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Biomedical subjects

K A Buckwalter

Publications and source records attributed to K A Buckwalter.

At least 37 records · Page 2Linked to original sources
PubMed1994

Langerhans cell histiocytosis of bone: MR imaging.

Magnetic resonance (MR) images of 12 pathologically proven lesions of Langerhans cell histiocytosis (LCH) of bone were reviewed retrospectively. MR identified all lesions, three of which were not identified on plain radiographs. In all cases, MR showed greater abnormality than did plain radiographs. With one exception, all lesions were hypointense on T1-weighted images and hyperintense on T2-weighted images. The lesions and associated soft tissue abnormalities were very conspicuous on short TI inversion sequences and T1-weighted post-contrast images. Follow-up MR studies in two patients after chemotherapy showed decreased size and enhancement of lesions compared with baseline studies.

Adolescent↗
PubMed1994

Case report 873: Lipoma arborescens (villous lipomatous proliferation of the synovial membrane).

A case of lipoma arborescens with typical features was presented. MR imaging established the preoperative diagnosis by visualizing the typical frond-like synovial projections containing fatty tissue. The extent of joint involvement must be fully documented because an open synovectomy is most appropriate in the management of this disease. Although lipoma arborescens is a rare condition, it is important to recognize the MR features due to the large volume of MR examinations of the knee which are performed.

Aged↗
PubMed1994

Comparison of mammography, sonography, and magnetic resonance imaging in the detection of silicone-gel breast implant rupture.

Silicone-gel breast implant rupture is difficult to diagnose preoperatively. A variety of radiological methods have been used for diagnosis. This study prospectively compares film-screen mammography, high-resolution sonography, and magnetic resonance imaging in the diagnosis of implant rupture using predetermined diagnostic criteria. Thirteen patients (24 implants) underwent film-screen mammography, sonography, and magnetic resonance imaging to evaluate the integrity of their implants. All patients subsequently underwent surgical removal of the implants. Preoperatively, the integrity of each implant was rated on a three-level classification system on the basis of one modality by a reviewer who was unaware of the results of the other two modalities. The three imaging modalities achieved the following sensitivities and specificities, respectively: mammography, 69% and 82%; sonography, 54% and 64%; MRI, 69% and 55%. Even though each modality addresses some of the limitations of the others, in this group of patients, there was no clearly superior imaging tool.

Adult↗
PubMed1994

Occult dorsal carpal ganglion: comparison of US and MR imaging.

PURPOSE: To evaluate the usefulness of ultrasound (US) and magnetic resonance (MR) imaging in patients suspected of having an occult dorsal carpal ganglion. MATERIALS AND METHODS: The authors prospectively studied US and MR images of 14 wrists in 13 consecutive patients suspected of having an occult dorsal carpal ganglion. RESULTS: Eleven dorsal carpal ganglia were identified with US and nine with MR imaging. One patient refused the MR imaging study. Of two equivocal cases at MR imaging, one was a ganglion and another was a compressible capsular recess, as determined at US. One ganglion was missed with both techniques. The average diameter of the ganglion cysts was 4.9 mm. CONCLUSION: MR imaging and US are equally effective in the detection of occult dorsal carpal ganglia. Because of its dynamic capabilities and lower cost, US should be the initial imaging procedure for suspected occult dorsal carpal ganglia.

Adult↗
PubMed1993

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.

Cartilage↗
PubMed1993

MR imaging of meniscal tears: narrow versus conventional window width photography.

Narrow window width photography of magnetic resonance (MR) images of knee menisci is promoted as a useful tool in the detection of meniscal tears. To assess the diagnostic efficacy of this method, conventional and narrow window width MR images of 48 patients (96 menisci, 37 tears) were interpreted by two experienced observers. Images were graded on a five-point scale to enable receiver operating characteristic (ROC) curve analysis. The ROC curves constructed from the conventional window width interpretations were similar to those of the narrow window width interpretations for both observers. It was not possible to prove that the areas under the two curves were significantly different. This suggests that there is no globally significant improvement in the detection of meniscal tears when narrow window width images are used for interpretation.

Adolescent↗
PubMed1993

Carpal instability in rheumatoid arthritis.

The authors examined prospectively the prevalence of and relations among patterns of carpal instability in 52 patients with proven rheumatoid arthritis. Posteroanterior, lateral and oblique radiographs of both wrists were obtained. Nineteen patients exhibited one or more patterns of instability. The most common isolated pattern was volar intercalated segmental instability, apparent in six patients. Five patients showed more than one pattern, most commonly a combination of ulnar translocation and volar carpal subluxation. Patients with active erosions or changes in the distal radioulnar joint were more likely to exhibit instability than those without such findings. Carpal instability is a frequent mechanical complication of rheumatoid arthritis. The radiologist should be aware of this possibility, so that a diagnosis can be made promptly and appropriate clinical management begun.

Arthritis, Rheumatoid↗
PubMed1992

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.

Anterior Cruciate Ligament↗
PubMed1992

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.

Bone and Bones↗
PubMed1991

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.

Adult↗
PubMed1990

Radiographically guided fine-needle aspiration of nonpalpable breast lesions.

Radiographically guided fine-needle aspiration (X-FNA) in 215 nonpalpable, mammographically detected breast lesions was performed by means of a coordinate-grid localization system. Aspirates were categorized either into four cytologic groups or as simple cysts. Based on the most stringent cytologic criteria, the maximum sensitivity for detection of carcinoma was 97% and the specificity was 94%. However, according to these strict cytologic criteria, only 46% of aspirates contained representative material. Based on less stringent cytologic criteria, the maximum sensitivity was 68% and the specificity was 97%. Forty-one of 74 lesions proved to be malignant at biopsy. Thirty-four patients did not complete adequate mammographic follow-up. High sensitivity and specificity can be achieved with X-FNA. However, management decisions ultimately require integration of mammographic findings with cytologic results. Close cooperation among mammographer, surgeon, cytopathologist, and patient is mandatory for successful results.

Biopsy, Needle↗
PubMed1990

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.

Humans↗
PubMed1989

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.

Adult↗
PubMed1989

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.

Carpal Bones↗
PubMed1987

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.

Adult↗