Comparison of gadolinium chelates with manganese-DPDP for liver lesion detection and characterization: Preliminary results

Nonspecific extracellular gadolinium chelate (NEGd) was prospectively compared with manganese (Mn)-DPDP (Mn) for the detection and characterization of focal liver lesions of various histology. Seventeen patients with known or suspected focal liver lesions underwent NEGd and Mn-enhanced studies at 1.5 T. Study findings were correlated with histology (five patients), computed tomography (CT) examinations (17 patients), and 4- to 13-month imaging follow-up by CT and/or MR (five patients). NEGd studies were performed as serial postcontrast spoiled gradient echo (SGE) sequences, and Mn studies were performed as SGE sequences 15 and 30 min postcontrast and T₁-weighted, fat-suppressed spin echo at 16 min. NEGd and Mn images were prospectively interpreted in a separate blinded fashion. Lesion detection and characterization were determined. NEGd and Mn-enhanced images demonstrated 61 and 49 lesions, respectively (p = .1, NS). A total of 60 and 33 lesions were characterized on NEGd and Mn images, respectively, which was significantly different (p = .008). No differences were observed for the detection and characterization of liver metastases; whereas there was a trend for superior detection and characterization for hepatocellular carcinoma with NEGA.     

Uniform polyolefin and polymethacrylate

Preparations and properties of synthetic uniform polyolefins and polymethacrylates are described with emphasizing the necessity of their utilization for understanding the fundamental problems in polymer chemistry. Uniform polymer is a polymer composed of molecules uniform with respect to molecular weight and constitution. While classical organic chemistry provides means of constructing uniform polymers such as poly(methylene)s in stepwise manners, recent advances in separation technology such as supercritical fluid chromatography (SFC) have made it possible to isolate synthetic uniform polymers from its homologous mixture. Combinations of stereospecific polymerizations and the SFC technique have enabled us to prepare uniform polystyrenes and poly(methyl methacrylate)s with high stereoregularities, which are very useful for systematic studies on the nature of polymers. The thermal properties of these uniform polymers are discussed in some detail.     

ChemInform Abstract: Preparation and Crystal Structure of Rare Earth Rhenates: The Series Ln5Re2O12 with Ln: Y,Gd—Lu,and the Praseodymium Rhenates Pr3ReO8, Pr3Re2O10, and Pr4Re2O11.

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