finals Flashcards
(77 cards)
1
Q
sophisticated imaging technique primarily used in the field of interventional radiology and diagnostic imaging to visualize blood vessels with great clarity
A
Subtraction angiography
2
Q
- useful for detecting vascular abnormalities
- enhances the visibility of blood vessels by digitally or manually removing (“subtracting”) non-vascular structures such as bones and soft tissues from the images
A
Subtraction angiography
3
Q
- (Nobel Prize winner 1949),
- 1927 developed the technique of contrast x-ray cerebral angiography to diagnose diseases, such as tumors and arteriovenous malformations.
A
Egas Moniz
4
Q
idea of subtraction images was first proposed by the Dutch radiologist ____ in the 1935, when he was able to produce subtracted images using plain films
A
Ziedses des Plantes
5
Q
Identifying aneurysms, stroke, or arteriovenous malformations.
A
Cerebral angiography
6
Q
Evaluating coronary arteries.
A
Cardiac angiography
7
Q
Assessing limb blood vessels
A
Peripheral angiography
8
Q
Visualizing kidney vasculature
A
Renal angiography
9
Q
ADVANTAGES OF SUBTRACTION ANGIOGRAPHY
A
- High-resolution images of blood vessels.
- Clear visualization without overlapping bone or tissue.
- Aids precise diagnosis and treatment planning.
10
Q
LIMITATIONS AND RISKS OF SUBTRACTION ANGIOGRAPHY
A
- Exposure to ionizing radiation.
- Risk of allergic reaction to contrast dye.
- Requires patient stillness to avoid motion artifacts.
- Less effective in cases of rapid patient movement or poor cardiac output.
11
Q
medical imaging technique that provides real-time x-ray images of the internal structures of the body, allowing physicians to observe dynamic processes such as organ movement, blood flow, and the positioning of surgical instruments.
A
Fluoroscopy
12
Q
invention of fluoroscopy dates back to
A
1896
13
Q
fluoroscopy was developed by
created the first fluoroscope—a device that used a fluorescent screen to visualize x-rays in real time.
A
Thomas Edison
14
Q
invention of the image intensifier in the ___ revolutionized the field by significantly increasing image brightness and reducing radiation dose, paving the way for the digital systems used today
A
1950s
15
Q
- traditional method of performing real-time x-ray imaging, widely used before
- foundational tool in radiology for dynamic studies— allowing clinicians to see inside the
body in motion, such as during swallowing, catheter placements, or angiography.
A
ANALOG FLUOROSCOPY
16
Q
heart of analog fluoroscopy is the
A
image intensifier
17
Q
- Converts incoming x-rays into visible light.
- Material: usually cesium iodide (csi).
- This light image corresponds to the x-ray shadow from the body.
A
input phosphor (scintillation)
18
Q
- Just behind the input phosphor.
- Converts the light photons into electrons via the photoelectric effect.
- Brighter parts of the X-ray image generate more electrons
A
photocathode
19
Q
- These focus and accelerate the electrons toward the output screen.
- The beam gets compressed, which increases brightness and sharpness.
A
electrostatic focusing lenses
20
Q
- Converts the accelerated electrons back into visible light.
- Material: Typically zinc cadmium sulfide.
- This light image is now much brighter than the original, thanks to image intensification (up to 10,000x).
A
output phosphor
21
Q
LIGHT IS CAPTURED BY A VIDEO CAMERA
* The bright light image from___OR__ the output phosphor is directed into an analog video camera (often a vidicon or CCD camera in later systems).
* The camera converts the optical image into an electrical video signal.
A
vidicon or CCD camera
22
Q
SIGNAL SENT TO MONITOR
* The electrical signal from the camera is transmitted to a ____
* The monitor displays the image in real time, showing the anatomy and movement inside the patient.
A
CRT monitor (cathode-ray tube).
23
Q
X-rays → Light
A
Input Phosphor
24
Q
Light → Electrons
A
Photocathode
25
Focuses/Accelerates Electrons
Electrostatic Lens
26
Electrons → Bright Light
Output Phosphor
27
Light → Video Signa
Video Camera
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Video Signal → Image on Screen
Monitor
29
Inside the image intensifier:
input phosphor
photocathode
electrostatic lens
output phosphor
video camera
monitor
30
- captures the X-ray image with a digital detector system, processes it with computer algorithms, and displays it on high-resolution monitors.
- allows for real-time subtraction, dynamic recording, and archiving of images for later review
- integration of image enhancement, motion correction, and dose reduction techniques makes it both safer and more effective.
DIGITAL FLUOROSCOPY
31
Component of Digital Fluoroscopy
xray tube
flat panel detector / digital ir
patient table
digital image processor (computer system
control console
high-resolution monitors
xray generator
c-arm or u-arm (optional)
image storage system (PACS)
32
Generates X-rays that pass through the patient.
X-ray Tube
33
Captures X-rays and converts them into digital signals (replaces image intensifier).
Flat-Panel Detector / Digital Image Receptor
34
Specialized table that can move and tilt to position the patient accurately.
Patient Table
35
Processes the raw data into usable images; applies filtering, subtraction, and enhancement.
Digital Image Processor (Computer System)
36
Interface where the radiologist or technician operates the machine and adjusts settings.
Control Console
37
Displays live and recorded images with high clarity and detail.
High-Resolution Monitors
38
Supplies high-voltage power to the X-ray tube and controls exposure parameters.
X-ray Generator
39
Movable arm that holds the X-ray tube and detector, providing flexible angles.
C-arm or U-arm (optional)
40
Stores images digitally for future access and comparison.
Image Storage System (PACS)
41
- also known as a digital image receptor, is one of the most transformative components in modern digital fluoroscopy, effectively replacing the traditional image intensifier and video camera system.
- primary function is to capture X-rays that have passed through the patient and convert them directly into digital signals, which are then processed to produce real-time fluoroscopic images.
flat-panel detector (FPD)
42
both materials used in flat-panel detectors,
but they differ in how they convert X-rays
into usable signals.
scintillator
photoconductor
43
(like cesium iodide) is used in indirect detectors and works by converting incoming X-rays into visible light, which is then turned into an electrical signal by a photodiode
scintillator
44
(like amorphous selenium) is used in direct detectors and converts X-rays directly into electrical charges without producing light
photoconductor
45
X-rays → Light → Electrical signal
CsI (scintillator) + a-Si (photodiode)
General digital radiography, fluoroscopy
Indirect FPD
46
X-rays → Electrical signal
a-Se (photoconductor)
Mammography, high-resolution needs
Direct FPD
47
Absorbs incoming X-rays and converts them into either light (indirect FPDs) or electric charge (direct FPDs).
x-ray absorber layer
48
Indirect FPDs: Light from the scintillator is captured by
photodiodes (usually made of amorphous silicon).
49
X-rays are directly converted to electrical charges by the photoconductor (usually selenium).
Direct FPDs
50
* A grid of tiny electronic switches located under each pixel.
* Controls the readout of the signal (light or charge) from each pixel and transfers it to the image processor.
* Enables rapid, pixel-by-pixel image data transfer.
thin-film transistor (tft) array
51
- used in flat-panel detectors to help read and transfer the image data
- act like gates, allowing the signals to be collected in an orderly way to form a clear digital image
thin-film transistor (TFT)
52
advantages of FPD
superior image quality
digital workflow integration
reduced radiation dose
compact design
53
limitations of FPD
cost and maintenance
lag and motion blur
limited dynamic range in some systems
radiation scatter sensitivity
54
- introduced by Ziedses des Plantes, is a technique by which bone structure image is subtracted or cancelled out. From the film of bones and opacified vessels, leaving an unobscured image of the vessels.
- fully define all vessels containing contrast material and at the same time eliminate the confusing overlying bone images.
- can be applied in all forms of angiography. Wherever the vessels are super imposed in the bone structure.
photographic subtraction
55
matching one image over another so that bony landmarks are precisely superimposed
Registration
56
reverse tone duplicate of radiographic image, showing changed to white and white to black.
Reversal film or mask film
57
film showing bone structures only, with no patient motion between black it and subsequent contrast studies. For these reasons zero film is exposed just before contrast medium is injected into vessels.
Zero film or scout film
58
radiographic image obtained with the contrast media induced in the patient
Series film
59
FIRST ORDER SUBTRACTION PROCEDURES:
Take scout film
The scout film is reversed using contact printer to obtain the reversal mask film
Take series film
Finally register the reversal mask film and series film together with blank film to obtain the final film
The process cancels out bony structure and reveals the anatomy of interest which appears in black.
60
Shows bones, soft tissues (no contrast)
Scout
Scout Film
61
Opposite tones of scout film
Reversal
Negative Mask Film
62
Shows bones + contrast-filled vessels
Series
Contrast Film
63
Match structures precisely
Registration
Align Films
64
Shows vessels only (bones canceled out)
Subtraction
Final Film
65
The imperfection can be corrected with second-order subtraction, which is developed by ___ and ____
Hanafee and Shinno.
66
SECOND ORDER PROCEDURES
Take a scout film
The scout film is reversed using contact printer to obtain the reversal mask film.
Take a series film
The series film is reversed using contact printer to obtain the reversal film.
Register scout film and series reversal film together with a blank film to obtain the second mask film.
Finally, register the mask film, series film, second mask film, and blank film to obtain the final film.
67
- Take pre-contrast X-ray.
- Shows bones and soft tissue (reference)
Scout Film (Zero)
68
- Reverse the scout film using a contact printer.
- Create negative for subtraction.
Reversal Mask Film
69
- Take post-contrast X-ray.
- Shows vessels along with bones/tissues.
Series Film
70
- Reverse the series film.
- Prepare for refined background subtraction.
Reversal Series Film
71
- Register scout film + reversal series film on blank film.
- Further cancels background structures.
Second Mask Film
72
- Register reversal mask film + series film +
second mask film + blank film.
- Isolate and display only the vessels.
Final Subtracted Image
73
- special hospital room where doctors perform minimally invasive tests and procedures to diagnose and treat cardiovascular disease.
- has special imaging equipment (fluoroscopy unit)
CATHETERIZATION LABORATORY
74
STRUCTURE LAYOUT AND DESIGN
- Should be located near the conventional imaging department, processing area and surgical room.
- Any observation windows should be lead treated glass.
- Should have a door dedicated for the patient to enter and exit, and should be large enough to accommodate a hospital bed.
- Door connecting to angiographic room to the control room should also be provided.
75
Must be big enough to accommodate all primary equipment and accessories and to accommodate emergency equipment in the event of life threatening situation. It should have a minimum of
500 square feet.
76
Ceiling height should be at least
10 feet
77
Walls should be shielded with ___ up to a height of ___
1 mm lead
7 feet
