Imaging of Bone Marrow.

Bone marrow is the essential for function of hematopoiesis, which is vital for the normal functioning of the body. Bone marrow disorders or dysfunctions may be evaluated by blood workup, peripheral smears, marrow biopsy, plain radiographs, computed tomography (CT), MRI and nuclear medicine scan. It is important to distinguish normal spinal marrow from pathology to avoid missing a pathology or misinterpreting normal changes, either of which may result in further testing and increased health care costs. This article focuses on the diffuse bone marrow pathologies, because the majority of the bone marrow pathologies related to hematologic disorders are diffuse.

In vitro assessment of EmboGel and UltraGel radiopaque hydrogels for the endovascular treatment of aneurysms.

PURPOSE: To describe two hydrogel embolic materials, the alginate-based EmboGel and the polyethylene glycol diacrylate-based UltraGel and examine their use as embolic agents in in vitro models of abdominal aortic aneurysm (AAA) endoleak and saccular aneurysms. MATERIALS AND METHODS: EmboGel is a mixture of iohexol and alginate, with a calcium chloride solution used to induce polymerization. UltraGel is a mixture of igracure, iohexol, and polyethylene glycol diacrylate and polymerizes in the presence of ultraviolet (UV) light. Modified microcatheter delivery systems were used in both cases to demonstrate use of the hydrogels in fusiform and saccular aneurysm models. RESULTS: Preliminary in vitro results suggest that EmboGel and UltraGel provide effective embolization in fusiform and saccular aneurysm models, respectively. Due to the rapid polymerization of EmboGel, the agent was delivered in a strand-like form. When used in conjunction with a stent in an AAA endoleak model, this form was able to effectively fill the aneurysmal cavity and occlude it from the central blood flow. UltraGel, conversely, was delivered as a liquid and slowly polymerized in the presence of UV light. This system in a saccular aneurysm model was able to form a solid cast inside the aneurysm wall, again showing complete occlusion from the parent flow. CONCLUSIONS: Preliminary results indicate these two novel hydrogel applications may prove effective for the treatment of saccular and fusiform aneurysms.

Magnetoelectroporation: improved labeling of neural stem cells and leukocytes for cellular magnetic resonance imaging using a single FDA-approved agent.

Cellular magnetic resonance imaging (MRI) relies on the use of intracellular contrast agents, primarily iron oxide compounds. Several techniques have been used to efficiently shuttle iron oxides into nonphagocytic cells, but all methods used until now require a prolonged incubation of cells. We hypothesized that instant magnetic labeling of cells could be achieved using electroporation. Neural stem cells (NSCs) and leukocytes from spleen and lymph nodes were suspended in a ferumoxide labeling solution, loaded into cuvettes, and subjected to electromechanical permeabilization using electroporation. Magnetically labeled cells were assayed for labeling efficiency, as well as for potential toxicity or altered function. To confirm the method's applicability to detect cells, MRI experiments were performed at 11.7 T. Magnetoelectroporation of NSCs, as demonstrated by Prussian blue staining, anti-dextran immunostaining, and a quantitative iron uptake assay, proved to be an efficient intracellular magnetic labeling method. Leukocytes including lymphocytes, which are notoriously difficult to label because of their membrane properties and small cytoplasmic volume, also demonstrated a pronounced uptake of ferumoxide. MRI experiments showed that labeled NSCs could be visualized as single cells and cell clusters in gelatin phantoms, and as proliferating cell masses in mouse brain. We have developed a convenient technique for instant magnetic labeling of cells. Because magnetoelectroporation allows the use of ferumoxides approved by the US Food and Drug Administration without additional agents, it has excellent potential for clinical translation.