Prospective comparison of magnetic resonance sialography and digital subtraction sialography

We sought to compare the diagnostic utility of magnetic resonance sialography (MRS) and digital subtraction sialography (DSS) in patients with suspected sialolithiasis or sialadenitis. Sixteen consecutive patients (4 female and 12 male, mean age 51+/-16 years) with suspected sialolithiasis or sialadenitis underwent DSS by a standard technique and MRS. MRS was obtained with a T2-weighted single-shot TSE sequence (TR/TE 2800/1100 msec, acquisition time 7 seconds) using a quadrature head (n = 16) and a surface coil (n = 8). Nineteen symptomatic glands were investigated with DSS: eight submandibular glands in 6 patients (two bilateral) and unilateral parotid glands in 11 patients. MRS was always carried out to visualize gland ducts bilaterally. The ductal system was visualized in all glands examined by MRS. DSS depicted the ductal system in all 11 parotid glands, but only 4 of the 8 submandibular glands (50%). Sialolithiasis was diagnosed in three cases (one parotid, two submandibular glands) by MRS and in two cases by DSS. DSS demonstrated tertiary branching ducts and MRS secondary branching ducts. MRS is able to visualize the ductal system of the parotid and submandibular gland noninvasively and is thus not dependent on successful cannulation of the orifice of the ductal system. Our preliminary data indicate that MRS is useful for diagnosing sialolithiasis. MRS allows diagnosis of sialadenitic changes, but DSS achieves a better diagnostic performance due to higher spatial resolution.