Non-contrast CT Brain Research Articles

Malignant Cerebral Venous Sinus Thrombosis in Polycythemia.

Malignant Cerebral Venous Sinus Thrombosis in Polycythemia.

Initial hospital management of patients with emergent large vessel occlusion (ELVO): report of the standards and guidelines committee of the Society of NeuroInterventional Surgery

ObjectiveTo summarize the current literature regarding the initial hospital management of patients with acute ischemic stroke (AIS) secondary to emergent large vessel occlusion (ELVO), and to offer recommendations designed to...

Abstract W P63: Intravenous Thrombolysis for Acute Ischemic Stroke in Nonagenarians

The safety and effectiveness of intravenous thrombolysis for acute ischemic stroke (AIS) has been established for populations older than 80 years of age . However, management of AIS in nonagenerians is not clear. Previous reports suggest that the rate of ICH after i.v. alteplase is not increased and the rate of early improvement is similar in nonagenerians compared to younger groups, but there is concern with overall mortality and functional outcomes. We report on 20 consecutive patients with AIS treated with i.v. alteplase within 3 hours of onset in two Comprehensive Stroke Centers in San Jose, CA. Methods: Patients were immediately evaluated by members of the Stroke Team of each hospital. . Patients were eligible if they had disabling neurological symptoms, no contraindications for i.v.alteplase and were independent in ADLs prior to the index event. Non-contrast CT brain scan, CT perfusion and CT angiography of head and neck were used to determine the presence of potentially salvageable brain. Results (Table): Mean age was 91 years (range 90 - 98 years). The initial NIHSS was 15.7 ± 6.8. The median NIHSS at hospital discharge was 7.4 ± 8.4 (p <0.001). The median door to needle time was 50.5 minutes (range 36 - 74 minutes). There was no hemorrhagic transformation and no in-hospital mortality. The overall mortality rate at 90 days was 30% (6 of 20 patients) and the rate of good outcome in survivors, defined as mRS ≤ 3 at 90 days was 35.7% (5 of 14 patients). Comment: Intravenous thrombolysis for ischemic stroke in nonagenerians is safe and effective, with good rates of immediate improvement. However, the l90 days mortality rate is high and the long term functional outcome is poor. This data can be useful in helping families make treatment decisions in the most elderly patients with acute ischemic stroke.

English

INTRODUCTION: The use of Non-contrast CT (NCCT) Brain is a frequent radiological study and often becoming part of the screening tools in the emergency departments (EDs) for traumatic complaints. AIMS AND OBJECTIVES: This study aimed to see whether ED Resident with 1 year of experience in casualty with no formal training in radiology working in the emergency department could interpret CT scans performed for trauma with adequate sensitivity and specificity to allow safe discharge. STUDY DESIGN: This was a Cross Sectional Observational study done on 200 patients presented to Emergency Department. CT scan (brain) done for head injury patients initial interpretation done by ED resident. The radiologist's interpretation was considered as reference for comparison. RESULTS: During the four months period, 200 patients required NCCT Brain for trauma were enrolled in our study. Emergency physician could diagnosis EDH, SDH and SAH with 100 % specificity; and with 85.7%, 87%, 82% sensitivity respectively. Midline shift on scan could be diagnosed with 200 % sensitivity and specificity by EM physician. However in case of hemorrhagic contusion (particularly in the frontal lobe), the sensitivity (92%) and specificity (87%) was slightly lower. Overall accuracy was 91.4966 %. The sensitivity for calling the scan positive or negative irrespective of differential diagnosis was 80%, and with specificity of 97.4%. If we exclude facial bone fractures, his sensitivity was still higher (92%) with higher specificity (98 %.) CONCLUSION: This study concludes, emergency physician can very well manage patients of head injury without need of radiologist for NCCT Brain interpretation and plan for conservative versus operative management in trauma victims in remote trauma centers. However, still sensitivity can be increased by formal training and more rotations in radiology department while doing their residency.

Evaluation of Virtual Noncontrast Images Obtained from Dual-Energy CTA for Diagnosing Subarachnoid Hemorrhage.

The virtual noncontrast images generated with iodine subtraction from dual-energy CTA images are expected to replace the true noncontrast images for radiation-dose reduction. This study assessed the feasibility of virtual noncontrast images for diagnosing SAH. Eighty-four patients with or without SAH underwent true noncontrast brain CT (the criterion standard for diagnosing SAH). Among them, 37 patients underwent an additional head dual-energy angiography, and the other patients underwent head and neck dual-energy angiography. Virtual noncontrast images were produced on a dedicated dual-energy postprocessing workstation and reconstructed in orientation and section width identical to those in true noncontrast images. The findings on the virtual noncontrast and true noncontrast images were compared at both the individual level and the lesion level. Image noise of the virtual noncontrast and true noncontrast images was also measured and compared. The volume CT dose index and dose-length product were recorded for the radiation-dose analysis. The sensitivity, specificity, positive predictive value, and negative predictive value of virtual noncontrast images at the individual level and the lesion level were 94.5%, 100%, 100%, 90.6% and 86.7%, 96.9%, 91.8%, 94.8%, respectively. The agreement in the diagnosis of SAH on true noncontrast and virtual noncontrast images reached 92.3% at the individual level and 85.1% at the lesion level. The virtual noncontrast images showed a higher image noise level. The volume CT dose index and dose-length product were obviously reduced without the true noncontrast brain CT scan. Virtual noncontrast images are a reliable tool for diagnosing SAH, with the advantage of reducing the radiation dose.

E-043 High-Grade Dural Arteriovenous Fistula Causing Subarachnoid Haemorrhage with Direct Visualization of the Rupture Site on CT Angiography

PurposeWe describe a case of subarachnoid haemorrhage caused by a high grade dural arteriovenous fistula (dAVF) with an identifiable venous rupture site on CT Angiography (CTA) in a patient with...

Carotid siphon calcification impact on revascularization and outcome in stroke intervention

ObjectiveThe degree of coronary artery calcification has been shown to predict outcomes in coronary artery disease. The impact of intracranial carotid artery calcification on the prognosis of acute ischemic stroke (AIS) is unknown. The authors sought to examine if the degree of intracranial carotid artery calcification influences reperfusion or outcomes in AIS intervention. MethodsAll anterior circulation large vessel occlusion AIS cases that underwent intra-arterial therapy from January 2009 to July 2012 were reviewed. Clinical and radiographic data were collected. Non-contrast brain CT scans were assigned a Calcium Extent Score (degree of calcification of the carotid wall circumference), Calcium Thickness Score (thickness of the calcified plaque), and total Carotid Siphon Calcium (CSC) Score (8-point scale). ResultsOne-hundred seventeen patients met inclusion criteria. The mean age was 65.4±15.6 years and 36% were male. Calcification was present in the intracranial carotid artery of 84 patients (71%). Inter-rater agreement for total CSC score was strong (Spearman's rho=0.883, p<0.001). The mean Calcium Extent Score was 1.5±1.3, Calcium Thickness Score 1.3±1.0 and total CSC Score 2.8±2.2. Reperfusion and mRS were not associated with CSC. Multivariate linear regression analysis revealed that older age, history of coronary disease and cervical internal carotid occlusion/near-occlusion were independently associated with higher total CSC scores. ConclusionExtensive calcification on the intracranial carotid artery does not have impact on reperfusion or clinical outcomes in AIS patients undergoing endovascular therapy. Higher CSC scores are associated with coronary artery disease, increasing age and cervical internal carotid artery occlusion/near-occlusion.

Uniform hyperdense vessels in non-contrast CT of brain: An unusual finding in plain CT scan diagnostic of polycythemia

Polycythemia is a blood disorder in which the proportion of blood occupied by red blood cells increases. It is reflected in raised hematocrit and hemoglobin values. Elevated hematocrit results in characteristic findings of increased attenuation of cerebral vessels and venous sinuses on unenhanced computed tomography. However, these imaging findings can closely mimic those of cerebral venous thrombosis, leading to diagnostic ambiguity. We present a case of polycythemia with typical features of hyperdense cerebral vasculature on non-enhanced computed tomography.

A pilot survey of decisions by acute medicine staff after thunderclap headache

Traditionally, neurologically pristine patients with a thunderclap headache are investigated with a non-contrast computed tomography (CT) brain scan, which if negative is followed by a lumbar puncture (LP) to exclude important secondary causes, particularly subarachnoid haemorrhage (SAH). However, misdiagnosis of such patients is still a cause of significant human and financial cost and a regular reason for medical litigation. This study explores the approach of emergency medicine and acute medicine clinicians to the investigation of a patient with thunderclap headache. Clinicians were invited to complete an online survey based on a clinical vignette of a 45-year-old man presenting with a thunderclap headache who had a pristine neurological examination. A total of 160 clinicians responded. The majority (89%) elected to perform a non-contrast CT brain as their first investigation, though five clinicians discharged the patient without investigation. If the CT was negative, only 84% would then proceed to LP, but 20% would undertake this investigation before 12 hours from headache onset. Most clinicians investigate neurologically intact patients with thunderclap headache following a CT/LP strategy, but deviations from recommended practice are common.

Peripheral air embolism

A 51-year-old man had venesection for haemochromatosis at his local clinic. After application of a tourniquet, a 14 gauge intravenous cannula was attached to intravenous tubing and a plastic collection bag, and inserted into a right antecubital fossa vein. Upon completion of the procedure, the tourniquet was released without previous clamping of the tubing system. The patient had a sudden gurgling sensation travelling up his arm, which was followed by severe central crushing chest pain with radiation to the jaw and left arm, severe dyspnoea, and left sided hemiparesis and dysphasia. Medical emergency services were contacted and the patient was transferred to hospital.On arrival he was hypoxic (oxygen saturation of 88% on room air). The left hemiplegia resolved within 15 minutes and the hypoxia, chest pain, and dyspnoea improved with application of high fl ow oxygen therapy. His initial ECG showed T-wave inversion inferiorly, which resolved within 12 hours of admission (appendix). Troponin I was raised at 0·14 μg/L (ref 0–0·08 μg/L) and fell to 0·08 6 hours later. Computed tomographic pulmonary angiography (CTPA) showed a fi lling defect in a subsegmental branch of the lingula (fi gure), which was suggestive of pul mon-ary embolism. Non-contrast CT brain scan was normal. 320-slice CT scan of the coronary arteries did not reveal any coronary abnormality but did show a patent foramen ovale. Transthoracic echocardiography with bubble study showed evidence of right-to-left shunting during both normal respiration and with Valsalva. Estimated baseline right heart pressures were normal. Transoesophageal echocardiogram confi rmed a patent foramen ovale and the passage of bubbles (appendix). The patient had an uncomplicated recovery and declined interventional closure of his patent foramen ovale.We postulate that air emboli were created when the tourniquet was released, resulting in pulmonary embolism with air emboli also crossing the patent foramen ovale to cause transient cerebral and myocardial ischaemia. Systemic air embolism and paradoxical air embolism through a cardiac defect have been well described and can occur in many types of vascular intervention.

Accuracy of Non-Contrast CT Brain Interpretation by Emergency Physicians: Acohort study.

To assess the accuracy of emergency physicians (EPs) in the interpretation of non-contrast CT Brain (NCCT Brain) by examining the inter rater reliability between EPs and radiology specialists. A four months prospective cohort study was conducted at emergency department of King Khalid University Hospital (KKUH), Riyadh, Saudi Arabia. We studied the daily performance of our EPs, and compared it to the radiological report issued within the week after. Data were analyzed by calculating sensitivity, specificity, accuracy and agreement (kappa statistic), using radiology report as the reference standard. Results : Out of 241 cases eligible for the study, 210 (87.14%) were concordant, and 31 (12.86%) were discordant. The agreement (kappa) was to be 0.64. Conclusion : We concluded that our EPs are moderately accurate at interpreting NCCT Brain studies. Further education and training programs were necessary for all our EPs to improve the accuracy. Further studies are required to determine the most cost-effective method of minimizing consequential misinterpretations.

Angiographic warning of hemorrhagic transformation after stent retriever thrombectomy procedure

This study reports cerebral angiographic findings observed after stent retriever thrombectomy that is suggestive of a higher risk of hemorrhagic transformation (HT). A woman aged 65–75 presented with a right...

Low Glomerular Filtration Rate Increases Hemorrhagic Transformation in Acute Ischemic Stroke

Background: Decreased glomerular filtration rate (GFR) can increase the risk of bleeding tendency and hemorrhagic stroke. However, the relationship between the levels of GFR and hemorrhagic transformation (HT) after acute ischemic stroke is largely unknown. The aim of this study was to assess whether GFR level is associated with HT in acute ischemic stroke. Methods: We reviewed 770 consecutive patients with acute ischemic stroke within 7 days from September 2007 to February 2012 in a prospective stroke registry database. We calculated the patient’s GFR using the Cockcroft-Gault equation, and divided them into 3 groups: ≥60, 30–59 and <30 ml/min/1.73 m². HTs were identified by follow-up computed tomography (CT) or magnetic resonance imaging, and were defined as (1) any degree of high density within the area of low attenuation of vascular territory on noncontrast brain CT, or (2) low-signal intensity area in gradient echo within high-signal intensity meaning acute infarct on diffusion-weighted imaging. Multivariable logistic regression analyses were used to estimate the risk of GFR for HT. Stratification analyses were done according to the presence of HT high risk factors: atrial fibrillation (AF), thrombolysis and large size infarction. Additional logistic regression model for symptomatic HTs was established with the same variables. Results: HTs were noted in 131 patients (17.0%) and symptomatic HTs in 63 patients (8.2%). In univariate analysis, HTs were more frequent in patients with AF (51.9 vs. 16.7%, p < 0.001) and large-size infarction (42.0 vs. 5.3%, p < 0.001). The risk of HT was associated with decreased GFR among 3 subgroups classified according to the value of estimated GFR: 49/394 (12.4%) in the GFR ≥60 group, 66/312 (21.2%) in the 30≤ GFR <59 group and 16/64 (25.0%) in the GFR <30 group (p = 0.002). We found a significant association between the GFR <30 group and HTs in acute ischemic stroke (OR 2.90; 95% CI 1.26–6.68, p = 0.012) after adjusting for other risk factors. Moreover, the incidence of HTs was higher in the subgroups without thrombolysis (OR 3.49; 95% CI 1.44–8.46) and without AF (OR 3.44; 95% CI 1.10–10.76). Decreased GFR also had a tendency of increasing symptomatic HTs (OR 2.39; 95% CI 0.72–7.94, p = 0.154). Conclusions: Low levels of GFR are associated with a high risk of HT after acute ischemic stroke. Further studies are needed to elucidate whether HT in the patients with renal insufficiency are related to a worse outcome after acute ischemic stroke.

Abstract TP239: Race and the Utilization of Diagnostic Procedures in the Emergency Department for Acute Stroke in the United States

Introduction: In 2007, the AHA recommended the use of the following diagnostic procedures immediately upon admission to the emergency department (ED) for all adult patients with suspected stroke: noncontrast brain CT or brain MRI, electrocardiogram, complete blood count (CBC) including platelets, cardiac enzymes and troponin, electrolytes, urea nitrogen, creatinine, serum glucose, prothrombin time and international normalized ratio (PT/INR), and oxygen saturation. We described the overall rate of utilization of these procedures and assessed for association with race using a national ED survey. Methods: We identified 308 ED visits for ischemic and spontaneous hemorrhagic strokes in adults 18 years representing 1.2 million stroke-related ED visits in the US using the National Hospital Ambulatory Medical Care Survey for years 2008-2009. The association between rates of utilization of diagnostic procedures and race was assessed using a Pearson chi-square test. Results: Overall the most common and least common diagnostic procedures performed were measurement of oxygen saturation (93%) and PT/INR (40%), respectively. There was no difference in use of CT/MRI (82.3% vs 82.7%, p =0.952), electrocardiogram (79.3% vs 80.7%, p =0.875), CBC (82.4% vs 93.9%, p =0.093), cardiac enzymes and troponin (55.7% vs 60.9%, p =0.523), electrolytes (57.4% vs 70.0%, p =0.153), urea nitrogen and creatinine (70.0% vs 68.5%, p =0.858), serum glucose (63.8% vs 66.8%, p =0.721), PTT/INR (37.3% vs 50.8%, p =0.139), and oxygen saturation (91.9% vs 98.7%, p =0.063) in blacks and whites, respectively. Conclusion: In terms of race, we found no significant difference in the rate of ED utilization of diagnostic procedures for acute stroke in the US. The overall rates of adherence to the 2007 AHA guidelines for diagnosis of acute stroke differed by diagnostic procedure. While there was almost universal measurement of oxygen saturation, less than half of acute stroke patients had a PT/INR analysis.

Abstract WP290: Endovascular Treatment Of In-hospital Strokes: An Open Book

INTRODUCTION: In-hospital stroke (IHS) presents a different treatment challenge than out of hospital stroke. IHS often has contraindication to IV tPA, such as such as recent surgery, MI, and use of anticoagulation. Intra-arterial therapy (IAT) with tPA and/or mechanical thrombectomy is an option for large vessel acute IHS with contraindications to or fail to recanalize with IV tPA, to restore cerebral perfusion. Objective: To assess the characteristics and outcomes of patients with in-hospital strokes large vessel occlusion who receive IAT. Methods: From our database of patients from 1/1/2008 to 12/31/2011 who had IAT for an acute stroke due to large vessel occlusion, in hospital strokes and out of hospital strokes were identified. Patient characteristics, imaging, and outcomes were retrospectively collected. Statistical analysis was performed on JMP 9.0. Result: 151 patients were included, 23 (15%) were in-hospital strokes (IHS) and 128 (85%) were out of hospital strokes (OHS). Initial median NIHSS of 17 and 16 respectively (p=0.3). IHS were frequently in the cardiology/CTS service (14, 60%) for CHF and cardiac valve repair (12, 52%). Other comorbidities present were atrial fibrillation (68%), hypertension (68%), and hyperlipidemia (56%). Seven (30%) were on warfarin prior to admission, but all had subtherapeutic INR. Three (13%) IHS received IV tPA. The time from last known well (LKW) to non-contrast CT brain was 80 min, and to CTA was 113 min in IHS, and 147 min and 229 min respectively in OHS (p = 0.0003). 20 (87%) had lesion in the anterior circulation. LKW to IAT recanalization was 248 min in IHS, compared to 375 min in OHS. Recanalization rate was 68% for IHS and 81% for OHS (p=0.2). Nine (39%) IHS had favorable mRS of 1 to 3 at 90 days, compared to 44 (34%) OHS, (p = 0.6). Despite faster recanalization time, there was no difference in the 90 day mortality of IHS v OHS (48% vs 30%, p = 0.1), and IHS had greater 1 year mortality (65% vs 30%, p = 0.005). Discussion: In-hospital strokes have higher mortality than out of hospital strokes. There is a role for IAT In carefully selected IHS with large vessel occlusion. A multicenter study is needed to reveal the characteristics of IHS patients who may benefit from IAT.

Acute Hemiparesis and Ipsilateral Supratentorial Lesion: Any Association?

A 59-year-old man presented with acute grade 4 left-sided pyramidal weakness, which improved spontaneously over a half-an-hour period to a remarkable degree. He had a history of longstanding hypertension and hyperlipidemia for which he was taking daily ramipril and atorvastatin. Otherwise, he denied any history of headache, previous focal neurological deficits, or seizures. He reported no loss of consciousness or external injuries. After examining the patient, an urgent non-contrast CT brain scan was carried out (Figure).

Cerebral Sinovenous Thrombosis Related to Iron Deficiency Anemia As a Result of Severe Menorrhagia: A Case Report

AbstractAbstract 5143Cerebral sinovenous thrombosis (CSVT) is a rare condition with a wide spectrum of non-specific symptoms, which makes it occasionally difficult to diagnose. CSVT has been associated with various etiologies including dehydration, hypercoagulable states, neoplasmic invasion of a venous sinus, intracranial and systemic infections, use of oral contraceptives, puerperium and pregnancy. Although iron deficiency anemia (IDA) has been reported as a cause of CSVT in several pediatric cases, this association is extremely rare. To our knowledge, IDA-associated CSVT in teenagers has been rarely reported.Here, we present the case of a 13-year old female with complete thrombosis of the vein of Galen, the straight sinus, and the left internal cerebral vein related to iron deficiency anemia as a result of severe menorrhagia. She initially presented with three-week history of headaches, nausea and vomiting. She was initially diagnosed and treated for bacterial sinusitis by her primary pediatrician, without symptom relief. She then suffered a syncopal episode, reason why she was evaluated at our institution. Initial laboratories revealed a slightly increased PT (15. 6 secs), hemoglobin of 5. 1 g/dL, MCV 63. 6 and D-dimer 1. 31. Non-contrast brain CT demonstrated no evidence of stroke, hemorrhage or mass. However, an abnormal hyperdensity in the straight sinus, inferior sagittal sinus, vein of Galen, and deep cerebral veins, were suggestive of venous thrombosis. Findings were then confirmed by brain MRI/MRV/MRA and CT angiogram. A bleeding work-up performed based on her history of heavy menses was normal. Her ferritin level was significantly decreased (6 ng/mL). Iron supplementation was initiated as well as progestin-only hormonal therapy for menstrual cycle regulation. The patient's clinical status improved back to baseline during her 8-day admission. She was discharged home on anticoagulation with scheduled follow up. Brain MRI/MRV six months later showed patency of the cerebral veins and dural venous sinuses.IDA should be considered as an underlying cause of CSVT in pediatric patients, particularly in patients with other risk factors for thrombosis including dehydration, regardless of their age. Early recognition and management of CSVT is critical to minimize the possibility of permanent neurologic damage. Physicians should be aware of the non-specific signs and symptoms of CSVT and should have a high index of suspicion in patients with anemia. Disclosures:No relevant conflicts of interest to declare.

Time Dependence of Reliability of Noncontrast Computed Tomography in Comparison to Computed Tomography Angiography Source Image in Acute Ischemic Stroke

There is no consensus on how the reliability and predictive ability of noncontrast computed tomography (NCCT) and computed tomography angiography source image (CTASI) change over time from acute ischemic stroke onset. We hypothesized that the reliability for detecting early ischemic changes (EIC) would be lower in early time periods and that changes identified on CTASI would be more reliable across examiners than changes identified on NCCT. To address this, we compared the relationships between CTASI, NCCT, and final infarct in patients with initial computed tomography (CT) imaging at different time points after stroke onset. Patients with acute ischemic stroke with proximal anterior circulation occlusions (internal carotid artery, middle carotid artery M1, proximal M2) from Calgary CT Angiography (CTA) database were studied. The cohort was categorized in four groups based on time from stroke onset to baseline NCCT/CTA: 0-90 mins (n = 69), 91-180 mins (n = 88), 181-360 mins (n = 46), and >360 mins (n = 58). Median scores of NCCT-Alberta Stroke Program Early CT Score (ASPECTS), CTASI ASPECTS, and follow-up ASPECTS among different time categories were compared. To determine reliability, a subsample of NCCT brain and CTASI were interpreted at separate sessions weeks apart by two neuroradiologists and two stroke neurologists in random order. Median and mean ASPECTS ratings on NCCT and CTASI were higher than final ASPECTS in each time category (P < 0·001 for all comparisons). CTASI ASPECTS was lower than NCCT ASPECTS in each time category, and differences were significant at 0-90 mins and 91-180 mins (P < 0·001). The least agreement among readers was in detection of EIC on NCCT brain in the ultra-early phase (<90 mins) [intraclass correlation coefficient (ICC) = 0·48. By contrast, there was excellent agreement on EIC on CTASI regardless of time period (ICC = 0·87-0·96). Using ASPECTS methodology, CTASI is more reliable than NCCT at predicting final infarct extent particularly in the early time windows.

Differentiation of Transverse Sinus Thrombosis From Congenitally Atretic Cerebral Transverse Sinus With CT

Transverse sinus thrombosis can have nonspecific clinical and radiographic signs. We hypothesized that the novel "sigmoid notch sign" (on head CT) can help differentiate transverse sinus thrombosis from a congenitally atretic sinus among individuals with absent signal in 1 transverse sinus by MR venography. We retrospectively evaluated 53 subjects with a unilaterally absent transverse sinus signal on MR venography. Eleven had true transverse sinus thrombosis and 42 had an atretic transverse sinus. Reviewers were trained in the sigmoid notch sign: "positive" if 1 of the sigmoid notches was asymmetrically smaller than the other, consistent with a congenitally absent transverse sinus on that side. This sign was scored on CT scans by 2 blinded reviewers to determine if signal dropout was clot or atretic sinus. A consensus rating was reached when the reviewers disagreed. Characteristics of the sigmoid notch sign as a diagnostic test were compared with a gold standard of full chart review by an independent reviewer. Each reviewer had a sensitivity of 91% (detecting 10 of 11 clots based on a negative sigmoid notch sign) and specificity of 71% to 81%; consensus specificity increased to 86% (36 of 42 individuals with an atretic sinus had a positive notch sign, detecting atretic sinuses based on presence of the sign). Asymmetries of the sigmoid notches on noncontrast brain CT is a very sensitive and specific measure of differentiating transverse sinus thrombosis from an atretic transverse sinus when absence of transverse sinus flow is visualized on MR venography.

Is it Post-Thrombolysis Intracranial Hemorrhage?

Intracranial hemorrhage is the commonest cause of hyperdensity on the non-contrast brain CT after thrombolysis with IV-TPA. This may range from minor petechial spots within the infarcted tissue to an extensive parenchymal hematoma. We present a patient who showed considerable clinical recovery after intravenous thrombolysis for acute ischemic stroke. However, his post-thrombolysis CT scan of the brain revealed a discrete hyperdensity in the infarcted region, due to extravasation of radio-contrast injected for CT angiography. His underlying end-stage renal failure probably contributed to a reduced rate of clearance of the contrast from his body. doi:10.4021/jnr83w