Coordination preference of Ga in hydrides.

Aluminum and gallium show some interesting differences in their coordination chemistry. Solid GaH3 is unknown, in contrast to solid AlH3. Ga equivalents of Li3AlH6, Na3AlH6, and other hydrides whose structure contain AlH(3-)6 ions, are unknown. We relate these differences to an instability of the hexacoordinated gallium moiety.

Iodixanol in paediatric gastrointestinal imaging: safety and efficacy comparison with iohexol.

Iodixanol (Visipaque) is a dimeric, non-ionic iodinated contrast medium that is isotonic with blood at all clinically relevant concentrations. Iodixanol was compared in a randomized, double blind, parallel group, phase III multicentre trial with a monomeric, non-ionic contrast medium, iohexol (Omnipaque), at two concentrations assessing safety, tolerability and radiographic efficacy during contrast enhanced gastrointestinal radiography examinations of children. 154 children entered the trial; 152 formed the safety population and 147 the efficacy population. All examinations were performed following standard departmental practice. Children were assigned into either a high or low concentration group (iodixanol, 150 mgI ml(-1) and 320 mgI ml(-1) vs iohexol, 140 mgI ml(-1) and 300 mgI ml(-1)). The primary outcome measure for efficacy was the overall quality of visualization, which was assessed using a 100 mm visual analogue scale (VAS). The secondary efficacy variables assessed were quality of contrast opacification, mucosal coating and overall quality of diagnostic information. Safety evaluation involved patient follow-up for at least 48 h. Taste acceptance was also assessed. There was no statistically significant difference between the two contrast media with regard to the primary and secondary efficacy variables assessed, although higher ratings were observed for iodixanol. The 100 mm VAS score overall was 86 mm for iodixanol and 82 mm for iohexol (95% confidence interval -2.56, 10.42). The frequency of adverse events was lower for patients receiving iodixanol. Adverse events, mainly diarrhoea, occurred in 12 patients (16.2%) in the iodixanol group and 28 patients (35.9%) in the iohexol group. This reached statistical significance (p=0.006). Overall, iodixanol is well suited for examinations of the gastrointestinal tract, giving good efficacy results and fewer adverse events than iohexol.

Diagnostic quality in endoscopic retrograde cholangiopancreatography: comparison between lodixanol and lopromide.

BACKGROUND AND STUDY AIMS: The contrast medium for endoscopic retrograde cholangiopancreatography (ERCP) must produce adequate images, whilst keeping the risk of complications to a minimum. There is a theoretical reason to suppose that a dimeric isosmolar medium may be superior to a monomeric hyperosmolar medium. We have compared two such media in a triple-centre double-blind randomized study on patients referred with a clinical indication for ERCP. PATIENTS AND METHODS: A total of 160 patients were randomly allocated to either lodixanol or lopromide. Assessments were made of the quality of images and the complications encountered. RESULTS: A total of 151 patients were evaluated. Apart from a trend towards better diagnostic quality for main pancreatic duct imaging with lodixanol, there were no differences between the two groups. The overall frequencies of adverse events were similar CONCLUSIONS: lodixanol is a safe and effective water-soluble contrast medium for ERCP, comparable to lopromide, but despite theoretical advantages lodixanol has no clear practical benefit.

Diagnostic quality in hysterosalpingography. Comparison between iodixanol and iotrolan.

PURPOSE: To compare the diagnostic quality and adverse events of the water-soluble, non-ionic, iso-osmolar, dimeric contrast media iodixanol and iotrolan in hysterosalpingography (HSG). MATERIAL AND METHODS: One hundred and twenty patients participated in a double-blind randomized parallel-group phase-III study. Questionnaires and patient interviews were used. Diagnostic quality was assessed using a visual analogue scale and the quality in specific regions was rated using a categorical scale. RESULTS: Overall diagnostic quality was equal for the two groups. There was no statistically significant difference between the two groups in diagnostic quality in the specific regions of interest. No differences between the contrast media were found with regard to adverse events. CONCLUSION: Both contrast media provided images of high diagnostic quality in HSG.

Iopentol (Imagopaque 350) compared with diatrizoate (Urografin 370) in cerebral CT. A clinical trial assessing immediate and late (7 days) adverse events and diagnostic information (visualization quality and Hounsfield unit measurements).

The non-ionic contrast medium iopentol (Imagopaque, Nycomed Imaging AS, Oslo, Norway) 350 mg I/ml was compared for safety and efficacy with the ionic contrast medium diatrizoate (Urografin, Schering AG, Berlin, Germany) 370 mg I/ml in a randomized, double-blind, parallel-group clinical trial in cerebral computed tomography (CT). The numbers of participating patients was 79; forty in the iopentol group and 39 in the diatrizoate group. Safety was evaluated by assessing the numbers of patients reporting immediate adverse events (up to 30 min after injection) and delayed adverse events (within 7 days after the examination). Efficacy was expressed as the quality of visualization of the cerebral lesions after injection of the contrast medium. In addition, Hounsfield units were measured pre- and post-contrast. No patient in either group experienced any serious adverse event. The frequency of patients with immediate adverse events was statistically significantly lower in the iopentol group (23%) than in the diatrizoate group (64%), p = 0.0003. Delayed adverse events were also significantly less frequent in the iopentol group (43%) than in the diatrizoate group (69%), p = 0.047. Patients in the iopentol group reported significantly less discomfort (53%), especially sensation of warmth, than patients in the diatrizoate group (92%), p = 0.0001. The intensity of adverse events and injection-associated discomfort seemed, in general, to be lower for patients in the iopentol group. No difference was found between the two contrast media regarding efficacy.

Delayed CT of the kidneys after iopentol (Imagopaque 350) injection in patients with normal renal function. An assessment of the gradual decrease in opacification over 32 h after injection.

The elimination of the non-ionic contrast medium iopentol (Imagopaque, Nycomed Imaging AS, Oslo, Norway) from the kidneys was investigated in adult patients with normal renal function referred for cerebral computed tomography (CT). Twenty-four patients were included in the study. Each patient was given one intravenous injection of 50 ml iopentol 350 mg I/ml. CT scans of the kidneys were taken before, immediately after, 8 h after and 32 h after the injection of contrast medium. To assess the rate of iopentol disappearance, calculations were made for the cortex, medulla and aorta, based on changes from the baseline (pre-contrast) measurements, in Hounsfield units (HU). The median estimated time for disappearance was 28 h from the cortex, 32 h from the medulla and 8 h from the aorta. Thus, a small retention of contrast medium can usually be seen after normalization of aortic HU values.