Noncontrast Cranial Computed Tomography Research Articles

Traumatic injury to the posterior fossa: a secondary analysis and description of case series from the NEXUS head injury dataset

Traumatic brain injuries involving the posterior fossa are rare and case reports indicate they often result in severe outcomes. We seek to describe characteristics and outcomes of traumatic posterior fossa injuries. We performed a planned secondary analysis of all patients with posterior fossa injuries enrolled in the NEXUS head computed tomography (CT) validation study dataset. The dataset includes prospectively collected data on all patients undergoing non-contrast cranial CT following blunt traumatic head injury from April 2006 to December 2015, at four emergency departments comprising community and university sites, as well as urban, suburban and rural settings in California (Antelope Valley Hospital, San Francisco General Hospital, UCLA Ronald Reagan Medical Center, UCSF Fresno Community Regional Medical Center). We classified each patient into one of three injury patterns: Type I-notable traumatic injuries primarily above the tentorium, with minimal posterior fossa involvement; Type II-notable traumatic injuries both above and within the posterior fossa; and Type III-notable traumatic injuries primarily within the posterior fossa. We extracted demographic data for each patient as well as physician assessments of the NEXUS head CT and Canadian Head CT rule clinical criteria, mechanisms of injury, patient outcomes, and the location and types of intracranial injuries sustained. Of 11,770 patients in the database, 184 (1.6%) had posterior fossa injuries on CT imaging. Mean age was 55.4 years (standard deviation 22.5 years, range 2-96 years); 131 (71.2%) were males. We identified 63 patients with Type I injuries, 87 with Type II injuries, and 34 Type III injuries. The most common mechanisms of injury were falls (41%), pedestrian vs automobile (15%), and motor vehicle collisions (13%). On presentation most patients had altered mental status (72%), abnormal behavior (53%), or a neurologic deficit (55%). The majority of individuals, 151 (82%), had clinically important injuries and 111 (60%) required neurosurgical intervention. The dispositions for the subjects included 52 deaths (28%), 49 (27%) patients discharged home, and 48 (26%) discharged to rehabilitation facilities. When compared to individuals with Type I and Type II injuries, patients with Type III injuries had lower mortality (6% vs 30% and 35%) and higher percentage of patients discharged home (60% vs 19% and 21%). Patients with Type I and II injury patterns (those that involve both the posterior fossa and supratentorium) experienced high mortality and disability. Patients with Type III injuries (isolated posterior fossa) had a better prognosis. None.

Using an artificial intelligence software improves emergency medicine physician intracranial haemorrhage detection to radiologist levels

BackgroundTools to increase the turnaround speed and accuracy of imaging reports could positively influence ED logistics. The Caire ICH is an artificial intelligence (AI) software developed for ED physicians to...

Association of serum occludin levels and perihematomal edema volumes in intracranial hemorrhage patients.

Perihematomal edema (PHE) is one of the severe secondary damages following intracranial hemorrhage (ICH). Studies showed that blood-brain barrier (BBB) injury contributes to the development of PHE. Previous studies showed that occludin protein is a potential biomarker of BBB injury. In the present study, we investigated whether the levels of serum occludin on admission are associated with PHE volumes in ICH patients. This cross-sectional study included 90ICH patients and 32 healthy controls.The volumes of hematoma and PHE were assessed using non-contrast cranial CT within 30 min of admission. Blood samples were drawn on admission, and the levels of baseline serum occludin were detected using enzyme-linked immunosorbent assay. Partial correlation analysis and multiple linear regression analysis were performed to evaluate the association between serum occludin levels and PHE volumes in ICH patients. The serum occludin levels in ICH patients were much higher than health controls (median 0.27 vs. 0.13 ng/mL, p < 0.001). At admission, 34 ICH patients (37.78%) had experienced a severe PHE (≥30 mL), and their serum occludin levels were higher compared to those with mild PHE (<30 mL) (0.78 vs. 0.21 ng/mL, p < 0.001). The area under the receiver operating characteristics curve (ROC) of serum occludin level in predicting severe PHE was 0.747 (95% confidence interval CI 0.644-0.832, p < 0.001). There was a significant positive correlation between serum occludin levels and PHE volumes (partial correlation r = 0.675, p < 0.001). Multiple linear regression analysis showed that serum occludin levels remained independently associated with the PHE volumes after adjusting other confounding factors. The present study showed that serum occludin levels at admission were independently correlated with PHE volumes in ICH patients, which may provide a biomarker indicating PHE volume change.

Can the sigmoid notch sign be used on cranial computed tomography to differentiate between thrombosis and hypoplasia of the cerebral transverse venous sinus?

In patients with headache, the distinction between transverse sinus (TS) atresia/hypoplasia and TS thrombosis in cranial magnetic resonance venography (MRV) may be misleading. In this study, we aimed to distinguish TS thrombosis from atretic or severely hypoplastic TS, with the help of cranial computed tomography (CT). Non-contrast cranial CT scans of 51 patients with no or severely thin signal on MRV were analyzed retrospectively using the bone window. Absence or asymmetry of the sigmoid notches on the CT predicted atretic or severe hypoplastic TS, and symmetry predicted thrombotic TS. Afterwards, it was investigated whether the patient's other imaging findings and confirmed diagnoses matched with the predictions. Of the 51 patients included in the study, 15 were diagnosed with TS thrombosis, and 36 were diagnosed with atretic/hypoplastic TS. All 36 of the congenital atresia/hypoplasia diagnoses were correctly predicted. Thrombosis was predicted correctly in 14 of 15 patients with TS thrombosis. In cranial CT, the symmetry or asymmetry of the sigmoid notch sign was examined, and it was found that the evaluation predicted with 93.3% sensitivity (95% confidence interval (CI): 68.05-99.83) and 100% specificity (95% CI: 90.26-100.00) the distinction between TS thrombosis and atretic/hypoplastic sinus. Symmetry or asymmetry of the sigmoid notch on CT is a reliable method that can be used to differentiate congenital atresia/hypoplasia from the TS thrombosis in patients with very thin or absent TS signal on the cranial MRV.

Pre-Existing Non-Disabling Encephalomalacia Confers Risk to Stroke Outcomes After Endovascular Treatment.

BackgroundPatients with previous stroke episodes tend to have poor outcomes after an endovascular treatment (EVT). Encephalomalacia (EM) is an objective indicator of previous strokes but has not been systematically investigated. The fundamental aim of this exploration is to investigate the effects of a pre-existing non-disabling EM on clinical outcomes after EVT.MethodsConsecutive patients undergoing an EVT due to the anterior circulation large vessel occlusion (LVO) strokes were enrolled in the study. The pre-existing EM was defined as the focal hypodense lesions (≥ 3 mm in maximum diameter) on a non-contrast cranial CT using axial images before EVT. The primary outcome was the 90-day functional assessment using the modified Rankin Scale (mRS) score. The safety outcome was the incidence of symptomatic intracranial hemorrhage (sICH) defined as any hemorrhage within 24 h after an EVT, which is responsible for an increase of ≥ 4 points in the score of National Institutes of Health Stroke Scale (NIHSS).ResultsOf the 433 patients analyzed in this investigation, a pre-existing non-disabling EM was observed in 106 (24.5%) patients. After adjusting for potential confounding factors, patients with contralateral EM (OR = 2.68, 95% CI = 1.13–6.31; P = 0.025) and with an EM+ > 20 mm in maximum diameter (OR = 2.21, 95% CI = 1.01–4.85; P =0.048) were substantially associated with unfavorable outcomes (mRS > 2). For the sICH, we did not observe any association with the pre-existing EM (P > 0.05).ConclusionsA pre-existing non-disabling EM is common and safe in patients undergoing EVT. However, a contralateral EM and the large size of EM may predict an unfavorable outcome at 90 days, which should receive more attention before EVT.

Accuracy of Noncontrast CT Brain in Detection of Cerebral Venous Sinus Thrombosis

Background and Purpose: Increasing concern of cerebral venous thrombosis due to treatable and curable causes of stroke. The diagnosis of cerebral venous sinus thrombosis is challenged due to nonspecific clinical symptomatology. Patients may present at an emergency room with a variety of neurological conditions such as severe headache, weakness, seizure, etc. Neuroimaging, particularly noncontrast cranial computed tomography (NCCT), is an investigation of choice in differentiation and triage the patients for further treatment. CT is sensitive in the detection of acute thrombosis or blood clots in all regions of the body. We hypothesize that NCCT might be sensitive to diagnose cerebral venous thrombosis immediately. Materials and Methods: Retrospectively review the electronic database of our patients, there are 27 patients with cerebral sinus venous thrombosis (SVT) and 4 patients with cerebral deep venous thrombosis (DVT). Other 79 patients present with clinically diagnosed cerebral venous thrombosis but the final result can exclude cerebral venous thrombosis. We use MR imaging and CT venography as the gold standard. Independently reviewed by two neuroradiologists for CT direct sign and CT indirect signs that suggest SVT or DVT. CT direct signs for SVT and DVT are the presence of hyperdensity in the sinus venous or deep venous system (cord sign, attenuated vein sign) and CT indirect signs are the changes in brain parenchyma (brain edema, hemorrhagic infarction). Results: Sensitivity and specificity of NCCT in detection attenuated vein sign and diagnosis DVT are 75% and 100% whereas the sensitivity and specificity of NCCT in detection cord sign and diagnosis SVT are 43.8% and 99.7% as respectively. Conclusions: NCCT might not sensitive in detection of SVT without CT direct sign which needs further investigation. However, NCCT might beneficial for emergency conditions such as DVT patients, cortical vein thrombosis and also in SVT patients with the positive CT direct sign.

Retrograde cerebral venous air embolism and the anatomical pathway of air bubbles: a case report

Pneumocephalus due to cerebral venous air embolism is an uncommon phenomenon. It results from retrograde progression of low weight air bubbles into dural venous sinuses during manipulation of a venous catheter, more frequently a central venous catheter through the subclavian and the jugular veins. However, it may also occur in relation with a peripheral intravenous catheter as in our case. We report a 91 year old female patient with congestive heart failure who had been examined in our emergency department two days previously due to dyspnea and received diuretic treatment through a peripheral intravenous line. She presented with vomiting and headache without obvious neurological deficits. Non-contrast cranial CT scan revealed wide spread punctate air bubbles inside and outside the cranial vault (pneumocephalus), within the venous system. The pneumocephalus was considered as iatrogenic due to the previous peripheral venous catheterization that resulted in retrograde migration of air bubbles through various venous connections into dural venous sinuses and extracranial veins. Since cerebral venous air embolism is a potentially serious complication of various medical procedures, it should be considered in differential diagnosis of nontraumatic headache and vomiting especially when there is a recent manipulation of venous lines. Cranial CT scan is helpful for early diagnosis.

Are modified Fisher Scale and bleeding pattern helpful predictors of neurological complications in non-aneurysmal subarachnoid hemorrhage?

Non-aneurysmal subarachnoid hemorrhage (NA-SAH) is a clinical-radiological entity with a different prognosis than aneurysmal SAH (A-SAH). The purpose of this study is to assess the predictive value of the modified Fisher Scale (mFS) for neurological complications in patients with this diagnosis. We recruited patients admitted at our hospital services between 2009 and 2017 who were diagnosed with spontaneous SAH, with either perimesencephalic (PM-SAH) or diffuse pattern (D-SAH), an initial negative angio-CT, and at least one digital subtraction angiography of brain vessels discarding underlying brain aneurysms or other vascular malformations. The retrospective observational study included 116 patients. The mean age was 54.4, and the sample included predominantly male subjects (62.9%). Hunt and Hess (HH) scores on admission ranged from 3 to 5 in 18.1% of patients. The prevalence of hydrocephalus requiring ventricular drainage was 18.1%. The prevalence of symptomatic vasospasm was 4.3%. A modified Rankin Scale (mRS) 0-2 at discharge was found in 95.6%. In a multivariate logistic regression for the presence of neurological complications including age, sex, admission HH 3-5 compared with < 3, mFS 4 compared with mFS < 4, D-SAH compared with PM-SAH, and mRS score at discharge of 0-2 compared with > 2, the only significant predictors were mFS 4 compared with mFS < 4 (OR 4.47 (95% CI 1.21, 16.66) p value = 0.03) and D-SAH compared with PM-SAH (OR 7.10 (95% CI 1.24, 40.8) p value = 0.03). In patients with NA-SAH, a mFS score of 4 and/or a D-SAH bleeding pattern in non-contrast cranial CT on admission predicted the development of relevant neurological complications.

Non-contrast Cranial Computed Tomography can Change the Emergency Management of Nontraumatic Seizure Patients

Objective: The abnormal cranial computed tomography (CT) findings can change the emergency management in 9 - 17% of first seizure patients in the emergency department (ED). The aim is to evaluate the utility of non-contrast cranial CT on emergency management of non-traumatic ED seizure patients. Methods: The patients’ charts, who had been coded G-40 according to ICD-10, between 2013 and 2015 were reviewed. All adult patients who applied to the ED with epileptic activity were included. The patients who had trauma, inefficacy in medical record and absence of CT report and detected as not to have seizure were excluded. The socio-demographic and seizure characteristics, CT indications and interpretations and emergency outcomes of patients were investigated. Data were pointed out as numbers, percentages and mean ± standard deviations. Pearson and Fisher’s chi-square tests were used for evaluating of categorical variables. p value < 0.05 was accepted as significant. Results: 814 patients were included. 55.7% were male. Mean age was 50 years (50.50 ± 20.26 years, 95% CI). 56.5% had chronic and 43.5% had first seizure activity. New abnormal CT findings were detected in 33.9% of first and in 11.7% of chronic seizure patients. Total abnormal CT findings ratio was 52%. 14.7% of first seizure and 7.2% of chronic seizure patients’ emergency managements were changed due to abnormal CT findings. Totally, 10.4% of all patients’ emergency management was detected as changed. Conclusions: In the ED, either in first or in chronic seizure activity, non-contrast cranial CT scan is a practice that may change the patients’ emergency managements.

A natural language processing algorithm to extract characteristics of subdural hematoma from head CT reports.

Subdural hematoma (SDH) is the most common form of traumatic intracranial hemorrhage, and radiographic characteristics of SDH are predictive of complications and patient outcomes. We created a natural language processing (NLP) algorithm to extract structured data from cranial computed tomography (CT) scan reports for patients with SDH. CT scan reports from patients with SDH were collected from a single center. All reports were based on cranial CT scan interpretations by board-certified attending radiologists. Reports were then coded by a pair of physicians for four variables: number of SDH, size of midline shift, thickness of largest SDH, and side of largest SDH. Inter-rater reliability was assessed. The annotated reports were divided into training (80%) and test (20%) datasets. Relevant information was extracted from text using a pattern-matching approach, due to the lack of a mention-level gold-standard corpus. Then, the NLP pipeline components were integrated using the Apache Unstructured Information Management Architecture. Output performance was measured as algorithm accuracy compared to the data coded by the two ED physicians. A total of 643 scans were extracted. The NLP algorithm accuracy was high: 0.84 for side of largest SDH, 0.88 for thickness of largest SDH, and 0.92 for size of midline shift. A NLP algorithm can structure key data from non-contrast head CT reports with high accuracy. The NLP is a potential tool to detect important radiographic findings from electronic health records, and, potentially, add decision support capabilities.

Role of computed tomography scan in assessment of skull fracture patterns among motorcycle road traffic accident patients in South Western Nigeria

Background: Commercial motorcycling is a common means of transportation in Nigeria, and motorcycle road traffic accidents (MCRTAs) are commonly associated with multiple skull fractures. Cranial computed tomography (CT) scan is the standard imaging modality of patients with head injury. Aim: The aim of this study is to describe the pattern of skull fractures on cranial CT scan in patients with head injury following MCRTA. Patients and Methods: This was a descriptive cross-sectional study conducted at the University College Hospital, Ibadan, between June and October 2016. Noncontrast cranial CT scan was performed on 190 patients who presented with head injury following MCRTAs. Results: Over half (n = 59.8%) of the patients were within the ages of 20–39 years with a mean age of 33 ± 14.37 years. A total of 183 patients did not use crash helmet at the time of accident, out of which 168 (n = 88.4%) sustained skull fractures. Six different skull fracture patterns were identified on cranial CT scan of these patients. The most common fracture pattern seen was the combined calvarial, facial, and base of skull fractures representing 22.1% while the least fracture pattern was the base of skull fracture (n = 4.7%). Most of the patients with calvarial fractures were without helmet at the time of injury (n = 98.3%) compared to 1.7% of patients who wore helmet at the time of injury. This was statistically significant (P = 0.040). Conclusion: This study further underscores the usefulness of cranial CT scan in identifying and evaluating patients with skull fractures following MCRTA in our environment, thus guiding proper medical and surgical management of such patients in a low-resource setting.

Dose reduction in paediatric cranial CT via iterative reconstruction: a clinical study in 78 patients

To assess how adaptive statistical iterative reconstruction (ASIR) contributes to dose reduction and affects image quality of non-contrast cranial computed tomography (cCT) in children. Non-contrast cranial CT acquired in 78 paediatric patients (age 0-12 years) were evaluated. The images were acquired and processed using four different protocols: Group A (control): 120kV, filtered back projection (FBP), n=18; Group B: 100kV, FBP, n=22; Group C: 100kV, scan and reconstruction performed with 20% ASIR, n=20; Group D1: 100kV, scan and reconstruction performed with 30% ASIR, n=18; Group D2: raw data from Group D1 reconstructed using a blending of 40% ASIR and 60% FBP, n=18. The effective dose was calculated and the image quality was assessed quantitatively and qualitatively. Compared to Group A, Groups C and D1/D2 showed a significant reduction of the dose-length product (DLP) by 34.4% and 64.4%, respectively. All experimental groups also showed significantly reduced qualitative levels of noise, contrast, and overall diagnosability. Diagnosis-related confidence grading showed Group C to be adequate for everyday clinical practice. Quantitative measures of Groups B and C were comparable to Group A with only few parameters compromised. Quantitative scores in Groups D1 and D2 were mainly lower compared to Group A, with Group D2 performing better than Group D1. Group D2 was considered adequate for follow-up imaging of severe acute events such as bleeding or hydrocephalus. The use of ASIR combined with low tube voltage may reduce radiation significantly while maintaining adequate image quality in non-contrast paediatric cCT.

Spontaneous Subarachnoid Hemorrhage: A Systematic Review and Meta-analysis Describing the Diagnostic Accuracy of History, Physical Examination, Imaging, and Lumbar Puncture With an Exploration of Test Thresholds.

Spontaneous subarachnoid hemorrhage (SAH) is a rare, but serious etiology of headache. The diagnosis of SAH is especially challenging in alert, neurologically intact patients, as missed or delayed diagnosis can be catastrophic. The objective was to perform a diagnostic accuracy systematic review and meta-analysis of history, physical examination, cerebrospinal fluid (CSF) tests, computed tomography (CT), and clinical decision rules for spontaneous SAH. A secondary objective was to delineate probability of disease thresholds for imaging and lumbar puncture (LP). PubMed, Embase, Scopus, and research meeting abstracts were searched up to June 2015 for studies of emergency department patients with acute headache clinically concerning for spontaneous SAH. QUADAS-2 was used to assess study quality and, when appropriate, meta-analysis was conducted using random effects models. Outcomes were sensitivity, specificity, and positive (LR+) and negative (LR-) likelihood ratios. To identify test and treatment thresholds, we employed the Pauker-Kassirer method with Bernstein test indication curves using the summary estimates of diagnostic accuracy. A total of 5,022 publications were identified, of which 122 underwent full-text review; 22 studies were included (average SAH prevalence = 7.5%). Diagnostic studies differed in assessment of history and physical examination findings, CT technology, analytical techniques used to identify xanthochromia, and criterion standards for SAH. Study quality by QUADAS-2 was variable; however, most had a relatively low risk of biases. A history of neck pain (LR+ = 4.1; 95% confidence interval [CI] = 2.2 to 7.6) and neck stiffness on physical examination (LR+ = 6.6; 95% CI = 4.0 to 11.0) were the individual findings most strongly associated with SAH. Combinations of findings may rule out SAH, yet promising clinical decision rules await external validation. Noncontrast cranial CT within 6 hours of headache onset accurately ruled in (LR+ = 230; 95% CI = 6 to 8,700) and ruled out SAH (LR- = 0.01; 95% CI = 0 to 0.04); CT beyond 6 hours had a LR- of 0.07 (95% CI = 0.01 to 0.61). CSF analyses had lower diagnostic accuracy, whether using red blood cell (RBC) count or xanthochromia. At a threshold RBC count of 1,000 × 10(6) /L, the LR+ was 5.7 (95% CI = 1.4 to 23) and LR- was 0.21 (95% CI = 0.03 to 1.7). Using the pooled estimates of diagnostic accuracy and testing risks and benefits, we estimate that LP only benefits CT-negative patients when the pre-LP probability of SAH is on the order of 5%, which corresponds to a pre-CT probability greater than 20%. Less than one in 10 headache patients concerning for SAH are ultimately diagnosed with SAH in recent studies. While certain symptoms and signs increase or decrease the likelihood of SAH, no single characteristic is sufficient to rule in or rule out SAH. Within 6 hours of symptom onset, noncontrast cranial CT is highly accurate, while a negative CT beyond 6 hours substantially reduces the likelihood of SAH. LP appears to benefit relatively few patients within a narrow pretest probability range. With improvements in CT technology and an expanding body of evidence, test thresholds for LP may become more precise, obviating the need for a post-CT LP in more acute headache patients. Existing SAH clinical decision rules await external validation, but offer the potential to identify subsets most likely to benefit from post-CT LP, angiography, or no further testing.

Hot Off the Press: An Observational Study of 2,248 Patients Presenting with Headache, Suggestive of Subarachnoid Hemorrhage, That Received a Lumbar Puncture Following a Normal Computed Tomography of the Head.

Headache is a very common emergency department (ED) chief complaint, representing about 2.8% of all visits in the United States.1 Sudden-onset, severe headache often warrants evaluation for etiologies with unacceptably high morbidity and lethality, including subarachnoid hemorrhage (SAH). Noncontrast head computed tomography (CT) as soon as possible after the onset of headache is the initial SAH diagnostic test of choice, but older studies indicate that up to one in three SAH patients were misdiagnosed during the initial ED encounter with subsequent treatment delays producing less optimal patient outcomes due to failure to perform or appropriately interpret lumbar puncture (LP) results in headache patients with a nondiagnostic CT.2 Early-generation CT studies reported inadequate sensitivities for the diagnosis of SAH so postimaging LP was the standard workup to adequately exclude SAH.3 The American College of Emergency Physicians (ACEP) Clinical Policy Statement for the evaluation of adult headache patients currently provide a Level B recommendation supporting LP following nondiagnostic noncontrast head CT to rule out SAH.4 Recent studies using newer-generation CT scanners demonstrate significantly improved sensitivities for detecting SAH if performed within 6 hours, rendering providers and clinical educators to question the benefit for LP in this population.5 This retrospective study evaluated the diagnostic yield of LP after a nondiagnostic head CT in patients presenting to one of six urban EDs in the United Kingdom. The primary outcome was the rate of diagnosis of SAH by LP after negative head CT. Over the course of 5 years, 2,248 patients were included, of whom 92 patients had a “positive” LP, according to spectrophotometric criteria established by the authors. Several limitations of this study were noted. First, the criteria for a positive LP in this study relied on spectrophotometric cerebrospinal fluid (CSF) analysis, which is not available or routinely performed in 97% of North American EDs.5 In fact, spectrophotometric assessment of xanthochromia has specificities as low as 29% and could actually increase further CT angiography and other more invasive downstream testing.6 Additionally, patients with inconclusive CSF results did not undergo uniform evaluation, since only two of six sites evaluated equivocal LPs and most these equivocal cases were not referred for additional definitive imaging. Using different thresholds to fully evaluate equivocal cases represents differential verification bias (double gold standard bias), which falsely elevates observed estimates of sensitivity and decreases estimates of specificity.7 In addition, the authors do not report any details about the delay between the onset of the headache and CT imaging or LP, which are both important because CT loses sensitivity after 6 hours and CSF bilirubin requires several hours to manifest following a sentinel bleed.5, 8 Finally, the investigators do not assess for potential temporal bias resulting from improvements in CT imaging quality and interpretation between 2006 and 2011.9 Among 2,248 patients with an initial high-resolution (16- to 64-slice) cranial CT, 92 patients had a positive LP of whom nine (0.04%) had an aneurysm subsequently identified. A significant proportion of LPs had inconclusive or uninterpretable results, 13 and 16%, respectively. The number of LPs needed to identify one aneurysm was 250 (1/0.004). This retrospective study of acute, nontraumatic adult headache patients with suspected SAH contradicts the ACEP Clinical Policy Statement and classical teaching that providers must evaluate CSF for xanthochromia or significant red blood cells following a negative noncontrast cranial CT to rule out SAH in acute headache patients. Routine LP following nondiagnostic cranial CT in patients with acute, nontraumatic headache yields more inconclusive and false-positive results than cases of SAH when evaluating for cerebral aneurysm-related sentinel bleeds. The number needed to LP to find one case of SAH in this scenario is 250, which should motivate shared decision-making with patients and more formal assessments of quantitative test–treatment thresholds in an era of increasingly sensitive CT imaging.

False-negative Interpretations of Cranial Computed Tomography in Aneurysmal Subarachnoid Hemorrhage.

Prior studies examining the sensitivity of cranial computed tomography (CT) for the detection of subarachnoid hemorrhage (SAH) have used the final radiology report as the reference standard. However, optimal sensitivity may have been underestimated due to misinterpretation of reportedly normal cranial CTs. This study aims to estimate the incidence of missed CT evidence of SAH among a cohort of patients with aneurysmal SAH (aSAH). We performed a retrospective chart review of emergency department (ED) encounters within an integrated health delivery system between January 2007 and June 2013 to identify patients diagnosed with aSAH. All initial noncontrast CTs from aSAH cases diagnosed by lumbar puncture (LP) and angiography following a reportedly normal noncontrast cranial CT (CT-negative aSAH) were then reviewed in a blinded, independent fashion by two board-certified neuroradiologists to assess for missed evidence of SAH. Reviewers rated the CT studies as having definite evidence of SAH, probable evidence of SAH, or no evidence of SAH. Control patients who underwent a negative evaluation for aSAH based on cranial CT and LP results were also included at random in the imaging review cohort. A total of 452 cases of aSAH were identified; 18 (4%) were cases of CT-negative aSAH. Of these, seven (39%) underwent cranial CT within 6 hours of headache onset, and two (11%) had their initial CTs formally interpreted by board-certified neuroradiologists. Blinded independent CT review revealed concordant agreement for either definite or probable evidence of SAH in nine of 18 (50%) cases overall and in five of the seven (71%) CTs performed within 6 hours of headache onset. Inter-rater agreement was 83% for definite SAH and 72% for either probable or definite SAH. CT evidence of SAH was frequently present but unrecognized according to the final radiology report in cases of presumed CT-negative aSAH. This finding may help explain some of the discordance between prior studies examining the sensitivity of cranial CT for SAH.

Automated assessment of early hypoxic brain edema in non-enhanced CT predicts outcome in patients after cardiac arrest

IntroductionEarly prediction of potential neurological recovery in patients after cardiac arrest is challenging. Recent studies suggest that the densitrometic gray-white matter ratio (GWR) determined from cranial computed tomography (CT) scans may be a reliable predictor of poor outcome. We evaluated an automated, rater independent method to determine GWR in CT as an early objective imaging predictor of clinical outcome. MethodsWe analyzed imaging data of 84 patients after cardiac arrest that underwent noncontrast CT within 24h after arrest. To determine GWR in CT we applied two methods using a recently published automated probabilistic gray-white matter segmentation algorithm (GWR_aut) and conventional manual measurements within gray-white regions of interest (GWR_man). Neurological outcome was graded by the cerebral performance category (CPC). As part of standard routine CPC was assessed by the treating physician in the intensive care unit at admission and at discharge to normal ward. The performance of GWR measures (automated and manual) to predict the binary clinical endpoints of poor (CPC3–5) and good outcome (CPC1–2) was assessed by ROC analysis with increasing discrimination thresholds. Results of GWR_aut were compared to GWR_man of two raters. ResultsOf 84 patients, 55 (65%) showed a poor outcome. ROC curve analysis revealed reliable outcome prediction of GWR_aut (AUC 0.860) and GWR_man (AUC 0.707 and 0.699, respectively). Predictive power of GWR_aut was higher than GWR_man by each rater (p=0.019 and p=0.021, respectively) at an optimal cut-off of 1.084 to predict poor outcome (optimal criterion with 92.7% sensitivity, 72.4% specificity). Interrater reliability of GWR_man by intra-class correlation coefficient (ICC) was moderate (0.551). ConclusionAutomated quantification of GWR in CT may be used as an objective observer-independent imaging marker for outcome in patients after cardiac arrest.

Automated assessment of early hypoxic brain edema in non-enhanced CT predicts outcome in patients after cardiac arrest

Abstract Introduction Early prediction of potential neurological recovery in patients after cardiac arrest is challenging. Recent studies suggest that the densitrometic gray-white matter ratio (GWR) determined from cranial computed tomography (CT) scans may be a reliable predictor of poor outcome. We evaluated an automated, rater independent method to determine GWR in CT as an early objective imaging predictor of clinical outcome. Methods We analyzed imaging data of 84 patients after cardiac arrest that underwent noncontrast CT within 24h after arrest. To determine GWR in CT we applied two methods using a recently published automated probabilistic gray-white matter segmentation algorithm (GWR_aut) and conventional manual measurements within gray-white regions of interest (GWR_man). Neurological outcome was graded by the cerebral performance category (CPC). As part of standard routine CPC was assessed by the treating physician in the intensive care unit at admission and at discharge to normal ward. The performance of GWR measures (automated and manual) to predict the binary clinical endpoints of poor (CPC3–5) and good outcome (CPC1–2) was assessed by ROC analysis with increasing discrimination thresholds. Results of GWR_aut were compared to GWR_man of two raters. Results Of 84 patients, 55 (65%) showed a poor outcome. ROC curve analysis revealed reliable outcome prediction of GWR_aut (AUC 0.860) and GWR_man (AUC 0.707 and 0.699, respectively). Predictive power of GWR_aut was higher than GWR_man by each rater ( p =0.019 and p =0.021, respectively) at an optimal cut-off of 1.084 to predict poor outcome (optimal criterion with 92.7% sensitivity, 72.4% specificity). Interrater reliability of GWR_man by intra-class correlation coefficient (ICC) was moderate (0.551). Conclusion Automated quantification of GWR in CT may be used as an objective observer-independent imaging marker for outcome in patients after cardiac arrest.

Posterior reversible encephalopathy syndrome during induction chemotherapy for acute myeloid leukaemia

A 52-year-old man, treated for an acute myelo-monocytic leukaemia, presented on day 22 of the second induction cycle an altered mental status with drowsiness, slurred speech and an unstable gait without focal neurological signs. A non-contrast cranial CT showed only non-specific findings, whereas a 3-T MR showed bilateral occipital, mainly subcortical oedema on fluid attenuated inversion recovery (Fig. A) and on T2-weighted (Fig. B) images, but with no restriction on diffusion-weighted imaging (not shown). These findings are compatible with a vasogenic oedema and allow the diagnosis of posterior reversible encephalopathy syndrome (PRES). A mild hypertension, noted 2 days before symptom onset, was treated with amlodipine. Serum electrolytes were normal. The mental alteration returned to normal within 2 days without additional treatment. Fourteen days later, the MRI showed complete resolution of the changes in the occipital region. Posterior reversible encephalopathy syndrome is a condition characterized by changes in mental status, headache, visual disturbances or other focal neurological deficiencies and/or seizures together with symmetrical vasogenic oedema in the posterior cerebral areas, initially described in the context of severe hypertension. Loss of autoregulatory mechanisms of the cerebral blood flow and endothelial damage are thought to be involved in the pathogenesis. A variety of medical conditions were identified as potential triggers including several chemotherapeutic agents, biological therapies (monoclonal antibodies and small molecules) or immunosuppressants. Fluid overload, a reduced renal function and an increased blood pressure are further risk factors for PRES during chemotherapy. Management includes correction of hypertension, antiepileptic therapy for seizures and optimal treatment of concomitant medical conditions as electrolyte disturbances or infections. Progression to cytotoxic oedema is a rare event, whereas in most cases, PRES resolves completely with no residual neurological deficiencies.

Rapid brain metastasis within 3 weeks

A 70-year-old man with a recent diagnosis of adenocarcinoma of the lung presented with right hand clumsiness. Examination found a slight weakness of the right arm. A non-contrast cranial CT...

Thrombolytic Therapy of Acute Stroke

Case 1 . A 65-year-old right-handed man with no history of heart disease presented to the emergency department with right-sided weakness and an inability to speak. His wife last saw him well 1 hour before his arrival. His ECG showed atrial fibrillation with a ventricular response of 100 bpm; his blood pressure was 175/88 mm Hg. He was alert, but he did not produce or comprehend speech. He did not blink to a threat presented in the right visual field. There was weakness of the right lower face and of the right arm and leg (National Institutes of Health Stroke Scale score, 15 of a possible 42). A noncontrast cranial computed tomography (CT) image showed no hemorrhage and no signs of early ischemia. Case 2 . A 39-year-old woman in good general health was found mumbling incoherently with left-sided weakness. She had been well minutes before. She was brought to a local hospital where she was noted to neglect her left personal space and to have left homonymous hemianopsia, rightward eye deviation, left lower facial weakness, and left arm and leg weakness (National Institutes of Health Stroke Scale score, 17). A head CT showed no evidence of hemorrhage or early ischemia, and she was given intravenous tissue-type plasminogen activator (tPA) before transfer to a comprehensive stroke center for consideration of intra-arterial therapy. On arrival at the receiving facility shortly after completion of the tPA infusion, her examination had not improved. A noncontrast head CT showed some loss of gray-white differentiation in the right parietal lobe (Figure 1A) and posterior insular cortex, and a CT angiogram showed abrupt cutoff of the right middle cerebral artery stem (Figure 1B). A conventional angiogram confirmed the right middle cerebral artery stem occlusion (Figure 1C). Figure 1. A, Noncontrast head computed tomography (CT) on …