Color Doppler imaging for vocal cord palsy.

BACKGROUND

Conventional techniques of laryngoscopy for vocal cord palsy can sometimes be difficult or impossible to perform, and B-mode real-time ultrasonography has been previously reported by the authors to be helpful in these situations. In some cases, however, B-mode ultrasonography can be inconclusive. We investigated whether color Doppler imaging can significantly improve vocal cord examination in these cases.

METHOD

Ten normal volunteers were examined using the Acuson 128XP/5 with a 7-MHz L7384 linear transducer. The thyroid cartilage was used as an acoustic window. Several distinct color flow patterns were observed with the subjects breathing quietly at rest, at the start of vocalization, and in prolonged phonation. Eight patients with hoarseness of voice were then examined by two separate observers in a double-blinded fashion. The first observer performed B-mode ultrasonography and color Doppler imaging, while the second observer performed indirect laryngoscopy and direct fiberoptic laryngoscopy.

RESULTS

Laryngoscopy was used as the standard for comparison. B-mode real-time ultrasonography correctly identified vocal cord palsy in three patients and normal vocal cords in one. The remaining four patients were reported as equivocal or normal. Color Doppler imaging correctly identified the problem in all eight patients.

CONCLUSION

Color Doppler imaging for vocal cord examination is more sensitive than B-mode real-time ultrasonography, and seems to be as accurate as laryngoscopy in determining vocal cord palsy or paresis.