Friday, May 23, 2014

MRI vs Cat scan.....?




lilkay


my docter says i need an MRI but i would rather not get that..

is a cat scan possible to get instead?
can a cat scan show muscles and nerves?



Answer
MRI

Magnetic Resonance Imaging (MRI), or nuclear magnetic resonance imaging (NMRI), is primarily a medical imaging technique most commonly used in radiology to visualize the internal structure and function of the body. MRI provides much greater contrast between the different soft tissues of the body than computed tomography (CT) does, making it especially useful in neurological (brain), musculoskeletal, cardiovascular, and oncological (cancer) imaging. Unlike CT, it uses no ionizing radiation, but uses a powerful magnetic field to align the nuclear magnetization of (usually) hydrogen atoms in water in the body. Radio frequency (RF) fields are used to systematically alter the alignment of this magnetization, causing the hydrogen nuclei to produce a rotating magnetic field detectable by the scanner. This signal can be manipulated by additional magnetic fields to build up enough information to construct an image of the body.[1]:36

CAT scan

Computed tomography (CT) is a medical imaging method employing tomography. Digital geometry processing is used to generate a three-dimensional image of the inside of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation. The word "tomography" is derived from the Greek tomos (slice) and graphein (to write). Computed tomography was originally known as the "EMI scan" as it was developed at a research branch of EMI, a company best known today for its music and recording business. It was later known as computed axial tomography (CAT or CT scan) and body section röntgenography.

CT produces a volume of data which can be manipulated, through a process known as "windowing", in order to demonstrate various bodily structures based on their ability to block the X-ray/Röntgen beam. Although historically the images generated were in the axial or transverse plane, orthogonal to the long axis of the body, modern scanners allow this volume of data to be reformatted in various planes or even as volumetric (3D) representations of structures. Although most common in medicine, CT is also used in other fields, such as nondestructive materials testing. Another example is the DigiMorph project at the University of Texas at Austin which uses a CT scanner to study biological and paleontological specimens.

you can find out more on wikipedia, that is where i got this. or just go ask your doctor. but i would say you could do either, depending on what your insurance covers and how much you are will/able to pay.

How far is the automated 3-D segmentation of Brain MRI efficient compared to manual segmentation?




Sandhya


We are doing a project on automated 3-D segmentation of brain MRI using MATLAB. We would like to know the extent to which "Surf" commands are efficient in producing reliable segmented 3-D image. The accuracy level, how much it is better compared to manual segmentation. We need statistical detail, kindly help us....


Answer
This correspondence deals with the development of an
automated 3-D segmentation of Brain MRI. The proposal is a
model-based approach for accurate, robust, and automated
tissue segmentation of brain MRI data of single as well as
multiple magnetic resonance sequences. The main contribution
of this study is that we employ an edge-based geodesic active
contour for the segmentation task by integrating both image
edge geometry and voxel statistical homogeneity into a novel
hybrid geometricâstatistical feature to regularize contour
convergence and extract complex anatomical structures. We
validate the accuracy of the segmentation results on simulated
brain MRI scans of both single T1-weighted and multiple T1/
T2/PD-weighted sequences. When compared to a current stateof-
the-art region based level-set segmentation formulation,
our white matter and gray matter segmentation resulted in
significantly higher accuracy levels with a mean improvement
in Dice similarity indexes. Thus the development of the project
is done using MATLAB simulation for results.
A Hybrid Automated 3D Segmentation in Brain MRI -------------------------------------------------------- Advantages of a MRI scan
⢠MRI scanners are good at looking at the non-bony parts
or "soft tissues" of the body. In particular, the brain, spinal
cord and nerves are seen much more clearly with MRI
than with regular x-rays and CAT scans.
⢠Also, muscles, ligaments and tendons are seen quite well
so that MRI scans are commonly used to look at knees
and shoulders following injuries.
⢠A MRI scanner uses no x-rays or other radiation.
⢠A disadvantage of MRI is itâs higher cost compared to a
regular x-ray or CAT scan. Also, CAT scans are frequently
better at looking at the bones that MRI.




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