Multiple Sclerosis Multidisciplinary Care: A National Survey and Lessons for the Global Community

BACKGROUND

Access to, standardization and reimbursement of multidisciplinary care for people with MS (PwMS) is lacking in many countries. Therefore, this study aims to describe the current multidisciplinary care for people with MS (PwMS) in Belgium and identify benefits, needs and future perspectives METHODS: A survey for PwMS questioned various aspects of MS and viewpoints on care. For MS nurses (MSN) and neurologists, employment, education, job-content, care organization and perspectives were inquired. Descriptive and univariate statistics were performed RESULTS: The PwMS survey comprised 916 respondents with a mean age of 46±12.7 years and 75,4 % of the respondents being female. The majority of the participants had relapsing remitting MS (60.8 %) and the mean patient determined disease steps (PDDS) was 2.0 (IQR=3). 65.3 % and 60.4 % of the PwMS reported having access to a multidisciplinary team (MDT) or MSN. Access to an MSN was associated with more frequent disease modifying treatment (p=.015), spasticity (p=.042) and gait treatment (p=.035), but also more physiotherapy (p=.004), driver's license adjustment (p<.001) and a higher employment rate (p=.004). MDT access was associated with more frequent symptomatic bladder treatment (p=.047), higher physiotherapy rate (p<.001), higher work- (p=.002), insurance- (p<.001) and home support measures (p=.019). PwMS without an available MDT more often indicated that MS care needs improvement (p<.001). MSN's (n = 22) were mainly funded through various budgets, including hospital and neurology practice budgets. Finally, 69 % and 75 % neurologists (n = 62) working without an MSN or MDT stated a need of such support and 61 % agreed that MDT's should be organized at hospital-network level CONCLUSION: MDT and MSN availability may enhance medical and socio-economic support for PwMS. Guidelines, alignment and reimbursement are needed.

The risk of secondary progressive multiple sclerosis is geographically determined but modifiable

Geographical variations in the incidence and prevalence of multiple sclerosis have been reported globally. Latitude as a surrogate for exposure to ultraviolet radiation but also other lifestyle and environmental factors are regarded as drivers of this variation. No previous studies evaluated geographical variation in the risk of secondary progressive multiple sclerosis, an advanced form of multiple sclerosis that is characterized by steady accrual of irreversible disability. We evaluated differences in the risk of secondary progressive multiple sclerosis in relation to latitude and country of residence, modified by high-to-moderate efficacy immunotherapy in a geographically diverse cohort of patients with relapsing-remitting multiple sclerosis. The study included relapsing-remitting multiple sclerosis patients from the global MSBase registry with at least one recorded assessment of disability. Secondary progressive multiple sclerosis was identified as per clinician diagnosis. Sensitivity analyses used the operationalized definition of secondary progressive multiple sclerosis and the Swedish decision tree algorithm. A proportional hazards model was used to estimate the cumulative risk of secondary progressive multiple sclerosis by country of residence (latitude), adjusted for sex, age at disease onset, time from onset to relapsing-remitting phase, disability (Multiple Sclerosis Severity Score) and relapse activity at study inclusion, national multiple sclerosis prevalence, government health expenditure, and proportion of time treated with high-to-moderate efficacy disease-modifying therapy. Geographical variation in time from relapsing-remitting phase to secondary progressive phase of multiple sclerosis was modelled through a proportional hazards model with spatially correlated frailties. We included 51 126 patients (72% female) from 27 countries. The median survival time from relapsing-remitting phase to secondary progressive multiple sclerosis among all patients was 39 (95% confidence interval: 37 to 43) years. Higher latitude [median hazard ratio = 1.21, 95% credible interval (1.16, 1.26)], higher national multiple sclerosis prevalence [1.07 (1.03, 1.11)], male sex [1.30 (1.22, 1.39)], older age at onset [1.35 (1.30, 1.39)], higher disability [2.40 (2.34, 2.47)] and frequent relapses [1.18 (1.15, 1.21)] at inclusion were associated with increased hazard of secondary progressive multiple sclerosis. Higher proportion of time on high-to-moderate efficacy therapy substantially reduced the hazard of secondary progressive multiple sclerosis [0.76 (0.73, 0.79)] and reduced the effect of latitude [interaction: 0.95 (0.92, 0.99)]. At the country-level, patients in Oman, Tunisia, Iran and Canada had higher risks of secondary progressive multiple sclerosis relative to the other studied regions. Higher latitude of residence is associated with a higher probability of developing secondary progressive multiple sclerosis. High-to-moderate efficacy immunotherapy can mitigate some of this geographically co-determined risk.

Early non-disabling relapses are important predictors of disability accumulation in people with relapsing-remitting multiple sclerosis

BACKGROUND

The prognostic significance of non-disabling relapses in people with relapsing-remitting multiple sclerosis (RRMS) is unclear.

OBJECTIVE

To determine whether early non-disabling relapses predict disability accumulation in RRMS.

METHODS

We redefined mild relapses in MSBase as 'non-disabling', and moderate or severe relapses as 'disabling'. We used mixed-effects Cox models to compare 90-day confirmed disability accumulation events in people with exclusively non-disabling relapses within 2 years of RRMS diagnosis to those with no early relapses; and any early disabling relapses. Analyses were stratified by disease-modifying therapy (DMT) efficacy during follow-up.

RESULTS

People who experienced non-disabling relapses within 2 years of RRMS diagnosis accumulated more disability than those with no early relapses if they were untreated (n = 285 vs 4717; hazard ratio (HR) = 1.29, 95% confidence interval (CI) = 1.00-1.68) or given platform DMTs (n = 1074 vs 7262; HR = 1.33, 95% CI = 1.15-1.54), but not if given high-efficacy DMTs (n = 572 vs 3534; HR = 0.90, 95% CI = 0.71-1.13) during follow-up. Differences in disability accumulation between those with early non-disabling relapses and those with early disabling relapses were not confirmed statistically.

CONCLUSION

This study suggests that early non-disabling relapses are associated with a higher risk of disability accumulation than no early relapses in RRMS. This risk may be mitigated by high-efficacy DMTs. Therefore, non-disabling relapses should be considered when making treatment decisions.

Redefining the Multiple Sclerosis Severity Score (MSSS): The effect of sex and onset phenotype

BACKGROUND

The Multiple Sclerosis Severity Score (MSSS) is a widely used measure of the disability progression rate. However, the global MSSS may not be the best basis for comparison between all patient groups.

OBJECTIVE

We evaluated sex-specific and onset phenotype-specific MSSS matrices to determine if they were more effective than the global MSSS as a basis for comparison within these subsets.

METHODS

Using a large international dataset of multiple sclerosis (MS) patient records and the original MSSS algorithm, we constructed global, sex-specific and onset phenotype-specific MSSS matrices. We compared matrices using permutation analysis.

RESULTS

Our final dataset included 30,203 MS cases, with 28.9% males and 6.5% progressive-onset cases. Our global MSSS matrix did not differ from previously published data (p > 0.05). The progressive-onset-specific matrix differed significantly from the relapsing-onset-specific matrix (p < 0.001), with lower MSSS attributed to cases with the same Expanded Disability Status Score (EDSS) and disease duration. When evaluated with a simulation, using an onset-specific MSSS improved statistical power in mixed cohorts. There were no significant differences by sex.

CONCLUSION

The differences in the disability accrual rate between progressive- and relapsing-onset MS have a significant effect on MSSS. An onset-specific MSSS should be used when comparing the rate of disability progression among progressive-onset cases and for mixed cohorts.

Management of adverse renal events related to alemtuzumab treatment in multiple sclerosis: a Belgian consensus

Alemtuzumab is a humanized monoclonal antibody indicated for the treatment of adult patients with relapsing–remitting multiple sclerosis with active disease. Multiple sclerosis (MS) patients treated with alemtuzumab are at increased risk for autoimmune adverse events (thyroid disorders, immune thrombocytopenia, and renal disease). The use of alemtuzumab has been associated with the development of renal immune-mediated adverse events in 0.3% of patients in clinical trials in MS, which generally occurred within 39 months of the last administration. Both anti-GBM disease and membranous nephropathy have been associated with the use of alemtuzumab. Early detection is necessary to allow for early diagnosis and prevent adverse renal and patient outcomes. Through the implementation of the risk minimization measures, patients can be diagnosed, and treated if needed, early allowing for generally favorable outcomes. This important goal can be reached through health care professional and patient education, careful analysis of the monthly lab tests, and close collaboration between the patient, neurologist, and the nephrologist. This article presents the consensus of Belgian MS specialists and nephrologists on the practicalities of diagnosis, management, and treatment of alemtuzumab-associated renal adverse events based on good clinical practice.

Treatment adherence in multiple sclerosis: a survey of Belgian neurologists

BACKGROUND

Poor treatment adherence is common among patients with multiple sclerosis (MS). This survey evaluated neurologists' perception of treatment adherence among MS patients.

MATERIALS AND METHODS

This questionnaire-based survey of Belgian neurologists treating MS patients was conducted between June and July 2014. Face-to-face interviews with the neurologists were based on a semistructured questionnaire containing questions regarding the perception of the treatment-adherence level.

RESULTS

A total of 41 neurologists participated in the survey. Of these, 88% indicated frequent discussions about treatment adherence as beneficial for treatment efficacy. The mean time spent on the treatment-adherence discussion during the initial consultation was 11 minutes, with 24% of doctors spending 5 minutes and 24% of doctors spending 10 minutes discussing this issue. The majority of neurologists (56%) perceived the adherence level in MS as good, and 12% perceived it as excellent. The majority of neurologists (64%) indicated intolerance as a main cause of poor adherence, and all neurologists reported insufficient efficacy as a consequence of nonadherence. The importance of adherence in the neurologists' practice was evaluated on a scale of 1-10, with 1= "not very important" and 10= "very important": 44% of doctors indicated a score of 10, and the mean score was 9.0.

CONCLUSION

Belgian neurologists consider treatment adherence in MS as essential for the benefits of therapies. However, although neurologists are aware of the consequences of nonadherence, they generally spend limited time discussing the importance of treatment adherence with their patients.

Cerebral blood flow and oxygen metabolism in symptomatic internal carotid artery occlusion by (traumatic) cervical artery dissection

The present study investigates whether cerebral infarction resulting from internal carotid artery occlusion by cervical dissection is due to emboli, released from a superimposed luminal thrombus, or is due to haemodynamic failure and hypoperfusion. Ten patients with a history of stroke and with a visible cerebral infarct on computed tomographic scan, due to cervical dissection and thrombosis of the internal carotid artery, were studied with positron emission tomography in order to assess the regional cerebral blood flow (rCBF), the regional cerebral metabolic rate of oxygen (rCMRO2) and the regional oxygen extraction fraction (rOEF) in different regions of the brain. rCBF and rCMRO2 were only decreased in the infarct area but not in the peri-infarct zone or elsewhere in the brain. As rOEF was not increased in the affected cerebral hemisphere, the present study suggests artery-to-artery embolism rather than a haemodynamic event as the cause of the stroke. Use of anticoagulants thus appears to be the appropriate treatment in the acute stage.

Long-term follow up of glatiramer acetate compassionate use in Belgium

Between June 1995 and November 1998, 228 patients with relapsing-remitting Multiple Sclerosis started treatment with glatiramer acetate (Copaxone) 20 mg once daily in the frame of a "compassionate use" protocol in 15 Belgian centers. Following an average treatment period of 5.8 years, treating neurologists were requested to fill in follow-up forms indicating neurological disability status and side effects during the previous 6 months. These data were available for 134 patients. In this group, the Expanded Disability Status Scale (EDSS) improved in 26.3% of patients. An additional 36.8% of patients remained neurologically stable. The Ambulation Index (AI) showed similar results: 12.5% of patients improved, 50% of patients remained stable, and 37.5% worsened. Only 10% of patients dropped out due to several reasons. The adverse events occurring in the period preceding the follow-up survey were non-serious and consistent with the current product information of glatiramer acetate. Among the 94 patients no longer followed-up in the compassionate program, reasons for lost to follow-up were obtained for 63; most of them (41) had stopped GA treatment or switched to another disease-modifying treatment. Overall these results are very similar to the ones reported in the extension study of the pivotal trial (Johnson et al., 2000), and indicate that patients treated with glatiramer acetate have a better outcome than expected on the basis of the natural course of the disease. Despite limitations of the study design, this report confirms the sustained efficacy of glatiramer acetate in reducing the disease progression in patients with relapsing-remitting multiple sclerosis treated in day-to-day clinical practice.

Cerebral bloodflow and oxygen metabolism in borderzone and territorial infarcts due to symptomatic carotid artery occlusion

It remains controversial whether borderzone infarcts are due to compromised cerebral perfusion and whether territorial infarcts are caused by artery-to-artery emboli in case of occlusion of the internal carotid artery. The present positron emission tomography study compares with normal controls, the average regional cerebral bloodflow (rCBF), regional oxygen extraction fraction (rOEF) and regional cerebral metabolic rate for oxygen (rCMRO(2)) in the infarct area, the peri-infarct zone, the remaining homolateral hemisphere and in the contralateral hemisphere of 10 patients with borderzone and 17 patients with territorial infarcts, due to internal carotid artery occlusion by atherosclerosis and by cervical dissection. The steady-state technique with oxygen-15 was used. A nearly significant increase of rOEF with lowered rCBF and rCMRO(2) was observed in the peri-infarct zone of patients with territorial infarcts. In patients with borderzone infarcts rCMRO(2) was decreased in the peri-infarct zone, in the remaining homolateral hemisphere and in the contralateral hemisphere without changes in rCBF and rOEF. The present study finds no arguments that impaired cerebral perfusion is a more frequent cause of borderzone than of territorial infarcts.

Assessment of neuroinflammation and microglial activation in Alzheimer's disease with radiolabelled PK11195 and single photon emission computed tomography. A pilot study

OBJECTIVES

Inflammation contributes to degeneration in Alzheimer's disease (AD), not simply as a secondary phenomenon, but primarily as a significant source of pathology. [(123)I]iodo-PK11195 is a single photon emission computed tomography (SPECT) ligand for the peripheral benzodiazepine receptor, the latter being expressed on microglia (brain resident macrophages) and upregulated under inflammatory circumstances. The objectives were to assess AD inflammation by detecting [(123)I]iodo-PK11195 uptake changes and investigate how uptake values relate with perfusion SPECT and neuropsychological findings.

METHODS

Ten AD and 9 control subjects were included. [(123)I]iodo-PK11195 SPECT images were realigned into stereotactic space where binding indices, normalized on cerebellar uptake, were calculated.

RESULTS

The mean [(123)I]iodo-PK11195 uptake was increased in AD patients compared with controls in nearly all neocortical regions; however, statistical significance was only reached in the frontal and right mesotemporal regions. Significant correlations were found between regional increased [(123)I]iodo-PK11195 uptake and cognitive deficits.

CONCLUSIONS

[(123)I]iodo-PK11195 is a cellular disease activity marker and allows in vivo assessment of microglial inflammation in AD.

Cerebral blood flow and oxygen metabolism in symptomatic internal carotid artery occlusion by atherosclerosis and by cervical dissection

Symptomatic internal carotid artery occlusion by atherosclerosis and by cervical dissection are distinct conditions with different long-term prognoses. The purpose of the present study is to investigate if regional cerebral blood flow and oxygen metabolism, after onset of stroke, differ between both conditions. Seventeen patients with symptomatic unilateral atherosclerotic internal carotid occlusion and 10 patients with symptomatic internal carotid occlusion due to cervical dissection were submitted to a positron emission tomographic (PET) study between 1 and 2 months after stroke onset. The steady state technique with 15O was used in order to determine regional cerebral blood flow, regional oxygen extraction fraction, and regional cerebral metabolic rate for oxygen in the infarct area, the peri-infarct zone, the remaining homolateral hemisphere, and the contralateral hemisphere. The results were compared between both patient's populations. The patients with cervical dissection were on average much younger than those with atherosclerotic occlusion, but neurological impairment on admission and disability at 3 months were comparable. Between both patient populations, no differences in rCBF, rOEF, and rCMRO2 could be demonstrated in the different regions of interest when the results were age-adjusted. Except for age-related changes, no differences in PET findings could be demonstrated between patients with symptomatic internal carotid occlusion caused by either atherosclerosis or cervical dissection.

Imaging of the 5-HT2A system: age-, gender-, and Alzheimer's disease-related findings

Serotonin (5-HT) and more specifically the 5-HT(2A) receptor is involved in cognitive and non-cognitive behavior and plays an important role in Alzheimer's disease (AD). The objective was to assess the 5-HT(2A) binding potential (BP) in healthy volunteers and AD with SPECT and 123I-5-I-R91150, a selective radio-iodinated 5-HT(2A) receptor antagonist. Twenty-six controls and nine AD patients were included. A semiquantitive analysis with normalization on cerebellar uptake provided estimates of BP for 26 cortical regions of interest. An age-related decline of neocortical BP was found (11.6% per decade). Compared to age-matched controls, a generally decreased neocortical BP in AD was found with a significant regional reduction in the orbitofrontal, prefrontal, lateral frontal, cingulate, sensorimotor, parietal inferior, and occipital region. These results are in line with previous postmortem, in vitro, and PET findings. The age-related decline highlights the necessity for matched advanced age study samples. The fact that the 5-HT(2A) receptor is differentially affected in AD patients has implications for both the etiological basis and therapeutic management of AD.

57Co SPECT, 99mTc-ECD SPECT, MRI and neuropsychological testing in senile dementia of the Alzheimer type

Inflammatory mechanisms contribute to the pathophysiology of senile dementia of the Alzheimer type (sDAT). Previous studies have shown that 57Co single photon emission computed tomography (SPECT) is able to visualize inflammatory lesions, probably by means of the final common pathway of Ca2+ homeostasis disturbance in both neuronal degeneration and inflammation. The aims of this study were: (1) to detect 57Co SPECT changes in sDAT patients; (2) to correlate these findings with those of conventional neuroimaging techniques and neuropsychological testing (NPT); and (3) to compare 57Co SPECT findings in sDAT patients with those in other types of dementia. Six patients suffering from probable sDAT were included and compared with four patients suffering from other types of dementia. All patients had a magnetic resonance imaging (MRI) scan, NPT, 57Co and 99mTc-ethyl cysteinate dimer (ECD) SPECT scan. Perfusion SPECT images were semiquantitatively evaluated by comparison with an age-matched normal database, while 57Co SPECT scans were assessed qualitatively. MRI and 99mTc-ECD SPECT scans yielded conclusive results with regard to the exclusion of other pathologies and the confirmation of the diagnosis. Using visual analysis, 57Co SPECT scans were unable to show any regional raised uptake, irrespective of the disorder, depth or extent of the perfusion defects, presence of atrophy on MRI or the results of NPT.

Parkinsonism in patients with vascular dementia: clinical, computed- and positron emission-tomographic findings

PURPOSE

The present study investigates the vascular nature of parkinsonian features in patients with 'probable' vascular dementia.

PATIENTS AND METHODS

Forty patients with vascular dementia were studied with positron emission tomography (PET) using the steady state technique with (15)O in order to assess regional cerebral blood flow (rCBF), regional oxygen extraction rate (rOER) and regional metabolic rate for oxygen (rCMRO(2)) in different brain regions. The findings in 10 patients with (VaDP) were compared to 30 without parkinsonism (VaD).

RESULTS

The clinical and computed tomographic findings in the parkinsonian patients were similar to those described in the literature as probable vascular parkinsonism. The PET results showed decreased rCBF and rCMRO(2) in the frontal and parietal cortices and in the striatum of the VaDP compared to the VaD group. The decrease of rCBF and rCMRO(2) in frontal and parietal cortices is due to the more severe mental changes in the VaDP group. In the VaDP patients rCBF and rCMRO(2) were more decreased and rOER increased in the striatum contralateral to the most affected parkinsonian side.

CONCLUSION

Our PET findings show that local ischemic changes in the striatum contribute to parkinsonism in vascular dementia patients.

Accurate differentiation of parkinsonism and essential tremor using visual assessment of [123I]-FP-CIT SPECT imaging: the [123I]-FP-CIT study group

OBJECTIVE

To evaluate whether visual assessment of [123I]-FP-CIT (DaTSCAN, Nycomed Amersham, plc) single photon emission computerized tomography (SPECT) images can differentiate between parkinsonism and essential tremor (ET).

METHODS

[123I]-FP-CIT SPECT imaging was conducted in a six-center study of 158 patients with a clinical diagnosis of parkinsonism compared with 27 ET cases and 35 healthy volunteers. Striatal uptake of the radioligand was graded normal or abnormal, and abnormal images were further graded to three levels of severity. An institutional read whereby each center visually assessed the images blinded to the clinical data and a consensus blinded read by a panel of five was undertaken.

RESULTS

The institutional reading scored 154 of 158 cases of parkinsonism abnormal, all 27 cases of ET as normal, and 34 of 35 healthy volunteers as normal compared with the consensus blinded read scoring 150 cases of parkinsonism as abnormal, 25 ET cases as normal, and 33 healthy volunteers as normal. Sensitivity for the clinical diagnosis of parkinsonism was 97% and specificity for ET was 100% for the institutional read, whereas sensitivity was 95% and specificity 93% for the consensus blinded read. Semiquantitative analysis of specific: nonspecific caudate and putamen uptake were consistent with the results of visual inspection.

CONCLUSION

Visual assessment of [123I]-FP-CIT SPECT images is an easily applied diagnostic test which is helpful in the differential diagnosis of tremor disorders and in confirming a clinical diagnosis of a hypokinetic-rigid syndrome.

Acetazolamide vasoreactivity in vascular dementia: a positron emission tomographic study

The present study investigates the vasoreactivity of the brain in patients with large infarcts and dementia (multi-infarct dementia; MID) and in patients with microangiopathy, lacunes, white matter changes and dementia (lacunar dementia; LD) using positron emission tomography (PET) and 13NH3 as regional cerebral blood flow (rCBF) tracer. In the control group, an increase in rCBF ranging from 32 to 43% was found in all brain regions after intravenous acetazolamide administration. In both the MID group and the group with multiple infarcts without dementia, moderate loss of vasoreactivity was observed in the frontal, temporal and parietal cortex compared to the control values. Vasoreactivity was severely impaired in all cerebral regions of the LD group and restricted to the thalamus in the group with lacunes and white matter changes without dementia (lacunar stroke; LS). This suggests that global loss of vasoreactivity is not a determining factor in the occurrence of MID, but might be important in LD. The present study shows that loss of the vascular reserve leading to exhausted metabolic reserve of the whole brain is one of the possible mechanisms for the occurrence of vascular dementia.

Biodistribution and dosimetry of carbon-11-methoxyprogabidic acid, a possible ligand for GABA-receptors in the brain

Carbon-11-methoxyprogabidic acid (11C-MPGA) was recently synthetized as a possible ligand for PET studies of gamma-amino-butyric acid (GABA) receptors in the brain. The data for human absorbed dose estimates are calculated based on the biodistribution of 11C-MPGA in mice and humans.

METHODS

Eighteen mice were killed at preset time intervals after an intravenous bolus injection of 3.7 MBq (100 microCi) 11C-MPGA. Time-activity curves were reconstructed for several organs. Three healthy men each had whole-body PET scans after an intravenous bolus injection of 37 MBq (1 mCi) to determine activity in the critical organs. Animal data were fitted into these human findings to calculate residence times, and the MIRDOSE 3 protocol was used to calculate the radiation absorbed dose.

RESULTS

Animal studies demonstrated a rapid distribution of 11C-MPGA in several organs. The highest activity was detected in the intestines, liver and kidneys. Brain activity was low throughout compared to these organs. The human whole-body study yielded similar results, with the intestines, liver and kidneys showing the highest activity. The estimated dose to the urinary bladder compartment turned out to be significant. The mean effective dose was 4.8 microSv/MBq (s.d.= 0.5 microSv/MBq).

CONCLUSION

PET studies using 185 MBq (5 mCi) 11C-MPGA are within the International Commission on Radiological Protection risk Category II for healthy volunteers.

Positron emission tomography in vascular dementia

BACKGROUND

Vascular dementia (VaD) is an ill-defined entity. It is not known how acute brain failure related to stroke becomes chronic leading to dementia.

PURPOSE

The present study investigates whether positron emission tomography (PET) can detect different metabolic patterns in VaD.

PATIENTS AND METHODS

Four groups of stroke patients were selected. The PET findings of 14 stroke patients with multiple large infarcts and dementia (MID) and 14 without dementia (MS) were compared. Sixteen stroke patients with lacunes, leukoaraiosis and dementia (LD) were assessed against nine without dementia (LS). The PET examination utilised the 15-O-steady-state technique in order to determine regional cerebral blood flow (rCBF), regional oxygen extraction rate (rOER) and regional cerebral metabolic rate for oxygen (rCMRO2) in different pre-established cortical, subcortical and cerebellar regions.

RESULTS

Decreased coupled mean rCBF and rCMRO2 with comparable rOER values were observed in all cerebral regions except in the cerebellum of the MID compared to the MS group. In the LD group mean rCBF and rCMRO2 were decreased with increased rOER in all cerebral regions except in the cerebellum compared to the LS group.

CONCLUSIONS

The PET findings in demented patients with multiple large infarcts are in agreement with the concept of multi-infarct dementia. In demented patients with lacunes and leukoaraiosis, the PET pattern suggests a state of misery perfusion not only in the deep structures but also in the whole cerebral cortex. The present PET study argues that there are at least two possible mechanisms that can explain the occurrence of VaD in stroke patients.

PET studies in epilepsy

Positron emission tomography (PET) plays a major role in the pre-surgical evaluation of patients with refractory partial epilepsy. In this review we discuss the limitations of PET data, the possibilities of fluorodeoxyglucose PET studies, neuroreceptor PET studies and alternatives, such as SPECT and MRI.

Co-registration of PET and MRI in different courses of MS using Cobalt-55 as a Calcium-tracer

Multiple Sclerosis (MS) is an auto-immune central nervous system (CNS) inflammation. At this moment, MRI is the most accurate paraclinical test in MS to monitor disease activity, although poorly correlated with clinical impairment. PET using Co-55 as a Ca-tracer may visualize Co-transport across the neuronal membrane, Ca-mediated inflammatory processes and passive leakage through a breach in the blood-brain barrier. Co-registration of MRI and Co-PET may actually allow identification of clinically active lesions. MRI and Co-PET were performed as described elsewhere. Based on a statistic parametric mapping (SPM-96)-software package, MRI and Co-PET were superimposed. A semi-automated technique was used to count the MS-lesions. We included four groups of eight MS-patients with relapsing-remitting (RR), primary progressive (PP), progressive relapsing (PR) and secondary progressive (SP) courses and eight healthy volunteers. MS was assessed in terms of impairment using Kurtzke's Expanded Disability Status Scale (EDSS) and Scripps Neurological Rating Scale (NRS). Co-PET displayed focal uptake throughout the MS brain, both in the grey and white matter. All four patients groups (as compared to controls) demonstrated a more inhomogeneous distribution of Co-spots with a tendency to show clustering, most evident in RR-MS. SPM-analysis revealed an essentially different distribution pattern of MS spots on MRI and Co-PET. (Merging of) Co-PET and MRI may eventually form complementary tools for identifying clinically relevant lesions, thus providing a more reliable secondary outcome measure in MS.

Crossed cerebellar diaschisis after middle cerebral artery infarction

It is unclear whether crossed cerebellar diaschisis (CCD) is merely an epiphenomenon, as its clinical significance remains uncertain. We retrospectively analysed the positron emission tomographic (PET) findings in 28 patients with a chronic, stable middle cerebral artery (MCA) infarct and in 22 controls, using the steady state technique and 15O. Also, the Orgogozo scores on admission and at the time of the PET examination were compared in the patients with MCA infarction. Based on the asymmetry index and the 95% confidence limits for regional cerebellar blood flow (rCBF) and oxygen consumption (rCMRO2) in the control group, the stroke patients were subdivided in a group with (n = 8) and a group without (n = 20) CCD. The CCD group had lower values of rCMRO2 in the infarct and border areas compared to those of the non-CCD patients. The infarct location within the MCA territory was similar but the size was somewhat larger in the CCC group. The degree of neurological improvement was better in the non-CCD group. Although persistence of CCD has no real clinical significance it appears to be correlated to more severe and widespread ischaemia in the affected MCA territory and to the lack of significant clinical improvement.

Cerebral oxygen metabolism in patients with progressive supranuclear palsy: a positron emission tomography study

To investigate cerebral oxygen metabolism in progressive supranuclear palsy (PSP), 5 patients with a clinical diagnosis of PSP and a variable degree of cognitive deficit were selected for positron emission tomography (PET) of the brain. In 4 of them, a significant decrease in oxygen metabolism was found in all cortical regions, without frontal accentuation. In the group as a whole, this decrease was even slightly more marked in parietal and temporal regions. These findings are not consistent with earlier PET studies that demonstrated frontal targeting of hypometabolism in PSP patients. Part of this discrepancy can be explained by differences in methodology, although the use of different clinical criteria and overlap of PSP with other neurodegenerative diseases must be taken into account. It is concluded that the absence of frontal hypometabolism on PET examination does not exclude the diagnosis of PSP.

Late-onset epileptic seizures in patients with leukoaraiosis: a positron emission tomographic study

Leukoaraiosis, found on computed tomographic scans of the brain, is suspected to be of ischemic origin and is frequently associated with progressive decline of cognitive functions in elderly persons. Some of them also develop late-onset epilepsy. The present positron emission tomographic study investigates if these seizures in mentally nonaffected patients with leukoaraiosis are related to an underlying ischemic process. Patients with leukoaraiosis and late-onset seizures have a more important decline of regional blood flow and oxygen consumption in the cortical areas, compared to normal age-matched controls, to patients with cryptogenic symptomatic late-onset epilepsy and to patients with a similar degree of leukoaraiosis but without epilepsy. The present study suggests that both the late-onset seizures and the leukoaraiosis in patients with, at that time, no obvious mental deterioration are premonitory signs of an encephalopathy of unknown origin, possibly leading to cognitive decline.

Ipsilateral thalamic diaschisis after middle cerebral artery infarction

The significance of ipsilateral thalamic diaschisis (ITD) among patients with chronic, stable middle cerebral artery (MCA) infarcts was investigated. Twenty eight subjects with chronic MCA infarction and twenty two normal controls were studied with positron emission tomography (PET), using the steady state technique with 15O. Stroke patients were subdivided into a group with ITD (n = 12) and a group without ITD (n = 16). Patients with ITD had greater decreases of regional blood flow (rCBF) and oxygen consumption (rCMRO2) in the infarcted MCA territory, compared to MCA infarction without ITD. The neurological deficits at the time of PET scanning were similar between both groups. Extent of infarction by CT brain scan appeared more predominant in peri-insular regions of patients with ITD, while in non diaschisis patients infarcts were more widely distributed throughout the MCA territories. Occurrence of ITD and of crossed cerebellar diaschisis (CCD) did not correlate. Occurrence of ITD seems to be linked to diffuse reductions of blood flow and oxygen metabolism in cortical territories of the MCA. Mechanisms of ITD were different from those of CCD.

Positron emission tomographic study of late-onset cryptogenic symptomatic seizures

Ten patients with epilepsy of unknown origin, starting after the age of 50 years, and without clear evidence of cognitive decline were studied with positron emission tomography, using the steady state technique with 15O. Cerebral blood flow and oxygen metabolism were significantly decreased in all cortical areas. No focal areas of hypometabolism were detected. Treatment with phenytoin did not influence the results. It is suggested that late-onset seizures could be the premonitory signs of a progressive encephalopathy of unknown origin.

Positron emission tomography in spastic diplegia

In this study, three patients with spastic diplegia were examined with magnetic resonance imaging (MRI) and positron emission tomography (PET), using the steady state technique with 15O. Two of them had untractable seizures and mental retardation. On MRI the cortical structures were normal; increased T2 signals in the periventricular white matter in the second patient were the main findings. PET scan showed in the two patients with a seizure disorder and mental retardation a large left cortical area of decreased regional blood flow and oxygen consumption during the interictal phase. The third patient without epileptic spells had a normal PET scan examination. It is concluded that the epileptic disorder in two of our cases is due to an additional cortical lesion, while the spastic diplegia is caused by subcortical white matter destruction.

A double-blind study of neurotropin in patients with acute ischemic stroke

Neurotropin was found to reduce brain oedema in an experimental model of brain infarction in the guinea-pig. A randomized double-blind controlled trial with Neurotropin was performed in 220 patients admitted within 24 h after an acute ischemic stroke. 35 of the neurotropin and 41 of the placebo-randomized patients had to be excluded. 10 included patients in the neurotropin and 13 in the placebo-treated group died within the study period of 15 days. A better clinical outcome was observed in the 65 included surviving neurotropin compared with the 56 placebo-treated patients. The size of the infarct and of the oedema zones was significantly more decreased on CT scans from Day 11 compared with Day 3 after stroke in the neurotropin than in the placebo treated group. Neurotropin is helpful in treating brain oedema, related to acute ischemic stroke.

Clinical and neurophysiological correlations in patients with refractory partial epilepsy and intracranial structural lesions

Twenty patients (13 males, 7 females), who presented with refractory partial epilepsy and a CT and/or MR detected intracranial intra-axial structural lesion were admitted to the University of Gent Epilepsy Monitoring Unit. Mean duration of the epilepsy was 17 years (2-47 years). All patients were enrolled in a comprehensive presurgical protocol including neurological examination, video-scalp-EEG monitoring with prolonged interictal and ictal recording, neuropsychological assessment and positron emission tomography (PET). Intracranial EEG monitoring was performed in 5 patients in whom discrepancies between different tests were found during the non-invasive evaluation. Clinical neurological examination was normal in 16 patients; 4 patients had a mild contralateral hemiparesis. Lesions were mainly located in the temporal lobe (55%). Most patients presented with complex partial seizures (90%). Clinical seizure characteristics correlated well with the lesion location in 55% of patients. Interictal EEG showed focal epileptic activity and focal slowing in respectively 85% and 30% of patients. Interictal EEG lateralization was congruent with the side of the lesion in 17 patients (85%). Interictal EEG localization was congruent with the lobe of the lesion in 13 patients (65%). Ictal EEG lateralized correctly in 14 patients (70%) and localized correctly in 10 patients (50%). Neuropsychological assessment lateralized and localized congruently in respectively 8/17 (47%) and 7/17 (41%) of patients. Interictal PET showed focal interictal hypometabolism, congruent with the lesion, in 13/16 (81%) of patients. Intracranial EEG was congruent with the lesion location in 3 patients but non-congruent in 2 patients. All patients underwent surgical procedures: average follow-up was 14 months (6-24 months). Complete surgical removal of the lesion with free margins resulted in a more than 90% reduction of seizures without postoperative neurological deficit in 12/13 patients.

Neurotropin treatment of brain edema accompanying acute middle cerebral artery infarction

The present study is a second analysis of a randomized double-blind controlled trial on the efficacy of neurotropin on brain edema in a subgroup of patients with acute middle cerebral artery infarct treated within 24 hours. Neurotropin is a biological extract that specifically inhibits the release of bradykinin. The mortality rate was significantly lower in the neurotropin than in the placebo group. In the surviving patients the neurological deficit decreased to a significantly greater extent by neurotropin therapy after 15 days. The CT scan findings in the brain of the neurotropin-treated patients demonstrated a significant reduction in the size of the infarct and of the edematous area. Patients with middle cerebral artery infarct, which is prone to give rise to fatal intracranial hypertension, may derive great benefit from treatment of brain edema with neurotropin.

A positron emission tomography study of patients with acute carbon monoxide poisoning treated by hyperbaric oxygen

Seven patients with an acute and severe carbon monoxide intoxication were treated with hyperbaric oxygen and underwent a positron emission tomographic examination 2-5 days after the acute event. Although the final clinical outcome was good in all patients, ischaemic changes were observed. Three patients with temporary sequelae after hyperbaric oxygen treatment showed the most severe changes, mainly in striatum and thalamus. Although positron emission tomographic examination cannot predict the final outcome, it can show the regions at risk for development of late complications following carbon monoxide poisoning.

Positron emission tomography study of the human hypothalamus during normal ageing and in ischemic and degenerative disorders

Regional blood flow and oxygen metabolism were determined by positron emission tomography, using the steady state technique with 15O, in the hypothalamus and in the whole brain of fifty two normal persons and patients suffering from cerebral ischemia and degenerative dementia. During normal ageing regional blood flow and oxygen consumption appeared to increase slightly in the hypothalamus and to decrease in the whole brain in 24 persons. In the young age group the hypothalamus was more protected against ischemia than in the elderly group. In the aged group with cerebral ischemia and degenerative dementia regional blood flow and oxygen consumption were decreased in the hypothalamus to the same extent as in the whole brain.

Significance of white matter lucencies in posthypoxic-ischemic encephalopathy: comparison of clinical status and of computed and positron emission tomographic findings

The clinical status and the computed and positron tomographic findings were compared in 10 patients with sequelae of hypoxic-ischemic encephalopathy after cardiopulmonary arrest and successful resuscitation. Conscious patients with moderate neuropsychiatric deficits had no significant computed tomography (CT) scan changes and normal values of regional cerebral blood flow and oxygen consumption, while patients in vegetative state had definite cerebral atrophy on CT scan and a severe and widespread decrease of regional cerebral blood flow and oxygen consumption. This decrease was even more pronounced in vegetative patients with the worst neurological score and with CT scans demonstrating additional diffuse white matter lucencies and hypodensities in the basal ganglia. In this group of patients increased regional oxygen extraction rates mainly in the white matter indicated the occurrence of delayed ischemic changes. The positron emission tomography and CT findings correlated well with the degree of posthypoxic-ischemic damage and the clinical status of the studied subjects.

Does the severity of leukoaraiosis contribute to senile dementia? A comparative computerized and positron emission tomographic study

The present study evaluates the origin, severity and location of leukoaraiosis in senile dementia and in normal ageing. The regional white-matter lucency scores, determined on computed-tomographic scan of the brain, are compared to the regional blood flow, oxygen extraction rate and oxygen consumption, determined by the [15O] steady-state technique with positron emission tomography. Thirty patients, classified according to the presence or absence of leukoaraiosis and their mental status, are examined. The occurrence and severity of dementia appear to be mainly correlated to decreased blood flow and oxygen metabolism in the frontal, temporal and parietal cerebral cortex. Leukoaraiosis in demented and nondemented patients is associated with lowered blood flow in the frontal and parietal white matter. The regional lucency score is increased, and blood flow and oxygen consumption decreased in the frontal white matter of severely demented patients. Frontal leukoaraiosis contributes to dementia and is probably of ischemic origin, while parietal and occipital leukoaraiosis is due to wallerian degeneration.

Transoesophageal echo-Doppler in patients suspected of a cardiac source of peripheral emboli

The initial results of a controlled and partly blinded study aimed at evaluating the accuracy of transoesophageal echo-Doppler in detecting cardiac sources of peripheral emboli are reported. A total of 120 consecutive patients suspected of acute embolic events were entered. After completion of all investigations, the patients were classified into three groups: patients who had definitely not suffered an embolic event (controls; n = 56); patients in whom the differentiation between local thrombosis, embolic event originating from a diseased infarct-related artery or embolic event from a cardiac source was not possible (questionable cases; n = 24) and patients in whom a cardiac source of a definite embolic event was highly suspected (cardiac emboli; n = 40). Isolated interatrial septum anomaly and mitral valve prolapse were as frequent in the control group as in the embolism group. Transoesophageal echo-Doppler had a sensitivity of 83% and a specificity of 86% in correctly assigning a patient to the cardiac embolism group or to the control group. The positive and negative predictive values were 80% and 87% respectively. It is concluded that transoesophageal echo-Doppler is highly sensitive but is also specific in demonstrating cardiac sources of peripheral emboli.