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Obscuration of the lentiform nucleus, (a) Subtle decrease in density of the lentiform nucleus on the right (arrows) compared with its normal counterpart on the left, (b) Follow-up scan 24 hours later shows infarct localized to putamen and posterior limb of the internal capsule.
Source publication
To determine the frequency of early computed tomographic (CT) findings of ischemia and their relationship to symptom duration and neurologic dysfunction within 3 hours of ischemic stroke.
The CT scans of 39 acute stroke patients were evaluated for signs of early ischemic change within 3 hours of symptom onset and without knowledge of the patient's...
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Delay in seeking medical attention after stroke symptom onset is the most important reason for low rates of thrombolytic use for ischemic stroke (IS) in the United States. This may be related to poor recognition of stroke symptoms, or to lack of awareness of time-sensitive stroke treatments. We describe public knowledge of t-PA as a treatment for I...
Oxidative stress as well as expression and activity of matrix metalloproteinase 9 (MMP-9) are rapidly enhanced after cerebral ischemia. The magnitude of these effects is related to stroke outcome. In human stroke, the extent of oxidative stress correlates well with increased MMP-9 expression. The aim of this study was to evaluate whether treatment...
Few healthcare centers in Brazil perform thrombolytic therapy for acute ischemic stroke (AIS) patients.
The aim of this study was to describe an interinstitutional protocol for the rapid identification and thrombolytic treatment of AIS patients at a public health hospital in a large Brazilian city.
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Citations
... Cortical (hemispherical) sulcal effacement is a relatively common sign, occurring in 33% of cases [20]. It indicates a partially superficial infarct, characterized by reduced contrast in the cortical sulci [18]. ...
... This phenomenon is caused by edema in the ischemic cortex [13]. When observed as an isolated sign, it indicates a better prognosis for intravenous thrombolytic therapy [19][20][21]. ...
Strokes are one of the global leading causes of physical or mental impairment and fatality, classified into hemorrhagic and ischemic strokes. Ischemic strokes happen when a thrombus blocks or plugs an artery and interrupts or reduces blood supply to the brain tissue. Deciding on the imaging modality which will be used for stroke detection depends on the expertise and availability of staff and the infrastructure of hospitals. Magnetic resonance imaging provides valuable information, and its sensitivity for smaller infarcts is greater, while computed tomography is more extensively used, since it can promptly exclude acute cerebral hemorrhages and is more favorable speed-wise. The aim of this article was to give information about the neuroimaging modalities used for the diagnosis and monitoring of ischemic strokes. We reviewed the available literature and presented the use of computed tomography, CT angiography, CT perfusion, magnetic resonance imaging, MR angiography and MR perfusion for the detection of ischemic strokes and their monitoring in different phases of stroke development.
... 4 In acute stroke, visualization of these minor signs of ischemia and infarction on MDCT is significant as these signs have diagnostic and prognostic importance. 5 The hyperdense middle cerebral artery sign (HMCAS) is the presence of high attenuation of the proximal segment of the middle cerebral artery (MCA) that is frequently accompanied by the M1 segment thrombosis of MCA. After a stroke of ischemic nature, it might be an initial diagnostic sign on MDCT. ...
Background
Hyperdense middle cerebral artery sign (HMCAS) on a non-enhanced multidetector computed tomography (MDCT) scan is considered an important radiological marker in detecting acute arterial thrombotic occlusion, and it is one of the earliest signs of ischemic cerebrovascular accident (CVA). This finding has been observed within 90 min of symptom onset. Modern approaches to patients with cerebral infarction emphasize early diagnosis and management.
Purpose
To determine the diagnostic accuracy of hyperdense artery signs in early detection of middle cerebral artery (MCA) infarction on non-contrast-enhanced MDCT scan using Magnetic Resonance Angiography (MRA) within 24 h as the gold standard for definitive diagnosis.
Method
A total of 140 patients aged 35–70 years, referred to the radiology department of Aga Khan University Hospital with clinical suspicion of acute cerebral infarction, were included. After clinical suspicion of acute infarction, the patient underwent an initial complete MDCT scan of the brain, which was performed using Aquilion ONE 640 slice MDCT (Toshiba Medical Systems, Japan). Consultant radiologists, with a minimum of 5 years of experience in MDCT brain imaging, interpreted the images. Follow-up examination with MRA within 24 h was performed to confirm the diagnosis of MCA infarction.
Results
Overall sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of HMCAS in the early detection of MCA infarction on non-contrast-enhanced MDCT scan using MRA as the gold standard for definitive diagnosis was 96.20%, 93.44%, 95.0%, 95.0%, and 95.0%, respectively.
Conclusion
This study concluded that the diagnostic accuracy of hyperdense artery signs in the early detection of MCA infarction on non-contrast-enhanced MDCT scans is very high.
... Following TBI, a hypodense lesion is associated with cerebral contusions or ischemic infarctions [16]. The early presence of an area of hypodensity after cerebral infarction is associated with increased severity of ischemia and is correlated with a worse outcome [23,28,40]. In this study, hemispheric hypodensity on the immediate postoperative CT scan was associated with a 2.5-fold higher likelihood of 6-month mortality. ...
Background
Primary decompressive craniectomy (DC) is considered for traumatic brain injury (TBI) patients with clinical deterioration, presenting large amounts of high-density lesions on computed tomography (CT). Postoperative CT findings may be suitable for prognostic evaluation. This study evaluated the radiographic predictors of clinical outcome and survival using pre- and postoperative CT scans of such patients.Methods
We enrolled 150 patients with moderate to severe TBI who underwent primary DC. They were divided into two groups based on the 6-month postoperative Glasgow Outcome Scale Extended scores (1–4, unfavorable; 5–8, favorable). Radiographic parameters, including hemorrhage type, location, presence of skull fracture, midline shifting, hemispheric diameter, effacement of cisterns, parenchymal hypodensity, and craniectomy size, were reviewed. Stepwise logistic regression analysis was used to identify the prognostic factors of clinical outcome and 6-month mortality.ResultsMultivariable logistic regression analysis revealed that age (odds ratio [OR] = 1.09; 95% confidence interval [CI] 1.032–1.151; p = 0.002), postoperative low density (OR = 12.58; 95% CI 1.247–126.829; p = 0.032), and postoperative effacement of the ambient cistern (OR = 14.52; 95% CI 2.234–94.351; p = 0.005) and the crural cistern (OR = 4.90; 95% CI 1.359–17.678; p = 0.015) were associated with unfavorable outcomes. Postoperative effacement of the crural cistern was the strongest predictor of 6-month mortality (OR = 8.93; 95% CI 2.747–29.054; p = 0.000).Conclusions
Hemispheric hypodensity and effacement of the crural and ambient cisterns on postoperative CT after primary DC seems to associate with poor outcome in patients with TBI.
... Stratification analysis showed that the patients with the highest sensitivity may have had the largest lesions. Since neurological dysfunction is closely associated with early CT signs (35) and ischemic volume (36), we speculate that large-scale hypodensities and other positive signs on CT may be an essential feature learned and transformed by the GAN model. The highest sensitivity was also found in patients receiving supportive care rather than those receiving recanalization therapies. ...
Background:
Difficulties in detecting brain lesions in acute ischemic stroke (AIS) have convinced researchers to use computed tomography (CT) to scan for and magnetic resonance imaging (MRI) to search for these lesions. This work aimed to develop a generative adversarial network (GAN) model for CT-to-MR image synthesis and evaluate reader performance with synthetic MRI (syn-MRI) in detecting brain lesions in suspected patients.
Methods:
Patients with primarily suspected AIS were randomly assigned to the training (n=140) or testing (n=53) set. Emergency CT and follow-up MR images in the training set were used to develop a GAN model to generate syn-MR images from the CT data in the testing set. The standard reference was the manual segmentations of follow-up MR images. Image similarity was evaluated between syn-MRI and the ground truth using a 4-grade visual rating scale, the peak signal-to-noise ratio (PSNR), and the structural similarity index measure (SSIM). Reader performance with syn-MRI and CT was evaluated and compared on a per-patient (patient detection) and per-lesion (lesion detection) basis. Paired t-tests or Wilcoxon signed-rank tests were used to compare reader performance in lesion detection between the syn-MRI and CT data.
Results:
Grade 2-4 brain lesions were observed on syn-MRI in 92.5% (49/53) of the patients, while the remaining syn-MRI data showed no lesions compared to the ground truth. The GAN model exhibited a weak PSNR of 24.30 dB but a favorable SSIM of 0.857. Compared with CT, syn-MRI led to an increase in the overall sensitivity from 38% (57/150) to 82% (123/150) in patient detection and from 4% (68/1,620) to 16% (262/1,620) in lesion detection (R=0.32, corrected P<0.001), but the specificity in patient detection decreased from 67% (6/9) to 33% (3/9). An additional 75% (70/93) of patients and 15% (77/517) of lesions missed on CT were detected on syn-MRI.
Conclusions:
The GAN model holds potential for generating synthetic MR images from noncontrast CT data and thus could help sensitively detect individuals among patients with suspected AIS. However, the image similarity performance of the model needs to be improved, and further expert discrimination is strongly recommended.
... 16 Observation of these subtle CT signs of infarction is important as these have diagnostic as well as prognostic value in the acute stroke setting. 25,26 Previous studies have demonstrated that observation of eye deviation is useful in identifying cerebral parenchymal hypoattenuation indicative of stroke, even in the absence of additional patient clinical data. 13 Any objective sign that may improve the sensitivity of CT in the detection of acute infarction warrants further investigation. ...
AIM: To determine a threshold at which the degree of ocular gaze deviation (OGD) on axial imaging is highly specific for the prediction of acute ischaemic stroke.
MATERIALS AND METHODS: A retrospective analysis of 517 patients who had received MRI with diffusion-weighted imaging (DWI) for suspected acute stroke was performed. The degree of OGD was measured in all patients and the presence and location of infarction determined. The difference in OGD between groups was compared using the independent t-test for normally distributed data and the Mann Whitney test for non-normal data. The sensitivity and specificity for degrees of OGD in the prediction of acute infarction was calculated using a receiver operating curve (ROC) analysis.

RESULTS: The imaging of 448 patients meeting the inclusion criteria was reviewed. Acute infarct was demonstrated in 34.8% (n1⁄4156). There was a significant difference in the degree of OGD between patients with an acute infarct and those without evidence of acute ischaemia (p<0.001). ROC curve analysis for OGD demonstrated area under the curve (AUC) 1⁄4 0.619 with increasing degrees of OGD more specific for acute infarct. OGD >11.95 had a sensitivity of 17% and specificity of 95.9% in predicting acute infarction.
CONCLUSION: Significant OGD>11.95 has a high specificity for acute infarct. This threshold may provide a helpful additional sign in the detection of subtle acute infarct, particularly on axial CT brain imaging.
... [1][2][3][4][5][6] Observation of these subtle clues to ischemia and infarction on CT is important because these signs have diagnostic as well as prognostic value in the acute stroke setting. 7,8 Increased density of a cerebral artery on noncontrast CT indicating the presence of intraluminal thrombus was one of the first early CT signs described in ischemic stroke patients. 9 Initial descriptions of the HMCA sign focused on M1 segment occlusions, which appear as linear streaks of hyper-density running along the imaging plane of axial CT slices, following the course of the M1 from its origin to the sylvian fissure. ...
The middle cerebral artery (MCA) "dot" sign consists of hyperdensity of an arterial structure, seen as a dot in the sylvian fissure. The MCA dot sign has been proposed to indicate thrombosis of M2 or M3 MCA branches, analogous to the hyperdense middle cerebral artery (HMCA) sign indicating M1 thrombosis. The MCA dot sign has not been validated previously against the gold standard of conventional cerebral angiography.
Noncontrast CT scans and immediately subsequent cerebral angiograms from 54 acute stroke patients within 8 hours of symptom onset were analyzed. CT films were inspected for the MCA dot sign and HMCA sign. Vascular findings on CT were compared with findings at angiography.
Mean patient age was 71 years; median National Institutes of Health Stroke Scale score was 16.5. Mean time from symptom onset to CT was 125 minutes, and that from CT to angiography was 117 minutes. All patients had arterial occlusion at angiography. Of the anterior circulation occlusions, M1 occlusions were noted in 28 patients, isolated M2 in 15, and isolated M3 in 4. One definite MCA dot sign was observed in 16.7% of patients, and an HMCA sign was observed in 13.9%. MCA dot sign performance in predicting the presence of M2 or M3 clot at angiography was as follows: sensitivity 38%, specificity 100%, positive predictive value 100%, negative predictive value 68%, and overall accuracy 73%.
The MCA dot sign is a highly specific and moderately sensitive indicator of acute thrombus in the M2/M3 MCA branches, as validated by catheter angiography. The MCA dot sign is a useful additional acute stroke CT marker.
... Albeit population-based studies [36,37] have shown that up to one-fourth of all stroke patients are managed at home or at long-term care institutions, the necessity of CT, if it is available, remains unequivocal. Brain scan adds significantly to the prediction of outcome made on clinical grounds and is considerably useful in optimizing treatment [38], as visible CT signs have been found to correlate with the degree of neurological disability [39] and to be an adverse prognostic indicator even after adjustment for stroke severity and time lapse between the stroke and the scan [40]. However, the value of CT performed later than 2 weeks from the event is questionable as the diagnosis is impossible in onethird of cerebral haemorrhages, the abnormalities being nonspecific or having completely disappeared [41,42]. ...
To develop a simple and reliable diagnostic tool for differentiation of cerebral infarction (CIF) from intracerebral haemorrhage (ICH) in order to aid clinicians to decide about starting antiplatelet therapy in settings where rapid access to computed tomography (CT) is lacking.
Thirty variables regarding each patient admitted with acute stroke were recorded and considered in a logistic regression analysis using ICH as end-point (internal study). CT was used as the golden standard. The score derived was validated with data from the next consecutive stroke patients and was compared with the three preexisting scores (external validation study).
Amongst 235 patients (119 males, mean age 70.6 +/- 11.2 years) of the internal study, 43 (18.3%) had ICH. Four independent correlates of ICH were identified and used for the derivation of the following integer-based scoring system: number of points=6 * (neurological deterioration within 3 h from admission) + 4 * (vomiting) + 4 * (WBC > 12 000) + 3 * (decreased level of consciousness). In the external study [168 patients, 85 males, mean age 70.2 +/- 10.8 years, 31 (18.5%) with ICH], when the cut-offs < or =3 points for CIF and > or =11 points for ICH were used, sensitivity, specificity, and positive and negative predictive values of the score for detection of stroke type were 97, 99, 97 and 99%, respectively; exceeding noticeably the three previously proposed systems.
The proposed model provides an easy to use tool for sufficiently accurate differentiation between haemorrhagic and nonhaemorrhagic stroke on the basis of information available to all physicians early after admission.
... Parenchymal hypoattenuation was defined as a region of abnormally decreased attenuation of brain structures relative to attenuation of other parts of the same structures or of the contralateral hemisphere. Focal brain swelling or mass effect was defined as any focal narrowing of the CSF space due to compression by adjacent structures, such as effacement of cortical sulci or ventricular compression (10). ...
Clinicians are insecure reading CT scans by using the one-third rule for acute middle cerebral artery stroke (1/3 MCA rule) before treating patients with recombinant tissue plasminogen activator. The 1/3 MCA rule is a poorly defined volumetric estimate of the size of cerebral infarction of the MCA. A 10-point quantitative topographic CT scan score, the Alberta Stroke Program Early CT Score (ASPECTS), is described and illustrated. A sharp increase in dependence and death occurs with an ASPECTS of 7 or less. We describe how to use ASPECTS and why it works with CT scans obtained on all commonly used axial baselines. We also describe interobserver reliability among clinicians from different specialties and with different experience in reading CT scans in the context of acute stroke.
The six physicians who developed ASPECTS answered a questionnaire on precisely how they interpret and use ASPECTS. The ASPECTS areas as interpreted by these physicians were compared with one another and with standards in the literature. kappa statistics were used to assess the interobserver reliability of ASPECTS versus the 1/3 MCA rule.
The exact methods of interpretation varied among the six individual observers, with either a 3:3 or 4:2 split on the specific questions. The overall interobserver agreement was good compared with that of the 1/3 MCA rule. Normal anatomic vascular and interobserver variations explain why ASPECTS can be applied with different CT axial baselines.
ASPECTS is a systematic, robust, and practical method that can be applied to different axial baselines. Clinician agreement is superior to that of the 1/3 MCA rule.
Purpose
Onset to imaging (OTI) time is a crucial factor in determining treatment eligibility for acute ischemic stroke patients, since the treatments are time-dependent. Patients with an unknown OTI time are often excluded from treatment, or advanced imaging is needed, which is not widely and readily available. As non-contrast CT (NCCT) is part of the standard stroke protocol, estimating OTI time using only NCCT would be valuable for patients with an unknown OTI time. Early ischemic signs (EISs) visible on NCCT might be fit for this purpose if an association between these signs and OTI time exists. This scoping review aims to provide an overview of the literature that associated OTI time with qualitative or quantitative EISs, including the hyperdense artery sign (HAS), decrease in grey matter-white matter differentiation, hypodensity, and mass effect.
Method
The prevalence of the EISs at specific OTI times is assessed, and previously presented associations between the EISs and OTI time are reported.
Results
The EIS prevalence varied between the studies. The HAS prevalence decreased after 6 hours since onset. The hypodensity prevalence increased with increasing OTI time. Studies quantifying the extent of hypodensity could distinguish patients within and beyond treatment time windows, indicating its potential to estimate OTI time. Finally, mass effect prevalence was seen more often at later OTI times.
Conclusions
It is concluded that, despite the high prevalence variability between studies, some associations between EISs and OTI time can be observed. These are potentially valuable in estimating OTI time and supporting treatment decisions.
Inflammatory response following acute cerebral ischaemia exacerbates neuronal damage and enlarges infarct extent. The role of adhesion molecules mediating attachment and migration of inflammatory cells within the ischaemic cerebrovascular region seems to be critical in the development of stroke-induced inflammatory reaction. Platelet endothelial cell adhesion molecule-1 (PECAM-1) present at cell to cell junction is required for transendothelial migration of leukocytes. We have recently demonstrated that ischaemic stroke patients displayed increased soluble PECAM-1 isoform (sPECAM-1) levels in serum and cerebrospinal fluid (CSF) within 24 h after the disease onset. The aims of the present study performed in the same group of 23 ischaemic stroke patients were to investigate the relationship between the levels of sPECAM-1 and the extent of early brain damage as well as stroke severity and its outcome. We have compared sPECAM-1 levels in serum and CSF samples obtained from the patients within 24 h of first-ever completed hemispheric ischaemic stroke with the volume of anatomically relevant early computed tomography (CT) of the brain hypodense areas as well as the neurological stroke severity estimated according to the Scandinavian Stroke Scale (SSS) scores and the functional disability assessed with the Barthel Index (B) scores. The significant correlation between sPECAM-1 levels both in sera and CSF of stroke subjects and the volume of early brain CT hypodense areas as well as both the SSS and the Bscores determined within 24 h of stroke and at 2nd week after the onset of stroke have been shown. The results indicate that early sPECAM-levels in serum and CSF are related to the volume of early brain CT hypodense areas as well as to severity of stroke and its outcome suggesting indirectly a possibility of PECAM-involvement in the detrimental inflammatory events accompanying ischaemic stroke.
