Added utility of gadolinium in the magnetic resonance imaging (MRI) workup of seizures in children younger than 2 years.

The purpose of this study was to evaluate the added utility of gadolinium administration in the magnetic resonance imaging (MRI) workup of seizures in children younger than 2 years. A computerized retrospective search of the radiology information system identified all brain MRI examinations performed at the authors' institution from 1995 to 2002 for children younger than 2 years. Review of the clinical records revealed that 437 of a total 1466 brain magnetic resonance examinations performed on this subset of the pediatric population were performed as part of an initial seizure workup. Magnetic resonance reports and clinical notes were reviewed. MRI studies with enhancing lesions as well as those with equivocal findings were also reviewed in a consensus fashion by 2 senior neuro-radiologists and 2 radiology residents. Contrast administration was rated as essential, helpful, or not helpful for each study. Administration of contrast medium was felt to be essential in formulating a diagnosis in a total of 8 (1.8%) studies, all of which involved documented or highly suspected cases of infection. In an additional 26 cases (5.9%), which included 4 cases of neoplasm, contrast was felt to be useful but not essential in reaching a diagnosis. Contrast was judged not helpful in making the diagnosis in the other 403 studies (92.3%).

In vivo droplet vaporization for occlusion therapy and phase aberration correction.

The objective was to determine whether a transpulmonary droplet emulsion (90%, <6 microm diameter) could be used to form large gas bubbles (>30 microm) temporarily in vivo. Such bubbles could occlude a targeted capillary bed when used in a large number density. Alternatively, for a very sparse population of droplets, the resulting gas bubbles could serve as point beacons for phase aberration corrections in ultrasonic imaging. Gas bubbles can be made in vivo by acoustic droplet vaporization (ADV) of injected, superheated, dodecafluoropentane droplets. Droplets vaporize in an acoustic field whose peak rarefactional pressure exceeds a well-defined threshold. In this new work, it has been found that intraarterial and intravenous injections can be used to introduce the emulsion into the blood stream for subsequent ADV (B- and M-mode on a clinical scanner) in situ. Intravenous administration results in a lower gas bubble yield, possibly because of filtering in the lung, dilution in the blood volume, or other circulatory effects. Results show that for occlusion purposes, a reduction in regional blood flow of 34% can be achieved. Individual point beacons with a +24 dB backscatter amplitude relative to white matter were created by intravenous injection and ADV.