General Q11-20

Question 1

Describe what should be included on the radiographic report:

Answer 1

Sufficiently detailed
Focus on the most important findings, but also list other abnormalities
Normal structures should be mentioned to confirm evaluation
Use anatomical and radiographical terminology
Mention views according to primary beam

Question 2

How is the structure of a radiographic report:

Answer 2

1. Name, age, gender, species, breed and owners name
2. Date
3. Which radiographs were evaluated and limitations if any
4. Description of x-ray image including shadows, anatomy, pathology and diagnosis
5. Interpretation, reading and diagnosis including correlation between clinical findings
6. Recommendations if any
7. Location of the clinic and name of the doctor

Question 3

What is the difference between native and contrast studies?

Answer 3

Native:
* plain radiograph, without any contrast medium
* limited because many organs and structures have similar tissue opacity

Contrast:
* uses non-toxic, non-irritant dye to make an organ stand out
* defined images, either by: selectively absorb more x-ray photons (white) or transmit more x.ray photons (black)
* should persist in the body for sufficient amount of time and be eliminated by body

Question 4

What types of contrast agents do we use?

Answer 4

1) Negative contrast media
* Gas - low density and appear radiolucent
- define locations of viscous
- room air, CO2, NO2

2) Positive contrast media
* high atomic number - radiopaque
* Barium: GIT studies
* Iodine: urinary tract, cardiovascular/portal system, joints, peripheral sinuses, fistulae, myelography, lymph
- water soluble
- ionic form: hyperosmolar
- non-ionic form: low osmolarity and no charge, myelography

3) Double contrast
* both negative and positive
* visualization of mucous - filling defects, calculi or wall thickening
* bladder

Question 5

How do we applicate contrast media?

Answer 5

Oral - GIT perforation, leakage, obstruction
Intravenous - blood vessels, urinary system
Viscera
Cavities
Joints
Peripheral lymph system
Myelography - into subarachnoid space at the cisternal or lumbar puncture site (L5-L6)

Question 6

Describe contrast study of esophagus:

Answer 6

Indications: foreign body, regurgitation, dysphagia, vomiting of undigested food.
* Native picture first
* Thick barium paste
* Laterolateral view
* Dilated esophagus: 20-30 ml 100% Ba suspension in food
* Blockages: common places are at thoracic inlet, over heart, at diaphragm
* Penetration - Barium should NOT be administered

Question 7

Describe contrast study of the stomach and small intestine:

Answer 7

To assess location of stomach in relation to liver and diaphragm, presence of dilation, displacement, masses or swellings.
* Withheld food for 24 hours
* Native radiograph
* 20-100 ml 100% BaSO4 sol.
* Take radiograph directly after and every 5 to 10 minutes
* 4 views: LL x2, VD and DV
* Gastric emptying < 15 min, might be 30-45 min (nervous animal)
* Abnormal emptying > 45 min, should reach large intestine within 4 hours

Question 8

Describe contrast study of the large intestine:

Answer 8

Indications: tenesmus, melena or chronic diarrhoea.
* Enema before contrast
* Diluted BaSO4 (10 ml/kg) by enema pump or catheter into terminal rectum
* LL and VD positions
* Normal mucosa is flat and smooth in dog and cat
* Mucosal irregularities, luminal narrowing, displacement by mass/lesions

Question 9

Describe the procedure of contrast study of abd soft tissues:

Why, dose and how

Answer 9

Visualize and differentiate abdominal soft tissues
Dose: 12 ml/kg bw orally of BaSO4 or non-ionic aqueous iodine (iodine better for GIT perforation).
Procedure:
1. Native radiograph
2. Administer contrast medium
3. 0 min - esophagus
4. 30 min - stomach
5. 60 min - stomach and small intestine
6. 120 - small intestine, large intestine
7. 4-6 hours - colon

Question 10

Describe contrast study of the kidneys and ureter:

Evaluation of what, position, methods

Answer 10

I.V. iodine (intravenous or excretory urography).
Evaluation of renal size, shape and location, structure, size and position of ureters.
* LL and VD
* 24 hours fasting and cleansing enema
2 techniques:
1. Low volume drip technique:
- 600-800 ml/kg iodine I.V
- pictures taken at 1, 5, 10, 15 and 20 min.
2. High volume drip technique:
- diluted - 1200 mg/kg
- infused over 10-15 min through IV catheter
- images taken 5, 10 and 15 min
- investigation of ureteric conditions (ectopic ureter)

Question 11

Describe contrast study of bladder:

Indications, position, method and evaluation

Answer 11

Indications: hematuria, dysuria, urinary retention, urinary incontinence.
* LL and VD
Methods:
* Bladder is cathetirized and drained first
1. Pneumocystography (negative) - bladder is filled with air
2. Positive contrast cystography - diluted iodine (bladder mucosa)
3. Double contrast cystography: 5-15 ml is injected into bladder, then filled with air.
4. Intravenous cystography - when catheterization is not possible (same as low volume drip technique)

Evaluation: Identification, localisation and integrity of bladder. Presence of stones, crystals, tumours, or leakage.

Question 12

Describe contrast study of urethra:

Indications and method

Answer 12

Indications: persistent hernia, dysuria, urinary incontinence, UT obstruction, evaluation of prostatic disease, lesions of os penis, urethratis or urethral neoplasia.

Method:
Male dogs - catheter up in penis, 5-10 ml contrast media.
VD view - to detect compressions or displacement of intra-pelvis urethra and prostatic lesions.

Question 13

What are the principles of radiographic evaluation (3)?

Answer 13

Pre-assessment
Basic interpretation
The radiographic interpretation

Question 14

What is included in pre-assessment?

Answer 14

Pictures in correct direction
- LL: head to the left
- VD or DV: head to the top, animals right side to the left
Check that correct markers are used (L/R)
Check that the entire area is included
Check that quality of image is sufficient
Check that patients name and date are correct

Question 15

What is included in the basic interpretation?

Phases

Answer 15

1. Recognition phase
   - systematic search start in the middle of picture, where the primary beam was located (area of interest)
2. Descriptive phase
   - identify and describe all changes/abnormalities
   - classify abnormalities:
   Size, shape, structure, surface, position, contours, number, opacity
3. Interpretive phase
   - possible differential diagnosis (signalment, history and clinical findings)

Question 16

What is included in the radiographic interpretation?

Answer 16

2 versions:

Direct browsing structures:
- ignore clear lesions first, look at the whole picture, collect all individual symptoms

Hypothesis-based search:
- use hypothesis to investigate a specific area
- use possible associations between the abnormalities discovered
- check the whole image

Question 17

What is ultrasound?

Answer 17

Imaging of soft tissue with use of high-frequency sound waves. Various body tissues conduct sound differently, some absorb while others reflect. Density = speed at which echoes return.

Question 18

Explain the physical nature of ultrasound formation:

Answer 18

1. Ultrasound is created by electrical stimulation of piezoelectric crystals.
   - crystals located inside transducer
   - crystals deform and start to vibrate, produce sound waves that goes through tissues
   - when sound beam encounter different tissues, a portion bounce back to the transducer (reciever)
   - crystals generate electrical impulses from the recieving echoes, proportional in strength to the returning echoes
   Low frequency –> deeper but lower quality
   High frequency –> not as deep, higher quality
2. Measurement of distance:
   Time between emission and return of echo
   Machine calculates time and show a scale

Question 19

Describe the colours in ultrasound:

Answer 19

Fluid = black
Tissue = grey
Bone = white

Question 20

Describe patient preparation in ultrasonography:

Answer 20

Good contact between probe and skin.
1) Shave area
2) Moist skin for better contact: alcohol on skin and gel on skin and probe (decrease impedance)
3) Proper positioning of the animal
4) Angle of transducer must be 90* perpendicular to tissue examined

Question 21

Appoint different modes of ultrasound:

Answer 21

A-mode (amplitude) - echoes displayed as voltage sounds
B-mode (brightness) - differentiate in brightness according to strength of returning echo
M-mode (motion) - returning B-mode echoes are plotted against time to form a tracing (cardiac evaluation)
Doppler - blood flow and vessel velocity (sound changes as it approaches and moves away), can show different colours depending on direction (red - towards, blue - away, green/yellow - turbulent)

Question 22

Appoint causes of artefacts in ultrasonography:

Answer 22

Acoustic enhancement
Acoustic shadow
Reverbation artefact
Pseudosediment
Refraction
Mirror-image artefacts
Edge-shadowing artefacts

Question 23

Explain artefact - acoustic enhancement:

Answer 23

Increased echoes deep to structures that transmit sound extremely well.
- fluid filled structures such as the urinary bladder and gall-bladder
- fluid attenuates sound less than surrounding tissue
- causes deeper tissues to be brighter
- increased echogenicity (hyperechogenic) posterior to cystic area

Question 24

Explain artefact - acoustic shadow:

Answer 24

Shadow under structures that absorb or reflect ultrasonic waves.
Solid structures, like bones or stones (anechoic/black shadow).
Pathological acoustic shadow - renal, cystic or cholecystic calculi.

Question 25

Explain reverbation artefact:

Answer 25

Ultrasound beam encounters two strong parallel reflectors. It reflects back and forth, and transducer interpret the sound waves returning from the reverbation as deeper structures.

Question 26

Explain pseudosediment artefact:

Answer 26

Periphery of bladder is imaged. Part of thickness of the primary sound beam strikes the bladder wall while the other part strikes anechoic urine - computer averages these two parts out to create the pseudosediment artefact.
* surface is curved, real sediment is flat
- use different angle to eliminate

Question 27

Describe refraction artefact:

Answer 27

Incorrect location of organs and measurement errors.
Transmitted ultrasound pulse does not hit the target in a perpendicular angle.
Different speed between two tissues can cause refraction to occur –> incorrect location of organs, usually to the side of the actual location, and measurement errors.
- solve by moving the transducer

Question 28

Describe mirror- image artefacts:

Answer 28

Duplication of a normal structure on the opposite site of the strong reflector surface.
* Often when liver is pictured with diaphragm/lung interface acting as a highly reflective surface

Question 29

Describe edge-shadowing artefacts in ultrasonography:

Answer 29

When sound waves are bent as they encounter a curved surface tangentially.

Question 30

What components is the ultrasound machine consisting of?

Answer 30

Transducer probe - sends and recieves sound waves
Central processing unit - does all calculations
Transducer pulse controls - changes amplitude, frequency and duration of pulses emitted
Display - image from US data processed by CPU
Keyboard/cursor - inputs data and takes measurements from the display
Disk storage device - stores images
Printer

Question 31

What types of probes do we know?

Answer 31

Linear array: rectangular image. Surface organs, musculoskeletal system, thyroid gland, mammary gland, vessels.
- vector or sector - cardiology, transcranial, invasive
- convex or curved array - abdominal exams, obstetrics, gynecology, urology
- microconvex - cardiology, abdominal organs

Transabdominal: obstetrics, gynecology, invasive treatment
Transrectal: urology, invasive treatment
- Transesophageal: cardiology, surgery
- Transvaginal: obstetrics, gynecology, urology, invasive treatment

Question 32

Acoustic window:

Answer 32

Area of defined pathway of US beam between transducer and acoustic reflector. Refers to optimal placing of transducers so that area of interest is clearly imaged.

Question 33

Acoustic impedance:

Answer 33

Resistance of tissues to ultrasonic irradiation and their ability to reflect sound waves back to the probe (absorption is the opposite).

Question 34

Acoustic amplification:

Answer 34

Correlates to the brightness of the produced image. Higher amplification = brighter image.

Question 35

Focusing:

Answer 35

Angle of the probe at which the desired structure is best viewed.

Question 36

What is gain?

Answer 36

Gain affects the amplification of the returning echoes within the reciever. Increasing or decreasing gain = increased or decreased brightness.

Question 37

What is zoom?

Answer 37

Setting on US machine that allows you to look closer at a structure.

Question 38

What is freeze?

Answer 38

Freezing the image on the US screen and taking a picture.