Calcium is a barrier to the penetration of ultrasound signal and causes characteristic 'acoustic shadowing
17.) They may have posterior acoustic shadowing
or no change in the echogenic appearance of the tissue posterior to the tumor.
Case 2: USG: Hyperechogenic image with posterior acoustic shadowing
S/O-Foreign Body in Abdominal Cavity.
US shows marked posterior acoustic shadowing
from an irregular, hypo-echoic density.
Whilst atelectatic lung does have areas of homogeneous echogenicity, it also has highly echogenic regions with distal acoustic shadowing
(due to the presence of air) (Figure 3).
Criteria Benign Appearance Shape Round, well-defined Margins Smooth, sharp, well-defined edges Echogenicity Isoechoic or slightly hypoechoic Internal echo pattern Homogeneous Acoustic shadowing
None demonstrated Calcifications Macrocalcifications Compressibility Compressible Criteria Malignant Appearance Shape Irregular, lobulated Margins Irregular, indistinct edges Echogenicity Markedly hypoechoic or black Internal echo pattern Heterogeneous Acoustic shadowing
Demonstrated Calcifications Microcalcifications Compressibility Noncompressible Shape
(1-3) Sonographic findings include single or multiple cysts, dilated ducts and highly echogenic foci with posterior acoustic shadowing
, representing fibrous tissue (Figure 4).
Ultrasound appearance of ascaris is reported in various studies as presence of long echogenic structure (linear or curved, single or multiple) with or without a central anechoic tube, mostly without acoustic shadowing
. (5,6,7) Varied appearances like "winding highway" or "parallel lines", "railway track"sign, "3 line" or "4 line" sign on longitudinal scan and doughnut or target sign, ring sign, bull's eye appearance on transverse scan had been reported in cases of ascariasis.
This configuration causes acoustic shadowing
and has a characteristic "laminated" sonographic appearance with parallel lines (FIGURE 2).
1c) revealed a right lower quadrant inflammatory mass with posterior acoustic shadowing
and surrounding loculated fluid collection.
A targeted left breast ultrasound at 11 o'clock, 5 cm from the nipple, underlying the area of a palpable abnormality, demonstrates an ill-defined hypoechoic mass with posterior acoustic shadowing
measuring 1.2 x 1.3 x 0.7 cm (Figure 3).
Sonography shows single or multiple poorly marginated hyopechoic lesions with or without distal acoustic shadowing