Three-dimensional reconstruction of fine vascularity in ultrasound breast imaging using contrast-enhanced spatial compounding: in vitro analyses.
OBJECTIVE
Ultrasound image quality can be improved by imaging an object (here: the female breast) from different viewing angles in one image plane. With this technique, which is commonly referred to as spatial compounding, a more isotropic resolution is achieved while speckle noise and further artifacts are reduced. We present results obtained from a combination of spatial compounding with contrast-enhanced ultrasound imaging in three dimensions to reduce contrast specific artifacts (depth dependency, shadowing, speckle) and reconstruct vascular structures.


METHODS
We used a conventional ultrasound scanner and a custom made mechanical system to rotate an ultrasound curved array probe around an object (360 degrees, 36 transducer positions). For 10 parallel image planes, ultrasound compound images were generated of a flow-mimicking phantom consecutively supplied with water and contrast agent. These compound images were combined to form a volume dataset and postprocessed to obtain a sonographic subtraction angiography.


RESULTS
Image quality was significantly improved by spatial compounding for the native (ie, without contrast agent), and, in particular, for the contrast-enhanced case. After subtracting the native images from the contrast-enhanced ones, only structures supplied with contrast agent remain. This technique yields much better results for compound images than for conventional ultrasound images because speckle noise and an anisotropic resolution affect the latter.


CONCLUSIONS
With the presented approach contrast specific artifacts can be eliminated efficiently, and a subtraction angiography can be computed. A speckle reduced three-dimensional reconstruction of submillimeter vessel structures was achieved for the first time. In the future, this technique can be applied in vivo to image the vascularity of cancer in the female breast.
Hansen
Christian
C
Institute for High Frequency Engineering, Ruhr-University, Gebäude IC, 6/140 Universitätsstr. 150, 44801 Bochum, Germany. christian.hansen@rub.de
Hüttebräuker
Nils
N
Wilkening
Wilko
W
Ermert
Helmut
H
D016477:Artifacts; D001940:Breast / Q000098:blood supply*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement; D021621:Imaging, Three-Dimensional; D019047:Phantoms, Imaging; D016217:Ultrasonography, Mammary / Q000379:methods*
D003287:Contrast Media