Objective: To investigate the role of dynamic MRI in the diagnosis of
chordomas at the skull base. Materials and Methods: Six patients with
surgically proven chordomas of the skull base were examined with spin-
echo technique (repetition time/echo time 200ms/15ms). Serial imaging
was performed every 30 s for 240 s after a rapid injection of gadopene
tate dimeglumine (0.1 mmol/kg). The contrast material enhancement rati
o (CER) was analyzed. The CER was obtained for each region of interest
as follows: (Sn - So) x 100/Smax - So, where Sn indicates signal inte
nsity at each dynamic phase; So, signal intensity on the image obtaine
d before administration of contrast material; and Smax, maximum signal
intensity of all dynamic imaging. Results: All chordomas showed very
slow but steady increase of contrast enhancement with no peak within 2
40 s. The CERs of six cases at 30 s are 13 to 40 (mean value +/- stand
ard deviation: 22.8 +/- 10.2). Conclusion: Dynamic MRI may be helpful
in differentiating between chordomas and other tumors of the skull bas
e.