CT and MRI Scans in Neurological Practice: A Quick Overview

Written by Gary Cordingley

Before computed tomographic (CT) scans became available inrepparttar 1970s, there was no good method for imagingrepparttar 148662 brain. The available methods and technologies struck aroundrepparttar 148663 target without quite hittingrepparttar 148664 bull's-eye.

We had skull x-rays which imagedrepparttar 148665 bony brain-case, but notrepparttar 148666 brain itself. We had arteriograms which imagedrepparttar 148667 insides of blood-vessels supplyingrepparttar 148668 brain. We had nuclear brain scans which imaged chunks of brain that were recently damaged. We had a particularly nasty test called a pneumoencephalogram (PEG) in whichrepparttar 148669 doctor squirted air through a spinal tap needle and encouraged it to bubble around and insiderepparttar 148670 brain by turningrepparttar 148671 patient every which-a-way—including upside-down—while x-ray pictures showed whererepparttar 148672 air could and couldn't go. Finally,repparttar 148673 most accurate method was not a physical picture at all, but a mind's-eye picture withinrepparttar 148674 brain of an examining neurologist. Yet diagnoses still got made and patients did get treated.

CT scans revolutionizedrepparttar 148675 practice of neurology. It's not thatrepparttar 148676 other methods disappeared (well, yes, PEGs thankfully did disappear) but that CT scans vastly improvedrepparttar 148677 accuracy of diagnosis and treatment. Even when CT scans didn't showrepparttar 148678 disease itself (e.g. multiple sclerosis or a fresh stroke) they assistedrepparttar 148679 diagnostic process by provingrepparttar 148680 absence of a brain tumor, abscess or hemorrhage that were also onrepparttar 148681 list of diagnostic possibilities.

CT scans did (and still do) this by sending x-ray beams throughrepparttar 148682 head at various angles and collectingrepparttar 148683 x-ray beams onrepparttar 148684 opposite side that were not absorbed byrepparttar 148685 head. Then magic occurs. A series of images appear on a computer monitor or on x-ray film as ifrepparttar 148686 head had been run through a giant salami-cutter andrepparttar 148687 slices were laid out flat and in sequence.

On CT picturesrepparttar 148688 different parts ofrepparttar 148689 head are displayed in various shades of gray according to how much they absorb x-rays. The skull-bone absorbs x-raysrepparttar 148690 most and shows asrepparttar 148691 whitest component. Atrepparttar 148692 other end ofrepparttar 148693 gray-scale,repparttar 148694 watery spaces in and aroundrepparttar 148695 brain absorb x-raysrepparttar 148696 least and show asrepparttar 148697 blackest components. The brain itself is somewhere in between, showing up inrepparttar 148698 mid-gray range. Abnormal components, like brain tumors and blood-collections, are identified not just by appearing in their own shades of gray, but also by their locations and shapes. Creating a second set of slices afterrepparttar 148699 patient receives an infusion of intravenous dye provides an additional dimension to imaging not unlike that provided byrepparttar 148700 older, nuclear scans.

Then inrepparttar 148701 1980s magnetic resonance imaging (MRI) scans burst uponrepparttar 148702 scene and astonishedrepparttar 148703 medical community by not just imagingrepparttar 148704 brain itself, but by doing so in a brand-new way. Instead of imagingrepparttar 148705 extent to whichrepparttar 148706 head's different components absorb x-rays, MRIs instead focus on water-molecules. To be more precise, MRIs imagerepparttar 148707 rate at which spinning hydrogen-atoms of water molecules within different parts ofrepparttar 148708 brain either line-up or fall out or alignment with a strong magnetic field. These differing rates of magnetization or de-magnetization are fed into a computer. Then magic occurs yet again. A series of slice-like images is created and displayed on a computer-screen or x-ray-type film in shades of gray. Abnormal structures, like brain-tumors orrepparttar 148709 plaques of multiple sclerosis, are displayed in their own shades of gray and are also recognizable by their shapes and locations. Obtaining another set of images after intravenous administration of gadolinium—the MRI equivalent of x-ray dye—also adds diagnostic information.

My best makeup beauty tips

Written by Yasiv Marin

1) Never wash your face with soap. Soap contains an astrigent that strips away moisture, therefore damages your skin eventually.

2) Always cleanse, tone and moisturize. Milky cleansers are best to use (eg. Marcelle Cleansing milk).

3) Never squeeze pimples, if you find that you're getting lots of them, forget about overrepparttar counter products.....they won't work on you, they only work on people that get a zit once in a blue moon. Instead, get to a dermatologist as soon as possible and you're skin will be clear in no time. Trust me, I used to have severe acne, I saw a dermatologist, 4 months later my face was smooth as a baby's butt and it still is.

4) Apply a yellow-toned concealer under dark circles and anywhere you might see imperfections. Next, apply foundation with a sponge, blend smoothly and make sure it matches your skintone!!! So many girls now a days look like they're wearing masks and that's because they're not choosingrepparttar 148661 right color for their skin.

5) Powder your face with a translucent powder and use a nice, big, soft, puffy brush (my favorite brushes are QUO brand). Powdering will take shine off of your face and easerepparttar 148662 application of blush.

Cont'd on page 2 ==>
ImproveHomeLife.com © 2005
Terms of Use