Module 4 : PLAX 2D Views and Measurements Flashcards
what view can every measurement be taken in
parasternal long axis
PLAX structures anterior to posterior
- pericardium
- +/- pericardial fluid
- RV anterior wall
- RV cavity
- interventricular septum
- AV
- right coronary cusp
- non coronary cusp
- aortic sinus
- LV cavity
- MV
- anterior mitral valve leaflet
- posterior mitral valve leaflet
- left atrium
- posterior LV wall (posterolateral wall)
- descending thoracic AO
1st protocol image
- PLAX extra depth
- depth set to 20-25 cm
- PURPOSE IS TO LOOK FOR PERICARDIAL OR PLEURAL EFFUSIONS
- Frame Rate not important in this image
2nd protocol image
- PLAX with normal depth
- ensure all structures are clearly seen
- LV/RV , endocardium, MV, AV, AO, sinus all clear
- don’t need all of apex
- try to make perpendicular
what to do before you measure
- ensure sector depth is no deeper than posterior wall of descending thoracic aorta
- sector width is narrow enough to produce 20 fps
- try to make LV walls perpendicular to beam
cine loop characteristics
- stores 1-5 beats
- use to show motion and blood flow
still image characteristics
- used for measurments
- used when do not need to show motion or blood flow
- used when a particular frame shows the structure better than wall motion
+ very small things
end diastole PLAX measurements
- end diastole is when ventricle is at its biggest and both valves are closed \+ IVS (interventricular septum) \+ LVIDd ( LV internal dimension) \+ LVPW (LV posterior lateral wall) \+ aortic sinus \+ ascending aorta \+ sometimes sinotubular junction DONE AT CHORDAE
end systole PLAX measurements
- end systole is when ventricle is smallest and both valves are closed
+ LVIDs
+ LA
mid systole PLAX measurements
- right when valves first open
+ LVOT diameter (left ventricular outflow tract)
how does being perpendicular to IVS improve accuracy of measurements
- it improves the axial resolution rather than lateral resolution so you can assess where the walls are more accurately
levels of the LV
- base
- mid
- apex
base level of LV
- from the mitral valve to the superior tip of the pap muscle
mid level of LV
- from the top to the bottom of the papillary muscle
apex level of LV
- inferior to the pap muscle
interventricular septum measurement
- measure perpendicular to the LV wall
- measure the IVS from the fine line where the IVS switches from RV to LV to the LV wall chamber
- IVS and posterior wall thickness should be roughly the same thickness
SIZE OF NORMAL IVS IN MEN
< 10mm
SIZE OF NORMAL IVS IN WOMEN
< 9mm
left ventricular internal diameter diastole (IVIDd) measurement
- also called LV minor axis
- from endocardium of the IVS to the endocardium of the LVPW
- measured in the basal segment only
SIZE OF NORMAL IVIDd MEN
< 59mm
SIZE OF NORMAL IVIDd WOMEN
< 53mm
LV posterior wall measurement
- also called INFEROLATERAL WALL
- measure from the anterior border oft eh LV chamber to the beginning of the right echoes of the pericardium
SIZE OF NORMAL LV POSTERIOR WALL MEN
< 10mm
SIZE OF NORMAL LV POSTERIOR WALL FEMALE
< 9mm
aortic measurements
- in normal routine only measure aortic sinus and ascending aorta
- only measure others if dilated
aortic sinus measurements
- leading to leading edge
- widest part of bulb
ascending aorta measurements
- about 2 cm distal to sinotubular junction (STJ) with leading to leading edge
SEVERE AORTIC SINUS OR ASCENDING AORTA DILATION
> /= 50mm
left ventricular outflow tract (LVOT)
- measured in mid systole or just after aortic valves open fully
- 5mm inferior to AV cusp insertion point on the LV side of the AV
- ANY ERRORS IN THIS MEASUREMENT WILL AMPLIFY ERRORS IN OTHER CALCULATIONS LIKE SV/CO/AVA
LVOT DIAMETER IN 80% OF POP
18-22mm
LVOT DIAMETER AVERAGE
20mm
LVOT and stroke volume (SV) and cardiac output (CO)
- LVOT can be used to calculate cardiac output and stroke volume using doppler method
cross sectional area formula
- LVOT (D) ^2 x (1/4)PI = Cross Sectional Area (CSA)
stroke volume equation using doppler formula
SV = (1/4 PI) x D^2 x VTI
left ventricle internal diameter systole (LVIDs)
- measured when ventricle is smallest and valves are shut
- from posterior edge of IVS to anterior edge of the posterior wall
- machine will produce a linear EF (ejection fraction) calculation when complete
NORMAL LVIDs MEASUREMENT
20-38mm
left atrium dimension (LA)
- taken at end systole
- ratio to aortic sinus should be 1:1
- visually if either one looks large than the other it may be dilated
- from posterior border of the aortic root to the anterior border of the posterior LA wall
- lower gain helps this measurement
NORMAL LA SIZE MEN
<40mm
NORMAL LA SIZE WOMEN
<38mm
fractional shortening
- measurement of LV function
- a linear calculation that gives information about the systolic function of the heart
fractional shortening equations
FS = LVIDd - LVIDs / LVIDd x 100
NORMAL FRACTIONAL SHORTENING
25-47%
linear ejection fraction
- takes dimensions and extrapolates a volume from them
+ only works for basal layer need to have uniform motion - makes general assumptions
+ the EF is reasonably accurate if there are no regional wall motion abnormalities
+ assumes callipers are correctly placed and perpendicular to long axis of LV
estimation of EF - specific assumptions
- ventricle is a prolate ellipse shape (bullet)
- long axis length is twice the short axis width
- symmetric contractility
teichholz formula
- the machine calculates for you for a linear ejection fraction
teicholtz EF modified
[{EDV (end diastolic volume)^3 - ESV (end systolic volume)^3}
/ EDV^3] x 100
how to get EDV and ESV from a dimension
EDV = LVIDd ^3
ESV = LVIDs ^3 THEN CONVERT mm TO cm
+ not super accurate but close enough
NORMAL EF
> /= 55%
Right ventricular inflow tract view (RVIT)
- try sliding more lateral and angle towards right hip
- BOTH TV LEAFLETS MUST BE SEEN
- pap not well seen
- no 2D measurements taken in this view
- just looking at tricuspid valve
RVIT structures anterior to posterior
- Right ventricle
- tricuspid valve
- Right atrium
- coronary sinus
- IVC
right ventricular outflow tract (RVOT) view
- focus is the Pulmonary valve and the main pulmonary artery
- no 2D measurements in normal exam
LV mass
- the weight of the LV myocardium in grams
- uses epicardial volume minus the endocardial volume what is left is myocardial volume
- assumes normal ventricular geometry
- volume of LV walls x myocardial density = mass
LV mass index
- varies with body size can range from 150gm to 350 gm
-
LVMI
- LV mass indes indexes LV mass to BSA (body surface area)
LV mass / BSA
LVMI NORMAL FOR MEN
<115 g/m^2
LVMI NORMAL FOR WOMEN
< 95 g/m^2
relative wall thickness (RWT)
- calculation takes your measurements of the posterior wall and indexes them to the LV chamber size
RWT basic principle
- bigger chamber (bigger person) will have thicker walls naturally
- when walls hypertrophy or dilate this calculation becomes abnormal
RWT formula
2 x LVPW/LVIDd
NORMAL RANGE FOR RWT
0.22 - 0.42 mm
Chamber quantification guidelines
1 normal geometry =LVMI = 95(w) 115(m) & RWT = 0.42
2 concentric remodelling = LVMI = 95(w) 115(m) &
RWT > 0.42
3 concentric hypertrophy = LVMI > 95(w) 115(m) &
RWT > 0.42
4 eccentric geometry = LVMI >95(w) 115(m) & RWT = 0.42
+ 1 is normal
+ 2 has normal mass but thick walls
+ 3 has abnormal mass and thick walls
+ 4 has abnormal mass but normal walls
