Developing agents high-contrast

Uses Developing agent for film or paper gives warm black images with caustic soda, gives rapid development with high contrast. 

For monomer Gd(III) complexes the inner and outer sphere mechanisms contribute more or less to the same extent to the overall paramagnetic relaxation enhancement. The development of high relaxivity contrast agents mainly involves increasing the inner sphere term, since the outer sphere contribution can hardly be modified. For the new generation macromolecular agents, therefore, the inner sphere relaxivity becomes much more significant (over 90% of total relaxivity). 

To overcome these drawbacks, developing agents of high activity and short induction periods are required. Phenidone and hydroquinone are suitable monobath developing agents. A combination of these two generally leads to higher speed, improved contrast, and maximum density. 

Fig. 3.6a-C. MDCT in portal venous phase (a) and MRI with a Tl-w 3D gradient-echo sequence after gadolinium-injection (b) and a T2 -w gradient-echo sequence after injection of the SPIO contrast agent ferucarbotran (c) in a male patient suffering from a colorectal carcinoma in whom atypical resection of a liver metastasis in the right lobe of the liver had been performed previously. Note the postoperative bilioma (marked by the asterisk). In the MDCT examination no further liver lesions can be detected, whereas the gadolinium-enhanced MRI faintly shows a hypervascular lesion arrow). The SPlO-enhanced MRI scan clearly depicts a newly developed metastasis with a high contrast between lesion and adjacent liver parenchyma...

Low Osmolality Contrast Media. An ideal intravascular CM possesses several properties high opacity to x-rays, high water solubihty, chemical stabihty, low viscosity, low osmolahty, and high biological safety. Low cost and patentabihty are also important for commercial agents. The newer nonionic and low osmolar agents represent an advanced class of compounds in the development of x-ray contrast media. 

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