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Background: Although CT urography (CTU) is widely used for the evaluation of the entire urinary tract, the most important drawback is the radiation exposure., Purpose: To evaluate the effect of a noise reduction filter (NRF) using a phantom and to quantitatively and qualitatively compare excretory phase (EP) images using a low noise index (NI) with those using a high NI and postprocessing NRF (pNRF)., Material and Methods: Each NI value was defined for a slice thickness of 5 mm, and reconstructed images with a slice thickness of 1.25 mm were assessed. Sixty patients who were at high risk of developing bladder tumors (BT) were divided into two groups according to whether their EP images were obtained using an NI of 9.88 (29 patients; group A) or an NI of 20 and pNRF (31 patients; group B). The CT dose index volume (CTDI(vol)) and the contrast-to-noise ratio (CNR) of the bladder with respect to the anterior pelvic fat were compared in both groups. Qualitative assessment of the urinary bladder for image noise, sharpness, streak artifacts, homogeneity, and the conspicuity of polypoid or sessile-shaped BTs with a short-axis diameter greater than 10 mm was performed using a 3-point scale., Results: The phantom study showed noise reduction of approximately 40% and 76% dose reduction between group A and group B. CTDI(vol) demonstrated a 73% reduction in group B (4.6 ± 1.1 mGy) compared with group A (16.9 ± 3.4 mGy). The CNR value was not significantly different (P = 0.60) between group A (16.1 ± 5.1) and group B (16.6 ± 7.6). Although group A was superior (P < 0.01) to group B with regard to image noise, other qualitative analyses did not show significant differences., Conclusion: EP images using a high NI and pNRF were quantitatively and qualitatively comparable to those using a low NI, except with regard to image noise.

An interventional-radiology computed-tomography (IVR-CT)/angio system is a combination of an angiographic unit and a CT scanner. This system allows patient's movement in and out of the two imaging units, on the same table. Since June 2003, we have applied our conventional protocol for evaluation of cerebral blood perfusion during interventional radiology (IVR) procedures. We reviewed our experience using the IVR-CT/angio system and investigated the efficacy and limitations of this technique. No complications relating to radiation exposure, contrast medium use, or IVR procedures were observed. CT perfusion was useful for detecting cerebral perfusion impairment during IVR procedures. This was helpful in deciding the postoperative management. Because patients do not need to be transported to another radiographic suite to evaluate cerebral blood perfusion, the IVR-CT/angio system is ideal for safely and simply detecting cerebral perfusion defects during IVR procedures. However, it is important to consider whether there is sufficient indication for the procedure, because radiation exposure and the amount of contrast medium use are increased if the IVR procedures become difficult.

Carboxylate and ammonium functionalities-32 of each-facilitate electrostatic interaction between oppositely charged dendrimer electrolytes and porphyrin cores, which leads in protic media to a supramolecular, fluorescence-active aggregate of two chromophores that communicate and have a predictable topology (see drawing on the right; A=acceptor, D=donor). In contrast to the complexation of linear polyelectrolytes, the contact area for the two dendrimer molecules is very limited, just as one would expect for an assembly of spherical molecules., (© 1998 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.)