Purpose:To determine the interobserver reproducibility of the Prostate Imaging Reporting and Data System (PI-RADS) version 2 lexicon. Materials and Methods:This retrospective HIPAA-compliant study was institutional review board-approved. Six radiologists from six separate institutions, all experienced in prostate magnetic resonance (MR) imaging, assessed prostate MR imaging examinations performed at a single center by using the PI-RADS lexicon. Readers were provided screen captures that denoted the location of one specific lesion per case. Analysis entailed two sessions (40 and 80 examinations per session) and an intersession training period for individualized feedback and group discussion. Percent agreement (fraction of pairwise reader combinations with concordant readings) was compared between sessions. k coefficients were computed. Results:No substantial difference in interobserver agreement was observed between sessions, and the sessions were subsequently pooled. Agreement for PI-RADS score of 4 or greater was 0.593 in peripheral zone (PZ) and 0.509 in transition zone (TZ). In PZ, reproducibility was moderate to substantial for features related to diffusion-weighted imaging (k = 0.535-0.619); fair to moderate for features related to dynamic contrast material-enhanced (DCE) imaging (k = 0.266-0.439); and fair for definite extraprostatic extension on T2-weighted images (k = 0.289). In TZ, reproducibility for features related to lesion texture and margins on T2-weighted images ranged from 0.136 (moderately hypointense) to 0.529 (encapsulation). Among 63 lesions that underwent targeted biopsy, classification as PI-RADS score of 4 or greater by a majority of readers yielded tumor with a Gleason score of 3+4 or greater in 45.9% (17 of 37), without missing any tumor with a Gleason score of 3+4 or greater. Conclusion:Experienced radiologists achieved moderate reproducibility for PI-RADS version 2, and neither required nor benefitted from a training session. Agreement tended to be better in PZ than TZ, although was weak for DCE in PZ. The findings may help guide future PI-RADS lexicon updates.q RSNA, 2016

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A 29% decrease in CTDI(vol) and a 20% decrease in DLP were obtained in scans with ASIR compared with scans without ASIR, without a quantitative loss of image quality.

Purpose: To compare two T1-weighted (T1W) fat-suppressed sequences for 3D breath-hold pre-and postcontrast fat-suppressed T1W imaging of the female pelvis at 3T. Materials and Methods:Pelvic MRI scans of 16 female patients were retrospectively identified who were scanned with two 3D breath-hold sequences: 1) a fast spoiled gradient echo sequence with spectral inversion at lipids (SPE-CIAL) (called 3D FSPGR), and 2) a dual-echo two-point Dixon (DE Dixon) sequence. Contrast between soft tissue and fat, soft tissue and fluid, and fat and fluid was measured on pre-and postcontrast images. Additionally, two readers subjectively scored the images for degree and homogeneity of fat suppression plus presence and severity of artifacts. Results:Contrast between muscle and myometrium to fat was improved with the Dixon technique (0.61 vs. 0.09 and 0.7 vs. 0.3, respectively, P Ͻ 0.001). Both readers agreed that fat suppression was stronger with the Dixon sequence (P Ͻ 0.001 and P ϭ 0.06). Artifacts were equivalent (P ϭ 0.53 and 0.65). Conclusion:The 3D DE Dixon sequence achieved stronger fat suppression in the female pelvis when compared to a 3D FSPGR sequence with SPECIAL.

BackgroundLeft atrial (LA) late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) imaging is indicative of fibrosis, and has been correlated with reduced LA function, increased LA volume, and poor procedural outcomes in cohorts with atrial fibrillation (AF). However, the role of LGE as a prognostic biomarker for arrhythmia in cardiac disease has not been examined.MethodsIn this study, we assessed LA LGE using a 3D LGE CMR sequence to examine its relationships with new onset atrial arrhythmia, and LA and left ventricular (LV) mechanical function.ResultsLA LGE images were acquired in 111 patients undergoing CMR imaging, including 66 patients with no prior history of an atrial arrhythmia. During the median follow-up of 2.7 years (interquartile range (IQR) 1.8–3.7 years), 15/66 (23%) of patients developed a new atrial arrhythmia. LA LGE ≥10% of LA myocardial volume was significantly associated with an increased rate of new-onset atrial arrhythmia, with a hazard ratio of 3.16 (95% CI 1.14–8.72), p = 0.026. There were significant relationships between LA LGE and both LA ejection fraction (r = − 0.39, p < 0.0005) and echocardiographic LV septal e’ (r = − 0.24, p = 0.04) and septal E/e’ (r = 0.31, p = 0.007).ConclusionsElevated LA LGE is associated with reduced LA function and reduced LV diastolic function. LA LGE is associated with new onset atrial arrhythmia during follow-up.Electronic supplementary materialThe online version of this article (10.1186/s12968-018-0514-3) contains supplementary material, which is available to authorized users.

Refractive error (RE) is a complex, multifactorial disorder characterized by a mismatch between the optical power of the eye and its axial length that causes object images to be focused off the retina. The two major subtypes of RE are myopia (nearsightedness) and hyperopia (farsightedness), which represent opposite ends of the distribution of the quantitative measure of spherical refraction. We performed a fixed effects meta-analysis of genome-wide association results of myopia and hyperopia from 9 studies of European-derived populations: AREDS, KORA, FES, OGP-Talana, MESA, RSI, RSII, RSIII and ERF. One genome-wide significant region was observed for myopia, corresponding to a previously identified myopia locus on 8q12 (p = 1.25×10−8), which has been reported by Kiefer et al. as significantly associated with myopia age at onset and Verhoeven et al. as significantly associated to mean spherical-equivalent (MSE) refractive error. We observed two genome-wide significant associations with hyperopia. These regions overlapped with loci on 15q14 (minimum p value = 9.11×10−11) and 8q12 (minimum p value 1.82×10−11) previously reported for MSE and myopia age at onset. We also used an intermarker linkage- disequilibrium-based method for calculating the effective number of tests in targeted regional replication analyses. We analyzed myopia (which represents the closest phenotype in our data to the one used by Kiefer et al.) and showed replication of 10 additional loci associated with myopia previously reported by Kiefer et al. This is the first replication of these loci using myopia as the trait under analysis. “Replication-level” association was also seen between hyperopia and 12 of Kiefer et al.'s published loci. For the loci that show evidence of association to both myopia and hyperopia, the estimated effect of the risk alleles were in opposite directions for the two traits. This suggests that these loci are important contributors to variation of refractive error across the distribution.

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12121027/-/DC1.

Time-resolved MRA is a useful technique with many clinical applications.