Increasing the detection rate of congenital heart disease during routine obstetric screening using cine loop sweeps.

OBJECTIVES: The purpose of this study was to demonstrate an increase in the detection rate of fetal cardiac defects using 2 cine loop sweeps. METHODS: Image reviewers examined a series of 93 cases randomly sorted, including 79 studies with normal findings and 14 studies with abnormal findings. All of the images were assessed by 5 standard criteria. Cases were classified as normal, abnormal, or indeterminate. Reviewers using the conventional approach reviewed 3 still images: the 4-chamber, left ventricular outflow tract, and right ventricular outflow tract views. Reviewers using the cine loop sweeps viewed 2 grayscale sweeps through the fetal heart in real time. The image sequences were reviewed independently by 2 experts, 3 nonexperts, and 2 sonographers blinded to each others' results. RESULTS: The cine loop sweeps had an increased detection rate of 38% for the nonexperts and 36% for the experts compared with the conventional approach. The cine loop sweeps allowed identification of all cardiac defects by at least 2 of the 7 reviewers; the percentage of cases with false-positive findings was 3.9%. With the conventional approach, 2 defects went undetected by all reviewers, and 4 defects were found by only 1 reviewer; the percentage of cases with false-positive findings was 5.4%. CONCLUSIONS: The use of cine loop sweeps has the potential to increase the detection of fetal cardiac defects without increasing the rate of false-positive findings or increasing the interpretation and decision-making times.

Optimizing the Exposure Indicator as a Dose Management Strategy in Computed Radiography.

PURPOSE: To investigate a technique for optimizing radiation dose and image quality for a computed radiography system. METHODS: Entrance skin doses were measured for phantom models of the pelvis and lumbar spine imaged using the vendor's recommended exposure settings (ie, the reference doses) as well as doses above and below the vendor's recommended settings for both body parts. Images were assessed using visual grading analysis (VGA). RESULTS: The phantom dosimetry results revealed strong positive linear relationships between dose and milliampere seconds (mAs), mAs and inverse exposure indicator (EI), and dose and inverse EI for both body parts. The VGA showed that optimized values of 16 mAs/EI = 136 for the anteroposterior (AP) pelvis and 32 mAs/EI = 139 for the AP lumbar spine did not compromise image quality. DISCUSSION: Selecting optimized mAs reduced dose by 36% compared with the vendor's recommended mAs (dose) values. CONCLUSION: Optimizing the mAs and associated EIs can be an effective dose management strategy.

The effect of applied transducer force on acoustic radiation force impulse quantification within the left lobe of the liver.

Introduction: Acoustic Radiation Force Impulse (ARFI) Quantification measures shear wave velocities (SWVs) within the liver. It is a reliable method for predicting the severity of liver fibrosis and has the potential to assess fibrosis in any part of the liver, but previous research has found ARFI quantification in the right lobe more accurate than in the left lobe. A lack of standardised applied transducer force when performing ARFI quantification in the left lobe of the liver may account for some of this inaccuracy. The research hypothesis of this present study predicted that an increase in applied transducer force would result in an increase in SWVs measured. Methods: ARFI quantification within the left lobe of the liver was performed within a group of healthy volunteers (n = 28). During each examination, each participant was subjected to ARFI quantification at six different levels of transducer force applied to the epigastric abdominal wall. Results: A repeated measures ANOVA test showed that ARFI quantification was significantly affected by applied transducer force (p = 0.002). Significant pairwise comparisons using Bonferroni correction for multiple comparisons showed that with an increase in applied transducer force, there was a decrease in SWVs. Conclusion: Applied transducer force has a significant effect on SWVs within the left lobe of the liver and it may explain some of the less accurate and less reliable results in previous studies where transducer force was not taken into consideration. Future studies in the left lobe of the liver should take this into account and control for applied transducer force.

Impact of audio/visual systems on pediatric sedation in magnetic resonance imaging.

PURPOSE: To evaluate the use of an audio/visual (A/V) system in pediatric patients as an alternative to sedation in magnetic resonance imaging (MRI) in terms of wait times, image quality, and patient experience. MATERIALS AND METHODS: Pediatric MRI examinations from April 8 to August 11, 2008 were compared to those 1 year prior to the installation of the A/V system. Data collected included age, requisition receive date, scan date, and whether sedation was used. A posttest questionnaire was used to evaluate patient experience. Image quality was assessed by two radiologists. RESULTS: Over the 4 months in 2008 there was an increase of 7.2% (115; P < 0.05) of pediatric patients scanned and a decrease of 15.4%, (67; P = 0.32) requiring sedation. The average sedation wait time decreased by 33% (5.8 months) (P < 0.05). Overall, the most positively affected group was the 4-10 years. The questionnaire resulted in 84% of participants expressing a positive reaction to the A/V system. Radiological evaluation revealed no changes in image quality between A/V users and sedates. CONCLUSION: The A/V system was a successful method to reduce patient motion and obtain a quality diagnostic MRI without the use of sedation in pediatric patients. It provided a safer option, a positive experience, and decreased wait times.