Differentiation between Cerebral Hemorrhage and Contrast Extravasation Using Dual Energy Computed Tomography after Intra-Arterial Neuro Interventional Procedures

Dual-energy Computed Tomography (DECT) predicts the efficacy of contrast medium extravasation and secondary cerebral hemorrhage after stent thrombectomy in acute ischemic cerebral infarction

 To prospective research the efficacy of dual-energy computed tomography (DECT) in predicting contrast medium extravasation and secondary cerebral hemorrhage after stent thrombectomy in acute ischemic cerebral infarction. Ninety-two patients with acute ischemic stroke who underwent intra-arterial thrombolysis in our hospital from December 2019 to January 2022 have opted as the study subjects. DECT was performed immediately after stent thrombectomy. Images were generated through the image workstation and routine diagnosis was performed 24 hours after the operation. To analyze the diagnostic value of To analyze the diagnostic value of DECT, and to explore the diagnostic status of lesions with hemorrhagic transformation or increased hemorrhage and their correlation with iodine concentration. (1) 68 situations were confirmed, 56 positive and 12 negative with detection rates of 10.71% for hemorrhage, 75.00% for contrast agent extravasation, and 14.29% for extravasation combined with hemorrhage; (2) DECT diagnosed 8 cases of postoperative bleeding and 44 cases of extravasation of contrast media and 4 cases of extravasation of contrast media with hemorrhage ; The accuracy of DECT in diagnosing postoperative hemorrhage was 96.43%. The accuracy of diagnosis of extravasation was 96.43%. (3) The mean iodine concentration of lesions with increased hemorrhage or hemorrhagic transformation was higher compared to those without; (4) There was a correlation between hemorrhagic transformation or increased hemorrhage and iodine concentration. Dual-energy CT (DECT) can accurately distinguish the extravasation of contrast agent and secondary cerebral hemorrhage, and can predict the increased bleeding and bleeding transformation, with good diagnostic value and good predictive efficacy.

Discrimination of Hemorrhage and Contrast Media in a Head Phantom on Photon-Counting Detector CT Data

In this anthropomorphic head phantom study, samples containing blood and contrast agent with concentrations ranging from 0 to 6 mg iodine per milliliter and another set of samples without blood for reference were scanned with a photon-counting detector CT using a standard cranial protocol. It was demonstrated that photon-counting detector CT can reliably distinguish hemorrhage and contrast media, including density determination of the latter. The technology promises to add value in several neuroimaging applications.

Diagnostic accuracy of dual-energy computed tomography in the diagnosis of neurological complications after endovascular treatment of acute ischaemic stroke: a systematic review and meta-analysis

OBJECTIVES

To investigate dual-energy computed tomography's (DECT) diagnostic performance in detecting neurological complications following endovascular therapy (EVT) of acute ischaemic stroke (AIS).

METHODS

We performed the literature search using Web of Science, Scopus, PubMed, EBSCO, and Science Direct databases for published related studies. The selected studies estimated the validity of DECT in the detection of neurological complications after EVT for AIS. Study quality assessment was performed utilizing the Quality of Diagnostic Accuracy Studies-2 Tool. Our meta-analysis calculated the pooled sensitivity, negative likelihood ratio, specificity, and positive likelihood ratio for each detected complication. The summary receiver operating characteristics (sROC) curve was utilized to estimate the area under the curve (AUC).

RESULTS

Of 22 studies, 21 were included in the quantitative synthesis. In the detection of intracerebral haemorrhage (ICH), DECT pooled overall sensitivity and specificity were 69.9% (95% CI, 44.5%-86.8%) and 100% (95% CI, 92.1%-100%); whereas, in the detection of ischaemia, they were 85.9% (95% CI, 80.4%-90%) and 90.7% (95% CI, 87%-93.5%), respectively. On the sROC curve, AUC values of 0.954 and 0.952 were recorded for the detection of ICH and ischaemia, respectively.

CONCLUSIONS

DECT demonstrated high accuracy and specificity in the detection of neurological complications post-endovascular treatment of AIS. However, further prospective studies with a standardized reference test and a larger sample size are recommended to support these findings.

ADVANCES IN KNOWLEDGE

DECT is a rapid and valid imaging tool for the prediction of ICH and cerebral ischaemia after the EVT of AIS.

Prognostic value of contrast staining on dual-energy CT after endovascular therapy in acute ischemic stroke: a meta-analysis

BACKGROUND

Contrast staining (CS) on dual-energy CT (DECT) is common after endovascular therapy (EVT) in acute ischemic stroke (AIS). We performed a meta-analysis to investigate the prognostic significance of CS detected by DECT after EVT in AIS.

METHOD

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science and Scopus databases were searched from inception to July 2023 for publications on the prognostic significance of CS on DECT after EVT in patients with AIS. Prognostic outcomes were hemorrhage transformation (HT) and poor functional outcome (modified Rankin Scale [mRS] Score of 3-6 at the 90-day follow-up). Data are presented as odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Eleven studies including 1123 cases of AIS were included. Pooled results indicated a higher risk of HT in patients with CS than in those without CS (OR = 2.22; 95% CI 1.41-3.51, P = 0.001; I2 = 45.4%). No association between CS and symptomatic HT was observed (OR = 2.10; 95% CI 0.64-6.95, P = 0.223; I2 = 67.3%). Moreover, there was also higher odds of poor functional outcome in patients with CS than in those without CS (OR = 2.76; 95% CI 1.53-4.97, P = 0.001; I2 = 44.9%).

CONCLUSIONS

The presence of contrast staining on DECT after EVT is associated with a higher risk of hemorrhage transformation and poor functional outcome. However, further high-quality studies with standardized processes are required to confirm these results.

Dual Source Photon-Counting Computed Tomography-Part II: Clinical Overview of Neurovascular Applications

Photon-counting detector (PCD) is a novel computed tomography detector technology (photon-counting computed tomography-PCCT) that presents many advantages in the neurovascular field, such as increased spatial resolution, reduced radiation exposure, and optimization of the use of contrast agents and material decomposition. In this overview of the existing literature on PCCT, we describe the physical principles, the advantages and the disadvantages of conventional energy integrating detectors and PCDs, and finally, we discuss the applications of the PCD, focusing specifically on its implementation in the neurovascular field.

Hemorrhagic Transformation Rates following Contrast Media Administration in Patients Hospitalized with Ischemic Stroke

BACKGROUND AND PURPOSE

Hemorrhagic transformation is a critical complication associated with ischemic stroke and has been associated with contrast media administration. The objective of our study was to use real-world in-hospital data to evaluate the correlation between contrast media type and transformation from ischemic to hemorrhagic stroke.

MATERIALS AND METHODS

We obtained data on inpatient admissions with a diagnosis of ischemic stroke and a record of either iso-osmolar or low-osmolar iodinated contrast media for a stroke-related diagnostic test and a treatment procedure (thrombectomy, thrombolysis, or angioplasty). We performed multivariable regression analysis to assess the relationship between contrast media type and the development of hemorrhagic transformation during hospitalization, adjusting for patient characteristics, comorbid conditions, procedure type, a threshold for contrast media volume, and differences across hospitals.

RESULTS

Inpatient visits with exclusive use of either low-osmolar (n = 38,130) or iso-osmolar contrast media (n = 4042) were included. We observed an overall risk reduction in hemorrhagic transformation among patients who received iso-osmolar compared with low-osmolar contrast media, with an absolute risk reduction of 1.4% (P = .032), relative risk reduction of 12.5%, and number needed to prevent harm of 70. This outcome was driven primarily by patients undergoing endovascular thrombectomy (n = 9211), in which iso-osmolar contrast media was associated with an absolute risk reduction of 4.6% (P = .028), a relative risk reduction of 20.8%, and number needed to prevent harm of 22, compared with low-osmolar contrast media.

CONCLUSIONS

Iso-osmolar contrast media was associated with a lower rate of hemorrhagic transformation compared with low-osmolar contrast media in patients with ischemic stroke.

Diagnostic accuracy of dual-energy computed tomography to differentiate intracerebral hemorrhage from contrast extravasation after endovascular thrombectomy for acute ischemic stroke: systematic review and meta-analysis

OBJECTIVES

To assess whether dual-energy computed tomography (DECT), using conventional computed tomography or magnetic resonance imaging as a reference standard, is sufficiently accurate to differentiate intracerebral hemorrhage from contrast extravasation after endovascular thrombectomy for acute ischemic stroke.

METHODS

On January 20, 2021, we searched the PubMed Medline, Embase, Web of Science, and Cochrane Library databases. QUADAS-2 was used to assess the risk of bias and applicability. Meta-analyses were performed using a bivariate random-effects model. To explore sources of heterogeneity, meta-regression analyses were performed. Deeks' funnel plot asymmetry test was used to assess publication bias.

RESULTS

A total of 7 studies (269 patients, 269 focal areas) were included. The pooled mean sensitivity, specificity, and accuracy of DECT in identifying intracerebral hemorrhage from contrast extravasation after mechanical thrombectomy for acute ischemic stroke were 0.77 (95% confidence interval (CI) 0.29 to 0.96), 1 (95% CI 0.86 to 1), and 0.99 (95% CI 0.98 to 1), respectively. This evidence was of moderate certainty due to the risk of bias. Higgin's I-squared for study heterogeneity was observed for the pooled sensitivity (I² = 78.88%) and pooled specificity (I² = 82.12%). Moreover, Deeks' funnel plot asymmetry test revealed no publication bias (p = 0.38).

CONCLUSION

DECT shows excellent accuracy and specificity in differentiating intracerebral hemorrhage from contrast extravasation after endovascular thrombectomy for acute ischemic stroke. Nevertheless, there was substantial and moderate heterogeneity among the studies. Future large-scale, prospective cohort studies are warranted to validate our findings.

KEY POINTS

• Dual-energy computed tomography shows excellent accuracy and specificity in differentiating intracerebral hemorrhage from contrast extravasation after endovascular thrombectomy for acute ischemic stroke. • Via meta-regression analysis, we found various possible covariates, including the publication date, image analysis, index test time, time of follow-up imaging, and reference standard judgment, that had an important effect on the heterogeneity. • There were no concerns regarding applicability in any of the included studies.