Gender and age differences in the associations between cortical thickness and hand osteoarthritis severity: data from the Osteoarthritis Initiative.

OBJECTIVE: To evaluate gender differences in the association between metacarpal cortical thickness (Tcort)-a surrogate for bone density-and severity of radiographic hand osteoarthritis (HOA) in a longitudinal observational study. METHOD: Hand radiographs of 3575 participants (2039 F/1536 M) from the Osteoarthritis Initiative were assessed at baseline and 48 months. A reader used a semi-automated software tool to calculate Tcort, a measurement of the cortical thickness, for metacarpals 2-4. Average Tcort at baseline and change in Tcort from baseline to 48 months was determined and stratified by gender and age for 7 5-year age groups. Spearman's rank correlation coefficients were calculated for the association of baseline Tcort and 2 measures of baseline HOA severity: the sum of Kellgren-Lawrence (KL) grade and total number of joints with radiographic HOA. Longitudinally, logistic regression was used to assess the relationship of Tcort loss to new finger joint radiographic HOA, increase in KL grades, and incident hand pain. RESULTS: Male Tcort was higher than females. Significant correlations between Tcort and radiographic severity were noted for women but not men, with stronger associations among women >60 years (rho = -0.25; 95% confidence interval (CI) = -0.31 to -0.19). Statistically significant associations were seen between Tcort change and radiographic osteoarthritis change among women but not men, with substantial gender differences for Tcort change, particularly ages 50 to 70 years (p < 0.01; e.g., Tcort change ages 55 to <60: males = -0.182 (0.118), females = -0.219 (0.124)). CONCLUSION: We found significant HOA-related gender differences in Tcort, suggesting the involvement of female bone loss during and after menopause.

Associations of inflammatory and metabolic biomarkers with incident erosive hand osteoarthritis in the osteoarthritis initiative cohort.

OBJECTIVE: Erosive hand osteoarthritis (eHOA) is a subtype of hand osteoarthritis (OA) that develops in finger joints with pre-existing OA and is differentiated by clinical characteristics (hand pain/disability, inflammation, and erosions) that suggest inflammatory or metabolic processes. METHOD: This was a longitudinal nested case-cohort design among Osteoarthritis Initiative participants who had hand radiographs at baseline and 48-months, and biospecimens collected at baseline. We classified incident radiographic eHOA in individuals with ≥1 joint with Kellgren-Lawrence ≥2 and a central erosion present at 48-months but not at baseline. We used a random representative sample (n = 1282) for comparison. We measured serum biomarkers of inflammation, insulin resistance and dysglycemia, and adipokines using immunoassays and enzymatic colorimetric procedures, blinded to case status. RESULTS: Eighty-six participants developed incident radiographic eHOA. In the multivariate analyses adjusted for age, gender, race, smoking, and body mass index, and after adjustment for multiple analyses, incident radiographic eHOA was associated with elevated levels of interleukin-7 (risk ratio (RR) per SD = 1.30 [95% confidence interval (CI) 1.09, 1.55] p trend 0.01). CONCLUSION: This exploratory study suggests an association of elevated interleukin-7, an inflammatory cytokine, with incident eHOA, while other cytokines or biomarkers of metabolic inflammation were not associated. Interleukin-7 may mediate inflammation and tissue damage in susceptible osteoarthritic finger joints and participate in erosive progression.

Hand joints without radiographic osteoarthritis maintain their joint space width over 4 years despite what's happening elsewhere in the hand.

OBJECTIVES: We aimed to determine if hand osteoarthritis is characterized by systemic cartilage loss by assessing if radiographically normal joints had greater joint space width (JSW) loss during four years in hands with incident or prevalent osteoarthritis elsewhere in the hand compared with hands without osteoarthritis. METHODS: We used semi-automated software to measure JSW in the distal and proximal interphalangeal joints of 3,368 participants in the Osteoarthritis Initiative who had baseline and 48-month hand radiographs. A reader scored 16 hand joints (including the thumb-base) for Kellgren-Lawrence (KL) Grade. A joint had osteoarthritis if scored as KL ≥ 2. We identified three groups based on longitudinal hand osteoarthritis status: 1) no hand osteoarthritis (KL < 2 in all 16 joints) at the baseline and 48-month visits, 2) incident hand osteoarthritis (KL < 2in all 16 joints at baseline and then ≥1 joint with KL ≥ 2 at 48-months), and 3) prevalent hand osteoarthritis (≥1 joint with KL ≥ 2 at baseline and 48-months). We then assessed if JSW in radiographically normal joints (KL = 0) differed across these three groups. We calculated unpooled effect sizes to help interpret the differences between groups. RESULTS: We observed small differences in JSW loss that are unlikely to be clinically important between radiographically normal joints between those without hand osteoarthritis (n = 1054) and those with incident (n = 102) or prevalent hand osteoarthritis (n = 2212) (effect size range: -0.01 to 0.24). These findings were robust when examining JSW loss dichotomized based on meaningful change and in other secondary analyses. CONCLUSIONS: Hand osteoarthritis is not a systemic disease of cartilage.

Statistical information about reward timing is insufficient for promoting optimal persistence decisions.

When deciding how long to keep waiting for delayed rewards that will arrive at an uncertain time, different distributions of possible reward times dictate different optimal strategies for maximizing reward. When reward timing distributions are heavy-tailed (e.g., waiting on hold) there is a point at which waiting is no longer advantageous because the opportunity cost of waiting is too high. Alternatively, when reward timing distributions have more predictable timing (e.g., uniform), it is advantageous to wait as long as necessary for the reward. Although people learn to approximate optimal strategies, little is known about how this learning occurs. One possibility is that people learn a general cognitive representation of the probability distribution that governs reward timing and then infer a strategy from that model of the environment. Another possibility is that they learn an action policy in a way that depends more narrowly on direct task experience, such that general knowledge of the reward timing distribution is insufficient for expressing the optimal strategy. Here, in a series of studies in which participants decided how long to persist for delayed rewards before quitting, we provided participants with information about the reward timing distribution in several ways. Whether the information was provided through counterfactual feedback (Study 1), previous exposure (Studies 2a and 2b), or description (Studies 3a and 3b), it did not obviate the need for direct, feedback-driven learning in a decision context. Therefore, learning when to quit waiting for delayed rewards might depend on task-specific experience, not solely on probabilistic reasoning.

Automatic Measuring of Finger Joint Space Width on Hand Radiograph using Deep Learning and Conventional Computer Vision Methods.

Hand osteoarthritis (OA) severity can be assessed visually through radiographs using semi-quantitative grading systems. However, these grading systems are subjective and cannot distinguish minor differences. Joint space width (JSW) compensates for these disadvantages, as it quantifies the severity of OA by accurately measuring the distances between joint bones. Current methods used to assess JSW require users' interaction to identify the joints and delineate initial joint boundary, which is time-consuming. To automate this process and offer a more efficient and robust measurement for JSW, we proposed two novel methods to measure JSW: 1) The segmentation-based (SEG) method, which uses traditional computer vision techniques to calculate JSW; 2) The regression-based (REG) method, which is a deep learning approach employing a modified VGG-19 network to predict JSW. On a dataset with 3,591 hand radiographs, 10,845 DIP joints were cut as regions of interest and served as input to the SEG and REG methods. The bone masks of the ROI images generated by a U-Net model were sent as input in addition to the ROIs. The ground truth of JSW was labeled by a trained research assistant using a semi-automatic tool. Compared with the ground truth, the REG method achieved a correlation coefficient of 0.88 and mean square error (MSE) of 0.02 mm on the testing set; the SEG method achieved a correlation coefficient of 0.42 and MSE of 0.15 mm. Results show the REG method has promising performance in automatic JSW measurement and in general, Deep Learning approaches can facilitate the automatic quantification of distance features in medical images.

Racket or Bat Sports: No Association With Thumb-Base Osteoarthritis.

CONTEXT: Repetitive joint use is a risk factor for osteoarthritis, which is a leading cause of disability. Sports requiring a racket or bat to perform repetitive high-velocity impacts may increase the risk of thumb-base osteoarthritis. However, this hypothesis remains untested. OBJECTIVE: To determine if a history of participation in racket or bat sports was associated with the prevalence of thumb-base osteoarthritis. DESIGN: Descriptive epidemiologic study. SETTING: Four US clinical sites associated with the Osteoarthritis Initiative. PATIENTS OR OTHER PARTICIPANTS: We recruited 2309 men and women from the community. Eligible participants had dominant-hand radiographic readings, hand symptom assessments, and historical physical activity survey data. MAIN OUTCOME MEASURE(S): A history of exposure to racket or bat sports (badminton, baseball or softball, racketball or squash, table tennis [or ping pong], tennis [doubles], or tennis [singles]) was based on self-reported recall data covering 3 age ranges (12-18, 19-34, and 35-49 years). Prevalent radiographic thumb-base osteoarthritis was defined as Kellgren-Lawrence grade >2 in the first carpometacarpal joint or scaphotrapezoidal joint at the Osteoarthritis Initiative baseline visit. Symptomatic thumb-base osteoarthritis was defined as radiographic osteoarthritis and hand or finger symptoms. RESULTS: Radiographic or symptomatic thumb-base osteoarthritis was present in 355 (34%) and 56 (5%), respectively, of men (total = 1049) and 535 (42%) and 170 (13%), respectively, of women (total = 1260). After adjusting for age, race, and education level, we found no significant associations between a history of any racket or bat sport participation and thumb-base osteoarthritis (radiographic or symptomatic; odds ratios ranged from 0.82 to 1.34). CONCLUSIONS: In a community-based cohort, a self-reported history of participation in racket or bat sports was not associated with increased odds of having radiographic or symptomatic thumb-base osteoarthritis in the dominant hand.

Prevalence, Incidence, and Progression of Radiographic and Symptomatic Hand Osteoarthritis: The Osteoarthritis Initiative.

OBJECTIVE: To describe the prevalence, incidence, and progression of radiographic and symptomatic hand osteoarthritis (OA), and to evaluate differences according to age, sex, race, and other risk factors. METHODS: Participants were assessed for radiographic and symptomatic hand OA at baseline and year 4 to determine incident disease. A modified Poisson regression with a robust variance estimator was used to account for clustering of joints within fingers within persons to estimate the prevalence ratios and relative risk estimates associated with participant characteristics. RESULTS: Among 3,588 participants, the prevalence of radiographic hand OA was 41.4%, and the prevalence of symptomatic hand OA was 12.4%. The incidence over 48 months was 5.6% for radiographic hand OA and 16.9% for symptomatic hand OA. Over 48 months, 27.3% of the participants exhibited OA progression. We found complex differences by age, sex, and race, with increasing rates of prevalent hand OA with older age in both men and women, but with rates of incident disease peaking at ages 55-64 years in women. Women had higher rates of symptomatic hand OA, but only nonsignificantly higher rates of incident radiographic hand OA, than men. Women more frequently had distal interphalangeal joint disease, while men more frequently had metacarpophalangeal joint OA. Black men and women had lower rates of hand OA than White participants, but Black men had higher rates of prevalent hand OA than Black women at younger ages. CONCLUSION: Hand OA is a heterogeneous disease with complex differences by age, sex, race, hand symptoms, and patterns of specific joints affected. Further research investigating the mechanisms behind these differences, whether mechanical, metabolic, hormonal, or constitutional, is warranted.

Erosive Hand Osteoarthritis: Incidence and Predictive Characteristics Among Participants in the Osteoarthritis Initiative.

OBJECTIVE: To evaluate age, sex, race, osteoarthritis (OA) severity, metabolic factors, and bone health as risk factors for erosive hand OA at baseline and its incidence over a 48-month period. METHODS: This was a longitudinal cohort study that included participants from the Osteoarthritis Initiative (OAI) with complete hand radiographs from baseline and 48-month visits who were eligible at baseline for incident erosive hand OA (i.e., had or were at risk for knee OA [criterion for OAI inclusion] and did not currently have erosive hand OA). Individuals were classified as having erosive hand OA if the Kellgren/Lawrence (K/L) grade was ≥2 in at least 1 interphalangeal joint on 2 different fingers and central erosion was present in at least 1 joint. RESULTS: Of the 3,365 individuals without prevalent erosive hand OA at baseline, 86 (2.6%) developed erosive hand OA during the 48-month period. Risk factors included older age (relative risk [RR] per SD 1.63 [95% confidence interval 1.35-1.97]), female sex (RR 2.47 [95% confidence interval 1.52-4.02]), greater OA severity (sum K/L grade 13.9 versus 5.3; P < 0.001), and less cortical width (1.38 mm versus 1.52 mm; P < 0.001). After 48 months, subjects who had developed erosive hand OA were characterized by greater progression of radiographic OA (i.e., joint space narrowing, K/L grade progression [RR 1.35], and loss of cortical thickness [RR 1.23]), adjusted for age, sex, race, body mass index, and baseline OA severity (sum K/L grade). CONCLUSION: These findings demonstrate that erosive hand OA is more common in older women and is strongly associated with severity of articular structural damage and its progression. Individuals who develop erosive hand OA have thinner bones prior to erosive hand OA development and as it progresses, suggesting that erosive hand OA is a disorder of skeletal frailty.

Characteristics of Accelerated Hand Osteoarthritis: Data from the Osteoarthritis Initiative.

OBJECTIVE: We aimed to determine whether hand joints develop an accelerated form of osteoarthritis (OA) and to characterize individuals who develop accelerated hand osteoarthritis (AHOA). METHODS: We evaluated 3519 participants in the Osteoarthritis Initiative with complete data for baseline and 48-month radiographic hand osteoarthritis (HOA). One reader scored posteroanterior radiographs of the dominant hand using a modified Kellgren-Lawrence (KL) scale and another reader scored the presence of central or marginal erosions. A third reader read images flagged for signs of diseases other than OA. We defined AHOA as ≥ 1 joints that progressed from a KL grade of 0 or 1 at baseline to KL grade 3 or 4 at 48 months. RESULTS: The definition of AHOA was met by 1% over 4 years: 37 hands had 1 joint affected and 1 hand had 2 joints affected. At baseline, adults who developed AHOA were more likely to have hand pain (37% vs 22%), radiographic HOA (71% vs 36%), as well as central (22% vs 7%) and marginal erosions (11% vs 2%) in other joints compared to those without AHOA. Adults with AHOA were more likely to develop new erosions over 48 months (central 35%, marginal 5%) than those without AHOA (central 5%, marginal 1%). The most common locations of accelerated OA were the second metacarpophalangeal and first carpometacarpal joint. CONCLUSION: Accelerated OA can occur in the hand, especially among digits commonly used for pinching and fine motor skills.

The associations between radiographic hand osteoarthritis definitions and hand pain: data from the osteoarthritis initiative.

The goal of our study was to evaluate the associations between various definitions of radiographic hand osteoarthritis (OA) and self-reported hand pain. We conducted a cross-sectional study with 3604 participants from the Osteoarthritis Initiative (OAI). Posteroanterior radiographs of the dominant hand were read using a modified Kellgren-Lawrence (KL) scale. For our primary analysis, hand OA at person level was defined as two or more finger joints with KL grade 2 or higher. In addition, for the purpose of exploratory analyses, we explored more conservative definitions of hand OA as well as different sum scores and digit- and row-based scores. The majority of definitions of radiographic hand OA were statistically significantly associated with self-reported hand pain. In our main analysis, persons with two or more finger joints with KL grade > 2 were approximately two times more likely to self-report hand pain than persons without radiographic hand OA. Increasing KL grades and increasing number of joints affected lead to stronger associations. Almost all definitions of hand OA were related to pain. Individuals with more severely affected joints or with higher number of affected joints are more likely to report hand pain than their peers. Specifically, individuals with hand joints with KL 3 or 4 have the greatest likelihood of hand pain.

Hybrid MRI-Ultrasound acquisitions, and scannerless real-time imaging.

PURPOSE: To combine MRI, ultrasound, and computer science methodologies toward generating MRI contrast at the high frame rates of ultrasound, inside and even outside the MRI bore. METHODS: A small transducer, held onto the abdomen with an adhesive bandage, collected ultrasound signals during MRI. Based on these ultrasound signals and their correlations with MRI, a machine-learning algorithm created synthetic MR images at frame rates up to 100 per second. In one particular implementation, volunteers were taken out of the MRI bore with the ultrasound sensor still in place, and MR images were generated on the basis of ultrasound signal and learned correlations alone in a "scannerless" manner. RESULTS: Hybrid ultrasound-MRI data were acquired in eight separate imaging sessions. Locations of liver features, in synthetic images, were compared with those from acquired images: The mean error was 1.0 pixel (2.1 mm), with best case 0.4 and worst case 4.1 pixels (in the presence of heavy coughing). For results from outside the bore, qualitative validation involved optically tracked ultrasound imaging with/without coughing. CONCLUSION: The proposed setup can generate an accurate stream of high-speed MR images, up to 100 frames per second, inside or even outside the MR bore. Magn Reson Med 78:897-908, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Cerebral cavernous hemangiomas at 7 Tesla: initial experience.

RATIONALE AND OBJECTIVES: Cavernous malformations (cavernomas) occur in 0.4%-0.9% of the population. The most common symptoms of cavernous malformations are seizures. An improved detection of small cavernomas might possibly help to clarify cryptogenic seizures, which represent 30% of all seizures. The aim of this study was to evaluate the benefit of magnetic resonance imaging at a field strength of 7 T in the detection of cavernomas. MATERIALS AND METHODS: Ten consecutive patients with known cavernomas were enrolled in this study. First a T2*-weighted gradient echo sequence was performed at 1.5 T with a slice thickness of 6 mm in axial orientation. Subsequently, the examination was repeated at 7 T. Both examinations were independently read by two blinded senior neuroradiologists. Localization and dimension of the hypointensities were recorded. RESULTS: One additional hypointensity was detected in one patient, which was not visible in the 1.5 T examination even retrospectively. In another patient with known cavernomatosis, innumerable new small hypointense lesions were detected at 7 T. CONCLUSION: Our small series suggests that ultra-high-field magnetic resonance imaging at 7 T improves the detection of cavernomas.

An eight-channel phased array RF coil for spine MR imaging at 7 T.

OBJECTIVE: To develop a transmit/receive radiofrequency (RF) array for MR imaging of the human spine at 7 T. The prototype is characterized in simulations and bench measurements, and the feasibility of high-resolution spinal cord imaging at 7 T is demonstrated in in vivo images of volunteers. MATERIALS AND METHODS: The RF phased array consists of 8 overlapping surface loop coils with a dimension of 12 cm x 12 cm each. Bench measurements were obtained with a phantom made of body-simulating liquid and assessed with a network analyzer. For safety validation, numerical computations of the RF field distribution and the corresponding specific absorption rate were performed on the basis of 3 different human body models. In vivo images of 3 volunteers (2 with a documented scoliosis) were acquired using a 3D-FLASH sequence with a high spatial resolution of 0.57 mm isotropic. RESULTS: The 7 T transmit/receive RF coil could be easily integrated into the patient table for examinations of the cervicothoracic or thoracolumbosacral spine. Comparable results were found for all 3 numerical calculations using different human body models. Measurements of the g-factor indicated good image quality for parallel imaging acceleration factors up to 2.7 along the head-feet direction, which could be validated in the in vivo images. The in vivo images demonstrated very fine anatomic features such as the longitudinal ligaments or the venous drainage through the vertebral bodies. A largely homogeneous excitation over an extensive field-of-view of 40 cm could be obtained. CONCLUSIONS: These early results indicate that a multichannel transmit/receive phased array RF coil can be used for in vivo spine imaging at 7 T, thereby rendering high-resolution spine imaging a promising new application in 7 T clinical research.