Comprehensive imaging of ischemic stroke with multisection CT

Development of a cerebral CT perfusion phantom: A structured approach

INTRODUCTION

Computed tomography perfusion (CTP) imaging is crucial in diagnosing and managing vascular diseases, e.g, stroke. Differences in scanners and protocols may lead to different results, affecting clinical decision-making. Objective validation and evaluation of CTP imaging are therefore important. Perfusion phantoms are essential test objects to facilitate the validation and evaluation of perfusion imaging. Therefore, this study aimed to develop, validate and evaluate a brain perfusion phantom for the evaluation of cerebral CTP.

METHODS

A cerebral perfusion phantom was developed to evaluate CTP imaging of the brain using a workflow based on the Design Science Research Methodology. The reliability and repeatability of the phantom's perfusion parameters derived from the time-density curves (TDCs) in CTP were evaluated.

RESULTS

A 3D-printed modular perfusion phantom was developed, filled with sodium alginate beads, and connected to a pumping system to mimic microvasculature and flow dynamics. The phantom consisted of three compartments that simulated different states of perfusion. The phantom showed reliable TDCs, with a relative standard deviation of <6.6 % for peak intensity and time-to-peak (TTP) over two sets of five repeated experiments for all compartments, and repeatable TTP and mean transit time values with a repeatability coefficient of <2.3 s compared to the mean.

CONCLUSIONS

The developed perfusion phantom demonstrated high reliability and could be employed for investigating CTP imaging under various flow speeds. The presented workflow promotes transparency in the development, validation, and application of CTP phantoms, and facilitates cross-study comparisons through structured iterative development and unified evaluation metrics.

Diagnostic value of routine CT perfusion imaging for radiology residents

To evaluate whether incorporating CT perfusion imaging can significantly enhance diagnostic CT accuracy in stroke detection. Two 3rd-year residents (3rd of 5 years of residency) reviewed CT scans of 200 patients with suspected stroke, consisting of 104 patients with a proven stroke and a control group with 96 patients. They analyzed each patient in a blinded and randomized manner in two runs. In one session, they had only non-contrast CT and CT angiography available for diagnosis; in the other session at a later time point, an additional CT perfusion imaging was available. The performance achieved by the two readers was determined in terms of AUC (area under the curve), accuracy, sensitivity, specificity, positive and negative predictive value and Cohen's Kappa. Reader 1 achieved an AUC of 87.64% with the basic stroke-protocol vs. an AUC of 97.4% with an additional CT-perfusion given. Based on the DeLong test, these values differ significantly (p-value: 0.00017). Reader 2 achieved an AUC of 91.23% in basic stroke-protocol vs. an AUC of 96.42% with an additional CT-perfusion. These values also differ significantly (p-value: 0.02612).. The performance gain achieved with CT-perfusion is most evident in the decrease in the number of false classified cases (Reader 1: 24 to 5; Reader 2: 18 or 14 to 7) and the significant increase in Cohen's kappa. Our study shows that additional CT-perfusion imaging in stroke diagnosis significantly improves the diagnostic reliability of residents. Therefore, it should be further investigated whether perfusion imaging should be a general standard of initial stroke diagnosis no matter of the onset.

Study of Time-Resolved Dynamics in Turbid Medium Using a Single-Cavity Dual-Comb Laser

In measuring cerebral blood flow (CBF) noninvasively using optical techniques, diffusing-wave spectroscopy is often combined with near-infrared spectroscopy to obtain a reliable blood flow index. Measuring the blood flow index at a determined depth remains the ultimate goal. In this study, we present a simple approach using dual-comb lasers where we simultaneously measure the absorption coefficient (μa), the reduced scattering coefficient (μs '), and dynamic properties. This system can also effectively differentiate dynamics from various depths, which is crucial for analyzing multilayer dynamics. For CBF measurements, this capability is particularly valuable as it helps mitigate the influence of the scalp and skull, thereby enhancing the specificity of deep tissue.

Autoantibodies related to ataxia and other central nervous system manifestations of gluten enteropathy

Gluten ataxia and other central nervous system disorders could be linked to gluten enteropathy and related autoantibodies. In this narrative review, we focus on the various neuro-logical manifestations in patients with gluten sensitivity/celiac disease, immunological and autoimmune mechanisms of ataxia in connection to gluten sensitivity and the autoantibodies that could be used as a biomarker for diagnosing and following. We focused on the anti-gliadin antibodies, antibodies to different isoforms of tissue transglutaminase (TG) (anti-TG2, 3, and 6 antibodies), anti-glycine receptor antibodies, anti-glutamine acid decarboxylase antibodies, anti-deamidated gliadin peptides antibodies, etc. Most studies found a higher prevalence of these antibodies in patients with gluten sensitivity and neurological dysfunction, presented as different neurological disorders. We also discuss the role of a gluten-free diet on the clinical improvement of patients and also on imaging of these disorders.

Molecular Mechanisms of Ischemic Stroke: A Review Integrating Clinical Imaging and Therapeutic Perspectives

Ischemic stroke poses a significant global health challenge, necessitating ongoing exploration of its pathophysiology and treatment strategies. This comprehensive review integrates various aspects of ischemic stroke research, emphasizing crucial mechanisms, therapeutic approaches, and the role of clinical imaging in disease management. It discusses the multifaceted role of Netrin-1, highlighting its potential in promoting neurovascular repair and mitigating post-stroke neurological decline. It also examines the impact of blood-brain barrier permeability on stroke outcomes and explores alternative therapeutic targets such as statins and sphingosine-1-phosphate signaling. Neurocardiology investigations underscore the contribution of cardiac factors to post-stroke mortality, emphasizing the importance of understanding the brain-heart axis for targeted interventions. Additionally, the review advocates for early reperfusion and neuroprotective agents to counter-time-dependent excitotoxicity and inflammation, aiming to preserve tissue viability. Advanced imaging techniques, including DWI, PI, and MR angiography, are discussed for their role in evaluating ischemic penumbra evolution and guiding therapeutic decisions. By integrating molecular insights with imaging modalities, this interdisciplinary approach enhances our understanding of ischemic stroke and offers promising avenues for future research and clinical interventions to improve patient outcomes.

Influence of the integrity of circle of Willis on asymptomatic or mild patients with first diagnosed chronic internal carotid artery occlusion

BACKGROUND

In order to identify individuals with chronic internal carotid artery occlusion (CICAO), it is essential to understand the integrity of the circle of Willis (CoW). This understanding is important as it may determine the potential benefits of active medical and endovascular treatments.

PURPOSE

The objective of this study is to assess whether diminished integrity of the CoW can serve as a useful marker for identifying individuals with more severe impairment in cerebral blood perfusion and a higher incidence of cerebral infarction among asymptomatic or mildly affected patients with CICAO.

MATERIALS AND METHODS

We conducted a retrospective review of asymptomatic or mildly affected patients with newly diagnosed CICAO who did not receive reperfusion therapies. The categorization of patients into good or poor integrity groups was based on the assessment of CoW integrity using CTA. We evaluated the volume and value of prolonged time to peak (TTP) in both groups, as well as the occurrence of new cerebral infarctions. Our analysis involved multivariate regression and receiver operating characteristic (ROC) analysis.

RESULTS

Hemodynamic abnormalities characterized by prolonged TTP were observed in the affected side's blood supply region in all 38 patients. There was a notable difference in the volume and value of prolonged TTP between the two groups (P < 0.001). Correlation analyses based on CTP and CTA parameters revealed a negative relationship between CoW scores and both the abnormal volume (r = -0.624, P = 0.000) and value (r = -0.589, P = 0.000) of prolonged TTP. Upon multivariable adjustment, the independent predictors for new cerebral infarction and higher volume of prolonged TTP were solely the CoW status, with respective estimates of (b = 6.05; 95% confidence interval [CI]: 1.619, 22.619; P = 0.007) and (b = 35.486; 95% CI: 4.697, 268.088; P = 0.001).

CONCLUSION

Assessing the integrity of the CoW is crucial in evaluating abnormal perfusion in asymptomatic or mildly affected individuals who are newly diagnosed with CICAO and have not undergone reperfusion therapy.

Pictorial Review on Imaging Findings in Cerebral CTP in Patients with Acute Stroke and Its Mimics: A Primer for General Radiologists

The imaging evaluation of computed tomography (CT), CT angiography (CTA), and CT perfusion (CTP) is of crucial importance in the setting of each emergency department for suspected cerebrovascular impairment. A fast and clear assignment of characteristic imaging findings of acute stroke and its differential diagnoses is essential for every radiologist. Different entities can mimic clinical signs of an acute stroke, thus the knowledge and fast identification of stroke mimics is important. A fast and clear assignment is necessary for a correct diagnosis and a rapid initiation of appropriate therapy. This pictorial review describes the most common imaging findings in CTP with clinical signs for acute stroke or other acute neurological disorders. The knowledge of these pictograms is therefore essential and should also be addressed in training and further education of radiologists.

Organ perfusion during partial REBOA in haemorrhagic shock: dynamic 4D-CT analyses in swine

Resuscitative endovascular balloon occlusion of the aorta (REBOA) increases proximal blood pressure while inducing distal ischemia of visceral organs. The evaluation of distal ischemia severity during REBOA is a prerequisite for safe resuscitation of haemorrhagic shock patients with REBOA. We evaluated changes in blood flow and organ perfusion due to the degree of occlusion using dynamic 4D-computed tomography (CT). We compared the results with those of a previous study on euvolemic status. Delayed enhancement of the inferior vena cava (IVC) without retrograde flow was observed in the 4D-volume rendering images in the high-degree occlusion. The time-density curve (TDC) of the liver parenchyma (liver perfusion) and superior mesenteric vein (SMV) demonstrated a decreased peak density and a delayed peak in high-degree occlusion. The change rate of the area under the TDC of the liver and SMV decreased linearly as the degree of occlusion increased (PV, Y = -1.071*X + 106.8, r² = 0.972, P = 0.0003; liver, Y = -1.050*X + 101.8, r² = 0.933, P = 0.0017; SMV, Y = -0.985*X + 100.3, r² = 0.952, P = 0.0009). Dynamic 4D-CT revealed less severe IVC congestion during P-REBOA in haemorrhagic shock than in euvolemia. Analyses of TDC of the liver and SMV revealed a linear change in organ perfusion, regardless of intravascular volume.

A Preliminary Study of Alterations in Iron Disposal and Neural Activity in Ischemic Stroke

Purpose

The study aimed to evaluate the postrehabilitation changes in deep gray matter (DGM) nuclei, corticospinal tract (CST), and motor cortex area, involved in motor tasks in patients with ischemic stroke.

Methods

Three patients participated in this study, who had experienced an ischemic stroke on the left side of the brain. They underwent a standard rehabilitation program for four consecutive weeks, including transcranial direct current stimulation (tDCS), neuromuscular electrical stimulation (NMES), and occupational therapy. The patients' motor ability was evaluated by Fugl-Meyer assessment-upper extremity (FMA-UE) and Wolf motor function test (WMFT). Multimodal magnetic resonance imaging (MRI) was acquired from the patients by a 3 Tesla machine before and after the rehabilitation. The magnetic susceptibility changes were examined in DGM nuclei including the bilateral caudate (CA), putamen (PT), globus pallidus (GP), and thalamus (TH) using quantitative susceptibility mapping (QSM). Functional MRI (fMRI) in the motor cortex areas was acquired to evaluate the postrehab functional motor activity. The three-dimensional corticospinal tract (CST) was reconstructed using diffusion-weighted imaging (DWI) and diffusion tensor tractography (DTT), and the fractional anisotropy (FA) was measured along the tract. Ultimately, the relationship between the structural and functional changes was evaluated in CST and motor cortex.

Results

Postrehabilitation FMA-UE and WMFT scores increased for all patients compared to the prerehabilitation. QSM analysis revealed increasing in susceptibility values in GP and CA in all patients at the ipsilesional hemisphere. By fMRI analysis, the ipsilesional hemisphere demonstrated an increase in functional activity in motor areas for all 3 patients. In the ipsilesional hemisphere, the fractional anisotropy (FA) was increased in CST in two patients, while the mean diffusivity (MD) was decreased in CA in a patient, in PT and TH in another patient, and in PT in two patients.

Conclusion

This preliminary study demonstrates that the magnetic susceptibility may decrease at some ipsilesional DGM nuclei after tDCS, NMES, and occupational therapy for patients with ischemic stroke, suggesting a drop in the level of iron deposition, which may be associated with an increase in the level of activity in motor cortex after rehabilitation.

Performance of Automated RAPID Intracranial Hemorrhage Detection in Real-World Practice: A Single-Institution Experience

BACKGROUND AND PURPOSE

Intracranial hemorrhage (ICH) is a common finding in patients presenting to the emergency department with acute neurological symptoms. Noncontrast head computed tomography (NCCT) is the primary modality for assessment and detection of ICH in the acute setting. RAPID ICH software aims to automatically detect ICH on NCCT and was previously shown to have high accuracy when applied to a curated test data set. Here, we measured the test performance characteristics of RAPID ICH software in detecting ICH on NCCT performed in patients undergoing emergency stroke evaluation at a tertiary academic comprehensive stroke center.

MATERIALS AND METHODS

This retrospective study assessed consecutive patients over a 6-month period who presented with acute neurological symptoms suspicious for stroke and underwent NCCT with RAPID ICH postprocessing. RAPID ICH detection was compared with the interpretation of a reference standard comprising a board-certified or board-eligible neuroradiologist, or in cases of discrepancy, adjudicated by a consensus panel of 3 neuroradiologists. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of RAPID ICH for ICH detection were determined.

RESULTS

Three hundred seven NCCT scans were included in the study. RAPID ICH correctly identified 34 of 37 cases with ICH and 228 of 270 without ICH. RAPID ICH had a sensitivity of 91.9% (78.1%-98.3%), specificity of 84.4% (79.6%-88.6%), NPV of 98.7% (96.3%-99.6%), PPV of 44.7% (37.6%-52.1%), and overall accuracy of 85.3% (80.9%-89.1%).

CONCLUSIONS

In a real-world scenario, RAPID ICH software demonstrated high NPV but low PPV for the presence of ICH when evaluating possible stroke patients.

Experimental examination of radiation doses from cardiac and liver CT perfusion in a phantom study as a function of organ, age and sex

Cardiac and liver computed tomography (CT) perfusion has not been routinely implemented in the clinic and requires high radiation doses. The purpose of this study is to examine the radiation exposure and technical settings for cardiac and liver CT perfusion scans at different CT scanners. Two cardiac and three liver CT perfusion protocols were examined with the N1 LUNGMAN phantom at three multi-slice CT scanners: a single-source (I) and second- (II) and third-generation (III) dual-source CT scanners. Radiation doses were reported for the CT dose index (CTDI_vol) and dose-length product (DLP) and a standardised DLP (DLP_10cm) for cardiac and liver perfusion. The effective dose (ED_10cm) for a standardised scan length of 10 cm was estimated using conversion factors based on the International Commission on Radiological Protection (ICRP) 110 phantoms and tissue-weighting factors from ICRP 103. The proposed total lifetime attributable risk of developing cancer was determined as a function of organ, age and sex for adults. Radiation exposure for CTDI_vol, DLP/DLP_{10 cm}and ED_{10 cm}during CT perfusion was distributed as follows: for cardiac perfusion (II) 144 mGy, 1036 mGy·cm/1440 mGy·cm and 39 mSv, and (III) 28 mGy, 295 mGy·cm/279 mGy·cm and 8 mSv; for liver perfusion (I) 225 mGy, 3360 mGy·cm/2249 mGy·cm and 54 mSv, (II) 94 mGy, 1451 mGy·cm/937 mGy·cm and 22 mSv, and (III) 74 mGy, 1096 mGy·cm/739 mGy·cm and 18 mSv. The third-generation dual-source CT scanner applied the lowest doses. Proposed total lifetime attributable risk increased with decreasing age. Even though CT perfusion is a high-dose examination, we observed that new-generation CT scanners could achieve lower doses. There is a strong impact of organ, age and sex on lifetime attributable risk. Further investigations of the feasibility of these perfusion scans are required for clinical implementation.

Predictors of perfusion computed tomography alterations in stroke mimics attended as stroke code

BACKGROUND AND PURPOSE

Stroke mimics (SMs) account for a significant number of patients attended as stroke code (SC) with an increasing number over the years. Recent studies show perfusion computed tomography (PCT) alterations in some SMs, especially in seizures. The objective of our study was to evaluate the clinical characteristics and PCT alterations in SMs attended as SC in order to identify potential predictors of PCT alterations in SMs.

METHODS

A retrospective study was performed including all SC activations undergoing a multimodal CT study including non-enhanced computed tomography (CT), CT angiography and PCT, as part of our SC protocol, over 39 months. Patients with a final diagnosis of SM after complete diagnosis work-up were therefore selected. Clinical variables, diagnosis, PCT alteration patterns and type of map affected (T_max or time to peak, cerebral blood flow and cerebral blood volume) were registered.

RESULTS

Stroke mimics represent up to 16% (284/1761) of SCs with a complete multimodal study according to our series. Amongst SMs, 26% (74/284) showed PCT alterations. PCT abnormalities are more prevalent in seizures and status epilepticus and the main pattern is alteration of the time to peak map, of unilateral hemispheric distribution or of non-vascular territory. In our series, the independent predictors of alteration in PCT in SMs are aphasia, female sex and older age.

CONCLUSIONS

Perfusion computed tomography alterations can be found amongst almost a third of SMs attended as SC, especially older women presenting with aphasia with a final diagnosis of epileptic seizures and status epilepticus.

Impact of COVID-19 Pandemic on the Overall Diagnostic and Therapeutic Process for Patients of Emergency Department and Those with Acute Cerebrovascular Disease

(1) Background: During a pandemic, patients and processes in the emergency department (ED) change. These circumstances affect the length of stay (LOS) or degree of crowding in the ED. The processes for patients with acute critical illness, such as cerebrovascular disease (CVD), can be also delayed. Using the process mining (PM) method, this study aimed to evaluate LOS, ED processes for CVD, and delayed processes during the coronavirus disease 2019 (COVID-19) pandemic. (2) Methods: Data were collected from the Clinical Data Warehouse of a medical center. Phase 1 included patients who visited the ED before the COVID-19 outbreak. In Phase 2, post-COVID-19 ED patients were divided into the COVID-19 tested group (CTG) and COVID-19 not tested group (CNTG) according to whether polymerase chain reaction test was performed. We analyzed patients' ED processes before and after COVID-19 using the PM method. We analyzed patients with acute CVD separately to determine whether the process and LOS of patients with acute critical illness were changed or delayed. (3) Results: After the COVID-19 outbreak, the overall LOS was delayed and all processes in CTG patients were delayed. Registration to triage and triage were delayed in both CTG and CNTG patients. The brain imaging process for CTG patients with acute CVD was also delayed. (4) Conclusion: After a pandemic, some processes were changed, new processes were developed, and processes for patients with acute CVD who needed proper time management were not exempted.

Pathophysiologic mechanisms, neuroimaging and treatment in wake-up stroke

Wake-up stroke (WUS) or ischemic stroke occurring during sleep accounts for 14%-29.6% of all ischemic strokes. Management of WUS is complicated by its narrow therapeutic time window and attributable risk factors, which can affect the safety and efficacy of administering intravenous (IV) tissue plasminogen activator (t-PA). This manuscript will review risk factors of WUS, with a focus on obstructive sleep apnea, potential mechanisms of WUS, and evaluate studies assessing safety and efficacy of IV t-PA treatment in WUS patients guided by neuroimaging to estimate time of symptom onset. The authors used PubMed (1966 to March 2018) to search for the term "Wake-Up Stroke" cross-referenced with "pathophysiology," ''pathogenesis," "pathology," "magnetic resonance imaging," "obstructive sleep apnea," or "treatment." English language Papers were reviewed. Also reviewed were pertinent papers from the reference list of the above-matched manuscripts. Studies that focused only on acute Strokes with known-onset of symptoms were not reviewed. Literature showed several potential risk factors associated with increased risk of WUS. Although the onset of WUS is unknown, a few studies investigated the potential benefit of magnetic resonance imaging (MRI) in estimating the age of onset which encouraged conducting clinical trials assessing the efficacy of MRI-guided thrombolytic therapy in WUS.

CT for Treatment Selection in Acute Ischemic Stroke: A Code Stroke Primer

CT is the primary imaging modality used for selecting appropriate treatment in patients with acute stroke. Awareness of the typical findings, pearls, and pitfalls of CT image interpretation is therefore critical for radiologists, stroke neurologists, and emergency department providers to make accurate and timely decisions regarding both (a) immediate treatment with intravenous tissue plasminogen activator up to 4.5 hours after a stroke at primary stroke centers and (b) transfer of patients with large-vessel occlusion (LVO) at CT angiography to comprehensive stroke centers for endovascular thrombectomy (EVT) up to 24 hours after a stroke. Since the DAWN and DEFUSE 3 trials demonstrated the efficacy of EVT up to 24 hours after last seen well, CT angiography has become the operational standard for rapid accurate identification of intracranial LVO. A systematic approach to CT angiographic image interpretation is necessary and useful for rapid triage, and understanding common stroke syndromes can help speed vessel evaluation. Moreover, when diffusion-weighted MRI is unavailable, multiphase CT angiography of collateral vessels and source-image assessment or perfusion CT can be used to help estimate core infarct volume. Both have the potential to allow distinction of patients likely to benefit from EVT from those unlikely to benefit. This article reviews CT-based workup of ischemic stroke for making tPA and EVT treatment decisions and focuses on practical skills, interpretation challenges, mimics, and pitfalls.^©RSNA, 2019.

Imaging Ischemic and Hemorrhagic Disease of the Brain in Dogs

Strokes, both ischemic and hemorrhagic, are the most common underlying cause of acute, non-progressive encephalopathy in dogs. In effect, substantial information detailing the underlying causes and predisposing factors, affected vessels, imaging features, and outcomes based on location and extent of injury is available. The features of canine strokes on both computed tomography (CT) and magnetic resonance imaging (MRI) have been described in numerous studies. This summary article serves as a compilation of these various descriptions. Drawing from the established and emerging stroke evaluation sequences used in the investigation of strokes in humans, this summary describes all theoretically available sequences. Particular detail is given to logistics of image acquisition, description of imaging findings, and each sequence's advantages and disadvantages. As the imaging features of both forms of strokes are highly representative of the underlying pathophysiologic stages in the hours to months following stroke onset, the descriptions of strokes at various stages are also discussed. It is unlikely that canine strokes can be diagnosed within the same rapid time frame as human strokes, and therefore the opportunity for thrombolytic intervention in ischemic strokes is unattainable. However, a thorough understanding of the appearance of strokes at various stages can aid the clinician when presented with a patient that has developed a stroke in the days or weeks prior to evaluation. Additionally, investigation into new imaging techniques may increase the sensitivity and specificity of stroke diagnosis, as well as provide new ways to monitor strokes over time.

Organ ischemia during partial resuscitative endovascular balloon occlusion of the aorta: Dynamic 4D Computed tomography in swine

Resuscitative endovascular balloon occlusion of the aorta (REBOA) increases proximal pressure, and simultaneously induces distal ischemia. We aimed to evaluate organ ischemia during partial REBOA (P-REBOA) with computed tomography (CT) perfusion in a swine model. The maximum balloon volume was recorded as total REBOA when the distal pulse pressure ceased. The animals (n = 4) were scanned at each 20% of the maximum balloon volume, and time-density curve (TDC) were analysed at the aorta, portal vein (PV), liver parenchyma, and superior mesenteric vein (SMV, indicating mesenteric perfusion). The area under the TDC (AUTDC), the time to peak (TTP), and four-dimensional volume-rendering images (4D-VR) were evaluated. The TDC of the both upper and lower aorta showed an increased peak and delayed TTP. The TDC of the PV, liver, and SMV showed a decreased peak and delayed TTP. The dynamic 4D-CT analysis suggested that organ perfusion changes according to balloon volume. The AUTDC at the PV, liver, and SMV decreased linearly with balloon inflation percentage to the maximum volume. 4D-VR demonstrated the delay of the washout in the aorta and retrograde flow at the inferior vena cava in the highly occluded status.

Mapping the ischemic penumbra and predicting stroke progression in acute ischemic stroke: the overlooked role of susceptibility weighted imaging

Objectives

Asymmetrically prominent veins (APVs) detected on susceptibility weighted imaging (SWI) in acute stroke patients are assumed to signify compromised cerebral perfusion. We aimed to explore the role of APVs in identifying the ischemic penumbra and predicting stroke progression in acute stroke patients

Methods

Twenty patients with a middle cerebral artery ischemic infarction presenting within 24 h of symptoms onset underwent SWI following our standard MR stroke protocol imaging sequences which included diffusion-weighted imaging (DWI). Follow-up (FUP) FLAIR images were obtained at least 5 days after the initial MRI study. The Alberta Stroke Program Early CT Score (ASPECTS) was used to determine the initial infarct size, extent of APVs and final infarct size on initial DWI, SWI, and FUP images respectively. For each patient, SWI was compared with DWI images to determine match/mismatch of their respective ASPECTS values and calculate mismatch scores, whereas acute DWI findings were compared with follow-up images to identify infarct growth (IG) and calculate infarction growth scores (IGS).

Results

IG occurred in 6/10 patients with a positive DWI-SWI mismatch and in none of the patients without a positive DWI-SWI mismatch. A positive DWI/SWI mismatch was significantly associated with IG (χ² = 8.57, p = 0.0138, Cramer’s V = 0.65). A significant inverse correlation was found between SWI ASPECTS and IGS (r_s = − 0.702, p = 0.001). DWI-SWI mismatch scores were strongly correlated with IGS. (r_s = 0.788, p = 0.000)

Conclusion

A positive DWI-SWI mismatch is an indicator of the ischemic penumbra and a predictor of infarct expansion if left untreated.

Neurological complications after cardiac surgery: a retrospective case-control study of risk factors and outcome

Background

To evaluate incidence, risk factors, and outcomes of postoperative neurological complications in patients undergoing cardiac surgery.

Methods

A total of 2121 patients underwent cardiac surgery between August, 2008 and December, 2013; 91/2121 (4.3%) underwent brain computed tomography (70/91, 77%) or magnetic resonance imaging (21/91, 23%) scan because of major stroke (37/2121, 1.7%) and a spectrum of transient neurological episodes as well as transient ischemic attacks and delirium /psychosis/seizures (54/2121, 2.5%). The mean age was 65.3 ± 12.1 years and 60 (65.9%) were male. Variables were compared among study- and matched-patients (n = 113) without neurological deficits.

Results

A total of 37/2121 (1.7%) patients had imaging evidence of stroke. Radiological examinations were done 5.72 ± 3.6 days after surgery. Patients with and without imaging evidence of stroke had longer intensive care unit length of stay (LOS) (13.8 ± 14.7 and 12.9 ± 15 days vs. 5.7 ± 12.1 days, respectively (p < 0.001) and hospital LOS (53 ± 72.8 and 35.5 ± 29.8 days vs. 18.4 ± 29.2 days, respectively (p < 0.001) than the control group. The hospital mortality of patients with and without imaging evidence of stroke was higher than the control group (7/37 patients [19%], and 12/54 patients [22%] vs. 4/115 patients [3%], respectively (p < 0.001). Multivariate analysis showed that bilateral internal carotid artery stenosis of any grade (p < .001), and re-do operations (p = .013) increased the risk of postoperative neurological complications.

Conclusions

Neurological complications after cardiac surgery increase hospitalization and mortality even in patients without radiologic evidence of stroke. Bilateral internal carotid artery stenosis of any grade, suggesting a diffuse patient propensity toward atherosclerosis, and re-do operations increase the risk of postoperative neurological complications.

Interobserver agreement between senior radiology resident, neuroradiology fellow, and experienced neuroradiologist in the rating of Alberta Stroke Program Early Computed Tomography Score (ASPECTS)

PURPOSE

The distribution of ischemic changes caused by infarction of the middle cerebral artery (MCA) territories is usually measured using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS). The first interpreter of the brain computed tomography (CT) in the emergency department is the on-call radiology resident. The primary objective of this study was to describe the agreement of the ASPECTS performed retrospectively by the resident compared with expert raters. The second objective was to ascertain the appropriate window setting for early detection of acute ischemic stroke and good interobserver agreement between the interpreters.

METHODS

We identified consecutive patients presenting with hemiparesis or aphasia at the emergency department who underwent brain CT and CT angiography. Each scan was rated using ASPECTS by senior radiology resident, neuroradiology fellow, and later by consensus between two expert raters. Statistical analysis included determination of Cohen's kappa (κ) coefficient and intraclass correlation coefficient (ICC).

RESULTS

A total of 43 patients met our study criteria. Interobserver agreements for ASPECTS varied from 0.486 to 0.678 in Cohen's κ coefficient between consensus of two neuroradiologists and a neuroradiology fellow, and from 0.198 to 0.491 for consensus between two neuroradiologists and a senior radiology resident. ICC among three raters (expert consensus, neuroradiology fellow, and senior radiology resident), was very good when 8 HU window width and 32 HU center level setting was used.

CONCLUSION

ASPECTS varied among raters. However, when using a narrowed window setting for interpretation, interobserver agreement improved.

Multimodal computed tomography-guided intravenous rtPA for aborted stroke in a HIV-infected young man: a case report

Background

Human immunodeficiency virus (HIV) infection has been recognized as a risk factor for both ischemic and hemorrhagic stroke among young adults. However, information on the optimal management of HIV patients presenting with presumed acute ischemic stroke within the time window of intravenous recombinant tissue plasminogen activator (IV-rtPA) thrombolysis is limited. To the best of our knowledge, the use of multimodal computed tomography (CT)-based imaging to guide acute-phase treatment for patients with HIV infection has never been reported.

Case presentation

We report the clinical, imaging, and immunological features of a young man suffering from presumed acute ischemic stroke, initially without awareness of the presence of HIV infection. IV-rtPA guided by multimodal CT, including brain CT angiography (CTA) and CT perfusion (CTP), was administered at the emergency department. His symptoms were relieved, and there was no recurrence during the 2-month follow up.

Conclusions

Mutimodal CT is a valuable and promising tool for the early management of HIV-infected patients, especially for those presenting within the strict thrombolysis time window.

Intraprocedural 3D perfusion measurement during chemoembolisation with doxorubicin-eluting beads in liver metastases of malignant melanoma

OBJECTIVES

To study feasibility and validity of a new software application for intraprocedural assessment of perfusion during chemoembolisation of melanoma metastases.

METHODOLOGY

In a prospective phase-II trial, ten melanoma patients with liver-only metastases underwent chemoembolisation with doxorubicin-eluting beads (DEBDOX-TACE). Tumour perfusion was evaluated immediately before and after treatment at cone beam computer tomography (CBCT) using a new software application. For control and comparison, patients underwent perfusion measurement via contrast-enhanced multidetector CT (MDCT) before and after treatment.

RESULTS

CBCT showed 94.7 % reduction in perfusion in metastases after DEBDOX-TACE, whereas MDCT showed 96.8 %. Reduction in perfusion after treatment was statistically significant (p < 0.01) for both methods. The additional time needed for data acquisition during treatment was 5 min per case or less; the post-processing data analysis was 10 min or less. Perfusion imaging was associated with additional contrast agent and patient exposure to radiation (dose-length product [DLP]): 18 ml and 394 mGy*cm in CBCT and 100 ml and 446 mGy*cm in MDCT, respectively.

CONCLUSIONS

Reduction in perfusion of melanoma metastases after DEBDOX-TACE can be reliably assessed during the intervention via perfusion software at CBCT. Data acquisition and analysis require additional time but can be easily performed during the treatment.

KEY POINTS

• Tumour perfusion of melanoma metastases can be assessed at cone beam CT. • The software shows a significant decrease of tumour perfusion after DEBDOX-TACE. • Data acquisition and analysis require an acceptable additional time during the procedure. • CBCT requires less radiation exposure and contrast for perfusion study than MSCT. • This software can monitor the course of DEBDOX-TACE in melanoma metastases.

A tool to visualize and analyze perfusion data: Development and application of the R package "CTP"

BACKGROUND AND OBJECTIVE

Computed tomography perfusion (CTP) is a widely used imaging modality especially in neuroimaging. Despite this, CTP is often prohibitive due to the dearth of free/open-source software. This could have wide-ranging implications for instruction and research. We have implemented an online-available CTP tool built and run completely within the R computing environment.

METHODS

Called from within R, the user can select one of four different methods to construct a cerebral blood flow (CBF) map: (1) max-slope (2) singular value decomposition (3) block circulant singular value decomposition or (4) oscillation minimization singular value decomposition. The four methods are compared against a digital CBF phantom.

RESULTS

All four methods generate a CBF map, with the oscillation minimization technique giving the most accurate map.

CONCLUSIONS

We have constructed an easily accessible teaching and research tool to create a CBF map and made it freely available. We hope this tool will help facilitate understanding of the methods involved in constructing perfusion maps and be a valuable resource to future researchers.

Imaging of cerebral ischemic edema and neuronal death

PURPOSE

In acute cerebral ischemia, the assessment of irreversible injury is crucial for treatment decisions and the patient's prognosis. There is still uncertainty how imaging can safely differentiate reversible from irreversible ischemic brain tissue in the acute phase of stroke.

METHODS

We have searched PubMed and Google Scholar for experimental and clinical papers describing the pathology and pathophysiology of cerebral ischemia under controlled conditions.

RESULTS

Within the first 6 h of stroke onset, ischemic cell injury is subtle and hard to recognize under the microscope. Functional impairment is obvious, but can be induced by ischemic blood flow allowing recovery with flow restoration. The critical cerebral blood flow (CBF) threshold for irreversible injury is ~15 ml/100 g × min. Below this threshold, ischemic brain tissue takes up water in case of any residual capillary flow (ionic edema). Because tissue water content is linearly related to X-ray attenuation, computed tomography (CT) can detect and measure ionic edema and, thus, determine ischemic brain infarction. In contrast, diffusion-weighted magnetic resonance imaging (DWI) detects cytotoxic edema that develops at higher thresholds of ischemic CBF and is thus highly sensitive for milder levels of brain ischemia, but not specific for irreversible brain tissue injury.

CONCLUSION

CT and MRI are complimentary in the detection of ischemic stroke pathology and are valuable for treatment decisions.

Quantification of image contrast of infarcts on computed tomography scans

Introduction Accurate identification of infarcts in non-contrast computed tomography (NC-CT) scans of the brain is fundamental in the diagnosis and management of patients with stroke. Quantification of image contrast properties at the boundaries of ischemic infarct regions in NC-CT can contribute to a more precise manual or automatic delineation of these regions. Here we explore these properties quantitatively. Methods We retrospectively investigated 519 NC-CT studies of 425 patients with clinically confirmed ischemic strokes. The average and standard deviation (SD) of patients' age was 67.5 ± 12.4 years and the average(median)±SD time from symptoms onset to NC-CT examination was 27.4(12)±35.7 h. For every scan with an ischemic lesion identified by experts, the image contrast of the lesion vs. normal surrounding parenchyma was calculated as a difference of mean Hounsfield Unit (HU) of 1-5 consecutive voxels (the contrast window width) belonging to the lesion and to the parenchyma. This contrast was calculated at each single voxel of ischemic lesion boundaries (previously delineated by the experts) in horizontal and vertical directions in each image. The distributions of obtained horizontal, vertical and both contrasts combined were calculated among all 519 NC-CTs. Results The highest applicative contrast window width was identified as 5 voxels. The ischemic infarcts were found to be characterized by 6.60 HU, 8.28 HU and 7.55 HU mean values for distributions of horizontal, vertical and combined contrasts. Approximately 40-50% of the infarct boundary voxels were found to refer to the image contrast below 5 HU. Conclusion Low image contrast of ischemic lesions prevents accurate delineation of the infarcts in NC-CT.

CT Perfusion in Acute Lacunar Stroke: Detection Capabilities Based on Infarct Location

BACKGROUND AND PURPOSE

Recent studies demonstrated superiority of CTP to NCCT/CTA at detecting lacunar infarcts. This study aimed to assess CTP's capability to identify lacunae in different intracranial regions.

MATERIALS AND METHODS

Over 5.5 years, 1085 CTP examinations were retrospectively reviewed in patients with acute stroke symptoms with CTP within 12 hours and MRI within 7 days of symptom onset. Patients had infarcts ≤2 cm or no acute infarct on DWI; patients with concomitant infarcts >2 cm on DWI were excluded. CTP postprocessing was automated by a delay-corrected algorithm. Three blinded reviewers were given patient NIHSS scores and symptoms; infarcts were recorded based on NCCT/CTA, CTP (CBF, CBV, MTT, and TTP), and DWI.

RESULTS

One hundred thirteen patients met inclusion criteria (53.1% female). On DWI, lacunar infarcts were present in 37 of 113 (32.7%), and absent in 76 of 113 (67.3%). On CTP, lacunar infarcts typically appeared as abnormalities larger than infarct size on DWI. Interobserver κ for CTP ranged from 0.38 (CBF) (P < .0001) to 0.66 (TTP) (P < .0001); interobserver κ for DWI was 0.88 (P < 0.0001). In all intracranial regions, sensitivity of CTP ranged from 18.9% (CBV) to 48.7% (TTP); specificity ranged from 97.4% (CBF and TTP) to 98.7% (CBV and MTT). CTP's sensitivity was highest in the subcortical white matter with or without cortical involvement (21.7%-65.2%) followed by periventricular white matter (12.5%-37.5%); sensitivity in the thalami or basal ganglia was 0%.

CONCLUSIONS

CTP has low sensitivity and high specificity in identifying lacunar infarcts. Sensitivity is highest in the subcortical white matter with or without cortical involvement, but limited in the basal ganglia and thalami.

Neurovascular emergencies: imaging diagnosis and neurointerventional treatment

Neurovascular emergencies, consisting of acute ischemic stroke, non-traumatic aneurysmal subarachnoid hemorrhage, arteriovenous malformation, dural arteriovenous fistula, and carotid- cavernous fistula, can have an acute presentation to the emergency department. Radiologists should have an understanding of these processes and their imaging findings in order to provide a prompt and accurate diagnosis. Neurointerventional radiology plays a critical role in providing additional diagnostic information and potentially curative treatment. Understanding the grading scales used to evaluate and prognosticate these neurovascular emergencies can help expedite management for best possible patient outcomes.

First-ever ischemic stroke in elderly patients: predictors of functional outcome following carotid artery stenting

Age is an important risk factor for stroke, and carotid artery stenosis is the primary cause of first-ever ischemic stroke. Timely intervention with stenting procedures can effectively prevent secondary stroke; however, the impact of stenting on various periprocedural physical functionalities has never been thoroughly investigated. The primary aim of this study was to investigate whether prestenting characteristics were associated with long-term functional outcomes in patients presenting with first-ever ischemic stroke. The secondary aim was to investigate whether patient age was an important factor in outcomes following stenting, measured by the modified Rankin scale (mRS). In total, 144 consecutive patients with first-ever ischemic stroke who underwent carotid artery stenting from January 2010 to November 2014 were included. Clinical data were obtained by review of medical records. The Barthel index (BI) and mRS were used to assess disability before stenting and at 12-month follow-up. In total, 72/144 patients showed improvement (mRS[+]), 71 showed stationary and one showed deterioration in condition (mRS[-]). The prestenting parameters, ratio of cerebral blood volume (1.41 vs 1.2 for mRS[-] vs mRS[+]), BI (75 vs 85), and high-sensitivity C-reactive protein (hsCRP 5.0 vs 3.99), differed significantly between the two outcome groups (P<0.05). The internal carotid artery/common carotid artery ratio (P=0.011), BI (P=0.019), ipsilateral internal carotid artery resistance index (P=0.003), and HbA1c (P=0.039) were all factors significantly associated with patient age group. There was no significant association between age and poststenting outcome measured by mRS with 57% of patients in the ≥75 years age group showing mRS(-) and 43% showing mRS(+) (P=0.371). Our findings indicate that in our elderly patient series, carotid artery stenting may benefit a significant proportion of carotid stenotic patients regardless of age. Ratio of cerebral blood volume, BI, and admission hsCRP could serve as important predictors of mRS improvement and may facilitate differentiation of patients at baseline.

Optimization of the method for assessment of brain perfusion in humans using contrast-enhanced reflectometry: multidistance time-resolved measurements

The aim of the study was to determine optimal measurement conditions for assessment of brain perfusion with the use of optical contrast agent and time-resolved diffuse reflectometry in the near-infrared wavelength range. The source-detector separation at which the distribution of time of flights (DTOF) of photons provided useful information on the inflow of the contrast agent to the intracerebral brain tissue compartments was determined. Series of Monte Carlo simulations was performed in which the inflow and washout of the dye in extra- and intracerebral tissue compartments was modeled and the DTOFs were obtained at different source-detector separations. Furthermore, tests on diffuse phantoms were carried out using a time-resolved setup allowing the measurement of DTOFs at 16 source-detector separations. Finally, the setup was applied in experiments carried out on the heads of adult volunteers during intravenous injection of indocyanine green. Analysis of statistical moments of the measured DTOFs showed that the source-detector separation of 6 cm is recommended for monitoring of inflow of optical contrast to the intracerebral brain tissue compartments with the use of continuous wave reflectometry, whereas the separation of 4 cm is enough when the higher-order moments of DTOFs are available.

Technical prerequisites and imaging protocols for CT perfusion imaging in oncology

The aim of this review article is to define the technical prerequisites of modern state-of-the-art CT perfusion imaging in oncology at reasonable dose levels. The focus is mainly on abdominal and thoracic tumor imaging, as they pose the largest challenges with respect to attenuation and patient motion. We will show that low kV dynamic scanning in conjunction with detection technology optimized for low photon fluxes has the highest impact on reducing dose independently of other choices made in the protocol selection. We discuss, derived from relatively simple first principles, on what appropriate temporal sampling and total scan duration depend on and why optimized contrast medium injection protocols are also essential in limiting dose. Finally we will examine the possibility of simultaneously extracting standard morphological and functional information from one single 4D examination as a potential enabler for a more widespread use of dynamic contrast enhanced CT in oncology.

An ABC for decision making

The present study was aimed at proposing a systematic evaluation of cranial computed tomography, identifying the main aspects to be analyzed in order to facilitate the decision making process regarding diagnosis and management in emergency settings. The present descriptive study comprised a literature review at the following databases: Access Medicine and Access Emergency Medicine (McGraw- Hill Education); British Medical Journal Evidence Center; UptoDate; Bireme; PubMed; Lilacs; SciELO; ProQuest; Micromedex (Thomson Reuters); Embase. Once the literature review was completed, the authors identified the main diseases with tomographic repercussions and proposed the present system to evaluate cranial computed tomography images. An easy-to-memorize ABC system will facilitate the decision making in emergency settings, as it covers the main diseases encountered by intensivists and emergency physicians, and provides a sequential guidance about anatomical structures to be investigated as well as their respective alterations.

Processing and Interpretation Times of CT Angiogram and CT Perfusion in Stroke

Objective:

To determine the mean time for acquiring computed tomogram perfusion (CTP) and CT angiogram (CTA) images in acute stroke. To determine and compare processing and interpretation times amongst three groups of radiologists with varying degree of expertise: two radiology residents (Group I), two neuroradiology fellows (Group II) and four consultant neuroradiologists (Group III).

Methods:

The mean time of acquisition of CTA and CTP studies was calculated among ten patients presenting with acute stroke. All readers had to process the CTA and CTP images, interpret them (for presence or absence of thrombus and penumbra) and save them on the GE Advantage Windows workstation. The mean time for processing and interpreting these studies was calculated.

Results:

The mean time for acquisition of CTA and CTP studies in the ten patients was 14.6 ± 5.9 minutes. The time taken for CTA processing and interpretation in Groups I, II and III was 2.3 ± 1.3 min, 1.6 ± 0.4 min and 1.5 ± 0.7 min respectively. The time required for CTP processing and interpretation by the same groups was 5.2 ± 1.7 min, 4.5 ± 1.5 min and 4.1 ± 1.1 min respectively. There was a statistically significant difference of means between Groups I and III in the CTA and CTP processing and interpretation times (p=0.02, p=0.01 respectively) but no statistical difference between Groups I and II (p=0.15, p=0.22 respectively) or Groups II and III (p=0.31, p=0.30 respectively).

Conclusion:

The CTA and CTP studies can be performed, processed and interpreted quickly in acute stroke.

Potential of 80-kV high-resolution cone-beam CT imaging combined with an optimized protocol for neurological surgery

INTRODUCTION

With the development of computed tomography (CT) and magnetic resonance imaging (MRI), the use of conventional X-ray angiography including digital subtraction angiography (DSA) for diagnosis has decreased, as it is an invasive technique with a risk of neurological complications. However, X-ray angiography imaging technologies have progressed markedly, along with the development of endovascular treatments. A newly developed angiography technique using cone-beam CT (CBCT) technology provides higher spatial resolution than conventional CT. Herein, we describe the potential of this technology for neurosurgical operations with reference to clinical cases.

METHODS

Two hundred twenty-five patients who received 80-kV high-resolution CBCT from July 2011 to June 2014 for preoperative examinations were included in this study. For pathognomonical cases, images were taken with suitable reconstruction modes and contrast protocols. Cases were compared with intraoperative findings or images from other modalities.

RESULTS

We observed the following pathognomonical types: (1) imaging of the distal dural ring (DDR) and the surrounding structure for paraclinoid aneurysms, (2) imaging of thin blood vessels, and (3) imaging of both brain tumors and their surrounding anatomy. Our devised 80-kV high-resolution CBCT imaging system provided clear visualization of detailed anatomy when compared with other modalities in almost all cases. Only two cases provided poor visualization due to movement artifact.

CONCLUSION

Eighty-kilovolt high-resolution CBCT has the potential to provide detailed anatomy for neurosurgical operations when utilizing suitable modes and contrast protocols.

Feasibility of dynamic CT-based adenosine stress myocardial perfusion imaging to detect and differentiate ischemic and infarcted myocardium in an large experimental porcine animal model

The purpose of the study is feasibility of dynamic CT perfusion imaging to detect and differentiate ischemic and infarcted myocardium in a large porcine model. 12 Country pigs completed either implantation of a 75 % luminal coronary stenosis in the left anterior descending coronary artery simulating ischemia or balloon-occlusion inducing infarction. Dynamic CT-perfusion imaging (100 kV, 300 mAs), fluorescent microspheres, and histopathology were performed in all models. CT based myocardial blood flow (MBFCT), blood volume (MBVCT) and transit constant (Ktrans), as well as microsphere's based myocardial blood flow (MBFMic) were derived for each myocardial segment. According to histopathology or microsphere measurements, 20 myocardial segments were classified as infarcted and 23 were ischemic (12 and 14 %, respectively). Across all perfusion states, MBFCT strongly predicted MBFMic (β 0.88 ± 0.12, p < 0.0001). MBFCT, MBVCT, and Ktrans were significantly lower in ischemic/infarcted when compared to reference myocardium (all p < 0.01). Relative differences of all CT parameters between affected and non-affected myocardium were higher for infarcted when compared to ischemic segments under rest (48.4 vs. 22.6 % and 46.1 vs. 22.9 % for MBFCT, MBVCT, respectively). Under stress, MBFCT was significantly lower in infarcted than in ischemic myocardium (67.8 ± 26 vs. 88.2 ± 22 ml/100 ml/min, p = 0.002). In a large animal model, CT-derived parameters of myocardial perfusion may enable detection and differentiation of ischemic and infarcted myocardium.

Current Reperfusion Strategies for Acute Stroke

Stroke is the most common cause of permanent disability, the second most common cause of dementia, and the third most common cause of death in the Western world. The treatment of affected patients is a challenge because intravenous (IV) thrombolysis is often ineffective. IV thrombolysis on its own leads to a favorable clinical outcome in only 15% to 25% in patients with large-artery occlusion. Current reperfusion therapies enable high recanalization rates, high rate of favorable clinical outcome, and low complication rates. However, to achieve good clinical results, appropriate patient selection and the use of optimized stroke management system are obligate.

Pre- and Post-Angioplasty Perfusion CT with Acetazolamide Challenge in Patients with Unilateral Cerebrovascular Stenotic Disease

Objective

Perfusion computed tomography (PCT) has the ability to measure quantitative value and produce maps of mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV). We assessed cerebral hemodynamics by using these parameters and acetazolamide (ACZ) challenge for pre- and post-procedural evaluation in patients with unilateral cerebrovascular stenotic disease.

Methods

Thirty patients underwent pre-procedural PCT with ACZ challenge, and 24 patients (80%) was conducted follow up PCT after angioplasty with same protocol. The mean MTT, CBF, and CBV were measured and compared in both middle cerebral arterial (MCA) territories before and after ACZ challenge. Hemispheric ratio and percent change after ACZ challenge were calculated before and after angioplasty.

Results

The mean stenosis rate was 76.6%. Significant increases in MTT (32.6%, p=0.000) and significant decreases in CBF (-14.2%, p=0.000) were found in stenotic side MCA territories. After ACZ challenge, there were significant changes in MTT (37.4%, p=0.000), CBF (-13.1%, p=0.000), and CBV (-10.5%, p=0.001) in pre-procedural perfusion study. However, no significant increases were found in MTT, or decreases in CBF and CBV in post-procedural study. There were no significant changes after ACZ challenge also. In addition, the degrees of these changes (before and after ACZ challenge) were highly correlated with the stenotic degrees in pre-procedural perfusion study.

Conclusion

PCT with ACZ challenge appears to be a useful tool to assess the cerebral perfusion status especially in patients with unilateral symptomatic stenotic disease.

Prediction of Clinical Outcome in Acute Hemorrhagic Stroke from a Single CT Scan on Admission

Background:

From a single CT scan in primary intracerebral hemorrhage (ICH), clinical outcome can be assessed on admission by using the CT scan parameters.

Aims:

The study aims to find out how hematoma volume, location of stroke, midline shift, intraventricular extension of bleed and ventricle compression influence the clinical outcome in patients with acute ICH.

Materials and Methods:

Non-contrast CT scan was done on admission in hospital for every patient with acute hemorrhagic stroke and was analyzed accordingly. Clinical assessments were done in National Institute of Health Stroke Scale (NIHSS). Chi-square test and multiple logistic regression analysis were used for statistical analysis.

Results:

Mean hematoma volume associated with death before 30 days is 33.16 cm³ (P < 0.0001), with survived after 30 days is 15.45 cm³ (P < 0.0001), with NIHSS score ≥16 is 29.03 cm³ (P < 0.0001) and with NIHSS score <16 is 13.69 cm³ (P < 0.0001). Independent poor prognostic factors were hematoma volume > 30 cm³ (OR = 27.857), brain stem hemorrhage (OR = 6.000), intraventricular extension of bleed from other location (OR = 7.846), presence of ventricular compression alone (OR = 2.700) and in combination with midline shift of ≥ 5 mm (OR = 2.124).

Conclusions:

From a single CT scan during hospital admission, mortality and morbidity in next 30 days can be predicted. A hematoma volume >30 cm³, brain stem hematoma, intraventricular extension of bleed and ventricular compression along and with midline shift are associated with early mortality in ICH.

Acute-onset migrainous aura mimicking acute stroke: MR perfusion imaging features

BACKGROUND AND PURPOSE

In a very limited number of cases, acute migrainous aura may mimic acute brain infarction. The aim of this study was to recognize patterns of MR perfusion abnormalities in this presentation.

MATERIALS AND METHODS

One thousand eight hundred fifty MR imaging studies performed for the suspicion of acute brain infarction were analyzed retrospectively to detect patients with acute migrainous aura not from stroke. All patients were examined clinically by 2 neurologists and underwent a standard stroke MR imaging protocol, including PWI. Two radiologists reviewed the perfusion maps visually and quantitatively for the presence, distribution, and grade of perfusion abnormalities.

RESULTS

Among 1850 MR imaging studies, 20 (1.08%) patients were found to have acute migrainous aura. Hypoperfusion was found in 14/20 patients (70%) with delayed rMTT and TTP, decreased rCBF, and minimal decrease in rCBV. In contrast to the typical pattern in stroke, perfusion abnormalities were not limited to a single vascular territory but extended to >1. Bilateral hypoperfusion was seen in 3/14 cases. In 11/14 cases, hypoperfusion with a posterior predominance was found. TTP and rMTT were the best maps to depict perfusion changes at visual assessment, but also rCBF maps demonstrated significant hypoperfusion in quantitative analysis. In all patients, clinical and imaging follow-up findings were negative for stroke.

CONCLUSIONS

Acute migrainous aura is rare but important in the differential diagnosis among patients with the suspicion of acute brain infarction. Atypical stroke perfusion abnormalities can be seen in these patients.