Impact of early MRI in ischemic strokes beyond hyper-acute stage to improve patient outcomes, enable early discharge, and realize cost savings.

BACKGROUND: Early in-patient MR Imaging may assist in identifying stroke etiology, facilitating prompt secondary prevention for ischemic strokes (IS), and potentially enhancing patient outcomes. This study explores the impact of early in patient MRI on IS patient outcomes and healthcare resource use beyond the hyper-acute stage. METHODS: In this retrospective registry-based study, 771 admitted transient ischemic attack (TIA) and IS patients at Halifax's QEII Health Centre from 2015 to 2019 underwent in-patient MRI. Cohort was categorized into two groups based on MRI timing: early (within 48 h) and late. Logistic regression and Poisson log-linear models, adjusted for age, sex, stroke severity, acute stroke protocol (ASP) activation, thrombolytic, and thrombectomy, were employed to examine in-hospital, discharge, post-discharge, and healthcare resource utilization outcomes. RESULTS: Among the cohort, 39.6 % received early in-patient MRI. ASP activation and TIA were associated with a higher likelihood of receiving early MRI. Early MRI was independently associated with a lower rate of symptomatic changes in neurological status during hospitalization (adjusted odds ratio [OR], 0.42; 95 % confidence interval [CI], 0.20-0.88), higher odds of good functional outcomes at discharge (1.55; 1.11-2.16), lower rate of non-home discharge (0.65; 0.46-0.91), shorter length of stay (regression coefficient, 0.93; 95 % CI, 0.89-0.97), and reduced direct cost of hospitalization (0.77; 0.75-0.79). CONCLUSION: Early in-patient MRI utilization in IS patients post-hyper-acute stage was independently associated with improved patient outcomes and decreased healthcare resource utilization, underscoring the potential benefits of early MRI during in-patient management of IS. Further research, including randomized controlled trials, is warranted to validate these findings.

Role of cardiac computed tomography in hyperacute stroke assessment.

BACKGROUND: Incorporating cardiac CT with hyperacute stroke imaging may increase the yield for cardioembolic sources. It is not clarified whether stroke severity influences on rates of intracardiac thrombus. We aimed to investigate a National Institutes of Health Stroke Scale (NIHSS) threshold below which acute cardiac CT was unnecessary. METHODS: Consecutive patients with suspected stroke who underwent multimodal brain imaging and concurrent non-gated cardiac CT with delayed timing were prospectively recruited from 1st December 2020 to 30th November 2021. We performed receiver operating characteristics analysis of the NIHSS and intracardiac thrombus on hyperacute cardiac CT. RESULTS: A total of 314 patients were assessed (median age 69 years, 61% male). Final diagnoses were ischemic stroke (n=205; 132 etiology-confirmed stroke, independent of cardiac CT and 73 cryptogenic), transient ischemic attack (TIA) (n=21) and stroke-mimic syndromes (n=88). The total yield of cardiac CT was 8 intracardiac thrombus and 1 dissection. Cardiac CT identified an intracardiac thrombus in 6 (4.5%) with etiology-confirmed stroke, 2 (2.7%) with cryptogenic stroke, and none in patients with TIA or stroke-mimic. All of those with intracardiac thrombus had NIHSS ≥4 and this was the threshold below which hyperacute cardiac CT was not justified (sensitivity 100%, specificity 38%, positive predictive value 4.0%, negative predictive value 100%). CONCLUSIONS: A cutoff NIHSS ≥4 may be useful to stratify patients for cardiac CT in the hyperacute stroke setting to optimize its diagnostic yield and reduce additional radiation exposure.

Cerebral haemodynamics in symptomatic intracranial atherosclerotic disease: a narrative review of the assessment methods and clinical implications.

Intracranial atherosclerotic disease (ICAD) is a common cause of ischaemic stroke and transient ischaemic attack (TIA) with a high recurrence rate. It is often referred to as intracranial atherosclerotic stenosis (ICAS), when the plaque has caused significant narrowing of the vessel lumen. The lesion is usually considered 'symptomatic ICAD/ICAS' (sICAD/sICAS) when it has caused an ischaemic stroke or TIA. The severity of luminal stenosis has long been established as a prognostic factor for stroke relapse in sICAS. Yet, accumulating studies have also reported the important roles of plaque vulnerability, cerebral haemodynamics, collateral circulation, cerebral autoregulation and other factors in altering the stroke risks across patients with sICAS. In this review article, we focus on cerebral haemodynamics in sICAS. We reviewed imaging modalities/methods in assessing cerebral haemodynamics, the haemodynamic metrics provided by these methods and application of these methods in research and clinical practice. More importantly, we reviewed the significance of these haemodynamic features in governing the risk of stroke recurrence in sICAS. We also discussed other clinical implications of these haemodynamic features in sICAS, such as the associations with collateral recruitment and evolution of the lesion under medical treatment, and indications for more individualised blood pressure management for secondary stroke prevention. We then put forward some knowledge gaps and future directions on these topics.

Lost to Follow-Up: A Nationwide Analysis of Patients With Transient Ischemic Attack Discharged From Emergency Departments With Incomplete Imaging.

PURPOSE: Imaging guidelines for transient ischemic attack (TIA) recommend that patients undergo urgent brain and neurovascular imaging within 48 hours of symptom onset. Prior research suggests that most patients with TIA discharged from the emergency department (ED) do not complete recommended TIA imaging workup during their ED encounters. The purpose of this study was to determine the nationwide percentage of patients with TIA discharged from EDs with incomplete imaging workup who complete recommended imaging after discharge. METHODS: Patients discharged from EDs with the diagnosis of TIA were identified from the Medicare 5% sample for 2017 and 2018 using International Classification of Diseases, tenth rev, Clinical Modification codes. Imaging performed was identified using Current Procedural Terminology codes. Incomplete imaging workup was defined as a TIA encounter without cross-sectional brain, brain-vascular, and neck-vascular imaging performed within the subsequent 30 days of the initial ED encounter. Patient- and hospital-level factors associated with incomplete TIA imaging were analyzed in a multivariable logistic regression. RESULTS: In total, 6,346 consecutive TIA encounters were analyzed; 3,804 patients (59.9%) had complete TIA imaging workup during their ED encounters. Of the 2,542 patients discharged from EDs with incomplete imaging, 761 (29.9%) completed imaging during the subsequent 30 days after ED discharge. Among patients with TIA imaging workup completed after ED discharge, the median time to completion was 5 days. For patients discharged from EDs with incomplete imaging, the odds of incomplete TIA imaging at 30 days after discharge were highest for black (odds ratio, 1.84; 95% confidence interval, 1.27-2.66) and older (≥85 years of age; odds ratio, 2.41; 95% confidence interval, 1.78-3.26) patients. Reference values were age cohort 65 to 69 years; male gender; white race; no co-occurring diagnoses of hypertension, hyperlipidemia, or diabetes mellitus; household income > $63,029; hospital in the Northeast region; urban hospital location; hospital size > 400 beds; academically affiliated hospital; and facility with access to MRI. CONCLUSIONS: Most patients discharged from EDs with incomplete TIA imaging workup do not complete recommended imaging within 30 days after discharge.

Expedited and Comprehensive Management of Low-Risk TIA Patients in the Emergency Department is Safe and Less Costly.

OBJECTIVES: Transient ischemic attack (TIA) can be a warning sign of an impending stroke. The objective of our study is to assess the feasibility, safety, and cost savings of a comprehensive TIA protocol in the emergency room for low-risk TIA patients. MATERIALS AND METHODS: This is a retrospective, single-center cohort study performed at an academic comprehensive stroke center. We implemented an emergency department-based TIA protocol pathway for low-risk TIA patients (defined as ABCD2 score < 4 and without significant vessel stenosis) who were able to undergo vascular imaging and a brain MRI in the emergency room. Patients were set up with rapid outpatient follow-up in our stroke clinic and scheduled for an outpatient echocardiogram, if indicated. We compared this cohort to TIA patients admitted prior to the implementation of the TIA protocol who would have qualified. Outcomes of interest included length of stay, hospital cost, radiographic and echocardiogram findings, recurrent neurovascular events within 30 days, and final diagnosis. RESULTS: A total of 138 patients were assessed (65 patients in the pre-pathway cohort, 73 in the expedited, post-TIA pathway implementation cohort). Average time from MRI order to MRI end was 6.4 h compared to 2.3 h in the pre- and post-pathway cohorts, respectively (p < 0.0001). The average length of stay for the pre-pathway group was 28.8 h in the pre-pathway cohort compared to 7.7 h in the post-pathway cohort (p < 0.0001). There were no differences in neuroimaging or echocardiographic findings. There were no differences in the 30 days re-presentation for stroke or TIA or mortality between the two groups. The direct cost per TIA admission was $2,944.50 compared to $1,610.50 for TIA patients triaged through the pathway at our institution. CONCLUSIONS: This study demonstrates the feasibility, safety, and cost-savings of a comprehensive, emergency department-based TIA protocol. Further study is needed to confirm overall benefit of an expedited approach to TIA patient management and guide clinical practice recommendations.

Cost-Effectiveness of Advanced Neuroimaging for Transient and Minor Neurological Events in the Emergency Department.

Background Accurate diagnosis of patients with transient or minor neurological events can be challenging. Recent studies suggest that advanced neuroimaging can improve diagnostic accuracy in low-risk patients with transient or minor neurological symptoms, but a cost-effective emergency department diagnostic evaluation strategy remains uncertain. Methods and Results We constructed a decision-analytic model to evaluate 2 diagnostic evaluation strategies for patients with low-risk transient or minor neurological symptoms: (1) obtain advanced neuroimaging (magnetic resonance imaging brain and magnetic resonance angiography head and neck) on every patient or (2) current emergency department standard-of-care clinical evaluation with basic neuroimaging. Main probability variables were: proportion of patients with true ischemic events, strategy specificity and sensitivity, and recurrent stroke rate. Direct healthcare costs were included. We calculated incremental cost-effectiveness ratios, conducted sensitivity analyses, and evaluated various diagnostic test parameters primarily using a 1-year time horizon. Cost-effectiveness standards would be met if the incremental cost-effectiveness ratio was less than willingness to pay. We defined willingness to pay as $100 000 US dollars per quality-adjusted life year. Our primary and sensitivity analyses found that the advanced neuroimaging strategy was more cost-effective than emergency department standard of care. The incremental effectiveness of the advanced neuroimaging strategy was slightly less than the standard-of-care strategy, but the standard-of-care strategy was more costly. Potentially superior diagnostic approaches to the modeled advanced neuroimaging strategy would have to be >92% specific, >70% sensitive, and cost less than or equal to standard-of-care strategy's cost. Conclusions Obtaining advanced neuroimaging on emergency department patient with low-risk transient or minor neurological symptoms was the more cost-effective strategy in our model.

Variation in Organization of Transient Ischemic Attack Care in The Netherlands. A Nationwide Survey Study.

BACKGROUND: Previous research has shown the importance of urgent initiation of antiplatelet therapy after transient ischemic attack (TIA) to reduce the risk of stroke. Many hospitals in the Netherlands have therefore implemented rapid pathways for assessment of patients with TIA. Dutch stroke guidelines lack clear directives for organization of TIA assessment and thus allow for variation. The aim of this study was to investigate variation in organization of TIA assessment in Dutch hospitals. METHODS: One neurologist per hospital (of 88 Dutch hospitals) with special interest in stroke was invited to participate in a web-based survey addressing the organization, content, and timing of TIA assessment. RESULTS: Seventy (80%) neurologists completed the survey, all of whom reported performing TIA assessment in their hospital. There was considerable variation in the method of application and the location of assessment. In 10% of the hospitals, patients with TIA are always admitted to the ward. The content of diagnostics is fairly similar, but hospitals vary in the extent of cardiological workup. Almost all hospitals aim for a swift start of assessment as directed by guidelines, but access time differs. Eighty-six percent of respondents reported that antiplatelet therapy is usually initiated before assessment, based on history. CONCLUSIONS: This study showed variation in organization of TIA assessment in Dutch hospitals, especially regarding location within the hospital, time to assessment after announcement, and cardiological workup. Further research is needed to investigate implications of this variation for quality of care.

Impact of Hospital Admission for Patients with Transient Ischemic Attack.

OBJECTIVES: To determine the impact of admission among transient ischemic attack (TIA) patients in the emergency department (ED). STUDY DESIGN: Retrospective cohort study using national Veterans Health Administration data (2008). METHODS: We first analyzed whether admitted patients were discharged from the hospital with a diagnosis of TIA. We then analyzed whether admission was associated with a composite outcome (new stroke, new myocardial infarction, or death in the year after TIA) using multivariate logistic regression modeling with propensity score matching. RESULTS: Among 3623 patients assigned a diagnosis of TIA in the ED, 2118 (58%) were admitted to the hospital or placed in observation compared with 1505 (42%) who were discharged from the ED. Among the 2118 patients who were admitted, 903 (43% of admitted group) were discharged from the hospital with a diagnosis of TIA, and 548 (26% of admitted group) were discharged with a diagnosis of stroke. Admitted patients were more likely than nonadmitted patients to receive processes of care (i.e., brain imaging, carotid imaging, echocardiography). In matched analyses using propensity scores, the 1-year composite outcome in the admitted group (15.3%) was not lower than the discharged group (13.3%, OR 1.17 [.94-1.46], P = .17). CONCLUSIONS: Less than half of patients admitted with a diagnosis of TIA retained that diagnosis at hospital discharge. Although admitted patients were more likely to receive diagnostic procedures, we did not identify improvements in outcomes among admitted patients; however, evaluating care for patients with TIA is limited by the reliability of secondary data analysis.

White Matter Imaging Correlates of Early Cognitive Impairment Detected by the Montreal Cognitive Assessment After Transient Ischemic Attack and Minor Stroke.

BACKGROUND AND PURPOSE: Among screening tools for cognitive impairment in large cohorts, the Montreal Cognitive Assessment (MoCA) seems to be more sensitive to early cognitive impairment than the Mini-Mental State Examination (MMSE), particularly after transient ischemic attack or minor stroke. We reasoned that if MoCA-detected early cognitive impairment is pathologically significant, then it should be specifically associated with the presence of white matter hyperintensities (WMHs) and reduced fractional anisotropy (FA) on magnetic resonance imaging. METHODS: Consecutive eligible patients with transient ischemic attack or minor stroke (Oxford Vascular Study) underwent magnetic resonance imaging and cognitive assessment. We correlated MoCA and MMSE scores with WMH and FA, then specifically studied patients with low MoCA and normal MMSE. RESULTS: Among 400 patients, MoCA and MMSE scores were significantly correlated (all P<0.001) with WMH volumes (rMoCA=-0.336; rMMSE=-0.297) and FA (rMoCA=0.409; rMMSE=0.369) and-on voxel-wise analyses-with WMH in frontal white matter and reduced FA in almost all white matter tracts. However, only the MoCA was independently correlated with WMH volumes (r=-0.183; P<0.001), average FA values (r=0.218; P<0.001), and voxel-wise reduced FA in anterior tracts after controlling for the MMSE. In addition, patients with low MoCA but normal MMSE (n=57) had higher WMH volumes (t=3.1; P=0.002), lower average FA (t=-4.0; P<0.001), and lower voxel-wise FA in almost all white matter tracts than those with normal MoCA and MMSE (n=238). CONCLUSIONS: In patients with transient ischemic attack or minor stroke, early cognitive impairment detected with the MoCA but not with the MMSE was independently associated with white matter damage on magnetic resonance imaging, particularly reduced FA.

Assessment of Blood-Brain Barrier Permeability by Dynamic Contrast-Enhanced MRI in Transient Middle Cerebral Artery Occlusion Model after Localized Brain Cooling in Rats.

OBJECTIVE: The purpose of this study was to evaluate the effects of localized brain cooling on blood-brain barrier (BBB) permeability following transient middle cerebral artery occlusion (tMCAO) in rats, by using dynamic contrast-enhanced (DCE)-MRI. MATERIALS AND METHODS: Thirty rats were divided into 3 groups of 10 rats each: control group, localized cold-saline (20℃) infusion group, and localized warm-saline (37℃) infusion group. The left middle cerebral artery (MCA) was occluded for 1 hour in anesthetized rats, followed by 3 hours of reperfusion. In the localized saline infusion group, 6 mL of cold or warm saline was infused through the hollow filament for 10 minutes after MCA occlusion. DCE-MRI investigations were performed after 3 hours and 24 hours of reperfusion. Pharmacokinetic parameters of the extended Tofts-Kety model were calculated for each DCE-MRI. In addition, rotarod testing was performed before tMCAO, and on days 1-9 after tMCAO. Myeloperoxidase (MPO) immunohisto-chemistry was performed to identify infiltrating neutrophils associated with the inflammatory response in the rat brain. RESULTS: Permeability parameters showed no statistical significance between cold and warm saline infusion groups after 3-hour reperfusion 0.09 ± 0.01 min(-1) vs. 0.07 ± 0.02 min(-1), p = 0.661 for K(trans); 0.30 ± 0.05 min(-1) vs. 0.37 ± 0.11 min(-1), p = 0.394 for kep, respectively. Behavioral testing revealed no significant difference among the three groups. However, the percentage of MPO-positive cells in the cold-saline group was significantly lower than those in the control and warm-saline groups (p < 0.05). CONCLUSION: Localized brain cooling (20℃) does not confer a benefit to inhibit the increase in BBB permeability that follows transient cerebral ischemia and reperfusion in an animal model, as compared with localized warm-saline (37℃) infusion group.

The High Frequency of Guideline-Approved and Guideline-Disapproved Medication Use in Stroke and Transient Ischemic Attack.

BACKGROUND AND PURPOSE: Administration of evidence-based pharmacotherapy improves stroke outcome while the use of non-evidence-based medications may not be of benefit and leads to unnecessary patient care costs. The aim of our study was to determine the frequency of guideline-approved and guideline-disapproved pharmacotherapy use in acute stroke management in the Czech Republic (CR). METHODS: Using the ICD-10 codes, 500 stroke and transient ischemic attack (TIA) patients were randomly selected (random selection of 10 hospitals and then 50 patients from each hospital) from the National Registry of Hospitalized Patients for strokes occurring in 2011. Discharge summaries were reviewed for medications prescribed during hospitalization and at discharge. RESULTS: Of the 500 requested discharge summaries, 484 were available for review (response rate 97%). Up to 479 (96%) summaries were sufficient for evaluation and of these, 393 were confirmed to have a stroke or TIA diagnosis. Brain imaging (computed tomography or magnetic resonance imaging) was performed in 97% of the 393 cases. Intravenous thrombolysis was administered to 7% of patients with ischemic stroke (rate was 0%-25% in different hospitals). Up to 97% of patients with ischemic events (TIA or ischemic stroke) were treated with antiplatelets or anticoagulants. At least 1 non-evidence-based medication was administered to 28% of the 393 patients (rate was 5%-89% in different hospitals). CONCLUSIONS: Guideline-disapproved pharmacotherapy is common in stroke and TIA patients in the CR and processes should be put into place to lessen the frequency of their use. The use of guideline-approved medications is also high and should be further promoted.

Assessment of morphology of patent foramen ovale with transesophageal echocardiography in symptomatic and asymptomatic patients.

BACKGROUND: The frequency of patent foramen ovale (PFO) is greater in patients who have had a stroke and transient ischemic attack (TIA) than that in the general population. However, it is not well defined, which PFO would cause stroke or TIA. In this trial, we aimed to evaluate whether there was a difference regarding morphologic features of PFO in patients who were symptomatic (cryptogenic stroke or history of TIA) or asymptomatic according to the neurologic findings. METHODS: Symptomatic patients with PFO and cryptogenic stroke or TIA and asymptomatic patients with PFO who were symptomatic in terms of neurologic findings as well as patients without any neurologic symptoms in whom PFO was diagnosed incidentally by transesophageal echocardiography were enrolled to this retrospective study on the condition that they were aged younger than 55 years. Not only the clinical and demographic characteristics of 2 groups were compared but also their morphological features were assessed. The morphologic features of PFO that were assessed included the length and height of tunnel, atrial septal excursion distance, thickness of septum primum, and thickness of septum secundum. RESULTS: One hundred fifty-six patients, 64 of whom were symptomatic, were enrolled to this study. The height of PFO (median, 3.0 [interquartile range, 2.0-3.8]mm versus 2.0 [2.0-2.0]mm, P < .001), thickness of septum secundum (5.0 [5.0-7.0] versus 3.0 [2.0-3.0], P < .001), and septal excursion distance (7.0 [6.0-10.5] versus 4.0 [4.0-5.0], P < .001) were found to be greater in the symptomatic group than those in the asymptomatic group. There was no significant difference regarding the length of tunnel and thickness of septum primum. The ratio of length to height of PFO tunnel was less in the symptomatic group (3.0 [3.0-3.23] versus 5.0 [4.0-6.25], P < .001). CONCLUSIONS: Our findings appear to indicate that a higher PFO tunnel, relatively greater interatrial septal mobility, thicker septum pellucidum, and the presence of an atrial septal aneurysm may help identifying the subjects at the age of or younger than 55 years with PFO who are at greater risk for cryptogenic stroke or TIA.

Yield of ultra-rapid carotid ultrasound and stroke specialist assessment in patients with TIA and minor stroke: an Italian TIA service audit.

In Italy the vast majority of TIA and minor strokes are seen in the A&E. Early diagnosis and management of TIA and minor stroke in this setting is habitually difficult and often lead to cost-ineffective hospital admissions. We set up an ultra-rapid TIA service run by neurovascular physicians based on early specialist assessment and ultrasound vascular imaging. We audit the clinical effectiveness and feasibility of the service and the impact of this service on TIA and minor strokes hospital admissions. We compared the rate of TIA and minor stroke admissions/discharges in the year before (T0) and in the year during which the TIA service was operating (T1). At T1 57 patients had specialist evaluation and 51 (89.5 %) of them were discharged home. Two (3.5 %) patients had recurrent symptoms after discharge. Seven had a pathological carotid Doppler ultrasound. Four of them had hospital admission and subsequent carotid endoarterectomy within a week. Taking the whole neurology department into consideration at T1 there was a 30-41 % reduction in discharges of patients with TIA or minor stroke. Taking the stroke unit section into consideration at T1 there was a 25 % reduction in admissions of patients with NIHSS score <4 and 40 % reduction in admissions of patients with Barthel Index above 80. The model of TIA service we implemented based on ultra-rapid stroke physician assessment and carotid ultrasound investigation is feasible and clinically valid. Indirect evidence suggests that it reduced the rate of expensive TIA/minor stroke hospital admissions.

Current concepts on magnetic resonance imaging (MRI) perfusion-diffusion assessment in acute ischaemic stroke: a review & an update for the clinicians.

Recently, several medical societies published joint statements about imaging recommendations for acute stroke and transient ischaemic attack patients. In following with these published guidelines, we considered it appropriate to present a brief, practical and updated review of the most relevant concepts on the MRI assessment of acute stroke. Basic principles of the clinical interpretation of diffusion, perfusion, and MRI angiography (as part of a global MRI protocol) are discussed with accompanying images for each sequence. Brief comments on incidence and differential diagnosis are also included, together with limitations of the techniques and levels of evidence. The purpose of this article is to present knowledge that can be applied in day-to-day clinical practice in specialized stroke units or emergency rooms to attend patients with acute ischaemic stroke or transient ischaemic attack according to international standards.

Transient ischemic dilation ratio in 82Rb PET myocardial perfusion imaging: normal values and significance as a diagnostic and prognostic marker.

UNLABELLED: In myocardial perfusion SPECT, transient ischemic dilation ratio (TID) is a well-established marker of severe ischemia and adverse outcome. However, its role in the setting of (82)Rb PET is less well defined. METHODS: We analyzed 265 subjects who underwent clinical rest-dipyridamole (82)Rb PET/CT. Sixty-two subjects without a prior history of cardiac disease and with a normal myocardial perfusion study had either a low or a very low pretest likelihood of coronary artery disease or negative CT angiography. These subjects were used to establish a reference range of TID. In the remaining 203 patients with an intermediate or high pretest likelihood, subgroups with normal and abnormal TID were established and compared with respect to clinical variables, perfusion defect scores, left ventricular function, and absolute myocardial flow reserve. Follow-up was obtained for 969 ± 328 d to determine mortality by review of the social security death index. RESULTS: In the reference group, TID ratio was 0.98 ± 0.06. Accordingly, a threshold for abnormal TID was set at greater than 1.13 (0.98 + 2.5 SDs). In the study group, 19 of 203 patients (9%) had an elevated TID ratio. Significant differences between subgroups with normal and abnormal TID ratio were observed for ejection fraction reserve (5.0 ± 6.4 vs. 1.8 ± 7.9; P < 0.05), difference between end-systolic volume (ESV) at rest and stress (ΔESV[stress-rest]; 1.8 ± 7.4 vs. 12.3 ± 13.0 mL; P < 0.0001), difference between end-diastolic volume (EDV) at rest and stress (ΔEDV[stress-rest]; 10.8 ± 11.5 vs. 23.8 ± 14.6 mL; P < 0.0001), summed rest score (1.8 ± 3.8 vs. 3.8 ± 7.6; P < 0.05), summed stress score (3.0 ± 5.4 vs. 7.5 ± 9.8; P < 0.002), summed difference score (1.3 ± 2.6 vs. 3.7 ± 5.3; P < 0.02), and global myocardial flow reserve (2.1 ± 0.8 vs. 1.7 ± 0.6; P < 0.02). Additionally, TID-positive patients had a significantly lower overall survival probability (P < 0.05). In a subgroup analysis of patients without regional perfusion abnormalities, TID-positive patients' overall survival probability was significantly smaller (P < 0.03), and TID was an independent predictor (exponentiation of the B coefficients [Exp(b)] = 6.22; P < 0.009) together with an ejection fraction below 45% (Exp[b] = 6.16; P < 0.002). CONCLUSION: The present study suggests a reference range of TID for (82)Rb PET myocardial perfusion imaging that is in the range of previously established values for SPECT. Abnormal TID in (82)Rb PET is associated with more extensive left ventricular dysfunction, ischemic compromise, and reduced global flow reserve. Preliminary outcome analysis suggests that TID-positive subjects have a lower overall survival probability.

Assessment of carotid plaque stability based on the dynamic enhancement pattern in plaque components with multidetector CT angiography.

BACKGROUND AND PURPOSE: Recent studies have investigated plaque morphology to determine patients who are at high risk of carotid atherosclerosis. In this study, we investigated whether a difference in dynamic enhancement pattern in plaque components could be useful to assess plaque stability with multidetector CT angiography. METHODS: Fifty-nine lesions with moderate to severe carotid atherosclerosis in 51 patients (33 symptomatic, 18 asymptomatic) were consecutively included. Early- and delayed-phase images were obtained in 3 equivalent axial slices with multidetector CT angiography. Hounsfield units (HU) in the early phase were subtracted from those in the delayed phase in plaques (ΔHU) and compared with clinical features, MRI-based plaque characteristics, and histological findings with 20 surgical specimens acquired from carotid endarterectomy. RESULTS: The ΔHU was significantly higher in asymptomatic than that in symptomatic presentation (P=0.02). With MRI, a higher ΔHU was negatively correlated with signal intensity on T1-weighted imaging (r=-0.56, P<0.0001). Histology confirmed that ΔHU was positively correlated with fibrous tissue (r=0.67, P=0.001) and negatively correlated with a lipid-rich necrotic core with hemorrhage (r=-0.70, P<0.001). Moreover, less neovascularization and inflammation was found in plaques with a higher ΔHU. CONCLUSIONS: Delayed-phase images provide information regarding the dynamic change in contrast media from the early arterial phase. An increase in HU from the early phase on multidetector CT angiography indicates plaque stability with more fibrous tissue and a less lipid-rich necrotic core, intraplaque hemorrhage, and neovascularization.

Hemodynamic assessment of cervical internal carotid artery stenosis during head manipulation: case report.

Positional intermittent carotid ischemia has rarely been reported in the literature. We report a case of fluctuating hemiparesis in a 88-year-old woman in whom transcranial Doppler ultrasonography at various head positions proved useful in establishing the mechanism of the hypoperfusion transient ischemic attack. Head rotation to the side of the stenotic internal carotid artery resulted in significant drop in ipsilateral middle cerebral artery mean flow velocity.