Magnetic Resonance Imaging Microscopy Research Articles

Lymph nodes: microstructural anatomy at MR imaging.

High-resolution microscopic magnetic resonance (MR) images of rodent lymph nodes were directly correlated with sections obtained for histologic study to determine the microstructural anatomy of lymph nodes seen at MR imaging and to evaluate signal intensity changes induced by a novel intravenous lymphotropic MR contrast agent (ultrasmall superparamagnetic iron oxide [USPIO]). High-resolution T2-weighted images of unenhanced lymph nodes demonstrated medullary sinus as regions of low signal intensity and follicles as high-intensity structures. After a single intravenous administration of USPIO (160 mumol/kg), both T1-weighted and T2-weighted images showed areas of focal signal intensity loss in medullary sinuses corresponding to the distribution of uptake by macrophages. Lymph follicles appeared unchanged in signal intensity, as they are largely devoid of macrophages. This model of microscopic MR imaging should provide the basis for (a) understanding differences between patterns of contrast-enhanced normal lymph nodes and those of diseased ones and (b) guiding the development of targeting strategies for novel pharmaceuticals at the cellular level.

Magnetic Resonance Microscopy of Stem Tissues of Pelargonium hortorum

Nuclear magnetic resonance microscopy imaging shows great promise for nondestructive in vivo plant anatomy studies at microscopic levels. Magnetic resonance imaging was used to acquire nondestructively images of stem tissue in Pelargonium hortorum x Bailey with 47 x 47 μm resolution and a slice 600 μm thick. Images were acquired with a 2 T superconducting magnet utilizing a flat strip solenoidal resonator and a three-dimension spin warp (3DFT) imaging sequence. Living plant tissue structures corresponding to those seen with conventional light microscopic techniques were visualized with sufficient in-plane resolution to discern individual cells.