Ch. 19 - US: Understanding the Principles and Recognizing Normal and Abnormal Findings Flashcards
A tissue that reflects many echoes is said to be:
Echogenic (Hyperechoic) –> Usually depicted as bright or white on the sonogram.
A tissue that has few or no echoes is said to be:
Sonolucent (hypoechoic or anechoic) and is usually depicted as being dark or black.
Gallstones:
Characteristically echogenic and produce acoustical shadowing because they reflect most of the signal.
Biliary sludge:
Can be found in the lumen of the gallbladder and is often associated with biliary stasis.
–> May be echogenic - sludge does NOT produce acoustical shadowing like gallstones.
The typical appearance of … is a dilated calyceal system.
Obstructive nephropathy.
In medical renal disease:
Renal parenchyma becomes more echogenic (brighter) that the liver and spleen, the reverse of the normal echo pattern.
US is the screening study of choice when:
An asymptomatic, pulsatile abdominal mass is palpated.
MC MASS in the ovary:
A functional cyst.
Generally, uterine masses are more …, and ovarian masses are more … .
Uterine –> Solid.
Ovarian –> Cystic.
Follicular cysts and corpus luteum cysts are … of the ovary:
Functional cysts.
Functional cysts are characteristically:
- Well-defined.
- Thin-walled.
- Anechoic structures with homogenous internal fluid density.
- They may contain echogenic material if hemorrhage occurs into the cyst.
Non functional cysts of the ovary include:
- Dermoid cysts.
- Endometriomas.
- Polycystic ovaries.
Tumors of the ovaries:
- Most often arise from the surface covering and are either serous or mucinous.
- Most serous tumors + overwhelming number of mucinous tumors are benign.
Acute appendicitis:
Appendix may be blind-ending, aperistaltic tube with a diameter of 6mm or more.
Appendicitis - A fecalith is present in about … of cases:
1/3.
Most ectopic pregnancies are:
Tubal in location and occur near the fimbriated (ovarian) end.
An ectopic pregnancy can be effectively excluded:
If an intrauterine pregnancy is present.
An ectopic pregnancy can be effectively included:
If an extrauterine pregnancy is seen.
Most often, an ectopic pregnancy is diagnosed by a combination of:
Absence of an identifiable intrauterine pregnancy while the β-HCG rises above a certain level.
A molar pregnancy:
Is suggested by a uterine size that is disproportionately large for the dates of gestation and β-HCG levels in excess of 100.000 mIU/mL. (NORMAL –> 60.000mUI/mL).
Carotid stenosis begins to cause changes in the velocity of flow when there is greater than … narrowing of the lumen.
50%.
Sonographic evaluation for DVT of the leg is mainly based on the principle that:
Normal venous structures will be easily compressed and collapsed by the transducer, whereas veins harboring thrombi will NOT compress.
–> Also seeks to visualize the echogenic thrombus itself.
Uses of US during pregnancy:
- Fetal presence and gestational age.
- Fetal abnormalities and viability.
- Presence of multiple pregnancies.
- Placental localization.
- Amniotic fluid volume.
- Intrauterine growth retardation.
- Helping guide invasive studies like:
a. Amniocentesis.
b. Chorionic villus sampling.
c. Intrauterine transfusions.
Advantages of ultrasonography:
- No ionizing radiation.
- No known long-term side effects.
- “Real-time” images.
- Produces little or no patient discomfort.
- Small, portable, inexpensive, ubiquitous.