# Normal Cardiac Imaging

version from 2017-10-12 15:18

Main difference between lateral views?
More sternal contact on RLR
Is VD or DV preferred for cardiac imaging?DV
What can you see in a VD view?2 crura separate to tendinous portion of the diaphragm
Elongated cardiac silhuoette
Apex shifted more to midline
What’s the difference here?
Left = expiration. Right = inspiration
Cardiac silhouette in deep-chested breeds (Doberman etc)?Tall & upright
Cardiac silhouette in barrel-chested breeds (Bassett etc)?Globular shape
What are the arrows pointing to?
(hint: Bassetts, Dachshunds)
Normal costochondral indentations
Size of cardiac silhouette in dog (Lateral): ___x ICS2.5 – 3.5x IC rib spaces
Size of cardiac silhouette in dog (Lateral): ___ the height of the thoracic cavity<2/3
In shallow-chested dogs, how is the measurement of the height of the cardiac silohuette different?May occupy more on the lateral, but be normal on the DV
Size of cardiac silhouette in dog (Lateral): Vertebral heart score =___9.7 (+/- 0.5 vertebral bodies) average (marked breed variations now reported)
Vertebral heart score for normal adult cats =7.5 (+/- 0.3)
Size of cardiac silhouette in dog (DV): ___ the width of the thoracic cavity<2/3 at its widest point
Something to keep in mind when measuring the cardiac silohuette on DV?Measurement varies depending on degree of inspiration
How do you calculate the vertebral heart score?Measure height of cardiac silhuoette from apex to base, then line it up with the cranial aspect of T4 and note the vertebral length. Then measure the maximal width of the heart (right angle to first measurement), line it up with T4 again. Add the 2 T4 measurements together
Size of cardiac silhouette in cat (Lateral): ___x ICS2 – 2.5 IC rib spaces craniocaudally
Size of cardiac silhouette in cat (Lateral): ___ the height of the thoracic cavity2/3 (same as dog)
Size of cardiac silhouette in cat (Lateral): ___ the width of the thoracic cavity2/3 (same as dog)
Size of cardiac silhouette in cat (DV): ___ the width of the thoracic cavity<2/3 at its widest point (same as dog)
How does the cardiac silhuoette lie in the cat?Lemon-shaped, 45* angle to the sternum
Special radiographic finding in older cat’s cardiac silohuette?Prominent aortic arch: “knuckle” protrusion in left cranial mediastinum
(angle of heart to sternum also becomes more oblique with age)
What is the ‘thymic sail?’An oblique soft tissue opacity seen in VD or DV views, due to the presence of the thymus in the ventral part of the cranial mediastinum
What are the arrows pointing out?
Fat in the pericardial sac! (gray halo)
Clock face analogy (DV): 11-1Aorta
Clock face analogy (DV): 1-2Pulmonary artery
Clock face analogy (DV): 2-3Left auricle
Clock face analogy (DV): 3-5Left ventricle
Clock face analogy (DV): 5-9Right ventricle
Clock face analogy (DV): 9-11Right atrium
Clock face analogy (DV): where is the left atrium?Superimposed over center of heart caudal to tracheal bifurcation. CAN’t SEE IN NORMAL ANIMAL!
Clock face analogy (Lateral): 12-3Left atrium
Clock face analogy (Lateral): 3-5Left ventricle
Clock face analogy (Lateral): 5-8Right ventricle
Clock face analogy (Lateral): 8-10Right atrium
Clock face analogy (Lateral): 10-12Great vessels (Ao + PA)
Shadow lost under mediastinal structures, so only see in abnormal cases!
This selective right-heart angiogram is basically telling us…
RA & RV are predominant cranial structures (catheter in jugular --> CVC --> right ventricle)
This image proves that...
Left side of heart is more caudal
What do we assess on radiographs of the heart?Size & shape of silhouette & cardiact chambers
Size of blood vessels in the lung fields

## Ultrasound

Ultrasound exam =Echocardiography
Higher frequencies (7.5-15MHz) travel ___ distances into tissueShort
2.5MHz transducer: travel how far? Image quality?24cm but relatively poor image quality (horses)
7.5MHz transducer: travel how far? image quality?5-8cm, excellent resolution (small patients)
Important thing to remember about the acoustic window?Needs to be where heart is in contact with ribs (air doesn’t transmit sound!)
Where is the left lateral thoracic window?Cardiac notch (= where heart is in contact with ribs & intercostal spaces)
Where is the right lateral thoracic window?
(Bigger on right side)
How do we scan to get a good acoustic window?From underneath to compress the lung & expand acoustic window
In the long-axis 4 chamber view, the ___ are displayed to the right and the ___ on the leftAtRia on the Right, ventricLes on the Left
In what view can we see the aortic outflow? How do we get it?Right sided parasternal. Rotate the transducer 5* from the long-axis 4 chamber view
Besides the aortic outflow, what else can we see with right parasternal?2 of the 3 cusps of aortic valve
What view?
Right sided parasternal location (long axis view of aortic outflow tract)
How should you move the transducer? (in general)Don’t move it- just tilt! Don’t want to lose acoustic window
What’s goin on in this pic?
Can take different slices depending on what structures you want to see
PM stands for? (this is R side parasternal transverse short axis LV plane B)
Papillary muscles (1 on each side, anterior & posterior, indenting into lumen. VS = interventricular septum)
Should be symmetrical!
AMV = ? PMV? (this is short axis MV plane D)
Anterior & posterior mitral valve leaflet
Which view is this? What are NC, RC, LC?
Transverse, short axis, aortic valve level Plane E (can see all 3 leaflets!)
NC = non-coronary cusp of aortic valve
RC = Right coronary cusp of AV
LC = Left coronary cusp of AV
Special thing you can see on aortic valve level Plane E?All 3 cusps of aortic valve!
Where is the transducer with Apical view?Apex closest to transducer
What can you see with 4-chamber apical view?Inflow view (all 4 chambers)
What can you see with 5-chamber apical view?LV outflow view (all 4 chambers + Aorta) (also see 3cusp & MV really well)
Which view is this?
Apical view of heart (4-chamber view)
How does M-mode work?With cursor, select area to get tracing (b/c when you freeze the US, image gets slightly blurred)
What is the M-mode echocardiogram (trace) showing you?Extent of contraction & relaxation suring systole & diastole
M-mode: what is the B measurement?Where interventricular septum (IVS) & posterior ventricular wall (PVW) are widest (biggest LV lumen)
M-mode: what is the E measurement?Where interventricular septum (IVS) & posterior ventricular wall (PVW) are narrowest (smallest LV lumen)
End Point Septal Separation (EPSS) =Distance from tip of septal leaflet of MV to the septum (using either long or short axis)
EPSS in dogs should be<7mm
What are the arrows pointing to? s & d mean what?
Short arrows = EPSS measurement location
s = systolic phase of MV. d = diastolic
Fractional shortening is used for what?Assess contractility of LV
(Diastolic-systolic / Diastolic / 100)
What should you know about the normal values for M-mode echocardiographic measurements?Each species & breed has different normals. Look it up!
Duplex mode does what?Capable of displaying 2D & M-mode moving/updating at the same time
Some machines can update both at same time, others can only display movement in 1 while other is paused
Doppler effect:Frequency of sound changes with velocity of flow (Ambulance coming towards you has different pitches as it comes closer/goes away)
Doppler mode can determine what?Flow direction
Flow velocity
Uniformity of flow
Color flow doppler used for what?Screen large sections of the heart chambers & vessels
Color flow doppler: color codeingRed = towards transducer
Blue = away from transducer
Bright colors like yellows, greens = turbulence
(remember BART. also, RED & BLUE DON’T MEAN ARTERIAL & VENOUS!!)
What’s going on in this CFD? (this is rt side parasternal long axis 4-chambered view)
Bright colors regurgitating through MV into LA due to turbulence caused by MV insufficiency. (LA is enlarged too)
The really small blue-green jet in this CFD means?
Regurgitation (tricuspid)
Normal directional flow = red color going through tricuspid
Why are there bright colors through the aortic outflow tract?
Turbulence caused by narrowing of outflow (thickened IVS, LV lumen reduced)
(Cat with severe cardiomyopathy)
Pulsed wave doppler: does what?Way of accurately measureing blood velocity as it goes through valve
How does pulsed wave doppler work?Specific sample gate is placed along line of interest over heart or vessel, precise velocity of blood measured, pressures within vessels calculated from these measurements
Pulsed wave doppler: important to remember about the cursor?MUST BE PARALLEL WITH BLOOD FLOW
Pulsed wave doppler wave measurements?Time measured on horizontal axis
Speed of flow measured on vertical axis
Pulsed wave doppler waves should look?Flow is below baseline, has clear inner envelope indicating blood cells are moving at a similar velocity
(arrow = aortic outflow)
Pulsed wave doppler: flow is below the baseline in this image (cross-section view, level of pulmonary valve) because? (what’s the arrow?)
Atrial to ventricular flow is away from the transducer
Arrow = sample gate location distal to the PV (where velocity of blood in pulmonary artery being measured)
Pulsed wave doppler: flow is above the baseline in this image (apical view MV) because? (top & bottom arrows are?)
Atrial to ventricular flow is towards the transducer
Top arrow = E point, bottom = A point
What is the E point?Shape of anterior MV on M-mode & Doppler: during early diastole there is rapid ventricular filling, anterior MV leaflet opens and approaches the IVS (=E point)
What is the A point?MV reopens after diastolic filling of LV, leaflet moves towards septum again. A point = after P wave on ECG & atrial contraction
(What is the C point?)(During systole the MV leaflets move into apposition)
EPSS is ___ related to the LV ejection fractionInversely
Continuous wave doppler: used when?ONLY when velocities are too high for precise measurements using PWD (usually require special didicated transducers)