Clinically presenting acute/subacute ischemic stroke: differential diagnosis of the non-enhanced CT hypodensity by advanced neuroimaging

Feasibility of CT attenuation values in distinguishing acute ischemic stroke, old cerebral infarction and leukoaraiosis

PURPOSE

This study aimed to investigate the feasibility of using computed tomography (CT) attenuation values to differentiate hypodense brain lesions, specifically acute ischemic stroke (AIS) from asymmetric leukoaraiosis (LA) and old cerebral infarction (OCI).

MATERIALS AND METHODS

This retrospective study included patients with indeterminate hypodense lesions identified via brain CT scans conducted between June 2019 and June 2021. All lesions were confirmed through head MRI/diffusion-weighted imaging within 48 h after CT. CT attenuation values of hypodense lesions and symmetrical control regions were measured. Additionally, CT attenuation value difference (ΔHU) and ratio (RatioHU) were calculated. One-way analysis of variance (ANOVA) was used to compare age and CT parameters (CT attenuation values, ΔHU and RatioHU) across the groups. Finally, receiver operating characteristic (ROC) analysis was performed to determine the cutoff values for distinguishing hypodense lesions.

RESULTS

A total of 167 lesions from 146 patients were examined. The CT attenuation values for AIS(n = 39), LA(n = 53), and OCI(n = 75) were 18.90 ± 6.40 HU, 17.53 ± 4.67 HU, and 11.90 ± 5.92 HU, respectively. The time interval between symptom onset and CT scans for AIS group was 32.21 ± 26.85 h. ANOVA revealed significant differences among the CT parameters of the hypodense lesion groups (all P < 0.001). The AUC of CT values, ΔHU, and RatioHU for distinguishing AIS from OCI were 0.802, 0.896 and 0.878, respectively (all P < 0.001). Meanwhile, the AUC for distinguishing OCI from LA was 0.789, 0.883, and 0.857, respectively (all P < 0.001). Nevertheless, none of the parameters could distinguish AIS from LA.

CONCLUSION

CT attenuation parameters can be utilized to differentiate between AIS and OCI or OCI and LA in indeterminate hypodense lesions on CT images. However, distinguishing AIS from LA remains challenging.

Effect of plasma thrombin-antithrombin complex on ischemic stroke: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Thrombin-antithrombin complex (TAT) is a prethrombotic marker, and its application in ischemic stroke is still uncertain. The purpose of this systematic review and meta-analysis is to evaluate the relationship between plasma TAT and ischemic stroke base on the current evidence.

METHODS

A systematic literature search was conducted for searching the relative studies that investigated the association of TAT and ischemic stroke in PubMed, EMBASE, and Cochrane library databases. Mean difference and 95% confidence interval as the effect sizes were synthesized by random effects model in Review Manager (RevMan) Version 5.4. The heterogeneity was investigated using the chi-square test and the possible sources of heterogeneity were explored by sensitivity analysis and meta-regression. The publication bias was estimated by Egger's tests.

RESULTS

A total of 12 eligible studies were included involving 1431 stroke cases and 532 healthy controls, of which six studies were eventually included in the meta-analysis. Plasma TAT in patients with ischemic stroke was significantly higher than that in healthy controls (MD 5.31, 95% CI = 4.12-6.51, P < 0.0001, I² = 97.8%). There is a difference of TAT level in the same period among cardioembolic, lacunar, and atherothrombotic stroke (all P < 0.0001), in which the cardioembolic stroke with the highest level. Meanwhile, it is significant of TAT levels among various phases of cardioembolic stroke and the acute phase are markedly elevated (MD 7.75, 95CI%, 6.07-9.43, P < 0.001). However, no difference was found in the atherothrombotic (P = 0.13) and lacunar stroke (P = 0.34). Besides, the higher TAT level is closely related to the poor prognosis of patients with ischemic stroke, including higher recurrence, mortality, unfavorable recovery (modified Rankin scale > 2), and poor revascularization.

CONCLUSIONS

This study suggested that plasma TAT levels are different in ischemic stroke subtypes, which are closely associated with the progression and might have an effect on the prognosis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD: 42021248787.

Plain Computed Tomography With Spectral Imaging Findings of Early Cerebral Ischemia

PURPOSE

To investigate the findings of plain spectral computed tomography (CT) with multiparameter of early cerebral ischemia.

PATIENTS AND METHODS

Thirty-three patients with suspected early cerebral ischemia who received a one-stop CT examination (plain scan with spectral CT imaging mode, CTP and CTA) of the brain were enrolled in this study. No clear lesion was observed in any patient on the plain CT. However, the CTA displayed evidence of vascular stenosis and the CTP displayed a corresponding low perfusion area consistent with early cerebral ischemia. Regions of interest were placed in the abnormal perfusion regions and the contralateral symmetric regions on plain CT. Then, the CT value of the monochromatic images (70 kV), the slope of the spectral HU curve, blood (iodine), iodine (water), and water (iodine) concentrations were measured. A paired t-test was performed for data comparison. The receiver operating characteristic curve was used to evaluate diagnostic performance.

RESULTS

The CT values of the ischemic regions at 70 keV, the spectral HU curve, water, and blood values of the ischemic measurements were slightly lower than those of the contralateral symmetric regions (P < .05). Monochromatic images at 70 keV had the highest area under the curve value, and the sensitivity and specificity were 90.0% and 63.0%, respectively.

CONCLUSION

The difference of monochromatic CT values, spectral HU curve, and basic material concentrations between the early cerebral ischemia region and the contralateral symmetric region on spectral CT imaging may provide a reference with the diagnosis of early cerebral ischemia.

The "Air in the CT X-ray Tube Oil" Artifact-Examples of the Quality Control Images and the Evaluation of Four Potential Clinical Patients' Head Computed Tomography Cases

We present a newly reposted scanner-based artifact-with 4 potential patients' head computed tomography (CT) cases-the "Air in the CT X-ray Tube Oil" artifact with a 64-slice multidetector CT. This artifact mimics diseases, which cause hypodense findings in CT images. It can be difficult to notice in the clinical patient imaging but can be also very difficult to verify in quality control tests.