CVS 106 Exam 3: M-Mode Ultrasound Terms & Definitions

M-mode (motion mode)

Produces one-dimensional information on a time-motion graph,

Displayed along a line representing the ultrasound beam direction ( provides a single line of information at a higher frame rate)

Temporal and spatial resolutions are higher because the focus is on only one of the lines from the 2D trace

The M-mode trace records

the depth and motion of echoes arising from intracardiac structures relative to time

Provides a 1D view and is used for fine measurements.

Why are Temporal and spatial resolutions higher

because the focus is on only one of the lines from the 2D trace

Three types of information can be obtained from the M-mode exam

Motion or time which is displayed on the horizontal axis/ X axis

Distance or depth, which is displayed on the vertical axis/ Y axis

Echo strength, which is represented as the brightness of structures appearing on the image display

( this echo brightness is directly proportional to the strength of the reflected echoes.)

The displayed image shows the structures as they change over time

The principle application of M-mode in an echo exam is?

in the assessment and measurement of cardiac chamber dimensions, valvular motion, and left ventricular systolic function.

What technique enhances M-mode?

accurate determination of linear dimensions

improves the quantification of chamber size

wall thickness

What is the optimum window selected for M-mode interrogation?

is the view in which the ultrasound beam passes perpendicular to the structures of interest

What is the principle advantage of M-mode over other modalities such as 2D imaging and Doppler?

is its superior temporal resolution

(the ability to precisely position moving structures from instant to instant. And is determined by the frame rate.)

What is the sampling rate (frame rate)for M-mode?

approx 1000-2000 frames per second,

far greater than 2D echo frame rate of between 30 -100 frames per second

Therefore M-mode provides valuable information regarding fast moving structures such as cardiac valves

It provides excellent interface definition, enhancing the accuracy of measurements

What is sampling rate (frame rate)?

The measurement of how quickly a number of frames appears within a second, which is why it's also called FPS (frames per second).

Multiple frames produced in rapid succession form the moving or real-time image we see on the ultrasound monitor.

Improving temporal resolution

Temporal resolution refers to the ability to precisely position moving structures from instant to instant.

Minimize depth of view

Use single focus

Narrow sector

Minimize line density

As temporal resolution improves, so does the image quality

What is the main determinant of temporal resolution ?

frame rate

What is temporal resolution?

the time to take the multiple measurements of the cross-section and then reconstruct the image

Which two factors determine temporal resolution?

propagation speed and depth of view have the greatest effect upon frame rate and temporal resolution.

What is the principle disadvantage of M-mode?

M-mode has limitations due to its one-dimensional nature and lack of spatial information.

It's also limited in deriving information about 3D structures.

The ejection fraction derived from M-mode is misleading when CAD alters the long (major) axis to short(minor) axis ratio.

optimize M-mode traces

Many instrument controls used to optimize 2D images can also be manipulated

Gains and TGCs

B –color maps

Sweep speed

Gains and TGCs

should be adjusted to ensure blood appears echo free and structures of similar acoustic properties are displayed at similar echo amplitudes.

B –color maps

can be applied in an attempt to enhance soft tissue differences

Sweep speed

which refers to the horizontal display rate is adjusted according to information required.

Example is if the heart rate is increased or decreased

The sweep speed defaults at 50mm/s

Higher sweep speeds such as 100mm/s -

fewer waveforms

Lower sweep speed such as 35mm/s -

more waveforms

The sweep speed defaults

at 50mm/s

Higher sweep speed

100mm/s will display fewer waveforms

Lower sweep speed

35mm/s will display more waveforms

sweep speed

Changes a number of cardiac cycles that can be is shown on the horizontal axis of the M-mode display.

incorrect M-mode plane

if the LV apex is tipped too far up on the parasternal long axis view

the LV M-mode will be oblique and the chamber dimensions will be inaccurate

correct M-Mode plane

the M-mode cursor must be perpendicular(right angle,two lines meet) to the septum and posterior wall of the left ventricle

What can be examined from Aortic- PSLA or PSSA view?

aorta

aortic valve

left atrium

From the Aortic -PSLA view the cursor is

directed perpendicular to the long axis of the aorta and through the aortic root at the tips of the aortic cusps

From the Aortic- PSSA view (aortic level) the cursor is directed

perpendicular through the short axis view of the aorta and left atrium

During systole, the aortic root move

anteriorly as left atrial volume increases with pulmonary venous return

The anterior and posterior walls of the aortic root move

parallel throughout the cardiac cycle

During diastole, the aortic root moves

posteriorly as the left atrial volume decreases as blood flows from the left atrium to the left ventricle

What does the motion of the aortic root throughout the cardiac cycle reflect?

left atrial dimensions

What happens on the onset of ventricular ejection, the aortic valve cusps?

snap open

RCC move anteriorly

NCC moves posteriorly

They remain open during left ventricular ejection

They lie parallel to the anterior and posterior walls of the aorta

What happens on the onset of diastole , the aortic valve cusps?

close and coapt( fasten or to close) in the center of the aortic root producing a singular linear echo

From the Q wave to the onset of ventricular ejection is a period known as pre ejection or isovolumic contraction time

Where does the left atrium lies directly?

behind the aorta

The anterior left atrial wall and posterior wall of the aortic root are anatomically separate structures BUT seen as ?

one structure on echo

Therefore, the anterior atrial wall follows the same motion of the posterior aortic root wall throughout the cardiac cycle

What does the posterior left atrial wall displays?

minimal motion and remains relatively "flat" during the cardiac cycle

From the PSLA MV M-MODE view the cursor is directed where?

perpendicular to the long axis of the left ventricle and through the tips of the mitral valve leaflets

From the PSSA view at the level of the mitral valve the cursor is positioned where?

perpendicular to the short axis view through the tips of the mitral valve leaflets ( in the PSSA view angling is imperative to make sure your at the tips of the leaflets)

During diastole, the mitral leaflets separate

widely with the AML approaching the IVS and the PML moving toward the LVPW

Comparing MV anterior and posterior leaflets

The larger anterior leaflet has a greater diastolic excursion than the smaller posterior leaflet, the anterior leaflet features a more prominent M configuration

When both MV leaflets close during ventricular systole, the leaflets should form a line called

the C-D line

Each characteristic point which forms the pattern of the AML throughout the cardiac cycle has been designated a letter

D-point

E-point

F-point

A-point

C-point

EPSS

D-point-

marks the position of the MV leaflets at the onset of diastole

D-END OF SYSTOLE

E-point-

reflects the maximal opening point of the MV leaflet due to early rapid filling phase (early diastole)

F-point-

is the most posterior position of the MV leaflet following the

E point (diastasis) valve drifts shut

MID DIASTOLIC CLOSURE

A-point-

reflects the point of reopening that occurs following

atrial systole/contraction 20% filling

C-point-

denotes the final position of the leaflet closure immediately prior to ventricular systole

closet of MV

EPSS-

E point septal separation, the distance between the IVS and E point

Where can the M-mode of the left ventricle can be assessed from?

the PSLA and the PSSA at the level of the papillary muscles and from the short axis subcoastal

The cursor is positioned perpendicular to the long or short axis of the left ventricle just past the tips of the open mitral valve leaflets

Wall movement during M-mode of the left ventricle

As the RV contracts during systole the ARHW moves posteriorly,

As the RV fills during diastole, the

ARHW moves anteriorly

The LV walls reflects changes in ventricular dimensions (expansion and contraction)

Following the onset of systole (isovolumic concentration),

the IVS moves rapidly posteriorly (down)while the LVPW moves anteriorly (up)

As early filling phase continues, the IVS continues to move steadily anteriorly while the LVPW move steadily posteriorly. This gradual anterior and posterior motion of the IVS and LVPW continues into diastasis

Following atria contraction, the IVS and the LVPW (to a lesser extent) move abruptly anteriorly and posteriorly

What can be mistaken as the posterior wall of the left ventricle?

The chordae tendineae

careful evaluation must be taken to visualize a minimal echo free space.

electrical events and mechanical events do not occur

at the same time.

For example atrial contraction on the M-mode trace will actually follow the P wave of the EKG and does not occur at the P wave

Why is the M-mode examination is the most difficult part of the echo examination to master when learning?

This is because of the need to align the ultrasound beam perpendicular to the structures transected by it

If a bump or notch is noted between the A and C point, this may be called

"B" bump.

The C - D line is where you would look for mitral valve prolapse.

Why is Correct cursor placement is crucial in the M-mode

examination of the left ventricle ?

because many quantitative

values are measured from this trace

M-mode of the left ventricle can be assessed from where?

PSLA and the PSSA at the level of the papillary muscles and from the short axis subcoastal

Where is the cursor is positioned on the M-mode of LV?

perpendicular to the long or short axis of the left ventricle just past the tips of the open mitral

valve leaflets

As the RV contracts during systole, where does the ARHW moves?

posteriorly,

As

the RV fills during diastole, where does the ARHW moves ?

anteriorly

The LV walls reflects changes in ventricular dimensions do to?

expansion

and contraction

Following the onset of systole, where does the IVS moves ?

rapidly posteriorly while the LVPW moves anteriorly

Normally, the LVPW peaks slightly after the peak of the IVS

As early filling phase continues, the IVS continues to move steadily

_______________ while the LVPW move steadily______________

anteriorly

posteriorly

This gradual anterior and posterior motion of the IVS and LVPW continues into diastasis

diastasis

middle phase of diastole

rapid filling phase and the active filling phase.

Following atria contraction, the IVS and the LVPW move abruptly where?

anteriorly and posteriorly

What can be mistaken as the posterior wall of the left ventricle?

chordae tendineae

but careful evaluation must be taken to

visualize a minimal echo free space.

M-mode for Plumonary Valve-

how many leaflets can be visualized from the

RVOT or PSSA AOV views

2 of the 3

but only one leaflet can be transected by the M-mode cursor at any one time

From the PSSA AOV view the cursor is usually directed

through the right cusp rather than through the left,

as the right is less likely to be overshadowed by lung tissue

What is the only structure of interest that is transected by the

ultrasound beam

cusp

During systole, the pulmonary valve opens and is seen to move

posteriorly

During diastole the cusps move

Anteriorly to their closed position

PV M-mode

A wave-

reflects the small posterior motion following atrial

contraction ( with atrial contraction an extra bolus of blood is ejected into the RV which slightly increases RV pressure which causes the PV to move posteriorly)

PV M-mode

B point-

denotes the small anterior motion occurring at the onset

of ventricular systole

PV M-mode

C point -

is the largest posterior motion immediately

following ventricular ejection ( the pulmonary valve abruptly opens)

PV M-mode

D point -

reflects the gradual anterior motion of the cusps

during ventricular ejection period ( as the RV pressure decreases, the pulmonary valve moves into the center of the root)

PV M-mode

E point-

refers to the closed position of the cusps upon

completion ( pulmonary valve snaps closed at the end of ejection)

PV M-mode

F point-

represents the slight posterior movement of the cusps during diastole and is the point immediately prior to atrial contraction and the next a point

pulmonary valve- M mode

the M-mode pattern produces one half of the box as

seen on the

aortic M-mode trace

When pulmonic stenosis is present, what wave is

increased ?

A wave

greater than 7mm.

When pulmonary hypertension is present, what wave

is decreased?

A wave

less than 2mm.

What may be seen when pulmonary hypertension is present?

Mid systolic notching or "flying W"

The best way to describe the evolution of the IVC diameter through the respiratory cycle is ?

to use M-mode

You will place the ultrasound beam on the cross-section of the IVC, activate M-mode.

You will see the structures on this beam line moving depending on the time.

It is then easy to measure the smallest and largest diameter of the IVC.

You will see the structures on this beam line moving depending on the time. It is then easy to measure the smallest and largest diameter of the IVC.

What is The assessment of the IVC ?

is the cornerstone of the patients'

volume status evaluation.

The interpretation of these

parameters will be different depending on the patient's respiratory mode

(spontaneously breathing or mechanical ventilation).

Spontaneously breathing patients

Patients with mechanical ventilation

Spontaneously breathing patients

In these patients, the IVC diameter and respiratory variation reflects the pressure in the right atrium (RA).

Patients with mechanical ventilation

In these patients, the presence of respiratory variations of the IVC will help you to predict responders to volume challenge and should be recorded for 3 to 4 cycles.

TAPSE

Tricuspid Annular Plane Systolic Excursion

Is a echocardiographic measurement that allows us to assess Right Ventricular function

Tricuspid annular plane systolic excursion (TAPSE), also

known

as tricuspid annular motion (TAM)

Normally during ventricular contraction the tricuspid

annulus descends toward

the cardiac apex as the RV

shortens

The degree of systolic descent of the tricuspid annulus is a reflection of RV longitudinal fiber shortening and overall RV systolic function

How is TAPSE measured?

by placing the M-mode cursor at the

lateral tricuspid annulus from the apical 4 chamber view

From the M-mode trace, how is TAPSE measured ?

as the vertical distance of the lateral annulus between end diastole and end systole

What is relatively an easy measurement for assessing

longitudinal RV systolic function?

TAPSE

it remains a one dimensional

measurement of RV function

What happens when the M-mode cursor is not placed

perpendicular to annular motion for TAPSE?

underestimation of TAPSE ,

and RV systolic function will occur

The normal rang for TAPSE?

1.6 cm

Measurements of Tricuspid Annular Plane Systolic Excursion

(TAPSE) in a normal individual

-24 mm

Measurements of Tricuspid Annular Plane Systolic Excursion in a patient with Pulmonary Hypertension

-9mm

MAPSE

Mitral Annular Plane Systolic Excursion

MAPSE

Purpose : assessing Left Ventricular function

could be used for critically ill patients

management of hemodynamic instability

assessing the ejection fraction

MAPSE

Limitation:

Inadequate m-mode

Regional wall motion abnormalities

Measures only longitudinal LV function

Where on the Leftside is MAPSE assessed with M-mode?

apical four-chamber view,

placing the m-mode cursor on the lateral mitral annulus.

The annular plane is identified on the m-mode as the first continuous line

immediately below the LV cavity

Where on the Right side of MAPSE does the measurement take place ?

from the end of diastole,

until maximal expansion in systole.