The mirror artifact is similar to the reverberation artifact. Mirror image artifacts (mirroring) can occur if the acoustical impedances of the tissue is too much different and the ultrasound is reflected multiple times on tissue layers. The echo detected does not come from the shortest sound path, the sound is reflected off an angle to another interface so that like a real mirror, the artifact shows up as the virtual object.
An empyema or lung abscess can be simulated by a mirror image artifact of a hepatic cyst. This liver lesion can appear like a lesion within the lung because the wave is reflected off the diaphragm back into the liver. The angle of reflection is equal to the angle of incidence. The sound pulse hits the interfaces within the liver lesion and is reflected back to the diaphragm once again with an angle of reflection equal to the angle of incidence and then back to the transducer.
Also by a pelvic ultrasound scan the sound can be reflected off the rectal air at an angle so that the deep wall of an artifactual cyst represents the mirror image of the inferior and anterior walls of the bladder. Mirror image artifacts can cause other strange appearances such as invasion of a transitional cell carcinoma through the bladder wall.
Also called Cross Talk.

(Z) The acoustic impedance is dependent on the density of the material in which sound is propagated through. When an ultrasonic wave crosses an interface between tissues with different acoustic impedance, the wave divides in 2 components, and the energy of the reflected components directly relates with the acoustic impedance.
The greater the impedance the more dense the material, and the greater the difference in acoustic impedance between two adjacent tissues the more reflective will be their boundary.
The acoustic impedance (the unit is 'Rayl') is the product of the sound velocity and the physical dense.
The acoustic impedance is very high between air or bone and other body tissues, therefore not enough energy crosses these interfaces, and no information can be collected from organs placed behind them.

See also Mirror Artifact, Reverberation Artifact, Cross Talk and Ultrasound Physics.

From Verathon Inc.;
'The BladderScan® is a portable, noninvasive ultrasound instrument that measures bladder volume. It is battery-operated, easy to use, and quickly provides accurate results. In less than five minutes, you can use the BladderScan® to obtain a precise reading of a patient's bladder volume. The BladderScan® supplies the information that caregivers need to diagnose, treat and manage urinary conditions.'

See also Urologic Ultrasound, Mirror Artifact, Pelvic Ultrasound, Transrectal Sonography and Ultrasonography.

From Verathon Inc.;
'The BladderScan® BVI 6100 is a handheld, noninvasive ultrasound instrument that measures bladder volume. It is easy to operate, so any staff member can scan patients quickly and accurately. To view ultrasound images from exams and print BVI 6100 exam results for patient records and reimbursement, just log on to ScanPoint®, Verathon Inc.'s (formerly Diagnostic Ultrasound Corp.) innovative online service. The BVI 6100 makes it easier to provide the best care for your patients.'

See also Urologic Ultrasound, Mirror Artifact, Pelvic Ultrasound, Transrectal Sonography and Ultrasonography.

From Verathon Inc.;
'The BladderScan® BVI 6300 Bladder Monitor is a handheld, noninvasive ultrasound instrument prescribed by the health care provider to enable patients to monitor bladder fullness on an ongoing basis. It is easy to use and quickly provides accurate results, so the patient can make informed decisions about when voiding is necessary.'

See also Urologic Ultrasound, Mirror Artifact, Pelvic Ultrasound, Transrectal Sonography and Ultrasonography.