Neuroimaging Offers Low Yield in Children Positive for SARS-CoV-2.

The coronavirus disease 2019 (COVID-19) pandemic caused by Severe Acute Respiratory Syndrome coronavirus disease 2 (SARS CoV-2) most commonly presents with respiratory disease, but neurologic complications are being reported. We aimed to investigate the rate of positive neuroimaging findings in children positive for SARS-CoV-2 referred for neuroimaging between March 18 and September 30, 2020. We found that 10% (n = 2) had acute findings. Our results may suggest that in children, neurologic involvement in COVID-19 is rare, neuroimaging has a low yield in diagnosis, and acute neuroimaging should involve careful risk-benefit analysis.

Design of 3D-Printed Nasopharyngeal Swabs for Children is Enabled by Radiologic Imaging.

3D-printed nasopharyngeal swabs for COVID-19 molecular diagnostic testing address the national shortage of swabs. Swab designs for adult use were placed in the public domain in March 2020. Swabs for pediatric use, however, need to be smaller and more flexible to navigate delicate pediatric nasopharyngeal cavities. We describe a novel use of maxillofacial CT scans to aid in the design of pediatric nasopharyngeal swabs.

Multimodal Magnetic Resonance and Near-Infrared-Fluorescent Imaging of Intraperitoneal Ovarian Cancer Using a Dual-Mode-Dual-Gadolinium Liposomal Contrast Agent.

The degree of tumor removal at surgery is a major factor in predicting outcome for ovarian cancer. A single multimodality agent that can be used with magnetic resonance (MR) for staging and pre-surgical planning, and with optical imaging to aid surgical removal of tumors, would present a new paradigm for ovarian cancer. We assessed whether a dual-mode, dual-Gadolinium (DM-Dual-Gd-ICG) contrast agent can be used to visualize ovarian tumors in the peritoneal cavity by multimodal MR and near infra-red imaging (NIR). Intraperitoneal ovarian tumors (Hey-A8 or OVCAR3) in mice enhanced on MR two days after intravenous DM-Dual Gd-ICG injection compared to controls (SNR, CNR, p < 0.05, n = 6). As seen on open abdomen and excised tumors views and confirmed by optical radiant efficiency measurement, Hey-A8 or OVCAR3 tumors from animals injected with DM-Dual Gd-ICG had increased fluorescence (p < 0.05, n = 6). This suggests clinical potential to localize ovarian tumors by MR for staging and surgical planning, and, by NIR at surgery for resection.

High-resolution vascular imaging of the rat spine using liposomal blood pool MR agent.

BACKGROUND AND PURPOSE: High-resolution, vascular MR imaging of the spine region in small animals poses several challenges. The small anatomic features, extravascular diffusion, and low signal-to-noise ratio limit the use of conventional contrast agents. We hypothesize that a long-circulating, intravascular liposomal-encapsulated MR contrast agent (liposomal-Gd) would facilitate visualization of small anatomic features of the perispinal vasculature not visible with conventional contrast agent (gadolinium-diethylene-triaminepentaacetic acid [Gd-DTPA]). METHODS: In this study, high-resolution MR angiography of the spine region was performed in a rat model using a liposomal-Gd, which is known to remain within the blood pool for an extended period. The imaging characteristics of this agent were compared with those of a conventional contrast agent, Gd-DTPA. RESULTS: The liposomal-Gd enabled acquisition of high quality angiograms with high signal-to-noise ratio. Several important vascular features, such as radicular arteries, posterior spinal vein, and epidural venous plexus were visualized in the angiograms obtained with the liposomal agent. The MR angiograms obtained with conventional Gd-DTPA did not demonstrate these vessels clearly because of marked extravascular soft-tissue enhancement that obscured the vasculature. CONCLUSIONS: This study demonstrates the potential benefit of long-circulating liposomal-Gd as a MR contrast agent for high-resolution vascular imaging applications.

Determination of anti-HBsAg IgM monoclonal antibodies in cell culture media by perfusion immunoassay.

A rapid, specific, perfusion immunoassay for active anti-HBsAg monoclonal IgM is described. The immunoassay requires less than 3.5 min per sample. The precision was found to be 3.6% at an IgM concentration of 17 microg/ml. A detection limit of 1 microg/ml IgM in culture media was determined. Assay results were found to correlate very well with standard size exclusion chromatography and radial immunodiffusion techniques. This perfusion immunoassay was demonstrated to be useful for determining anti-HBsAg IgM in complex matrices such as cell culture media. The utility of the immunoassay for monitoring production of anti-HBsAg IgM in a perfusion bioreactor is demonstrated.

XPS and TOF-SIMS microanalysis of a peptide/polymer drug delivery device.

The localization of a peptide drug dispersed in a solid matrix of hydroxypropyl cellulose (HPC) was determined at micrometer lateral resolution using secondary ion mass spectrometry (SIMS)/ion microscopy. Leuprolide formulated as a sustained release drug delivery device has been selected as a model compound for this investigation. One key facet of this study was to attempt to understand the distribution and ultimate bioavailability of the peptide dispersed in an inert polymer matrix. The results reported in this paper demonstrate that the lateral distribution of leuprolide along the surfaces of cross sections prepared from different polymer formulations is different. Ion microscopy directly measures the lateral distribution of protonated molecular ions as well as specific fragment peaks and provides a direct method of determining peptide distributions in polymers. Ion images of leuprolide dispersed in HPC demonstrate that the peptide distribution is critically dependent on polymer composition. The mass spectrometry results augment quantitative X-ray photoelectron (XPS) measurement of C and N levels in different polymer/peptide formulations. The combination of XPS and TOF-SIMS techniques provides a powerful method for determining the distribution of peptides in polymer matrices.