What proportion of incident radiographic vertebral deformities is clinically diagnosed and vice versa?

We prospectively examined, in a large cohort of older women, the proportion of incident radiographic vertebral deformities diagnosed as incident clinical vertebral fractures in the same women at the same vertebral level. The proportion of deformities clinically diagnosed ranged from <15% for milder deformities to nearly 30% for more severe deformities.

INTRODUCTION

The relationship between radiographic and clinical vertebral fractures is incompletely understood. No previous study has prospectively compared the agreement between incident radiographic vertebral deformities and incident community-recognized, radiographically confirmed vertebral fractures in the same women at the same vertebral level(s).

MATERIALS AND METHODS

This analysis of data from the Fracture Intervention Trial included all participants who completed both baseline and at least one scheduled follow-up lateral spinal radiograph (n = 6084). Incident vertebral deformities were defined at a given vertebral level as a reduction between baseline and closeout radiographs of > or = 20% and 4 mm in any vertebral height and subdivided into two severity categories. Incident clinical vertebral fractures were those reported to clinical centers by participants and confirmed by the study radiologist, who compared the community spinal radiograph with the participant's baseline study radiograph using semiquantitative methods.

RESULTS

A total of 446 incident radiographic vertebral deformities were identified in 330 women, whereas 121 women experienced one or more confirmed incident clinical vertebral fracture. Of incident radiograpic vertebral deformities, 22.6% were also clinically diagnosed as incident vertebral fractures, with clinical diagnoses made for 28.4% of the deformities that exceeded 30% and 4 mm height loss (severe deformity) compared with 14.3% for deformities that involved > or = 20% and 4 mm but < 30% height loss (milder deformity). Of incident clinical vertebral fractures, 72.7% were morphometrically identified as incident deformities, most of them as severe deformities. More than 20% of incident clinical fractures were not identified as incident deformities by even the most liberal morphometric criterion used in this study.

CONCLUSIONS

Approximately one-fourth of incident radiographic vertebral deformities were clinically diagnosed as new vertebral fractures, although the proportion clinically diagnosed was increased for more severe deformities. Whereas most incident clinical vertebral fractures were identified as severe morphometric deformities, approximately one-fourth did not meet even the most liberal study criterion for morphometric deformity. Further study of factors that may explain the discordance between incident vertebral deformities and incident clinical vertebral fractures is important.

Towards standardization of dual X-ray absorptiometry (DXA) at the forearm: a common region of interest (ROI) improves the comparability among DXA devices

Manufacturer-implemented regions of interest (ROIs) to determine the bone mineral density (BMD) at the forearm are currently not standardized across dual X-ray absorptiometry (DXA) devices. We hypothesized that their differences introduce considerable variation in measurement results for forearm BMD when taken on different devices, and that a ROIs common to all devices with standardized placement and size significantly improve device comparability. The common ROI was defined to have a fixed length of 2 cm and to extend proximally from the location where the ulna and radius bones superimpose on the DXA image. The effects of universal standardization of forearm BMD were combined with and compared to those of the common ROI. They were drawn on 91 female study participants (ages 20-80 years, 10 per decade) who were scanned on Hologic QDR-4500, Aloka DCS-600EX, GE Lunar PIXI and Norland pDEXA DXA scanners. For all device combinations, manufacturer-implemented ROI root mean-square errors were significantly higher than for the common ROI, suggesting that implementing an ROI with common design on all scanners is a good way to reduce interdevice variability. When manufacturer-implemented ROIs were universally standardized root mean-square error (RMSE) values were less different from that of the nonstandardized Common ROI, suggesting that universal standardization can further improve interdevice comparability even when a common ROI such as the one implemented here is used. ROI standardization dramatically improves interdevice comparability.

Effect of spinal degenerative changes on volumetric bone mineral density of the central skeleton as measured by quantitative computed tomography

PURPOSE

To evaluate the impact of degenerative changes due to osteoarthritis (OA) at the spine on volumetric bone mineral density (BMD) as measured by volumetric quantitative computed tomography (vQCT).

MATERIAL AND METHODS

Eighty-four elderly women (mean age 73 +/- 6 years), comprising 33 with vertebral fractures assessed by radiographs and 51 without vertebral fractures, were studied. Trabecular, cortical, and integral BMD were examined at the spine and hip using a helical CT scanner and were compared to dual X-ray absorptiometry (DXA) measurements at the same sites. OA changes visible on the radiographs were categorized into two grades according to severity. Differences in BMD measures obtained in the two groups of patients defined by OA grade using the described radiologic methods were compared using analysis of variance. Standardized difference (effect sizes) was also compared between radiologic methods.

RESULTS

Spinal trabecular BMD did not differ significantly between OA grade 0 and OA grade 1. Spinal cortical and integral BMD measures showed statistically significant differences, as did the lumbar spine DXA BMD measurement (13%, P = 0.02). The QCT measurements at the hip were also higher in OA 1 subjects. Femoral trabecular BMD was 13-15% higher in OA grade 1 subjects than in OA grade 0 subjects. The cortical BMD measures in the CT_TOT_FEM and CT_TROCH ROI's were also higher in the OA 1 subjects. The integral QCT BMD measures in the hip showed difference between grades OA 1 and 0. The DXA measurements in the neck and trochanter ROI's showed smaller differences (9 and 11%, respectively). There were no statistically significant differences in bone size.

CONCLUSION

There is no evidence supporting that trabecular BMD measurements by QCT are influenced by OA. Instead, degenerative changes have an effect on both cortical and integral QCT, and on DXA at the lumbar spine and the hip. For subjects with established OA, assessment of BMD by volumetric QCT may be suggested.

MR imaging of post-traumatic articular cartilage injuries confined to the femoral trochlea. Arthroscopic correlation and clinical significance

OBJECTIVE

To assess and describe post-traumatic articular cartilage injuries isolated to the trochlear groove and provide insight into potential mechanism of injury.

MATERIALS AND METHODS

We retrospectively evaluated MR imaging findings of all knee MRIs performed at our institution over the last 2 years (2450). Thirty patients met the criteria of a cartilage injury confined to the trochlear groove. In 15 cases, which were included in our study, arthroscopic correlation was available. Each plane was evaluated and graded for the presence and appearance of articular cartilage defects using a standard arthroscopic grading scheme adapted to MR imaging. Any additional pathological derangement was documented and information about the mechanism of injury was retrieved by chart review.

RESULTS

In all cases the cartilaginous injury was well demonstrated on MRI. In 13 patients additional pathological findings could be observed. The most frequently associated injury was a meniscal tear in nine patients. In eight cases, the arthroscopic grading of the trochlear injury matched exactly with the MRI findings. In the remaining seven cases, the discrepancy between MRI and arthroscopy was never higher than one grade. In 13 out of 15 of patients trauma mechanism could be evaluated. Twelve patients suffered an indirect twisting injury and one suffered a direct trauma to their knee.

CONCLUSION

The findings of this study demonstrate that MR imaging allows reliable grading of isolated injury to the trochlear groove cartilage and assists in directing surgical diagnosis and treatment. These injuries may be the only hyaline cartilage injury in the knee and meniscal tears are a frequently associated finding. Therefore, it is important to search specifically for cartilage injuries of the trochlear groove in patients with anterior knee pain, even if other coexistent pathology could potentially explain the patient's symptoms.

Micro-CT Arthrography: A Pilot Study for the Ex Vivo Visualization of the Rat Knee Joint

OBJECTIVE

In our study, we evaluated the potential of micro-CT for the assessment of the rat knee joint using ex vivo micro-CT arthrography. The aims of the study were to introduce the technique of micro-CT arthrography and to visualize the normal anatomy of the rat knee. The secondary aims were the quantification of retropatellar cartilage thickness and the analysis of microstructural cancellous bone parameters within the tibial epiphysis.

CONCLUSION

Micro-CT arthrography is a novel technique for the indirect visualization of the distinct features and structural analysis of the rat knee joint. This technique represents an additional imaging and analysis tool in small-animal research.

Teriparatide reduces the fracture risk associated with increasing number and severity of osteoporotic fractures

The relationship between prior fractures and risk of new fractures was evaluated in 931 postmenopausal women with prevalent vertebral fractures randomized to daily placebo or teriparatide (20 mug) in the Fracture Prevention Trial. The median observation time was 21 months. Among placebo patients with one, two, or three or more prevalent vertebral fractures, 7%, 16%, and 23%, respectively, developed vertebral fractures (by Cochran-Armitage trend test, P < 0.001), and 3%, 9%, and 17% developed moderate or severe vertebral fractures (P < 0.001). Among placebo patients with mild, moderate, or severe prevalent vertebral fractures, 10%, 13%, and 28%, respectively, developed vertebral fractures (P < 0.001), and 4%, 8%, and 23% developed moderate or severe vertebral fractures (P < 0.001). Among placebo patients with zero, one, or two or more prior nonvertebral fragility fractures, 4%, 8%, and 18%, respectively, developed nonvertebral fragility fractures (P < 0.001). In the teriparatide-treated group, there was no significant increase in vertebral or nonvertebral fracture risk in these subgroups. In summary, the number and severity of prevalent vertebral fractures independently predicted the risk for new vertebral fractures, and the number of prior nonvertebral fractures predicted the risk for new nonvertebral fractures in placebo patients. However, in teriparatide-treated patients, the increased fracture risk associated with prior number and severity of fracture was not observed.

Association of severe vertebral fractures with reduced quality of life: reduction in the incidence of severe vertebral fractures by teriparatide

OBJECTIVE

The association between vertebral fracture severity and health-related quality of life (HRQOL) was investigated in a subset of patients in the Fracture Prevention Trial. We sought to determine whether vertebral fracture severity was associated with HRQOL scores, and if so, to determine the effects of teriparatide (recombinant human parathyroid hormone 1-34) on vertebral fracture grades that most strongly impact HRQOL in postmenopausal women with osteoporosis.

METHODS

Vertebral fracture severity was assessed by the visual semiquantitative (SQ) method. A subset of 444 patients with a baseline radiograph completed the Osteoporosis Assessment Questionnaire. Baseline HRQOL scores were modeled as a function of maximum baseline vertebral fracture grade, while controlling for age, bone mineral density, body mass index, and back pain.

RESULTS

The effect of baseline vertebral fracture grade on baseline HRQOL was statistically significant, while interactions between vertebral fracture grade and the other variables were not statistically significant. SQ grade 3 (SQ3) vertebral fractures were associated with a significantly lower overall HRQOL score and with significantly lower physical function, symptoms, and emotional status dimension scores. After a median of 19 months of therapy, new or worsening SQ3 vertebral fractures occurred in 21 of 448 patients (4.7%) in the placebo group compared with 3 of 444 patients (0.7%) in the 20 mug/day teriparatide group. The risk of developing a new or worsened SQ3 vertebral fracture was reduced by 86% (P < 0.001) in patients treated with 20 mug/day teriparatide.

CONCLUSION

Compared with prevalent fractures of lesser severity, SQ3 vertebral fractures were associated with reduced HRQOL. Teriparatide treatment significantly reduced the risk of new or worsening SQ3 vertebral fractures. These findings suggest, but do not directly demonstrate, a benefit of teriparatide on HRQOL.

Short tau inversion recovery and proton density-weighted fat suppressed sequences for the evaluation of osteoarthritis of the knee with a 1.0 T dedicated extremity MRI: development of a time-efficient sequence protocol

Aim of this study was to develop a time-efficient sequence protocol for a 1.0 T dedicated MR system to be used for whole-organ scoring of osteoarthritis (OA). Thirty-four knees were examined using a protocol that included fat suppressed fast spin echo proton density weighted sequences (PDFS) in three planes plus a coronal STIR sequence. Two radiologists scored each knee by consensus for five OA features. In separate sessions, all knees were scored using three different combinations of sequences: (1) all four sequences (reference protocol, 16 min 31 s scanning time), (2) three PDFS sequences without STIR ("No STIR", 12 min 25 s scanning time) and (3) sagittal and axial PDFS sequences plus a coronal STIR sequence ("No PDFS", 11 min 49 s scanning time). Agreement of the readings using both subsets of sequences compared to the reference protocol was evaluated using weighted kappa statistics. kappa-coefficients showed good or excellent agreement for both sequence subsets in comparison to the reference protocol for all assessed features. kappa-coefficients for No PDFS/No STIR: bone marrow abnormalities (0.74/0.67), subarticular cysts (0.84/0.63), marginal osteophytes (0.77/0.71), menisci (0.75/0.79), tibial cartilage (0.71/0.78). Optimization of sequence protocols consisting of three sequences results in time savings and cost efficiency in imaging of knee OA without loss of information over a more time consuming protocol.

Femoral neck trabecular microstructure in ovariectomized ewes treated with calcitonin: MRI microscopic evaluation

Ovariectomy induces deterioration of the trabecular structure in the femoral neck of ewes, as depicted by MR microscopic imaging. This structural deterioration is prevented by salmon calcitonin treatment.

INTRODUCTION

This study evaluated the trabecular (Tb) microarchitecture of an ovariectomy (OVX)-induced osteoporotic model in ewes and determined the effects of salmon calcitonin (sCT), an osteoclast inhibitor, on the Tb structure. This is the first report of OVX-induced changes in the Tb structure in the femoral neck in the ewes and effect of sCT on the microarchitecture.

MATERIALS AND METHODS

Ewes (5-8 years old, n = 28) were equally allocated into sham (Sham), OVX injected with vehicle, or OVX injected with sCT at 50 or 100 IU, three injections per week. They were killed 6 months after OVX. The femoral neck was examined with an MR imager at 9.4 T in axial, coronal, and sagittal planes. An internal calibration procedure as a means of standardizing image analysis was used to adjust the segmentation threshold. Data from all three planes were averaged.

RESULTS AND CONCLUSIONS

Compared with Sham, OVX induced significant changes (p < 0.0125) in the MRI-derived femoral neck Tb structure: Tb bone volume fraction (BV/TV), -18%; Tb number, -20%; Tb separation, +23%; number of free ends, +28%; number of nodes, -39%; number of Tb branches, -23%; mean length of Tb branches, -19%. Compared with OVX, treatment of sCT at 100 IU significantly improved all the Tb structural parameters to the Sham level (p < 0.0001 approximately p = 0.0281), whereas 50 IU significantly increased the Tb number and the mean length of the Tb branches. BV/TV explained 74% of the variation of compressive stress of the trabecular cylinder cores of the femoral neck. Combining all structural parameters in a multivariate regression analysis significantly improved the explanation to 84%, and adding BMD further improved the predictive ability of the model to 92%. We conclude that OVX induces deterioration of the MRI-derived Tb microstructure in the femoral neck of ewes. sCT treatment prevents OVX-induced changes. The femoral neck microarchitecture significantly correlates with its biomechanical properties. Combining microstructural parameters with BMD further improves the prediction of bone biomechanical properties. The effects of sCT on OVX ewes may help explain reduced fracture risk in postmenopausal osteoporotic women treated with sCT.

Risk factors for a first-incident radiographic vertebral fracture in women > or = 65 years of age: the study of osteoporotic fractures

Vertebral fractures in older women signal an increased risk of additional osteoporotic fractures. To identify risk factors for first vertebral fractures, we studied 5822 women > or =65 years of age who had no fracture on baseline radiographs of the spine. Several modifiable risk factors increased an older woman's risk of developing a first vertebral fracture, and women with multiple risk factors and low BMD had the highest risk. Risk factors and low BMD should be useful to help focus efforts to prevent these fractures.

INTRODUCTION

Vertebral fractures are a common cause of back pain and disability and signal an increased risk of additional osteoporotic fractures in older women. Little is known about the risk factors for the first occurrence of a vertebral fracture.

MATERIALS AND METHODS

To identify risk factors for a first vertebral fracture, we studied 5822 women > or =65 years of age from the Study of Osteoporotic Fractures who had no fracture on baseline radiographs of the spine. We measured potential risk factors and BMD of the wrist and calcaneus at baseline and BMD of the spine and hip halfway through follow-up. Fractures were assessed by standard methods from spine radiographs obtained at baseline and follow-up an average of 3.7 years later.

RESULTS AND CONCLUSIONS

In multivariable analyses, older age, previous nonspine fracture, low BMD at all sites, a low body mass index (BMI), current smoking, low milk consumption during pregnancy, low levels of daily physical activity, having a fall, and regular use of aluminum-containing antacids independently increased the risk of a first vertebral fracture. Women using estrogen and those who engaged in recreational physical activity had a decreased risk. The effects of low BMI, smoking, use of estrogen and antacids, and previous fracture were partially mediated by BMD. Women in the lower third of wrist BMD with five or more risk factors had a 12-fold greater risk than women in the highest third of BMD who had zero to three risk factors. The 27% of women at highest risk suffered 60% of the incident fractures. In conclusion, several modifiable risk factors and BMD independently increase an older woman's risk of developing a first vertebral fracture. The combination of risk factors and BMD should be useful for focusing efforts to prevent vertebral fractures.

Application of micro-CT assessment of 3-D bone microstructure in preclinical and clinical studies

As the mechanical competence of trabecular bone is a function of its apparent density and 3-D distribution, assessment of 3-D trabecular structural characteristics may improve our ability to understand the pathophysiology of osteoporosis, to test the efficacy of pharmaceutical intervention, and to estimate bone biomechanical properties. We have studied ovariectomy-induced osteopenia in rats and its treatment with agents such as estrogen and sodium fluoride. We have demonstrated that 3-D micro-computed tomography (microCT) can directly quantify mouse trabecular and cortical bone structure with an isotropic resolution of 6 microm(3). MicroCT is also useful for studying osteoporosis in mice and phenotypes of mice with gene manipulation, such as SHIP-knockout mice, which are severely osteoporotic due to increased numbers of hyperresorptive osteoclasts, PTHrP heterozygous-null mice, and mice with Zmpste24 deficiency. MicroCT can quantify osteogenesis in mouse Ilizarov leg-lengthening procedures, osteoconduction in a rat cranial defect model, and structural changes in arthritic rabbits, rats, and mice. In clinical studies, we evaluated longitudinal changes in the iliac crests. Paired bone biopsies from the same premenopausal and postmenopausal women showed the changes in 3-D trabecular structure, such as decreased trabecular thickness, shifting of trabecular model from platelike structure to rodlike structure, and decreased degree of anisotropy were remarkable. Treatment with PTH in postmenopausal women with osteoporosis significantly improved trabecular morphology with a shift toward a more platelike structure, increased trabecular connectivity density, and increased cortical thickness. Paired bone biopsy specimens from the iliac crest in postmenopausal women with osteoporosis before and an average of 2 years after beginning of estrogen replacement therapy demonstrated that posttreatment biopsies showed a significant change in the ratio of plates to rods and statistically insignificant changes in other 3-D trabecular parameters. Thus, microCT can characterize 3-D structure of various animal models, and the longitudinal changes in 3-D bone microarchitectural integrity that deteriorates in the transmenopausal period, is preserved with HRT, and is improved with PTH treatment in postmenopausal women.

Treatment with raloxifene for 2 years increases vertebral bone mineral density as measured by volumetric quantitative computed tomography

Volumetric quantitative computed tomography (vQCT), using multiple thin-slice acquisition, measures three-dimensional volumetric bone mineral density (BMD, mg/cm3). vQCT is often used to measure BMD of lumbar vertebrae and may detect early changes in trabecular, cortical, or integral BMD that extend beyond the technical limits of areal dual X-ray absorptiometry (DXA) BMD measurements. The objective of this study was to determine the effect of 2 years of raloxifene (RLX) treatment on several volumetric BMD measures in a subset of postmenopausal women (n=58) enrolled in the Multiple Outcomes of Raloxifene Evaluation (MORE) trial. Patients in this study were randomized to one of three treatment groups: placebo (n=21), RLX 60 mg/day (n=17), or RLX 120 mg/day (n=20), and all patients received daily calcium (500 mg) and vitamin D (400-600 IU) supplementation. Data from the raloxifene treatment groups were pooled for each analysis. Following 2 years of raloxifene treatment, there was a significant percent change from baseline in the vQCT regions of interest (ROIs) of midintegral BMD, total trabecular BMD, and total integral BMD (P<0.05) compared to placebo, while there was no significant change in the spinal DXA BMD measurement. These data provide the first longitudinal assessment by vQCT of changes in vertebral bone density after 2 years of treatment with raloxifene. vQCT appears to be a valuable technique for measuring the effects of raloxifene treatment in this population of postmenopausal women with osteoporosis.

Effects of anakinra monotherapy on joint damage in patients with rheumatoid arthritis. Extension of a 24-week randomized, placebo-controlled trial

OBJECTIVE

To determine the effects of treatment on the radiologic manifestations of joint damage in patients with rheumatoid arthritis (RA) who participated in a 24-week extension study of a randomized, placebo-controlled clinical trial of anakinra, a recombinant human interleukin 1 receptor antagonist.

METHODS

The patients had entered a 24-week, randomized, double-blind, placebo-controlled study. Anakinra was self-administered by subcutaneous injection of 30, 75, or 150 mg/day. Upon completion of the placebo-controlled phase, the patients entering the extension study who had received placebo were randomized to one of the 3 treatment dosages for a further 24 weeks, and the patients who had been initially randomized to one of the 3 anakinra dosages continued to receive the same dosage. Radiographs of the hands were obtained at baseline and at 24 and 48 weeks. The radiographs were evaluated using a modified Sharp method.

RESULTS

A total of 472 patients were recruited. The mean change in the total modified Sharp score of 178 patients who completed 48 weeks treatment, including all dosages, was significantly less than the change observed in 58 patients who received placebo for 24 weeks and anakinra for 24 weeks (p = 0.015). A significant reduction in the change of the total modified Sharp score was observed in the patients who received anakinra 75 and 150 mg/day. The total modified Sharp score was reduced significantly more during the second 24-week treatment period, compared to the first (p < 0.001). Significant reductions in the second 24-week period were observed following anakinra 75 mg/day (p = 0.006) and 150 mg/day (p = 0.008).

CONCLUSION

Patients with RA who received anakinra for 48 weeks demonstrated significant slowing of radiographic joint damage. The treatment effect observed after the first 24-week period appeared to increase when anakinra was continued for 48 weeks.

Multispectral analysis of bone lesions in the hands of patients with rheumatoid arthritis

Quantitative measures of rheumatoid arthritis (RA) disease progression can provide valuable tools for evaluation of new treatments during clinical trials. In this study, a novel multispectral (MS) MRI analysis method is presented to quantify changes in bone lesion volume (DeltaBLV) in the hands of RA patients. Image registration and MS analysis were employed to identify MS tissue class transitions between two serial MRI exams. DeltaBLV was determined from MS class transitions between two time points. The following three classifiers were investigated: (a) multivariate Gaussian (MVG), (b) k-nearest neighbor (k-NN), and (c) K-means (KM). Unlike supervised classifiers (MVG, k-NN), KM, an unsupervised classifier, does not require labeled training data, resulting in potentially greater clinical utility. All MS estimates of DeltaBLV were linearly correlated (r(p)) with manual estimates. KM and k-NN estimates also exhibited a significant rank-order correlation (r(s)) with manual estimates. For KM, r(p) = 0.94 p < 0.0001, r(s) = 0.76 p = 0.002; for k-NN, r(p) = 0.86 p = 0.0001, r(s) = 0.69 p = 0.009; and for MVG, r(p) = 0.84 p = 0.0003, r(s) = 0.49 p = 0.09. Temporal classification rates were as follows: for KM, 90.1%; for MVG, 89.5%; and for k-NN, 86.7%. KM matched the performance of k-NN, offering strong potential for use in multicenter clinical trials. This study demonstrates that MS tissue class transitions provide a quantitative measure of DeltaBLV.

Use of the modified three-point Dixon technique in obtaining T1-weighted contrast-enhanced fat-saturated images on an open magnet

The purpose of this study was to investigate the modified three-point Dixon technique as a method for obtaining fat-saturated T1-weighted sequences before and after intravenous gadolinium administration using an open MR imaging scanner. A preliminary experiment using an oil/gadolinium phantom was performed on a 0.35-T open magnet and an advanced 1.5-T unit. Fat saturation was achieved at 1.5 T using a frequency selective presaturation technique and a modified three-point Dixon technique on the low-field scanner. The modified three-point Dixon sequence was then evaluated in ten patients undergoing MRI examinations of the spine with gadolinium enhancement to determine image characteristics and diagnostic potential. The phantom study demonstrated a homogenous suppression of signal from oil and a good distinction between fat and a gadolinium chelate on the 0.35-T unit comparable to that on the 1.5-T scanner. By applying the modified three-point Dixon technique on the open-magnet, the distinction between fat and gadolinium dimeglumine was rated as very good in 139 and good in 17 axial slices in a total of 156 images. No image was rated as difficult or not possible. Motion artifacts that hampered the reading were detected in the lower cervical spine due to respiratory movement in four (3% of all) images. The modified three-point Dixon technique provides the combination of gadolinium enhancement with fat saturation on an open magnet. Early clinical applications appear promising.

Use of multispectral magnetic resonance imaging analysis to quantify erosive changes in the hands of patients with rheumatoid arthritis: short-term and long-term longitudinal studies

OBJECTIVE

Magnetic resonance imaging (MRI) has been shown to be more sensitive than radiography for detecting bone erosions in rheumatoid arthritis (RA). Semiquantitative scoring based on visual image assessment has been introduced. However, there is considerable interest in true quantitative measures, particularly in the context of clinical trials designed to show differences between treatment groups. This study was undertaken to investigate the use of a new quantitative approach, multispectral (MS) image analysis, for assessing erosive change.

METHODS

T1-weighted spin-echo (SE) and fat-suppressed gradient-echo (GE) sequences of metacarpophalangeal joints of the dominant hand were acquired at various time points throughout a 2-year period. MS analysis was applied to all images, resulting in segmentation into a generalized bone and a soft tissue class. Voxel changes from one to the other class identified apparent bone lesion volume change (Delta BLV). MR images were also visually scored for erosions (E score). All analyses were performed separately, on a per-joint basis, for short-term and long-term data sets.

RESULTS

Analysis of variance with adjustment for individual effect revealed similar results in the short-term and the long-term studies, using either GE or SE images for visual assessment. Patients with an increase in E score on visual assessment had a significantly higher Delta BLV than those without.

CONCLUSION

Temporal MS analysis of MRIs can be used to detect and quantify erosive changes in RA. This semiautomated method may be useful for demonstrating differences between treatment groups in clinical trials.

Imaging in spondyloarthropathies

Seronegative spondyloarthropathies comprise a group of inflammatory arthritides, which consists of ankylosing spondylitis, psoriatic arthritis, reactive arthritis (Reiter's syndrome), enteropathic arthritis, and undifferentiated spondyloarthropathy. All of them share common laboratory, clinical, and imaging findings, with characteristic involvement of the sacroiliac joints, spine, and, to various degrees, peripheral joints. For many years, conventional radiography was the mainstay for definitive diagnosis of sacroiliitis and for follow-up of the anatomic changes in the spine, peripheral joints, and entheses. Conventional radiographs remain the imaging investigation of choice; however, they are unable to detect early inflammatory changes of sacroiliitis, which are important for establishing a diagnosis without delay. Other imaging modalities, such as computed tomography, bone scintigraphy, magnetic resonance imaging, and ultrasonography have improved the capabilities of detecting early disease and became useful adjuncts to plain films. In addition, they also have enabled more accurate detection of pathology at various anatomic sites of the musculoskeletal system predominantly involved in spondyloarthropathies. This article will review and highlight the role of each of these modalities in the assessment of the axial and peripheral skeleton in seronegative spondyloarthropathies.

Rheumatoid Arthritis of the Hand and Wrist:Comparison of Three Imaging Techniques

OBJECTIVE

The purpose of this study was to compare the relative results from conventional high-field-strength 1.5-T MRI, 0.2-T low-field-strength dedicated extremity MRI, and radiography to detect and grade bone erosions, joint-space narrowing, and synovitis in the hands and wrists of patients with rheumatoid arthritis.

SUBJECTS AND METHODS

Eighteen patients with rheumatoid arthritis underwent conventional high-field-strength MRI, low-field-strength dedicated extremity MRI, and conventional radiography of both hands and wrists. Two independent reviewers searched for the presence and extent of bone erosions, joint-space narrowing, and synovitis. Bone erosions (E scores) and joint-space narrowing (J scores) were evaluated at 14 and 13 sites, respectively, on conventional high-field-strength MRI, low-field-strength dedicated extremity MRI, and radiography, using the Sharp-Genant scoring system. Synovitis (S scores) were evaluated at 13 sites on conventional high-field-strength MRI and low-field-strength dedicated extremity MRI.

RESULTS

For the detection of bone erosions, we found no significant difference (p = 0.71) between conventional high-field-strength MRI (mean +/- SD E score, 27.5 +/- 9.8) and low-field-strength dedicated extremity MRI (28.8 +/- 10.0), but a significant difference (p < 0.001) appeared between MRI and radiography (13.1 +/- 8.3). J scores derived from MRI (conventional high-field-strength MRI, 15.2 +/- 8.3; low-field-strength dedicated extremity MRI, 14.5 +/- 10.4) were higher than those derived from radiography (12.7 +/- 9.6), although the difference was not significant (p = 0.70). Conventional high-field-strength MRI (S score, 35.1 +/- 8.6) and low-field-strength dedicated extremity MRI (30.8 +/- 10.2) were equivalent (p = 0.14) for the evaluation of synovitis. The interobserver agreement for MRI scores was good to excellent (intraclass correlation coefficients, 0.83-0.94).

CONCLUSION

Conventional high-field-strength MRI and low-field-strength dedicated extremity MRI showed similar results in terms of cross-sectional grading of bone erosions, joint-space narrowing, and synovitis in the hands and wrists of patients with rheumatoid arthritis.

Quantitative and qualitative assessment of closed fracture healing using computed tomography and conventional radiography

RATIONALE AND OBJECTIVES

Development of new agents to induce fracture healing requires more sensitive methods to detect early changes in fracture repair. The aims of this study were to determine quantitative and qualitative features of fracture healing using volumetric computed tomography (CT) and to compare them with conventional radiography during the weeks following uncomplicated fractures of the appendicular skeleton.

MATERIALS AND METHODS

39 otherwise healthy men and women with acute, closed fractures of the distal radius, tibial and/or fibular malleoli, or tibial shaft, were enrolled and underwent CT and X-ray imaging at 1, 2, 4, 8, 12, and 16 (tibial shaft only) weeks post fracture. Qualitative assessment included fracture line/margins, fracture gap, external callus appearance, callus-to-cortex ratio, bridging, and radiologic union. Quantitative assessment of CT density changes (Hounsfield units [HU]) in the fracture gap was performed in a subset of 8 fracture patients using MEDx multimodality image analysis software (Sterling,VA). The analysis was performed by drawing free form regions of interest (ROI) covering the fracture gap on baseline (week 1) images and by automated registration of the follow-up images to the baseline co-ordinate system.

RESULTS

The mean time to achieve radiologic union on CT was slightly shorter than on X-rays for radial and tibial shaft fractures (7.3 vs. 8.0 weeks, P = .1). Blurring of the fracture margins and reactive sclerosis were the earliest signs of healing in both modalities. External callus formation was evident in 11 cases and was detected earlier with CT technique. Overall, CT images allowed for more complete and detailed visualization of healing compared with conventional X-rays, which were limited by cast and fixation hardware superimposition, especially in subjects with malleolar and distal radial fractures. Quantitative evaluation showed good intraobserver and interobserver reproducibility and a statistically significant correlation to qualitative changes.

CONCLUSION

Our methods of fracture healing assessment are reliable tools that are able to detect early changes in normal bone healing and may serve as useful additions to subjective image analysis in monitoring fracture healing in clinical trials. CT shows some advantages over conventional X-rays in evaluation of early fracture healing.

Measurement of changes in trabecular bone at fracture sites using X-ray CT and automated image registration and processing

Currently, there are no in vivo techniques for quantifying healing within fractures involving mainly trabecular bone. Methods for quantitatively assessing healing would aid the investigation of new treatment regimes, and might also be useful for predicting whether a patient may be undergoing delayed union. Using CT and automated image registration, we have developed an image processing technique for measuring changes in CT image intensity at fracture sites. The technique focuses on quantifying the formation of new mineralised tissue within fracture gaps, while ignoring loss of bone mineral due to disuse osteoporosis. Seven patients with fractures of the distal radius were examined for 12 weeks following fracture. To assess reproducibility of measurements of change in CT intensity at the fracture line, measurements were performed on two separate occasions, by each of two independent readers. Reproducibility was compared to rates of change over time, to determine detectable differences in individual progression. Scans were scored qualitatively for features of healing and scores compared to the quantitative measurements. The mean (SD) change in CT intensity was +128 (65) Hounsfield Units (HU) over the 12 week follow-up. Inter- and intra-observer reproducibilities were both similar (+/- 17 HU), 1/7 of the change seen during the study. In this small patient cohort, a significant increase in CT intensity was seen 2 weeks post-fracture. Large early increases in CT intensity were associated with early visual appearance of sclerosis and blurring of the fracture line. In this preliminary, prospective study, we have developed a reproducible quantitative technique for measuring changes in CT intensity of trabecular bone at the fracture line in the distal radius. Further work is required to determine whether it can be used to identify, or monitor patients who are undergoing delayed fracture repair. The technique appears sensitive for measuring changes immediately post-fracture, and could have a role in examining potential effects of new therapies in patient cohorts.

Patient retention and hand-wrist radiograph progression of rheumatoid arthritis during a 3-year prospective study that prohibited disease modifying antirheumatic drugs

OBJECTIVE

To quantitate patient retention and radiographic progression rates in serial hand/wrist radiographs of patients with rheumatoid arthritis (RA) who were not being treated with disease modifying antirheumatic drugs (DMARD).

METHODS

A total of 1433 RA patients with 1-7 years' disease duration entered a 3-year prospective randomized double-blind clinical trial comparing the nonsteroidal antiinflammatory drugs (NSAID) etodolac (300 or 1000 mg daily) and ibuprofen (2400 mg daily). Standardized hand/wrist radiographs were obtained yearly and at dropout if > 6 months after entry. DMARD were not permitted. Joint erosion, joint space narrowing (JSN), and total scores of 3 readers were averaged.

RESULTS

At entry, mean duration of RA was 3.5 years (range 1-7); ages were 21-78 years; patients were 71% female, 84% Caucasian, 67% rheumatoid factor (RF) positive; tender joint count was 29, swollen joint count 22, Westergren erythrocyte sedimentation rate (ESR) 49, and C-reactive protein (CRP) 2.44. There were 824 (57.5%) patients who completed >or= 6 months and had paired radiographs; 46% completed 48 weeks; 31%, 98 weeks; and 19%, 147 weeks. Months between paired radiographs (time in study) averaged 23.1 (range 6-36). Mean progression rates for total, erosion, and JSN scores (5.08, 2.53, and 2.54 units per year, respectively) were significantly associated with time in study, baseline RF, ESR, CRP, swollen joint count, presence of erosions at entry, and with 20% and 50% composite clinical responses. Painful joint count and RA duration were weakly associated only with progression of erosions. Progression rates were not associated with age, sex, corticosteroid use, or prior DMARD use. Patients who completed the 3-year trial had less severe disease activity and radiographic progression than those who dropped out.

CONCLUSION

In this 3-year prospective double-blind clinical trial that prohibited DMARD, retention rates (57.5%, 46%, 31%, and 19% at 0.5, 1, 2, and 3 years) were similar to those in the non-DMARD-treated placebo groups of recent published studies. Radiographic progression rates are reported for 824 non-DMARD-treated patients during RA of 1-10 years' duration. This information may be useful as background information in the interpretation of longterm clinical trials that evaluate joint radiographic outcomes.

Whole-Organ Magnetic Resonance Imaging Score (WORMS) of the knee in osteoarthritis

OBJECTIVES

To describe a semi-quantitative scoring method for multi-feature, whole-organ evaluation of the knee in osteoarthritis (OA) based on magnetic resonance imaging (MRI) findings. To determine the inter-observer agreement of this scoring method. To examine associations among the features included in the scoring method.

METHODS

Nineteen knees of 19 patients with knee OA were imaged with MRI using conventional pulse sequences and a clinical 1.5 T MRI system. Images were independently analyzed by two musculoskeletal radiologists using a whole-organ MRI scoring method (WORMS) that incorporated 14 features: articular cartilage integrity, subarticular bone marrow abnormality, subarticular cysts, subarticular bone attrition, marginal osteophytes, medial and lateral meniscal integrity, anterior and posterior cruciate ligament integrity, medial and lateral collateral ligament integrity, synovitis/effusion, intraarticular loose bodies, and periarticular cysts/bursitis. Intraclass correlation coefficients (ICC) were determined for each feature as a measure of inter-observer agreement. Associations among the scores for different features were expressed as Spearman Rho.

RESULTS

All knees showed structural abnormalities with MRI. Cartilage loss and osteophytes were the most prevalent features (98% and 92%, respectively). One of the least common features was ligament abnormality (8%). Inter-observer agreement for WORMS scores was high (most ICC values were >0.80). The individual features showed strong inter-associations.

CONCLUSION

The WORMS method described in this report provides multi-feature, whole-organ assessment of the knee in OA using conventional MR images, and shows high inter-observer agreement among trained readers. This method may be useful in epidemiological studies and clinical trials of OA.

The effects of strontium ranelate on the risk of vertebral fracture in women with postmenopausal osteoporosis

BACKGROUND

Osteoporotic structural damage and bone fragility result from reduced bone formation and increased bone resorption. In a phase 2 clinical trial, strontium ranelate, an orally active drug that dissociates bone remodeling by increasing bone formation and decreasing bone resorption, has been shown to reduce the risk of vertebral fractures and to increase bone mineral density.

METHODS

To evaluate the efficacy of strontium ranelate in preventing vertebral fractures in a phase 3 trial, we randomly assigned 1649 postmenopausal women with osteoporosis (low bone mineral density) and at least one vertebral fracture to receive 2 g of oral strontium ranelate per day or placebo for three years. We gave calcium and vitamin D supplements to both groups before and during the study. Vertebral radiographs were obtained annually, and measurements of bone mineral density were performed every six months.

RESULTS

New vertebral fractures occurred in fewer patients in the strontium ranelate group than in the placebo group, with a risk reduction of 49 percent in the first year of treatment and 41 percent during the three-year study period (relative risk, 0.59; 95 percent confidence interval, 0.48 to 0.73). Strontium ranelate increased bone mineral density at month 36 by 14.4 percent at the lumbar spine and 8.3 percent at the femoral neck (P<0.001 for both comparisons). There were no significant differences between the groups in the incidence of serious adverse events.

CONCLUSIONS

Treatment of postmenopausal osteoporosis with strontium ranelate leads to early and sustained reductions in the risk of vertebral fractures.

Two new regions of interest to evaluate separately cortical and trabecular BMD in the proximal femur using DXA

To differentiate changes in trabecular and cortical bone density at a skeletal site bearing body weight, the main goal of this retrospective study was to develop and characterize two new regions of interest (ROIs) for DXA at the hip, one mainly focusing on trabecular bone and another mainly focusing on cortical bone. Specific aims were to maximize the precision of the ROIs and to characterize their usefulness for monitoring age-related bone loss and discriminating controls from fracture cases in a cross-sectional study population and to compare them with earlier ROIs designed by our group. The study used populations from two different previous studies conducted in our laboratory, with one comprising cohorts of healthy premenopausal women, healthy postmenopausal women, and postmenopausal osteoporotic women with at least one spinal fracture (Spine Fx Study) and the other one comprising two cohorts of age-matched postmenopausal women, in whom cases had sustained a hip fracture (Hip Fx study). The new ROI for trabecular bone (CIRCROI) tries to improve on the earlier custom-designed Central ROI, which was also targeted at trabecular bone. CIRCROI consists of an approximate largest circle that can fit inside the femoral proximal metaphysis without touching the superior and inferior endocortical walls. The new ROI for cortical bone (CORTROI) at a site bearing body weight is defined as a horizontal rectangular box crossing the femoral shaft below the lesser trochanter. CORTROI BMD cohort means were significantly higher than all other ROIs, and CIRCROI BMD cohort means were lower than standard ROIs with the exception of Ward's ROI. CIRCROI BMD was highly correlated with total femur BMD ( r=0.94) and Central BMD ( r=0.93), whereas CORTROI BMD correlations were lower (highest with total femur BMD ( r=0.86)). Fracture discrimination odds ratios (ORs) of all ROIs were significant for the Hip Fx Study, with CIRCROI BMD having the highest, and CORTROI BMD the lowest, OR (4.83 and 2.49 per SD, respectively, compared with 3.69 for Ward's ROI as the highest OR of standard ROIs). For the Spine Fx Study, only spinal and trochanteric BMD had significant OR. The new trabecular ROI had good short-term precision, comparable to the standard ROIs at the hip, but improving on that of Ward's triangle, the only standard ROI only including the anterior and posterior cortical walls and therefore more predominantly consisting of trabecular bone than other standard ROIs. The precision of the new cortical ROI was lower than standard DXA ROIs, except for Ward's triangle, but provides unique information on purely cortical bone at a skeletal site bearing body weight.

Recombinant human parathyroid hormone (1-34) [teriparatide] improves both cortical and cancellous bone structure

Histomorphometry and microCT of 51 paired iliac crest biopsy specimens from women treated with teriparatide revealed significant increases in cancellous bone volume, cancellous bone connectivity density, cancellous bone plate-like structure, and cortical thickness, and a reduction in marrow star volume.

INTRODUCTION

We studied the ability of teriparatide (rDNA origin) injection [rhPTH(1-34), TPTD] to improve both cancellous and cortical bone in a subset of women enrolled in the Fracture Prevention Trial of postmenopausal women with osteoporosis after a mean treatment time of 19 months. This is the first report of a biopsy study after treatment with teriparatide having a sufficient number of paired biopsy samples to provide quantitative structural data.

METHODS

Fifty-one paired iliac crest bone biopsy specimens (placebo [n = 19], 20 microg teriparatide [n = 18], and 40 microg teriparatide [n = 14]) were analyzed using both two-dimensional (2D) histomorphometry and three-dimensional (3D) microcomputed tomography (microCT). Data for both teriparatide treatment groups were pooled for analysis.

RESULTS AND CONCLUSIONS

By 2D histomorphometric analyses, teriparatide significantly increased cancellous bone volume (median percent change: teriparatide, 14%; placebo, -24%; p = 0.001) and reduced marrow star volume (teriparatide, -16%; placebo, 112%; p = 0.004). Teriparatide administration was not associated with osteomalacia or woven bone, and there were no significant changes in mineral appositional rate or wall thickness. By 3D cancellous and cortical bone structural analyses, teriparatide significantly decreased the cancellous structure model index (teriparatide, -12%; placebo, 7%; p = 0.025), increased cancellous connectivity density (teriparatide, 19%; placebo, - 14%; p = 0.034), and increased cortical thickness (teriparatide, 22%; placebo, 3%; p = 0.012). These data show that teriparatide treatment of postmenopausal women with osteoporosis significantly increased cancellous bone volume and connectivity, improved trabecular morphology with a shift toward a more plate-like structure, and increased cortical bone thickness. These changes in cancellous and cortical bone morphology should improve biomechanical competence and are consistent with the substantially reduced incidences of vertebral and nonvertebral fractures during administration of teriparatide.

On the non-inferiority of a diagnostic test based on paired observations

Non-inferiority of a diagnostic test to the standard or the optimum test is a common issue in medical research. Often we want to determine if a new diagnostic test is as good as the standard reference test. Sometimes we are interested in an inexpensive test that may have an acceptably inferior sensitivity or specificity. While hypothesis testing procedures and sample size formulae for the equivalence of sensitivity or specificity alone have been proposed, very few studies have discussed simultaneous comparisons of both parameters. In this paper, we present three different testing procedures and sample size formulae for simultaneous comparison of sensitivity and specificity based on paired observations and with known disease status. These statistical procedures are then used to compare two classification rules that identify women for future osteoporotic fracture. Simulation experiments demonstrate that the new tests and sample size formulae give the appropriate type I and II error rates. Differences between our approach and the approach of Lui and Cumberland are discussed.

Severity of prevalent vertebral fractures and the risk of subsequent vertebral and nonvertebral fractures: results from the MORE trial

Prevalent vertebral fractures and baseline bone mineral density (BMD) predict subsequent fracture risk. The objective of this analysis is to examine whether baseline vertebral fracture severity can predict new vertebral and nonvertebral fracture risk. In the randomized, double-blind 3-year Multiple Outcomes of Raloxifene Evaluation (MORE) trial, 7705 postmenopausal women with osteoporosis (low BMD or prevalent vertebral fractures) were randomly assigned to placebo, raloxifene 60 mg/day, or raloxifene 120 mg/day. Post hoc analyses studied the association between baseline fracture severity and new fracture risk in the placebo group and the effects of placebo, raloxifene 60 mg/day, and raloxifene 120 mg/day on new fracture risk in women with the most severe prevalent vertebral fractures (n = 614). Vertebral fracture severity was visually assessed using semiquantitative analysis of radiographs and categorized by estimated decreases in vertebral heights. Reported new nonvertebral fractures were radiographically confirmed. Baseline vertebral fracture severity predicted vertebral and nonvertebral fracture risk at 3 years. In women without prevalent vertebral fractures, 4.3 and 5.5% had new vertebral and nonvertebral fractures, respectively. In women with mild, moderate, and severe prevalent vertebral fractures, 10.5, 23.6, and 38.1% respectively had new vertebral fractures, whereas 7.2, 7.7, and 13.8% respectively experienced new nonvertebral fractures. Number of prevalent vertebral fractures and baseline BMD also predicted vertebral fracture risk, but the severity of prevalent vertebral fractures was the only predictor of nonvertebral fracture risk and remained a significant predictor after adjustment for baseline characteristics, including baseline BMD. In patients with severe baseline vertebral fractures, raloxifene 60 mg/day decreased the risks of new vertebral [RR 0.74 (95% Cl 0.54, 0.99); P = 0.048] and nonvertebral (clavicle, humerus, wrist, pelvis, hip, and leg) fractures [RH 0.53 (95% CI 0.29, 0.99); P = 0.046] at 3 years. To prevent one new fracture at 3 years in women with severe baseline vertebral fractures with raloxifene 60 mg/day, the number needed to treat (NNT) was 10 for vertebral and 18 for nonvertebral fractures. Similar results were observed in women receiving raloxifene 120 mg/day. In summary, baseline vertebral fracture severity was the best independent predictor for new vertebral and nonvertebral fracture risk. Raloxifene decreased new vertebral and nonvertebral fracture risk in the subgroup of women with severe vertebral fractures at baseline. These fractures may reflect architectural deterioration, independent of BMD, leading to increased skeletal fragility.

Recognizing and reporting osteoporotic vertebral fractures

Vertebral fractures are the hallmark of osteoporosis, and occur with a higher incidence earlier in life than any other type of osteoporotic fractures. It has been shown that both symptomatic and asymptomatic vertebral fractures are associated with increased morbidity and mortality. Morbidity associated with these fractures includes decreased physical function and social isolation, which have a significant impact on the patient's overall quality of life. Since the majority of vertebral fractures do not come to clinical attention, radiographic diagnosis is considered to be the best way to identify and confirm the presence of osteoporotic vertebral fractures in clinical practice. Traditionally, conventional lateral radiographs of the thoracolumbar spine have been visually evaluated by radiologists or clinicians to identify vertebral fractures. The two most widely used methods to determine the severity of such fractures in clinical research are the semiquantitative assessment of vertebral deformities, which is based on visual evaluation, and the quantitative approach, which is based on different morphometric criteria. In our practice for osteoporosis evaluation we use the Genant semiquantitative approach: an accurate and reproducible method tested and applied in many clinical studies. The newest generation of fan-beam DXA systems delivering "high-resolution" lateral spine images offers a potential practical alternative to radiographs for clinical vertebral fracture analysis. The advantages of using DXA over conventional radiographic devices are its minimal radiation exposure and high-speed image acquisition. It also allows combined evaluation of vertebral fracture status and bone mass density, which could become a standard for patient evaluation in osteoporosis. The disadvantage of DXA use is that upper thoracic vertebrae cannot be evaluated in a substantial number of patients due to poor imaging quality. We truly believe that the that there is a major role for radiologists and clinicians alike to carefully assess and diagnose vertebral fractures using standardized grading schemes such as the one outlined in this review. Quantitative morphometry is useful in the context of epidemiological studies and clinical drug trials; however, the studies would be flawed if quantitative morphometry were to be performed in isolation without additional adjudication by a trained and highly experienced radiologist or clinician.

Value of micro-CT as an investigative tool for osteochondritis dissecans

PURPOSE

To evaluate micro computed tomography (micro-CT) for the assessment of osteochondritis dissecans in comparison with histology.

MATERIAL AND METHODS

Osteochondritis dissecans lesions of 3 patients were evaluated using micro-CT (0.125 mA, 40 keV, 60 microm slice thickness, 60 microm isotropic resolution, entire sample) and light microscopy (toluidine blue, 3-5 microm slice thickness). The methods were compared regarding preparation time, detectability of tissue types and morphologic features of bone and cartilage.

RESULTS

Non-destructive micro-CT imaging of the entire sample was faster than histologic preparation of a single slice for light microscopy. Morphologic features of bone and cartilage could be imaged in a comparable way to histology. It was not possible to image cells or different tissue types of bone and cartilage with micro-CT.

CONCLUSION

Micro-CT is a fast, non-destructive tool that may be a supplement or, if detailed histologic information is not necessary, an alternative to light microscopy for the investigation of osteochondritis dissecans.

Impingement syndrome of the ankle following supination external rotation trauma: MR imaging findings with arthroscopic correlation

Our objective was to identify MR imaging findings in patients with syndesmotic soft tissue impingement of the ankle and to investigate the reliability of these imaging characteristics to predict syndesmotic soft tissue impingement syndromes of the ankle. Twenty-one ankles with chronic pain ultimately proven to have anterior soft tissue impingement syndrome were examined by MR imaging during January 1996 to June 2001. The MR imaging protocol included sagittal and coronal short tau inversion recovery (STIR), sagittal T1-weighted spin echo, axial and coronal proton-density, and T2-weighted spin-echo sequences. Nineteen ankles that underwent MR imaging during the same period of time and that had arthroscopically proven diagnosis different than impingement syndrome served as a control group. Fibrovascular scar formations distinct from the syndesmotic ligaments possibly related to syndesmotic soft tissue impingement were recorded. Arthroscopy was performed subsequently in all patients and was considered the gold standard. The statistical analysis revealed an overall frequency of scarred syndesmotic ligaments of 70% in the group with ankle impingement. Fibrovascular scar formations distinct from the syndesmotic ligaments presented with low signal intensity on T1-weighted images and remained low to intermediate in signal intensity on T2-weighted MR imaging. Compared with arthroscopy, MR imaging revealed a sensitivity of 89%, a specificity of 100%, and a diagnostic accuracy of 93% for scarred syndesmotic ligaments. The frequency of scar formation distinct from the syndesmotic ligaments in patients with impingement syndrome of the ankle was not statistically significantly higher than in the control group. In contrast to that, anterior tibial osteophytes and talar osteophytes were statistically significantly higher in the group with anterior impingement than in the control group. Conventional MR imaging was found to be insensitive for the diagnosis of syndesmotic soft tissue impingement of the ankle. Fibrovascular scar tissue distinct from syndesmotic ligaments is suggestive for the diagnosis of soft tissue impingement, but the reliability of these findings is still questionable.

Repair of erosions in rheumatoid arthritis does occur. Results from 2 studies by the OMERACT Subcommittee on Healing of Erosions

The committee was charged with determining whether healing of erosions in rheumatoid arthritis (RA) occurs. Two exercises were performed: The first asked the committee members, as a panel of experts, to express agreement or disagreement with the presence of improvement and features of bone reaction to injury in images submitted by members as examples of healing. The second presented panel members with 28 pairs of serial images, 14 chosen to illustrate progression and 14 chosen to illustrate repair. Agreement was tested on 8 items: global judgment on which image in the pair was better, relative size of the erosion in the 2 images, judgment on which image was first, presence and extent of sclerosis, cortication, filling-in, remodeling, and reconstituting normal structure. Our results showed good agreement, among the 15 respondents, on global assessment of which image was better and which image showed the smaller erosion. Correct assignment of sequence was only slightly better than expected by chance (in 65% of the cases). Agreement was poor regarding the presence of morphologic features of bone repair. A majority of a panel of experts agreed on which 2nd images in a set of paired, serial images represented improvement and which showed progression based on global assessment of which was better and on size of erosion. Features of bone repair were not distinctive and did not enable the panel to deduce the correct sequence of the serial images. This study provides evidence that repair of bone damage in RA does occur, resulting in some degree of improvement, which was recognized by a majority of a panel of experts.

Metallic artefacts in MR imaging: effects of main field orientation and strength

AIM

To determine the effect of metallic implant positioning on magnetic resonance (MR) imaging artefacts, and to determine the optimal imaging parameters for minimization of metallic artefacts.

MATERIALS AND METHODS

In a phantom and in three joints with non-ferromagnetic metallic implants imaged at 1.5 and/or at 0.2 T, we examined the influence of the static magnetic field (B(0)) strength and orientation, frequency-encoding direction, and type of imaging sequence on metallic artefacts.

RESULTS

The impact of artefacts caused by metallic objects depends mainly on the relationship between the anatomy of interest and the orientation of the object relative to the direction of B(0). The main field strength plays a less important role, but its orientation depends on the type of MR imager.

CONCLUSION

MR artefacts can be easily minimized by optimally positioning patients with metallic implants in the magnet. Knowledge of how this influences MR imaging is helpful in patient selection and guiding limb positioning.

Palangeal quantitative ultrasound, phalangeal morphometric variables, and vertebral fracture discrimination

The aim of this study was to evaluate the association among phalangeal morphometric parameters, amplitude-dependent speed of sound (AD-SOS), ultrasound bone profile index (UBPI), and spinal bone mineral density (BMD) and fracture status. One hundred women (controls, mean age 53 +/- 12 years) and 40 osteoporotic women (mean age 59 +/- 7 years) with atraumatic fractures, diagnosed by spinal radiographs, were investigated. Quantitative ultrasound (QUS) assessment was performed using the DBM Sonic 1200. Morphological properties of the phalanges were measured from a digitized X-ray image of the hand acquired using industrial film. Spinal BMD was assessed by dual X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). An increase in medullary canal width and a decrease in cortical thickness with aging were observed from the morphometric analysis of the hand radiographs. This phenomenon can be attributed mainly to endosteal resorption. QUS measurements at the phalanges were not significantly related to finger thickness (r <0.20, n.s.). They were significantly correlated to medullary canal ratio (r = -0.57, P <0.0001, for AD-SOS and r = -0.64, P <0.0001, for UBPI) and to cortical thickness (r = +0.52, P <0.0001 for AD-SOS and r = +0.59, P <0.0001 for UBPI). In the discrimination analysis between nonfractured and atraumatic vertebral fracture subjects we found that cortical thickness at the level of the phalanges were similar to lumbar spine BMD. The age and BMI-adjusted odds ratio ranged from 2.0 to 3.1 for QUS, 4.28 for BMD by QCT, 4.1 for BMD by DXA, and 4.1 for cortical thickness. We conclude from these data that phalangeal QUS is related to cortical thickness, which in turn is influenced by endosteal bone resorption occurring in association with spinal osteoporosis.

Arthroscopic evaluation of potential structure-modifying drug in osteoarthritis of the knee. A multicenter, randomized, double-blind comparison of tenidap sodium vs piroxicam

OBJECTIVE

To test the hypothesis that tenidap has a structure-modifying effect in human knee osteoarthritis.

DESIGN

STUDY

multicenter, prospective, randomized, double blind, 1 year duration.

PATIENTS

primary painful knee osteoarthritis (ACR criteria) of the medial tibiofemoral compartment, medial joint space width > or =2mm, at least 10% of one cartilage surface of the medial compartment affected by superficial fibrillation or worse at baseline arthroscopy. STUDY MEDICATION: once daily dosage of either tenidap 40 mg, tenidap 120 mg or piroxicam 20mg. STUDY ENDPOINTS: bilateral extended weight-bearing X-rays and knee arthroscopy under local anaesthesia were done at entry and after 1 year. Joint space width was measured in millimeters at the narrowest point of the medial compartment. Chondropathy was scored by using reader's overall assessment (VAS score, 100mm) and Société Française d'Arthroscopie (SFA) score (0-100).

RESULTS

Patients (665) were randomized and 494 completed the study. After 1 year, intra-group radiological changes and radiological difference between both tenidap groups and the piroxicam group did not reach statistical significance. The intra-group arthroscopic deterioration of chondropathy was low, but statistically significant in the three study groups. However, there was no statistically significant difference between both tenidap groups and the piroxicam group.

CONCLUSIONS

This study failed to demonstrate any difference between the treatment arms with regard to the structural progression of medial knee osteoarthritis as measured by radiography and arthroscopy. Arthroscopy did, however, appears to be more sensitive in detecting disease progression than the weight-bearing radiographs with fully extended knees. This study shows that it is possible to complete a large international trial using arthroscopy as an outcome measure of articular cartilage.

Comparison of fixed-flexion positioning with fluoroscopic semi-flexed positioning for quantifying radiographic joint-space width in the knee: test-retest reproducibility

OBJECTIVE

To compare fixed-flexion radiography of the knee with fluoroscopic semi-flexed radiography in terms of the reproducibility of measurements of minimum joint-space width (JSW) in the medial femorotibial joint.

METHODS

Posteroanterior radiographs of the right knees of 18 normal volunteers were acquired with the patients standing on an upright fluoroscopy table, the feet externally rotated 10 degrees and the toes touching the vertical table. Knees were positioned and radiographed with two different techniques: (1) semi-flexed positioning under fluoroscopic guidance using a horizontal X-ray beam; and (2) fixed-flexion positioning, with the knees and thighs touching the vertical table, using 10 degrees caudal beam angulation without fluoroscopy. Foot maps were drawn in each case. Subjects were repositioned and radiographed twice using each technique. The posteroanterior beam angle that optimally projected the medial tibia plateau with the patient in the fixed-flexion position was also determined for each subject in a separate examination using fluoroscopy. Ten patients with osteoarthritis were also examined with the fixed-flexion technique using a conventional radiographic unit. Minimum medial joint-space width (JSW) in the medial femorotibial joint was measured manually with a graduated lens and also with a semi-automated computer algorithm.

RESULTS

Reproducibility errors (root-mean-square SD) for manual and automated JSW measurement were 0.2 mm and 0.1 mm, respectively, for fluoroscopic semi-flexed positioning in volunteers; 0.3 mm and 0.1 mm, respectively, for fixed-flexion positioning in volunteers; and 0.2 mm and 0.1 mm, respectively, for fixed-flexion positioning in osteoarthritic patients. The optimal beam angle for visualizing the joint space was 9.0 degrees +/-3.6 degrees.

CONCLUSION

Fixed-flexion, non-fluoroscopic radiography of the knee can provide reproducible JSW measurement using widely available X-ray equipment. This technique is more feasible for multicenter clinical studies and routine clinical use than are methods that rely on fluoroscopic alignment of the tibial plateau.

New radiographic-based surrogate outcome measures for osteoarthritis of the knee

OBJECTIVE

Minimum joint space width (mJSW) between the femoral condyle and tibial plateau is currently the principal radiographic outcome measure for knee osteoarthritis (OA). While mJSW measurement has been proven effective, there is a need for quantitative measures with greater sensitivity to OA so studies of disease modifying trials can be performed more quickly and with fewer subjects. Also, mJSW is a single outcome measure that does not reflect all disease changes. Here we present a study of new radiograph-based outcome measures to quantify OA progression.

DESIGN

Our goal is made possible by a software algorithm that delineates both the edge of the tibial plateau and the femoral condyle on digitized knee radiographs. We also developed a new coordinate system based on anatomical landmarks to facilitate measurement of the outcome measures. We studied measurements of joint space width (JSW) and average JSW at fixed locations along the joint interface. The outcome measures were tested using duplicate acquisitions made from 16 OA and 18 normal knees. Reproducibility was quantified by the root-mean square standard deviation and the coefficient of variation.

RESULTS

We found that the reproducibility for all outcome measures was better than or similar to that for mJSW. Despite a slightly higher reproducibility error for some new outcome measures compared to mJSW, they are potentially valuable since they reflect independent disease changes.

CONCLUSION

We have demonstrated new reproducible radiographic outcome measures to quantify OA progression with the potential to be an improvement over standard minimum joint space width.

Accuracy of CT-based thickness measurement of thin structures: modeling of limited spatial resolution in all three dimensions

Measurement of the width of thin structures such as the cortical shell of the vertebral body or femoral neck with computed tomography (CT) is limited by the spatial resolution of the CT system. Limited spatial resolution exists both within the CT image plane and perpendicular to it and can be described by the in-plane point spread function (PSF) and the across-plane slice sensitivity profile (SSP), respectively. The goal of this study was to confirm that errors of thickness measurement of thin structures critically depend on the spatial positioning of the object and the spatial resolution limitations of CT in all three dimensions, and to assess the size of the errors themselves. We compared computer models that incorporated both effects to experimentally assessed cortical thicknesses of the European Spine Phantom. Analysis included varying CT slice width, the orientation of measurement and angle beta of misalignment of longitudinal scanner and phantom axes. Agreement of models with measurements was good in all configurations with an overall error of 0.17 mm. This showed that PSF and SSP are adequate system characteristics to predict deviation of measured values from true widths. Errors between measurements and true cortical thickness values delta(true) averaged to 1.5 mm were strongly positively correlated with slice width d and beta. When the across-plane partial volume effect was eliminated, limited in-plane resolution still accounted for overestimation of delta(true) by 0.68 (137%), 0.27 (27%), and 0.06 mm (4%) for delta(true)=0.5, 1.0, and 1.5 mm, respectively. For delta(true) of 1.0 mm and above, it was shown that although the absolute cortical thickness values might not be accurately measurable, relative differences between two values are reflected in measurement. Implications for cortical thickness measurement are that the spinal cortical shell is too thin, whereas accurate assessment at locations of the femoral neck exhibiting a thicker cortical shell of both difference and absolute values should be possible with CT even for larger misalignment angles, especially when a smaller CT slice width is chosen.

Assessment of prevalent and incident vertebral fractures in osteoporosis research

Vertebral fractures are the hallmark of osteoporosis, and it has been shown that the presence of vertebral fractures adds to the risk of future osteoporotic fractures. Thus, the evaluation of spinal radiographs for prevalent or incident vertebral fractures is important in the clinical evaluation of patients with osteoporosis, in clinical drug trials for osteoporosis treatment and in the epidemiologic evaluation of populations at risk for osteoporosis. Traditionally, conventional lateral radiographs of the thoracolumbar spine have been analyzed visually by radiologists or experienced clinicians to identify vertebral fractures in patients with clinical indications. Epidemiologic studies or clinical drug trials in osteoporosis research have considerably different requirements and expectations. To reduce potential subjectivity in qualitative readings and to provide definable, reproducible and objective methods to detect vertebral fracture, and to accommodate the assessment of large numbers of radiographs, various morphometric approaches have been explored and employed. However, potential deficiencies in morphometry have led to a renewed interest in standardized qualitative visual approaches for defining vertebral fractures and visual criteria. Numerous studies have shown that semiquantitative interpretation, after careful centralized training and standardization, can produce results with excellent intra- and interobserver reproducibility. We firmly believe that the experience from several studies has shown that there is a major role for radiologists and clinicians alike to carefully assess and diagnose vertebral fractures using standardized grading schemes such as the one proposed in this review. In the context of epidemiologic studies and clinical drug trials, quantitative morphometry may be used; however, the studies would be flawed if quantitative morphometry were to be performed in isolation without additional adjudication by a trained and highly experienced radiologist or clinician.

Clinical applications of body composition measurements using DXA

Dual-energy X-ray absorptiometry (DXA) scanning was primarily developed for the diagnosis of osteoporosis and was initially applied to studies of the clinically important sites of the lumbar spine, femoral neck, and forearm. The rapid adoption of DXA has led to the development of different, competing generations of equipment. Improvements have been achieved through advances in X-ray generation and detection technology, modification of data acquisition protocols, and implementation of more sophisticated image analysis algorithms. As a result, DXA has been extended to allow the study of the total skeleton and its regional parts, as well as soft-tissue composition measurement. The three major components of the body: fat mass, lean mass, and bone mineral mass, can now be easily measured using a single whole body DXA scan with high precision and low scanning time. The comprehensive view of body composition provided by DXA makes it an attractive technique for a variety of clinical applications such as the prevention of cardiovascular and metabolic diseases, clinical management of different chronic diseases, and monitoring of the impact of treatment regimens on body tissues. In this article we review the contribution DXA has made to the understanding of body composition in clinical studies in adults.

Recombinant human bone morphogenetic protein-2 for treatment of open tibial fractures: a prospective, controlled, randomized study of four hundred and fifty patients

BACKGROUND

The treatment of open fractures of the tibial shaft is often complicated by delayed union and nonunion. The objective of this study was to evaluate the safety and efficacy of the use of recombinant human bone morphogenetic protein-2 (rhBMP-2; dibotermin alfa) to accelerate healing of open tibial shaft fractures and to reduce the need for secondary intervention.

METHODS

In a prospective, randomized, controlled, single-blind study, 450 patients with an open tibial fracture were randomized to receive either the standard of care (intramedullary nail fixation and routine soft-tissue management [the control group]), the standard of care and an implant containing 0.75 mg/mL of rhBMP-2 (total dose of 6 mg), or the standard of care and an implant containing 1.50 mg/mL of rhBMP-2 (total dose of 12 mg). The rhBMP-2 implant (rhBMP-2 applied to an absorbable collagen sponge) was placed over the fracture at the time of definitive wound closure. Randomization was stratified by the severity of the open wound. The primary outcome measure was the proportion of patients requiring secondary intervention because of delayed union or nonunion within twelve months postoperatively.

RESULTS

Four hundred and twenty-one (94%) of the patients were available for the twelve-month follow-up. The 1.50-mg/mL rhBMP-2 group had a 44% reduction in the risk of failure (i.e., secondary intervention because of delayed union; relative risk = 0.56; 95% confidence interval = 0.40 to 0.78; pairwise p = 0.0005), significantly fewer invasive interventions (e.g., bone-grafting and nail exchange; p = 0.0264), and significantly faster fracture-healing (p = 0.0022) than did the control patients. Significantly more patients treated with 1.50 mg/mL of rhBMP-2 had healing of the fracture at the postoperative visits from ten weeks through twelve months (p = 0.0008). Compared with the control patients, those treated with 1.50 mg/mL of rhBMP-2 also had significantly fewer hardware failures (p = 0.0174), fewer infections (in association with Gustilo-Anderson type-III injuries; p = 0.0219), and faster wound-healing (83% compared with 65% had wound-healing at six weeks; p =0.0010).

CONCLUSIONS

The rhBMP-2 implant was safe and, when 1.50 mg/mL was used, significantly superior to the standard of care in reducing the frequency of secondary interventions and the overall invasiveness of the procedures, accelerating fracture and wound-healing, and reducing the infection rate in patients with an open fracture of the tibia.

Femoral neck and intertrochanteric fractures: radiographic indicators of fracture healing

Serial hip radiographs from 280 patients with proximal femoral fractures were analyzed retrospectively by 3 radiologists to evaluate conventional radiographic healing patterns. Patients with hemiarthroplasty or insufficient follow-up were excluded. In the remaining 41 patients, the fracture line and callus was assessed. Intertrochanteric fractures demonstrated increasing callus and sclerosis at the fracture site. No such association was seen in femoral neck fractures. Traditional indicators of fracture healing cannot be readily applied at the hip. Radiographic features relate more to fracture type and fixation method.

Effects of raloxifene on fracture severity in postmenopausal women with osteoporosis: results from the MORE study. Multiple Outcomes of Raloxifene Evaluation

Raloxifene reduces the risk of new vertebral fractures, but its effect on the severity of these new fractures has not been determined. The MORE (Multiple Outcomes of Raloxifene Evaluation) trial studied the effects of placebo, raloxifene 60 or 120 mg/day in 7,705 postmenopausal women with osteoporosis. Radiologists assessed new vertebral fractures from radiographs and graded the fracture severity as normal (no fracture) or mild, moderate or severe. New clinical vertebral fractures were defined as new vertebral fractures associated with symptoms, such as back pain, and confirmed in radiographs. In the total study population, the majority (76.4%) of the women who experienced clinical vertebral fractures were diagnosed with new moderate/severe vertebral fractures. In turn, women with moderate/severe vertebral fractures in the overall population were more likely to experience clinical symptoms suggestive of fracture than were women who had new mild-only vertebral fractures. The incidence of new mild-only and moderate/severe fractures was the same in women without prevalent vertebral fractures, but the incidence of new moderate/severe fractures was 2 to 3 times higher than that for new mild-only fractures in women with prevalent vertebral fractures. Raloxifene 60 mg/day decreased the risk of at least 1 new moderate/severe vertebral fracture by 61% in women without prevalent vertebral fractures [RR 0.39 (95% CI 0.17, 0.69)], and by 37% in women with prevalent vertebral fractures [RR 0.63 (95% CI 0.49, 0.83)] at 3 years. The risk reductions for at least 1 new moderate/severe vertebral fracture were not significantly different between the raloxifene doses, in women with and without prevalent vertebral fractures. The effects of raloxifene on significantly decreasing the risk of new moderate/severe vertebral fractures may explain the risk reduction for new painful clinical vertebral fractures observed with raloxifene, and is particularly important in postmenopausal women with severe osteoporosis who are at higher risk for moderate or severe fractures.