Modern Magnetic Resonance Techniques Research Articles

MR Imaging of Multiple Sclerosis

Owing to its ability to depict the pathologic features of multiple sclerosis (MS) in exquisite detail, conventional magnetic resonance (MR) imaging has become an established tool in the diagnosis of this disease and in monitoring its evolution. MR imaging has been formally included in the diagnostic work-up of patients who present with a clinically isolated syndrome suggestive of MS, and ad hoc diagnostic criteria have been proposed and are updated on a regular basis. In patients with established MS and in those participating in treatment trials, examinations performed with conventional MR pulse sequences provide objective measures to monitor disease activity and progression; however, they have a limited prognostic role. This has driven the application of newer MR imaging technologies, including higher-field-strength MR units, to estimate overall MS burden and mechanisms of recovery in patients at different stages of the disease. These techniques have allowed in vivo assessment of the heterogeneity of MS pathologic features in focal lesions and in normal-appearing tissues. More recently, some of the finer details of MS, including macrophage infiltration and abnormal iron deposition, have become quantifiable with MR imaging. The utility of these modern MR techniques in clinical trial monitoring and in the assessment of the individual patient's response to treatment still need to be evaluated.

Modern progress in hepatic encephalopathy

Sir, We read with interest the article by Cash et al. 1 reviewing the pathophysiology and management of hepatic encephalopathy (HE). We agree that this condition is understudied and sub-optimally treated, but would suggest that the following points are considered. First, we would suggest that in contrast to the conclusions of the authors, recent research has provided invaluable insight into the cellular pathophysiology of HE. Modern magnetic resonance techniques have confirmed increased brain water content in patients with HE,2 highlighting the importance of the astrocyte-swelling hypothesis and other well-described pathophysiological mechanisms.3 While increased intra-astrocytic glutamine accumulation, driven by ambient …

Pathophysiology of Cerebral Small Vessels in Vascular Cognitive Impairment

Cerebral small-vessel alterations play a central role in determining lesions of subcortical structures and eventually may lead to cognitive impairment. Small-vessel diseases are classified according to the pathological viewpoint. The most important ones are the changes in small arteries and arterioles caused by prolonged hypertension. These small-vessel changes may result in ischemic damage to the brain parenchyma and blood-barrier alterations. Both mechanisms are thought to contribute to the occurrence of white-matter changes and lacunar infarcts. Modern magnetic resonance techniques such as diffusion, perfusion, and spectroscopy may allow the in vivo study of the pathophysiology of small-vessel diseases and the consequences on the brain parenchyma.