Diagnostic Performance of Dynamic Contrast-Enhanced 3T MR Imaging for Characterization of Orbital Lesions: Validation in a Large Prospective Study.

BACKGROUND AND PURPOSE: Orbital lesions are rare but serious. Their characterization remains challenging. Diagnosis is based on biopsy or surgery, which implies functional risks. It is necessary to develop noninvasive diagnostic tools. The goal of this study was to evaluate the diagnostic performance of dynamic contrast-enhanced MR imaging at 3T when distinguishing malignant from benign orbital tumors on a large prospective cohort. MATERIALS AND METHODS: This institutional review board-approved prospective single-center study enrolled participants presenting with an orbital lesion undergoing a 3T MR imaging before surgery from December 2015 to May 2021. Morphologic, diffusion-weighted, and dynamic contrast-enhanced MR images were assessed by 2 readers blinded to all data. Univariable and multivariable analyses were performed. To assess diagnostic performance, we used the following metrics: area under the curve, sensitivity, and specificity. Histologic analysis, obtained through biopsy or surgery, served as the criterion standard for determining the benign or malignant status of the tumor. RESULTS: One hundred thirty-one subjects (66/131 [50%] women and 65/131 [50%] men; mean age, 52 [SD, 17.1] years; range, 19-88 years) were enrolled. Ninety of 131 (69%) had a benign lesion, and 41/131 (31%) had a malignant lesion. Univariable analysis showed a higher median of transfer constant from blood plasma to the interstitial environment (K trans) and of transfer constant from the interstitial environment to the blood plasma (minute-1) (Kep) and a higher interquartile range of K trans in malignant-versus-benign lesions (1.1 minute-1 versus 0.65 minute-1, P = .03; 2.1 minute-1 versus 1.1 minute-1, P = .01; 0.81 minute-1 versus 0.65 minute-1, P = .009, respectively). The best-performing multivariable model in distinguishing malignant-versus-benign lesions included parameters from dynamic contrast-enhanced imaging, ADC, and morphology and reached an area under the curve of 0.81 (95% CI, 0.67-0.96), a sensitivity of 0.82 (95% CI, 0.55-1), and a specificity of 0.81 (95% CI, 0.65-0.96). CONCLUSIONS: Dynamic contrast-enhanced MR imaging at 3T appears valuable when characterizing orbital lesions and provides complementary information to morphologic imaging and DWI.

Relative impact of hospital and surgeon procedure volumes on primary total hip arthroplasty revision: a nationwide cohort study in France.

BACKGROUND: Both surgeon and hospital procedure volumes have been found to be associated with total hip arthroplasty (THA) outcomes. However, little research has been conducted on the relative influence. We studied the association between THA survivorship and both hospital and surgeon procedure volumes, considering their relative impact. METHODS: A population-based cohort included all patients aged ≥40 years having received a unilateral primary THA from 2010 to 2011, from the French National Health Insurance Database. Patients were followed up until the end of 2014. The outcome was THA revision. Exposures of interest were procedure volumes, divided into tertiles: <1.5, 1.5-4, >4 and <7, 7-15, >15 procedures per month defined as low, medium, and high volumes for surgeon and hospital, respectively. RESULTS: The cohort had 62,906 patients, with mean age 69 years and women 57%. Mean surgeon and hospital volumes were 8 and 23 procedures per month, respectively, and 5%, 72%, 22% and 7%, 28%, 65% of THAs were implanted by a low-, medium-, and high-volume surgeon or in a low-, medium-, and high-volume hospital, respectively. Median follow-up was 45 months (range, 0-57 months). In multivariate analysis, adjusted for both surgeon and hospital volumes, for patient and THA characteristics, a lower surgeon volume was associated with poorer THA survivorship (adjusted hazard ratio [aHR] = 1.19; 95% confidence interval [CI], 1.07-1.34 and aHR = 1.70; 95% CI, 1.40-2.05, for medium- and low-volume surgeon, respectively, compared with that of high volume), whereas hospital volume was not. CONCLUSIONS: This study brings evidence to support the notion that THAs performed by high-volume surgeons in French private hospitals have higher survivorship in the first 4 years.

Development and validation of an ELISA method for the quantification of nivolumab in plasma from non-small-cell lung cancer patients.

Nivolumab, an anti PD-1 monoclonal antibody, has been approved for the treatment of previously treated advanced or metastatic non-small-cell lung cancer (NSCLC). The aim of this study was to develop and validate an ELISA method for the quantification of nivolumab in plasma from patients with NSCLC in order to perform future pharmacokinetic/pharmacodynamic (PK/PD) studies. A home-made ELISA was developed and validated according to the general recommendations for the immunoassays. Then, the ELISA method was applied to quantify plasma trough levels (Cmin) of nivolumab (3mg/kg every two weeks) in 27 NSCLC patients at days 14, 28 and 42 after start of treatment. Blood samples were collected just before the infusion on days 0 (baseline), 14, 28 and 42 after start of treatment. The dynamic calibration range for nivolumab assay was 5-100µg/mL. Within- and between-day imprecision for quality controls (5, 20 and 75µg/mL) were less than 5 and 12%, respectively. The mean (±standard deviation) nivolumab Cmin was 17.3±4.8µg/mL (coefficient of variation, CV=27.8%), 25.0±9.7µg/mL (CV=38.8%) and 33.0±12.9µg/mL (CV=39.1%) on days 14, 28 and 42, respectively. IgG (p=0.002) and ALT (p=0.041) were independently associated with plasma nivolumab Cmin at day 42. The present ELISA method for quantification of nivolumab in plasma from NSCLC patients is sensitive and accurate enough to be used for further PK/PD investigations.