nnResting state fMRI scanner instabilities revealed by longitud inal phantom scans in a multi-center study

Quality assurance (QA) is crucial in longitudinal and/or multi-site studies, which involve the collection of data from a group of subjects over time and/or at different locations. It is important to regularly monitor the performance of the scanners over time and at different locations to detect and control for intrinsic differences (e.g., due to manufacturers) and changes in scanner performance (e.g., due to gradual component aging, software and/or hardware upgrades, etc.). As part of the Ontario Neurodegenerative Disease Research Initiative (ONDRI) and the Canadian Biomarker Integration Network in Depression (CAN-BIND), QA phantom scans were conducted approximately monthly for three to four years at 13 sites across Canada with 3T research MRI scanners. QA parameters were calculated for each scan using the functional Biomarker Imaging Research Network\u27s (fBIRN) QA phantom and pipeline to capture between- and within-scanner variability. We also describe a QA protocol to measure the full-width-at-half-maximum (FWHM) of slice-wise point spread functions (PSF), used in conjunction with the fBIRN QA parameters. Variations in image resolution measured by the FWHM are a primary source of variance over time for many sites, as well as between sites and between manufacturers. We also identify an unexpected range of instabilities affecting individual slices in a number of scanners, which may amount to a substantial contribution of unexplained signal variance to their data. Finally, we identify a preliminary preprocessing approach to reduce this variance and/or alleviate the slice anomalies, and in a small human data set show that this change in preprocessing can have a significant impact on seed-based connectivity measurements for some individual subjects. We expect that other fMRI centres will find this approach to identifying and controlling scanner instabilities useful in similar studies

Probabilistic Phylogenetic Inference with Insertions and Deletions

A fundamental task in sequence analysis is to calculate the probability of a multiple alignment given a phylogenetic tree relating the sequences and an evolutionary model describing how sequences change over time. However, the most widely used phylogenetic models only account for residue substitution events. We describe a probabilistic model of a multiple sequence alignment that accounts for insertion and deletion events in addition to substitutions, given a phylogenetic tree, using a rate matrix augmented by the gap character. Starting from a continuous Markov process, we construct a non-reversible generative (birth–death) evolutionary model for insertions and deletions. The model assumes that insertion and deletion events occur one residue at a time. We apply this model to phylogenetic tree inference by extending the program dnaml in phylip. Using standard benchmarking methods on simulated data and a new “concordance test” benchmark on real ribosomal RNA alignments, we show that the extended program dnamlε improves accuracy relative to the usual approach of ignoring gaps, while retaining the computational efficiency of the Felsenstein peeling algorithm

Stemless shoulder arthroplasty: current status

BACKGROUND: Since the original Neer humeral replacement in the 1950s, the standard primary anatomic total shoulder arthroplasty design has slowly evolved. Most recently, the humeral stem has become progressively shorter to help combat stem-related complications. Currently, there are several companies who have developed and marketed a stemless humeral arthroplasty component. MATERIALS AND METHODS: Manufacturers\u27 data for 5 stemless shoulder arthroplasty components currently on the market were analyzed and reviewed. A literature review of short-term results for stemless shoulder arthroplasty was completed. RESULTS: Of the stemless shoulder arthroplasty systems available on the market, 3 are currently undergoing clinical trials in the United States. The Tornier Simpliciti (Tornier, Edina, MN, USA) clinical trial began in 2011. The study with 2-year minimum follow-up results is scheduled for completion in November 2014. The Arthrex Eclipse (Arthrex, Naples, FL, USA) clinical trial was started in January 2013. The tentative study completion date is 2017. The Biomet Nano (Biomet, Warsaw, IN, USA) clinical trial began in October 2013 and also has a tentative completion date of 2017. No other clinical trial is currently under way in the United States. Early results for stemless shoulder arthroplasty indicate clinical results similar to standard stemmed shoulder arthroplasty. Radiographic analysis indicates implant stability without migration or subsidence at 2- to 3-year minimum follow-up.. CONCLUSIONS: Several stemless shoulder arthroplasty implants are available outside the United States. Early clinical and radiographic results are promising, but well-designed clinical studies and midterm results are lacking. Three clinical trials are currently under way in the United States with initial availability for use anticipated in 2015

Stemless shoulder arthroplasty-current results and designs

Stemless shoulder arthroplasty was originally introduced in 2004 by a single manufacturer. Now, over a decade later, numerous designs are available outside the USA, but as yet, only one implant has been cleared by the Food and Drug Administration (FDA) and is available for use within the USA. Often referred to as canal sparing, these implants are designed for metaphyseal fixation to minimize humeral bone removal, avoid intraoperative and postoperative humeral fracture complications, and to decrease morbidity associated with revision operations. Recently, the second generation of stemless arthroplasty, a convertible implant allowing use in either anatomic or reverse arthroplasty configuration, was released for use outside the USA. This paper will review the available designs, reported results, and raise potential concerns for this emerging technology

Quantification of B2 glenoid morphology in total shoulder arthroplasty

BACKGROUND: B2 glenoid morphology is challenging to address with shoulder reconstruction. Deformity often renders current techniques inadequate, necessitating compromises that limit long-term implant durability. The purpose of this study was to perform in vivo measurements of glenoid deformity to better appreciate the orientation of the B2 biconcavity demarcation and erosion that surgeons face intraoperatively. MATERIALS AND METHODS: A consecutive 106 total shoulder arthroplasty cases for primary glenohumeral osteoarthritis were studied. We classified glenoids by direct visualization and noted lines of biconcavity demarcation and erosion in B2s. We then calculated the angle of erosion as that between the back side of the unsupported, smooth-backed glenoid sizer disk and the neoglenoid. We obtained depth measurements throughout the reaming process and monitored subchondral bone. RESULTS: We classified 43 of 106 glenoids (41%) as B2. A biconcavity demarcation line between the paleoglenoid and the neoglenoid was present, on average, from the 1-o\u27clock to the 7-o\u27clock position for a left shoulder. Mean depth of erosion was 4.4 mm, occurring at 114° on a Cartesian coordinate system for a left shoulder. The mean angle of erosion was 18° (range, 8°-43°). Despite reaming, 20 of 43 B2 glenoids (47%) had incompletely supported components at final seating. CONCLUSIONS: Arthritic B2 glenoids are common, and their maximal erosion is usually posteroinferior. Use of standard glenoid components to reconstruct them may require significant subchondral bone removal to achieve complete bone support. Alternatively, as a compromise, maintenance of subchondral bone in these cases requires implanting components with incomplete bony support

Asynchronous Web-Based Patient-Centered

A web-based system for asynchronous multimedia messaging between shoulder replacement surgery patients at home and their surgeons was developed and tested. A web browser plug-in simplifies the process of capturing video and transferring it to a web site for novice computer users. The design of the video capture plug-in can be reused to acquire and securely transfer any type of data over the web. For example, readings from home biosensor instruments (e.g., glucometers and spirometers) that can be connected to a personal computer can be transferred to a home telemedicine web site. Both patients and doctors can access this web site to monitor health status longitudinally. Six patients, whose familiarity with computers ranged from no experience to expert users, used the system. All of the subjects were able to use the system to check treatment reminders and to send at least one message with video to their surgeons. The surgeons monitored the system regularly and always responded to messages within 24 h during the six-month trial period

Clinical and radiographic outcomes of the simpliciti canal-sparing shoulder arthroplasty system: a prospective two-year multicenter study

BACKGROUND: Stemmed humeral components have been used since the 1950s; canal-sparing (also known as stemless) humeral components became commercially available in Europe in 2004. The Simpliciti total shoulder system (Wright Medical, formerly Tornier) is a press-fit, porous-coated, canal-sparing humeral implant that relies on metaphyseal fixation only. This prospective, single-arm, multicenter study was performed to evaluate the two-year clinical and radiographic results of the Simpliciti prosthesis in the U.S. METHODS: One hundred and fifty-seven patients with glenohumeral arthritis were enrolled at fourteen U.S. sites between July 2011 and November 2012 in a U.S. Food and Drug Administration (FDA) Investigational Device Exemption (IDE)-approved protocol. Their range of motion, strength, pain level, Constant score, Simple Shoulder Test (SST) score, and American Shoulder and Elbow Surgeons (ASES) score were compared between the preoperative and two-year postoperative evaluations. Statistical analyses were performed with the Student t test with 95% confidence intervals. Radiographic evaluation was performed at two weeks and one and two years postoperatively. RESULTS: One hundred and forty-nine of the 157 patients were followed for a minimum of two years. The mean age and sex-adjusted Constant, SST, and ASES scores improved from 56% preoperatively to 104% at two years (p \u3c 0.0001), from 4 points preoperatively to 11 points at two years (p \u3c 0.0001), and from 38 points preoperatively to 92 points at two years (p \u3c 0.0001), respectively. The mean forward elevation improved from 103° ± 27° to 147° ± 24° (p \u3c 0.0001) and the mean external rotation, from 31° ± 20° to 56° ± 15° (p \u3c 0.0001). The mean strength in elevation, as recorded with a dynamometer, improved from 12.5 to 15.7 lb (5.7 to 7.1 kg) (p \u3c 0.0001), and the mean pain level, as measured with a visual analog scale, decreased from 5.9 to 0.5 (p \u3c 0.0001). There were three postoperative complications that resulted in revision surgery: infection, glenoid component loosening, and failure of a subscapularis repair. There was no evidence of migration, subsidence, osteolysis, or loosening of the humeral components or surviving glenoid components. CONCLUSIONS: The study demonstrated good results at a minimum of two years following use of the Simpliciti canal-sparing humeral component. Clinical results including the range of motion and the Constant, SST, and ASES scores improved significantly, and radiographic analysis showed no signs of loosening, osteolysis, or subsidence of the humeral components or surviving glenoid components. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence