Quantitative contrast enhanced dual energy CT to predict avascular necrosis: a feasibility study of proximal humerus fractures.

BACKGROUND: Avascular necrosis is a delayed complication of proximal humerus fractures that increases the likelihood of poor clinical outcomes. CT scans are routinely performed to guide proximal humerus fracture management. We hypothesized iodine concentration on post-contrast dual energy CT scans identifies subjects who develop avascular necrosis and ischemia due to compromised blood flow. MATERIALS AND METHODS: 55 patients with proximal humerus fractures enrolled between 2014 and 2017 underwent clinical, radiographic and contrast enhanced dual energy CT assessment. Iodine densities of the humeral head and the glenoid (control) were measured on CT. Subjects managed with open reduction internal fixation or conservatively (non-surgical) were followed for up to two years for radiographic evidence of avascular necrosis. Arthroplasty subjects underwent histopathologic evaluation for ischemia of the resected humeral head. RESULTS: 17 of 55 subjects (30.9%) were treated conservatively, 21 (38.2%) underwent open reduction internal fixation and 17 of 55 (30.9%) underwent arthroplasty. Of the 38 subjects treated conservatively or with ORIF, 20 (52.6%) completed 12 months of follow up and 14 (36.8%) 24 months of follow up. At 12 months follow up, two of 20 subjects (10%) and at 24 months 3 of 14 subjects (21.4%) developed avascular necrosis. At 12 months, the mean humerus/glenoid iodine ratio was 1.05 (standard deviation 0.24) in subjects with AVN compared to 0.91 (0.24) in those who did not. At 24 months, subjects with avascular necrosis had a mean humerus/glenoid iodine concentration ratio of 1.06 (0.17) compared to 0.924 (0.21) in those who did not. Of 17 arthroplasty subjects, 2 had severe ischemia and an iodine ratio of 1.08 (0.30); 5 had focal ischemia and a ratio of 1.00 (0.36); and 8 no ischemia and a ratio of 0.83 (0.08). CONCLUSIONS: Quantifying iodine using dual energy CT in subjects with proximal humerus fractures is technically feasible. Preliminary data suggest higher humeral head iodine concentration may increase risk of avascular necrosis; however, future studies must enroll and follow enough subjects managed with open reduction internal fixation or conservatively for two or more years to provide statistically significant results. Trial Registrations NCT02170545 registered June 23, 2014, ClinicalTrials.gov.

Reliability of meniscus tear description: a study using MRI from the Osteoarthritis Initiative.

Despite being one of the most common indications for surgery, data on the types of meniscus tear that should be treated surgically are limited. Improving patient selection requires agreement on meniscus tear description. This study evaluates a simple MRI tear classification system for inter-observer agreement. Knee MRI examinations from 57 subjects from the Osteoarthritis Initiative cohort were reviewed by two sub-specialty trained, musculoskeletal radiologists. Based on two pulse sequences, each meniscus was classified by: tear or no tear; location of tear in anterior, middle or posterior third or multiple thirds; and displaced or non-displaced radial, horizontal, longitudinal or complex tear pattern. A tear was defined as signal abnormality extending to the surface on at least two images and displacement as more than 2 mm of extrusion or separation measured orthogonal to the tear plane. Kappa, weighted Kappa and percentage agreement were calculated. For the medial meniscus, Kappa and percentage agreement estimates were, respectively: the presence of tear, 0.79 and 89.5%; tear with displacement, 0.70 (weighted Kappa) and 66.0%; tear description, 0.47 and 61.4%; tear location, 0.64 and 79.0%. For the lateral meniscus, estimates were: the presence of tear, 0.75 and 89.5%; tear with displacement, 0.81 (weighted Kappa) and 86.0%; tear description, 0.56 and 78.9%; tear location, 0.74 and 87.7%. The strength of agreement between readers was moderate to substantial underscoring the challenge of meniscus tear classification.

Correlation between the accessory anterolateral talar facet, bone marrow edema, and tarsal coalitions.

OBJECTIVE: The purposes of this study was to determine the prevalence of the accessory anterolateral talar facet (AALTF); to evaluate the relationship between AALTF, focal abutting bone marrow edema (FABME), and sinus tarsi edema; and to study the prevalence of tarsal coalitions in patients with the AALTF utilizing ankle MR images. MATERIALS AND METHODS: 5-T ankle MR images were reviewed for the presence of AALTF, FABME, sinus tarsi edema, tarsal coalition, and location and type of coalition (cartilaginous, fibrous, and osseous). Multivariate analysis was performed to examine the correlation between AALTF and the other variables. RESULTS: Three hundred ninety-one consecutive patients were included (age range 5-86 years; mean age 45 years). An AALTF was present in 3.6% (14/391) of patients. The AALTF prevalence was 2% in women and 6.6% in men. There was a significantly association between AALTF and FABME (9/14, p < 0.05), sinus tarsi edema (13/14, p < 0.05), and tarsal coalition (4/14, p < 0.05). CONCLUSION: AALTF is relatively often detected on MRI of the ankle and significantly associated with BME, sinus tarsi edema, and subtalar coalition. Patients with a tarsal coalition should be evaluated for the concurrent presence of an AALTF.

Magnetic resonance imaging of patellofemoral osteoarthritis: intertester reliability and associations with knee pain and function.

OBJECTIVES: We examined the intertester reliability of patellofemoral compartment (PFC) osteoarthritis (OA) severity using magnetic resonance images (MRI) and a modified Kellgren and Lawrence (K&L) system. Second, we determined if these grades were associated with clinical tests of PFC involvement or self-reported pain/difficulty with stair climbing. Third, we assessed the association between PFC OA severity and knee pain or disability, after accounting for potential confounders including tibiofemoral OA severity. METHOD: We examined the 9-year Osteoarthritis Initiative data from 114 subjects in the year prior to undergoing knee arthroplasty. The weighted kappa (κw) was used to determine intertester reliability, and the Pearson chi-square was used to assess associations among PFC OA scores and clinical tests. Multiple regressions were used to determine independent associations between self-reported pain/function and PFC OA. RESULTS: Reliability was substantial (κw = 0.73 (SE = 0.05)). Chi-square associations between PFC OA severity and clinical tests were not significant (p > 0.05). Multiple regression models between PFC OA and self-reported pain or function scores were not significant (p > 0.05). CONCLUSIONS: MRI-based measures of PFC OA were highly reliable indicating that musculoskeletal radiologists can reliably grade the PFCs of subjects using MRI. The extent of PFC OA is not associated with either clinical tests of PFC involvement or activities associated with PFC pain in persons with moderate to severe symptomatic tibiofemoral and PFC OA.

Source-to-detector distance and beam center do not affect radiographic measurements of acetabular morphology.

OBJECTIVE: Multiple radiographic acquisition techniques have been evaluated for their effect on measurements of acetabular morphology. This cadaveric study examined the effect of two acquisition parameters not previously evaluated: beam center position and source-to-detector distance. This study also evaluated the effect of reader differences on measurements. METHODS: Following calibration of measurements between two readers using five clinical radiographs (training), radiographs were obtained from two cadavers using four different source-to-detector distances and three different radiographic centers for a total of 12 radiographic techniques (experimental). Two physician readers acquired four types of measurements from each cadaver radiograph: lateral center edge angle, peak-to-edge distance, Sharp's angle, and the Tonnis angle. All measurements were evaluated for intra-class correlation coefficient (ICC), kappa statistics for hip dysplasia, and factors that resulted in measurement differences using a mixed statistical model. RESULTS: After training of the two physician readers, there was strong agreement in their hip morphology measurements (ICC 0.84-0.93), agreement in the presence of hip dysplasia (κ = 0.58-1.0), and no measurement difference between physician readers (p = 0.12-1.0). Experimental cadaver measurements showed moderate-to-strong agreement of the readers (ICC 0.74-0.93) and complete agreement on dysplasia (κ = 1). After accounting for reader and radiographic technique, there was no difference in hip morphology measurements (p = 0.83-0.99). CONCLUSIONS: In this cadaveric study, measurements of hip morphology were not affected by varying source-to-detector distance or beam center. We conclude that these acquisition parameters are not likely to affect the diagnosis of hip dysplasia in a clinical setting.

Drosophila Yurt is a new protein-4.1-like protein required for epithelial morphogenesis.

Proteins of the 4.1 family play a key role in the integrity of the cytoskeleton and in epithelial tissue movement, as shown by the disruption of the actin cytoskeleton in human erythrocytes caused by genetic loss of protein 4.1, and the failure of epithelial tissue migration during Drosophila embryogenesis caused by genetic loss of the 4.1 homolog Coracle. Here we report the genetic characterization of Yurt, a novel protein 4.1 family member in Drosophila that is associated with the plasma membrane of epithelial cells. Homozygous loss-of-function mutations in the yurt gene cause failure of germ-band retraction, dorsal closure, and head involution, associated with degeneration of the amnioserosa and followed by embryonic lethality. A mammalian homolog of Yurt is up-regulated in metastatic melanoma cells. These novel cytoskeletal proteins appear to play important roles in epithelial cell movements and in the morphogenetic tissue changes that depend on them.