From micro‐ to macro‐structures in multiple sclerosis: what is the added value of diffusion imaging

Diffusion imaging has been instrumental in understanding damage to the central nervous system as a result of its sensitivity to microstructural changes. Clinical applications of diffusion imaging have grown exponentially over the past couple of decades in many neurological and neurodegenerative diseases, such as multiple sclerosis (MS). For several reasons, MS has been extensively researched using advanced neuroimaging techniques, which makes it an ‘example disease’ to illustrate the potential of diffusion imaging for clinical applications. In addition, MS pathology is characterized by several key processes competing with each other, such as inflammation, demyelination, remyelination, gliosis and axonal loss, enabling the specificity of diffusion to be challenged. In this review, we describe how diffusion imaging can be exploited to investigate micro‐, meso‐ and macro‐scale properties of the brain structure and discuss how they are affected by different pathological substrates. Conclusions from the literature are that larger studies are needed to confirm the exciting results from initial investigations before current trends in diffusion imaging can be translated to the neurology clinic. Also, for a comprehensive understanding of pathological processes, it is essential to take a multiple‐level approach, in which information at the micro‐, meso‐ and macroscopic scales is fully integrated

Endovascular mechanical thrombectomy for the treatment of acute ischemic stroke due to arterial dissection.

Arterial dissections account for 2% of strokes in all age groups, and up to 25% in patients aged 45 years or younger. The safety of endovascular intervention in this patient population is not well characterized. We identified all patients in the Merci registry - a prospective, multi-center post-market database enrolling patients treated with the Merci Retriever thrombectomy device - with arterial dissection as the most likely stroke etiology. Stroke presentation and procedural details were obtained prospectively; data regarding procedural complications, intracerebral hemorrhage (ICH), and the use of stenting of the dissected artery were obtained retrospectively. Of 980 patients in the registry, ten were identified with arterial dissection (8/10 ICA; 2/10 vertebrobasilar). The median age was 48 years with a baseline NIH stroke scale score of 16 and median time to treatment of 4.9 h. The procedure resulted in thrombolysis in cerebral ischemia (TICI) scores of 2a or better in eight out of ten and TICI 2b or better in six out of ten patients. Stenting of the dissection was performed in four of nine (44%). The single complication (1/9; 11%) - extension of a dissected carotid artery - was treated effectively with stenting. No symptomatic ICH or stroke in a previously unaffected territory occurred. A favorable functional outcome was observed in eight out of ten patients. Despite severe strokes on presentation, high rates of recanalization (8/10) and favorable functional outcomes (8/10) were observed. These results suggest that mechanical thrombectomy in patients with acute stroke resulting from arterial dissection is feasible, safe, and may be associated with favorable functional outcomes

Increased pelvic vein thrombi in cryptogenic stroke: results of the Paradoxical Emboli from Large Veins in Ischemic Stroke (PELVIS) study.

Cryptogenic stroke is associated with an increased prevalence of patent foramen ovale. The Paradoxical Emboli From Large Veins in Ischemic Stroke (PELVIS) study hypothesized that patients with cryptogenic stroke have an increased prevalence of pelvic deep venous thrombosis (DVT).At 5 sites, patients 18 to 60 years of age received an MRI venogram (MRV) of the pelvis within 72 hours of new symptom onset. Clinical data were then determined. Radiologists blinded to clinical data later read the scans.The 95 patients who met entry criteria were scanned. Their mean+/-SD age was 46+/-10 years, and time from stroke onset to pelvic MRV scan was 49+/-16 hours. Compared with those with stroke of determined origin (n=49), patients with cryptogenic stroke (n=46) were significantly younger, had a higher prevalence of patent foramen ovale (61% versus 19%), and had less atherosclerosis risk factors. Cryptogenic patients had more MRV scans with a high probability for pelvic DVT (20%) than patients with stroke of determined origin (4%, P<0.03), with most having an appearance of a chronic DVT.In this study of young stroke patients evaluated early after stroke, patients with cryptogenic stroke showed differences in several clinical features compared with patients with stroke of determined origin, including increased prevalence of pelvic DVT. The results require confirmation but suggest that paradoxical embolus from the pelvic veins may be the cause of stroke in a subset of patients classified as having cryptogenic stroke

Increased Pelvic Vein Thrombi in Cryptogenic Stroke

Background and Purpose— Cryptogenic stroke is associated with an increased prevalence of patent foramen ovale. The Paradoxical Emboli From Large Veins in Ischemic Stroke (PELVIS) study hypothesized that patients with cryptogenic stroke have an increased prevalence of pelvic deep venous thrombosis (DVT). Methods— At 5 sites, patients 18 to 60 years of age received an MRI venogram (MRV) of the pelvis within 72 hours of new symptom onset. Clinical data were then determined. Radiologists blinded to clinical data later read the scans. Results— The 95 patients who met entry criteria were scanned. Their mean±SD age was 46±10 years, and time from stroke onset to pelvic MRV scan was 49±16 hours. Compared with those with stroke of determined origin (n=49), patients with cryptogenic stroke (n=46) were significantly younger, had a higher prevalence of patent foramen ovale (61% versus 19%), and had less atherosclerosis risk factors. Cryptogenic patients had more MRV scans with a high probability for pelvic DVT (20%) than patients with stroke of determined origin (4%, P Conclusions— In this study of young stroke patients evaluated early after stroke, patients with cryptogenic stroke showed differences in several clinical features compared with patients with stroke of determined origin, including increased prevalence of pelvic DVT. The results require confirmation but suggest that paradoxical embolus from the pelvic veins may be the cause of stroke in a subset of patients classified as having cryptogenic stroke