Single Phase Dual-energy CT Angiography: One-stop-shop Tool for Evaluating Aneurysmal Subarachnoid Hemorrhage

Dual-energy CT angiography in detecting underlying causes of intracerebral hemorrhage: an observational cohort study

BACKGROUND

CT angiography (CTA) is often used to detect underlying causes of acute intracerebral hemorrhage (ICH). Dual-energy CT (DECT) is able to distinguish materials with similar attenuation but different compositions, such as hemorrhage and contrast. We aimed to evaluate the diagnostic yield of DECT angiography (DECTA), compared to conventional CTA in detecting underlying ICH causes.

METHODS

All non-traumatic ICH patients who underwent DECTA (both arterial as well as delayed venous phase) at our center between January 2014 and February 2020 were analyzed. Conventional CTA acquisitions were reconstructed ('merged') from DECTA data. Structural ICH causes were assessed on both reconstructed conventional CTA and DECTA. The final diagnosis was based on all available diagnostic and clinical findings during one-year follow up.

RESULTS

Of 206 included ICH patients, 30 (14.6%) had an underlying cause as final diagnosis. Conventional CTA showed a cause in 24 patients (11.7%), DECTA in 32 (15.5%). Both false positive and false negative findings occurred more frequently on conventional CTA. DECTA detected neoplastic ICH in all seven patients with a definite neoplastic ICH diagnosis, whereas conventional CTA only detected four of these cases. Both developmental venous anomalies (DVA) and cerebral venous sinus thrombosis (CVST) were more frequently seen on DECTA. Arteriovenous malformations and aneurysms were detected equally on both imaging modalities.

CONCLUSIONS

Performing DECTA at clinical presentation of ICH may be of additional diagnostic value in the early detection of underlying causes, especially neoplasms, CVST and DVAs.

Comparative diagnostic efficacy of cranial CT, CTA, and DSA in subarachnoid hemorrhage management: A systematic review and meta-analysis

INTRODUCTION

Subarachnoid hemorrhage (SAH) is a critical medical condition associated with high morbidity and mortality rates. Timely and accurate diagnosis is crucial for optimal patient outcomes. Cranial computed tomography (CT), computed tomography angiography (CTA), and digital subtraction angiography (DSA) are commonly used imaging modalities for diagnosing SAH, but their comparative diagnostic efficacy remains debated.

METHODS

A systematic review and meta-analysis was conducted to evaluate the diagnostic performance of cranial CT, CTA, and DSA in identifying SAH. PubMed, Google scholar, Cochrane Library databases were searched for relevant studies published up to January 2024. Pooled sensitivity, specificity, and the summary receiver operating characteristic (SROC) curve were calculated using Review Manager 5.4.

RESULTS

A total of 31 studies involving 10,287 patients were included in the analysis. The pooled sensitivity of cranial CT for detecting SAH was 94.7 % (95 % Confidence Interval, CI) with a specificity of 98.3 % (95 % CI). CTA demonstrated a pooled sensitivity of 94.1 % (95 % CI) and specificity of 93.4 % (95 % CI). DSA showed a pooled sensitivity of 87.7 % (95 % CI) and specificity of 95.8 % (95 % CI). The SROC curve demonstrated discriminatory ability for all modalities.

CONCLUSION

Cranial CT, CTA, and DSA are valuable imaging modalities for diagnosing SAH, with high sensitivity and specificity. Cranial CT serves as an initial screening tool, while CTA offers superior sensitivity in detecting aneurysmal SAH. DSA remains essential in specific clinical scenarios. Further prospective studies are needed to validate these findings and refine diagnostic guidelines for SAH.

Dual-Energy Computed Tomography in the Evaluation and Management of Subarachnoid Hemorrhage, Intracranial Hemorrhage, and Acute Ischemic Stroke

Dual-energy computed tomography (DECT) has emerged as a valuable imaging modality in the diagnosis and management of various cerebrovascular pathologies, including subarachnoid hemorrhage, intracranial hemorrhage, and acute ischemic stroke. This article reviews the principles of DECT and its applications in the evaluation and management of these conditions. The authors discuss the advantages of DECT over conventional computed tomography, as well as its limitations, and provide an overview of current research and future directions in the field.

The diagnostic yield of repeat computed tomography angiography in cases of spontaneous subarachnoid haemorrhage after negative initial digital subtraction angiography

Purpose

It is currently unclear how useful repeat computed tomography angiography (CTA) is in spontaneous subarachnoid haemorrhage (SAH) patients after negative initial digital subtraction angiography (DSA). The purpose of this study is to assess the yield of repeat CTA for the detection of causative vascular lesions in patients with SAH in whom there has been a negative initial DSA.

Material and methods

This observational retrospective study was carried out from January 2013 to July 2022 at a single institution. Analysis of the SAH pattern on unenhanced CT showed that patients were divided into perimesencephalic SAH and diffuse SAH groups. A repeat CTA was performed on all spontaneous SAH patients who had a nega-tive initial CTA and DSA within a 2-week period. An interventional neuroradiologist and a diagnostic radiologist examined all images to search for causative vascular abnormalities.

Results

Forty-seven patients were included in our study, with a median age of 55 years and a range of 28-81 years. Thirty-seven had diffuse SAH (66%), and 16 had perimesencephalic SAH (34%). The repeat CTA revealed 2 causa-tive vascular lesions (a right PICA aneurysm and a mycotic aneurysm) in 2 separate patients (yield of 4.3%), both of whom had diffuse SAH (yield of 6.5%). In retrospect, none of these vascular lesions were evident in the initial CTA and DSA. No evidence of re-bleeding was observed in the follow-up period.

Conclusions

It is beneficial to repeat CTA when evaluating patients with diffuse SAH who initially present with nega-tive initial DSA. For occult aneurysms, the diagnostic yield of the follow-up CTA is 6.5%.

ASPECTS estimation using dual-energy CTA-derived virtual non-contrast in large vessel occlusion acute ischemic stroke: a dose reduction opportunity for patients undergoing repeat CT?

PURPOSE

Recent studies have shown the feasibility of dual-energy CT (DECT) virtual non-contrast (VNC) for determining infarct extent. In this study, patients presenting with large-vessel occlusion (LVO) acute ischemic stroke (AIS), we assess whether ASPECTS on DECTA-VNC differs from non-contrast CT (NCCT).

METHODS

After IRB approval, LVO-AIS patients undergoing NCCT and DECTA between October 2016 and September 2018 were retrospectively reviewed. DECTA-VNC images were derived using Syngo.via (Siemens, Erlangen, Germany). ASPECTS was scored by two blinded neuroradiologists. Square-weighted kappa statistic, diagnostic performance, Wilcoxon signed-rank tests between groups, and CT doses were calculated.

RESULTS

Fifty-one patients met inclusion criteria, with median age of 76 (IQR 67-82); 26/51 (51%) were female. Median time between last-known-well and CT was 120 min (IQR 60-252). DECTA-VNC ASPECTS score differed by ≤ 1 from consensus NCCT in 49/51 (96%) patients for reader 1 and in 46/51 (90%) for reader 2. ASPECTS on DECTA-SI and consensus NCCT differed by ≤ 1 in 45/51 (88%) for both readers. On a per ASPECTS-region basis, DECTA-VNC had 87% sensitivity, 95% specificity, 0.82% PPV, and 0.96% NPV. ASPECTS inter-rater agreement was highest for DECTA-VNC (κ = 0.71), DECTA-SI (κ = 0.48), and NCCT (κ = 0.40). NCCT median CTDIvol was 63.7 mGy (IQR 60.7-67.2); DLP was 1060.0 mGy·cm (IQR 981.0-1151.5). DECTA-VNC dose was lower: median CTDIvol was 20.9 mGy (IQR 19.8-22.2); DLP was 804.1 (IQR 691.6-869.4), p < 0.0001.

CONCLUSION

DECTA-derived VNC yielded similar ASPECTS scores as NCCT and is therefore non-inferior in early ischemia-related low attenuation edema/infarct detection in acute LVO-AIS patients. Further evaluation of the role of DECTA-VNC in AIS imaging is warranted.

Use of dual-energy computed tomography post endovascular treatment of cerebral aneurysm

Background:

Along with surgical clipping, endovascular management is one of the mainstay treatment options for cerebral aneurysms. However, immediate post procedural imaging is often hard to interpret due to the presence of contrast material. Dual-energy computed tomography (CT) allows differentiation between contrast extravasation and intracranial hemorrhage and this case illustrates the importance of this following endovascular treatment of an unruptured cerebral aneurysm.

Case Description:

A patient presented with acute ophthalmoplegia secondary to mass effect from an intracavernous ICA fusiform aneurysm. The patient underwent an endovascular flow diverting stent to treat this aneurysm. Post procedure, the patient had a reduced level of consciousness and underwent a conventional CT showing diffuse subarachnoid hyperdensity of the left hemisphere. Dual-energy CT allowed accurate differentiation and illustrated diffuse contrast material extravasation, allowing patient to continue on dual antiplatelets and therapeutic anticoagulation to reduce the risk of ischemic injury post endovascular stent.

Conclusion:

Use of dual-energy CT in the setting of endovascular management of intracranial aneurysms allows accurate diagnosis of any postoperative complications. Specifically, differentiating between subarachnoid hemorrhage and contrast extravasation is vital in these patients due to the significant consequences to their ongoing management in regard to continuation or cessation of antiplatelets or anticoagulation. With increasing access to this technology, its use should become standard practice in the post-operative investigation of these patients undergoing endovascular treatment.

Neuroimaging of Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) accounts for 10% to 20% of strokes worldwide and is associated with high morbidity and mortality rates. Neuroimaging is indispensable for rapid diagnosis of ICH and identification of the underlying etiology, thus facilitating triage and appropriate treatment of patients. The most common neuroimaging modalities include noncontrast computed tomography (CT), CT angiography (CTA), digital subtraction angiography, and magnetic resonance imaging (MRI). The strengths and disadvantages of each modality will be reviewed. Novel technologies such as dual-energy CT/CTA, rapid MRI techniques, near-infrared spectroscopy, and automated ICH detection hold promise for faster pre- and in-hospital ICH diagnosis that may impact patient management.

D-dimer may predict poor outcomes in patients with aneurysmal subarachnoid hemorrhage: a retrospective study

Serum biomarkers may play a reliable role in predicting the outcomes of patients with aneurysmal subarachnoid hemorrhage. This study retrospectively analyzed the relationship between serum biomarkers on admission and outcomes in patients with aneurysmal subarachnoid hemorrhage. We recruited 146 patients with aneurysmal subarachnoid hemorrhage who were treated in Renmin Hospital of Wuhan University of China between 1 May 2014 and 30 March 2016. There were 57 males and 89 females included and average age of included patients was 57.03 years old. Serum samples were taken immediately on admission (within 48 hours after initial hemorrhage) and the levels of serum biomarkers were detected. Baseline information, complications, and outcomes at 6 months were recorded. Univariate and multivariate logistic regression analyses were used to explore the relationship between biomarkers and clinical outcomes. Receiver operating characteristic curves were obtained to investigate the possibility of the biomarkers predicting prognosis. Of the 146 patients, 102 patients achieved good outcomes and 44 patients had poor outcomes. Univariate and multivariate analyses showed that high World Federation of Neurosurgical Societies grade, high serum D-dimer levels, and high neurological complications were significantly associated with poor outcomes. Receiver operating characteristic curves verified that D-dimer levels were associated with poor outcomes. D-dimer levels strongly correlated with neurological complications. In conclusion, we suggest that D-dimer levels are a good independent prognostic factor for poor outcomes in patients with aneurysmal subarachnoid hemorrhage.