004 Urinary Tract Imaging - Basic Principles of Urologic Ultrasonography

Question 1

One cycle per second is known as 1 hertz (Hz). High-frequency ultrasonic transducers of ___ are used to image structures near the surface. Deeper structures require lower frequencies of ___. Axial resolution improves with increasing frequency, and depth of penetration decreases with increasing frequency.

Answer 1

One cycle per second is known as 1 hertz (Hz). High-frequency ultrasonic transducers of 6 to 10 mHz are used to image structures near the surface. Deeper structures require lower frequencies of 3.5 to 5 mHz. Axial resolution improves with increasing frequency, and depth of penetration decreases with increasing frequency.

Question 2

___ is the peak velocity minus the end-diastolic velocity over the peak systolic velocity. This is measured using the color flow doppler with spectral display, and is used to characterize renal artery stenosis, ureteral obstruction, and penile arterial insufficiency.

Answer 2

RESISTIVE INDEX is the peak velocity minus the end-diastolic velocity over the peak systolic velocity. This is measured using the color flow doppler with spectral display, and is used to characterize renal artery stenosis, ureteral obstruction, and penile arterial insufficiency.

Question 3

By convention, the ___ is used as a benchmark for echogenicity. By convention, the cephalad aspect of the structure is to the ___ of the image.

Answer 3

By convention, the LIVER is used as a benchmark for echogenicity. By convention, the cephalad aspect of the structure is to the LEFT of the image.

Question 4

Ultrasonography may produce injury due to mechanical effects caused by ___ or by ___.

Answer 4

Ultrasonography may produce injury due to mechanical effects caused by CAVITATION or by HEAT GENERATION.

Question 5

With the exception of some ___ stones, all renal and ureteral calculi may be detected by helical CT.

Answer 5

With the exception of some INDINAVIR stones, all renal and ureteral calculi may be detected by helical CT.

Question 6

The advantage of magnetic resonance imaging (MRI) is high-contrast resolution of soft tissue on ___. Fluid has a low signal, and appears dark on T1-weighted images; on T2-weighted images, fluid has high signal and appears bright. Gadolinium increases the brightness of T1-weighted images. Hemorrhages within a cyst results in a high signal on T1-weighted images.

Answer 6

The advantage of magnetic resonance imaging (MRI) is high-contrast resolution of soft tissue on T1-WEIGHTED IMAGES. Fluid has a low signal, and appears dark on T1-weighted images; on T2-weighted images, fluid has high signal and appears bright. Gadolinium increases the brightness of T1-weighted images. Hemorrhages within a cyst results in a high signal on T1-weighted images.