radiology 1-3 (diagnostic quality, roentgen signs, reports) Flashcards
(24 cards)
what is the minimum number of orthogonal views that should be taken?
a minimum of 2 at 90 degree differences
- for thorax three (L and R lateral, a DV or VD)
- abdomen ideally three (L and R lateral, VD)
is this radiograph over or under exposed?
over exposed - toast analogy (too light = under, too dark = over)
why is this radiograph so “grainy”?
a. underexposed
b. overexposed
c. patient has decreased bone density
a. underexposed - the digital plate has not received enough data points to make a clear image (exposure factors were insufficient)
what’s wrong with the positioning of this radiograph?
the dog is rotated - the sternum is lateral to the vertebrae, they should be in line
Roentgen signs (also called radiographic signs) are used to describe abnormalities in a radiograph. they consist of
- Location
- Number
- Shape
- Opacity
- Margins
- Size
location - use directional terminology (such as cranial, medial), usually in combination with nearby anatomical structures or regional terms (e.g. thorax, antebrachium, caudal abdomen, proximal metaphysis).
How would you describe the location of the white X on this left lateral thoracic radiograph of a normal dog?
caudodorsal thoracic region
Describe the location of the X in the radiographic images of a normal cat’s thorax
cranioventral thorax (in the mediastinum - can see it’s on the midline)
Why is it often harder to make out where the right kidney is?
because it’s more cranial and makes contact with the liver, which makes it hard to distinguish (both soft tissue opacity)
This is a pregnant bitch. How many puppies are there?
one - giga puppy
what are the five opacities?
- air
- fat
- soft tissue
- bone/mineral
- metal
Using the Roentgen signs we’ve discussed so far to describe the abnormal findings i.e. location, number, shape, opacity )
Location: urinary bladder i.e. midline within the caudoventral abdomen
Number: multiple (at least five)
Shape: triangular to round
Opacity: mineral
“the urinary bladder contains multiple triangular to round mineral opacities”.
The term “margins” refers to the edges of structures.
Margins may be well-defined or poorly-defined.
Margins may also be described as smooth, rough, undulating, or corrugated
how would you describe the margins on the mineral opacities in the bladder?
smooth, well defined margins
intestinal margins - are they well or poorly defined?
well defined
intestinal margins - are they well or poorly defined?
poorly defined - difficult to see
*patient has a condition called “carcinomatosis” in which the peritoneal surfaces (i.e. serosal margins) are covered with huge numbers of tiny metastatic nodules. The nodules are too small and too numerous to see individually but, together, they cause border effacement of the intestinal margins.
To complete the description, we have to give an idea of size. To do this we need to consider:
- Actual size vs magnification
- Normal variations in organ size (eg stomach empty vs after a meal)
- Size compared to another structure.
- Effect of organ size on adjacent organs: displacement
what’s the problem with these femurs?
magnification - should especially be kept in mind when assessing limbs. - The further the limbs are away from the plate the larger they will appear on radiograph.
- If the limbs are not parallel to the plate, we can get unequal magnification of parts of the limb and subsequent misrepresentation of the actual shape.
The further the object is away from the plate the….
a. larger they will appear on radiograph
b. smaller they will appear on the radiograph
a. larger they will appear on radiograph - magnification
*use calibrator for orthopaedic surgeries etc
which is most radiolucent?
air, fat, soft tissue, bone/mineral, metal
air - most radiolucent (“blackest”)
which is most radiopaque?
air, fat, soft tissue, bone/mineral, metal
metal - most radiopaque (“whitest”)
which opacity is fluid?
a. air
b. fat
c. soft tissue
d. bone
c. soft tissue - this makes it hard to distinguish on a radiograph
what do you need to include in a 3rd year report?
list the roentgen signs in the order they should be used (makes report writing easier)
location, number, shape, opacity, margins, size
Which description below best describes the radiographic finding outlined in red?
A: Within the small intestine there is a single area of mottled gas and soft tissue opacity.
B: Within the small intestine there is one rectangular region of mixed opacity with well defined margins, approximately 4.5x 3cm.
C. A corn cob is stuck in the intestine.
B: Within the small intestine there is one rectangular region of mixed opacity with well defined margins, approximately 4.5x 3cm.
*other two descriptions do not include all the roetgen signs
Use roentgen signs to write a radiographic description about what is within the yellow circle.
Use roentgen signs to write a radiographic description about what is within the yellow circle.
