Has pediatric CT at children's hospitals reached its peak?

OBJECTIVE: CT volumes at our institution have declined since 2005. The purpose of this article is to discuss the existence of any corresponding national trend. CONCLUSION: CT utilization as a percentage of cross-sectional imaging studies has decreased steadily since 2003 in pediatric facilities across North America.

Accuracy of cross-table lateral knee radiography for evaluation of joint effusions.

OBJECTIVE: The purpose of our study was to investigate the efficacy of cross-table lateral knee radiography in the diagnosis of knee effusions compared with an MRI reference standard, to evaluate reader experience in effusion assessment, and to establish a new threshold for suprapatellar pouch measurement for the diagnosis of effusion. MATERIALS AND METHODS: First- and third-year radiology residents and an attending musculoskeletal radiologist retrospectively assessed 108 cross-table lateral knee radiographs for qualitative grading of joint fluid and quantitative measurement of the suprapatellar pouch. Qualitative and quantitative evaluation of ipsilateral knee MRI examinations performed within 1 week of radiography was performed by two attending musculoskeletal radiologists as a reference standard. RESULTS: Qualitative visual grading of cross-table lateral radiographs had a sensitivity of 90-92%, specificity of 39-54%, and accuracy of 69-76% for joint effusion. Extrapolating from previous work showing 4 mL of fluid distends the suprapatellar pouch to 4 mm on midline sagittal MRI, the corresponding measurement on cross-table lateral radiographs was predicted to be 7 mm. Using this new criterion of effusion, sensitivity, specificity, and accuracy compared with an MR midline sagittal reference standard were 76%, 83%, and 81%, respectively. Historical data for overhead lateral radiographs had a sensitivity of 78%, specificity of 80%, and accuracy of 79%. CONCLUSION: Qualitative visual assessment of cross-table lateral knee radiographs is highly sensitive for the detection of joint effusion. By performing quantitative evaluation with a new 7-mm criterion for suprapatellar pouch measurement, sensitivity, specificity, and accuracy are equivalent to that of overhead lateral radiography.

Current use of computed tomographic urography: survey of the society of uroradiology.

OBJECTIVE: To determine uroradiologists' opinions and practices regarding computed tomographic (CT) urography. METHODS: A Web-based survey was sent via e-mail to all 259 members of the Society of Uroradiology. Of the 229 successfully delivered e-mails, 90 (39%) members responded. RESULTS: Of 90 uroradiologists, 87% perform CT urography. Compared with intravenous (IV) urography, 69% of uroradiologists use CT urography more than 75% of the time urinary tract imaging is requested; 27% stated that CT urography has completely replaced IV urography. Most uroradiologists perform CT urography using multidetector-row CT alone (79%) and use a 3-phase technique (52%) using a single injection (76%) of contrast material at 3 mL/s (52%) without a compression device (81%) and with the patient in supine position (80%). CONCLUSIONS: Most uroradiologists use CT urography in their practice today; some no longer perform IV urography. Variability in multidetector-row CT technique suggests that more research is needed to determine the optimal protocol.

Increasing memory load modulates regional brain activity in older adults as measured by fMRI.

Several recent studies using functional magnetic resonance imaging (fMRI) during recognition memory tests have suggested that the ability to neuromodulate as a function of cognitive demand may be impaired in older adults due to age-related cell loss and neural volume reduction in memory specific regions. In the current study, older adults (ages 59-77) were tested with fMRI during a delayed-recognition task in which memory load for faces was varied across trials. Activity was greater in amplitude for three- versus one-face stimuli within the superior, middle, and inferior frontal gyri, intraparietal sulcus, and fusiform gyrus. It was concluded that the ability to modulate activity with increasing load is preserved in older adults despite reductions in neural volume.