Derek Emery

Vertebral artery dissection: Warning symptoms, clinical features and prognosis in 26 patients

BACKGROUND AND OBJECTIVES Internal carotid artery dissection has been extensively studied and well-described. Although there has been a recent increase in the number of reported cases of vertebral artery (VA) dissection, the clinical variety of presentation and the early warning symptoms have not been well-described before. Our objectives in this study include: (1) To determine the early symptoms and warning signs which may help the clinician in the early identification and treatment of patients with VA dissection. (2) To explore the variety of clinical presentation of VA dissection and its relation to prognosis. DESIGN AND SETTING Retrospective analysis of hospital records in a tertiary academic centre for the period 1989-1999. RESULTS Twenty-six patients were identified (13 men and 13 women). The mean age was 48. Possible precipitating factors were identified in 14 patients (53%). Sporting activity and chiropractic manipulations were the most common (15% and 11% respectively). Headache and/or neck pain was the prominent feature in 88% of patients and was a warning sign in 53%, preceding onset of stroke by up to 14 days. The most common clinical features included vertigo (57%), unilateral facial paresthesia (46%), cerebellar signs (33%), lateral medullary signs (26%) and visual field defects (15%). Bilateral VA dissection presented in six patients (24%). The most common region of dissection was the C1-C2 level (16 arteries, 51%). Intracranial VA dissection was found in eight arteries (25%). The majority of patients (83%) had favorable outcome. Poor prognosis was associated with (1) bilateral dissection; (2) intracranial VA dissection accompanied by subarachnoid hemorrhage. Only two patients reported stroke recurrence. CONCLUSIONS Our findings show that VA dissection affects mainly middle age persons and involves both sexes equally. Headache and/or neck pain followed by vertigo or unilateral facial paresthesia is an important warning sign that may precede onset of stroke by several days. Although the majority of patients will have excellent prognosis, this was less likely in patients presenting with subarachnoid hemorrhage or bilateral VA dissection. Recurrence rate was low.

Short-term, long-term and paracrine effect of human umbilical cord-derived stem cells in lung injury prevention and repair in experimental bronchopulmonary dysplasia

Background Bronchopulmonary dysplasia (BPD) remains a main complication of extreme prematurity and currently lacks efficient treatment. Rat bone marrow-derived mesenchymal stem cells (MSC) prevent lung injury in an oxygen-induced model of BPD. Human cord is an advantageous source of stem cells that is especially appealing for the treatment of neonatal diseases. The therapeutic benefit after established lung injury and long-term safety of cord-derived stem cells is unknown. Methods Human cord-derived perivascular cells (PCs) or cord blood-derived MSCs were delivered prophylactically or after established alveolar injury into the airways of newborn rats exposed to hyperoxia, a well-established BPD model. Results Rat pups exposed to hyperoxia showed the characteristic arrest in alveolar growth with air space enlargement and loss of lung capillaries. PCs and MSCs partially prevented and rescued lung function and structure. Despite therapeutic benefit, cell engraftment was low, suggesting that PCs and MSCs act via a paracrine effect. Accordingly, cell free-derived conditioned media from PCs and MSCs also exerted therapeutic benefit when used either prophylactically or therapeutically. Finally, long-term (6 months) assessment of stem cell or conditioned media therapy showed no adverse lung effects of either strategy, with persistent improvement in exercise capacity and lung structure. Conclusions Human umbilical cord-derived PCs and MSCs exert short- and long-term therapeutic benefit without adverse lung effects in this experimental model and offer new therapeutic options for lung diseases characterised by alveolar damage.

Vessel contrast at three Tesla in time-of-flight magnetic resonance angiography of the intracranial and carotid arteries

The effects of the increased field strength of 3T on blood vessel contrast in three-dimensional time-of-flight (TOF) MR angiography (MRA) of the intracranial and carotid arteries was evaluated. Bloch equation simulations based on measured longitudinal relaxation times suggested superior blood-to-background contrast might be expected at 3T over 1.5T when using typical 3D TOF MRA parameters. A 15-volunteer study found that 3T was preferable over 1.5T for visualising distal intracranial vessels and the carotid arteries, by providing superior background suppression and excellent fat suppression. The combination of improved background suppression and improved signal-to-noise at 3T, enabled high resolution intracranial 3D TOF MRA with voxel volumes as small as 0.14 mm(3) to be acquired.

Age and dementia-associated atrophy predominates in the hippocampal head and amygdala in Parkinson's disease.

The hippocampus (HC) and amygdala (AG) decrease in volume with age and in Parkinsons disease (PD) with (PDD) and without dementia. We compared 44 PD to 44 age, sex and education-matched subjects without PD (non-PD) and 13 PDD subjects. T1-weighted MR images were used to manually segment the head, body and tail of the HC and the AG. HC volumes, corrected to intracranial volume, were smaller in PDD than non-PD (p=0.04), reflected predominantly by head atrophy. Right AG volumes were smaller in PD compared to non-PD (p=0.03). HC volumes in older (>70), but not younger, non-demented PD differed from non-PD (HC, p=0.02; head, p=0.03). Age correlated negatively with overall HC (r=-0.43, p=0.004) and head (r=-0.48, p=0.001) in PD, but not in non-PD. In PD, left HC head volumes correlated with recall, but not recognition scores on the CVLT-II (r=0.35, p=0.02) and BVMT-R (r=0.35, p=0.02); AG volumes correlated with CVLT-II recall (r=0.35, p=0.02). No correlations were found in non-PD (p>0.4). In conclusion, functionally meaningful age-associated hippocampal and amygdala atrophy occurs in PD.

Voxel-based morphometry reveals extra-nigral atrophy patterns associated with dopamine refractory cognitive and motor impairment in parkinsonism

OBJECTIVES To determine overall patterns of brain atrophy associated with memory, executive function (EF) and dopamine non-responsive motor measures in older parkinsonian patients. DESIGN Forty-three older PD patients (>or=65 years) and matched controls underwent a neurological examination (Unified Parkinsons Disease Rating Scale, separated into dopamine responsive and dopamine non-responsive signs) and neuropsychological testing (memory: California Verbal Learning Test (CVLT)) and a composite of index of executive function (EF): Stroop Interference, Trail Making Test Part B, and digit ordering. All underwent volumetric MRI scans analyzed using voxel-based morphometry (VBM). Group comparisons, and the correlations between MRI gray and white matter volume and motor and cognitive measures were controlled for age, sex and intracranial volume. Cerebellar volume was independently measured using a validated extraction method. RESULTS Patients and controls were matched for demographics and global cognitive measures. VBM indicated significant gray matter (GM) atrophy in the cerebellum in PD and was confirmed independently. Poor memory was associated with GM atrophy in the left (uncus, middle temporal and fusiform gyri) and right temporal lobes and left putamen. Dopamine non-responsive motor signs and EF were associated with caudate atrophy. EF was also associated with GM atrophy in the middle temporal gyri, the left precuneus and cerebellum. CONCLUSIONS Cortical and striatal atrophy were associated with dopamine non-responsive motor signs and cognitive impairment and provide a morphologic correlate for progression of PD. Cerebellar atrophy was found in older PD patients.

Determining epidural catheter location using nerve stimulation with radiological confirmation

BACKGROUND AND OBJECTIVES The use of epidural stimulation to confirm epidural catheter placement has been shown. This case report describes the benefits and problems of using the epidural stimulation test to confirm epidural catheter placement and provides supporting evidence for these observations using radiological imaging. CASE REPORT METHODS A nerve stimulator was connected to the proximal end of an epidural catheter via an adapter. The cathode lead was connected to the adapter. The anode lead was connected to an electrode placed on the upper extremity as a grounding site. Using 1 to 10 mA current, a segmental motor response indicated that the catheter was in the epidural space. The absence of a motor response indicated that it was not. CASES In the first patient, the new test predicted subcutaneous epidural catheter placement, which was subsequently confirmed radiologically. In the second patient, the catheter tip was found to be lying near a nerve root, which was again confirmed radiologically. In the third case, a negative test was initially observed with only local muscle movement over the biceps area (T2). After relocation of the grounding electrode to the lower extremity, segmental intercostal muscle movement (T4-5 level) was observed. The catheter placement was radiologically shown to be in the T4-5 region. CONCLUSION This report illustrates some of the potential benefits and problems of using the nerve stimulation test to confirm epidural catheter placement, with radiological verification.

Posterior cingulate metabolic changes occur in Parkinson's disease patients without dementia

The basis for cognitive deficits in Parkinsons disease (PD) is unknown. Hippocampal atrophy has been shown in Alzheimers disease (AD) and PD. N-Acetyl aspartate (NAA)/creatine (Cr) ratio in the posterior cingulate gyrus (PCG) is decreased in AD, but unknown in PD. Volumetric magnetic resonance (MR) imaging (at 1.5 T) determined corrected HC volume and MR spectroscopy (MRS) PCG metabolites in 12 non-demented mild to moderately affected PD patients (six male, six female) and ten controls (five male, five female). Age (PD=60.6 years, control=62.2; P=0.62), education (PD=14.1 years, controls=13.8; P=0.89) and global cognition (Mini-Mental State Exam score: PD=28.7, controls=29.6; P=0.14) did not differ. Only recall (CVLT-II, P=0.046) and NAA/Cr (PD=1.53, controls=1.78; P=0.03) were decreased in PD. Memory correlated with NAA/Cr (r=0.65, P=0.02) in PD. In conclusion, cingulate metabolic changes occur in PD.

Multiple Sclerosis: Validation of MR Imaging for Quantification and Detection of Iron

PURPOSE To investigate the relationship between iron staining and magnetic resonance (MR) imaging measurements in postmortem subjects with multiple sclerosis (MS). MATERIALS AND METHODS Institutional ethical approval was obtained, and informed consent was obtained from the subjects and/or their families. Four MR imaging methods based on transverse relaxation (T2 weighting, R2 mapping, and R2* mapping) and phase imaging were performed by using a 4.7-T system in three in situ postmortem patients with MS less than 28 hours after death and in one in vivo patient 1 year before death. Iron staining with the Perls iron reaction was performed after brain extraction. Region-of-interest measurements from six subcortical gray matter structures were obtained from MR imaging and then correlated with corresponding locations on photographs of iron-stained pathologic slices by using a separate linear least-squares regression in each subject. Iron status of white matter lesions, as determined by staining, was compared with appearance on MR images. RESULTS R2* mapping had the highest intrasubject correlations with iron in subcortical gray matter (R(2) = 0.857, 0.628, and 0.685; all P < .001), while R2 mapping (R(2) = 0.807, 0.615, 0.628, and 0.489; P < .001 and P = .001, .034, and .001, respectively), phase imaging (R(2) = 0.672, 0.441, 0.596, 0.548; all P ≤ .001), and T2-weighted imaging (R(2) = 0.463, 0.582, 0.650, and 0.551; all P < .001) had lower but still strong correlations. Within lesions, hypointense areas on phase images did not always represent iron. A hyperintense rim surrounding lesions on R2* maps was only present with iron staining, yet not all iron-staining lesions had R2* rim hyperintensity. CONCLUSION All four MR imaging methods had significant linear correlations with iron and could potentially be used to determine iron status of subcortical gray matter structures in MS, with R2* mapping being preferred. A reliable method of determining iron status within MS lesions was not established.

Intravenous rt-PA for acute stroke: comparing its effectiveness in younger and older patients

Objective: To study the short and long term differences in outcome between patients ⩾80 years of age and those ⩽79 years of age who received intravenous recombinant tissue plasminogen activator (iv rt-PA) for acute stroke within the first 3 hours of symptom onset. Methods: We studied consecutive patients treated with iv rt-PA for acute stroke, with prospective follow up of up to 3 years. Outcome measures included National Institutes of Health Stroke Scale (NIHSS) score, Barthel Index (BI), modified Rankin score (MRS), and stroke mortality. Patients were split into two groups: younger (⩽79 years) and older (⩾80 years). Results: There were 65 patients in the younger cohort and 31 patients in the older. Older patients were more likely to present with more severe baseline stroke (p = 0.04; odds ratio (OR) 3.04; 95% confidence interval (CI) 1.03 to 8.98). Stroke mortality at 90 days was 10.8% in the younger and 32.3% in the older cohort (p = 0.01). At 90 days’ follow up, patients in the older cohort with more severe stroke (NIHSS score ⩾11) were nearly 10 times more likely to have poor outcome compared with their younger counterparts presenting with severe stroke (p = 0.001; OR = 10.36; 95% CI 2.16 to 49.20). Baseline stroke severity and age were the only independent and equal predictors for stroke outcome. No threshold was found for age or baseline stroke severity predicting outcome. Conclusion: Older patients presenting with more severe baseline stroke are much less likely to benefit from iv rt-PA as compared with their younger counterparts.

Detection of subdural placement of epidural catheter using nerve stimulation

Purpose: To report the detection of a subdural catheter placement using nerve stimulation through an epidural catheter.Clinical features: An 85-yr-old gentleman was scheduled for radical cystectomy and creation of an ileal conduit. Combined general anesthesia and regional technique was selected. An epidural catheter (19 G Arrow Flextip Plus) was inserted prior to induction of general anesthesia. Intra-operatively, the patient received 5 mg morphine and 10 ml bupivacane 0.5% via the epidural catheter. The patient remained hemodynamically stable throughout the operation and did not require intravenous opioids. The patient was discharged to the ward with an order for epidural morphine for pain control. The next day, the patient remained comfortable. As an ongoing quality assessment to survey the success rate of epidural catheters at our institution, all patients are invited to have their catheter assessed using an electrical epidural stimulation test. Electrical stimulation (1–10mA) with a segmental motor response (truncal or extremities movement) indicates that the catheter is in the epidural space. No motor response indicates that it is not. In this case, subdural catheter placement was suspected because a diffuse motor response including right anterior chest wall, back muscle, and bilateral lower extremities was observed using only 0.3 mA. Subdural catheter placement was subsequently confirmed by a radiograph showing a very thin film of dye spreading cephalad and caudad over many segments.Conclusion: This new electrical test helps to detect subdural placement objectively.RésuméObjectif: Rapporter la détection du positionnement d’un cathéter sous-dural à l’aide de la neurostimulation au travers d’un cathéter péridural.Éléments cliniques: Une cystectomie radicale avec création d’un canal iléal a été prévue chez un homme de 85 ans. On a choisi une anesthésie générale combinée à une technique régionale. Un cathéter péridural (19 G Arrow Flextip Plus) a été inséré avant l’induction de l’anesthésie générale. Pendant l’opération, le patient a reçu 5 mg de morphine et 10 ml de bupivacaïne à 0,5 % au travers du cathéter péridural. La stabilité hémodynamique s’est maintenue pendant l’intervention et le patient n’a pas eu besoin d’opioïdes intraveineux. Le patient a quitté le service avec une prescription de morphine péridurale contre la douleur. Le jour suivant, il se portait toujours bien. Afin d’étudier le taux de réussite de l’usage de cathéters périduraux à notre institution, nous procédons à une analyse permanente de la qualité, invitant les patients à faire évaluer leur cathéter au moyen de test de neurostimulation. La stimulation électrique (1–10 mA), par une réponse motrice segmentaire (mouvement du tronc ou des extrémités), indique si le cathéter est dans l’espace péridural. L’absence de réponse motrice indique qu’il ne l’est pas. Dans le cas présent, un positionnement sous-dural du cathéter est envisagé parce qu’une réponse motrice diffuse, incluant la paroi thoracique antérieure droite, les muscles du dos et les extrémités inférieures bilatérales, a été observée en utilisant un courant de seulement 0,3 mA. La position sous-durale a été confirmée par une radiographie ultérieure montrant une très mince couche de colorant qui s’étendait en direction céphalique et caudale sur de nombreux segments.Conclusion: Ce nouveau test électrique aide à détecter objectivement le placement sous-dural d’un cathéter.