The evolution of velopharyngeal imaging.

Currently, functional visualization of the velopharynx requires tests that are either invasive (endoscopy) or that impart ionizing radiation (speech videofluoroscopy). The overall intrusiveness of endoscopy may limit its clinical utility, especially in young children. As a resut of growing awareness of the long-range effects of radiation exposure associated with X-ray imaging, radiographic research on subjects and studies not judged to be clinically necessary have been all but abandoned. The static nature of lateral radiographs precludes temporal assessment, and the two dimensionally of images derived from both of these diagnostic modalities may limit understanding of spatial anatomic relationships and may preclude quantitative analysis. The need for a noninvasive, rapid, and easily repeatable method for examination of the velopharynx has fomented the innovative application of existing technologies, especially magnetic resonance imaging. We present an updated overview of techniques for imaging the velopharyngeal mechanism, with a focus on residual velopharyngeal dysfunction after initial palatoplasty. We provide a comprehensive perspective of the role of currently available instrumentation, summarize the work in our center regarding the technological developments of magnetic resonance imaging, and speculate about future applications of magnetic resonance imaging systems for evaluation of velopharyngeal dysfunction. The limitations of each of these measures discussed are emphasized.