The switch from Gd-DTPA to Gd-DOTA is not associated with decrease of the T1 signal intensity of the pallidus and dentate in a pediatric population.

BACKGROUND: The switch from the linear gadolinium-based contrast agent (GBCA) gadopentate dimeglumine (Gd_DTPA) to the macrocyclic GBCA gadobutrol is associated with a decrease of the T1 signal intensity (SI) in brain gray matter nuclei. The effects of the switch to other macrocyclic GBCAs are not yet established. PURPOSE: To explore the effects of switching from Gd-DTPA to the macrocyclic GBCA gadoterate meglumine (Gd-DOTA) in pediatric patients. MATERIAL AND METHODS: We measured the pallidus/middle cerebellar peduncle (MCP) SI ratio and the dentate/MCP SI ratio in pre-contrast sagittal T1-weighted spin-echo images in nine patients who had received ≥6 administrations of Gd-DTPA and then of Gd-DOTA, in 18 patients who had received ≥6 administrations of Gd-DOTA alone, and in nine age-matched controls without prior GBCA administrations. Serial assessment was performed in patients who switched from Gd-DTPA to Gd-DOTA. Finally, the rate of change of pallidal/MCP and dentate/MCP SI ratios between the first and last Gd-DOTA administrations was compared. RESULTS: The pallidal/MCP and dentate/MCP SI ratios were (P < 0.05) higher in patients with prior Gd-DTPA and Gd-DOTA administrations compared to the controls. After the switch, the pallidal/MCP SI ratio increased in nine patients and the dentate/MCP ratio in seven patients. The rate of change of pallidal/MCP SI ratio after Gd-DOTA was higher (P < 0.01) in patients who had previously received Gd-DTPA (mean 2.89 ± 2.6%) than in patients who had received Gd-DOTA alone (mean 0.53 ± 0.89%). CONCLUSION: T1 SI in gray matter nuclei does not decrease after switching from Gd-DTPA to Gd-DOTA. The switch effects from Gd-DTPA to each macrocyclic GBCA should be individually evaluated.

Vertebra plana: reappraisal of a contraindication to percutaneous vertebroplasty.

PURPOSE: We evaluated the efficacy of percutaneous vertebroplasty (PVP) in treating symptomatic vertebra plana, which is considered a relative contraindication to the procedure. METHODS: Out of 540 levels treated in 260 patients, we treated 40 patients (mean age: 74 years) with vertebra plana between T6 and L3 (37 osteoporotic and 3 metastatic levels). In most cases, the vertebra was accessed with fluoroscopic guidance from a single, transpedicular approach. All patients underwent a preliminary MRI examination, an immediate, post-procedure radiological examination, and a follow-up examination (mean duration, 6 months). RESULTS: Both immediate and follow-up examinations showed that the mean pain and physical disability scores were significantly reduced compared to the scores before treatment (p ≤ 0.001). No complications occurred during the procedures. In 23/40 cases, asymptomatic intradiscal cement leakage occurred. Posterior or perivertebral leakage never occurred. In most cases, an intravertebral cleft was present, and we filled it with polymethylmethacrylate, which healed the pseudarthrosis. Partial vertebral height was restored in 7 cases. In 6 cases, a new fracture occurred between 1 and 3 months at a different level from the treated level. CONCLUSION: Our preliminary results showed that PVP was a safe, effective treatment for symptomatic vertebra plana; thus, it should not be discounted for this group of patients. In most cases, the procedure was favored by the presence of an intravertebral cleft that appeared to contribute to minimizing the risk of posterior cement leakage. Filling the cleft with polymethylmethacrylate allowed intravertebral stabilization.

Effects of hyaluronan on free-radical formation, corneal endothelium damage, and inflammation parameters after phacoemulsification in rabbits.

Free-radical formation may play a role in postoperative complications of phacoemulsification (e.g., corneal endothelium damage from mechanical injury). The present experiments were aimed at investigating whether different molecular weight ranges (2000-2600, 2600-3200, or 3200-3800 kDa) of hyaluronan may influence free radical formation, corneal endothelium damage, and inflammation parameters after phacoemulsification in the rabbit eye. The viscoelastic substance was injected in the anterior chamber of rabbits' eyes before phacoemulsification, at a 2.5% concentration. The formation of free radicals was determined by adding luminol to the irrigation media and measuring the chemoluminescence in eyes. The corneal endothelial damage was evaluated by measuring the corneal central thickness by pachimetry. The inflammation parameters were measured by calculation in aqueous humor of peak levels of leukocytes and prostaglandin E(2) (PGE(2)) and evaluation in uveal tissue of myeloperoxidase activity. Hyaluronan decreased by about 58-60% free-radical formation during phacoemulsification, reduced by about 76-80% modifications in mean corneal thickness and by about 54-61% the corneal endothelial cell loss in all molecular weight ranges used. No difference was found among various molecular weight ranges. The highest molecular weight range showed to be more potent than the lowest range for reduced number of inflammation cells and level of PGE(2) in aqueous humor. Thus, hyaluronan reduces free-radical formation, exerts protection on the corneal endothelium and exerts anti-inflammation properties after phacoemulsification in rabbits. The latter effect seems to depend on the molecular weight of the substance.