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Biomedical subjects

D Resnick

Publications and source records attributed to D Resnick.

At least 127 records · Page 7Linked to original sources

Insufficiency fracture of the sternum caused by osteopenia: plain film findings in seven patients.

Sternal insufficiency fractures, whether nonbuckling (displaced or nondisplaced) or buckling, are rare and have been described in elderly osteopenic patients with accentuated kyphosis of the thoracic spine. We retrospectively analyzed the radiographs and clinical records in seven osteopenic patients with sternal insufficiency fractures and correlated the type of insufficiency fracture with the presence and degree of dorsal kyphosis, as well as the presence of chest pain, soft-tissue mass, and osteolysis. We found that displaced or nondisplaced nonbuckling fractures (five patients) may be associated with chest pain localized to the sternum (three patients), and may be present with (three patients) or without (two patients) associated thoracic kyphosis. This type of insufficiency fracture also may be accompanied by a soft-tissue mass and osteolysis (three patients), findings simulating pathologic fractures. All buckling insufficiency fractures (two patients) were associated with thoracic kyphosis and were asymptomatic. Our findings suggest that sternal insufficiency fractures may occur with or without exaggerated dorsal kyphosis. The fractures are an uncommon complication of osteopenia and may resemble pathologic fractures when osteolysis and soft-tissue swelling are present.

Adult

Jogging causes acute changes in the knee joint: an MR study in normal volunteers.

As MR imaging allows evaluation of soft-tissue structures not previously possible with imaging techniques, we undertook a preliminary study to evaluate the effects of a popular form of exercise (jogging) on the knee. The specific question prompting our investigation was, does repetitive impulse loading produced by jogging cause acute structural changes within the knee that are visible by MR imaging? The knees of 10 healthy subjects were examined on a 1.5-T MR system before and immediately after 30 min of continuous jogging. The same extremity was examined each time, and the imaging sequences and photographic technique (meniscal windows) were identical for both examinations. Effusions developed in five of 10 subjects after exercise. In addition, five of 10 subjects had subtle increased signal intensity within their menisci. These results suggest that jogging frequently leads to acute changes in the knee that are visible on MR imaging. The significance of these changes is unknown.

Acute Disease

MR imaging of the temporomandibular joint: a cadaver study of the value of coronal images.

Recent studies comparing cryosectional anatomy of the temporomandibular joint (TMJ) to its MR appearance have shown that the assessment of disk displacement is inaccurate when based on the sagittal plane alone. This article describes the MR appearance of the normal and abnormal (positional and osseous changes) TMJ in the coronal plane and compares these findings with their cryosectional anatomy. Twenty-two TMJs from unselected frozen cadavers were embedded in paraffin. Coronal and sagittal MR imaging was performed; specimens were then cut in the same plane as the coronal images. Disk position by cryosection was normal in 14 cases and abnormal in eight cases. Coronal MR images alone correctly depicted the TMJ disk position in 17 cases (77%) (13 normal, four abnormal). Complementary sagittal images were necessary for diagnosing anterior displacement in two cases (9%). MR was inaccurate in three cases (14%) of severe degenerative joint disease. Bone condition was correctly diagnosed on the basis of coronal images alone in all cases. Our study shows that coronal MR imaging alone of the TMJ in cadavers accurately shows disk position in 77% of cases. Complementary sagittal images were of benefit in the diagnosis of an additional 9% with anterior displacement. Disk position was assessed inaccurately in either plane in patients with severe degenerative joint disease. For a full MR assessment of the TMJ for disk position and bone condition, we recommend imaging in both coronal and sagittal planes.

Cadaver

MR arthrography of the shoulder: comparison with conventional MR imaging.

Twenty-three patients underwent both conventional MR imaging of the shoulder and MR shoulder arthrography for clinically suspected labral or rotator cuff abnormalities. Images obtained before and after contrast administration were studied independently, and without knowledge of clinical findings, by two radiologists for the presence of abnormalities of the glenoid labrum or rotator cuff. Results were correlated with surgical findings in all patients. Nine patients had surgically proved labral tears. MR arthrography detected all nine labral abnormalities, while six of the nine were missed on conventional MR imaging. Fourteen patients had surgically proved rotator cuff tears. MR arthrography detected 11 of the 14 tears and missed three partial tears on the bursal surface. Conventional MR imaging detected nine cuff tears and missed five tears; two of these were complete rotator cuff tears and three were partial tears of the undersurface of the rotator cuff. Our results suggest that MR arthrography enhances the accuracy of MR in the evaluation of the glenoid labrum and rotator cuff tendon.

Adolescent

Magnetic resonance imaging of the shoulder.

MR imaging has proved to be of great value in the assessment of musculoskeletal imaging. Its superiority in evaluating knee and spine pathology is well established. Recent studies also have established an important role for MR imaging in the assessment of shoulder disorders. Multiplanar capabilities coupled with excellent contrast resolution that allows simultaneous delineation of osseous and soft-tissue structures make MR imaging a useful method for evaluating the complex anatomy of the shoulder.

Humans

Pseudopseudarthrosis in a patient with ankylosing spondylitis.

There is a growing consensus that the mechanism leading to extensive discovertebral destruction (type III) in most patients with ankylosing spondylitis relates to fracture and subsequent pseudarthrosis. We introduced the term "pseudopseudarthrosis" to describe (in our case) the occurrence of abnormal motion between 2 fused spinal segments, resulting in extensive discovertebral destruction without fracture or pseudarthrosis.

Adult

Magnetic resonance imaging of the knee.

MRI has been in widespread clinical use since 1985 and in this short time has dramatically altered musculoskeletal imaging. The technology continues to become increasingly sophisticated; as both clinicians and radiologists become more familiar with its possibilities, further elucidation of pathologic processes affecting the knee will occur. In addition, advanced computer software has allowed a decrease in imaging time, which will allow a decrease in cost of this once-expensive technique. At this time, in many centers, MRI has essentially replaced arthrography for evaluation of disorders of the knee. The advantages of MRI include its inherent contrast sensitivity that allows visualization of a wide variety of tissues, multiplanar capabilities, lack of ionizing radiation, noninvasiveness, rapidity of imaging, and acceptability to patients.

Bone Marrow

Innovative approaches to noninvasive bone densitometry.

In conclusion, this review has endeavored to familiarize the practicing radiologist with some of the newer approaches to noninvasive bone densitometry that are currently being explored as potential improvements over existing techniques. Three-dimensional volumetric CT is a practical means of measuring bone density in the proximal femur, owing to the widespread availability of the necessary scanning equipment, and affords enhanced prediction of biomechanical parameters in the spine and hip, but suffers from limitations similar to those of conventional quantitative CT. Dual-energy projection radiography offers significant potential advantages over dual-photon absorptiometry from the standpoint of precision, radiation dose, image quality, and examination time, but remains to be thoroughly tested. Compton scattering appears to be a viable alternative to single-photon absorptiometry for bone density determinations in the peripheral skeleton. Neutron and proton activation analysis are unlikely to achieve widespread application, owing to their cyclotron-dependent nature, although the former will probably remain the optimal means for determining total body calcium. Experience with scanning-slit fluorography and magnetic resonance as applied to noninvasive bone densitometry is currently too limited to permit prediction of their ultimate role in this respect. As a final point, it should be noted that major incentives for mobilization of bone densitometric equipment currently exist: on Earth, as a means of facilitating patient access and saving money via joint ventures, and in space for monitoring the adverse effects of weightlessness on skeletal mass and the ability to function following return to a gravity environment.

Bone Density

Current and innovative methods for noninvasive bone densitometry.

This article summarizes a variety of noninvasive techniques for measuring bone density in the clinical setting. Although dual-energy x-ray absorptiometry and quantitative computed tomography are currently the most widely used methods, older techniques such as radiogrammetry and single-photon absorptiometry continue to have research applications, and experimental approaches such as compton scattering and proton activation analysis may be important in the future. The evaluation of bone mass measurement underscores continuing progress in our understanding of bone metabolism and biomechanics, and has provided valuable insight into improvements in the therapy of osteoporosis and other forms of metabolic bone disease.

Absorptiometry, Photon

Advanced imaging of the wrist.

Abnormalities of the wrist present a difficult diagnostic challenge requiring thorough evaluation of both osseous and soft-tissue structures. Advanced techniques such as scintigraphy, computed tomography, three-phase arthrography, and, most recently, magnetic resonance imaging have added greatly to our understanding of wrist pathology. This article discusses the application of these techniques in imaging the wrist.

Arthrography

Computed tomography of rheumatologic disorders.

Diseases of the spine and peripheral joints can be diagnosed noninvasively by this revolutionary imaging modality. CT has retrospectively demonstrated superiority over myelography and other imaging techniques in delineating various pathologic conditions--e.g., trauma, neoplasm, and infection--as well as arthropathy. Specific technical approaches are described in detail.

Age Factors

Inflammatory disorders of the vertebral column: seronegative spondyloarthropathies, adult-onset rheumatoid arthritis, and juvenile chronic arthritis.

A variety of inflammatory disorders may involve the spine and sacroiliac joint. Of these, the seronegative spondyloarthropathies (consisting principally of ankylosing spondylitis, psoriasis, Reiter's syndrome, and certain intestinal diseases), adult-onset rheumatoid arthritis, and juvenile chronic arthritis are particularly important. The imaging abnormalities accompanying these disorders, supplemented with some clinical and pathologic data, are the subject of this review.

Arthritis, Juvenile

Quantitative dual-energy radiographic absorptiometry of the lumbar spine: in vivo comparison with dual-photon absorptiometry.

Quantitative dual-energy radiographic absorptiometry (DRA) and dual-photon absorptiometry (DPA) were compared to determine the best means of assessing bone density. Both methods were used to evaluate the lumbar spine in 107 women (aged 35-84 years [mean, 64 years]) referred for evaluation of osteoporosis risk. High correlation was documented between measurements derived by the two techniques, with a .95 linear regression coefficient for the total spine density measurement. Age-related regression equations were similar in slope but manifested different intercepts. Bone mineral density values derived with DRA were consistently lower than those obtained with DPA (conversion equation: DPA density = [1.067 X DRA density] + 0.163). Besides the inherent imperfections of each system, it was found that inaccurate identification of intervertebral spaces on the low-resolution DPA images introduced errors in patient data. DRA may replace DPA as the dedicated projectional densitometric procedure of choice for technical reasons, but at present a conversion equation must be used to compare DRA data to DPA data.

Adult

Axial bone density in rheumatoid arthritis: comparison of dual-energy projection radiography and dual-photon absorptiometry.

The usefulness of dual-energy projection radiography (DEPR) in the evaluation of rheumatoid arthritis was compared with that of dual-photon absorptiometry (DPA). Bone density measurements of the lumbar spine and the proximal femur were obtained with DPA in 75 patients (45 women and 30 men). For comparison, the bone density of the lumbar spine was measured with DEPR in a subset of 52 patients (33 women and 19 men). High correlation was documented between DEPR and DPA measurements of the lumbar spine. No significant relationship between bone density and age was observed, in contrast to the known relationship in healthy subjects regardless of sex, site of measurement, or measurement technique. Bone density values in the spine and the proximal femur were significantly reduced for both sexes as compared with matched normative data. Interlevel variation in lumbar vertebral density as measured with DEPR was not significantly different in patients with rheumatoid arthritis as compared with control subjects. Significant correlation between bone density determination and body weight, as well as duration of menopause, was noted, whereas duration of disease, functional status, and cumulative corticosteroid dose were not predictive. Rheumatoid arthritis did not appear to influence the relationship between DEPR and DPA measurements of the spine, and neither method nor site of measurement exhibited a consistent advantage in discriminating patients with rheumatoid arthritis from healthy control subjects.

Absorptiometry, Photon

Osteosclerosis of the phalanges in Werner syndrome.

Werner syndrome is an autosomal-recessive disease characterized by premature aging, shortness of stature, scleroderma-like skin changes, endocrine abnormalities, and cataracts. Although radiographic findings have been well documented, the presence of distinctive osteosclerotic changes in the phalanges of the hands and feet has not been emphasized in previous publications. The authors' review of radiographs of both hands in nine patients and of both feet in six patients with Werner syndrome documented the frequent occurrence of phalangeal sclerosis related predominantly to endosteal thickening. In the hand, sclerosis was present in every patient, was generally symmetric in distribution, predominated in the distal phalanges, and demonstrated an ulnar predilection. Similar changes in the phalanges of the feet were demonstrated in only two patients. The presence of osteosclerosis in the phalanges of the hand alone or both the hand and foot, when combined with osteoporosis and periarticular calcification, suggests the diagnosis of Werner syndrome.

Adult

Diffuse idiopathic skeletal hyperostosis: diagnostic significance of radiographic abnormalities of the pelvis.

Retrospective evaluation of the osseous pelvis in 93 patients with severe diffuse idiopathic skeletal hyperostosis (DISH) revealed 14 locations of radiographic abnormalities. Two osteoradiologists independently studied these sites for abnormalities in a prospective, blinded fashion in 103 patients over the age of 45 years. Lateral radiographs of the thoracolumbar spine were quantitatively and qualitatively evaluated to determine whether DISH, spondylosis deformans, or a normal spine was present. Statistical analysis was performed for evaluation of interobserver reliability, the relationship between pelvic and spinal abnormalities, and the significance and predictive values of pelvic abnormalities for DISH versus non-DISH and DISH versus spondylosis deformans. Although significantly higher frequencies and greater extents of radiographic abnormalities at 10 of 14 pelvic locations were noted for DISH compared with non-DISH, this number decreased to four of 14 locations when compared with spondylosis deformans. The alterations in three of these four pelvic sites consisted of ossification of ligaments. These changes appear to be good indicators of the presence of spinal DISH and support the concept that DISH is an entity separate from spondylosis deformans.

Adult