FDG-PET improves tumour detection in patients with paraneoplastic neurological syndromes

To determine the usefulness of [18F]fluorodeoxyglucose (FDG) whole body FDG-PET in the diagnosis of tumours in patients with paraneoplastic neurological syndromes (PNS), we prospectively studied 20 patients with paraneoplastic antibodies in whom conventional imaging gave negative or inconclusive results for the presence of tumour. All 20 patients had neurological manifestations compatible with PNS and well-characterized paraneoplastic antibodies (12 anti-Hu, one anti-Hu and anti-CV2, one anti-CV2, four anti-Yo, one anti-Ri and one anti-amphiphysin). The mean delay between the onset of neurological symptoms and FDG-PET was 10 months (range 1-54). In these 20 patients, abnormal uptake was demonstrated in 18 patients, with some patients having abnormal signal in several areas. We observed abnormal uptake in the mediastinum (13 cases), lung (two cases), breast (two cases), parotid gland (one case), or the cervical, supraclavicular or axillary lymph nodes (seven cases). Following FDG-PET, the histological diagnosis of the tumour was made in 14 patients (small cell lung carcinoma in eight cases, breast adenocarcinoma in two, lung adenocarcinoma in two, axillary metastasis of ovary carcinoma in one, and malignant thymoma in one). Two other patients with abnormal FDG uptake showed radiological evidence of lung cancer, but a histological diagnosis could not be obtained. In two other patients, initial FDG-PET showed abnormal FDG uptake that was not confirmed a few months later by repeat FDG-PET. In the two patients with negative FDG-PET, peritoneal carcinomatosis was diagnosed in one and no tumour was found in the other. In our series, the sensitivity of FDG-PET for tumour detection was >83% demonstrating a clear role of this technique in the management of patients with PNS. However, in our series, the specificity of FDG uptake was only 25% due to unexplained abnormal FDG uptake in three patients and in abnormal FDG uptake due to a benign tumour in one patient. Over the study period, we saw 73 other patients with PNS and paraneoplastic antibodies. A tumour was demonstrated in 71 out of 73 by conventional techniques. Since false-positive and false-negative results are possible with FDG-PET and in most patients with PNS, the tumour is demonstrated by conventional techniques, we believe that FDG-PET should be reserved, at the moment, for patients with well-defined PNS antibodies when conventional imaging fails to identify a tumour or when lesions are difficult to biopsy.

Large-artery stroke in a young patient with Crohn's disease. Role of vitamin B6 deficiency-induced hyperhomocysteinemia

An increased incidence of ischemic stroke has been reported in patients with Crohn's disease. Cerebral infarcts are usually considered as a complication of the hypercoagulable state associated with this inflammatory bowel disease (IBD). The association between Crohn's disease, hyperhomocysteinemia and large-artery stroke of the young has rarely been reported. A 39-year-old woman, with prior medical history of Crohn's disease and hypertension, presented with an ischemic stroke of the left internal carotid artery (ICA) territory. Etiological workup disclosed bilateral high-grade ICA stenosis and atheroma of the subclavian and vertebral arteries. Exhaustive search for prothrombotic factors showed inflammation, with an increased level of fibrinogen and factor IX, and a marked hyperhomocysteinemia. Both vitamin B1 and vitamin B6 plasmatic levels were decreased. Heterozygous C677T methylene-tetrahydrofolate reductase gene mutation was present. This observation highlights the combined proatherogenic effect of vitamin B deficiency-induced hyperhomocysteinemia and inflammation leading to large-artery stroke of the young in the setting of Crohn's disease. Our case report stresses the importance of vitamin deficiency screening in patients with IBD in terms of stroke prevention.

Intravenous r-TPA in vertebrobasilar acute infarcts

Presented are the clinical data of 18 consecutive patients who were treated by IV recombinant tissue plasminogen activator (r-TPA) for suspected vertebrobasilar (VB) acute ischemia within 7 hours. The mean delay for treatment was 5 +/- 3.6 hours. Mean baseline NIH Stroke Scale score was 17 +/- 4. At 3 months, 10 patients were independent (modified Rankin Scale [mRS] score = 0 to 2), whereas 8 patients showed a poor outcome (mRs = 3 to 6). IV r-TPA in VB ischemia in a 7-hour window may be safe and efficient.

Thrombophlébite cérébrale révélée par une hémorragie sous-arachnoïdienne

Headache of subacute onset, associated with other signs of increased intracranial pressure, represents the most frequent symptom of cerebral thrombophlebitis. We report a case of subarachnoid hemorrhage as a rare presentation of cerebral thrombophlebitis. Unfractionated intravenous heparin treatment resulted in resolution of subarachnoid hemorrhage on control brain CT scan and quick clinical recovery.

Syndrome pseudo-démentiel révélateur d’une fistule artério-veineuse durale

We describe a case of a 70-Year-old man who presented subacute pseudo-dementia due to a dural fistula. Neurological assessment and the reversibility of the symptoms after embolization support the originality of this observation.

Évaluation du niveau d’information concernant l’accident vasculaire cérébral des patients admis dans une unité neurovasculaire française

Admission delay remains the main cause for stroke patient exclusion from urgent therapeutic protocols. Public lack of knowledge about stroke symptoms may result in delay in seeking medical care and late presentation at hospital. Lack of knowledge of risk factors for stroke may also hamper compliance with stroke prevention practices. The aim of this prospective study using a standardized questionnaire was to evaluate the stroke awareness of acute stroke patients in France. From July 2, 1998 to July 2, 1999, 166 consecutive stroke patients were admitted at our stroke unit. Among the 91 patients who were able to answer the questionnaire during the first 48 hours, only 19 patients (21 p.cent) thought they were having a stroke before their arrival at the hospital, 38 patients (42 p.cent) did not know a single sign of stroke and 33 patients (36 p.cent) did not know a single risk factor of stroke. The most common risk factors named by the patients were smoking and hypercholesterolemia (named by 31 patients (34 p.cent) and 19 patients (21 p.cent), respectively). The most common warning signs named by the patients were paralysis of one side of body or one limb and speech disturbance (named by 40 patients (44 p.cent) and 15 patients (16 p.cent), respectively). Female sex and "knowing somebody who had a stroke" were significantly associated with awareness of signs of stroke in multivariate analysis. Educational public programs regarding stroke awareness are needed in France. Educational campaigns must stress the risk factors and symptoms of stroke and the appropriate response in the hopes of reducing admission delay and improving stroke prevention.

Reactivity of flavonoids with 1-hydroxyethyl radical: a γ-radiolysis study

We have investigated the reactivity between 11 flavonoids and 1-hydroxyethyl radical (HER). HER was recently implicated in many liver injuries induced by ethanol intoxication. In this study, HER was generated by radiolysis; due to its reaction rate, HER is well known to be responsible for solute degradation in irradiated ethanol. Flavonoid ethanol solutions were irradiated with gamma-rays and the flavonoid degradation was followed by HLPC. We observed the degradation of flavonols while all other flavonoids (flavones, flavanones, dihydroflavonols, catechins) were not degraded after irradiation. The major radiolysis products were identified by NMR and LC-MS and we concluded that flavonols were essentially transformed into depsides. We proposed a reactivity mechanism between flavonols and HER. In a first step, H-transfer occurred from the 3-OH group to HER. Afterwards, C-ring opening occurred due to the presence of the 2,3-double bond in flavonols. Finally, we calculated the reaction constants in order to evaluate the antioxidant activity of flavonols against HER and to compare it with reference compounds.

Mechanisms of transformation of the antioxidant kaempferol into depsides. Gamma-radiolysis study in methanol and ethanol

In this study, we irradiated the antioxidant kaempferol in ethanol and methanol solutions with gamma rays at doses ranging from 0.2-20 kGy. NMR and ES-MS spectroscopy were used to identify radiolysis products. Two depsides, [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) methyl acetate and [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) ethyl acetate, were the major compounds of kaempferol degradation in methanol and in ethanol, respectively. Other products formed in low concentrations were identified as [4-hydroxyphenyl](oxo) methyl acetate, [4-hydroxyphenyl](oxo) ethyl acetate, and depside [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) acetic acid. The formation of the latter was observed in both solvents. We propose degradation mechanisms that suggest that (.)CH(2)OH and CH(3)(.)CHOH, produced by solvent radiolysis, react with the 3-OH kaempferol group because of its high H-donor capacity. pi-Electron delocalization in the flavonoxy formed after the first H-transfer leads to C-ring opening and consequently to the formation of depsides. G calculation of the degradation products and of (.)CH(2)OH and CH(3)(.)CHOH radicals confirmed the proposed mechanism of kaempferol radiolysis. The rate constants for the reaction between kaempferol and these free radicals were also calculated. Formation of depside has also been observed in many studies of the oxidation of flavonoids; those studying human metabolism have suggested similar redox transformation of flavonols. The antioxidant activities of radiolysis products were evaluated and compared to those of kaempferol.

Cerebral venous thrombosis: clinical outcome and systematic screening of prothrombotic factors

The authors studied 16 consecutive cases of cerebral venous thrombosis (CVT). Clinical outcome was good or excellent in 14 patients. Comprehensive hypercoagulable screening was done at least 3 months after the onset of CVT, including evaluation of genetic coagulation disorders and plasma levels of homocysteine and factor VIII. This screening was positive in 12 patients (75%). An acquired prothrombotic factor was identified in 9 of these 12 patients. Elevation of factor VIII plasma level was the most common coagulation disorder (8 patients).

Radiolysis of kaempferol in water/methanol mixtures. Evaluation of antioxidant activity of kaempferol and products formed

Oxidative reaction between hydroxymethyl radical ((*)CH(2)OH) and kaempferol, in methanol and methanol/water mixtures, was studied by gamma-radiolysis using a (60)Co source. Radiolysis was performed with concentrations and doses ranging from 5 x 10(-)(5) M to 5 x 10(-)(3) M and from 0.5 kGy to 14 kGy, respectively. Kaempferol degradation was followed by HPLC. Results showed that (*)CH(2)OH reacts with kaempferol at the 3-OH group and produces two depsides (K1 and K2) and other products including K3. K1, K2, and K3 were identified by NMR, LC-MS, and HRMS. The kaempferol degradation pathway leading to the K1, K2, and K3 formation is proposed. It was observed that the more water concentration in the irradiation medium increases, the more K2 concentration increases. Comprehension of food preservation is not clear because many phenomena occurring during irradiation are not established. Radiolysis of kaempferol in water/methanol mixtures helps to elucidate the phenomenon and it is possible that during the treatment of nutriments by gamma-irradiation, a series of products such as depside K2 could be formed. Antioxidant properties of kaempferol radiolysis products were evaluated according to their capacity to decrease the EPR DPPH (1,1-diphenyl-2-picrylhydrazil) signal and to inhibit superoxide radicals formed by the enzyme reaction "xanthine + xanthine oxidase".

Redox reactions obtained by gamma irradiation of quercetin methanol solution are similar to in vivo metabolism

The flavonol quercetin is one of the most well-known antioxidant flavonoids. Its antioxidant potential has been studied extensively during the last 10 years, but little is known about the metabolites formed in vivo that lead to the formation of depside and small molecules such as benzoic acids. In this study, gamma irradiation of a quercetin methanol solution was used as a model of certain oxidative reactions that occur in vivo. Qercetin at concentrations ranging from 5 x 10(-5) M to 5 x 10(-3) M, was irradiated with gamma rays at doses of 2-14 kGy. Quercetin degradation was evaluated by HPLC analysis. The major radiolytic metabolite was identified as a depside by NMR and LC-MS. Formation of 3,4-dihydroxybenzoic acid was also observed. The presence of CH3O. formed during methanol radiolysis is invoked to explain depside formation. Transformation of the 8-methoxy substituted depside (Q1) to the 8-hydroxyl substituted depside (Q2) is discussed. The antioxidant properties of quercetin metabolites are evaluated according to their capacity to decrease the EPR DPPH signal and to inhibit superoxide radical formed by the enzymatic reaction (xanthine + xanthine oxidase). For both assays, the IC50 of Q2 is twice as high as that of quercetin.

[Cerebral amyloid angiopathy revealed by transient ischemic events: contribution of MRI to diagnosis and pathophysiology study]

We report the case of a 72-year-old left-handed woman presenting with episodes of paresthesias of the left arm and dysarthria consistent with transient ischemic attacks. The diffusion MRI showed hypersignals of the right corona radiata suggesting recent ischemic process whereas gradient-echo MRI revealed multiple small hypointense regions consistent with petechial hemorrhages restricted to the corticosubcortical regions. Gadolinium-enhanced, T1-weighted MRI showed focal meningeal enhancement. The diagnosis of cerebral amyloid angiopathy was supported by leptomeningeal biopsy. The association of ischemic suffering, petechial haemorrhage and meningeal enhancement as demonstrated by multisequence MRI highly suggest a cerebral amyloid angiopathy.

Baseline magnetic resonance imaging parameters and stroke outcome in patients treated by intravenous tissue plasminogen activator

BACKGROUND AND PURPOSE

We designed a prospective sequential pretreatment and posttreatment MRI study to assess the relation between neuroimaging parameters and clinical outcome in patients treated with intravenous recombinant tissue-type plasminogen activator (rtPA).

METHODS

Patients with symptoms of acute hemispheric ischemic stroke were recruited. The National Institutes of Health Stroke Scale (NIHSS) score was assessed at baseline and at days 1, 7, and 60, and the modified Rankin scale (mRS) at day 60, by which outcome was classified in terms of independence (mRS score 0, 1, or 2) or severe disability or death (mRS score 3 through 6), was assigned. Multimodal stroke MRI was performed at presentation and repeated at day 1. MRI procedures included magnetic resonance angiography, T2* gradient-echo sequence, echoplanar imaging, and isotropic diffusion- (DWI) and perfusion-weighted (PWI) imaging. Patients were treated with intravenous rtPA after MRI completion.

RESULTS

Twenty-nine patients (16 men and 13 women; mean+/-SD age, 65+/-14 years) underwent MRI; the mean time from symptom onset to treatment was 255+/-62 minutes. Twenty-six patients had a vessel occlusion, and 15 patients experienced a partial (Thrombolysis in Myocardial Infarction [TIMI]-2) or total (TIMI-3) recanalization at day 1, whereas 11 patients had a persistent occlusion. Mean NIHSS scores at day 60 were 5.7+/-5.4 if recanalization had occurred and 14+/-2 in cases of persistent occlusion. According to the mRS, 13 patients were independent (mRS 0 through 2), whereas severe disability or death (mRS 3 through 6) was observed in 15 patients. A better outcome was observed when recanalization was achieved (r=-0.68, P=0.0002). PWI volume and time to peak (TTP) within the DWI lesion assessed before therapy were correlated with day-60 NIHSS score (PWI volume: r=0.51, P=0.006, TTP: r=0.35, P=0.07). The day-0 DWI abnormality volume was well correlated with day-60 NIHSS score (r=0.58, P=0.001). Multiple regression linear analysis showed that 2 factors mainly influenced clinical outcome: (1) recanalization, with a high correlation with NIHSS score at day 60 (P=0.0001) and (2) day-0 DWI lesion volume, which is closely associated with day-60 NIHSS score (P=0.03).

CONCLUSIONS

Baseline DWI volume and recanalization are the main factors influencing clinical outcome after rtPA for ischemic stroke.

[Clinical presentation of immune mediated cerebellar ataxia]

Over the last decades, clinical evidence has accumulated indicating that the immune system may play an important role in some central nervous system diseases usually regarded as degenerative. The best known example is paraneoplastic cerebellar ataxia (PCA), which is thought to involve autoimmune cross-reaction between tumor and nervous system antigens. In the past twenty years, several antibodies directed against neuronal and tumor antigens have been described in association with PCA, leading to the description of different subtypes of PCA depending on the associated antibodies, the clinical course and the type of tumor. In some types, cerebellar ataxia occurs alone, whereas, in others, it is only one clinical feature in the setting of extensive nervous system disease. Circulating antibodies have also been described in patients with non-paraneoplastic cerebellar ataxia (N-PCA), suggesting that the immune system may be involved in certain cases of sporadic cerebellar ataxia. In this review, the clinical presentation of the different subtypes of potentially immune-mediated PCA and N-PCA will be described, and the experimental approaches developed in order to understand the pathogenic importance of the immune system in these ataxias will be discussed.

Early detection of cerebral arterial occlusion on magnetic resonance angiography: predictive value of the baseline NIHSS score and impact on neurological outcome

The presence of a thrombus on initial arteriography is directly related to the baseline NIHSS score. Magnetic resonance angiography (MRA) offers a noninvasive and rapid assessment of large cerebral vessel patency. We aimed at evaluating (1) the baseline NIHSS score as a tool for predicting the likelihood of an occluded artery on MRA and (2) the course of stroke within the first week according to the presence of a cerebral arterial occlusion. Patients were enrolled in this prospective study according to the following criteria: (1) acute cerebral ischemia with a neurological deficit lasting >1 h, and (2) brain MRI performed within 24 h of stroke onset. The NIHSS score assessment was performed on admission and at day 1 and day 7. The MRI protocol included: (1) T2-weighted Turbo spin echo, (2) echo-planar imaging isotropic diffusion, (3) T2*-gradient echo sequence, and (4) time of flight MRA (3D TOF Turbo MRA). The presence of a symptomatic cerebral arterial occlusion on MRA was systematically screened. Fifty-four patients were studied. Median age was 60 years. Mean time from stroke onset to NIHSS assessment was 170 +/- 95 min. The mean baseline NIHSS score was 13.5 +/- 7.3. The mean time from stroke onset to MRI was 384 +/- 171 min. MRA was readable in 50 cases. An arterial occlusion was detected in 23 patients (46%). The median baseline NIHSS score was significantly higher in the group of patients with occlusion than in the group of patients without occlusion (18 vs. 7, p = 0.01). The predictive probability to demonstrate an arterial occlusion was related to the baseline NIHSS score. None of the patients with an NIHSS score of 1-6 (11 patients) had visible occlusion, whereas 9 (43%) out of 21 patients with an NIHSS score of 7-15 and 14 (78% ) out of 18 patients with an NIHSS score above 16 had an arterial occlusion. For an increase by one point in the NIHSS score, the odds ratio for the presence of occlusion was 1.28 (95% CI: 1.11-1.46). The course of the stroke as assessed by follow-up NIHSS score was significantly more severe if an occlusion was detected. Median day 0, day 1 and day 7 NIHSS score were, respectively, 18, 16 and 13 in patients who had an occlusion versus 7, 4 and 0 in patients who had no visible occlusion (p < 0.01). A direct relation between the baseline NIHSS score and the likelihood of the presence of an occlusion on initial MRA is demonstrated. The presence of a cerebral arterial occlusion on MRA is significantly linked to a poor neurological outcome.

Radiolysis of quercetin in methanol solution: observation of depside formation

Radiolysis of the flavonol quercetin, a natural antioxidant, was performed in methanol. The degradation process was followed by HPLC analyses. The major product was identified as a depside (Q1) by NMR and LC-MS. The G(Q1) radiolytic factor was plotted versus the initial concentration of quercetin. This radiolytic process was attributed to the CH3O* radicals presented in the irradiated medium. The proposed mechanism invoked a stereospecific oxidation of the 3-hydroxyl group of quercetin which led to C-ring opening and to the formation of the depside Q1. In presence of water, Q1 was transformed into another depside, Q2, by an inverse esterification reaction. A chemical equilibrium was observed between Q1 and Q2. The comprehension of the radiolytic process of quercetin in methanol solution is of importance. Indeed, the same type of oxidative reactions could occur on flavonoids during preservation of food by ionizing radiation.

[Necrosis of a hypophyseal adenoma and ischemic cerebral vascular accident ]

A 78-year old man developed an acute intracranial hypertension followed by central left facial palsy. CT Scan and MRI revealed an ischemia within the right lenticulostriate arteries territory and a hemorrhagic infarction of a pituitary adenoma without extrinsic carotid artery compression. Neuroophthalmologic examination and hormonal screening were normal. Though pituitary apoplexy and stroke might represent a fortuitous association, several mechanisms underlying such clinical picture are advanced.

[Vertebro-basilar ischemic strokes and aseptic meningitis, late complications of Fabry's disease]

Fabry's disease, also called angiokeratoma corporis diffusum universal, is a rare cause of stroke in the young. We report the case of a 39-year-old man who presented with relapsing vertebro-basilar ischemic strokes. Biological tests showed the presence of an aseptic meningitis and a biological inflammatory syndrome, suggesting a particularly progressive illness. The possible mechanisms involved in this exceptional association are discussed.

Old microbleeds are a potential risk factor for cerebral bleeding after ischemic stroke: a gradient-echo T2*-weighted brain MRI study

BACKGROUND AND PURPOSE

T2*-weighted gradient-echo MRI is known to detect old microbleeds (MBs), considered indicative of microangiopathy. MBs might be a potential risk factor for early cerebral bleeding (CB) after ischemic stroke. Therefore, we assessed the impact of MBs on the occurrence of CB after cerebral infarction.

METHODS

We included prospectively stroke patients who had documented ischemic damage. The imaging protocol involved baseline CT scan, T2*-weighted gradient-echo MRI, diffusion-weighted imaging, T2-weighted imaging, and magnetic resonance angiography and had to be performed within 24 hours after symptom onset. The assessment of CB with T2*-weighted gradient-echo sequence necessitated a focal area of signal loss either within the ischemic area revealed by diffusion-weighted imaging or remote from it. Old MBs were defined on T2*-weighted images as homogeneous rounded areas of signal loss without surrounding edema. CT scan was systematically repeated within the first week to verify CB as diagnosed by the T2* weighted sequence.

RESULTS

One hundred patients (mean age, 60 +/- 13 years; range, 19 to 83 years; 58 men, 42 women) met the inclusion criteria. MBs were seen in 20 patients on T2*-weighted imaging. Multivariate logistic regression analysis revealed that age, diabetes, previous use of antithrombotic drugs, evidence of an atherothrombotic source of stroke, and lacunar infarct were significantly associated with MBs (P<0.0001). CB was diagnosed in 26 patients: at the acute stage by T2*-gradient echo sequence in 18 patients and with CT scan performed within the first week in 8 patients. Multivariate logistic regression analysis showed that baseline National Institutes of Health Stroke Scale score, diabetes, and MBs were considered significant and independent predictors of CB (P<0.001).

CONCLUSIONS

Although the pathogenesis of CB after ischemic stroke is multifactorial, the increased observation of CB in patients with MBs suggests that the associated vascular vulnerability contributes to CB.

[Anterior choroidal artery infarction revealing polyarteritis nodosa]

An 81-year old man presented with a sudden right ataxic hemiparesis. Brain CT scan showed a left anterior choroidal artery territory infarction. Biological signs of inflammation were present without any evidence of infection or neoplasm. The patient's clinical status deteriorated with fever, loss of weight and confusion. Muscle biopsy showed characteristic abnormalities of polyarteritis nodosa (PAN). Oral corticosteroids plus monthly pulse intravenous cyclophosphamide were started. A rapid clinical improvement was observed as well as the resolution of inflammation within one month. Twenty months later, the patient had recovered normal cognitive function and was able to carry out all usual activities. We describe the CNS complications of PAN and the therapeutic options.

Thrombolytic therapy in acute ischemic stroke patients with cardiac thrombus

The authors describe the outcome of five patients with a cardiac thrombus selected among 183 patients with stroke (2.7 %) who were given IV tissue plasminogen activator (tPA). No early systemic or cerebral embolism occurred. Two patients made a complete recovery at 3 months. Two patients had a moderate outcome. One patient had late recurrent cerebral embolism and died. These data suggest that the presence of a cardiac thrombus is not associated with a high risk of recurrent embolism in patients with stroke who are given IV tPA.