Basic Imaging Principles and Transthoracic Echocardiography

Vocabulary practice flashcards covering acoustic windows, transducer orientations, cardiac planes, echocardiographic views, diagnostic measurements, and hemodynamics formulas based on lecture notes.

Footprint

The contact surface of the ultrasound transducer that touches the patient's skin.

Linear Phased Array Transducer

A dedicated cardiac ultrasound probe that produces a sector-shaped image, equipped with an orienting ridge (notch) positioned on the right side.

Acoustic Windows

Anatomical sites on the body where the transducer is positioned to image the heart without acoustic obstruction from bone or lung tissue: parasternal, apical, subcostal (subxiphoid), suprasternal, and supraclavicular.

Long-Axis Plane

An echocardiographic imaging plane oriented parallel to the long axis of the left ventricle that intersects the LV apex and the center of the aortic valve, aligned with the anterior-posterior diameter of the mitral annulus.

Short-Axis Plane

A series of imaging planes perpendicular to the long axis of the ventricle that produce circular cross-sectional views of the left ventricle, mitral valve, and aortic valve.

Four-Chamber Plane

An imaging plane extending from apex to base perpendicular to the short-axis view that divides the heart along the Z-axis, showing both ventricles and atria aligned with the medial-lateral diameter of the mitral and tricuspid annuli.

Two-Chamber Plane

An apex-to-base imaging plane perpendicular to the short-axis view, rotated midway between the long-axis and four-chamber views, that visualizes the left ventricle and left atrium.

Parasternal Long-Axis (PLAX) View

A standard echocardiographic view obtained with the patient in the left lateral decubitus position, placing the transducer in the left third or fourth intercostal space with the notch oriented between the $9$ and $11\text{ o'clock}$ position (pointing toward the right shoulder).

Aortic Valve Cusps in PLAX

The right coronary cusp (positioned anteriorly) and the non-coronary cusp (positioned posteriorly); the left coronary cusp lies lateral to the image plane and is not visualized.

LVOT Diameter

A linear measurement acquired on a frozen and zoomed PLAX 2D image during mid-systole, measured inner-to-inner to calculate aortic valve area.

E-Point Septal Separation (EPSS)

The minimal separation distance measured in M-mode between the maximal early diastolic opening point (E point) of the anterior mitral valve leaflet and the interventricular septum, normally measuring $0.2-1.2\,\text{cm}$.

EF Slope

The rate of early diastolic closure of the anterior mitral valve leaflet evaluated by M-mode echocardiography, with a normal reference range of $7-15\,\text{cm}$.

Aortic Cusp Separation (ACS)

The distance between the aortic valve leaflets in systole on M-mode, normally measuring $1.5-2.6\,\text{cm}$; values $< 1.5\,\text{cm}$ indicate aortic stenosis.

Right Ventricular Inflow Tract (RVIT) View

A parasternal view obtained from the 3rd or 4th intercostal space with the notch at $9-11\text{ o'clock}$ and the transducer tilted toward the patient's left shoulder, used to evaluate the right atrium, tricuspid valve, and right ventricle.

Right Ventricular Outflow Tract (RVOT) View

A parasternal view obtained with the notch at $9-11\text{ o'clock}$ and the transducer tilted toward the patient's legs to examine the right ventricular outflow tract, pulmonary valve, and main pulmonary artery.

Right Ventricular Systolic Pressure (RVSP) Formula

An equation calculating right ventricular systolic pressure from tricuspid regurgitation peak velocity: $\text{RVSP} = 4(V_{\text{tr jet}})^2 + \text{RAP}$.

Parasternal Short-Axis (PSAX): Mitral Valve Level

A transverse cross-section obtained by rotating the probe $90^\circ$ clockwise with the notch at $12\text{ o'clock}$ (pointing toward the chin) and without tilt, demonstrating the anterior and posterior mitral valve leaflets.

PSAX Left Ventricular Level Segments

The six myocardial segments evaluated at the papillary muscle level: anterior septal, anterior, anterior lateral, inferior lateral (posterior), inferior, and inferior septal.

PSAX Apical Level Segments

The four myocardial segments visualized near the apex by tilting the transducer toward the patient's right arm: anterior, lateral, inferior, and septal.

Apical Four-Chamber (A4C) View

An apex-to-base view obtained from the 5th or 6th intercostal space ($1\,\text{inch}$ lateral to the mid-clavicular line) with the notch at $2-3\text{ o'clock}$ and the footprint aimed at the right shoulder, demonstrating the LV, RV, LA, RA, and atrioventricular valves.

Simpson's Method

A 2D echocardiographic biplane summation-of-disks method applied in apical four- and two-chamber views to calculate left ventricular and left atrial volumes and ejection fraction.

Tricuspid Annular Plane Systolic Excursion (TAPSE)

An M-mode measurement of the longitudinal displacement of the lateral tricuspid valve annulus toward the apex during systole, used to assess right ventricular systolic function.

Tissue Doppler Imaging (TDI)

A pulsed-wave Doppler technique utilizing a $2\,\text{mm}$ sample volume placed $1\,\text{cm}$ from the mitral annulus to record myocardial velocities: systolic motion toward the apex ($S'$), early diastolic filling ($E'$), and atrial contraction ($A'$) away from the transducer.

Apical Five-Chamber (A5C) View

An apical view obtained by tilting the transducer anteriorly/superiorly (toward the legs) from the A4C view to bring the left ventricular outflow tract and aortic valve into view.

Apical Two-Chamber (A2C) View

An apical view obtained by rotating the transducer with the notch at $2\text{ o'clock}$ and no tilt, isolating the left atrium, mitral valve, and left ventricle (anterior and inferior walls).

Apical Three-Chamber (A3C) View

Also called the apical long-axis view; obtained by rotating the probe approximately $120^\circ$ counter-clockwise from the A2C view (notch at $9-11\text{ o'clock}$) to visualize the left atrium, mitral valve, left ventricle, LVOT, and aortic root.

Subcostal Four-Chamber View

An ultrasound view acquired beneath the xiphoid process with the patient supine and knees bent, optimal for assessing atrial septal defects (ASD) and guiding pericardiocentesis.

Sniff Test

A dynamic maneuver in which rapid inspiration decreases intrathoracic pressure to evaluate the collapsibility index and diameter of the inferior vena cava for estimating right atrial pressure.

Normal Right Atrial Pressure (RAP) Criteria

An estimated RAP of $3\,\text{mmHg}$ (range $0-5\,\text{mmHg}$) indicated by an inferior vena cava diameter $\le 2.1\,\text{cm}$ with greater than $50\%$ inspiratory collapse.

High Right Atrial Pressure (RAP) Criteria

An estimated RAP of $15\,\text{mmHg}$ (range $10-20\,\text{mmHg}$) indicated by an inferior vena cava diameter $> 2.1\,\text{cm}$ with less than $50\%$ inspiratory collapse.

Inferior Vena Cava (IVC) Sonographic Properties

A venous vessel that is thin-walled, collapsible with inspiration, non-pulsatile, and demonstrates a narrower lumen compared to the aorta.

Abdominal Aorta Sonographic Properties

An arterial vessel that is thick-walled, pulsatile, non-collapsible, and features a broader lumen than the inferior vena cava.

Suprasternal Notch (SSN) View

A scanning position above the sternum with the neck hyperextended, notch at $1-2\text{ o'clock}$, and footprint aimed downward, primarily utilized to diagnose aortic coarctation and dissection.

Modified Bernoulli Equation

A simplified mathematical equation converting peak blood flow velocity into a pressure gradient across an orifice: $P = 4(V_{\max})^2$.

Stroke Volume (Doppler Method)

The volume of blood ejected per heartbeat calculated using Doppler velocity-time integral and cross-sectional area: $\text{SV} = \text{CSA} \times \text{VTI}$.

Cardiac Output Formula

The total volume of blood pumped by the heart per minute: $\text{CO} = \text{SV} \times \text{HR}$.