| 摘要 |
A combination of an ultrasonic scanner and an omnidirectional receive transducer for producing a two-dimensional image from the echoes received by the single omnidirectional transducer is described. Two-dimensional images with different noise components can be constructed from the echoes received by additional transducers. These can be combined to produce images with better signal to noise ratios and lateral resolution. Also disclosed is a method based on information content to compensate for the different delays for different paths through intervening tissue is described. Specular reflections are attenuated by using even a single omnidirectional receiver displaced from the insonifying probe. The disclosed techniques have broad application in medical imaging but are ideally suited to multi-aperture cardiac imaging using two or more intercostal spaces. An alternative method employs multiple transducers to increase the lateral resolution and reduce noise and includes using two or more active phased array transducers in the same scan plane. In this method the phase delays are computed such that the transducers operate as one larger phased array with a gap (or gaps) in the middle. Lateral resolution is determined primarily by the aperture defined by the end elements, wherein a gap necessitated by spanning the patient's ribs can be accommodated. Multiple slices using these methods can be combined to form three-dimensional images. |
