Magnetic resonance imaging contrast media in the subarachnoid space. A comparison between gadodiamide injection and gadopentetate dimeglumine in an experimental study in pigs.

RATIONALE AND OBJECTIVES: The authors studied the neural tolerance and contrast enhancement of a nonionic, gadodiamide injection (gadolinium [Gd]-DTPA-BMA), and an ionic, gadopentetate dimeglumine (Gd-DTPA), contrast medium in the subarachnoid space of the pig. METHODS: Sixteen experiments were performed in eight pigs. Lumbar and lateral C1-C2 punctures were performed. Ten milliliters of Gd-DTPA-BMA or Gd-DTPA with Gd concentrations varying from of 500 mmol/L to 0.625 mmol/L were injected, in four experiments via the lumbar route and in 12 experiments via the C1-C2 puncture. RESULTS: Four pigs injected via the C1-C2 puncture with a Gd concentration of 500 mmol/L had signs of somatomotor irritation and all were paretic after 24 hours. No somatomotor effects were observed in the other experiments, where lower concentrations of Gd were used. Marked enhancement of the cerebrospinal fluid with no visible signal differences was obtained with concentrations from 10 to 0.625 mmol/L. CONCLUSIONS: Both Gd-DTPA-BMA and Gd-DTPA are remarkably well tolerated in the subarachnoid space. In doses relevant for imaging purposes no adverse effects were seen.