Inger Havsteen

Prevalence and long-term clinical significance of intracranial atherosclerosis after ischaemic stroke or transient ischaemic attack: a cohort study

Objectives We investigated the prevalence and long-term risk associated with intracranial atherosclerosis identified during routine evaluation. Design This study presents data from a prospective cohort of patients admitted to our stroke unit for thrombolysis evaluation. Setting and participants We included 652 with a final diagnosis of ischaemic stroke or transient ischaemic attack (TIA) from April 2009 to December 2011. All patients were acutely evaluated with cerebral CT and CT angiography (CTA). Acute radiological examinations were screened for intracranial arterial stenosis (IAS) or intracranial arterial calcifications (IAC). Intracranial stenosis was grouped into 30–50%, 50–70% and >70% lumen reduction. The extent of IAC was graded as number of vessels affected. Primary and secondary outcome measure Patients were followed until July 2013. Recurrence of an ischaemic event (stroke, ischaemic heart disease (IHD) and TIA) was documented through the national chart system. Poor outcome was defined as death or recurrence of ischaemic event. Results 101 (15.5%) patients showed IAS (70: 30–50%, 29: 50–70% and 16: >70%). Two-hundred and fifteen (33%) patients had no IAC, 339 (52%) in 1–2 vessels and 102 (16%) in >2 vessels. During follow-up, 53 strokes, 20 TIA and 14 IHD occurred, and 95 patients died. The risk of poor outcome was significantly different among different extents of IAS as well as IAC (log-rank test p<0.01 for both). In unadjusted analysis IAS and IAC predicted poor outcome and recurrent ischaemic event. When adjusted, IAS and IAC independently increased the risk of a recurrent ischaemic event (IAS: HR 1.67; CI 1.04 to 2.64 and IAC: HR 1.22; CI 1.02 to 1.47). Conclusions Intracranial atherosclerosis detected during acute evaluation predicts an increased risk of recurrent stroke.

Time Course of Early Postadmission Hematoma Expansion in Spontaneous Intracerebral Hemorrhage

Background and Purpose— Early hematoma expansion (EHE) in patients with intracerebral hematoma is a promising treatment target. To date, the time course of EHE has remained poorly described. We prospectively investigated the time course of EHE. Methods— We included consecutive patients presenting spontaneous intracerebral hematoma within 4.5 hours. On admission, patients underwent noncontrast computed tomography (CT) and CT angiography. Serial hematoma volume estimations by transcranial B-mode ultrasound were effected through the contralateral transtemporal bone window by obtaining sagittal, transversal, and coronal diameter and calculating the ABC/2-formula. National Institute of Health Stroke Scale and transcranial B-mode ultrasound were performed consecutively every 30 minutes during the first 6 hours and from 6 to 12 hours every 2 hours. Follow-up CT and ultrasound were performed after ≈24 hours. Results— Twenty-five patients with intracerebral hematoma were included; mean (SD) time from onset to CT was 108.6 (45.7) minutes. Ten (40%) patients had EHE. In patients with a final clinically significant hematoma expansion >12.5 mL, all EHE occurred within 6 hours after admission scan. EHE in spot sign positive patients continued during the first 5 hours after CT angiography. In spot sign–negative patients, no significant EHE was observed (Friedman test, P=0.476). Neurological deterioration occurred in 5 (20%) patients and was well temporally correlated with EHE. Transcranial B-mode ultrasound demonstrated good volume estimation compared with the follow-up CT with a maximum absolute volume deviation within 7 mL and minimal systematic error (mean deviation, 1.3 [confidence interval, −0.1 to 2.6] mL). Conclusions— EHE was reliably reflected by transcranial B-mode ultrasound and mainly occurred within the first 7 to 8 hours after symptom onset. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01472224.

Prediction and observation of post-admission hematoma expansion in patients with intracerebral hemorrhage.

Post-admission hematoma expansion in patients with intracerebral hemorrhage (ICH) comprises a simultaneous major clinical problem and a possible target for medical intervention. In any case, the ability to predict and observe hematoma expansion is of great clinical importance. We review radiological concepts in predicting and observing post-admission hematoma expansion. Hematoma expansion can be observed within the first 24 h after symptom onset, but predominantly occurs in the early hours. Thus capturing markers of on-going bleeding on imaging techniques could predict hematoma expansion. The spot sign observed on computed tomography angiography is believed to represent on-going bleeding and is to date the most well investigated and reliable radiological predictor of hematoma expansion as well as functional outcome and mortality. On non-contrast CT, the presence of foci of hypoattenuation within the hematoma along with the hematoma-size is reported to be predictive of hematoma expansion and outcome. Because patients tend to arrive earlier to the hospital, a larger fraction of acute ICH-patients must be expected to undergo hematoma expansion. This renders observation and radiological follow-up investigations increasingly relevant. Transcranial duplex sonography has in recent years proven to be able to estimate hematoma volume with good precision and could be a valuable tool in bedside serial observation of acute ICH-patients. Future studies will elucidate, if better prediction and observation of post-admission hematoma expansion can help select patients, who will benefit from hemostatic treatment.

Showing no spot sign is a strong predictor of independent living after intracerebral haemorrhage.

Background: A spot sign on computed tomography angiography (CTA) is a potentially strong predictor of poor outcome on ultra-early radiological imaging. The aim of this study was to assess the spot sign as a predictor of functional outcome at 3 months as well as long-term mortality, with a focus on the ability to identify patients with a spontaneous, acceptable outcome. Methods: In a prospective, consecutive single-centre registry of acute stroke patients, we investigated patients with spontaneous intracerebral haemorrhage (ICH) admitted within 4.5 h after symptom onset from April 2009 to January 2013. The standard work-up in our centre included CTA for spot sign status, unless a contraindication was present. Modified Rankin Scale (mRS) scores were assessed at 3 months in the outpatient clinic or by telephone interviews. Long-term mortality was assessed by electronic chart follow-up for up to 1,500 days. Results: Of the 128 patients, 37 (28.9%) had a spot sign on admission CTA. The presence of a spot sign was associated with larger median admission haematoma volume [38.0 ml (IQR 18.0-78.0) vs. 12.0 ml (5.0-24.0); p < 0.0001] and higher median National Institutes of Health Stroke Scale score [19 (IQR 12-23) vs. 12 (6-16); p < 0.0001]. Three months after stroke, the median functional outcome was considerably better in patients without spot sign [mRS score 3 (IQR 2-4) vs. 6 (4-6); p < 0.0001]. The absence of a spot sign showed a sensitivity and specificity for good outcome (mRS scores 0-2) of 0.91 and 0.36, respectively. The presence of a spot sign was, in multivariate models, an independent inverse predictor of good 3-month outcome (OR 0.17; 95% CI: 0.03-0.88) as well as a prominent independent predictor of poor 3-month outcome (mRS scores 5-6; OR 3.40; 95% CI: 1.10-10.5) and death during follow-up (HR 3.04; 95% CI: 1.45-6.34). Patients with a spot sign surviving the acute phase had long-term survival comparable to patients with no spot sign. Conclusion: The absence or presence of a spot sign is a reliable ultra-early predictor of long-term mortality and functional outcome in patients with spontaneous ICH.

Diagnostic Approach to Functional Recovery: Functional Magnetic Resonance Imaging after Stroke

Stroke remains the most frequent cause of handicap in adult life and according to the WHO the second cause of death in the Western world. In the peracute phase, intravenous thrombolysis and in some cases endovascular therapy may induce early revascularization and hereby improve prognosis. However, only up to 20-25% of patients are eligible to causal treatment. Further, care in a specialized stroke unit improves prognosis in all patients independent of age and stroke severity. Even when it is not possible to prevent tissue loss, the surviving brain areas of functional brain networks have a substantial capacity to reorganize after a focal ischemic (or hemorrhagic) brain lesion. This functional reorganization contributes to functional recovery after stroke. Functional magnetic resonance imaging (fMRI) provides a valuable tool to capture the spatial and temporal activity changes in response to an acute ischemic lesion. Task-related as well as resting-state fMRI have been successfully applied to elucidate post-stroke remodeling of functional brain networks. This includes regional changes in neuronal activation as well as distributed changes in functional brain connectivity. Since fMRI is readily available and does not pose any adverse effects, repeated fMRI measurements provide unprecedented possibilities to prospectively assess the time course of reorganization in functional neural networks after stroke and relate the temporospatial dynamics of reorganization at the systems level to functional recovery. Here we review the current status and future perspectives of fMRI as a means of studying functional brain reorganization after stroke. We summarize (a) how fMRI has advanced our knowledge regarding the recovery mechanisms after stroke, and (b) how fMRI has been applied to document the effects of therapeutical interventions on post-stroke functional reorganization.

Interobserver agreement in fusion status assessment after instrumental desis of the lower lumbar spine using 64-slice multidetector computed tomography: impact of observer experience

PurposePersistent lower back pain after instrumental posterolateral desis may arise from incomplete fusion. We investigate the impact of experience on interobserver agreement in fusion estimation.MethodsFour independent observers, two residents and two musculoskeletal radiologists, reviewed dedicated lumbar 64-MDCT scans and scored vertebral levels 1–5 after Glassman’s grades, 1: solid bilateral fusion, 2: solid unilateral fusion, 3: partial bilateral fusion, 4: partial unilateral fusion, 5: non-fusion. We investigated two simplifying dichotomizations, solid bilateral fusion (Glassman 1) versus all others and uni- or bilateral fusion (Glassman 1–2) versus partial or non-fusion.ResultsThirty-six patients with 61 operated lumbar levels were included. Interobserver agreement rates for four observers using Glassman’s system were fair (kappa 0.32), either dichotomization showed moderate agreement (kappa 0.53 and 0.59). Observer pairs had comparable prevalence adjusted interobserver agreement rates (residents: PABAK 0.67 and 0.54; consultants: PABAK 0.57 and 0.71).ConclusionsDifference in observer experience seems of minor impact.

Are Movement Artifacts in Magnetic Resonance Imaging a Real Problem?—A Narrative Review

Movement artifacts compromise image quality and may interfere with interpretation, especially in magnetic resonance imaging (MRI) applications with low signal-to-noise ratio such as functional MRI or diffusion tensor imaging, and when imaging small lesions. High image resolution has high sensitivity to motion artifacts and often prolongs scan time that again aggravates movement artifacts. During the scan fast imaging techniques and sequences, optimal receiver coils, careful patient positioning, and instruction may minimize movement artifacts. Physiological noise sources are motion from respiration, flow and pulse coupled to cardiac cycles, from the swallowing reflex and small spontaneous head movements. Par example, in resting-state functional MRI spontaneous neuronal activity adds 1–2% of signal change, even under optimal conditions signal contributions from physiological noise remain a considerable fraction hereof. Movement tracking during imaging may allow for prospective correction or postprocessing steps separating signal and noise.

The association between areas of secondary hyperalgesia and volumes of the caudate nuclei and other pain relevant brain structures—A 3-tesla MRI study of healthy men

Introduction Central sensitization plays a pivotal role in maintenance of pain and is believed to be intricately involved in several chronic pain conditions. One clinical manifestation of central sensitization is secondary hyperalgesia. The degree of secondary hyperalgesia presumably reflects individual levels of central sensitization. The objective of this study was to investigate the association between areas of secondary hyperalgesia and volumes of the caudate nuclei and other brain structures involved in pain processing. Materials and methods We recruited 121 healthy male participants; 118 were included in the final analysis. All participants underwent whole brain magnetic resonance imaging (MRI). Prior to MRI, all participants underwent pain testing. Secondary hyperalgesia was induced by brief thermal sensitization. Additionally, we recorded heat pain detection thresholds (HPDT), pain during one minute thermal stimulation (p-TS) and results of the Pain Catastrophizing Scale (PCS) and Hospital Anxiety and Depression score (HADS). Results We found no significant associations between the size of the area of secondary hyperalgesia and the volume of the caudate nuclei or of the following structures: primary somatosensory cortex, anterior and mid cingulate cortex, putamen, nucleus accumbens, globus pallidus, insula and the cerebellum. Likewise, we found no significant associations between the volume of the caudate nuclei and HPDTs, p-TS, PCS and HADS. Conclusions Our findings indicate that the size of the secondary hyperalgesia area is not associated with the volume of brain structures relevant for pain processing, suggesting that the propensity to develop central sensitization, assessed as secondary hyperalgesia, is not correlated to brain structure volume.

Small cortical grey matter lesions show no persistent infarction in transient ischaemic attack? A prospective cohort study

Objectives To find determining factors for persistent infarction signs in patients with transient ischaemic attack (TIA), herein initial diffusion lesion size, visibility on apparent diffusion coefficient (ADC) or fluid-attenuated inversion recovery (FLAIR) and location. Design Prospective cohort study of patients with clinical TIA receiving 3T-MRI within 72 hours of symptom onset and at 8-week follow-up. Setting Clinical workflow in a single tertiary stroke centre between February 2012 and June 2014. Participants 199 candidate patients were recruited, 64 patients were excluded due to non-TIA discharge diagnosis or no 8-week MRI. 122 patients completed the study. Primary outcome measures The primary outcome was visible persistent infarction defined as 8-week FLAIR hyperintensity or atrophy corresponding to the initial diffusion-weighted imaging (DWI) lesion. Results 50 patients showed 84 initial DWI lesions. 29 (35%) DWI lesions did not result in infarction signs on 8-week FLAIR. 26 (90%, P<0.0001) reversing lesions were located in the cortical grey matter (cGM). cGM location (vs any other location) strongly predicted no 8-week infarction sign development (OR 0.02, 95% CI 0.001 to 0.17) or partial lesion area decrease (>30% of initial DWI-area, OR 14.10, 95% CI 3.61 to 54.72), adjusted for FLAIR-visibility, DWI-area, ADC-confirmation and time to scan (TTS) from symptom onset to baseline MRI. Acute FLAIR-visibility was a strong associated factor for persistent infarction signs (OR 33.06, 95% CI 2.94 to 1432.34). For cGM lesions area size was sole associated factor for persistent infarction signs with a 0.31 cm2 (area under the curve (AUC), 0.97) threshold. In eight (16%) DWI-positive patients, all lesions reversed fully. Conclusions 16% of DWI-positive patients and one-third of acute DWI lesions caused no persistent infarction signs, especially small cGM lesions were not followed by development of persistent infarction signs. Late MRI after TIA is likely to be less useful in the clinical setting, and it is dubious if the absence of old vascular lesions can be taken as evidence of no prior ischaemic attacks. Trial registration number NCT01531946; Results.

Arterial spin labeling: a technical overview

Arterial spin labeling (ASL) is a non-invasive magnetic resonance imaging perfusion method based on changes in net-magnetization of blood water. The absence of contrast use and ionizing radiation, renders ASL valuable in hyper-acute settings as a monitoring tool for repeated dynamical measurements during and after intervention, and for patients with known co-morbidities. This text provides a short methodological introduction to ASL and contrasts it with traditional contrast-enhanced perfusion imaging. The review focused on sequence usefulness in the clinical setting of acute cerebral ischemia investigation.