. A thorough understanding of the advantages and limitations of each sequence is crucial for its optimal implementation in diagnosis and treatment.

Diagnostic and Interventional Imaging in Various Diseases

Diagnostic and interventional imaging is a cornerstone in the management of cases in various medical and surgical domains, such as neonatology, neurology, neurosurgery, otorhinolaryngology, dentistry, gynecology and urology [...].

Predictors of anxiety in patients undergoing magnetic resonance imaging scans: a multicenter cross-sectional study

BACKGROUND

Magnetic resonance imaging (MRI) is a noninvasive diagnostic tool that is commonly used to visualize soft tissues and anatomical structures. Many patients who undergo MRI scans experience anxiety. This multicenter study was conducted to assess anxiety levels experienced by patients who underwent MRI scans in the Palestinian radiology departments and identify the risk factors associated with higher levels of anxiety experienced by the patients.

METHODS

This multicenter cross-sectional study was conducted in the radiology departments of different hospitals in the West Bank of Palestine using a questionnaire. The questionnaire collected different demographic data of the patients. A 100-mm visual analog scale (VAS) was used to assess the level of anxiety experienced by the patients who received MRI scans. The data were analyzed using SPSS version 28.

RESULTS

A total of 383 patients participated in this study. Of the patients, 255 (66.6%) reported experiencing low, moderate, or high anxiety levels during the MRI scan. The median anxiety was 20.0 with an interquartile range (IQR) of 0.0-50.0 as measured using the 100-mm VAS. Higher anxiety levels were reported by the patients who were female (p-value < 0.001), unemployed (p-value = 0.009), and did not receive an MRI scan before (p-value = 0.001). In addition, the patients who received pelvis scans reported higher levels of anxiety compared to those who received scans for upper extremities (p-value = 0.031), abdomen (p-value = 0.033), pelvis (p-value = 0.043), and lower extremities (p-value = 0.016). In addition, the patients who received scans for the head/neck reported higher levels of anxiety compared to the patients who received scans for the lower extremities (p-value = 0.021).

CONCLUSION

The findings of this study showed that a considerable proportion of the patients who received MRI scans in Palestinian hospitals experience anxiety. Radiologists and other decision-makers in the healthcare system should design effective measures to reduce anxiety and improve the experiences of patients who are female, unemployed, and those who are scheduled to receive MRI scans for the first time. Moreover, these interventions should particularly focus on the patients who are scheduled to receive scans for the pelvis and head/neck.

Predicting Short- and Long-Term Functional Outcomes Based on Serum S100B Protein Levels in Patients with Ischemic Stroke

BACKGROUND

Ischemic stroke is one of the leading causes of mortality and disability. The neuroimaging methods are the gold standard for diagnostics. Biomarkers of cerebral ischemia are considered to be potentially helpful in the determination of the etiology and prognosis of patients with ischemic stroke.

AIM

This study aimed to investigate the usefulness of serum S100B protein levels as a short- and long-term prognostic factor in patients with ischemic stroke.

STUDY DESIGN AND METHODS

The study group comprised 65 patients with ischemic stroke. S100B protein levels were measured by immunoenzymatic assay. Short-term functional outcome was determined by the NIHSS score on day 1 and the difference in the NIHSS scores between day 1 and day 9 (delta NIHSS). Long-term outcome was assessed by the modified Rankin Scale (MRS) at 3 months after the stroke. At the end of the study, patients were divided into groups based on the NIHSS score on day 9 (0-8 "good" and >8 "poor"), the delta NIHSS ("no improvement" ≤0 and >0 "improvement"), and the MRS ("good" 0-2 and >2 "poor"). Differences in S100B levels between groups were analyzed with the ROC curve to establish the optimal cut-off point for S100B. The odds ratio was calculated to determine the strength of association. Correlations between S100B levels at three time points and these variables were evaluated.

RESULTS

We revealed a statistically significant correlation between S100B levels at each measurement point (<24 h, 24-48 H, 48-72 h) and the NIHSS score on day 9 (R Spearman 0.534, 0.631, and 0.517, respectively) and the MRS score after 3 months (R Spearman 0.620, 0.657, and 0.617, respectively). No statistically significant correlation was found between S100B levels and the delta NIHSS. Analysis of the ROC curve confirmed a high sensitivity and specificity for S100B. The calculated AUC for the NIHSS on day 9 were 90.2%, 95.0%, and 82.2%, respectively, and for the MRS, 83.5%, 83.4%, and 84.0%, respectively. After determining the S100B cut-off, the odds ratio for beneficial effect (NIHSS ≤ 8 at day 9 or MRS 0-2 after 3 months) was determined for each sampling point.

CONCLUSION

S100B is a useful marker for predicting short- and long-term functional outcomes in patients with ischemic stroke.