D's

Question 1

dacryocystorhinography

Answer 1

A radiographic contrast study of the nasolacrimal duct.

Question 2

decubitus

Answer 2

Position assumed when lying down. Opposed to erect or standing.

Question 3

degenerative joint disease (DJD)

Answer 3

The most common joint disorder in dogs and cats, characterized by degradation of articular cartilage and subchondral bone (also called osteoarthritis and osteoarthrosis). May result from trauma,

infection, age-related wear, overuse, developmental anomalies,

immune-mediated disease, and other causes. The most

common radiographic sign is osteophyte formation.

Question 4

definition

Answer 4

Refers to the margination of a lesion and is affected by the degree of activity and aggressiveness of a disease process. Definition should not be confused with (1) detail, which is affected by technical factors, (2) shape, which may be smooth or irregular, or (3) opacity interfaces, which are affected by patient’s body condition, presence of effusion, etc.

Examples:

• A well-defined periosteal response is inactive; an illdefined

periosteal response is active.

• Well-defined osteolysis is less aggressive; ill-defined osteolysis

is more aggressive.

• A well-defined pulmonary nodule is more likely to be a

tumor; an ill-defined lung nodule is more typical of an

abscess or mycotic granuloma.

Question 5

discography

Answer 5

A radiographic contrast study of the central portion of an intervertebral disc.

Question 6

discospondylitis

Answer 6

Inflammation or infection of an intervertebral disc (other names: intradiscal osteomyelitis, diskitis).

Question 7

disseminated idiopathic skeletal hyperostosis (DISH)

Answer 7

Flowing mineralization along contiguous vertebral

bodies. DISH resembles severe spondylosis deformans.

Other names: Forestier’s disease (human medical term).

distal: Away from the center of the body. Opposed to proximal (Figure 2.22).

Question 8

distortion

Answer 8

(1) Geometric distortion occurs when one part of the patient (subject or object) is positioned further from the detector than other parts, creating uneven magnification.
(2) Positional distortion refers to errors in positioning, such as rotation of the sternum on a ventrodorsal radiograph or placing a structure of interest at the periphery of the field of view, which can falsely alter the normal appearance.

Question 9

diverticulum

Answer 9

A pouch or sac extending outward from a hollow organ or structure (e.g. stomach, intestine, esophagus, urinary bladder).

Question 10

donut sign

Answer 10

Refers to the end-on visualization of a bronchus with a thickened wall, increased endobronchial secretions,

or peribronchial infiltrate. Characteristic of a bronchial

pulmonary pattern.

Question 11

dolichocephalic

Answer 11

Refers to the shape of a skull in which the nasal cavity is longer than the cranium. The occipital crest tends to be prominent in animals with this type of skull. Examples: Collie, Greyhound.

Question 12

dorsal

Answer 12

Toward the back or spine. Opposed to ventral. Also

refers to the top, front, or extensor surface of limbs (at or

below the carpus and tarsus) and the top of the head (Figure

2.22).

Question 13

dorsal recumbency

Answer 13

Animal is positioned lying on its back

Question 14

dorsopalmar/plantar

Answer 14

Describes the path of the x-ray beam (x-rays enter the dorsum of the limb and exit the palmar/plantar surface).

Question 15

dorsoventral (DV) radiograph

Answer 15

The x-ray beam enters the dorsal surface of a body part and exits the ventral surface

Question 16

Dose

Answer 16

The recommended quantity of an agent required for therapy or a specific procedure

Question 17

double contrast

Answer 17

A radiographic contrast study using negative (e.g., gas) and positive contrast media (e.g., barium, iodinated agents).

Question 18

double physis sign

Answer 18

Refers to the line of decreased opacity within the metaphysis parallel to the physis in animals suffering from hypertrophic osteodystrophy.

Question 19

delayed union fracture

Answer 19

The bone fragments do not unite within the expected period of time, but healing is believed to eventually occur.

Question 20

density

Answer 20

Radiographic density refers to the degree of blackening of a radiograph. Physical density refers to the characteristic of a material to block x-rays. Previously, the term density was used synonymously with opacity. Density is stillused to describe opacity on CT images

Question 21

detail

Answer 21

Refers to the edge sharpness of structures as seen on a radiograph. Detail is affected by technical factors such

as exposure settings, motion artifact, type of film:screen

system, focal spot size, etc. It is one of the four quality characteristics of a radiograph (density, detail, distortion, contrast). Detail has nothing to do with the patient and everything to do with how the radiograph was created.

Detail should not be confused with (1) definition, which is

affected by activity and aggressiveness of a disease process

or (2) opacity interfaces, which are affected by patient’s body

condition, presence of effusion, etc. Detail is enhanced by

using a small focal spot, tight collimation, larger distance

between focal spot and detector, and a shorter distance

between subject and detector. A slow-speed film:screen

system or a digital system with high spatial resolution will

provide better detail. Other factors that increase detail

include using a grid to reduce scatter radiation and avoiding

patient motion.

Question 22

detector

Answer 22

The part of an imaging system that captures the image. A detector may be film (conventional radiography) or a phosphor plate (digital radiography). X-rays that pass through the patient to the detector form the latent image.Other names: image detector, image receptor.

Question 23

development of x-ray film

Answer 23

Refers to the chemical process that converts activated silver halide crystals to metallic silver particles. Silver particles blacken the film to createthe final image. Development may be accomplished manually or using an automatic film processor.

Question 24

diaphysis

Answer 24

Between physes”; the middle portion or shaft of a long bone; the area between the metaphyses; a primary center of ossification of a long bone.

Question 25

DICOM (Digital Imaging and Communication in Medicine)

Answer 25

A specific file format (such as jpeg or tif) used to

store digital images and which contains information specific to the patient, type of digital equipment used, image transmission,and pixel data. DICOM files are safeguarded to prevent permanent altering of images and can only beviewed with a DICOM viewer.

Question 26

dirty lungs

Answer 26

Refers to an interstitial lung pattern; vascular and bronchial margins become partially obscured and appear hazy due to increased interstitial opacity.

Question 27

dural ossification

Answer 27

A degenerative condition of unknown clinical significance in the dog, characterized by osseous metaplasia of the dura mater.

Question 28

dysplasia

Answer 28

Refers to the abnormal development or growth of a structure (e.g., hip dysplasia, elbow dysplasia).

Question 29

dystrophic mineralization

Answer 29

The abnormal, localized precipitation of inorganic material in damaged, degenerating, or dead tissue.