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Digital Medical Imaging Fundamentals and Medical Image File Formats

MRI

________- Corresponds to the MR signal response of the tissue.

Digitizer

________- represents the optical density of the small square area of the film.

voxel

If the digital image is 3D, then the picture element is called a

Computed Tomography

Represents the relative linear attenuation coefficient of the tissue.

Ultrasound

Echo signal of the utz beam when it penetrates the tissues.

intensity value and location address

Each pixel has an- intensity value and location address.

Penetrometer

________- is a device used to make gray levels.

Gray levels

________- represent physical, chemical, & physiological properties of the state of anatomical structures or physiological processes when the image was captured.

Radiolucent

________- is dark or black.

pixel

Each element of the 2D array is a

Matrix

________- is a rectangular arrangement of numbers into rows and columns.

image

A(n) ________- is a two dimensional function.

intensity value and location address

Each pixel has an

An image

is a two dimensional function

A digital image

is a 2D representation

pixel

Each element of the 2D array is a

voxel

If the digital image is 3D, then the picture element is called a

Matrix

is a rectangular arrangement of numbers into rows and columns

DIGITIZED

if the image is obtained through a digitizer

DIGITAL IMAGES

if it is generated digitally

Gray levels

represent physical, chemical, & physiological properties of the state of anatomical structures or physiological processes when the image was captured

penetrometer

is a device used to make gray levels

radiolucent

is dark or black

radiopaque

is white

Digitizer

represents the optical density of the small square area of the film

Computed Tomography

Represents the relative linear attenuation coefficient of the tissue

Water

0

Air

(-1000)

Bone

1000

MRI

Corresponds to the MR signal response of the tissue

Ultrasound

Echo signal of the utz beam when it penetrates the tissues

Image File Format

Provide a standardized way to store the information describing an image in a computer file

8 bit

0 - 255

9 bit

0 - 511

10 bit

0 - 1023

11 bit

0 - 2045

12 bit

0 - 4095

Spatial Resolution, Density Resolution, Signal - to - noise Ratio

Quality of a digital image, is measured by three parameters:

Imaging Modality
Acquisition Protocol
Reconstruction
Post-processing

Numerical value of a pixel depends on the? (4)

Pixel Depth

Number of bits used to encode the information of each pixel

Color Depth

amount of information per pixel

Monochrome

1 bit of information per pixel

Grey scale

8 bits of information per pixel

Color (RGB)

8 or 16 bits of information per pixel

True Color (RGB)

24 or 32 bits of information per pixel

Photometric Interpretation

Specifies how the pixel data should be interpreted for the correct image display as a monochrome or color image

x-ray, CT, MRI

Grayscale photometric interpretation (3)

Nuclear Medicine, SPECT, PET

Color map or color palette/LUT

Metadata

Information that describes the image

Pixel data

Numerical values of the pixels are stored

DICOM
Analyze, Nifti, Minc

2 categories for Medical Image File Formats

.img
.hdr

extension of Analyze

.nii

extension of Nifti

.mnc

extension of Minc

.dcm

extension of DICOM