Influence of Ultra-Low-Dose and Iterative Reconstructions on the Visualization of Orbital Soft Tissues on Maxillofacial CT.

BACKGROUND AND PURPOSE: Dose reduction on CT scans for surgical planning and postoperative evaluation of midface and orbital fractures is an important concern. The purpose of this study was to evaluate the variability of various low-dose and iterative reconstruction techniques on the visualization of orbital soft tissues. MATERIALS AND METHODS: Contrast-to-noise ratios of the optic nerve and inferior rectus muscle and subjective scores of a human cadaver were calculated from CT with a reference dose protocol (CT dose index volume = 36.69 mGy) and a subsequent series of low-dose protocols (LDPs I-4: CT dose index volume = 4.18, 2.64, 0.99, and 0.53 mGy) with filtered back-projection (FBP) and adaptive statistical iterative reconstruction (ASIR)-50, ASIR-100, and model-based iterative reconstruction. The Dunn Multiple Comparison Test was used to compare each combination of protocols (α = .05). RESULTS: Compared with the reference dose protocol with FBP, the following statistically significant differences in contrast-to-noise ratios were shown (all, P ≤ .012) for the following: 1) optic nerve: LDP-I with FBP; LDP-II with FBP and ASIR-50; LDP-III with FBP, ASIR-50, and ASIR-100; and LDP-IV with FBP, ASIR-50, and ASIR-100; and 2) inferior rectus muscle: LDP-II with FBP, LDP-III with FBP and ASIR-50, and LDP-IV with FBP, ASIR-50, and ASIR-100. Model-based iterative reconstruction showed the best contrast-to-noise ratio in all images and provided similar subjective scores for LDP-II. ASIR-50 had no remarkable effect, and ASIR-100, a small effect on subjective scores. CONCLUSIONS: Compared with a reference dose protocol with FBP, model-based iterative reconstruction may show similar diagnostic visibility of orbital soft tissues at a CT dose index volume of 2.64 mGy. Low-dose technology and iterative reconstruction technology may redefine current reference dose levels in maxillofacial CT.

A randomized trial of a brief intervention for obesity in college students.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: • Brief motivational interventions have been found to be efficacious for obesity in older adult populations. • Brief motivational interventions including delivery of personalized feedback have been found to be efficacious for reducing college student drinking. WHAT THIS STUDY ADDS: • First study to test the efficacy of a one-session, brief motivational intervention for obesity among college students. • One session brief motivational interventions may have an impact on the reduction of calorie-dense foods and beverages. • A brief, one-session motivational interview with personalized feedback may not be an intensive enough intervention for obesity treatment among college students. SUMMARY: Young adults are at an increased risk for weight gain as they begin college and this has implications for the onset of future health consequences. Brief motivational interventions (BMIs) have been found to be effective with college students for reducing risky health behaviours such as alcohol consumption, but have not been developed and tested with a primary goal of reducing obesity. BMIs have been developed and tested for the treatment of obesity and weight-related health behaviours (WRHB) in other populations, such as adults and adolescents, with promising results. The purpose of the following study was to develop and test the efficacy of a BMI for weight loss among overweight and obese college students. Seventy undergraduate students (85.7% female, 57.1% African-American) completed an assessment about WRHBs and then were randomized to either receive a single 60-min BMI plus a booster phone call or to assessment only. At 3 months post-intervention, effect sizes within the intervention group were twice as large as within the assessment-only group on reductions in high-calorie foods and beverages. However, there were no statistically significant differences between groups on body mass index or WRHBs. The one-session nature of the session might not have been enough to produce significant change in weight.