Comprehensive Radiographic Pathology: Chapter 2: Specialized Imaging Techniques Flashcards
When radiologists interpret images, they use a common terminology called _______ ________.
Terms used to describe imaging features:
-Location -Size -Density -Structure -Shape -Demarcation -Perfusion -Integration
a noninvasive imaging modality that uses high-frequency sound waves produced by electrical stimulation of a specialized crystal.
uses specially designed x-ray tubes to provide high quality images of the breast.
Mammo image creation
mammo ionizing radiation- x-ray attenuation of breast tissue
mammo image receptor
mammo digital plate or analog system
mammo image descriptors
same as used for General x-ray
ultrasound is a ______-sectional imaging technique.
1. Uses no radiation. 2. Real-time examination possible. 3. Units are mobile. 4. Has high sensitivity and specifically in certain situations. 5. Low cost 6. Availability 7. Ability to differentiate cystic, solid, and complex tissues
ultrasound image creations
transducer production of multi-frequency sound waves
ultrasound image receptor
Transducer receiving echoed signal
ultrasound imaging descriptors
Anechoic hyperechoic and hypoechoic isoechoic
(dark region) Echo free tissue or structure or lacking a signal
lighter shade and darker shade comparison of echo intensities for adjacent tissues
hyperechoic (lighter shade) and hypoechoic (darker shade)
(same shade) two structures that have the same echogenicity
produces cross-sectional tomography images by first gaining a slice of tissue from multiple angles with a collimated x-ray beam when calculating a relative linear attenuation coefficient representing the amount of radiation absorbed in the tissues for the various tissue elements in the section and finally displaying the commuted reconstruction as a gray-scale image on an Imaging monitor.
CT uses radiation to produce _______ _______ ________
____________ techniques are available. Adjust grayscale and brightness - window and level 3-D images
Scan times are very _______. CT enables imaging of all _______ _______ and _________.
efficient body systems and organs
CT image creation
Collimated x-ray beam attenuation detection
CT image receptor
Detectors receiving the attenuated signal
CT image descriptors
CT number (Hounsfield number) highest CT number is 1000 lowest CT number is -1000 window width window level
reflects the attenuation of a specific tissue relative to water which equals 0
CT number (Hounsfield number)
reflects bone (appears White)
highest CT number is 1000
represent air (appears black)
lowest CT number is -1000
spiral continuous motion
grayscale contrast scale
midpoint or Center of total number of densities
enhancing brightness intensity
maximum intensity projections(MIPs)
enhancing lowest intensities(colonoscopy)
minimum intensity projection(MiniIPs)
3D rendering demonstrating the surface or selected structures
shaded surface rendering and volume rendering
technique taking all the raw CT data density information and using them to stimulate three-dimensional images
volume rendered Imaging
demonstrates internal structures for virtual bronchoscopy or colonoscopy
Magnetic renaissance imaging (MRI)
a strong magnet producing radio frequencies at specific intervals and receives a return signal to produce an image
How are magnetic Resonance Imaging(MRI) images attained?
Images are obtained by placing the anatomic part in a strong static magnetic field and directing a radiofrequency (RF) pulse of a specific frequency at the area.
refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current -commonly in the 1 to 100-megahertz range- and their effect upon a body is potential heating of tissues in MRI
radio frequency pulse(RP)
What is the MRI process?
This process induces hydrogen atoms (protons) to alternate between high-energy and low-energy states by absorbing and then releasing, or transferring, energy.
What is functional MRI?
a brain imaging technique that reveals both brain structure and brain activity more precisely and rapidly than a pet scan. allows the localization of specific regions of the brain that correspond to various functions
MRI is the modality of choice for ________________________, ______, and ____________________.
This is the modality of choice for imaging the CNS, spine, and many musculoskeletal conditions.
What is an advantage of using MRI imaging?
Excellent soft tissue resolution and differentiation of tissue differences are obtained through a variety of pulse sequences.
What is the disadvantage of using MRI imaging?
Scan times are longer. -This increases difficulty in imaging some organs. -Some patients have difficulty with claustrophobia.
MRI image creation
radiofrequency pulses emitted to change hydrogen atom energy states
MRI image receptor
Receiver coil to detect energy changes to relaxation times
MRI pulse sequence
T1-weighted T2-weighted Fat suppression Susceptibility waited Diffusion weighted
High signals(bright) include fat. subcutaneous Hemorrhage, melanin, and slow-flowing blood, and IV contrast equilibrium high-energy protons return to the low energy state
High signals(bright) include water; lower signal intensity (intermittent to dark) include muscle and soft tissue; low signal intensity(dark) may indicate cortical bone, calcium, air, or fast-flowing blood(no signal) the image relies on local dephasing of spins
fat suppression MRI
differentiates fat from contrast material to highlight vascular structures require "saturation or full magnetization" on the T1 sequence to ensure a large contrast difference between fat and water
susceptibility weighted MRI
extremely sensitive to products that creates changes in magnetic susceptibility low signal intensity(dark); hemorrhage, calcium
diffusion weighted MRI
High signal intensity(bright) where random movement of water is restricted; stroke, liver lesions
relies on the movement of molecules and random thermal motion
used in conjunction with diffusion Imaging also relies on Fast scanning techniques and Rapid infusion of an intravenous contrast agent to visualize that transmit time of blood through the specific area
using radiopharmaceuticals to produce ionizing radiation that protects by gamma camera to produce an image
How does nuclear medicine work?
Nuclear medicine requires the patient to ingest or be injected (IV or IM) with a radiopharmaceutical that emits radiation.
a drug that is tagged to emit ionizing radiation
How are nuclear medicine images created?
Images are created by measuring the signals radiating from the patient.
What is an advantage of nuclear medicine?
This allows for visualization of physiologic processes. It detects some diseases earlier than other modalities.
a sodium iodide crystal detects ionizing radiation emitted from the patient
The gamma camera has a ________ made of lead that contains multiple parallel channels. These channels only allow rays that are perpendicular to the camera to pass and be detected while attenuating those that are not.
single photon emission computed tomography (SPECT)
gamma camera moves around the patient and detects the gamma rays produced by the radiopharmaceuticals
SPECT is an aspect of ________ imaging. It uses the same _______________.
SPECT is an aspect of NM imaging. It uses the same radiopharmaceuticals.
SPECT camera has the ability to ______ independently around the patient.
SPECT camera has the ability to rotate independently around the patient.
A computer uses the data to reconstruct _______________ images very much like CT or MRI. Images can be __________, __________, or ___________ plane.
A computer uses the data to reconstruct 3D sectional images very much like CT or MRI. Images can be transverse, coronal, or sagittal plane.
NM and SPECT image creation
radiopharmaceuticals that emit gamma radiation
NM image receptor
gamma camera that detects gamma radiation emitted from patients
SPECT image receptor
rotating gamma cameras for multiplanar gamma radiation collection
NM and SPECT Imaging descriptors
hot spots and cold spots
NM and SPECT hot spot
increases uptake directly proportional to the emission of gamma radiation
NM and SPECT cold spots
reflection of decreased uptake directly proportional to the emission of gamma radiation
using a radiopharmaceutical that emits a positron that the moving Gamma camera to text to produce an image
positron emission tomography(PET)
How does PET imaging work?
PET uses a radionuclide tracer similar to a naturally occurring substance in the body, such as carbon, oxygen, nitrogen, or glucose.
How does PET image distribution work?
The imaging distribution of the tracer allows for demonstration of detailed metabolic activity of the area of interest.
What is PET Imaging useful for?
It is especially useful in oncology, cardiology, and neurology.
PET image creation
radiopharmaceutical that emits a positron; through the collection following annihilation two gamma rays are created
interaction produces two high-energy protons(gamma rays) and opposite directions(separated by 180 degrees)
PET image receptor
Two opposite gamma cameras that detect gamma radiation simultaneously emitted from patient
PET Imaging descriptors
3D distinguishes diseased or necrotic tissue from healthy or normal tissue demonstrates tissue viability
three planes of colored images to demonstrate the biochemistry of tissue(biological map)
Fusion imaging combines _________ images with _________________ images.
Fusion imaging combines anatomic images with metabolic function images.
Fusion Imaging increases the accuracy of a ______.
Fusion Imaging increases the accuracy of a diagnosis.
equipment designed to image to modality simultaneously integrate the images
two types of Direct fusion imaging
Fusion Imaging image creation
- combination of two Imaging modalities(most common PET /CT) - integrated Imaging - direct Fusion
Fusion Imaging integrated Imaging
software creates images overlaying modality image data set
Fusion Imaging direct Fusion
simultaneous image creation
Fusion Imaging image receptor
two imaging receptors of modalities employed
Fusion Imaging Imaging descriptors
specific to Imaging modalities used to create fused images