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Diagnostic ultrasound ( PDFDrive )

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e6

APPENDIX

Ultrasound Artifacts: A Virtual Chapter

Increased Through Transmission

Increased through transmission occurs when an object (such as

a cyst) attenuates the sound waves less than the surrounding

tissues.

Click here to an explanatory video of increased through

transmission (Video A.5).

FIG. A.13 Increased Through Transmission. The hepatic parenchyma

distal to the cysts is falsely displayed as increased in echogenicity (arrows)

secondary to increased through-transmission artifact.

–0 dB

Gain compensated

–10 + 10 dB +10–3 = +7 dB

–20 + 20 dB +20–13 = +7 dB

FIG. A.12 Increased Through Transmission. The cyst attenuates

7 dB less than the normal tissue, and time gain curve correction for

normal tissue results in overampliication of the signals deep to the

cyst, producing increased through transmission of these tissues. 2

(See Chapter 1, Fig. 1.31C.)

FIG. A.14 Increased Through Transmission. Nabothian cysts show

both increased through transmission behind the cysts and edge

shadowing at the margins of the cysts. 4 (See Chapter 15, Fig. 15.7C.)

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