Chronic Migraine: An Update on Diagnosis and Management

Background

Chronic migraine is an under-recognized and under-treated disorder. A greater understanding of the pathophysiology of migraine and transformation to chronic migraine has led to the first targeted treatments for chronic migraine. In this review, we review current approaches to the diagnosis and management of chronic migraine and discuss recent and emerging novel therapies.

Objective

The aim of this study was to provide an update on the diagnosis and management of chronic migraine.

Methods and Material

The PubMed database was searched for relevant articles published on or before October 2020.

Results and Conclusions

Chronic migraine is an under-recognized and under-treated disorder. Prompt diagnosis and appropriate management can lead to a significant improvement in the quality of life with subsequent socioeconomic benefits.

Oxygen challenge magnetic resonance imaging in healthy human volunteers

Oxygen challenge imaging involves transient hyperoxia applied during deoxyhaemoglobin sensitive (T2*-weighted) magnetic resonance imaging and has the potential to detect changes in brain oxygen extraction. In order to develop optimal practical protocols for oxygen challenge imaging, we investigated the influence of oxygen concentration, cerebral blood flow change, pattern of oxygen administration and field strength on T2*-weighted signal. Eight healthy volunteers underwent multi-parametric magnetic resonance imaging including oxygen challenge imaging and arterial spin labelling using two oxygen concentrations (target FiO₂ of 100 and 60%) administered consecutively (two-stage challenge) at both 1.5T and 3T. There was a greater signal increase in grey matter compared to white matter during oxygen challenge (p < 0.002 at 3T, P < 0.0001 at 1.5T) and at FiO₂ = 100% compared to FiO₂ = 60% in grey matter at both field strengths (p < 0.02) and in white matter at 3T only (p = 0.0314). Differences in the magnitude of signal change between 1.5T and 3T did not reach statistical significance. Reduction of T2*-weighted signal to below baseline, after hyperoxia withdrawal, confounded interpretation of two-stage oxygen challenge imaging. Reductions in cerebral blood flow did not obscure the T2*-weighted signal increases. In conclusion, the optimal protocol for further study should utilise target FiO₂ = 100% during a single oxygen challenge. Imaging at both 1.5T and 3T is clinically feasible.

Audit of Literacy of Medical Patients in North Glasgow

Aims

We aimed to assess the scale of the problem of illiteracy among our hospital's general medical in-patients and investigate any influence on literacy from gender, age, socioeconomic status, disease process and number of prescribed medications.

Methods

We employed a shortened version of the previously validated Rapid Estimate of Adult Literacy in Medicine (REALM) tool with medical inpatients at Glasgow Royal Infirmary. We also recorded gender, date of birth and clinical problem. Socioeconomic status was estimated from the patient's postcode using the Scottish Index of Multiple Deprivation (SIMD).

Results

60 patients were invited to participate, however six (10%) declined. We therefore gathered data for 54 patients (54% male) with a mean age of 67 years. The female group had a significantly higher mean age of 73 years versus 62 years in men. The mean SIMD quintile was 3.5 (1 least deprived, 5 most deprived) and the mean number of medications was 7. 55% of our patients had a mean score of<60 which represents low health literacy. There were no significant differences in literacy between men (median score 59) and women (median score 60). Reading ability was not found to be associated with socioeconomic group, diseased body system or number of medications on the drug chart (data not shown).

Conclusions

Low level health literacy is prevalent. Affected individuals may have difficulty understanding patient-orientated health literature, medication instructions, clinic appointment cards and hospital signage.

Metabolic imaging of ischemic stroke: the present and future

Measures of cerebral metabolism may be useful in the selection of patients for reperfusion therapies and as end points in clinical trials. However, there are currently no clinically routine techniques that provide such data directly. We review how imaging modalities in current clinical use may provide surrogate markers of metabolic activity. Promising techniques for metabolic imaging that are currently in the pipeline are reviewed.

Multi-center prediction of hemorrhagic transformation in acute ischemic stroke using permeability imaging features

Permeability images derived from magnetic resonance (MR) perfusion images are sensitive to blood-brain barrier derangement of the brain tissue and have been shown to correlate with subsequent development of hemorrhagic transformation (HT) in acute ischemic stroke. This paper presents a multi-center retrospective study that evaluates the predictive power in terms of HT of six permeability MRI measures including contrast slope (CS), final contrast (FC), maximum peak bolus concentration (MPB), peak bolus area (PB), relative recirculation (rR), and percentage recovery (%R). Dynamic T2*-weighted perfusion MR images were collected from 263 acute ischemic stroke patients from four medical centers. An essential aspect of this study is to exploit a classifier-based framework to automatically identify predictive patterns in the overall intensity distribution of the permeability maps. The model is based on normalized intensity histograms that are used as input features to the predictive model. Linear and nonlinear predictive models are evaluated using a cross-validation to measure generalization power on new patients and a comparative analysis is provided for the different types of parameters. Results demonstrate that perfusion imaging in acute ischemic stroke can predict HT with an average accuracy of more than 85% using a predictive model based on a nonlinear regression model. Results also indicate that the permeability feature based on the percentage of recovery performs significantly better than the other features. This novel model may be used to refine treatment decisions in acute stroke.

Rare neurological diseases: a practical approach to management

Although neurologists are frequently faced with the management of rare diseases, there is little generic guidance for the approach to management. There are complexities with respect to diagnosis, counselling, treatment and monitoring which are idiosyncratic to rare diseases. Here we use a case report as the basis for discussion of the management of rare neurological diseases. We discuss current issues, guidance from regulatory bodies, and offer practical tips for diagnosis, treatment and monitoring, including the use of decision tree analysis. We offer a generic algorithm to aid neurologists when facing rare conditions.

Multivoxel MR spectroscopy in acute ischemic stroke: comparison to the stroke protocol MRI

BACKGROUND AND PURPOSE

Few patients with stroke have been imaged with MR spectroscopy (MRS) within the first few hours after onset. We compared data from current MRI protocols to MRS in subjects with ischemic stroke.

METHODS

MRS was incorporated into the standard clinical MRI stroke protocol for subjects <24 hours after onset. MRI and clinical correlates for the metabolic data from MRS were sought.

RESULTS

One hundred thirty-six MRS voxels from 32 subjects were analyzed. Lactate preceded the appearance of the lesion on diffusion-weighted imaging in some voxels but in others lagged behind it. Current protocols may predict up to 41% of the variance of MRS metabolites. Serum glucose concentration and time to maximum partially predicted the concentration of all major metabolites.

CONCLUSIONS

MRS may be helpful in acute stroke, especially for lactate detection when perfusion-weighted imaging is unavailable. Current MRI protocols do provide surrogate markers for some indices of metabolic activity.

Pilot results of in vivo brain glutathione measurements in stroke patients

Measurement of glutathione concentration for the study of redox status in subjects with neurological disease has been limited to peripheral markers. We recruited 19 subjects with large strokes. Using magnetic resonance spectroscopy we measured brain glutathione concentration in the stroke region and in healthy tissue to calculate a glutathione-ratio. Elevated glutathione-ratio was observed in subacute (<72 hours) subjects without hemorrhagic transformation (mean=1.19, P=0.03, n=6). No trend was seen when all subjects were considered (n=19, 3 to 754 hours, range=0.45 to 1.41). This technique can detect glutathione changes because of disease, and may be valuable in clinical trials of stroke and other neurological diseases.

Crossed cerebellar diaschisis: insights into oxygen challenge MRI

Hyperoxia during T2*-weighted magnetic resonance imaging (oxygen challenge imaging (OCI)) causes T2*-weighted signal change that is dependent on cerebral blood volume (CBV) and oxygen extraction fraction (OEF). Crossed cerebellar diaschisis (CCD), where CBV is reduced but OEF is maintained, may be used to understand the relative contributions of OEF and CBV to OCI results. In subjects with large hemispheric strokes, OCI showed reduced signal change in the contralesional cerebellum (P=0.027, n=12). This was associated with reduced CBV in contralesional cerebellum (P=0.039, n=9). CCD may be a useful model to determine the relative contribution of CBV to signal change measured by OCI.

Hyperintense vessel sign on fluid-attenuated inversion recovery MR imaging is reduced by gadolinium

The HVS on FLAIR imaging is a useful marker of acute ischemic stroke. We investigated whether prior administration of gadolinium-based contrast hindered detection of this sign on images from subjects with acute nonlacunar ischemic stroke <4.5 hours after onset. Both blinded and comparative unblinded analyses showed significantly reduced HVS detection on postcontrast images. We suggest that assessment for this sign should be performed on images acquired prior to contrast administration.

Abstract 97: Multiparametric T2*-Permeability MRI Accurately Predicts Hemorrhagic Transformation: STIR/VISTA Imaging Multicenter Observational Study

Background: Perfusion MRI may be used to reveal permeability changes reflective of blood-brain barrier derangements that predate hemorrhagic transformation (HT) in acute ischemic stroke. We conducted a multicenter observational study to compare and validate these novel T2*-permeability MRI measures as predictors of hemorrhage, deriving a predictive model for use with acute stroke therapies.

Methods: Dynamic T2*-weighted perfusion MRI source images routinely obtained in the setting of acute ischemic stroke were collected from four academic medical centers. Post-processing was used to generate six previously described permeability parameters including contrast slope (CS), final contrast (FC), maximum peak bolus concentration (MPB), peak bolus area (PB), relative recirculation (rR), and %Recovery (%R). Clinical data including baseline demographics, medical history, lab values and treatment details were utilized to develop a predictive model for HT, combined with these novel permeability measures. The multivariate predictive model was evaluated using a 10-fold cross-validation to measure its generalization power on new patients.

Results: Among 263 acute ischemic stroke patients analyzed in this large, multicenter collaborative imaging study, mean age was 69±15 years, 58.2% were women and baseline median NIHSS was 10 (range, 0-40). T2*-MRI sequences were acquired as part of routine imaging evaluation at a median of 214 minutes (range, 33-1440) from symptom onset. Treatments included IV tPA alone in 49%, endovascular recanalization therapies alone in 21.2%, and both in 10.4%. Overall, HT on GRE at 24 hours was observed in 84 (31.9%), including 34 HI1, 30 HI2, 9 PH1 and 11 PH2. More severe baseline NIHSS (r= 0.25, p<0.01) predicted HT at 24 hours. Individual T2*-permeability parameters exhibited positive predictive values (PPV) for HT ranging from 79-82% with negative predictive values (NPV) ranging from 70-78%. An automated predictive model integrating clinical data and all 6 multiparametric permeability measures exhibited PPV of 80% and NPV of 73% for HT at 24 hours.

Conclusions: Permeability indices on dynamic T2*-weighted MRI routinely acquired for perfusion imaging in acute ischemic stroke can accurately predict HT using an automated predictive model. This novel automated predictive model may be used to refine treatment decisions in acute stroke.

Systematic Review of Perfusion Imaging With Computed Tomography and Magnetic Resonance in Acute Ischemic Stroke: Heterogeneity of Acquisition and Postprocessing Parameters

Background and Purpose—

Heterogeneity of acquisition and postprocessing parameters for magnetic resonance– and computed tomography–based perfusion imaging in acute stroke may limit comparisons between studies, but the current degree of heterogeneity in the literature has not been precisely defined.

Methods—

We examined articles published before August 30, 2009 that reported perfusion thresholds, average lesion perfusion values, or correlations of perfusion deficit volumes from acute stroke patients <24 hours postictus. We compared acquisition parameters from published studies with guidance from the Acute Stroke Imaging Research Roadmap 1 . In addition, we assessed the consistency of postprocessing parameters.

Results—

Twenty computed tomography perfusion and 49 perfusion-weighted imaging studies were included from 7152 articles. Although certain parameters were reported frequently, consistently, and in line with the Roadmap proposals, we found substantial heterogeneity in other parameters, and there was considerable variation and underreporting of postprocessing methodology.

Conclusions—

There is substantial scope to increase homogeneity in future studies, eg, through reporting standards.

Abstract 3417: Pixel by Pixel Comparison of CTP-Defined Infarct Core on Concurrent Non-Contrast CT

Introduction Interobserver agreement for the presence of early ischemic changes on non-contrast CT (NCCT) in potential thrombolysis candidates can be poor even among experienced raters. CT perfusion (CTP) may demonstrate infarct core and penumbra according to proposed thresholds but the extent of correlation between CTP defined core and hypodensity on hyperacute NCCT is unclear

Methods A pixel by pixel comparison between NCCT and concurrent CTP obtained <6hrs from symptom onset was performed for patients with symptomatic arterial occlusions. Segmentation was performed using time-averaged CTP raw images to compare core and normal tissue pixels for grey and white matter separately. Core was defined as relative Cerebral Blood Flow (CBF) of <45% of normal tissue. NCCT was co-registered to the baseline frames of the concurrent CTP using a rigid body transformation. Core pixels were extracted from CTP and transposed to NCCT. Hounsfield unit (HU) values in CTP-defined core and normal tissue were quantified for grey and white matter. Receiver operating characteristic (ROC) curve analysis was performed to assess the predictive value of NCCT hypodensity and CTP-defined core.

Results CT and CTP were compared for 33 patients. Mean age was 72 years (SD 12), median NIHSS was 16 (IQR 11-20) and mean time from symptom onset to CTP was 191 minutes (SD 63). Area under the curve (AUC) for prediction of grey and white matter core by NCCT was 0.641 and 0.601 respectively. The most frequently occurring optimum HU cut-points were 29 and 28 for grey and white matter respectively .These cut-points were associated with low overall specificity for detecting core (Median ± IQR= 0.48, 0.32-0.59 and 0.36, 0.26-0.44) but higher sensitivity (Median ±IQR 0.79, 0.62-0.87 and 0.83, 0.73-0.89) for grey and white matter

Conclusion Objectively determined hypodensity on NCCT has low sensitivity and specificity for prediction of ischemic core tissue defined by CT perfusion. Thresholds were similar for both grey and white matter. NCCT scans without established hypodensity may still have irreversibly infarcted pixels which can be detected with CTP. Prospective evaluation of the added value of CTP-defined core on decision making in acute stroke is needed.

T2*-weighted magnetic resonance imaging with hyperoxia in acute ischemic stroke

OBJECTIVE

We describe the first clinical application of transient hyperoxia ("oxygen challenge") during T2*-weighted magnetic resonance imaging (MRI), to detect differences in vascular deoxyhemoglobin between tissue compartments following stroke.

METHODS

Subjects with acute ischemic stroke were scanned with T2*-weighted MRI and oxygen challenge. For regions defined as infarct core (diffusion-weighted imaging lesion) and presumed penumbra (perfusion-diffusion mismatch [threshold = T(max) > or =4 seconds], or regions exhibiting diffusion lesion expansion at day 3), T2*-weighted signal intensity-time curves corresponding to the duration of oxygen challenge were generated. From these, the area under the curve, gradient of incline of the signal increase, time to maximum signal, and percentage signal change after oxygen challenge were measured.

RESULTS

We identified 25 subjects with stroke lesions >1ml. Eighteen subjects with good quality T2*-weighted signal intensity-time curves in the contralateral hemisphere were analyzed. Curves from the diffusion lesion had a smaller area under the curve, percentage signal change, and gradient of incline, and longer time to maximum signal (p < 0.05, n = 17) compared to normal tissue, which consistently showed signal increase during oxygen challenge. Curves in the presumed penumbral regions (n = 8) showed varied morphology, but at hyperacute time points (<8 hours) showed a tendency to greater percentage signal change.

INTERPRETATION

Differences in T2*-weighted signal intensity-time curves during oxygen challenge in brain regions with different pathophysiological states after stroke are likely to reflect differences in deoxyhemoglobin concentration, and therefore differences in metabolic activity. Despite its underlying complexities, this technique offers a possible novel mode of metabolic imaging in acute stroke.

Do iodinated contrast agents impair fibrinolysis in acute stroke? A systematic review

BACKGROUND AND PURPOSE

In vitro and nonhuman in vivo studies demonstrating impaired fibrinolysis of thrombus by thrombolytic agents in the presence of iodinated contrast media (ICM) have prompted concern regarding the clinical use of ICM. A systematic review and meta-analysis were performed to investigate the proportion of patients with acute stroke experiencing recanalization after thrombolytic therapy in whom ICM were administered compared with those in whom they were not.

MATERIALS AND METHODS

Embase and Medline searches identified studies reporting recanalization rates in acute ischemic anterior circulation stroke. Pooled proportions of patients who recanalized were calculated with a random-effects model, and studies involving contrast (CS) were compared with those without (NCS).

RESULTS

Six studies were found in which ICM were administered, and 12 studies, in which they were not. Studies were statistically heterogeneous. Combined pooled proportions and 95% confidence intervals (CI) for recanalization in unselected CS and NCS were 53% (36%-70%) and 61% (52%-71%), respectively. In a subgroup analysis in which only middle cerebral artery occlusions were considered, the pooled proportions in CS (n = 3 studies) and NCS (n = 9 studies) were 66% (95% CI, 49%-82%; I(2), 0%) and 63% (CI, 52%-74%; I(2), 82.5%).

CONCLUSIONS

Recanalization rates were not significantly different in patients who received iodinated contrast agents in clinical studies. A randomized trial to test whether ICM affect recanalization would require a prohibitively large number of subjects.

Brain lesion volume and capacity for consent in stroke trials: potential regulatory barriers to the use of surrogate markers

BACKGROUND AND PURPOSE

European directives and legislation in some countries forbid inclusion of subjects incapable of consent in research if recruitment of patients capable of consent will yield similar results. We compared brain lesion volumes in stroke patients deemed to have capacity to consent with those defined as incapacitated.

METHODS

Data were obtained from 3 trials recruiting patients primarily with cortical stroke syndromes. Patients were recruited within 24 hours of onset and used MRI based selection or outcome criteria. Method of recruitment was recorded with stroke severity, age, and brain lesion volumes on Diffusion Weighted Imaging.

RESULTS

Of the 56 subjects included, 38 (68%) were recruited by assent and 18 (32%) by consent. The assent group had a median lesion volume of 18.35 cubic centimetres (cc) (interquartile range [IQR] 8.27-110.31 cc), compared to 2.79 cc (IQR 1.31-12.33 cc) when patients consented (P=0.0004). Lesions were smaller than 5 cc in 7/38 (18%) in the assent group and 11/18 (61%) in the consent group (P=0.0024). There was good correlation between neurological deficit by NIH stroke scale score and lesion volume (r=0.584, P<0.0001). Logistic regression demonstrated NIHSS or lesion volume predicted capacity to consent.

CONCLUSIONS

Patients with acute stroke who retain capacity to consent have significantly smaller infarct volumes than those incapable of consent, and these are frequently below the limits where measurement error significantly compromises valid use of volumetric end points. Only a small proportion of patients with capacity to consent would be eligible for, and contribute usefully to, most acute stroke trial protocols.