Radiology quiz: dentals and hip dysplasia

generator on dental unit

1. size and efficiency

2. where mounted

3. settings

4. arm

5. outlet

1. smaller, more efficient

2. wall

3. preset (70 kVp, 6-8 mAs)

4. 180 degree swing

5. standard 110v

dental unit x-ray tubing

1. anode type

2. what focuses beam

3. tube position

1. small stationary

2. lead lined extension cones

3. 10 cm from patient

3 types of dental imaging

traditional film screen, direct digital, computerized

computerized radiology dental

1. receptors

2. plates

3. processing

4. cassette

1. variety of sizes, disposable

2. easily damaged

3. not as fast as dr

4. plastic cover that protects it and has phosphor plate and image receptor

incisors

used to grasping and cutting food, single rooted

canines

used for grasping and holding, single rooted

pre-molars

designed for cutting/shearing, single to three rooted

molars

flattened occlusal surfaces used for grinding, double to three rooted

lingual

toward the tongue

palatial

towards the palate

labial

surfaces of incisors that face the lip

buccal

lateral surfaces of all teeth except incisors

distal

direction towards the last tooth in each quadrant

mesial

direction towards the anterior or first tooth in each quadrant

anatomical system

uses numbers and letters in which letters designate tooth group and numbers indicate location of tooth group

modified triadan system

combo of three letters for each tooth, divides mouth into 4 quadrants with 1st letter representing quadrant and last 2 represent numbered tooth from midline

modified triadan system and quadrants

1=upper right

2=upper left

3=lower left

4=lower right

parallel technique

1. film placement

2. beam placement

3. intended for teeth

1. behind and parallel to tooth

2. perpendicular to film

3. distal to and including 307/407

bisecting angle technique

1. used for

2. formed by

1. all incisors, canines, maxillary, and mandibular pre-molars 1 and 2

2. intersection of film plane and long axis of tooth

parallel technique: plate/film sensor and long axis of tooth

parallel to each other

parallel angle technique: tube head/beam in regards to plate and tooth

perpendicular

in bisecting angle, tube head is perpendicular to what and not what

perpendicular to bisecting angle and not tooth or plate

simplified technique

1. relies on angle between

2. what angles used

1. position of tube head and sensor/plate

2. 45,70,90

simplified technique: mandibular premolars/molars

1. roots

2. exposed at what degree

3. plate/sensor

4. beam

1. parallel to visible crown

2. 90 to long axis of tooth

3. parallel to tooth

4. perpendicular to tooth

simplified technique: maxillary premolars/molars

1. roots

2. exposed at what degree

3. plate/sensor

4. beam

1. straight and parallel to visible crown

2. 45 degrees to sensor

3. flat across hard palate creating 90 degree angle but when bisected creates 45 degree angle

4. 45 degree angle to tooth

simplified technique: canines/incisors

1. roots

2. exposed at what degree

1. curve caudally at about 40 degree angle to palate/body of mandible

2. 70 degrees to sensor

technique errors with dental rads

elongation, foreshortening

elongation

1. results from

2. images appear

3. may miss

4. x-ray tube

1. central beam closer to right angle to long axis of tooth as opposed to bisecting angle

2. stretched with very long roots

3. portions of tooth

4. too vertical: flatten it out

foreshortening

1. results from

2. image appears

3. x-ray tube

1. center of bream being at a right angle to film and not aligned with bisecting angle

2. short and blunted with crown overlapping roots

3. too flat: make it more vertical

hip joint composed of

femoral head (smooth and rounded) and acetabulum (socket) which the femoral head should fit snuggle into

surfaces of joint covered with

articular cartilage

bone supports

bodies weight

cartilage allows

joint to move and separate bones glide over eachother

snug articulation between acetabulum along with supporting structures provide

stability

vd extended view

1. position

2. beam center

3. collimation

1. dorsal recumbency, hind legs extender and internally rotated

2. midline along caudal border of ischium

3. cranial border of wings of ilium and distal to patellas

vd frog leg

1. position

2. beam center

3. collimation

4. measure

1. dorsal recumbency with rear legs in natural flexed position

2. caudal border of pubis

3. cranial to wings of ilium, caudal to ischium, 1/3 of each femur laterally

4. thickest portion of pelvis

lateral pelvis

1. position

2. beam center

3. collimation

4. measure

1. lateral recumbency with affected leg down and positioned cranially

2. greater trochanter

3. cranial to wing of ilium, caudal ischium, 1/3 of each femur

4. greater trochanter

dysplasia

poorly formed

laxity

looseness

luxation

dislocation of a joint

subluxation

partial dislocation of a joint

arthritis and hip dysplasia

not every dog with arthritis has hip dysplasia but every dog with hip dysplasia will develop arthritis

hip dysplasia

developmental condition where the hips did not properly form (dysplasia) that results in increased movement and looseness (laxity) with potential for chronic instability and either full or partial dislocation of the joint over time (luxation/subluxation)

in severe cases, subluxation can progress to

degenerative joint disease or osteo-arthritis

how do dogs get hip dysplasia

inherited (polygenic: inherited by more than one gene or many genes)

environmental factors of hip dysplasia development

overweight, injury, overexertion at a young age

most common breeds with hip dysplasia

gsd, labs, goldens, rotties, all breeds can be affected

clinical signs of hip dysplasia

bunny hopping, stiffness, pain, lameness, abnormal gait (hip sway)

dysplastic hip anatomy

1. femoral head

2. acetabulum

1. doesn't fit snuggly into acetabulum, may appear flattened and loose

2. is not concave for proper fit of femoral head and poorly shaped

end result of hip dysplasia

shallow acetabulum and flattened femoral head leading to djd

ofa

1. must follow

2. film markers

3. age

4. categories

1. avma guidelines for positioning

2. permanently identified

3. 2 years old

4. 7 categories from excellent to severe

ofa positioning

1. position

2. rear limbs

3. knees

4. pelvis and hips

1. dorsal recumbency

2. extended and parallel to each other

3. internally rotated

4. symmetric

ofa film requirements

1. vd extended view: stifles

2. pelvis

3. patella

1. rotated inward

2. square: halves must be same size (look for symmetry in obturator foramen)

3. between condyles (parallel to each other)

penn hip based of method of

hip laxity

penn hip and distraction formula

used to assign numerical value that is correlated to probability of developing oa in future (<0.3 considered very low risk)

penn hip: how are dogs grouped

according to percentile ranking related to breed average: if > breed average, considered ok for breeding

3 views in penn hip study

distraction, compression, hip extended

hip extended view

same as ofa, primarily used to screen for presence of abnormalities such as djd: allows femoral head to be pushed into acetabulum

compression view

femurs positioned in neutral position with femoral heads pushed fully into socket: helps show true depth and fit of ball in socket

distraction view

similar to compression but specific positioning device used to create laterally directed force: shows actual degree of passive laxity present within joint

penn hip importance

1. must be

2. age

1. certified

2. 16 weeks