Role of CT perfusion imaging in the diagnosis and treatment of vasospasm

Outcomes Measures in Subarachnoid Hemorrhage Research

Despite advancements in acute management, morbidity rates for subarachnoid hemorrhage (SAH) remain high. Therefore, it is imperative to utilize standardized outcome scales in SAH research for evaluating new therapies effectively. This review offers a comprehensive overview of prevalent scales and clinical outcomes used in SAH assessment, accompanied by recommendations for their application and prognostic accuracy. Standardized terminology and diagnostic criteria should be employed when reporting pathophysiological outcomes such as symptomatic vasospasm and delayed cerebral ischemia. Furthermore, integrating clinical severity scales like the World Federation of Neurosurgical Societies scale and modified Fisher score into clinical trials is advised to evaluate their prognostic significance, despite their limited correlation with outcomes. The modified Rankin score is widely used for assessing functional outcomes, while the Glasgow outcome scale-extended version is suitable for broader social and behavioral evaluations. Avoiding score dichotomization is crucial to retain valuable information. Cognitive and behavioral outcomes, though frequently affected in patients with favorable neurological outcomes, are often overlooked during follow-up outpatient visits, despite their significant impact on quality of life. Comprehensive neuropsychological evaluations conducted by trained professionals are recommended for characterizing cognitive function, with the Montreal Cognitive Assessment serving as a viable screening tool. Additionally, integrating psychological inventories like the Beck Depression and Anxiety Inventory, along with quality-of-life scales such as the Stroke-Specific Quality of Life Scale, can effectively assess behavioral and quality of life outcomes in SAH studies.

Transcranial Doppler in the Detection of Cerebral Vasospasm After Subarachnoid Hemorrhage

Background Transcranial Doppler (TCD) is a simple, noninvasive, nonionizing, portable technique but not widely practiced to detect cerebral vasospasm after subarachnoid hemorrhage (SAH). Objective The aim of this study was to assess the performance of TCD in the detection of cerebral vasospasm in patients with SAH considering CT angiography (CTA) as a gold standard. Methods and material This cross-sectional study included 50 patients with acute SAH admitted to the National Institute of Neurosciences & Hospital (NINS & H), Dhaka, Bangladesh, from February to June 2021. The neurological status, severity of SAH, and initial CT findings were recorded. All patients were screened for cerebral vasospasm with TCD on the 4th, 7th, 10th, and 14th days after the event. Screening of cerebral vasospasm by CTA was done on the 14th day of the event or earlier if TCD suggested vasospasm. Results The mean age of the participants was 51.4 ±13.4 years (mean ± SD), and females were predominant (N=29, 58%). CTA detected cerebral vasospasm in 18 (36%) participants, but TCD could detect it in only 13 (26%) cases. Among the participants who had no vasospasm by CTA, all but one were also found to have no vasospasm by TCD. The agreement between TCD and CTA in detecting cerebral vasospasm was significant (p<0.001, κ=0.726). TCD shows good specificity (96.9%) and positive predictive value (92.8%), but sensitivity (72.2%) and negative predictive value (81.6%) were comparatively lower. Overall, the diagnostic accuracy of TCD in detecting cerebral vasospasm was 88%. Conclusions Although compared to CTA, TCD is a highly specific but less sensitive tool in detecting vasospasm, TCD remains a reliable screening tool for detecting vasospasm following SAH.

Advances in biomarkers for vasospasm - Towards a future blood-based diagnostic test

Objective

Cerebral vasospasm and the resultant delayed cerebral infarction is a significant source of mortality following aneurysmal SAH. Vasospasm is currently detected using invasive or expensive imaging at regular intervals in patients following SAH, thus posing a risk of complications following the procedure and financial burden on these patients. Currently, there is no blood-based test to detect vasospasm.

Methods

PubMed, Web of Science, and Embase databases were systematically searched to retrieve studies related to cerebral vasospasm, aneurysm rupture, and biomarkers. The study search dated from 1997 to 2022. Data from eligible studies was extracted and then summarized.

Results

Out of the 632 citations screened, only 217 abstracts were selected for further review. Out of those, only 59 full text articles met eligibility and another 13 were excluded.

Conclusions

We summarize the current literature on the mechanism of cerebral vasospasm and delayed cerebral ischemia, specifically studies relating to inflammation, and provide a rationale and commentary on a hypothetical future bloodbased test to detect vasospasm. Efforts should be focused on clinical-translational approaches to create such a test to improve treatment timing and prediction of vasospasm to reduce the incidence of delayed cerebral infarction.

CTA Supplemented by CTP Increases Interrater Reliability and Endovascular Treatment Use in Patients with Aneurysmal SAH

BACKGROUND AND PURPOSE

Cerebral vasospasm is a common complication of aneurysmal SAH and remains a risk factor for delayed cerebral ischemia and poor outcome. The interrater reliability of CTA in combination with CTP has not been sufficiently studied. We aimed to investigate the reliability of CTA alone and in combination with CTP in the detection of cerebral vasospasm and the decision to initiate endovascular treatment.

MATERIALS AND METHODS

This is a retrospective single-center study including patients treated for aneurysmal SAH. Inclusion criteria were a baseline CTA and follow-up imaging including CTP due to suspected vasospasm. Three neuroradiologists were asked to grade 15 intracranial arterial segments in 71 cases using a tripartite scale (no, mild <50%, or severe >50% vasospasm). Raters further evaluated whether endovascular treatment should be indicated. The ratings were performed in 2 stages with a minimum interval of 6 weeks. The first rating included only CTA images, whereas the second rating additionally encompassed CTP images. All raters were blinded to any clinical information of the patients.

RESULTS

Interrater reliability for per-segment analysis of vessels was highly variable (κ = 0.16-0.61). We observed a tendency toward higher interrater reliability in proximal vessel segments, except for the ICA. CTP did not improve the reliability for the per-segment analysis. When focusing on senior raters, the addition of CTP images resulted in higher interrater reliability for severe vasospasm (κ = 0.28; 95% CI, 0.10-0.46 versus κ = 0.46; 95% CI, 0.26-0.66) and subsequently higher concordance (κ = 0.23; 95% CI, -0.01-0.46 versus κ = 0.73; 95% CI, 0.55-0.91) for the decision of whether endovascular treatment was indicated.

CONCLUSIONS

CTA alone offers only low interrater reliability in the graduation of cerebral vasospasm. However, using CTA in combination with CTP might help, especially senior neuroradiologists, to increase the interrater reliability to identify severe vasospasm following aneurysmal SAH and to increase the reliability regarding endovascular treatment decisions.

The impact of perfusion computed tomography on the diagnosis and outcome of delayed cerebral ischemia after subarachnoid hemorrhage

BACKGROUND

Delayed cerebral ischemia (DCI) is a preventable cause of poor neurological outcome in aneurysmal subarachnoid hemorrhage (aSAH). Advances in radiological methods, such as cerebral perfusion computed tomography (CTP), could help diagnose DCI earlier and potentially improve outcomes in aSAH. The objective of this study was to assess whether the use of CTP to diagnose DCI early could reduce the risk of infarction related to DCI.

METHODS

Retrospective cohort study of patients in the intensive care unit of Erasme Hospital (Brussels, Belgium) between 2004 and 2021 with aSAH who developed DCI. Patients were classified as: "group 1" - DCI diagnosed based on clinical deterioration or "group 2" - DCI diagnosed using CTP. The primary outcome was the development of infarction unrelated to the initial bleeding or surgery.

RESULTS

211 aSAH patients were diagnosed with DCI during the study period: 139 (66%) in group 1 and 72 (34%) in group 2. In group 1, 109 (78%) patients developed a cerebral infarction, compared to 45 (63%) in group 2 (p = 0.02). The adjusted cumulative incidence of DCI over time was lower in group 2 than in group 1 [hazard ratio 0.65 (95% CI 0.48-0.94); p = 0.02]. The use of CTP to diagnose DCI was not independently associated with mortality or neurological outcome.

CONCLUSIONS

The use of CTP to diagnose DCI might help reduce the risk of developing cerebral infarction after aSAH, although the impact of such an approach on patient outcomes needs to be further demonstrated.

Twelve controversial questions in aneurysmal subarachnoid hemorrhage

Critical care management of aneurysmal subarachnoid hemorrhage (aSAH) remains a major challenge. Despite the recent publication of guidelines from the American Heart Association/American Stroke Association and the Neurocritical Care Society, there are many controversial questions in the intensive care unit (ICU) management of this population. The authors provide an analysis of common issues in the ICU and provide guidance on the daily management of this specific population of neurocritical care patients.

Intracranial dynamics biomarkers at traumatic cerebral vasospasm

Introduction

Patients who suffer severe traumatic brain injury (sTBI) and cerebral vasospasm (CVS) frequently have posttraumatic cerebral ischemia (PCI).

The research question

was to study changes in cerebral microcirculatory bed parameters in sTBI patients with CVS and with or without PCI.

Material and methods

A total of 136 severe TBI patients were recruited in the study. All patients underwent perfusion computed tomography, intracranial pressure monitoring, and transcranial Doppler. The levels of cerebrovascular resistance (CVR), cerebral arterial compliance (CAC), cerebrovascular time constant (CTC), and critical closing pressure (CCP) were measured using the neuromonitoring complex. Statistical analysis was performed using parametric and nonparametric methods and factor analysis. The patients were dichotomized into PCI-positive (n = 114) and PCI-negative (n = 22) groups. Data are presented as mean values (standard deviations).

Results

CVR was significantly increased, whereas CAC, CTC, and CCP were significantly decreased in sTBI patients with CVS and PCI development (p < 0.05). Factor analyses revealed that all studied microcirculatory bed parameters were significantly associated with the development of PCI (p < 0.05).

Discussion and conclusion

The changes in all studied microcirculatory bed parameters in TBI patients with CVS were significantly associated with PCI development, which enables us to regard them as the biomarkers of CVS and PCI development. The causes of the described microcirculatory bed parameters changes might include complex (cytotoxic and vasogenic) brain edema development, regional microvascular spasm, and dysfunction of pericytes. A further prospective study is warranted.

Post-traumatic hydrocephalus: An overview of classification, diagnosis, treatment, and post-treatment imaging evaluation

The syndrome of post-traumatic hydrocephalus (PTH) has been recognized since Dandy's report in 1914. The pathogenesis of PTH has not been fully clarified. At present, it is believed that the obstacles of cerebrospinal fluid (CSF) secretion, absorption and circulation pathways are the reasons for the development of PTH. However, recent studies have also suggested that the osmotic pressure load of CSF and the pathological changes of CSF dynamics are caused by the development of hydrocephalus. Therefore, a better understanding of the definition, classification, diagnostic criteria, treatment, and evaluation of post-treatment effects of PTH is critical for the effective prevention and treatment of PTH. In this paper, we reviewed the classification and diagnosis of PTH and focused on the treatment and the imaging evaluation of post-treatment effects of PTH. This review might provide a judgment criterion for diagnosis of PTH and a basis for the effective prevention and treatment of PTH in the future.

Release of Hyaluronan in Aneurysmal Subarachnoid Hemorrhage and Cerebral Vasospasm: A Pilot Study Indicating a Shedding of the Endothelial Glycocalyx

BACKGROUND

This pilot study investigated plasma concentrations of hyaluronan, heparan sulfate, and syndecan-1 as possible biomarkers for glycocalyx integrity after aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

Daily blood samples for biomarker assay were obtained in aSAH patients on the intensive care unit stay and compared with samples from a historic cohort of 40 healthy controls. In post hoc subgroup analyses in patients with and without cerebral vasospasm, we explored the influence of aSAH-related cerebral vasospasm on biomarker levels.

RESULTS

A total of 18 aSAH patients and 40 historic controls were included in the study. Median (interquartile range) plasma levels of hyaluronan were higher in aSAH patients compared with controls (131 [84 to 179] vs. 92 [82 to 98] ng/mL, respectively; P=0.009), whereas heparan sulfate (mean±SD: 754±428 vs. 1329±316 ng/mL; P<0.001) and syndecan-1 (median: 23 [17 to 36] vs. 30 [23 to 52] ng/mL; P=0.02) levels were lower. Patients who developed vasospasm had significantly higher median hyaluronan concentrations at day 7 (206 [165 to 288] vs. 133 [108 to 164] ng/mL, respectively; P=0.009) and at day of first vasospasm detection (203 [155 to 231] vs. 133 [108 to 164] ng/mL, respectively; P=0.01) compared with those without vasospasm. Heparan sulfate and syndecan-1 concentrations were similar in patients with and without vasospasm.

CONCLUSIONS

The increased plasma concentrations of hyaluronan after aSAH suggest selective shedding of this component of the glycocalyx. Increased levels of hyaluronan in patients with cerebral vasospasm, underlines a potential role for hyaluronan in vasospasm processes.

Pathophysiology of Early Brain Injury and Its Association with Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage: A Review of Current Literature

Background: Delayed cerebral ischemia (DCI) is a common and serious complication of aneurysmal subarachnoid hemorrhage (aSAH). Though many clinical trials have looked at therapies for DCI and vasospasm in aSAH, along with reducing rebleeding risks, none have led to improving outcomes in this patient population. We present an up-to-date review of the pathophysiology of DCI and its association with early brain injury (EBI). Recent Findings: Recent studies have demonstrated that EBI, as opposed to delayed brain injury, is the main contributor to downstream pathophysiological mechanisms that play a role in the development of DCI. New predictive models, including advanced monitoring and neuroimaging techniques, can help detect EBI and improve the clinical management of aSAH patients. Summary: EBI, the severity of subarachnoid hemorrhage, and physiological/imaging markers can serve as indicators for potential early therapeutics in aSAH. The microcellular milieu and hemodynamic pathomechanisms should remain a focus of researchers and clinicians. With the advancement in understanding the pathophysiology of DCI, we are hopeful that we will make strides toward better outcomes for this unique patient population.

Computation of contrast-enhanced perfusion using only two CT scan phases: a proof-of-concept study on abdominal organs

Background

Computed tomography perfusion imaging (CTPI) by repeated scanning has clinical relevance but implies relatively high radiation exposure. We present a method to measure perfusion from two CT scan phases only, considering tissue enhancement, feeding vessel (aortic) peak enhancement, and bolus shape.

Methods

CTPI scans (each with 40 frames acquired every 1.5 s) of 11 patients with advanced hepatocellular carcinoma (HCC) enrolled between 2012 and 2016 were retrospectively analysed (aged 69 ± 9 years, 8/11 males). Perfusion was defined as the maximal slope of the time-enhancement curve divided by the peak enhancement of the feeding vessel (aorta). Perfusion was computed two times, first using the maximum slope derived from all data points and then using the peak tissue enhancement and the bolus shape obtained from the aortic curve.

Results

Perfusion values from the two methods were linearly related (r2 = 0.92, p < 0.001; Bland–Altman analysis bias -0.12). The mathematical model showed that the perfusion ratio of two ROIs with the same feeding vessel (aorta) corresponds to their peak enhancement ratio (r2 = 0.55, p < 0.001; Bland–Altman analysis bias -0.68). The relationship between perfusion and tissue enhancement is predicted to be linear in the clinical range of interest, being only function of perfusion, peak feeding vessel enhancement, and bolus shape.

Conclusions

This proof-of-concept study showed that perfusion values of HCC, kidney, and pancreas could be computed using enhancement measured only with two CT scan phases, if aortic peak enhancement and bolus shape are known.

Feasibility of FDCT Early Brain Parenchymal Blood Volume Maps in Predicting Short-Term Prognosis in Patients With Aneurysmal Subarachnoid Hemorrhage

Purpose

Aneurysmal subarachnoid hemorrhage (SAH) is accompanied by cerebral perfusion changes. We aimed to measure the parenchymal blood volume (PBV) maps acquired by C-arm flat-panel detector CT (FDCT) to assess the cerebral blood volume at an early stage in aneurysmal SAH and to explore the correlation with the outcomes at discharge.

Methods

Data of 66 patients with aneurysmal SAH who underwent FDCT PBV examination were retrospectively analyzed. The PBV of regions of interest, including the cortices of the bilateral frontal lobe, the parietal lobe, the occipital lobe, and the cerebral hemisphere, as well as the basal ganglia, were measured and quantitatively analyzed. The clinical and imaging data of the patients were also collected, and logistic regression analysis was performed to explore the correlation between the perfusion parameters and outcomes at discharge.

Results

The favorable and poor outcomes at discharge were found in 37 (56.06%) and 29 (43.94%) patients, respectively. The whole-brain PBV was significantly correlated with the Hunt-Hess grades (p < 0.005) and the WFNSS grades (p < 0.005). The whole-brain PBV of the poor prognosis was significantly higher than that of the favorable prognosis (35.17 ± 7.66 vs. 29.78 ± 5.54, p < 0.005). The logistic regression analysis showed that the PBV of the parietal lobe at the bleeding side (OR = 1.10, 95%CI: 1.00-1.20, p = 0.04) was an independent risk factor predicting the short-term prognosis.

Conclusions

Parenchymal blood volume (PBV) maps could reflect the cerebral blood volume throughout the brain to characterize its perfusion status at an early stage in aneurysmal SAH. It enables a one-stop imaging evaluation and treatment in the same angio-suite and may serve as a reliable technique in clinical assessment of aneurysmal SAH.

Cerebrospinal Fluid and Arterial Acid-Base Equilibrium of Spontaneously Breathing Patients with Aneurismal Subarachnoid Hemorrhage

BACKGROUND

Hyperventilation resulting in hypocapnic alkalosis (HA) is frequently encountered in spontaneously breathing patients with acute cerebrovascular conditions. The underlying mechanisms of this respiratory response have not been fully elucidated. The present study describes, applying the physical-chemical approach, the acid-base characteristics of cerebrospinal fluid (CSF) and arterial plasma of spontaneously breathing patients with aneurismal subarachnoid hemorrhage (SAH) and compares these results with those of control patients. Moreover, it investigates the pathophysiologic mechanisms leading to HA in SAH.

METHODS

Patients with SAH admitted to the neurological intensive care unit and patients (American Society of Anesthesiologists physical status of 1 and 2) undergoing elective surgery under spinal anesthesia were enrolled. CSF and arterial samples were collected simultaneously. Electrolytes, strong ion difference (SID), partial pressure of carbon dioxide (PCO₂), weak noncarbonic acids (A_TOT), and pH were measured in CSF and arterial blood samples.

RESULTS

Twenty spontaneously breathing patients with SAH and 25 controls were enrolled. The CSF of patients with SAH, as compared with controls, was characterized by a lower SID (23.1 ± 2.3 vs. 26.5 ± 1.4 mmol/L, p < 0.001) and PCO₂ (40 ± 4 vs. 46 ± 3 mm Hg, p < 0.001), whereas no differences in A_TOT (1.2 ± 0.5 vs. 1.2 ± 0.2 mmol/L, p = 0.95) and pH (7.34 ± 0.06 vs. 7.35 ± 0.02, p = 0.69) were observed. The reduced CSF SID was mainly caused by a higher lactate concentration (3.3 ± 1.3 vs. 1.4 ± 0.2 mmol/L, p < 0.001). A linear association (r = 0.71, p < 0.001) was found between CSF SID and arterial PCO₂. A higher proportion of patients with SAH were characterized by arterial HA, as compared with controls (40 vs. 4%, p = 0.003). A reduced CSF-to-plasma difference in PCO₂ was observed in nonhyperventilating patients with SAH (0.4 ± 3.8 vs. 7.8 ± 3.7 mm Hg, p < 0.001).

CONCLUSIONS

Patients with SAH have a reduction of CSF SID due to an increased lactate concentration. The resulting localized acidifying effect is compensated by CSF hypocapnia, yielding normal CSF pH values and resulting in a higher incidence of arterial HA.

Delayed Cerebral Ischemia after Subarachnoid Hemorrhage

Delayed cerebral ischemia (DCI) is the most feared complication of aneurysmal subarachnoid hemorrhage (aSAH). It increases the mortality and morbidity associated with aSAH. Previously, large cerebral artery vasospasm was thought to be the sole major contributing factor associated with increased risk of DCI. Recent literature has challenged this concept. We conducted a literature search using PUBMED as the prime source of articles discussing various other factors which may contribute to the development of DCI both in the presence or absence of large cerebral artery vasospasm. These factors include microvascular spasm, micro-thrombosis, cerebrovascular dysregulation, and cortical spreading depolarization. These factors collectively result in inflammation of brain parenchyma, which is thought to precipitate early brain injury and DCI. We conclude that diagnostic modalities need to be refined in order to diagnose DCI more efficiently in its early phase, and newer interventions need to be developed to prevent and treat this condition. These newer interventions are currently being studied in experimental models. However, their effectiveness on patients with aSAH is yet to be determined.

Four-dimensional computed tomography angiography analysis of internal carotid arteries opacification at the skull base to detect delayed cerebral ischemia: a feasibility study

PURPOSE

Delayed cerebral ischemia represents a significant cause of poor functional outcome for patients with vasospasm after subarachnoid hemorrhage. We investigated whether delayed cerebral ischemia could be detected by the arterial opacification of internal carotid artery at the level of the skull base.

METHODS

In this exploratory, nested retrospective cohort diagnostic accuracy study, patients with clinical and/or transcranial Doppler suspicion of vasospasm who underwent four-dimensional computed tomography angiography were included. They were split into two groups for the main endpoint analysis, according to the actually adopted morphological (cerebral infarction) and clinical criteria (neurologic deterioration) of delayed cerebral ischemia. Opacification with a temporal resolution of 0.15 s of both internal carotid arteries at the skull base level was obtained through a semi-automated segmentation method based on skeletonization, and analyzed by a wavelet transform (rbio2.2, level 1). The results obtained by k-means clustering were analyzed with regard to the state of delayed cerebral infarction.

RESULTS

Over ten patients included and analyzed, five patients presented a delayed cerebral ischemia, two of them in both side. The semi-automated processing and analysis clustered two different types of opacification curves. The obtaining of a nonlinear opacification pattern was associated (p < 0.001) with delayed cerebral ischemia.

CONCLUSIONS

The analysis of arterial opacification of internal carotid arteries at skull base by the proposed processing is feasible and leads to cluster two types of opacification that may help to early detect and prevent delayed cerebral ischemia, in particularly when examinations are artifacted by aneurysm treatment materials.

[Significance of CT perfusion examination of cerebral blood flow for assessing the risk of brain ischemia in patients with intracranial arterial aneurysm ruptures]

Prognosing the outcome of cerebral ischemia in the acute SAH phase still remains the topical issue for clinical practice because this largely affects the choice of an optimal timing of aneurysm clipping. The traditional criteria are often not effective enough to predict changes in cerebral ischemia, especially in patients in a compensated or subcompensated state who often develop delayed ischemia, which may lead to serious complications. The introduction of a CT perfusion technique for evaluating the volumetric cerebral blood flow stimulated the development of a new stage in investigation of cerebral ischemia in non-traumatic SAH.

PURPOSE

The study purpose was to evaluate the significance of cerebral blood flow indicators obtained by CT perfusion for prediction of delayed cerebral ischemia and postoperative ischemic complications to optimize treatment of patients with ruptures of intracranial arterial aneurysms.

MATERIAL AND METHODS

The study included 70 patients who underwent aneurysm clipping and 42 non-operated patients. The inclusion criteria were as follows: WFNS grade I-III condition, vasospasm according to transcranial Doppler sonography, and availability of CT scans, including CT perfusion data. The vasospasm severity and perfusion indicators _(rCBV and MTT) were evaluated. The severity of subarachnoid and ventricular hemorrhage was evaluated according to the A. Hijdra method. The final results were evaluated using a clinical-statistical method, including ROC analysis.

RESULTS

An analysis of the obtained data revealed that the risk of delayed cerebral ischemia and postoperative ischemia increases significantly if the baseline hemispheric CBF value is below a threshold of 40 ml/100 g/min, and the baseline MMT indicator is above a threshold of 5 s. There was asymmetry of these CT perfusion indicators due to a larger deviation from the threshold values in the homolateral hemisphere compared to the opposite side. The ROC analysis results demonstrated diagnostic sensitivity and diagnostic specificity of the CT perfusion technique.

CONCLUSION

The CT perfusion data together with the SAH severity and localization indicators may be used as predictors for the cerebral ischemia outcome in choosing the optimal timing of aneurysm clipping during the acute SAH period in patients in a WFNS grade I-III condition and with signs of mild or moderate vasospasm.

Transcranial Doppler Versus CT-Angiography for Detection of Cerebral Vasospasm in Relation to Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage: A Prospective Single-Center Cohort Study: The Transcranial doppler and CT-angiography for Investigating Cerebral vasospasm in Subarachnoid hemorrhage (TACTICS) study

Cerebral vasospasm in the first 2 weeks after aneurysmal subarachnoid hemorrhage is recognized as a major predictor of delayed cerebral ischemia. The routine screening for cerebral vasospasm with either transcranial Doppler or CT angiography has been advocated, although its diagnostic value has not yet been determined. Our study investigated the diagnostic accuracy of detecting vasospasm by transcranial Doppler and CT angiography for the prediction of delayed cerebral ischemia and functional outcome. Additionally, agreement between transcranial Doppler and CT angiography was determined.

Design

Prospective diagnostic accuracy study.

Settings

Neurocritical care unit and neurosurgical ward at a tertiary academic medical center.

Patients

Between 2013 and 2016, 59 consenting patients were included.

Intervention

Patients undergo both transcranial Doppler and CT angiography for detection of cerebral vasospasm on days 5 and 10 after aneurysmal subarachnoid hemorrhage. Delayed cerebral ischemia was defined as secondary neurologic deterioration, not explained otherwise. Unfavorable outcome was defined modified Rankin Scale > 2 at 6 months.

Measurements and Main Results

On transcranial Doppler, cerebral vasospasm was observed in 26 patients (45%). On CT angiography, vasospasm was observed in 54 patients (95%). The agreement between transcranial Doppler and CT angiography was 0.47. Delayed cerebral ischemia occurred in 16 patients (27%); unfavorable outcome in 12 patients (20%). Transcranial Doppler predicted delayed cerebral ischemia with a sensitivity of 0.44 (day 5) and 0.50 (day 10), with a specificity of 0.67 (day 5) and 0.57 (day 10). CT angiography predicted delayed cerebral ischemia with a sensitivity of 0.81 (day 5 and 10) and with a specificity of 0.070 (day 5) and 0.00 (day 10). The highest accuracy for predicting unfavorable outcome was on day 5 (0.61 for transcranial Doppler vs 0.27 for CT angiography).

Conclusion

The diagnostic accuracy of both CT angiography and transcranial Doppler for detection of cerebral vasospasm as well as prediction of delayed cerebral ischemia and functional outcome is limited. The agreement between CT angiography and transcranial Doppler is low.

The impact of temporary clipping during aneurysm surgery on the incidence of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

OBJECTIVE Clipping of a ruptured intracranial aneurysm requires some degree of vessel manipulation, which in turn is believed to contribute to vasoconstriction. One of the techniques used during surgery is temporary clipping of the parent vessel. Temporary clipping may either be mandatory in cases of premature rupture (rescue) or represent a precautionary or facilitating surgical step (elective). The aim of this study was to study the association between temporary clipping during aneurysm surgery and the incidence of vasospasm and delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage (aSAH) in a large clinical series. METHODS Seven hundred seventy-eight patients who underwent surgical aneurysm treatment after aSAH were retrospectively included in the study. In addition to surgical parameters, the authors recorded transcranial Doppler (TCD) sonography-documented vasospasm (TCD-vasospasm, blood flow acceleration > 120 cm/sec), delayed ischemic neurological deficits (DINDs), and delayed cerebral infarction (DCI). Multivariate binary logistic regression analysis was applied to assess the association between temporary clipping, vasospasm, DIND, and DCI. RESULTS Temporary clipping was performed in 338 (43.4%) of 778 patients during aneurysm surgery. TCD sonographic flow acceleration developed in 370 (47.6%), DINDs in 123 (15.8%), and DCI in 97 (12.5%). Patients with temporary clipping showed no significant increase in the incidence of TCD-vasospasm compared with patients without temporary clipping (49% vs 48%, respectively; p = 0.60). DINDs developed in 12% of patients with temporary clipping and 18% of those without temporary clipping (p = 0.01). DCI occurred in 9% of patients with temporary clipping and 15% of those without temporary clipping (p = 0.02). The need for rescue temporary clipping was a predictor for DCI; 19.5% of patients in the rescue temporary clipping group but only 11.3% in the elective temporary clipping group had infarcts (p = 0.02). Elective temporary clipping was not associated with TCD-vasospasm (p = 0.31), DIND (p = 0.18), or DCI (p = 0.06). CONCLUSIONS Temporary clipping did not contribute to a higher rate of TCD-vasospasm, DIND, or DCI in comparison with rates in patients without temporary clipping. In contrast, there was an association between temporary clipping and a lower incidence of DINDs and DCI. There is no reason to be hesitant in using elective temporary clipping if deemed appropriate.

Early Hemodynamic Changes Based on Initial Color-Coding Angiography as a Predictor for Developing Subsequent Symptomatic Vasospasm After Aneurysmal Subarachnoid Hemorrhage

INTRODUCTION

Prediction of vasospasm after aneurysmal subarachnoid hemorrhage (aSAH) remains imperfect and currently relies on clinical and radiographic characteristics. Whether early hemodynamic changes may refine risk stratification for delayed vasospasm (DV) after aSAH was analyzed.

METHODS

Patients with aSAH (n = 53) and a control group with unruptured intracranial aneurysms (UIA) (n = 12) with initial color-coding angiography at admission were included in this study (n = 65). Clinical and radiologic data were collected, and uni- and multivariate analysis was used to correlate the occurrence of DV (manifesting clinically or detected with transcranial Doppler or angiography) with hemodynamic features of the initial angiography including Tmax and mean transit times (MTTs).

RESULTS

In the aSAH patient cohort, 37 of 53 patients with aSAH (70%) developed DV. After we controlled for the effects of age, Hunt and Hess grade, and modified Fisher grade, patients with DV had a shorter mean region of interest peak time (Tmax) of the anterior cerebral artery A2 segment (P = 0.036) and the middle cerebral artery M1 (P = 0.045) and M3 (P = 0.013) segments. Mean MTTs between internal carotid artery to middle cerebral artery M3 segment (P = 0.026) was also significantly shorter in patients with DV when compared with controls.

CONCLUSIONS

Tmax and MTT on angiography within 48 hours of aneurysm rupture before treatment provide an early quantitative assessment in patients with aSAH and in this small study were predictive for the development of subsequent symptomatic DV. Early identification of patients with aSAH at greatest risk of DV may ameliorate clinical outcome through timely, selective implementation of aggressive prophylactic therapy to prevent the effects of DV.

Early whole-brain CT perfusion for detection of patients at risk for delayed cerebral ischemia after subarachnoid hemorrhage

OBJECT This prospective study investigated the role of whole-brain CT perfusion (CTP) studies in the identification of patients at risk for delayed ischemic neurological deficits (DIND) and of tissue at risk for delayed cerebral infarction (DCI). METHODS Forty-three patients with aneurysmal subarachnoid hemorrhage (aSAH) were included in this study. A CTP study was routinely performed in the early phase (Day 3). The CTP study was repeated in cases of transcranial Doppler sonography (TCD)-measured blood flow velocity (BFV) increase of > 50 cm/sec within 24 hours and/or on Day 7 in patients who were intubated/sedated. RESULTS Early CTP studies revealed perfusion deficits in 14 patients, of whom 10 patients (72%) developed DIND, and 6 of these 10 patients (60%) had DCI. Three of the 14 patients (21%) with early perfusion deficits developed DCI without having had DIND, and the remaining patient (7%) had neither DIND nor DCI. There was a statistically significant correlation between early perfusion deficits and occurrence of DIND and DCI (p < 0.0001). A repeated CTP was performed in 8 patients with a TCD-measured BFV increase > 50 cm/sec within 24 hours, revealing a perfusion deficit in 3 of them (38%). Two of the 3 patients (67%) developed DCI without preceding DIND and 1 patient (33%) had DIND without DCI. In 4 of the 7 patients (57%) who were sedated and/or comatose, additional CTP studies on Day 7 showed perfusion deficits. All 4 patients developed DCI. CONCLUSIONS Whole-brain CTP on Day 3 after aSAH allows early and reliable identification of patients at risk for DIND and tissue at risk for DCI. Additional CTP investigations, guided by TCD-measured BFV increase or persisting coma, do not contribute to information gain.

Imaging and decision-making in neurocritical care

Critically ill neurologic patients are common in the hospital practice of neurology and are often in extreme states requiring accurate and specific information. Imaging, especially using advanced imaging techniques, can provide an important means of garnering this information. This article focuses on the clinical utilization of selective imaging methods that are commonly used in critically ill neurologic patients to render diagnoses, to monitor effects of treatment, or have contributed to a better understanding of pathophysiology in the intensive care unit.