Specialized imaging QNA

Common terminology that the radiologist uses to describe the image are the

imaging features.

The descriptor indicating the site where anatomic changes are evident is the

location.

The degree of vascularity of the abnormal tissues is described as the

vascularity (or perfusion) of the tissue

The most common imaging technique for diagnosing breast tissue today is

mammography (or ultrasound / screening mammography).

Beyond general radiography, the first new imaging modality was __ which produced images without the use of ionizing radiation.

Ultrasound

To visualize the fetus, today the safest modality is

ultrasound (or obstetric ultrasonography).

CAT stands for

computed axial tomography.

The first alternative to image the brain was provided by

computed tomography (CT)

What did computed tomography (CT) eventually replaced for brain imaging?

Pneumoencephalography

Scientists integrated strong magnets and radiofrequencies to develop

nuclear magnetic resonance (NMR)

nuclear magnetic resonance (NMR) Name today

magnetic resonance imaging (MRI)

Researchers developed a positron-emitting radiopharmaceutical to produce molecular images to create the newest modality

positron emission tomography (PET)

The modality that combines digital images using hybrid equipment or special software is

Fusion imaging

Sound waves produced by a transducer describe the imaging theory of?

ultrasound (or ultrasonography)

Sound waves passing through a water-tissue interface can produce reflections. These reflections are called

Echoes

In US, tissues transmitting sound waves easily are

anechoic (or sonolucent).

Strong reflections in US are called

hyperechoic or echogenic.

When two structures have the same echogenicity, the term

isoechoic

Doppler imaging is used to study

Blood flow

In Doppler imaging, color is used to represent the

Direction for flow and velocity for speed

Examples of acoustic barriers in US are

Air (or gas) and bone

Scanning using a narrow x-ray beam and computation of the attenuation coefficient, which is then displayed as a gray scale on the monitor, is

computed tomography (CT).

This reflects the specific tissue attenuation as relative to water in CT.

CT number (or Hounsfield unit [HU])

The highest CT number represents

Bone (+1000)

The areas that appear black on CT have the?

Lowest Ct number

High-resolution images indicate that the thin sections must be

1.5mm (or 2mm)

Multiple single-scan CT equipment has been replaced by

spiral (or helical) CT.

The newest CT scanners have ___ to produce 8 to 64 slices per scan rotation.

multidetector array systems

The seventh generation scanner collects data using a? and this is a multidetector scanner

Cone beam

Integrating all image data in CT by using software to produce 3-D images is

Volume rendering (or 3-D imaging / virtual reality) imaging

To enhance the CT image, ___ projections highlight the brightest pixels, improving the image.

Maximum intensity

To produce MR images, the technologist selects a pulse sequence that includes the RF pulse and its timing, which is usually represented by the

Repetition time and echo time.

The most commonly used pulse sequence in MRI is referred to as

Spin echo

Fat tissue, subacute hemorrhage, and highly proteinaceous material cause a high signal intensity that appears bright on

T1 weighted MR images

Blood flow is visualized as a

signal void (or black area / flow void)

To better demonstrate the blood vessels, ___ is administered for MR angiography examinations.

contrast agent (or gadolinium)

With the application of gradients, the random movement of water can be demonstrated in

diffusion-weighted imaging

To ensure a greater contrast difference between fat and water,

fat suppression (STIR) imaging

MR imaging visualizes blood transit time to help determine circulation in viable tissue.

Perfusion

Injecting a radionuclide and detecting the gamma radiation describe

Nuclear medicine

The dose of____is calculated on the basis of the specific half-life and decay rate.

Radiopharmaceutical (or radionuclide)

The decay of the radionuclide is detected for imaging purposes by a

Gamma camera

To gather data from the three-dimensional perspective, the use of a rotating gamma camera is used in

SPECT

SPECT meaning

Single-Photon Emission Computed Tomography

SPECT imaging is useful in evaluating

cardiovascular disorders, infections, tumors, and neurologic disorders, such as seizures and trauma.

The production of two high-energy photons in opposite directions is known as

Annihlation

PET is especially useful for imaging in

oncology, cardiology, and neurology.

In fusion imaging ____imaging is accomplished with the use of software and direct fusion imaging is a result of hybrid equipment.

Integrated imaging

A drug that emits radiation

radiopharmaceutical

Ability to combine images from different modalities into one image

fusion imaging

Allows for faster imaging and easy reformatting in the coronal and sagittal planes in CT

Helican or spiral scan

Produces images with high soft tissue resolution through the use of magnets and RFs

MRI

MRI meaning

Magnetic resonance imaging

Capable of producing images of the fetus without the use of ionizing radiation

Ultrasound

Compiles images to provide a 3D CT image, which is especially useful in visualizing the vascular system

Volume rendered imaging

CT numbers represent this value

Attenuation

Equipment designed to integrate multimodality images

Direct fusion

Gadolinium chelates are used to visualize the blood vessels

MR angiography

Has a gantry and x-ray tube, which rotates, producing cross-sectional images

Computed tomography (CT)

Hot spots indicate an increase in uptake that is directly proportional to the emission of gamma radiation

Nuclear medicine

Imaging especially useful in determining metastases in oncology patients to determine treatment

Positron emission tomography (PET)

In US, the term used when the organ tissues are very similar

Isoechoic

Localizes the specific regions of neurologic function of the brain

Functional MR

NM imaging with the addition of a rotating gamma camera

SPECT (single photon emission tomography)

On T1-weighted images, fat, subacute hemorrhage, and intravenous contrast material produce this signal

high signal intensity

The most common pulsing sequence(s) used in MRI today

T1/T2-weighted image

Radiopharmaceuticals are detected with this device

gamma camera

The time between the end of the last RF pulse and the point when the receiving coil listens for the signal

Echo time

The value given to the amount of attenuation in CT

CT number

3D rendering demonstrating the surface or selected structures

Computed tomography (CT)

Comparison of echo intensities for adjacent tissue

Ultrasound

Diameter or width and length (mm or cm)

Size

Heterogeneous (septate) or homogeneous (fluids)

Structure

High signals (bright) include fat, subacute hemorrhage, melanin, slow-flowing blood, and IV contrast

magnetic resonance imaging (MRI)

Indistinctly marginated (infiltration into surrounding tissue)

Demarcation

Nodular (tumor or lymph nodes) or reticular (resembling a net)

Shape

Relative to surrounding tissue (hyperdense or hypodense; radiolucent or radiopaque)

Density

Three planes of colored images to demonstrate the biochemistry of tissue (biologic map)

Positron emission tomography (PET)

Screening mammography images include

craniocaudal and mediolateral oblique projections

Imaging in ultrasound relies on a

transducer to receive and send sound waves

Air and bone are ______ in ultrasound.Helical scanning uses:

acoustic barriers

Helical scanning uses:

table movement during scanning , continuous x-ray exposure during scanning

Cross-sectional images produced by high-frequency sound waves is the modality known as:

Ultrasound (US)

In US, the transducer

records the changes in signal pitch and direction AND produces high-frequency sound waves

Tissue that is echo free or lacking in signal is:

anechoic

The CT number represents the

attenuation of specific tissue relative to water

The CT number representing bone (appearing white) is

+1000

The CT number representing Soft Tissue / Blood (appearing Gray) is

+20

The CT number representing Water (appearing Dark Gray) is

0

The CT number representing Fat (appearing Very dark Gray) is

-50

The CT number representing air (appearing black) is

-1000

High-resolution CT

requires thin section slices of 1.5 to 2 mm

In CT, the images that demonstrate the inside of a structure through reconstruction are called

virtual reality

The modality of choice for the spine and central nervous system is

MRI

The time it takes to play out the entire set of RF pulses before repeating is

Repition time

On MRI, blood flow is described as a

Signal void

Tissue suppression in MRI

creates a greater difference in tissue contrast is used in the neck, abdomen, and pelvis helps to differentiate tumor from normal tissue when the tissues are close in consistency

Molecular movement and random thermal motion are what ______ MR images rely on to produce an image.

Diffusion

Gamma radiation detected by a gamma camera is emitted by:

Radiopharmaceuticals

In the gamma camera, when the gamma rays interact with the crystals, they produce:

Light