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Biomedical subjects

D Resnick

Publications and source records attributed to D Resnick.

At least 343 records · Page 19Linked to original sources

Destructive noninfectious spondyloarthropathy in hemodialysis patients: a report of four cases.

A rapidly progressive destructive spondyloarthropathy that resembles infectious spondylitis is reported in four patients undergoing long-term hemodialysis for chronic renal disease. Its characteristics are similar to those of a recently recognized entity reported in ten patients in the rheumatology literature. It is believed that the alterations represent a crystal-induced arthropathy because these crystals are known to cause destructive arthropathy in extra-spinal sites, the association of crystal deposits and chronic renal disease in patients undergoing dialysis is well recognized, and calcium hydroxyapatite and calcium pyrophosphate have been recovered from biopsy material in two of the reported 14 cases. Patients with chronic renal disease in whom a rapidly destructive spinal arthropathy develops should have a biopsy of the affected area to exclude infection. Because a crystal-induced destructive process may simulate infection, crystalline analysis should also be performed on the biopsy material.

Female↗

Focal fat deposition in axial bone marrow: MR characteristics.

One hundred fifty-eight magnetic resonance (MR) imaging studies of the spine were reviewed to assess the frequency and distribution of focal deposits with signal behavior typical of fat in the axial bone marrow. In addition, three fresh cadaveric spines were evaluated with MR imaging and subsequently sectioned for anatomic and histologic correlation. Macroscopic evaluation of the sectioned cadaveric specimens revealed well-defined, yellow areas within the bone marrow that correlated precisely with localized zones of signal intensity characteristic of fat on MR images. Histologic evaluation of these regions demonstrated typical focal fatty replacement of hematopoietic bone marrow. Their appearance was related to age and the presence of pathologic changes such as spondylitis, kyphoscoliosis, and spondylosis. Based upon these observations, focal fatty replacement of hematopoietic bone marrow appears to be a common phenomenon that should not be confused with localized disease processes.

Adipose Tissue↗

MR arthrography: anatomic-pathologic investigation.

To enhance the efficacy of magnetic resonance (MR) imaging in evaluating articular soft-tissue structures, arthrography was performed before imaging 45 fresh cadaveric specimens. Contrast agents used were gadolinium-DTPA, 0.9% saline, diatrizoate, and air. MR imaging was performed with and without intraarticular contrast material, and specimens were subsequently sectioned in the same plane. Gd-DTPA was the most effective agent. Saline and diatrizoate exhibited equivalent signal behavior and necessitated T2-weighted sequences, while air was not useful. Depiction of normal anatomy was enhanced with MR arthrography. After surgical creation of lesions in selected specimens, subtle tears were delineated exclusively with MR arthrography, and major tears were diagnosed more confidently. Intraarticular contrast material may enhance the diagnostic capabilities of MR imaging in the setting of joint disease.

Air↗

Osteoarthritis of the facet joints: accuracy of oblique radiographic assessment.

Sensitivity and specificity of lumbar spine radiography in the assessment of facet joint osteoarthritis were evaluated, with computed tomography (CT) as the standard. Two independent radiologists used a four-point scale to blindly grade facet joint osteoarthritis on oblique radiographs and transaxial CT scans obtained within an 8-month period in 50 consecutive patients with pain in the lower back. The L-3 to L-4, L-4 to L-5, and L-5 to S-1 facet joints were evaluated, and 68% appeared abnormal on CT scans, with 28% exhibiting moderate or severe disease. Interobserver agreement was high for conventional radiography (perfect agreement in 57% and agreement to within one grade in 39%) and still higher for CT (perfect in 63% and to within one grade in 35%). Receiver operating characteristic curve analysis indicated that oblique radiography was most accurate (55% sensitivity, 69% specificity) in distinguishing the presence from the absence of disease; in distinguishing absent or mild from moderate or severe disease, the specificity of oblique radiography was higher, at 94%, but its sensitivity was much lower, at 23%. Conventional radiography is a useful technique in screening for facet joint osteoarthritis but is insensitive compared with CT.

Adult↗

Vertebral mineral status: assessment with single- versus multi-section CT.

A volumetric approach to quantitative single-energy computed tomography (CT) of the spine for trabecular bone evaluation was compared with the accepted single-section method in 32 thoracic and lumbar vertebral bodies from six cadaveric specimens. Both 5-mm and 10-mm contiguous section sequences afforded greater sample volumes, mean mineral equivalent values, and precision than did the single midplane section technique. These findings can be explained by inhomogeneous trabecular distribution, differential bone resorption rates for various cancellous regions, and nonuniform deposition of marrow fat. Scoliosis may modify the net influence of these factors owing to altered biomechanical forces. Although the single-section method affords optimal sensitivity to early or subtle alterations in vertebral trabecular bone density, it may misrepresent the status of the total cancellous volume. Because three-dimensional histographic analysis includes structurally important peripheral trabeculae in determinations of mean mineral equivalent values, it may more accurately reflect vertebral body strength and risk of compression fracture.

Biomechanical Phenomena↗

Carpal alterations in adult-onset Still disease, juvenile chronic arthritis, and adult-onset rheumatoid arthritis: comparative study.

A specific pattern of pericapitate involvement of the wrist has been described in the rheumatologic literature as characteristic of adult-onset Still disease (AOSD), a relatively rare disorder that is often diagnosed by exclusion after extensive and frequently invasive tests. To evaluate the potential diagnostic value of carpal radiography in suspected cases of AOSD, a retrospective blinded analysis of 48 patients (16 each with AOSD, juvenile chronic arthritis, and adult-onset rheumatoid arthritis) was performed. Pericapitate articular alterations without radiocarpal involvement were found to be distinctly unusual among patients with rheumatoid arthritis but frequent in the setting of AOSD. In juvenile chronic arthritis severe pericapitate involvement also occurs frequently but is more likely to be associated with interosseous fusion and severe pancompartmental disease.

Adult↗

Pictorial review: cross-sectional imaging of the foot and ankle.

Cross-sectional imaging techniques are becoming increasingly important for the evaluation of foot and ankle disorders. Computed tomography affords superior depiction of osseous anatomy, and is useful in the assessment of acute fractures, degenerative joint disease, and post-operative alterations. Magnetic resonance imaging is particularly well suited to soft tissue disease, including neoplasms, tendinitis, myopathy, and infection, owing to its excellent contrast discrimination capabilities.

Ankle Joint↗

Periostitis in hypertrophic osteoarthropathy: relationship to disease duration.

The relationship of periostitis to disease duration in primary hypertrophic osteoarthropathy and the association of periostitis with cardiopulmonary disorders (secondary type) were studied in order to define distinguishing features between the two. Radiographic skeletal surveys were performed in 24 patients with hypertrophic osteoarthropathy to analyze pattern (single layer, multilayered, irregular) and site of involvement (diaphysis, metaphysis, epiphysis). The six patients with primary hypertrophic osteoarthropathy and the 11 patients with cyanotic congenital heart disease had thicker, more widespread periostitis involving the diaphysis, metaphysis, and epiphysis, in contrast to abnormalities in the seven patients with hypertrophic osteoarthropathy secondary to carcinoma of the lung. Average cortical bone widths as determined by radiogrammetric measurement of the second metacarpals were significantly greater for the patients with primary hypertrophic osteoarthropathy (8.9 +/- 6.0 mm) and cyanotic congenital heart disease (8.5 +/- 6.4 mm) as compared with the patients with bronchogenic carcinoma (6.0 +/- 3.9 mm). Correlation of radiographic patterns with duration of disease confirms that thicker, more extensive alterations are indicative of long-standing disease. The periostitis of hypertrophic osteoarthropathy is therefore not dependent on the primary or secondary nature of the disease but principally on its duration.

Adolescent↗

Patterns of paravertebral ossification in the prehistoric saber-toothed cat.

In cases of paravertebral ossification in humans, the radiographic characteristics usually lead to a specific diagnosis. Similar manifestations are sometimes described in other species. We applied knowledge of the radiographic appearance of spinal alterations in modern humans to the evaluation of 48 fused thoracic and lumbar fossilized spine specimens from the prehistoric saber-toothed cat (Smilodon californicus), in which prominent paravertebral ossification is frequently found. Inspection, conventional radiography, and, in some cases, CT and fluoride analyses were performed. The spinal alterations in the saber-toothed cat, which previously were believed to be caused primarily by trauma, showed characteristics of three major pathologic processes: trauma, diffuse idiopathic skeletal hyperostosis, and inflammatory disease of a type similar to ankylosing spondylitis. The last two categories have rarely been diagnosed in species other than humans. The results suggest that diffuse idiopathic skeletal hyperostosis and inflammatory spondyloarthropathy are diseases that occurred in prehistoric times and are not confined to the human species.

Animals↗

Articular cartilage defects: detectability in cadaver knees with MR.

The capability of 1.5-T MR imaging to detect focal defects in articular cartilage was investigated with cadaveric knees with and without intraarticular injection of saline and gadolinium-DTPA (Gd-DTPA). Full-thickness cartilage lesions ranging in diameter from 1 to 5 mm were surgically created in the femoral articular surfaces. Images were acquired with a variety of pulse techniques, slice thicknesses, and interslice gaps as well as one or two signal excitations. Potential intraarticular contrast agents (saline and Gd-DTPA) were tested, and their signal behaviors compared with that of hyaline cartilage. All cartilage defects were occult on T1-weighted and balanced images without Gd-DTPA. The smallest defect identified by using intraarticular saline was 3 mm in diameter and was apparent only on T2-weighted images. Intraarticular Gd-DTPA afforded detection of defects as small as 2 mm, even with short imaging times. Signal-intensity differences between saline and articular cartilage were minimal on T1-weighted images and increased on T2-weighted images; intensity differences were high between Gd-DTPA and articular cartilage on all imaging sequences. These results indicate that intraarticular fluid and appropriate selection of imaging sequences are necessary for delineation of focal defects in articular cartilage. They also show that Gd-DTPA is the optimal contrast agent for this purpose.

Cadaver↗

Symptomatic intraspinal synovial cysts: opacification and treatment by percutaneous injection.

Intraspinal synovial cysts are usually located in the lower lumbar spine in association with osteoarthritis of the facet joints, and they are most accurately diagnosed by using CT. Surgical removal of intraspinal synovial cysts implicated in the development of radiculopathy has resulted in symptomatic relief. A nonoperative method of treatment consists of CT-guided needle placement into the facet joint adjacent to the cyst, followed by injection of contrast material to show communication between the joint and the cyst and injection of corticosteroids. Three outpatients were treated in this fashion without complications. Complete relief of symptoms was achieved in two cases and partial relief was achieved in one. Follow-up CT scans performed 2 months after the procedure showed no change in the size of the cysts in two of the patients. A 6-month follow-up CT scan in the third patient, however, showed significant improvement in cyst size. These preliminary results suggest that this procedure is an alternative to surgical management of intraspinal synovial cysts.

Humans↗

Potential contrast agents for MR arthrography: in vitro evaluation and practical observations.

In an attempt to identify an ideal contrast agent for MR arthrography, signal behavior as well as T1 and T2 values for articular cartilage, menisci, and ligaments were determined in knees from cadavers and normal volunteers. Comparison was made with similar data derived for intraarticular blood, varying concentrations of an albumin-saline solution (simulating synovial fluid) and Gd-DTPA, 0.9% saline, Renografin 60%, and air. Cadaveric specimens were imaged after intraarticular administration of each substance. A 500-microM volume of Gd-DTPA proved to be an ideal contrast agent for MR arthrography, exhibiting excellent contrast differences with articular structures on T1-weighted images. An albumin concentration of 12%, potentially occurring in severe inflammatory arthritis, also manifested adequate contrast to articular cartilage on T1-weighted images. Renografin and saline provided inadequate contrast on T1-weighted images, and saline necessitated the use of T2-weighted sequences. Air was not found to be an optimal contrast agent. Intraarticular blood exhibited insufficient contrast differences with articular cartilage during the acute hemorrhagic phase. Synovial fluid associated with severe arthritis as compared with fresh intraarticular hemorrhage may thus prove to be a better biological contrast agent for MR arthrography. Saline is currently recommended for use in arthrography, but Gd-DTPA offers significant advantages and should be safety-tested for potential clinical use.

Air↗

Stress fractures of the distal tibia and calcaneus subsequent to acute fractures of the tibia and fibula.

Stress fractures (two in the calcaneus and four in the distal tibia) occurring distal to the site of a healing fracture of the tibia or fibula were discovered in five patients. Three of these fractures were identified radiographically at the time of their occurrence, and three were identified only after retrospective review of the radiographs of 74 patients with previous tibial or fibular fractures. Three of the patients were less than 10 years old. All five patients had disuse osteopenia and recently had begun weight-bearing. Four patients had healing of their acute fractures with angulation or displacement. Stress fractures can easily be overlooked on radiographic studies in this setting and may be a source of pain that mistakenly can be attributed to malunion or nonunion. Stress fractures should be considered in patients with fractures of the lower extremity, particularly those who experience new or persistent pain or discomfort.

Adolescent↗

Radiographic evaluation of joints resurfaced with osteochondral shell allografts.

The radiographic features of 41 cadaveric osteochondral shell (low ratio of subchondral bone to articular cartilage) allografts placed in 24 patients for articular resurfacing as an alternative to arthroplasty are presented. Underlying causes of joint disease included ischemic necrosis (20 grafts), osteochondritis dissecans (nine), chondromalacia patellae (10), and posttraumatic osteochondral fracture with degenerative disease (two). Congruity with the adjacent native articular surface and the opposite side of the joint was evident on immediate postoperative radiographs in all patients, and proved to be critical to the ultimate success of the procedure. On follow-up radiographs over a period of 2-28 months, successful incorporation of the allograft was characterized by progressive loss of the relative increased density of the graft, in association with diminished lucency related to new bone formation at the graft-native bone interface, as well as maintained alignment. Graft failure was associated with positional changes including collapse, persistent increased density, and poorly defined fragmentation that occasionally simulated infection radiographically and resulted in intraarticular bodies. Resurfacing of diseased articulations with osteochondral shell allografts constitutes a potentially desirable alternative to total joint arthroplasty, particularly among younger patients. Consequently, an awareness of the expected radiographic alterations associated with graft incorporation and failure is important.

Adolescent↗

Enteropathic arthropathies.

Musculoskeletal disease occurs in association with inflammatory bowel disorders including Crohn's disease and ulcerative colitis, as well as with Whipple's disease; with enteritis caused by Salmonella, Shigella, and Yersinia; and also following intestinal bypass surgery. Extraintestinal causes of musculoskeletal alterations include Laennec's and biliary cirrhosis and pancreatitis. Three types of musculoskeletal abnormalities are recognized in patients with inflammatory bowel diseases: peripheral joint arthritis, sacroiliitis and spondylitis identical to ankylosing spondylitis, and rarely, miscellaneous changes such as digital clubbing and hypertrophic osteoarthropathy.

Arthritis, Infectious↗

Magnetic resonance imaging of the lumbar spinous processes and adjacent soft tissues: normal and pathologic appearances.

The spinous processes and intervening soft tissues of the lumbar region may be involved by degenerative, inflammatory, neoplastic, and traumatic processes resulting in low back pain. While conventional radiography and computed tomography have proven useful in the demonstration of abnormalities affecting the spinous processes, they are of limited utility in the evaluation of the intervening soft tissues, which are the predominant site of initial pathologic involvement. To explore the potential role of magnetic resonance imaging (MRI) in the assessment of the spinous processes and adjacent ligaments, a retrospective review of 55 consecutive examinations of the lumbar spine was performed. The normal and pathologic appearances of the region on both T1 and T2 weighted images were characterized, and the optimal imaging variables for demonstration of the spinous processes and adjacent soft tissues were determined with subsequent prospective application to new cases. Correlative examination of cadaveric sections and dried specimens was also performed to facilitate understanding of anatomical relationships visualized by MRI. Based upon the results of this investigation, MRI is the procedure of choice in the evaluation of disease processes affecting the spinous processes and intervening ligaments, primarily owing to the ability to image directly in the sagittal plane and its superior soft tissue contrast discrimination capability.

Adolescent↗