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Questions and Answers
What is the characteristic of negative contrast media?
Which of the following is an example of an invasive procedure in radiography?
What is the role of iodine and barium in radiography?
What is the modality of imaging used in hysterosalpingography?
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What is the characteristic of ultrasonography?
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Which water is used for in CT scan only?
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What is the formula for calculating CT numbers?
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What does the CT number of '0' represent?
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What is the unit of measurement for contrast on CT images?
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What is the range of density values expressed in CT images?
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What is the interpretation of iso-density to CSF on CT images?
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What is the indication of a CT scan?
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What is the limitation of CT scan?
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What is the safety precaution for MRI?
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What is the technique used in MRI?
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What is the reconstruction technique used in CT scan?
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What is the principle of the 3D ultrasound probe?
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What does the blue color in color Doppler ultrasound indicate?
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What is the main use of Power Doppler ultrasound?
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What is the Duplex method?
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What is the Triplex method?
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What is the limitation of ultrasound in imaging?
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What is the principle of CT scan?
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What is the advantage of using CT scan?
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What is the main use of ultrasound in interventional procedures?
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What is the characteristic of anechoic structures in ultrasound?
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Study Notes
Ultrasound
- Dynamic ultrasound involves continuous movement of the probe.
- Structures can be classified as anechoic (do not reflect sound), hypoechoic (reflect less sound), or hyperechoic (reflect much sound).
- B-mode dynamic ultrasound is a principle of three-dimensional (3D) imaging, with the only difference being an increase in thickness of the 3D probe.
Ultrasound Modes
- Doppler mode has three main modalities: color mode, pulse wave mode, and power Doppler.
- Two different associations of the above modalities are duplex and triplex.
- Color Doppler ultrasound provides information on the presence of blood flow, its orientation, and even the presence of turbulent flow.
- Power Doppler ultrasound is used to check for the presence of blood flow, but does not provide information about the orientation of the flow.
- Pulse wave Doppler mode shows the change of flow velocities in blood vessels during time.
Ultrasound Methods
- Duplex method combines B-mode to locate vessels and pulse wave or color Doppler to study the vessels.
- Triplex method combines B-mode, color Doppler or power Doppler, and pulse wave Doppler to study blood vessels.
Ultrasound Applications
- Ultrasound can be used to assist in interventional procedures, such as draining a collection or performing a biopsy.
- Ultrasound is good for exploring soft tissue and blood vessels, but has limitations in analyzing calcified bone and unexposed structures like the brain and spinal cord.
Computed Tomography (CT) Scan
- CT scans use X-rays and cross-sectional imaging, with acquisition done in the axial plane and reconstruction in the axial, coronal, and sagittal planes.
- Examination can be done with or without injection of contrast.
- Data acquisition can be done in two types of scans: contiguous scan and spiral or helical scan.
Radiography
- Contrast products can be negative (e.g., air, CO2), neutral (e.g., water), or positive (e.g., iodine, barium).
- Examples of invasive procedures include angiography, arthrography, barium swallow or enema, and cystography.
CT Scan Images Interpretation
- CT numbers are calculated by comparing the attenuation coefficients of water and tissue.
- The contrast on the images is expressed in Hounsfield units, with density ranging from -1000 to +1000.
- Hypo-density means a density closer to water, and can be classified into two groups: iso-density to CSF (water) and density lower than CSF.
- Iso-density to CSF means tissue rich in water, while density lower than CSF means fat or cholesterol.
- Hyper-density means a density closer to bone, and can be classified into two options: less than bone density (fresh blood, iatrogenic, or enhancement after injection) or iso or higher than bone density (ossification, calcification, or metallic structure).
CT Scan Post-Acquisition Reconstruction
- Reconstruction can be done in volumic reconstruction, MIP (Maximum Intensity Projection), and other types.
Indication of CT Scan
- CT scans are best for exploring all structures, but have limitations in indication based on the structure explored.
- Radiation is a concern in pregnancy and children, and contrast products may be impossible to use in certain cases.
Magnetic Resonance Imaging (MRI)
- MRI uses magnetic fields and has specific requirements before the exam, such as no mobiles or credit cards.
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Description
This quiz covers the basics of ultrasound imaging, including the characteristics of different structures and their interaction with sound waves. Learn about anechoic, hypoechoic, and hyper echoic structures and how they appear in ultrasound images.
