Types of Imaging Questions and Answers
Since water is a good transmission of sound waves, they produces strong reflections which
appear dark on the screen. fluid-filled structures like cysts, bladders, and gallbladders appear
dark. If there is a stone in the gallbladder the sound waves become attenuated causing a
disturbance and the pathology will appear with variable intensity.
Hyperechoic or echogenic ✔️✔️appear light gray or white because of their strong reflections
such as stones, bones, and biopsy needles
Hypoechoic ✔️✔️these are structures that are not quite anechoic, but appear dark gray such as
the GI tract
Isoechoic ✔️✔️tissue that has the same ultrasonic appearance as that of the surrounding tissue
Ultrasound Vascular Studies ✔️✔️Can visualize
- Clots
- Stenosis
- Emboli
- Plaques
Most common areas: Carotids and lower extremities
Doppler Imaging ✔️✔️Doppler imaging produces the quantitative data. Add color to differentiate
the direction of the blood flow and velocity.
, Computed Tomography (CT) ✔️✔️CT is essentially scanning a slice of tissue from multiple angles
with a narrow x-ray beam then calculating a relative linear attenuation coefficient and
converting it to a grey scale image on a monitor.
Computed Tomography Limitations ✔️✔️- High dose of radiation
- Can require an intravenous injection of iodinated
contrast
_ More expensive than x-ray (less than MRI)
- Vascular imaging is becoming more common but
needs to incorporate more specialized training
due to the complexity of the protocols.
Magnetic Resonance Imaging (MRI) ✔️✔️a technique that uses magnetic fields and radio waves
to produce computer-generated images that distinguish among different types of soft tissue
MRI in a short statement is placing the body into a strong magnetic field and sending
radiofrequency pulses and receiving signals. Each time the RF energy is turned on and off, T1
and T2 happen where the proton is releasing energy and going back to its natural state. As that
happens the receiver coils read the signals and sent to the computer.
Magnetic Resonance Imaging Limitations ✔️✔️- Long scan time
- Sensitive to motion
- Noisy
- Claustrophobia
- Patient size limitations
- Expensive
- Requires highly trained technologists
- Difficult to monitor patients
- Ferrous materials and implanted devices