Cerebral thromboembolism: value of susceptibility-weighted imaging in the initial diagnosis of acute infarction

Neuroinflammation-associated miR-106a-5p serves as a biomarker for the diagnosis and prognosis of acute cerebral infarction

BACKGROUND

Acute cerebral infarction (ACI) is a common cerebrovascular disease. Previous studies have shown that some abnormally expressed microRNAs (miRNAs) play important roles in ACI. This study aimed to investigate the role of miR-106a-5p in the diagnosis and prognosis of ACI patients, and analyze the regulatory potential of miR-106a-5p on the inflammation of BV-2 microglial cells.

METHOD

Serum and cerebrospinal fluid (CSF) samples were collected from 98 ACI patients, and the expression of serum miR-106a-5p was analyzed using qRT-PCR. A receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic value of miR-106a-5p. The association of miR-106a-5p with ACI prognosis was evaluated using the logistic analysis. In vitro experiments were performed in BV-2 cells by oxygen glucose deprivation (OGD) treatment, and the effects of miR-106a-5p on BV-2 inflammation were assessed using an enzyme linked immunosorbent assay (ELISA).

RESULT

It was observed that miR-106a-5p was significantly upregulated in the serum and CSF of ACI patients (all P < 0.001), and had considerable diagnostic accuracy. The highest serum miR-106a-5p was observed in severe ACI cases, and miR-106a-5p expression was significantly increased in unfavorable prognosis patients. Serum and CSF expression of miR-106a-5p was positively correlated with proinflammatory cytokines in ACI patients, and the inflammation of OGD-induced BV-2 cells was suppressed by miR-106a-5p reduction.

CONCLUSION

MiR-106a-5p is overexpressed in ACI patients and may serve as a diagnostic and prognostic biomarker for ACI. Furthermore, miR-106a-5p may be involved in ACI progression by regulating neuroinflammation.

The Predictive Value of Contrast-Enhanced Ultrasound Combined with Serum miR-124 Level in Acute Cerebral Infarction and Their Correlation with the Contrast Enhancement of Carotid Atherosclerotic Plaque

OBJECTIVE

To investigate the predictive value of contrast-enhanced ultrasound (CEUS) combined with serum miR-124 level in acute cerebral infarction (ACI) and their association with the contrast enhancement of carotid atherosclerotic plaque.

METHODS

Totally 60 patients diagnosed with ACI and 60 controls were included in the study. All the subjects had carotid atherosclerotic plaques, and all of them were examined by CEUS and were tested for serum miR-124 levels.

RESULTS

Time to peak (TTP) and mean transit time (MTT) in the ACI group were significantly shorter than those in the control group (P < 0.05), but the peak intensity ratio (PIR), the area under the curve (AUC), and relative expression levels of serum miR-124 were notably greater in the ACI group (P < 0.05). There were statistically significant differences in TTP, MTT, PIR, AUC, and serum miR-124 expression in patients with different cerebral infarct areas in the ACI group (P < 0.05). Besides, the sensitivity and specificity of serum miR-124 levels for the prediction of ACI were 71.67% and 90.00%, respectively, with a cut-off value of 1.52, and the sensitivity was 86.67% and specificity was 93.33% of CEUS combined with serum miR-124 in the prediction of ACI. The ACI group showed a higher proportion of grades 2 and 3 (P < 0.001). Pearson correlation analysis showed that the intraplaque contrast enhancement was negatively related to TTP and MTT but had a positive correlation with PIR, AUC, and serum miR-124 levels.

CONCLUSION

Grades 2 and 3 intraplaque contrast enhancement and serum miR-124 level of 1.52 had high sensitivity and specificity to predict ACI. Moreover, the CEUS parameters combined with serum miR-124 level could improve the performance in predicting ACI and had auxiliary value in evaluating the stability of carotid atherosclerotic plaques.

Current approaches and advances in the imaging of stroke

A stroke occurs when the blood flow to the brain is suddenly interrupted, depriving brain cells of oxygen and glucose and leading to further cell death. Neuroimaging techniques, such as computed tomography and magnetic resonance imaging, have greatly improved our ability to visualise brain structures and are routinely used to diagnose the affected vascular region of a stroke patient's brain and to inform decisions about clinical care. Currently, these multimodal imaging techniques are the backbone of the clinical management of stroke patients and have immensely improved our ability to visualise brain structures. Here, we review recent developments in the field of neuroimaging and discuss how different imaging techniques are used in the diagnosis, prognosis and treatment of stroke.

Summary: Stroke imaging has undergone seismic shifts in the past decade. Although magnetic resonance imaging (MRI) is superior to computed tomography in providing vital information, further research on MRI is still required to bring its full potential into clinical practice.

Plasma miR-409-3p promotes acute cerebral infarction via suppressing CTRP3

Abnormal expression of miR-409-3p has been found in several neurodevelopmental disorders, but whether it is dysregulated in the patients with acute cerebral infarction (ACI) has not been evaluated. The current study mainly focused on the clinical significance and the underlying mechanism of plasma miR-409-3p in the progression of ACI. The level of plasma miR-409-3p was determined in ACI patients (n = 80) and healthy controls (n = 30). Pearson correlation assay was performed to evaluate the association and cardiovascular risk factors. A receiver operating characteristic curve (ROC) was used to evaluate the diagnostic value of plasma miR-409-3p levels in patients with ACI. Dual luciferase reporter assay and western blot were performed to determine the possible target gene of miR-409-3p. Our data showed that the expression of plasma miR-409-3p in the ACI group was higher than that in the healthy controls. Furthermore, Pearson correlation analysis indicated a positive correlation between plasma miR-409-3p and the NIHSS score. ROC analysis indicated that plasma miR-409-3p could differentiate plasma miR-409-3p in ACI patients from healthy controls. Then, we explored the possible target genes of miR-409-3p. Interestingly, C1q and TNF-related 3 (CTRP3), a novel adipose tissue-derived secreted factor, was found to be a target gene of miR-409-3p. We found that knockdown of CTRP3 significantly induced PC12 cell apoptosis, even in PC12 cells transfected with miR-409-3p inhibitor. These data suggested that miR-409-3p induced PC12 cell apoptosis by targeting CTRP3. Altogether, elevated plasma miR-409-3p is correlated with disease severity and may be efficient for the early diagnosis of ACI.

Detection of vessel wall calcifications in vertebral arteries using susceptibility weighted imaging

PURPOSE

Calcification of the brain supplying arteries has been linked to an increased risk for cerebrovascular disease. The purpose of this study was to test the potential of susceptibility weighted MR imaging (SWMR) for the detection of vertebral artery calcifications, based on CT as a reference standard.

METHODS

Four hundred seventy-four patients, who had received head CT and 1.5 T MR scans with SWMR, including the distal vertebral artery, between January 2014 and December 2016, were retrospectively evaluated and 389 patients were included. Sensitivity and specificity for the detection of focal calcifications and intra- and interobserver agreement were calculated for SWMR and standard MRI, using CT as a standard of reference. The diameter of vertebral artery calcifications was used to assess correlations between imaging modalities. Furthermore, the degree of vessel stenosis was determined in 30 patients, who had received an additional angiography.

RESULTS

On CT scans, 40 patients showed a total of 52 vertebral artery calcifications. While SWMR reached a sensitivity of 94% (95% CI 84-99%) and a specificity of 97% (95% CI 94-98%), standard MRI yielded a sensitivity of 33% (95% CI 20-46%), and a specificity of 93% (95% CI 90-96%). Linear regression analysis of size measurements confirmed a close correlation between SWMR and CT measurements (R ² = 0.74, p < 0.001). Compared to standard MRI (ICC = 0.52; CI 0.45-0.59), SWMR showed a higher interobserver agreement for calcification measurements (ICC = 0.84; CI 0.81-0.87).

CONCLUSIONS

For detection of distal vertebral artery calcifications, SWMR demonstrates a performance comparable to CT and considerably higher than conventional MRI.

Assessment of intracranial meningioma-associated calcifications using susceptibility-weighted MRI

PURPOSE

To determine the diagnostic accuracy of susceptibility-weighted MRI (SW-MRI) for the detection of intracranial meningioma-associated calcifications compared with standard MR sequences, using computed tomography (CT) as a reference standard.

MATERIALS AND METHODS

354 patients, who had received both a CT and a 1.5 Tesla clinical brain MRI with SW-MRI sequences between January 2014 and July 2016, were retrospectively evaluated and 316 patients were included. Calcification diameter was used to assess correlation between imaging modalities. Sensitivity and specificity as well as intra- and interobserver agreement were calculated for SW-MRI and standard MRI sequences when compared with reference standard CT.

RESULTS

Fifty patients had positive findings for intracranial meningioma-associated calcifications on CT scans. SW-MRI reached a sensitivity of 94% (95% confidence interval [CI]: 83-99%) and a specificity of 95% (95% CI: 92-98%) for the detection of meningioma-associated calcifications, while standard MRI yielded a sensitivity of 64% (95% CI: 49-77%) and a specificity of 94% (95% CI: 90-96%). Diameter measurements between SW-MRI and CT showed a close correlation (R²  = 0.99; P < 0.001) with a slight overestimation of size, which, however, did not reach significance level (SW-MRI: 8.2 mm ± 7.1; CT: 6.8 mm ± 6.4; P = 0.29). Compared with standard MRI, SW-MRI showed a better interobserver agreement for size measurements of calcifications.

CONCLUSION

SW-MRI enables a reliable detection of intracranial meningioma-associated calcifications by using CT as a reference and offers a higher diagnostic accuracy than standard MRI.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1177-1186.

Direct Thrombus Imaging in Stroke

There is an emergent need for imaging methods to better triage patients with acute stroke for tissue-plasminogen activator (tPA)-mediated thrombolysis or endovascular clot retrieval by directly visualizing the size and distribution of cerebral thromboemboli. Currently, magnetic resonance (MR) or computed tomography (CT) angiography visualizes the obstruction of blood flow within the vessel lumen rather than the thrombus itself. The present visualization method, which relies on observation of the dense artery sign (the appearance of cerebral thrombi on a non-enhanced CT), suffers from low sensitivity. When translated into the clinical setting, direct thrombus imaging is likely to enable individualized acute stroke therapy by allowing clinicians to detect the thrombus with high sensitivity, assess the size and nature of the thrombus more precisely, serially monitor the therapeutic effects of thrombolysis, and detect post-treatment recurrence. This review is intended to provide recent updates on stroke-related direct thrombus imaging using MR imaging, positron emission tomography, or CT.

Direct Imaging of Cerebral Thromboemboli Using Computed Tomography and Fibrin-targeted Gold Nanoparticles

Computed tomography (CT) is the current standard for time-critical decision-making in stroke patients, informing decisions on thrombolytic therapy with tissue plasminogen activator (tPA), which has a narrow therapeutic index. We aimed to develop a CT-based method to directly visualize cerebrovascular thrombi and guide thrombolytic therapy. Glycol-chitosan-coated gold nanoparticles (GC-AuNPs) were synthesized and conjugated to fibrin-targeting peptides, forming fib-GC-AuNP. This targeted imaging agent and non-targeted control agent were characterized in vitro and in vivo in C57Bl/6 mice (n = 107) with FeCl₃-induced carotid thrombosis and/or embolic ischemic stroke. Fibrin-binding capacity was superior with fib-GC-AuNPs compared to GC-AuNPs, with thrombi visualized as high density on microCT (mCT). mCT imaging using fib-GC-AuNP allowed the prompt detection and quantification of cerebral thrombi, and monitoring of tPA-mediated thrombolytic effect, which reflected histological stroke outcome. Furthermore, recurrent thrombosis could be diagnosed by mCT without further nanoparticle administration for up to 3 weeks. fib-GC-AuNP-based direct cerebral thrombus imaging greatly enhance the value and information obtainable by regular CT, has multiple uses in basic / translational vascular research, and will likely allow personalized thrombolytic therapy in clinic by a) optimizing tPA-dosing to match thrombus burden, b) enabling the rational triage of patients to more radical therapies such as endovascular clot-retrieval, and c) potentially serving as a theranostic platform for targeted delivery of concurrent thrombolysis.