Anatomical imaging Week 1

What do bones and calcified structures show on plain radiograph?

have the highest density and therefore with absorb the most xrays to produce a radiopaque (white) shadow on the film

What do soft tissues show on a plain radiograph?

almost transparent to hard xrays having a lower density than bone which produces a semi-radiopaque (grey) appearance

What does fat show on a plain radiograph?

fat absorbs slightly fewer xrays than most soft soft tissues and therefore appears more radiolucent (blacker) than the other soft tissues

What does air show on a plain radiograph?

air has the lowest density with the least xrays absorbed and has a radiolucent (black) appearance in plain films

What is superimposition?

all the structures along the path of the beam are projected onto the same portion of the film

What does side-on mean?

-the structure is orientated perpendicular to the xray beam -true length due to minimal superimposition on itself

What is end-on?

-the structure is orientated parallel to the xray beam -displays significant superimposition on itself and length and/or size is highly distorted

What is foreshortened?

-if the structure is orientated oblique to the xray beam -the length on the film appears shorter than its true length due to some superimposition on itself

What is plain radiograph?

-xrays need to pass through the body to reach the cray film/receptor -the denser the tissue, the less xrays are able to pass through resulting in a black or radiopaque appearance -converted to a negative image, converting black structures to white and white structures to black

What is a computed tomography (CT)?

-captures images of body by rotating around the body forming slice data on a computer that can be 3D -can focus on bone windows in more dense structures -can focus on mediastinal, abdominal or brain window in less dense structures

What is Magnetic Resonance Imaging (MRI)?

uses a magnetic field to create images based on the hydrogen atoms within the tissues of the body spinning within the magnetic field

What is an angiogram?

-contrast introduced into blood vessels intravenously or direct arterial puncture -the contrast will circulate the cardiovascular system until excreted by the kidneys -as the contrast moves through major organs it is taken up into the tissues of these organs to increase the radiodensity of these organs too, therefore able to visualise blood vessels but also the major visceral organs or the thorax and abdomen

What is barium meal or enema?

contrast introduced into the digestive system

What is a urography?

contrast introduced into the urinary system

What are sesamoid bones?

-sesamoid shaped bones found in the hand -3 constant, pisiform and 2 in the head of the 1st metacarpal bone