Repetitive transcranial magnetic stimulation at 1Hz and 5Hz produces sustained improvement in motor function and disability after ischaemic stroke.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) is a simple and non-invasive method of augmenting motor recovery after stroke, probably mediated by restoring inter-hemispheric activation balance. This placebo-controlled pilot study examined the possible benefit of stimulating the lesioned hemisphere (5-Hz rTMS) or inhibiting the contra-lesional hemisphere (1-Hz rTMS) on clinical recovery of motor function in patients with ischaemic stroke and assessed the sustainability of the response. METHODS: Sixty patients with ischaemic stroke (>1 month from onset) with mild-to-moderate hemiparesis were randomized to receive 10 daily sessions of either sham rTMS, 5-Hz ipsi-lesional rTMS or 1-Hz contra-lesional rTMS, in addition to a standard physical therapy protocol. Serial assessments were made over a period of 12 weeks by the thumb-index finger tapping test (FT), Activity Index (AI) score and the modified Rankin Scale (mRS). RESULTS: In contrast to control patients, those receiving active rTMS as ipsi-lesional 5-Hz stimulation or 1-Hz contra-lesional stimulation showed statistically significant improvement on the FT test, AI scores and mRS score at 2 weeks, and the effect was sustained over the 12-week observation period. No significant adverse events were observed during treatment in either group. CONCLUSIONS: Repetitive TMS has beneficial effects on motor recovery that can be translated to clinically meaningful improvement in disability in patients with post-stroke hemiparesis, with a well-sustained effect. The similarity of inhibitory and stimulatory rTMS in producing these effects supports the inter-hemispheric balance hypothesis and encourages further research into their use in long-term neurorehabilitation programmes of patients with stroke.

T2*-weighted MRI versus oxygen extraction fraction PET in acute stroke.

BACKGROUND: Mapping high oxygen extraction fraction (OEF) in acute stroke is of considerable interest to depict the at-risk tissue. Being sensitive to deoxyhemoglobin, T2*-weighted MRI has been suggested as a potential marker of high OEF. METHODS: We compared T2*-weighted images from pre-contrast arrival perfusion scans against quantitative positron emission tomography in 5 patients studied 7-21 h after onset of carotid territory stroke. OEF and T2* signal were obtained in the voxels with significantly high OEF. RESULTS: All patients showed increased OEF. No significant relationship between OEF and T2*-weighted signal was found either within or between subjects. CONCLUSION: We found no indication that T2*-weighted MRI in the way implemented in this investigation was sensitive to high OEF in acute stroke.

Pathophysiology of ischaemic stroke: insights from imaging, and implications for therapy and drug discovery.

Preventing death and limiting handicap from ischaemic stroke are major goals that can be achieved only if the pathophysiology of infarct expansion is properly understood. Primate studies showed that following occlusion of the middle cerebral artery (MCA)--the most frequent and prototypical stroke, local tissue fate depends on the severity of hypoperfusion and duration of occlusion, with a fraction of the MCA territory being initially in a 'penumbral' state. Physiological quantitative PET imaging has translated this knowledge in man and revealed the presence of considerable pathophysiological heterogeneity from patient to patient, largely unpredictable from elapsed time since onset or clinical deficit. While these observations underpinned key trials of thrombolysis, they also indicate that only patients who are likely to benefit should be exposed to its risks. Accordingly, imaging-based diagnosis is rapidly becoming an essential component of stroke assessment, replacing the clock by individually customized management. Diffusion- and perfusion-weighted MR (DWI-PWI) and CT-based perfusion imaging are increasingly being used to implement this, and are undergoing formal validation against PET. Beyond thrombolysis per se, knowledge of the individual pathophysiology also guides management of variables like blood pressure, blood glucose and oxygen saturation, which can otherwise precipitate the penumbra into the core, and the oligaemic tissue into the penumbra. We propose that future therapeutic trials use physiological imaging to select the patient category that best matches the drug's presumed mode of action, rather than lumping together patients with entirely different pathophysiological patterns in so-called 'large trials', which have all failed so far.

Call-Fleming syndrome associated with subarachnoid haemorrhage: three new cases.

BACKGROUND: The Call-Fleming syndrome (CFS) comprises acute severe recurrent (thunderclap) headaches, occasional transient or fluctuating neurological abnormalities and reversible segmental cerebral vasoconstriction. It is a benign condition with an excellent prognosis, yet because it is often clinically and radiologically similar to a number of commonly encountered conditions, diagnostic difficulties may arise, leading to inappropriate, and even potentially harmful, investigative and therapeutic approaches. CASES: Three personal cases are presented to highlight the occurrence of subarachnoid haemorrhage (SAH) as part of CFS. In two patients with a positive CT head, SAH involved the sulci in the upper cerebral convexity, an unusual location in aneurysmal SAH. RESULTS: SAH is not an uncommon feature of CFS, occurring in approximately 25% of reported cases, and may pose a diagnostic challenge. CFS has a relatively characteristic spectrum of features, allowing a confident diagnosis in most cases, even when atypical features such as SAH are present. CONCLUSIONS: Recognising the spectrum of abnormalities seen in CFS, including particularly SAH, allows a sound approach to a safe diagnosis.

Combined PET-FDG and USPIO-enhanced MR imaging in patients with symptomatic moderate carotid artery stenosis.

INTRODUCTION: PET-FDG and USPIO-enhanced MRI are increasingly being used in depicting carotid atheroma inflammation--a risk factor for the high risk plaque. Their combined use has not been previously reported. REPORT: Two patients presenting with stroke and identified with 50% carotid stenosis on duplex ultrasonography, underwent PET FDG and USPIO-enhanced MR imaging. Results were concordant and complementary suggesting that both techniques reflect similar metabolic processes. DISCUSSION: The selection of patients for carotid revascularisation has largely been based on the severity of luminal stenosis alone. The two imaging modalities, which identify inflammatory activity, may be potential surrogate risk markers in the selection of patients eligible for carotid surgery, if plaque inflammation can be correlated with risk of developing clinical symptoms.

Call-Fleming syndrome associated with subarachnoid haemorrhage: three new cases.

The Call-Fleming syndrome (CFS) comprises acute severe recurrent (thunderclap) headaches, occasional transient or fluctuating neurological abnormalities and reversible segmental cerebral vasoconstriction. It is a benign condition with an excellent prognosis, yet because it is often clinically and radiologically similar to a number of commonly encountered conditions, diagnostic difficulties may arise, leading to inappropriate, and even potentially harmful, investigative and therapeutic approaches. Three personal cases are presented to highlight the occurrence of subarachnoid haemorrhage (SAH) as part of CFS. In two patients with a positive CT head, SAH involved the sulci in the upper cerebral convexity, an unusual location in aneurysmal SAH. SAH is not an uncommon feature of CFS, occurring in approximately 25% of reported cases, and may pose a diagnostic challenge. CFS has a relatively characteristic spectrum of features, allowing a confident diagnosis in most cases, even when atypical features such as SAH are present. Recognising the spectrum of abnormalities seen in CFS, including particularly SAH, allows a sound approach to a safe diagnosis.