Intravenous digital subtraction angiography for patients with positional nystagmus.

Thirty cases of intractable positional vertigo were studied by means of digital subtraction angiography (DSA). Benign paroxysmal positional vertigo was not included. DSA allows real time digital subtraction of X-ray transmission data using an image intensifier and television system. Intravenous DSA (IV DSA) was used to compare blood vessel flow in the right and left vertebral arteries. Abnormal findings were noted in 27 patients, with 10 being affected on the left side, 7 on the right, and 10 bilaterally. Twenty-three patients had slight stenosis, and bending and kinking were observed in 17. DSA results were related to the 6 established types of positional nystagmus. DSA is, therefore, considered to be an important tool in the diagnosis and treatment of positional vertigo.