Race and sex differences in bone mineral density and geometry at the femur.

INTRODUCTION: Differences in osteoporotic hip fracture incidence between American whites and blacks and between women and men are considered to result, in part, from differences in bone mineral density and geometry at the femur. The aim of this study was to quantify differences in femoral bone density and geometry between a large sample of healthy American white and black women and men. SUBJECTS AND METHODS: Healthy American white (n=612) and black (n=164) premenopausal women, aged 23 to 57 years, and healthy American white (n=492) and black (n=169) men, aged 20 to 63 years, had volumetric bone mineral density (vBMD) and geometry variables measured at the femur by computerized tomography (CT), and areal bone mineral density (aBMD) at femoral neck measured by dual X-ray absorptiometry (DXA). RESULTS: American blacks had higher vBMD at the femoral neck and femoral shaft cortex than American whites whereas femoral axis length and femoral neck area were not different. Men had lower vBMD at the femoral neck and femoral cortex than women but had greater femoral axis length and femoral neck area than women. The higher aBMD in American blacks than whites persisted after correction for measured area whereas the higher aBMD in men than women disappeared. CONCLUSIONS: At the femoral neck, American whites have lower bone density than American blacks but similar geometry. Women have higher bone density than men in both races but have smaller geometry variables. The differences in bone density may account in part for the differences in hip fracture incidence between American blacks and whites, whereas the differences in femur size may account for the differences in hip fracture rates between men and women.

Comparison of quantitative and semiquantitative indicators of joint space narrowing in subjects with knee osteoarthritis.

OBJECTIVE: To compare quantitative estimates of change in joint space width (JSW) with semiquantitative ratings of the progression of joint space narrowing (JSN) with respect to sensitivity to change over time. METHODS: 431 obese women 45 to 64 years old with unilateral radiographic knee osteoarthritis were randomised to 30 months' treatment with doxycycline 100 mg twice daily or placebo. Quantitative estimates of change in JSW in the medial tibiofemoral compartment from fluoroscopically assisted semiflexed AP radiographs were obtained at baseline and 16 and 30 months after randomisation. Radiographic JSN was rated (0-3 scale) in the same images by two readers using a standard atlas. Changes in overall severity of knee osteoarthritis were derived from gradings of conventional standing AP radiographs at baseline and 30 months, with blinding to treatment group and chronological order of examination. RESULTS: Follow up radiographs were obtained from 381 subjects (88%) at 16 months and from 367 (85%) at 30 months. The treatment groups did not differ in the frequency of significant loss of JSW by dichotomous criteria (> or =0.5 mm, > or =1.0 mm, > or =20%, or > or =50% of baseline JSW). Progressors and non-progressors, as defined by each of the dichotomous outcomes, differed significantly in mean value for quantitative measurement of change in JSW at 30 months (p< or =0.001). CONCLUSIONS: Quantitative and semiquantitative indicators of progression of osteoarthritis in fluoroscopically standardised radiographs of osteoarthritic knees are highly related, but the effect of doxycycline on articular cartilage thickness was more easily detected with quantitative measurements of change in JSW than with semiquantitative ratings of JSN.

Risk factors for progression of tibiofemoral osteoarthritis: an analysis based on fluoroscopically standardised knee radiography.

OBJECTIVE: To evaluate risk factors for progressive radiographic changes of knee osteoarthritis using a standardised fluoroscopically assisted protocol for knee radiography. SUBJECTS: (n = 319) with unilateral or bilateral knee osteoarthritis underwent a fluoroscopically standardised x ray examination of the knees (semiflexed AP view) and assessment with the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index at baseline and at 30 months. Tibiofemoral joint space narrowing and osteophytosis were graded in randomly ordered serial radiographs by consensus of two readers using standard pictorial atlases. RESULTS: Progression of joint space narrowing was inversely related to baseline joint space width (odds ratio (OR) = 0.67/1.4 mm (95% confidence interval (CI), 0.49 to 0.91)) and positively associated with patellofemoral osteoarthritis (OR = 3.36 (1.83 to 6.18)). Osteophyte growth was inversely related to overall severity (number and size) of osteophytosis at baseline (OR = 0.47/1.8 points on a 12 point osteophyte severity scale (95% CI, 0.33 to 0.66)), and directly related to baseline stiffness (OR = 1.39/2.1 WOMAC scale points (95% CI, 1.09 to 1.77)) and the presence of patellofemoral osteoarthritis at baseline (OR = 2.31 (1.37 to 3.88)). CONCLUSIONS: Progression of both joint space narrowing and osteophyte growth are predicted by the severity of the respective radiographic features of osteoarthritis at baseline and by the presence of patellofemoral osteoarthritis. In addition, knee stiffness is a risk factor for progressive osteophyte growth.

Development of radiographic changes of osteoarthritis in the "Chingford knee" reflects progression of disease or non-standardised positioning of the joint rather than incident disease.

OBJECTIVE: To ascertain the extent to which the "Chingford knee" (that is, contralateral knee of the middle aged, obese, female patient with unilateral knee osteoarthritis (OA)) is a high risk radiographically normal joint as opposed to a knee in which radiographic changes of OA would have been apparent in a more extensive radiographic examination. METHODS: Subjects were 180 obese women, aged 45-64 years, with unilateral knee OA, based on the standing anteroposterior (AP) view. Subjects underwent a series of radiographic knee examinations: semiflexed AP, supine lateral, and Hughston (patellofemoral (PF)) views. Bony changes of OA were graded by consensus of two readers. Medial tibiofemoral joint space width was measured by digital image analysis. Knee pain was assessed by the WOMAC OA Index after washout of all OA pain drugs. RESULTS: Despite the absence of evidence of knee OA in the standing AP radiograph, only 32 knees (18%) were radiographically normal in all other views. Ninety four knees (52%) exhibited TF knee OA in the semiflexed AP and/or lateral view. PF OA was seen in 121 knees (67%). Subjects with PF OA reported more severe knee pain than those without PF OA (mean WOMAC scores 9.9 v 8.3, p<0.05). CONCLUSION: The Chingford knee is not a radiographically normal joint. The high rate of incidence of OA reported previously for this knee ( approximately 50% within two years) may also reflect progression of existing OA or changes in radioanatomical positioning at follow up that showed evidence of stable disease that was present at baseline.

Multisection CT: scanning techniques and clinical applications.

Multisection computed tomography (CT) was introduced in 1992 with the advent of dual-section-capable scanners and was improved in 1998 following the development of quad-section technology. With a recent increase in gantry speed from one to two revolutions per second, multisection CT scanners are now up to eight times faster than conventional single-section helical CT scanners. The benefits of quad-section CT relative to single-section helical CT are considerable. They include improved temporal resolution, improved spatial resolution in the z axis, increased concentration of intravascular contrast material, decreased image noise, efficient x-ray tube use, and longer anatomic coverage. These factors substantially increase the diagnostic accuracy of the examination. The multisection CT technique has enabled faster and superior evaluation of patients across a wide spectrum of clinical indications. These include isotropic viewing, musculoskeletal applications, use of multiplanar reformation in special situations, CT myelography, long coverage and multiphase studies, CT angiography, cardiac scoring, evaluation of brain perfusion, imaging of large patients, evaluation of acute chest pain or dyspnea, virtual endoscopy, and thin-section scanning with retrospective image fusing. Multisection CT is superior to single-section helical CT for nearly all clinical applications.

Use of radiography, computed tomography and magnetic resonance imaging for evaluation of navicular syndrome in the horse.

Radiographic evaluation of navicular syndrome is problematic because of its inconsistent correlation with clinical signs. Scintigraphy often yields false positive and false negative results and diagnostic ultrasound is of limited value. Therefore, we assessed the use of computed tomography and magnetic resonance imaging in a horse with clinical and radiographic signs of navicular syndrome. Cadaver specimens were examined with spiral computed tomographic and high-field magnetic resonance scanners and images were correlated with pathologic findings. Radiographic changes consisted of bony remodeling, which included altered synovial fossae, increased medullary opacity, cyst formation and shape change. These osseous changes were more striking and more numerous on computed tomographic and magnetic resonance images. They were most clearly defined with computed tomography. Many osseous changes seen with computed tomography and magnetic resonance imaging were not radiographically evident. Histologically confirmed soft tissue alterations of the deep digital flexor tendon, impar ligament and marrow were identified with magnetic resonance imaging, but not with conventional radiography. Because of their multiplanar capability and tomographic nature, computed tomography and magnetic resonance imaging surpass conventional radiography for navicular imaging, facilitating earlier, more accurate diagnosis. Current advances in imaging technology should make these imaging modalities available to equine practitioners in the future.

Magnetic resonance imaging of osteoarthritis.

Considering the plethora of imaging protocols, joint-specific orientations, and potential artifacts, the design and interpretation of MR imaging examination is difficult. Like a physical examination, these considerations must be tailored to the specific tissue, joint, and clinical question under consideration. Shortcomings of MR imaging include the lack of consensus among radiologists with respect to which protocols best image articular joints. To date, few prospective studies have been undertaken to assess osteoarthritis by MR imaging. Diagnostic imaging is central to staging the severity of osteoarthritis and assessing the efficacy of therapeutic osteoarthritis. Plain film radiography is insensitive for identifying early changes of osteoarthritis. Tailored MR imaging, producing high spatial and or contrast resolution images, is proving to be an important tool in the early detection and surveillance of osteoarthritis progression. Future therapeutic techniques, such as chondrocyte transplantation, use of growth factors, or cartilage protease inhibitors requires high resolution and volumetric MR imaging studies for accurate identification of focal articular cartilage defects and generalized cartilage loss. Creation of cartilage models by three-dimensional MR image rendering may be helpful for preoperative planning of orthopedic surgical procedures in advanced cases of osteoarthritis. More work needs to be done in high resolution and volumetric MR imaging of articular cartilage. Given the availability of new disease-modifying treatments designed to prevent, delay the progression of, or reverse osteoarthritis, additional prospective MR imaging studies need to be undertaken to improve the reproducibility of MR imaging as a primary outcome measure in the evaluation of osteoarthritis. Interinstitutional standardization of specific MR imaging magnet strengths, surface coils, joint orientations, sequences used, scoring systems and quality assurance methodologies are needed to establish the reproducibility of MR imaging and interpretation for assessment of patients with osteoarthritis.

Field test of the reproducibility of automated measurements of medial tibiofemoral joint space width derived from standardized knee radiographs.

OBJECTIVE: To estimate the reproducibility of computerized measurements of minimum joint space width (JSW) in the medial tibiofemoral compartment in knee radiographs (semiflexed AP view) obtained from clinical radiology units. METHODS: Technologists from 5 clinical radiology units were trained in the performance of the fluoroscopically assisted semiflexed AP knee examination. Each of 44 subjects (34 with knee osteoarthritis, OA, 10 with bilaterally normal knees) were examined within 7 days in 2 of the 5 units. The examination in each unit was repeated 1 week later. Minimum JSW was measured on digitized radiographic images with computer software that corrected for radiographic magnification. RESULTS: Despite ongoing quality control by technologists, 11% of radiographs were flawed with respect to the protocol standard for knee rotation and 36% with respect to the standard for knee flexion. The standard error of measurement (SEm) of JSW in 174 knees that were examined twice in the same unit was 0.32 mm (SEm = 0.25 mm for the subset of 76 paired radiographs with uniformly high quality). The overall between-unit SEm was 0.45 mm. Within-unit, but not between-unit, precision was related to the technical quality of the radiographs. Precision was unrelated to subject age, sex, race, weight, and radiographic severity of knee OA. CONCLUSION: The within-unit precision of JSW measurements from all pairs of semiflexed views (irrespective of technical quality) represented a notable improvement over that observed in radiographs with flawed knee rotation or flexion (as would be the case in conventional extended knee views). In future applications of this technique, assurance of technical quality by an independent observer should result in a level of measurement precision that will permit the design of clinical trials of disease modifying OA drugs with fewer subjects and/or shorter duration of treatment than is possible with conventional knee radiography.

Locus heterogeneity of autosomal dominant osteopetrosis (ADO).

Autosomal dominant osteopetrosis (ADO), is a heritable disorder that results from a failure of osteoclast-mediated bone resorption. The etiology of the disorder is unknown. A previous linkage study of one Danish family mapped an ADO locus to chromosome 1p21. We have studied two families from Indiana with ADO. The present study sought to determine if the ADO gene in these families was also linked to chromosome 1p21. We used six microsatellite repeat markers, which demonstrated linkage to the 1p21 ADO locus in the Danish study, to perform linkage analysis in the new kindreds. Multipoint analysis excluded linkage of ADO to chromosome 1p21 (logarithm of the odds score < -7.00) in both families. In addition, no haplotype segregated with the disorder in either family. In summary, the present investigation ruled out linkage of ADO to chromosome 1p21 in two families from Indiana. Our results demonstrate that there is locus heterogeneity of this disorder; therefore, mutations in at least two different genes can give rise to the ADO phenotype.

A technique for magnetic resonance imaging of equine cadaver specimens.

We tested an adaptation of a technique for performing magnetic resonance (MR) imaging of human cadaver limbs in the horse. The forelimbs from a normal horse were collected, frozen, and sealed with a paraffin-polymer combination prior to imaging with either a high- or midfield magnetic resonance scanner. Each forelimb was defrosted, scanned, and refrozen on two separate occasions. A five-point scale was used to evaluate the quality of each set of sagittal and transverse, T1-weighted images of each digit. There was no difference in image quality between first and second scans of either specimen (p > 0.05). We conclude that this technique allows investigators to bank tissue specimens for future magnetic resonance imaging without significant loss of image quality.

World Wide Web interface to digital imaging and communication in medicine-capable image servers.

As a trial project, the Indiana University Department of Radiology has develop[ed a low-cost manner of distributing radiological images throughout a medical environment using the World Wide Web (WWW). The interface requires the user to have a WWW-browser client, such as Netscape, running on UNIX, PC, or Macintosh platforms. A forms-based interface allows the user to query several DICOM-capable machines at the machine, patient, study, series, and image levels. Once an image transfer is initiated, images are prewindowed from 16- to 8-bits, compressed using public domain Joint Photographic Expert Group (JPEG) compression routines, transferred to the WWW client program, and decompressed and displayed using a locally selected image viewing program. At the currently implemented level of compression (75% quality), the entire fetch-transform-JPEG-display process takes 2 to 5 seconds over Ethernet, depending on the platform used.

Osteonecrosis, transient osteoporosis, and transient bone marrow edema: current concepts.

Osteonecrosis, transient osteoporosis, and transient bone marrow edema are closely related diseases that may have an overlapping clinical and radiographic presentation, thus creating difficulty in establishing a diagnosis. Close scrutiny of MR images may aid in distinguishing the pattern of osteonecrosis from other conditions, but in other cases careful clinical and radiologic follow up may be required. The pathogenesis, radiologic diagnosis, and clinical relevance of these conditions are described and reviewed in this article.

Kinematic magnetic resonance imaging of the normal shoulder: assessment of the labrum and capsule.

OBJECTIVE: To examine the normal shoulder, specifically the labrum and the capsule, with kinematic magnetic resonance imaging (MRI) in asymptomatic volunteers. SUBJECTS AND METHODS: Fourteen asymptomatic volunteers 22 to 53 years of age were studied with a 1.5-T Signa Advantage imager (GE Medical Systems, Milwaukee). Successive static gradient-echo images were obtained in the transverse plane at the mid-glenoid level as the shoulder was successively positioned from full internal to full external rotation. These images were correlated with standard transverse T1-weighted spin-echo images and gradient-echo volume images obtained in the neutral position. RESULTS: The anterior labrum was slightly mobile during rotation in 11 subjects and changed shape from blunted or round to triangular in 8 subjects. A wide variation in morphologic features of the anterior labrum was observed. During rotation, a slight increase in signal intensity was noted in the anterior labrum of five of the subjects. The posterior labrum maintained a relatively stable triangular shape in most cases. Dynamic study allowed assessment of the anterior capsule insertion in all cases. Three subjects had type 1 and 11 had type 2 capsular insertion. No cases of type 3 insertion were identified. CONCLUSIONS: Variation in the shape and signal intensity of the anterior labrum observed in normal asymptomatic volunteers during transverse kinematic examination of the shoulder should be taken into account during evaluation of shoulder instability, since this variation may be clinically insignificant. Kinematic MRI allows easy evaluation of the anterior capsule.

US of the snapping iliopsoas tendon.

PURPOSE: To determine the value of ultrasound (US) in the diagnosis of snapping iliopsoas tendon. MATERIALS AND METHODS: In three patients, dynamic US of the hip was performed as the flexed, abducted, and externally rotated hip was extended. The contralateral hip was also evaluated. Hip arthrography was performed in all three patients, magnetic resonance imaging in two, and iliopsoas bursography in two, which was successful in only one case. One patient underwent surgical release of the iliopsoas tendon. RESULTS: At US, an abnormal jerk of the iliopsoas tendon during hip motion was correlated with the painful audible snap. The motion of the contralateral iliopsoas tendon was smooth. No intraarticular abnormality was found in two patients, and an associated labral tear was suspected at arthrography in the third patient. The patient who underwent surgical release of the iliopsoas tendon had great improvement. CONCLUSION: US is a useful dynamic noninvasive technique for the diagnosis of snapping iliopsoas tendon.

Amyloidosis of the shoulder in patients on chronic hemodialysis: sonographic findings.

OBJECTIVE: The purpose of this study was to determine the sonographic findings of amyloidosis in shoulders of patients on chronic hemodialysis. SUBJECTS AND METHODS: Sonograms were obtained for 19 shoulders of 11 patients on chronic hemodialysis with clinical findings suggestive of amyloidosis. Five patients had biopsy-proven amyloidosis, and one patient had positive shoulder joint fluid aspirate. The thicknesses of the following structures were measured: the rotator cuff, the subacromial-subdeltoid bursa, and the long head of the biceps tendon and its synovial sheath. The presence of intra- or periarticular masses or nodules, hyperechoic areas, bony erosions, and calcifications was specifically assessed. Shoulder sonograms from dialysis patients were compared with normal sonograms obtained for 20 asymptomatic shoulders of patients without renal disease. RESULTS: The mean rotator cuff thickness in the patients with amyloidosis was significantly greater than that in the normal group (p < .0001). Ten shoulders of six patients with amyloidosis but none of the control subjects had a rotator cuff thickness greater than 7 mm. The synovial sheath of the long head of the biceps tendon was thickened in 10 shoulders of patients with amyloidosis and in one normal shoulder. The subacromial-subdeltoid bursa was thickened in seven shoulders of patients with amyloidosis but not in any shoulders in the control group. Eight shoulder sonograms from dialysis patients showed intra- or periarticular nodules. CONCLUSION: Sonographic findings associated with amyloidosis of the shoulder include thickening of the rotator cuff, the synovial sheath of the long head of the biceps tendon, and the subacromial-subdeltoid bursa and the presence of nodules within or around the joint. Shoulder sonography may be useful as a noninvasive technique for the diagnosis of dialysis-related amyloidosis in the proper clinical setting.

Bupivicaine arthrography of the post-arthroplasty hip.

Addition of bupivicaine, a medium-length-acting local anesthetic, to the contrast material in arthrography of total hip prostheses provides reliable information as to whether the source of pain is intracapsular or extracapsular. In 12 surgically proven cases, complete relief of pain after bupivicaine injection correctly identified an intracapsular source of pain in 10, with only 1 false-positive and 1 false-negative. These results compare favorably with the results of the contrast arthrograms in these patients in localizing the pain even if a specific diagnosis could not be reached. Bupivicaine as an adjunct to contrast material during arthrography provides additional information useful in management decisions regarding the necessity of revision arthroplasty.