Oral contrast agents for CT: a taste test survey.

PURPOSE: Our goal was to evaluate the palatability of the currently available oral contrast agents for CT. METHOD: We surveyed 202 adults (92 women and 110 men) with a mean age of 59 years. Each participant sampled five or eight products. The participants ingested 1 oz. of each product and recorded an overall score, taking into account the factors of palatability that were important to them. Scores were marked on a visual analog rating scale with 0 representing "dislike a lot" and 10 representing "like a lot." RESULTS: The following mean palatability scores were obtained: Gastrografin mixed with Tropical Punch Kool-Aid 8.2; Scan C 5.7; Cheetah 4.7; Readi-Cat 4.4; E-Z-Cat 4.0; Tomo-Cat 3.6, Prep-Cat 3.5; Baro-Cat 3.2; Lipomul mixed with water 3.1. CONCLUSION: Statistical cluster analysis suggested the following groupings of the products (i.e., products with statistically similar scores grouped together): Cluster 1-Kool-Aid with Gastrografin; Cluster 2-Scan C, Cheetah, Readi-Cat: Cluster 3-E-Z-Cat, Tomo-Cat, Prep-Cat, Baro-Cat, Lipomul.

Enhancing ascites: an aid to CT diagnosis.

Enhancement of ascitic fluid on delayed contrast-enhanced CT has been described as a potential pitfall in diagnosis. We present a case in which the phenomenon was beneficial to diagnosis. Enhancement of ascites was useful in delineating the entire extent of a cystic pelvic mass. We also discuss probable molecular and histologic mechanisms responsible for this unique type of enhancement.

Anatomic CT demonstration of the peritoneal spaces, ligaments, and mesenteries: normal and pathologic processes.

Computed tomography (CT) has become increasingly useful in the detection of intraabdominal disease. Owing to the widespread use of CT, it is essential that radiologists have a thorough understanding of the peritoneal spaces and the ligaments and mesenteries that form their boundaries. The majority of ligaments and mesenteries in the abdomen are formed from remnants of the ventral and dorsal mesenteries, which suspend the primitive gut. Unlike the abdominal ligaments, the pelvic ligaments are mainly formed by reflections of peritoneum over the pelvic organs or structures. The mesenteries and ligaments form the boundaries of the peritoneal spaces; this knowledge aids in localizing fluid collections, allowing the differential diagnosis to be narrowed. The ability to localize fluid collections accurately is also important if percutaneous or surgical drainage is to be performed. In addition, neoplasms can be more accurately staged when the pathway of spread through adjacent ligaments and mesenteries is understood.

High-speed photodiffractive effect in semi-insulating CdZnTe/ZnTe multiple quantum wells.

Single-pulse and cw measurements of the response of a semi-insulating CdZnTe/ZnTe multiple-quantum-well photorefractive device are presented. In single-pulse experiments, photodiffractive (absorption) gratings have been written with less than 1.8-microJ/cm(2) incident fluence, and a diffraction efficiency of 1.1% is obtained from the 1.56-microm active layer of the device. With an optimized structure, the ultimate response time of the device can be below 100 ps. In cw measurements a maximum diffraction efficiency of 1.35% is obtained.

Femtosecond KCl:Li and RbCl:Li color-center lasers near 2.8 microm with a HgCdTe multiple-quantum-well saturable absorber.

We have used HgCdTe multiple-quantum-well saturable absorbers to passively mode lock KCl:Li and RbCl:Li color-center lasers and have generated pedestal-free pulses as short as 120 fsec near 2.8 microm. To our knowledge, these are the shortest pulses in this wavelength range, and our laser is the only direct source of subpicosecond pulses in the mid-infrared region. Our results generalize the semiconductor passive mode-locking technique to different wavelength ranges, saturable absorber materials, and laser systems and are consistent with a model in which LO phonon collisions determine the fast saturable absorber behavior.