A nonhuman primate model of age-related bone loss: a longitudinal study in male and premenopausal female rhesus monkeys.

Aging is associated with gradual bone loss in men and premenopausal women, with an accelerated rate of loss after menopause in women. Although many studies have investigated bone loss due to surgically induced estrogen depletion, little is known regarding normal age-related changes in bone mass in animal models. We used dual-energy X-ray absorptiometry (DXA) to measure bone mineral density (BMD), bone mineral content (BMC), and projected area (PA) at four skeletal sites over 4 years in 20 premenopausal female (8-23 years) and 29 male (8-27 years) rhesus monkeys (Macaca mulatta). Forearm BMD declined with age in both male and female monkeys. Lean mass was positively associated with BMD at all sites in males and with the distal radius in females. Serum osteocalcin declined and urinary cross-links increased with age in males but not females. Serum 25-hydroxyvitamin D concentrations decreased with age in females, and a similar trend was observed in males. In conclusion, an age-related decline in forearm BMD was observed in male and female rhesus monkeys. Total body BMC declined over time in older females, with a similar trend in males. Changes in markers of bone turnover with age were also observed in male monkeys. The results of this longitudinal study suggest that the rhesus monkey is a potential model for age-related changes in the human skeleton.

Interpretation of Emergency Department radiographs: a comparison of emergency medicine physicians with radiologists, residents with faculty, and film with digital display.

OBJECTIVE: We determined the relative value of teleradiology and radiology resident coverage of the emergency department by measuring and comparing the effects of physician specialty, training level, and image display method on accuracy of radiograph interpretation. MATERIALS AND METHODS: A sample of four faculty emergency medicine physicians, four emergency medicine residents, four faculty radiologists, and four radiology residents participated in our study. Each physician interpreted 120 radiographs, approximately half containing a clinically important index finding. Radiographs were interpreted using the original films and high-resolution digital monitors. Accuracy of radiograph interpretation was measured as the area under the physicians' receiver operating characteristic (ROC) curves. RESULTS: The area under the ROC curve was 0.15 (95% confidence interval [CI], 0.10-0.20) greater for radiologists than for emergency medicine physicians, 0.07 (95% CI, 0.02-0.12) greater for faculty than for residents, and 0.07 (95% CI, 0.02-0.12) greater for films than for video monitors. Using these results, we estimated that teleradiology coverage by faculty radiologists would add 0.09 (95% CI, 0.03-0.15) to the area under the ROC curve for radiograph interpretation by emergency medicine faculty alone, and radiology resident coverage would add 0.08 (95% CI, 0.02-0.14) to this area. CONCLUSION: We observed significant differences between the interpretation of radiographs on film and on digital monitors. However, we observed differences of equal or greater magnitude associated with the training level and physician specialty of each observer. In evaluating teleradiology services, observer characteristics must be considered in addition to the quality of image display.

Genealogy construction in a historically isolated population: application to genetic studies of rheumatoid arthritis in the Pima Indian.

PURPOSE: Due to the characteristics of complex traits, many traits may not be amenable to traditional epidemiologic methods. We illustrate an approach that defines an isolated population as the "unit" for carrying out studies of complex disease. We provide an example using the Pima Indians, a relatively isolated population, in which the incidence and prevalence of Type 2 diabetes, gallbladder disease, and rheumatoid arthritis (RA) are significantly increased compared with the general U.S. population. A previous study of RA in the Pima utilizing traditional methods failed to detect a genetic effect on the occurrence of the disease. METHODS: Our approach involved constructing a genealogy for this population and using a genealogic index to investigate familial aggregation. We developed an algorithm to identify biological relationships among 88 RA cases versus 4,000 subsamples of age-matched individuals from the same population. Kinship coefficients were calculated for all possible pairs of RA cases, and similarly for the subsamples. RESULTS: The sum of the kinship coefficient among all combination of RA pairs, 5.92, was significantly higher than the average of the 4,000 subsamples, 1.99 (p < 0.001), and was elevated over that of the subsamples to the level of second cousin, supporting a genetic effect in the familial aggregation. The mean inbreeding coefficient for the Pima was 0.00009, similar to that reported for other populations; none of the RA cases were inbred. CONCLUSIONS: The Pima genealogy can be anticipated to provide valuable information for the genetic study of diseases other than RA. Defining an isolated population as the "unit" in which to assess familial aggregation may be advantageous, especially if there are a limited number of cases in the study population.

The retained intrapericardial sponge: value of the lateral chest radiograph.

OBJECTIVE: Our objective was to identify reasons for the difficulty in diagnosing retained intrapericardial sponges and to determine ways to improve diagnostic accuracy. CONCLUSION: All three intrapericardially retained sponges were in the posterior pericardium, a region not visible to the surgeon. Radiographic detection of the sponges on standard anteroposterior projections is difficult because of exposure factors, other confusing linear markers, and metallic densities such as sternal sutures. However, knowledge of the typical location of a lost sponge and use of lateral radiographic projections may aid in early detection of this rare complication.

Rheumatoid arthritis in the Pima Indians: the intersection of epidemiologic, demographic, and genealogic data.

OBJECTIVE: To describe the clinical features and familial distribution of rheumatoid arthritis (RA) in the Pima Indians. METHODS: From 1965 through 1990, all cases of RA as defined by the American College of Rheumatology (formerly, the American Rheumatism Association) 1987 criteria or all cases of seropositive, erosive disease as defined by the Rome criteria were identified in individuals who were age 20 years and older and were of 50% or more Pima/Tohono-O'odham heritage. Radiographs were reviewed by 2 musculoskeletal radiologists who were blinded to case status. Kinship coefficients were used to evaluate familial aggregation. RESULTS: Eighty-eight RA cases were identified from this population-based sample. Over 66% of the cases had seropositive disease, over 60% had erosive disease, and over 40% had subcutaneous nodules. Of the 88 RA cases, 40 were members of families with more than 1 RA case. The remainder were simplex cases. CONCLUSION: In this population, clinical markers of severe RA were present in a majority of cases. The presence of familial aggregation for RA in the Pima Indians suggests underlying genetic factors in disease pathogenesis.

Utilization of computed tomography in patients hospitalized with community-acquired pneumonia.

The objective of the study was to assess the frequency of the use of chest computed tomography in 385 adults hospitalized with community-acquired pneumonia and determine whether the computed tomography examinations yielded additional diagnostic information. Also, if additional information was obtained, the study determined whether it changed the patient's treatment plan.

Establishing the level of digitization for wrist and hand radiographs for the third National Health and Nutrition Examination Survey.

In the third National Health and Nutrition Examination Survey (NHANES III) conducted by the National Center for Health Statistics, Centers for Disease Control and Prevention, radiographs of the hands and knees were taken of participants 60 years and older as part of the study of arthritis and musculoskeletal conditions. The purpose of the study was to decide the digitizing resolution to be used for these radiographs. A set of wrist and hand radiographs (N = 49) was graded by two radiologists for degree of bone erosions and served as a "gold standard." The radiographs were then digitized at three resolution levels; low-resolution 150 microns (2001 x 1634 x 12 bit matrix); intermediate-resolution 100 microns (3000 x 2400 x 12 bit matrix); and high-resolution 50 microns (4900 x 3000 x 12 bit matrix). A comparison of the digital images versus the gold standard reading was made at the three resolutions by two radiologists. Kappa statistics suggested fair (K > .4) to excellent (K > .75) agreement between the gold standard and the images at all levels. Intraclass correlation coefficient suggested high agreement between readers (ICC > .5), with minimal individual reader effect. Variance component estimates showed that the major contribution (78-83%) to scoring came from variability in the images themselves, not from the readers. The 100 microns resolution was selected over the 150 and 50 microns on the basis of practical considerations such as storage requirements, display time, and easier manipulation of the digital images by the readers.

Experimental testing of a DEXA-derived curved beam model of the proximal femur.

This study was designed to test whether, using curved beam theory, a structural model of the proximal femur derived from two-dimensional dual energy x-ray absorptiometry could be used to predict femoral strength in an experimental simulation of a fall on the greater trochanter. A set of 22 fresh cadaveric femoral specimens were scanned with use of two-dimensional dual energy x-ray absorptiometry and then were tested to failure in a materials testing system, under three-point loading, with the ground impact vector aligned within the plane and along the bisector of the femoral neck-shaft angle. Failure locations generally corresponded to stress peak locations predicted by the curved beam model. Predicted failure loads correlated well with measured failure loads for femoral neck fractures (r=0.89; percent SE of estimate=23%) and some-what less well for intertrochanteric fractures (r=0.83; percent SE of estimate=29%). Overall predictions for failure load calculated from the maximum stress peak value over both locations corresponded to measured failure loads with an r value of 0.91 (percent SE of estimate=21%). This kind of structural approach to the analysis of data for hip bone mass has the potential to provide mechanistic interpretations of the statistical associations frequently shown between conventional bone mineral measures and either hip fracture risk in vivo or bone strength in vitro.

Familial aggregation of osteoarthritis: data from the Baltimore Longitudinal Study on Aging.

OBJECTIVE: To evaluate the familial aggregation of osteoarthritis (OA) in a cohort of healthy volunteers drawn from a community setting. METHODS: Hand radiographs obtained between 1978 and 1991 and bilateral standing knee radiographs obtained between 1984 and 1991 were read for changes of OA, using Kellgren-Lawrence (K-L) scales. The hand sites were distal interphalangeal (DIP) joints, proximal interphalangeal (PIP) joints, and first carpometacarpal (CMC1) joints. For each joint group, the presence of OA in at least 1 joint in a joint group, the number of affected digits in each joint group, and the sum of the K-L grade across all joints were analyzed. Polyarticular OA was recorded if there were OA findings in 2 of 3 hand joint groups plus 1 or both knees. Data from 167 families with hand radiographs, 157 families with knee radiographs, and 148 families with both hand and knee radiographs were analyzed for sib-sib correlations. RESULTS: After adjustment for age, sex, and body mass index, clinically relevant sib-sib common correlations were found for OA of the DIP, PIP, and CMC1 joints, for OA at 2 or 3 hand sites, and for polyarticular OA (r = 0.33-0.81) when OA was defined according to the number of affected joints or as the sum of the K-L grade across all joints. CONCLUSION: These results from a cohort of volunteers drawn from a community setting and ascertained without regard to OA status demonstrate familial aggregation of OA and contribute to the evidence for heritability of OA.

The value of immediate cytologic evaluation for needle aspiration lung biopsy.

RATIONALE AND OBJECTIVES: The authors evaluate the role of immediate cytologic evaluation (ICE) with fine-needle aspiration biopsy (FNAB) for lung lesions at highest risk for pneumothorax. METHODS: A prospective randomized study was conducted of 80 patients with lung lesions surrounded by aerated parenchyma undergoing FNAB with and without ICE (47 and 33 patients, respectively). An analysis of needle passes, procedure time, complications, specimen adequacy, diagnostic yield, and accuracy of procedure was made. RESULTS: There was an increased number of needle passes with ICE (> or = three passes: 23% [11 biopsies] versus 3% [1 biopsy]; P = 0.01). Fluoroscopic procedures took longer with ICE (median time: 15 versus 9 minutes; P = 0.002) with no difference in complication rates. Specimen adequacy was similar (74% and 64%) and the procedure was diagnostic in 79% (37 biopsies) with ICE and in 70% (33 biopsies) without ICE. There were no significant differences in the sensitivity, specificity, or accuracy of the biopsy. CONCLUSIONS: Immediate cytologic evaluation improved results marginally with increased procedure time and needle passes. Immediate cytologic evaluation may be most useful for lesions at lowest risk of complications to assure that a second procedure is not required.

Observer variation in the detection of acetabular bone deficiencies.

To determine observer variation in the detection of acetabular bone deficiencies, 42 pairs of frontal (AP) and lateral hip radiographs and CT studies for total hip arthroplasty patients obtained within an average of 4 weeks of each other were reviewed separately by five radiologists and one orthopedic surgeon. Interobserver variations were calculated for each individual reading the films using kappa values. The individual film readings were then compared with a consensus reading of the CT data. When separate observers were analyzed, agreement on plain film readings was slight to fair (av. kappa = 0.1440 +/- 0.1047). The individual observers were not able to give readings which were very consistent with the CT consensus reading, resulting in a low sensitivity (65%) and specificity (74%) for acetabular defect classification with plain radiographs. The identification of acetabular bone defects from the AP and lateral views of the hip is highly subjective and variable from observer to observer.

Axial and hip bone mineral density and radiographic changes of osteoarthritis of the knee: data from the Baltimore Longitudinal Study of Aging.

OBJECTIVE: To examine the relationship between axial and hip bone mineral density (BMD) and radiographic changes of knee osteoarthritis (OA). METHODS: BMD of the lumbar spine and/or right hip was measured, using dual photon absorptiometry, in 402 men and 247 women in the Baltimore Longitudinal Study of Aging who had bilateral standing knee radiographs taken between 1984 and 1991. Radiographs were read for features of OA using Kellgren-Lawrence and reliable individual feature scales. The relationship between BMD and radiographic changes of OA was examined using multiple linear regression adjusting for age, body mass index, and smoking. Additional analyses with adjustment for menopausal status and estrogen replacement therapy were performed in a subset of women. RESULTS: Adjusted mean lumbar spine BMD was higher in subjects with knee osteophytes in both sexes: 1.23 +/- 0.02 vs 1.18 +/- 0.01 g/cm2 (p = 0.02) in men, and 1.12 +/- 0.02 vs 1.08 +/- 0.01 g/cm2 (p = 0.07) in women. There were no differences in levels of adjusted hip BMD by presence of any radiographic features of OA in either men or women. CONCLUSION: These results show that both men and women with radiographic changes of knee OA, specifically osteophytosis, have higher levels of adjusted spine but not hip BMD.

One hundred consecutive thymectomies for myasthenia gravis.

BACKGROUND: Between June 1997 and November 1993, 100 consecutive thymectomies for myasthenia gravis were performed at University of North Carolina Hospitals in Chapel Hill. METHODS: A consistent, planned protocol involving preoperative, intraoperative, and postoperative care was followed. All thymectomies were performed through a median sternotomy with removal of all visible thymus and perithymic fat in the anterior mediastinum. RESULTS: There was no perioperative mortality or longterm morbidity. Mean postoperative hospital stay was 6.3 days (range, 3 to 18 days). Ninety-six percent of the patients were extubated the day of the operation, and all patients were extubated within 24 hours. Mean postoperative intensive care unit stay was 1.2 days (range, 1 to 4 days). After a mean follow-up of 65 months (range, 1 to 199 months), 78% of all patients are improved by at least one modified Osserman classification when their current status is compared with their worst preoperative disease severity. In fact, 69% of patients with mild disease preoperatively (class I, II, or III maximal severity) are in pharmacologic remission (asymptomatic without regular medication), whereas 29% of patients with severe disease (class IV or V) are in remission (p = 0.0001). CONCLUSIONS: Our programmatic approach to thymectomy through a sternotomy has shown minimal morbidity and mortality. It is beneficial to myasthenics at both ends of the age and severity spectrum.

Case report: Phrenic artery injury--a rare complication of percutaneous needle lung biopsy.

The phrenic artery is a small vessel that is not often visualized on CT and is at risk of injury during biopsy of low lung lesions. This may result in haemoperitoneum that will not be evident on post-biopsy chest X-rays. We present a patient with a bleeding tendency who had this unusual complication following a needle aspiration lung biopsy.

Fluid-fluid levels in injured knees: do they always represent lipohemarthrosis?

PURPOSE: To determine if fluid-fluid levels on horizontal-beam radiographs of posttraumatic knee joints always represent lipohemarthrosis. MATERIALS AND METHODS: The files of 41 patients with tibial plateau fracture were reviewed retrospectively. Twelve with fluid-fluid levels on radiographs who underwent computed tomography (CT) or magnetic resonance (MR) imaging were selected; CT attenuation and MR signal intensity patterns were used to assess fluid-fluid levels. Simulated hemarthrosis and lipohemarthrosis underwent plain radiography, CT, and MR imaging. RESULTS: Eight patients showed no evidence of fat in the supernatant fluid with either CT (n = 7) or CT and MR imaging (n = 1). Fluid levels resulted from blood separating into cellular elements and supernatant serum. Four patients showed evidence of lipohemarthrosis with either CT (n = 3) or MR imaging (n = 1); in one of these patients, a double fluid-fluid level could be demonstrated retrospectively on plain radiographs. CONCLUSION: Single fluid-fluid levels in posttraumatic knee joints do not necessarily represent a lipohemarthrosis. Double fluid-fluid levels are a more specific finding.

Imaging of pelvic trauma: the role of CT with multiplanar and three-dimensional reconstruction.

Pelvic injury is a major cause of morbidity and mortality after trauma. Accurate and timely diagnosis is essential to the orthopaedic surgeon in choosing the proper management course. Traditional radiography is an important initial mode of evaluation. Computed tomography (CT) using multiplanar and three-dimensional reconstruction is a valuable complementary modality. This article reviews the role of multiplanar and three-dimensional CT imaging in the assessment of pelvic injury.

Association of hand and knee osteoarthritis: evidence for a polyarticular disease subset.

OBJECTIVE: To examine the association between hand and knee osteoarthritis (OA) in a community based population. METHODS: Radiographs of 695 participants aged > or = 40 years in the Baltimore Longitudinal Study of Aging were read for changes of OA, using Kellgren-Lawrence grade > or = 2 as the case definition. RESULTS: Logistic regression analyses, adjusting for age, gender and body mass index, revealed a significant association between OA in the knee and the following joint groups: distal and proximal interphalangeal (DIP, PIP) and Hand2 (OA in two or more hand joint groups) for grade 2-4 and grade 3-4 disease, and the first carpometacarpal (CMC1) joint for grade 3-4 disease. CONCLUSION: There is an association between OA in hand sites and the knee. The strength of the associations increases with increasing disease severity. For the PIP site, there is a trend toward increasing strength of association for increasing numbers of affected joints and bilateral disease.