Analysis of refractive artifacts by reconstructed three-dimensional ultrasound imaging.
OBJECTIVE
Refractive artifacts are frequently encountered in clinical settings, and they have been analyzed on the basis of conventional two-dimensional (2-D) ultrasound (US) images, but this method is restricted to monoplane data and is limited by its inability to assess the three-dimensional (3-D) structure of refractive artifacts. The aim of this study was to evaluate the role of reconstructed 3-D US images in the analysis of refractive artifacts.


METHODS
The following representative refractive artifacts were analyzed on the basis of reconstructed 3-D US images: (a) a distorted image of a fine tube behind a cyst (balloon); (b) a deformed image of the bottom of a balloon; and (c) a duplication artifact due to the acoustic lens effect.


RESULTS
(a) A tube was imaged as a fine echogenic line with two points of sudden interruption, unlike a curved needle, which was imaged without interruption. (b) 3-D US allowed us to visualize the mode of deformity in the image of the bottom of a fluid-filled balloon in a water bath. When the acoustic velocity in the fluid was greater than that in the surrounding water, the bottom of the balloon appeared to be shrunken. When the acoustic velocity in the fluid was less than that in the surrounding water, the bottom of the balloon appeared to be swollen. (c) When we placed two pieces of white chicken meat in front of a fine needle, the needle was duplicated in the resulting image. In this case, the needle appeared to be vague and fuzzy. In this case, 3-D US did not add further information to the 2-D images.


CONCLUSIONS
Our study suggests that reconstructed 3-D US images provide a better understanding of the mode of refractive artifacts than do 2-D US images.
First Department of Internal Medicine, Akita University School of Medicine, Akita, Japan.
Michiko
M
Sato
Center of Diagnostic Ultrasound, Akita Red Cross Hospital, 222-1 Saruta Kamikitade, Akita, 010-1495, Japan. ishida@archosp-1998.com.
Hideaki
H
Ishida
First Department of Internal Medicine, Akita University School of Medicine, Akita, Japan.
Kei
K
Konno
Center of Diagnostic Ultrasound, Akita Red Cross Hospital, 222-1 Saruta Kamikitade, Akita, 010-1495, Japan.
Tomoya
T
Komatsuda
Center of Diagnostic Ultrasound, Akita Red Cross Hospital, 222-1 Saruta Kamikitade, Akita, 010-1495, Japan.
Kayoko
K
Furukawa
Center of Diagnostic Ultrasound, Akita Red Cross Hospital, 222-1 Saruta Kamikitade, Akita, 010-1495, Japan.
Mamiko
M
Yamada
Center of Diagnostic Ultrasound, Akita Red Cross Hospital, 222-1 Saruta Kamikitade, Akita, 010-1495, Japan.
Hitoshi
H
Yagisawa
First Department of Internal Medicine, Akita University School of Medicine, Akita, Japan.
Yasuo
Y
Yoshida
First Department of Internal Medicine, Akita University School of Medicine, Akita, Japan.
Sumio
S
Watanabe
2-D (two-dimensional); 3-D (three-dimensional); artifact; sound refraction; ultrasound