Assessment of quiet T2 weighted PROPELLER sequence in pediatric abdominal imaging.

INTRODUCTION: Elevated acoustic noise during Magnetic Resonance Imaging (MRI) has been associated with patient anxiety and altered cochlear function. Acoustic Reduction Technique (ART) T2 weighted (T2w) periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) has been studied in brain MR but not abdominopelvic imaging. The purpose of our study was to evaluate the image quality and acoustic noise level of ART T2w PROPELLER sequence in comparison with the conventional T2w PROPELLER sequence in pediatric abdomino-pelvic imaging. METHODS: Eleven consecutive pediatric patients undergoing abdomino-pelvic MRI were scanned on a 3 Tesla magnet using standard and ART T2w PROPELLER sequences. After scanning completion, objective sound level measurements were performed with a sound level meter and microphone. Mann-Whitney U test was used for a non-parametric two-tailed statistical analysis of acoustics, image rating and scan time with significance level set to 0.05. Overall inter-rater agreement was calculated using Cohen's kappa coefficient. RESULTS: Eleven pediatric patients (4 females and 7 males) between 26 days and 18 years of age (mean = 10.0, SD = 5.8) were included. ART T2w produced lower levels of acoustic noise than standard technique in a comparison of mean decibel readings from eleven trials of standard and ART T2w (p value = 0.00008). Streak artifacts were rated greater in ART T2w by both raters (p-value = 0.00278 and 0.00252). There was no significant difference in bile duct blurring, respiratory ghosting, pulsation, fat suppression or hepatic parenchymal depiction. CONCLUSION: Presence of additional streaking artifacts should be considered along with the benefit of reduced acoustic noise from ART T2w.

Radiologic assessment of fetal tracheal balloon occlusion.

Fetal endoscopic tracheal occlusion (FETO) is a novel technique to treat cases of isolated severe congenital diaphragmatic hernia (CDH). Although there are benefits of MRI over ultrasound in assessing lung volumes, it is unknown whether there are benefits of MRI for localizing the tracheal balloon. This is a retrospective study reviewing the imaging characteristics of FETO in patients who underwent both MRI and ultrasound exams done to localize tracheal balloons.

Pairwise comparison versus Likert scale for biomedical image assessment.

OBJECTIVE: Biomedical imaging research relies heavily on the subjective and semi-quantitative reader analysis of images. Current methods are limited by interreader variability and fixed upper and lower limits. The purpose of this study was to compare the performance of two assessment methods, pairwise comparison and Likert scale, for improved analysis of biomedical images. MATERIALS AND METHODS: A set of 10 images with varying degrees of image sharpness was created by digitally blurring a normal clinical chest radiograph. Readers assessed the degree of image sharpness using two different methods: pairwise comparison and a 10-point Likert scale. Reader agreement with actual chest radiograph sharpness was calculated for each method by use of the Lin concordance correlation coefficient (CCC). RESULTS: Reader accuracy was highest for pairwise comparison (CCC, 1.0) and ranked Likert (CCC, 0.99) scores and lowest for nonranked Likert scores (CCC, 0.83). Accuracy improved slightly when readers repeated their assessments (CCC, 0.87) or had reference images available (CCC, 0.91). CONCLUSION: Pairwise comparison and ranked Likert scores yield more accurate reader assessments than nonranked Likert scores.