PubMed · 6074273
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K Stapor. 1967. Calycorenal backflow.. https://doi.org/10.1111/j.1464-410x.1967.tb09859.x
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OBJECTIVES: This systematic review and meta-analysis are aimed at evaluating the incidence of adverse drug reactions (ADRs) following administration of clinically approved ultrasound contrast agents (UCAs) in adults and children, to assess risks in patients with cardiovascular disease and in pregnancy, and to evaluate the effectiveness of emergency management of severe ADRs. MATERIALS AND METHODS: A PRISMA 2020 systematic review was conducted searching PubMed, Scopus, and Embase. Two reviewers independently screened, extracted data, and assessed quality. Incidence estimates were pooled when feasible, stratified by age group, contrast agent, and administration route. RESULTS: Seventy-four studies encompassing > 1 million adults and > 36,000 children were included, contributing multiple analytic cohorts to the quantitative synthesis. Severe acute ADRs were extremely rare (6 and 16 cases per 100,000 in adults and children, respectively) and absent following endocavitary administration in children. Non-severe acute ADRs occurred in 11 and 8 cases per 10,000 adults and children, respectively. Delayed reactions were very rare (< 1 case per million in adults). No significant safety differences emerged between UCA products. The incidence of ADRs in patients with cardiovascular disease was analogous to the general population. No ADRs were reported in pregnant women. Standard emergency management was effective in almost all serious cases, though rare fatalities occurred. CONCLUSION: UCAs show an excellent safety profile in adults and children, with very rare severe ADRs and few non-severe, typically self-limiting reactions. Strict adherence to recommended emergency management protocols mitigates the remaining risks, supporting safe use across a broad range of clinical indications. PROSPERO REGISTRATION: CRD42023432668. KEY POINTS: Question What is the incidence, type, and severity of acute and delayed ADRs associated with clinically approved UCAs across different patient populations? Findings Severe acute adverse reactions are very rare, and non-severe reactions are rare and self-limiting, with no significant safety differences between adults, children, or patients with cardiovascular disease. Clinical relevant UCAs show an excellent safety profile across populations. These findings support their safe clinical use as reliable alternatives to iodine-based and gadolinium-based contrast agents in routine diagnostic imaging.
The conformational behavior of four [Ln(DOTA)(H(2)O)](-) systems (Ln = La, Gd, Ho, and Lu) has been characterized by means of ab initio calculations performed in vacuo and in aqueous solution, the latter by using the polarizable continuum model (PCM). Calculated molecular geometries and conformational energies of the [Ln(DOTA)(H(2)O)](-) systems, and interconversion mechanisms, barriers, and (13)C NMR spectra of the [Lu(DOTA)](-) complex are compared with experimental values. For each system, geometry optimizations, performed in vacuo and in solution at the HF/3-21G level and using a 46+4f(n) core electron effective core potential (ECP) for lanthanides, provide two minima corresponding to a square antiprismatic (A) and an inverted antiprismatic (IA) coordination geometry. All the systems are nonacoordinated, with the exception of the IA isomer of the Lu complex that, from in solution calculations, is octacoordinated, in agreement with experimental data. On comparing the in vacuo relative free energies calculated at different theory levels it can be seen that the nonacoordinated species dominates at the beginning of the lanthanide series while the octacoordinated one does so at the end. Furthermore, on passing along the series the IA isomer becomes less and less favored with respect to A and for the Lu complex a stabilization of the IAisomer is observed in solution (but not in vacuo), in agreement with the experimental data. Investigation of the A<-->IA isomerization process in the [Lu(DOTA)](-) system provides two different interconversion mechanisms: a single-step process, involving the simultaneous rotation of the acetate arms, and a multistep path, involving the inversion of the cyclen cycle configuration. While in vacuo the energy barrier for the acetate arm rotation is higher than that involved in the ring inversion (23.1 and 13.1 kcal mol(-)(1) at the B3LYP/6-311G level, respectively), in solution the two mechanisms present comparable barriers (14.7 and 13.5 kcal mol(-)(1)), in fairly good agreement with the experimental values. The NMR shielding constants for the two isomers of the [Lu(DOTA)](-) complex have been calculated by means of the ab initio GIAO and CSGT methods, and using a 46-core-electron ECP for Lu. The calculated (13)C NMR chemical shifts are in close agreement with the experimental values (rms 3.3 ppm, at the HF/6-311G level) and confirm the structural assignment of the two isomers based on experimental NMR spectra in solution. The results demonstrate that our computational approach is able to predict several physicochemical properties of lanthanide complexes, allowing a better characterization of this class of compounds for their application as contrast agents in medical magnetic resonance imaging (MRI).
Peripheral subtraction scanning is used to trace the blood vessels of upper and lower extremities. In some modern C-arm fluoroscopy systems this function is performed automatically. In this mode the system is programmed to advance and stop in a series of steps taking a mask image at each point. The system then repeats each step after the contrast agent has been injected, and produces a DSA image at each point. Current radiographic quality assurance protocols do not address this feature. This note reviews methods of measuring system vibration while images are being acquired in automated peripheral stepping. The effect on image quality pre- and post-image processing is assessed. Results show that peripheral stepping DSA does not provide the same degree of image quality as static DSA. In examining static test objects, the major cause of the reduction in image quality is misregistration due to vibration of the image intensifier during imaging.