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.

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.

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.

MRI in osteoarthritis of the hip: gradations of severity.

In a prospective study, 10 patients with well-documented osteoarthritis (O.A.) of the hips were imaged using spin-echo pulse sequences (TR = 0.5 to 1.5 s and TE = 28 to 60 ms). After analyzing the changes observed, an MR grading system for assessing severity of O.A. in the hips was developed. Using this grading system and an established grading system for osteoarthritis using roentgenograms (both systems use grades 0-4), two radiologists independently graded the MR studies and plain films separately, twice. The roentgenogram grading system was more accurate in predicting symptoms in the more severe cases, whereas the MR grading system was slightly more useful in the less severe cases. Our results show that MR can demonstrate a spectrum of changes of O.A. in the hips. Its ability to directly image articular cartilage makes it a powerful research and clinical tool.

Visualization of myocardial infarction and subsequent coronary reperfusion with MRI using a dog model.

Twelve anesthetized mongrel dogs underwent left thoracotomy with placement of a removable ligature around the left circumflex coronary artery. Following a 3 to 6 hour delay, ECG-gated spin-echo MRI was performed. The ligature was then removed reperfusing the heart, and after a 10-15 min period, MRI repeated. Finally, post-sacrifice images were obtained, and the hearts chemically stained for infarct evaluation. The MR images were subjectively and quantitatively evaluated for visibility of the endocardial border and of the injured myocardium, and for changes after reperfusion. The injured tissue was variably visible in vivo, the major limitation a result of motion blurring and artifact. The abnormal tissue was easily visible on MRI in 11 animals, and not clearly visible in one. The endocardial border was easily seen in 10 animals. The variation of calculated relaxation times was high for both normal and ischemic/infarcted myocardium in the beating hearts (normal: T1 = 566 +/- 288, T2 = 38 +/- 6; injured myocardium: T1 = 637 +/- 250, T2 = 41 +/- 12) in contrast, relatively stationary skeletal muscle measured in the same images had narrower ranges (T1 = 532 +/- 199, T2 = 28 +/- 2). Changes with reperfusion were seen, but not reliably. The infarcted or ischemic zones were easily visible on post-sacrifice images in all animals imaged. Post-sacrifice relaxation times were T1 = 564 +/- 69 msec, T2 = 39 +/- 3 msec for normal heart muscle, and 725 +/- 114, T2 = 47 +/- 5 for ischemic/infarcted tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of spiral (helical) computerized tomography with three-dimensional reconstruction in pediatric solid tumors.

The ability to accurately assess tumor size and orientation to surrounding vital structures is an important consideration during preoperative evaluation. The authors report on nine children with solid tumors (hepatoblastoma [1], neuroblastoma [2], adrenal cortical carcinoma [2], liver adenoma [1], primitive neuroectodermal tumor [PNET] [1], and stage V Wilms' tumor [2]) for whom tumor resectability was questioned because of the tumors' close proximity to major blood vessels (noted through conventional radiographic imaging). The children had scanning with spiral volumetric acquisition computerized tomography, (CT) which obtains images during continuous rotation of the x-ray source while the patient moves at a constant velocity through the gantry. This technique is rapid (18 to 30 seconds), and is similar with respect to radiation exposure; little or no sedation is required, and the contrast dose is lower than that of conventional CT. Three-dimensional reconstruction of spiral CT imaging provided useful information that allowed successful resection in all nine cases. The authors suggest that spiral CT may become an important imaging modality in the preoperative evaluation of pediatric solid tumors and that further evaluation of this new methodology is warranted.

Evaluation of joint disease in the adult hand and wrist.

The radiographic evaluation of joint diseases in the adult hand and wrist is described in this chapter. The main focus is on the interpretation of plain radiographs of the hands and wrists in patients with joint symptoms. After considering the general approach to the analysis of the radiographs, the findings of the common forms of arthritis are illustrated and the differential diagnoses are discussed.

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.

Imaging in osteoarthritis and crystal deposition diseases.

The challenge in imaging joints and articular cartilage is to detect both early and subtle changes that may influence the treatment of osteoarthritis and crystal deposition diseases. Although radiographs show gross changes, they cannot show cartilage surfaces directly. Both ultrasonography and magnetic resonance imaging are able to demonstrate both the surface and internal details of articular cartilage. Advances in magnetic resonance imaging have begun to show internal details of articular cartilage that correspond with histologic zones. These changes can be shown using minor modifications of conventional imaging techniques. More elaborate studies using experimental contrast agents and sodium nuclear magnetic resonance imaging have shown changes in the magnetic resonance signal intensity that appear to correlate with the distribution of proteoglycans in the cartilage matrix. The application of these techniques may be possible in a clinical setting to enhance the detection and monitor the changes of degenerative joint disease.

Digital skeletal radiography.

Skeletal radiography accounts for a large proportion of the plain film images generated in most radiology departments, yet it has been underemphasized in the investigation of digital imaging technologies. Unique features of skeletal radiography provide a challenge in the evaluation and investigation of digital skeletal imaging. This review summarizes the results of ongoing research in digital skeletal radiography. Elementary concepts of digital imaging are reviewed to provide a foundation for discussion of nominal contrast and resolution requirements for clinically useful digital skeletal radiography. Methods of acquiring digital skeletal images are reviewed, and digital image display, image compression, and basic image processing techniques are discussed with emphasis on specific skeletal applications.

Anterior cruciate ligament: oblique sagittal MR imaging.

Optimal visualization of the anterior cruciate ligament with magnetic resonance imaging requires oblique sagittal imaging planes. Between 10 degrees and 20 degrees of external rotation of the knee is considered ideal. While the knee may normally assume this amount of obliquity in the relaxed position, the orientation of the imaging plane is not guaranteed. Many imagers can perform oblique sagittal imaging, but the operator must set the proper degree of obliquity for the examination. A simple template was devised to facilitate this process, resulting in more consistently oriented imaging planes. The template can be reproduced by photocopying the diagram provided onto a transparency.

Magnetic resonance imaging of the collateral ligaments of the thumb.

Injury to the ulnar collateral ligament of the metacarpal phalangeal joint of the thumb can usually be diagnosed on the basis of a combination of history, radiographic examination, and clinical stress testing of the joint when appropriate. Occasionally, when the patient is seen late and the diagnosis is doubtful, stress evaluation may be ill-advised because a nondisplaced ligament may be displaced in the process. We had recent experience with three patients in whom the use of magnetic resonance imaging was helpful in diagnosing a displaced ulnar collateral ligament in two cases, and an intraligamentous injury in the other. These studies were conducted at no charge to the patient as part of institutional investigational research. The current cost of this technology is prohibitive for routine use; however, when it becomes less expensive, it may be helpful as a diagnostic tool.

Bolus dynamic computed tomography in the evaluation of pulmonary sequestration.

Three cases of pulmonary sequestration evaluated by bolus dynamic computed tomography are described. The computed tomography appearance and the differential diagnosis are discussed. It is important to recognize the advantages of the bolus dynamic technique in the evaluation of pulmonary sequestration as it may eliminate the need for further studies.

The prevalence and significance of cyst-like changes at the cruciate ligament attachments in the knee.

Approximately 1% of the total population referred for magnetic resonance imaging (MRI) of the knee at our facility have cystic changes at or near the attachment of the anterior or posterior cruciate ligaments (ACL, PCL). Cases were collected prospectively from a group of 1710 consecutive knee MR examinations, and a retrospective study analyzed the typical appearance of these cysts and any associated findings. Although most of the cysts were an incidental finding, two were associated with significant adjacent marrow edema.

Direct coronal CT of the scaphoid bone.

A simple technique is described for the acquisition of coronal computed tomographic images of the wrist without positioning or immobilizing devices. The technique was used in four cases in which the radiographs were equivocal, to assess healing after scaphoid bone fracture or grafting. The greater resolution of the images provided more definitive information about healing.

Case report 824: Tuberculosis presenting as a soft tissue forearm mass in a patient with a negative tuberculin skin test.

Tuberculosis presenting as a soft tissue mass is rare. The diagnosis should be considered in patients with radiographic findings of massive soft tissue swelling and cortical bone destruction. Such patients may present with few clinical findings and have no evidence of prior exposure to tuberculosis or history of immunosuppression. Computed tomography may be of use in distinguishing infection from malignancy.

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.