Intrathecal gadolinium: its time has come?

Association of deep white matter infarction with chronic communicating hydrocephalus: implications regarding the possible origin of normal pressure hydrocephalus. Idiopathic normal pressure hydroceph-alus may be a " two hit " disease: benign external hydrocephalus in infancy followed by deep white matter ischemia in late adulthood. T he article in this month's American Journal of Neuroradi-ology by Albayram et al (" Gadolinium-Enhanced MR Cis-ternography to Evaluate Dural Leaks in Intracranial Hypoten-sion Syndrome ") 1 reviews the authors' experience with intrathecal gadolinium administration for the detection of CSF fistulas resulting in spontaneous intracranial hypotension (SIH). In their report, the authors reviewed 19 patients with clinical SIH in whom 0.5 mL of gadopentetate dimeglumine diluted with 4 mL of saline was instilled intrathecally 1 hour before fat-suppressed T1-weighted MR imaging. They found CSF fistulas in 17 of 19 patients; 14 of the fistulas were subsequently confirmed, but in 3, the exact site of the fistula was not identified due to the gross extent of leakage by the time the MR imaging was performed. Ten patients had a single fistula, whereas 4 patients had multiple fistulas (2 tears in 3 patients and multiple tears in 1 patient). Of importance, 4 patients, all with meningeal diverticula, showed only paravertebral leakage without prominent epidural leakage. Although the authors did not routinely compare intrathecal MR myelography with CT cisternography, 2 patients did have both studies, and 1 of these showed leakage along a nerve root on MR myelography that was not visible by using CT myelography. Clinically, no patients were found to have an untoward reaction, behavioral changes, or evidence of toxicity at 24 hours and at 6 –12 months following the examination. Di Chiro et al 2 first used intrathecal gadolinium to detect intracranial CSF fistulas in Beagle dogs (Beagles apparently occasionally have spontaneous CSF rhinorrhea). Using gado-linium MR cisternography, they identified fistulas in 2 dogs that had been previously found to have CSF rhinorrhea by radioisotope cisternography. In 1999, Jinkins et al 3 administered cisternal gadolinium to rabbits, showing no behavioral effects, good cisternal contrast, but " gradual diffusion of the gadolinium into the cranial parenchyma. .. on the delayed MR studies (45 minutes– 6 hours), as revealed by progressive generalized enhancement of the brain. " Zeng et al, 4 from the same group, first piloted the technique in humans, showing excellent opacification and no gross behavioral changes following the instillation of 0.2 mL, 0.5 …