Ultrasonographic examination of both stifle joints of five clinically and radiographically normal adult dogs was performed before and after surgical transection of the cranial cruciate ligament (CrCL). At pre- and postsurgery, the hyperechoic patellar ligament and the infrapatellar fat interfered with sonographic visualization of the CrCL. When the stifle joint, however, was imaged via dynamic intra-articular saline injection, the hyperechoic ligament was visualized because of the separation of the infrapatellar fat and the CrCL and the contrasting effect of anechoic saline. When the stifle joint was imaged by real-time scanning after the transection of the CrCL, flutter of the ligament and an anechoic area between the bone and the CrCL were identified. The increased diameter of the ligament and the increased thickness of the joint space were identified as well. Ultrasonographic examination via dynamic saline injection into the joint space has potential as a diagnostic tool for assessing CrCL rupture.

Ultrasonographic imaging of the canine external ear canal, tympanic membrane, and tympanic bulla was described in five healthy beagle dogs before and after infusion of saline into the ear canal. Saline served as an acoustic window. With this method, the external ear canal, and tympanic bulla were visible in the same imaging plane and the integrity of the tympanic membrane could be evaluated indirectly by confirming an intact tympanic membrane, which appeared at the end of the ear canal as a hyperechoic line with reverberation. Experimentally, perforated tympanic membrane could be evaluated by identifying anechoic saline in the tympanic bulla lumen. The air and fluid-filled tympanic bulla were also visualized. Ultrasonography with saline as an acoustic window appears to be helpful for the evaluation of the external ear canal, tympanic membrane, and tympanic bulla and it may have the potential to be a useful clinical tool in evaluation of integrity of the tympanic membrane.