Demyelinating Disease 911 Multiple Sclerosis
T2-weighted and fluid-attenuated inversion-recovery FLAIR images are sensitive for depicting focal lesions in patients with multiple sclerosis MS , but lack histopathologic specificity. Other lesions such as inflammation, edema, demyelination, remyelination, reactive gliosis and axonal loss have an MR appearance similar to MS lesions and can often not be distinguished from MS 1 . Hypointense T1 lesions in MS are usually caused by matrix destruction and loss of axons 2 . These lesions, which are...
Systemic Lupus Erythematosus
Involvement of the CNS occurs in 14-75 of patients with systemic lupus erythematosus SLE 4 . Pathologically, microinfarcts and small vessel vasculopathy are the most common. Vasculopathy affects predominantly the arterioles and capillaries, resulting in vessel tortuosity, vascular hyalinization, endothelial proliferation and perivascular inflammation or gliosis. Spectrum of CNS vasculopathy. Modified from 10 Systemic lupus erythematosus in a 39-year-old woman with recurrent episodes of stroke,...
Early Subacute Hematoma
In the early stage of the subacute hematoma Figs. 6.2 and 6.3 , there is a decline in the energy state of the red blood cell and hemoglobin is oxidized to met-he-moglobin 3,4,7,10,11,14,19,22,23,28-30, 33, 34 . In met-hemoglobin the iron is still bound to the heme moiety within the globin protein, but it is now in the ferric state with five unpaired electrons. This transformation normally starts in the periphery of the hemorrhage and gradually evolves to the center. In the transition to...
Vasogenic Edema
Vasogenic edema is characterized by dysfunction of the blood-brain barrier, allowing an abnormal passage of proteins, electrolytes and water into the extracellular compartments. Fluid leaving the capillaries enlarges the extracellular space, predominantly in the white matter. Osmotic and hydrostatic gradients will also cause interstitial edema, increasing the extracellular space as water shifts from blood vessels and or ventricles. Intracellular components are rela tively preserved Fig. 4.14 ,...
Hypoxic Ischemic Encephalopathy
Excitotoxic mechanisms in the neuron and astrocyte. In the neuron, glutamate is released from the pre-synaptic terminal into the synaptic cleft. The glutamate binding to NMDA receptors allows entry of Ca2 into the postsynaptic neuron, which can result in necrotic cell death or apoptosis. The glutamate binding to non-NMDA receptors allows entry of Na into the post-synaptic neuron, resulting in cytotoxic edema of the neuron. Re-uptake of extracellular glutamate takes place at the pre-synaptic...
Shielded Gradients. And The General Solution To The Near Field Problem Of Electromagnet Design
Normal adult brain of a 40-year-old male without neurological deficits.a Isotropic DW image is obtained by combining b0 image and three orthogonal unidirectional images x,y,z axis .The bilateral globi pallidi have low signal on DW image as a result of physiological iron deposition arrows . Corticospinal tracts have mildly high signal on DW image arrowheads . Gray matter shows mildly high signal compared to white matter.These signal changes on isotropic DW imaging are normal and are caused by T2...
