STEEPLECHASE ULTRASONOGRAPHY Flashcards
1
Q
Frequency
A
No. diff sound waves that pass through point at any given time
2
Q
High freq
A
- Good axial resolution
- More rapid beam attenuation - lose energy from beam quicker
- Poor penetration
- Cardiac scanning- better resolution, low penetration
3
Q
Low freq
A
- Poor axial resolution
- Less rapid beam attenuation
- Better penetration
- E.g. Large dog w/ deep abdo
4
Q
Depth
A
Should be set so image takes up 2/3 of screen - centimetre markers
5
Q
Gain
A
- Overall brightness of image
- Further from the probe, more gain required to achieve same level of brightness
- Time gain compensation (TGC) - controls brightness at diff levels through tissue
6
Q
Focus/focal zone
A
- Improves lateral resolution - targets perpendicular to beam distinguished from each other
7
Q
Echogenicity
A
- Due to beam attenuation - reflects normal tissue back to transducer, fluid e.g. cysts = attenuation
- Normal organs + tissues displayed as shades of grey
8
Q
Isoechoic
A
Structures same shade of grey
9
Q
Hypoechoic
A
Darker shade of grey
10
Q
Hyperechoic
A
Lighter shade of grey
11
Q
Anechoic
A
- Black structure
- E.g. Fluid, cyst
12
Q
Describing US image
A
- L - location - normal/displaced?
- E - echotexture - anechoic, hypoechoic, isoechoic, hyperchoic; homo/heterogeneous
- M - measurement/size
- O - outline/margin - disruption/capsule of organ - smooth, well-defined?
- N - No. organs correct, lesions etc
- S - shape/size - reference to another organ
13
Q
Artefacts
A
- Reverberation - gas/parallel reflective surfaces -> hyperechoic parallel bright lines e.g. in lungs
- Mirror image - highly reflective curved surfaces e.g. diaphragm
- Acoustic enhancement - US beam not attenuated by fluid + passes straight through -> bright acoustic area distal to fluid filled structure e.g. bladder/gall bladder
- Acoustic shadowing - highly attenuating structure e.g. calculi/bone/gas (get comet tail) - all waves reflected -> hypoechoic shadow below structure
- Edge shadowing - beam changes direction at fluid/tissue interface -> hypoechoic streaks from curved structure edge
- Poor probe contact - insufficient clipping/not enough gel -> air trapping
- Slice thickness - pseudo-sludge e.g. bladder/gallbladder, part of beam is wider than cystic (circular structure), mimics tissue interface within fluid-filled structure
14
Q
A
Distal acoustic enhancement
15
Q
A
16
Q
A
- Spleen heterogenous compared to liver; liver more homogenous, only in comparison!
- If spleen itself was heterogenous, tumour within spleen, more epitexture
17
Q
A
Heterogenous - haemangiosarcoma/lymphoma, tumour
18
Q
A
19
Q
A
20
Q
A
Acoustic enhancement
21
Q
A
22
Q
A
23
Q
A
24
Q
Indications - POCUS SCAN (point of care US) - emergency (abdo)
A
- Identify and sample free fluid
- Identify free gas
- Evaluation the intestines for obstruction
- Evaluate pancreas region for signs of inflammation
- Evaluation the biliary tract for signs of obstruction or perforation
- Evaluation of the urinary tract for obstruction or rupture
25
Q
Indications - elective (abdo)
A
- Medical + Sx work-up
- Staging of neoplasia
- Abdo organ/mass sampling
- Intra-abdo biopsy
- System specific investigation e.g. pyo, PD, ascites
26
Q
Equipment + patient prep
A
- Microconvex transducer
- 5 - 8 MHz
- Withhold food for 12 hours
- Appropriate environment - quiet, low lighting, animal comfortable
- Abdominal hair clipping - from xiphoid to pubis
- Dorsal or lateral recumbency - don’t place unstable in dorsal
- Assistants for restraint
27
Q
Approaching US exam checklist
A
- 1). Number – correct number organs / single or multiple abnormalities
- 2). Location – does an abnormality displace an organ
- 3). Function – is the heart beating/the GI tract peristalsis etc.
- 4). Size – can you compare to breed ‘normal’
- 5). Echogenicity – focal or diffuse changes
- 6). Architecture – disruptions often marked in chronic disease
- 7). Shape – very subjective, although can be affected by masses
- 8). Margins – normally smooth and well defined
28
Q
POCUS abdo protocol
A
- Logical approach
- Each organ evaluated in all planes + fanning probe
- Identify abnormalities
- R lateral = xiphoid process -> liver -> stomach -> spleen -> L kidney -> SI -> colon -> urinary bladder -> +/- prostate
29
Q
POCUS - AFAST - sites
A
- DH = diaphragmatic-heptic view
- CC = cystocolic view
- SR = splenorenal view
- HR = hepatorenal view
- Each site in two planes at 90 degrees
- Give abdo fluid score - 0 - 4 for no. fluid +ive areas, inc score w/ ongoing fluid accum, dec score = resorption of fluid
30
Q
DH - Diaphragmatic hepatic view
A
- Diaphragm
- Fluid
- Cranial
31
Q
CC - cystocolic view
A
- Back of abdo (caudal)
- Bladder
- Colon
32
Q
SR - splenorenal view
A
- Spleen
- Kidney
- LHS
33
Q
HR - hepatorenal view
A
- Liver
- Bladder
- RHS
34
Q
Liver
A
- Pos - cranial abdo, begin scanning from xiphoid process of sternum
- Normal = medium echogenicity + homogenous, size difficult to determine
- Hepatic v enters via CVC ventrally
- Portal vein - bright white walls due to fibrous content
35
Q
Gall bladder
A
- Pear shape/bi-lobed in cats
- Thin walls -> echogenic line
- Bilary tree not normally seen (if dilated = too many ‘tubes’)
36
Q
A
- Liver neoplasia
- Focal lesions likely metastasis
37
Q
A
- Liver neoplasia
- Hypoechoic areas of cavitation
38
Q
A
- Steroid-induced hepatopathy
- Hyperechoic w/ rounded border
39
Q
A
- Normal gall bladder
- Pseudo sludge + acoustic enhancement
40
Q
A
Gall bladder - sediment
41
Q
A
Gall bladder - mucocele
42
Q
Spleen
A
- Pos - left body wall
- Normal - fine granular texture, hyperechoic to liver, more echogenoic than renal cortex, variable in size
43
Q
A
Spleen
44
Q
A
Splenic neoplasia
45
Q
GIT
A
- 5 layers - ideally 7.5 MHx to visualise all layers
- Serosa = hyperechoic
- Muscularis = hypoechoic
- Submucosa = hyperechoic
- Mucosa = thick hypoechoic
- Lumen interface = hyperechoic
46
Q
GIT - thickness of wall layers
A
47
Q
Stomach
A
- Caudal to liver, rugal folds (spoke wheel)
- Measure wall thickness between rugal folds
- Areas often obscured by gas/ingesta
48
Q
Stomach - abnormalities
A
- Pos
- Size
- Mural lesions - gastric ulcerations, FB
49
Q
A
Gastric ulceration
50
Q
Small intestine
A
- Duodenum - straight course curving to join pylorus
- Ileum - more prominent submucosal layer/ileocolic junction in fixed pos right mid abdo
- Large intestine - thin wall, assessment difficult due to shadowing from faeces
51
Q
A
- Intussusception of SI w/ characteristic multi-layer appearance
- > 5 layers
- Young puppies - high worm burden
- Neoplasia
52
Q
A
- SI - inflam bowel disease
- Mucosa increased echogenicity
- Focal hyperechoic speckles
53
Q
A
- Circumferential wall thickening + loss wall layering
- Suggestive of neoplasia (callipers indicate wall thickness)
54
Q
Pancreas
A
- Pancreatitis = hyperechoic mesenteric fat, localised free fluid, may appear enlarged, hypoechoic + heterogenous; cannot be distinguished from neoplasia by US, + Dx tests
- If cannot find on US = normal
- Similar echogenicity to mesenteric fat, fan slowly to identify
- Easier to see on LHS - due to spleen
55
Q
A
Body of pancreas (BP) caudal to pylorus of stomach (S), with portal vein (PV)
56
Q
A
- Land markers for R limb pancreas
- Duodenum (top)
- Caudate lobe liver (bottom left)
- Right kidney (bottom right)
57
Q
A
Landmarks for L limb of pancreas
- Spleen (Sp)
- Stomach (St)
- Colon (C)
- Splenic vein (SV)
58
Q
Kidneys
A
- Pos - right more difficult to image as more cranial and dorsal
Normal Anatomy - Capsule – thin hyperechoic line
- Cortex – medium echogenicity (glomeruli and vasculature)
- Medulla – hypoechoic triangular sections caused by intralobar vessels
- Renal Sinus – hyperechoic (fat)
- Ureter – anechoic but not seen unless dilated
59
Q
Kidneys size
A
60
Q
A
- Ethylene glycol toxicosis
- Hyperechoic cortex and medullary rim sign. (arrow)
61
Q
A
- Renal tumour - heterogenous mass at caudal pole
62
Q
A
- Hydronephrosis - dilated renal pelvis, lost differentiation
- DDx = obstructed kidney -> ureteric stone, > 7 mm + presenting CS
63
Q
A
- Renal cysts - hypoechoic smooth, round structures disrupting normal architecture
64
Q
Left adrenal gland
A
- Between kidney + aorta, cranial to L renal a.
- Bean/peanut shape
- Hypoechoic
65
Q
Right adrenal gland
A
- Medial to R kidney
- Superimposed over CVC
- Bent arrow shape
- Hypoechoic
66
Q
A
Normal feline left adrenal gland, smaller + more oval-shaped
67
Q
Adrenal glands - abnormalities
A
- 7 - 8 mm max in dog
- 4 mm max in cat
- Mineralisation of tumours in dogs = suspicious of carcinoma
- Pituitary dependent HAC - both moderately enlarged + hypoechoic
68
Q
A
Adrenal gland hyperplasia - patients undergoing trilostane therapy (Cushing’s)
69
Q
A
- Neoplasia of the Right adrenal gland
- Sagittal plane image shows a hypoechoic mass in the region of the right adrenal gland (red arrow)
- Invasion of the adjacent caudal vena cava (blue arrow) and interruption to the blood flow within the vena cava can be seen (red asterisk) by the lack of coloured pixels within the colour doppler sample gate (yellow box)
70
Q
Urinary bladder
A
- Bladder wall = 1.5 - 2.5 mm (dog) / 1.3 - 1.7 mm (cat)
- Wall will appear thicker if bladder empty
- Contents should be anechoic
- Echogenic material seen in suspension (cellular debris/sediment/crystals)
71
Q
Urinary bladder artefacts
A
- Slice thickness – pseudo sludge (will not move with gravity)
- Acoustic enhancement
- Acoustic Shadow ( if urinary calculi)
72
Q
A
Bladder calculi - distal acoustic shadowing
73
Q
A
Chronic cystitis - thickening of bladder wall
74
Q
A
Bladder neoplasia - echogenic mass w/o distal acoustic shadowing
75
Q
Prostate
A
- Pos - caudal to bladder + ventral to descending colon
- Normal = thin capsule, bilobed + symmetrical either side of urethra, will appear more hypoechoic in castrated animals
76
Q
A
Prostatitis w/ abscess - hypoechoic nodule within parenchyma
77
Q
A
Benign prostatic (generalised) enlargement - hyperechoic + smooth appearance - most common
78
Q
A
Prostatic adenocarcinoma - irregular margin + heterogenous echotexture
79
Q
A
- Leydig cell tumour
- A - longitudinal
- B - transverse
- Circumscribed hypoechoic mass w/ two anaechoic regions
80
Q
A
Uterus - pregnancy, conceptuses present from 30 d
81
Q
A
Uterus - pyometra
