Ultrasound Display Modes and Imaging Systems

Vocabulary flashcards covering ultrasound display modes (A, B, M, and B-Scan), imaging resolution, advanced imaging techniques, and data storage systems like DICOM and PACS.

A Mode

Also known as amplitude mode; a one-dimensional display similar to an oscilloscope where reflectors are represented as a series of spikes, with higher spikes representing stronger reflectors.

B Mode

Also known as brightness mode; a display where reflectors are represented by a series of dots, and the brightness of the dot indicates the strength of the reflector.

M Mode

Also known as motion mode; a display where the motion of dots is shown across the screen over time, used most commonly for heart imaging.

B Scan

A two-dimensional image formed by combining B mode with scanning motion, where dots represent depth and location within the body.

Static Scanning

Also called compound or contact scanning; a method where the Sonographer "paints" the image using a transducer on an articulated arm, offering a large field of view but no motion.

Real-Time Scanning

Also called Dynamic scanning; involves sweeping the sound beam to produce a series of frames in rapid sequence to create a motion picture effect.

Frame Rate

The number of images produced per second, measured in units of per second or $Hz$; the average is $30$ frames per second.

Flicker Threshold

The point up to $15$ images per second where the human eye can see flickering; above this rate, imaging appears moving or real-time.

Line Density

The number of scan lines used to create a single frame; greater density improves detail resolution but requires more time to create the frame.

Pulse Repetition Frequency (PRF) Formula

The relationship used to determine the frequency of pulses where $PRF = n \times LPF \times FR < 77,000$.

Range Ambiguity Constraint

A limit for penetration depth and PRF defined as $penetration (cm) \times PRF (kHz) < 77$; exceeding this value results in range ambiguity.

Temporal Resolution

The ability of a display to distinguish closely spaced events in time; it improves as the frame rate increases.

Coded Excitation

A technology that utilizes ensembles of pulses to generate a scan line, interpreted by a decoder to create higher intensity driving pulses and a more sensitive receiving system.

Harmonics

A type of filtering that removes the fundamental frequency to narrow the primary beam, eliminate grating lobes, and reduce artifacts.

Pulse Inversion

A technique using two pulses per scan line (where the second is the inverse of the first) to create harmonic imaging, improving detail resolution at the expense of temporal resolution.

Elastography

An imaging technique that estimates tissue stiffness, often called "imaging" palpation, used to evaluate masses and myocardium viability.

Fusion Imaging

The combined presentation of an ultrasound image with another imaging modality.

Tissue Doppler

A display mode used specifically to measure the movement of muscle.

Transparency Film

A type of recording film that requires chemical development in a darkroom and is ruined by light exposure.

Thermal Film

A recording medium commonly used in offices where prints are processed in approximately $10\,seconds$, allowing for adjustments in brightness and contrast.

Laser Film

A high-quality recording medium providing superior spatial resolution and between $256$ to $4096$ shades of gray.

Color Video Printer

A device that uses cyan, magenta, and yellow ribbons to heat-process images onto chemically treated paper, commonly for color Doppler images.

Video Cassette Recorder (VCR)

A device for recording motion; standard VHS tapes record $240$ lines, while Super VHS tapes can record $425$ lines.

Magneto-optical (MO) Disk

A rewritable and erasable storage disk used directly with an ultrasound unit, typically with a capacity such as $1.3\,GB$.

DICOM

Digital Imaging and Communication in Medicine; a standard established in 1985 for file formats, transfer, storage, and display of patient data across networks.

PACS

Picture Archiving and Communication Systems; a digital network for acquisition, storage, and transmission of medical images using a local area network (LAN).

Teleradiology

A PACS application involving the electronic transfer of images from one location to another to allow physicians to review exams remotely.