Hyperdense middle cerebral artery sign predicts favorable outcome in patients undergoing mechanical thrombectomy.

Non-contrast computer tomography detects the presence of hyperdense middle cerebral artery sign (HMCAS). Studies on the prognostic value of HMCAS among patients undergoing mechanical thrombectomy (MT) are conflicting. A retrospective analysis of consecutive patients with acute ischemic stroke due to middle cerebral artery occlusion, presenting with or without HMCAS, who underwent MT, was performed. We enrolled 191 patients (HMCAS +, n = 140; HMCAS -, n = 51). Prevalence of successful recanalization was significantly higher in patients with HMCAS than in those without HMCAS (92.1% versus 74.5%, p = 0.001). Patients with HMCAS had a better clinical outcome than those HMCAS - (54.3% versus 37.3%, p = 0.037, for three-month favorable outcome; 62.9% versus 39.3%, p = 0.004, for major neurological improvement at discharge; 8.6% versus 19.6%, p = 0.035, for in-hospital mortality; 14.3% versus 27.5%, p = 0.035, for intracranial hemorrhage; 2.9% versus 17.6%, p = 0.001, for symptomatic intracranial hemorrhage). Multivariate analyses confirmed that HMCAS represents an independent predictor of three-month favorable outcome (OR 2.48, 95% CI 1.10-5.58, p = 0.028), major neurological improvement at discharge (OR 2.40, 95% CI 1.09-5.20, p = 0.030), in-hospital mortality (OR 0.29, 95% CI 0.010-0.81, p = 0.018), presence of ICH (OR 0.49, 95% CI 0.25-0.97, p = 0.042) and presence of SICH (OR 0.16, 95% CI 0.04-0.63, p = 0.009). HMCAS presence predicts favorable outcome in patients undergoing MT. This result may indicate that hyperdense clots are more likely to respond to MT than isodense ones. This effect is mediated by reduction in hemorrhagic transformation.

The Hyperdense middle cerebral artery sign is associated with poor leptomeningeal collaterals in acute ischemic stroke: a retrospective study.

BACKGROUND: The hyperdense middle cerebral artery sign (HMCAS) is an early radiological marker to provide an early diagnosis and to identify ischemia. As reported, HMCAS is associated with heavy clot burden. Moreover, a heavy clot burden may cause obstruction of the orifices of arteries for leptomeningeal collateral flows and can lead to severe clinical conditions. However, the direct relationship between HMCAS and collateral flows remains unclear. Therefore, we explored the association between HMCAS and leptomeningeal collaterals in patients with acute ischemic stroke. METHODS: Consecutive ischemic stroke patients were enrolled from January 2015 to April 2021. HMCAS appearance and collateral status were detected by multimodal computed tomography at admission. Logistic regression analyses helped to identify the association between HMCAS, collateral flows and stroke severity. RESULTS: In 494 included patients, 180 (36.4%) presented with HMCAS. Ipsilateral collaterals were not seen or less prominent in patients with HMCAS (P < 0.001). The HMCAS appearance was significantly associated with less collaterals (odds ratio 5.17, 95% confidence interval 3.27-8.18, P < 0.001), internal carotid artery + M1/M1 occlusion, the initial stroke severity and follow-up outcomes. Subgroup analyses further confirmed HMCAS as an indicator of poor collaterals in ischemic stroke (all P values < 0.05). CONCLUSIONS: HMCAS is associated with poor leptomeningeal collaterals, the stroke severity and a poor neurological outcome. Therefore, the HMCAS appearance can act as an early warning sign for healthcare professionals to be alert for poor collateral flows and poor neurological outcomes in ischemic stroke patients with middle cerebral artery occlusion.

Hyperdense middle cerebral artery sign predicts favorable outcome after decompressive craniectomy in patients with malignant middle cerebral artery infarction.

BACKGROUND: Malignant middle cerebral artery infarction (MMI) is a life-threatening cerebral vascular event. Early decompressive craniectomy (DC) has proven to be an effective treatment strategy. However, the ideal candidate for DC continues to be debated. PURPOSE: To investigate whether a hyperdense middle cerebral artery sign (HMCAS) provides prognostic value after DC in patients with MMI. MATERIAL AND METHODS: We reviewed clinical information and radiological parameters on computed tomography of 42 patients with MMI who underwent DC. Functional outcome was assessed according to the modified Rankin scale (mRS) at three months as follows: favorable outcome (mRS ≤ 4) versus unfavorable outcome (mRS > 4). Logistic regression analysis was used to identify predictors of functional outcome after DC in patients with MMI. RESULTS: Age (odds ratio [OR] = 0.87; 95% confidence interval [CI] = 0.78-0.97; P = 0.014) and HMCAS (OR = 7.40; 95% CI = 1.35-40.48; P = 0.021) were associated with functional outcome. The area under the receiver operating characteristic curve for predicting favorable outcome using the combination of age and HMCAS was 0.882, and the sensitivity and specificity were 0.947 and 0.696, respectively. CONCLUSION: Patients with MMI with HMCAS, as well as younger patients, often showed a favorable outcome after DC in this study.

Is it possible to predict the outcome of endovascular thrombectomy for hyperdense middle cerebral artery sign at the time of first admission?

Background: The hyperdense middle cerebral artery sign (HMCAS) on admission non-contrast computed tomography (NCCT) is a well-characterized phenomenon in acute ischemic stroke. Aim: The purpose of this study is to determine the impact of HMCAS on the outcome of patients who underwent endovascular thrombectomy. Materials and Methods: A retrospective analysis of a prospectively collective database included 136 consecutive patients with anterior circulation acute ischemic stroke who underwent endovascular thrombectomy. We collected the demographics, and clinical and brain imaging as well as functional and imaging outcomes data at baseline. Patients were divided into two groups with hyperdense artery sign and those without the sign. The difference between the two groups in terms of mortality and prognosis was analyzed. Results: There were 136 patients, 50.7% of them were women. The mean age was 59.1 years. The subgroup with HMCAS present consisted of 93 patients. There were no differences in demographics and clinical characteristics between the two groups; however, tobacco use is more common in patients with HMCAS. No significant difference was observed in clinical outcomes and mortality between the two groups at 3 months. Patients with HMCAS had statistically more new territory emboli during the procedure (9.7%) compared to patients without HMCAS. Conclusion: We showed that the presence of HMCAS in initial CT was not helpful in predicting good clinical outcomes in patients undergoing endovascular therapy patients. However, the presence of HMCAS is related to more new territory embolism during the procedure. Different endovascular strategies may be applied to these patients.

Intravenous thrombolysis for ischemic stroke with hyperdense middle cerebral artery sign: A meta-analysis.

Hyperdense middle cerebral artery sign (HMCAS) on admitting to neuroimaging is reported to have prognostic value for poor outcomes after thrombolysis, while evidence from studies comprising a sufficiently large sample size is limited. To detect prognostic predictors after thrombolysis could help improve therapeutic clinical strategies for acute ischemic stroke. We included prospective and retrospective studies of stroke patients that were treated with intravenous thrombolysis, in which functional outcomes (ie, a modified Rankin scale [mRS]) and systematic intracranial hemorrhage (sICH) were assessed in relation to HMCAS during pretreatment head CT. Random-effects models were used to calculate pooled risk ratios (RR) of poor outcomes and sICH for HMCAS patients as compared to patients without HMCAS. Eleven studies permitted identification of 11 818 patients. The risk of poor outcome at 3 months in the HMCAS-positive group was 1.56-fold the negative group (RR, 1.56; 95% CI 1.50-1.62; P < .001). The sICH risk when comparing both groups was found to be non-significant. Sensitivity analysis regarding studies performing thrombolysis within 3 hours also exhibited significant differences in their functional outcomes (RR, 1.56, 95% CI 1.49-1.62; P < .001) in patients with HMCAS as compared to non-HMCAS patients, although this was true for sICH risk. The presence of HMCAS on pretreatment CT predicts a poor outcome at 3 months after intravenous thrombolysis, while its relationship with the incidence of sICH was found to have no statistic value. Our study implies that more aggressive treatment should be considered for HMCAS patients.

[Efficacy of intravenous thrombolysis in acute ischemic stroke with hyperdense middle cerebral artery sign].

Objective: To observe the efficacy and safety of recombinant tissue-type plasminogen activator (rtPA) intravenous thrombolysis (IVT) in the treatment of acute cerebral infarction with hyperdense middle cerebral artery sign (HMCAS). Methods: Acute cerebral infarction patients with HMCAS from July 2010 to November 2015 at the First Affiliated Hospital of Dalian Medical University were collected.These patients were divided into two groups depending on whether they received IVT or not.The Nation Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) were used to evaluate early and long-time therapeutic effects.Efficacy and safety were compared between the two groups. Results: A total of 93 patients were eligible for the analysis, with 45 cases in IVT group and 48 cases in non-IVT group.As time went by, NIHSS score in IVT group showed significant downward trend than the non-IVT group.The rate of patients with good outcome in IVT group was higher than that in non-IVT group (P<0.05). The rate of hemorrhage transformation (HT) in IVT group and non-IVT group was 35.6% (16/45) and 10.4% (11/48), respectively, and the difference was statistically significant (P<0.05). While no statistically significant difference was found about the rate of symptomatic intracranial hemorrhage (sICH) (8.9% vs 2.1%, P>0.05) and mortality (33.3% vs 27.1%, P>0.05) between these two groups.Logistic regression analysis identified relativity between IVT treatment and good outcome (P<0.05), hemorrhage transformation (P<0.05), rather than mortality (P>0.05). Conclusions: Intravenous thrombolysis with rt-PA is an effective and safe treatment for most acute ischemic stroke patients with HMCAS and can promote early neurologic improvement and significantly improve long-term functional prognosis.Although Ⅳ thrombolysis can increase the risk of overall HT, it does not add risk in sICH and mortality.

How to avoid false positive hyperdense middle cerebral artery sign detection in ischemic stroke.

OBJECTIVES: The aim of the study was to find how to differentiate hyperdense middle cerebral artery sign (HMCAS) in stroke patients from asymmetric hyperdensity not related to stroke, by comparison of the CT density values typical for HMCAS to the values in normal or atherosclerotic middle cerebral artery (MCA). METHODS: The group analyzed consisted of 100 patients with ischemic stroke, presenting HMCAS on the admission CT. Density measurements in HU were performed in the hyperdense segment of the involved MCA, contralateral MCA, brain cortex adjacent to the hyperdense MCA. The control group consisted of 100 patients with no symptoms of cerebral stroke. Density measurements in HU were performed: in the M1 segment of right and left MCA, brain cortex adjacent to the more dense from right or left MCA. RESULTS: In the stroke group the median values obtained were: in the hyperdense MCA 59 HU, contralateral MCA 41 HU, brain cortex 36 HU. In the control group the median values obtained were: in the more dense MCA 43 HU, contralateral MCA 40 HU, brain cortex 34 HU. The range of HMCAS/contralateral MCA density ratios in stroke only slightly overlapped the range of more dense MCA/contralateral MCA density ratios in non-stroke patients. CONCLUSION: The ratio of hyperdense MCA CT density/contralateral density is a good tool to differentiate HMCAS from asymmetric hyperdensity not related to stroke. The threshold ≥1.16 provided 100% sensitivity and 97% specificity, whereas ≥1.22 provided 94% sensitivity and 100% specificity.

Hyperdense middle cerebral artery sign as the only radiological manifestation of hyperacute ischemic stroke in computed tomography.

OBJECTIVES: The main aim of the study was to find the effect of hyperdense middle cerebral artery sign (HMCAS), as the only admission computed tomography (CT) manifestation of ischemic stroke involving middle cerebral artery (MCA) region, on the extent of stroke measured by Alberta Stroke Program Early CT score (ASPECTS) in the follow-up CT. The secondary aim was to determine the correlation between length of hyperdense MCA segment on admission CT and ASPECTS in follow-up CT. METHODS: The group analyzed consisted of 118 patients with ischemic MCA region stroke, with no early signs of brain tissue ischemia on admission CT, but infarcts confirmed in follow-up CT, with extent evaluated using ASPECTS. For the subgroups: 66 patients with HMCAS present and 52 with HMCAS absent, median ASPECTS values were compared. In the subgroup with HMCAS present, length of hyperdense segment was measured and correlation with ASPECTS was determined. RESULTS: The median ASPECTS 6 (min. 0, max. 9) in the subgroup with HMCAS present was significantly lower, compared to the score 8.5 (min. 0, max. 9) in the subgroup with HMCAS absent. Moderate correlation between the length of hyperdense segment and ASPECTS was found (R=-0.45). CONCLUSION: In patients with ischemic stroke involving MCA region and no early signs of brain tissue ischemia on the admission CT, HMCAS is associated with significantly lower ASPECTS in the follow-up CT. There is moderate correlation between the length of hyperdense MCA segment and ASPECTS.

The risk and outcome of malignant brain edema in post-mechanical thrombectomy: acute ischemic stroke by anterior circulation occlusion.

BACKGROUND AND PURPOSE: Malignant brain edema (MBE) occurring after mechanical thrombectomy (MT) in acute ischemic stroke (AIS) could lead to severe disability and mortality. We aimed to investigate the incidence, predictors, and clinical outcomes of MBE in patients with AIS after MT. METHODS: The clinical and imaging data of 155 patients with AIS of anterior circulation after MT were studied. Standard non-contrast CT was used to evaluate baseline imaging characteristics at admission. Clinical outcomes were measured using the 90-day modified Rankin Scale (mRS) score. Based on the follow-up CT scans performed within 72 h after MT, the patients were classified into MBE and non-MBE group. MBE was defined as a midline shift of ≥ 5 mm with signs of local brain swelling. Univariate and multivariate regression analyses were used to analyze the relationship between MBE and clinical outcomes and identify the predictors that correlate with MBE. RESULTS: MBE was observed in 19.4% of the patients who underwent MT and was associated with a lower rate of favorable 90-day clinical outcomes. Significant differences were observed in both MBE and non-MBE groups: baseline Alberta Stroke Program Early CT (ASPECT) score, hyperdense middle cerebral artery sign (HMCAS), baseline signs of early infarct, angiographic favorable collaterals, number of retrieval attempts, and revascularization rate. Multivariate analysis indicated that low baseline ASPECT score, absent HMCAS, angiographic poor collaterals, more retrieval attempt count, and poor revascularization independently influenced the occurrence of MBE in AIS patients with anterior circulation after MT. CONCLUSION: MBE was associated with a lower rate of favorable 90-day clinical outcomes. Low baseline ASPECT score, absent HMCAS, angiographic poor collaterals, more retrieval attempt count and poor revascularization were independently associated with MBE after MT.

Proximal hyperdense middle cerebral artery sign is associated with increased risk of asymptomatic hemorrhagic transformation after endovascular thrombectomy: a multicenter retrospective study.

OBJECTIVE: To investigate whether hyperdense middle cerebral artery sign (HMCAS) on pretreatment no-contrast CT (NCCT) is associated with hemorrhagic transformation (HT) after endovascular thrombectomy (EVT). METHODS: Patients with acute middle cerebral artery (MCA) occlusion who received EVT in three comprehensive hospitals were retrospectively evaluated. They were divided into four groups based on the presence or absence of HMCAS and corresponding CTA findings, among whom differences were compared. Univariate and multivariate logistic regression analyses were performed to investigate the association between HMCAS and HT and its subtypes. RESULTS: 318 patients were included, among whom 149 (46.9%) had HMCAS. Patients in the proximal positive HMCAS group had higher National Institute of Health Stroke Scale scores and lower Alberta Stroke Program Early CT Scores (ASPECTS) than those in the proximal negative HMCAS group. The rate of HT was higher in the proximal positive HMCAS group than that in the proximal negative HMCAS group. In multivariate logistic regression analysis, the proximal HMCAS were independently associated with HT (adjusted OR = 2.073, 95% CI 1.211-3.551, p = 0.008) and aHT (adjusted OR = 2.271, 95% CI 1.294-3.986, p = 0.004), but not with sHT. Patients who developed HT, including aHT and sHT, had a lower rate of good outcome. CONCLUSION: Proximal HMCAS on initial NCCT was independently associated with aHT in patients who received EVT for acute MCA occlusion. Both aHT and sHT had a detrimental effect on clinical outcome.

Usefulness of maximum intensity projection images of non-enhanced CT for detection of hyperdense middle cerebral artery sign in acute thromboembolic ischemic stroke.

PURPOSE: To compare the sensitivity of the hyperdense middle cerebral artery (MCA) sign between maximum intensity projection (MIP) and conventional averaged images in patients with acute focal neurological deficits with acute thromboembolic MCA occlusion (MCA occlusion group) and patients with acute focal neurological deficits without MCA occlusion (control group). MATERIALS AND METHODS: Initial computed tomography (CT) scans on admission were reconstructed with 5 mm thickness at every 3 mm interval for averaged and MIP images from 1 mm thickness non-contrast axial source images. Images were obtained from 30 cases each in the MCA occlusion and control groups. The CT values in the region of interests (ROIs) on the affected and unaffected sides of the MCA were compared. To compare CT values among subjects, the CT values were normalized by obtaining a ratio on the affected and unaffected sides, and the normalized CT values were analyzed using the receiver operating characteristic (ROC) curve. RESULTS: The hyperdense MCA sign was visually detected on MIP images in 90% cases and on 5 mm averaged images in only 57% cases in the MCA occlusion group. Based on the ROC analysis of the normalized ratio on the affected and unaffected sides, area under the curve of MIP image and averaged image was 0.941 and 0.655, respectively. On MIP images, the optimal threshold of the ratio on the affected and unaffected sides was 1.152 (sensitivity: 90.0%, and specificity: 93.3%). CONCLUSION: The hyperdense MCA sign sensitivity on 5 mm MIP images was significantly higher than that on conventional 5 mm averaged CT images. This could be useful for the early initiation of proper therapy for patients with acute focal neurological deficits.

3D dissimilar-siamese-u-net for hyperdense Middle cerebral artery sign segmentation.

The hyperdense middle cerebral artery sign (HMCAS) representing a thromboembolus has been declared as a vital CT finding for intravascular thrombus in the diagnosis of acute ischemia stroke. Early recognition of HMCAS can assist in patient triage and subsequent thrombolysis or thrombectomy treatment. A total of 624 annotated head non-contrast-enhanced CT (NCCT) image scans were retrospectively collected from multiple public hospitals in Hong Kong. In this study, we present a deep Dissimilar-Siamese-U-Net (DSU-Net) that is able to precisely segment the lesions by integrating Siamese and U-Net architectures. The proposed framework consists of twin sub-networks that allow inputs of left and right hemispheres in head NCCT images separately. The proposed Dissimilar block fully explores the feature representation of the differences between the bilateral hemispheres. Ablation studies were carried out to validate the performance of various components of the proposed DSU-Net. Our findings reveal that the proposed DSU-Net provides a novel approach for HMCAS automatic segmentation and it outperforms the baseline U-Net and many state-of-the-art models for clinical practice.

Hyperdense middle cerebral artery sign and response to combination of mechanical Thrombectomy plus intravenous thrombolysis in acute stroke patients.

BACKGROUND AND PURPOSE: Combining intra-arterial mechanical thrombectomy (IAMT) and intravenous thrombolysis (IVT) has shown to have an excellent recanalization rate and better clinical outcome in acute ischemic stroke (AIS) patients. Hyperdense middle cerebral artery sign (HMCAS) on pretreatment non-contrast head CT scan of AIS patients is one of the early ischemic radiological findings in middle cerebral artery territory AIS. We aimed to evaluate whether the presence of HMCAS predicts the outcome of AIS patients receiving combination therapy with IAMT and IVT. METHODS: We retrospectively reviewed medical records and cerebrovascular images of the patients treated with IAMT and IVT for AIS in our center. Patients with occlusion in the terminal internal carotid artery or middle cerebral artery on pretreatment CT angiogram of the head were included. Clinical outcome was compared between subjects with HMCAS and those without. Modified Rankin Score (mRS) and symptomatic intracranial hemorrhage (sICH) were used as measures of efficacy and safety, respectively. RESULTS: Of 93 patients, 46 (49%) had HMCAS on their initial head CT scan. Both groups had comparable baseline characteristics and stroke severity. After adjusting for age, NIHSS score, time from symptom onset to starting IVT, and history of diabetes mellitus in multivariate logistic regression analysis, there was no difference in terms of a poor outcome (mRS >2) (OR = 0.5 [CI 0.2-1.4], p = 0.188) or rate of sICH (OR = 3.3 [CI 0.6-19.0], p = 0.190) between the two groups. CONCLUSIONS: HMCAS is not a predictor of poor outcome in AIS patients receiving combination therapy with IAMT and IVT and does not affect treatment safety.

Hyperdense middle cerebral artery sign in large cerebral infarction.

OBJECTIVES: To evaluate if the hyperdense middle cerebral artery sign (HMCAS) is an imaging biomarker for hemorrhagic transformation (HT) and the functional outcome of patients with large cerebral infarctions without thrombolytic therapy. MATERIALS AND METHODS: The clinical and imaging data of 312 patients with large cerebral infarction without thrombolytic therapy were retrospectively analyzed. They were divided into patients who presented with HMCAS (n = 121) and those who did not (non-HMCAS[n = 168] patients), and the clinical data of the 2 groups were compared. This was a retrospective study. RESULTS: Of the 289 patients, 83(28.7%) developed HT. The incidence of atrial fibrillation, high homocysteine and admission NIHSS score at the time of admission was significantly higher in the HMCAS patients than in non-HMCAS patients (p < .05). The ASPECTS was significantly lower in HMCAS patients (t = -5.835, p < .001). The incidence of PH-2 and 3-month mRS score was also statistically significant higher in HMCAS patients (χ2  = 3.971, p = .046; χ2  = 5.653, p < .001, respectively). A sub-analysis showed HMCAS patients with HT were significantly older than non-HMCAS patients with HT (t = 2.473, p = .015). The incidence of atrial fibrillation and the 3-month mortality rate were higher in HMCAS patients with HT than in non-HMCAS patients with HT (χ2  = 3.944, p = .047; χ2  = 6.043, p = .014, respectively). Multiple logistic regression analysis showed HT was independently associated with HMCAS (adjusted OR/95% CI/p = 2.762/1.571-4.854/p < .001) and admission NIHSS score (adjusted OR/95% CI/p = 1.081/1.026-1.139/0.003). And HMCAS with HT was independently associated with length of HMCAS (adjusted OR/95% CI/p = 1.216/1.076-1.374/0.002). CONCLUSIONS: HMCAS in patients with a large cerebral infarction without thrombolytic therapy is an independent biomarker of HT. Length of HMCAS is also a marker of HT with lower ASPECTS in HMCAS patients.

The Hyperdense Middle Cerebral Artery Sign in Drip-and-Ship Models of Acute Stroke Management.

BACKGROUND: Large vessel occlusion (LVO) leads to debilitating stroke and responds modestly to recombinant tissue plasminogen activator (rt-TPA). Early thrombectomy improves functional outcomes in selected patients with proximal occlusion but it is not available in all medical facilities. The best imaging modality for triage in an acute stroke setting in drip-and-ship models is still the subject of debate. OBJECTIVES: We aimed to assess the diagnostic value of millimeter-sliced noncontrast computed tomography (NCCT) hyperdense middle cerebral artery sign (HMCAS) in itself or associated with clinical data for early detection of LVO in drip-and-ship models of acute stroke management. METHODS: NCCT of patients admitted to the Erasme Hospital, ULB, Brussels, Belgium, for suspicion of acute ischemic stroke between January 1 and July 31, 2017, were collected. Patients with brain hemorrhages were excluded, leading to 122 cases. The presence of HMCAS on NCCT was determined via visual assessment by 6 raters blinded to all other data. An independent rater assessed the presence of LVO on digital subtraction angiography imaging or contrast-enhanced CT angiography (CTA). The sensitivity, false-positive rate (FPR), and accuracy of HMCAS and the dot sign to detect LVO were calculated. The interobserver agreement of HMCAS was assessed using Gwet's AC1 coefficient. Then, on a separate occasion, the first 2 observers rereviewed all NCCT provided with clinical clues. The sensitivity, FPR, and accuracy of HMCAS were recalculated. RESULTS: HMCAS was found in 21% of the cases and a dot sign was found in 9%. The mean HMCAS sensitivity was 62% (95% CI 45-79%) and its accuracy was 86% (95% CI 79-92%) for detecting LVO. The interobserver reliability coefficient was 80% for HMCAS. Combined with clinical information, HMCAS sensitivity increased to 81% (95% CI 68-94; p = 0.041) and accuracy increased to 91% (95% CI 86-96%). CONCLUSION: When clinical data are provided, detection of HMCAS on thinly sliced NCCT could be enough to decide on transfer for thrombectomy in drip-and-ship models of acute stroke management, especially in situations where CTA is less available and referral centers for thrombectomy fewer and further apart.

Hyperdense large artery sign in meningitis: A marker of ominous thrombogenic potential of pneumococcus?

Hyperdensity in the middle cerebral artery (MCA) or posterior cerebral artery (PCA) on non-contrast head CT, suggests the presence of a thrombus inside these vessels, often referred to as the "MCA sign" or "PCA sign" respectively. These two signs are classically associated with strokes secondary to cardiovascular etiologies and are only infrequently reported with other types of stroke. Whereas stroke is a recognized complication of pneumococcal meningitis hyperdense large vessel sign (in this case a combination of MCA and PCA) has not been previously reported. We report a case of rapidly progressive pneumococcal meningitis that presented as acute stroke involving large vessels in the vicinity of the circle of Willis in a patient with a history of non-Hodgkin lymphoma (NHL) in remission for 6 years. This patient had received a week of high dose steroids before admission. Head CT scan on admission showed the presence of hyperdense MCA and PCA signs. The patient rapidly deteriorated and a follow-up head CT revealed diffuse brain edema and increased density in the basal cisterns without evidence of sub arachnoid hemorrhage. Tc99m exametazime brain flow scan showed no intracerebral blood flow both supra and infratentorially. Steptococcus pneumoniae, NHL cells and high-dose steroid use can upregulate tissue factor synthesis and may have led to a hypercoagulable state via activation of the extrinsic pathway in the large intracerbral arteries.