Purpose or Case Report:
1. Discuss benefits and limitations of different sonographic techniques
2. Provide phantom studies and clinical examples to demonstrate the effect of altering imaging parameters and sonographic techniques on both desired and undesired artifacts
3. Increase awareness of common errors in technique and provide recommendations to tailor the exam to the specific imaging question
Methods & Materials: Ultrasound is of critical importance in pediatric imaging. Recent advances, including harmonic imaging and spatial compounding, are now commonly utilized to improve overall image quality. Additionally, modern ultrasound units are equipped with features such as altering the speed of sound, 3D and large FOV. While these techniques offer many benefits, they may come at a cost, including reduction of desired artifacts, such as acoustic shadowing and enhancement. For this educational exhibit, we have constructed a phantom made of gelatin containing patient kidney stones and mimics of cysts. The effect of different imaging techniques on image quality and common artifacts are illustrated with the phantom and compared with clinical examples.
Results: Spatial compounding has been shown to reduce noise and speckle while increasing contrast and margin definition. This will be demonstrated on phantom and clinical examples, along with examples of its effect on ring down artifact, shadowing, edge shadowing and posterior enhancement. This is of clinical importance, as some of these desired artifacts are either less discernible or result in a different appearance with spatial compounding. The benefits of harmonic imaging will be shown, such as improved spatial resolution, decreased reverberation and increased contrast. Examples of the effect of harmonic imaging on shadowing, posterior enhancement and penetration will then be discussed and demonstrated. On newer units, resolution can be optimized by adjusting the speed of sound to match the imaged object. This will be demonstrated in phantom and clinical examples. As well, the effect of these imaging techniques and focal zone placement on twinkling artifact in color Doppler will be illustrated.
Conclusions: Ultrasound advances have led to increased image quality and a reduction in image artifacts. However, some of these artifacts are often desired and critical for diagnosis. An understanding of the effect of various sonographic techniques and parameters on both wanted and unwanted artifacts is critical to proper incorporation of these techniques into routine practice.