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Biomedical subjects

D Resnick

Publications and source records attributed to D Resnick.

At least 361 records · Page 20Linked to original sources
PubMed1987

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↗
PubMed1987

Radiography of the hyperextended lumbar spine: an effective technique for the demonstration of discal vacuum phenomena.

A prospective evaluation of dynamic lateral lumbar spine radiographs in the erect position in 52 symptomatic patients over the age of 50 years revealed vacuum phenomena in intervertebral discs in 46%. Their frequency was greatest at the L5-S1 spinal level and decreased progressively at higher lumbar levels. Analysis of the dependency of discal vacuum phenomena on spinal position during radiography revealed that hyperextension detected all such phenomena; radiography in the neutral position detected 73% of vacuum phenomena, whereas that obtained with the spine flexed revealed 20% of vacuum phenomena. Our results indicate that lateral radiographs of the hyperextended lumbar spine are useful in the differential diagnosis of intervertebral osteochondrosis (degenerative disease of the nucleus pulposus) and infection.

Aged↗
PubMed1987

Computed tomography of the spine: an update and review.

Computed tomography (CT) has proven to be an important diagnostic imaging technique for the evaluation of a variety of spinal disorders. The method is useful for identifying and characterizing acute fractures in traumatized patients and can accurately quantify spinal canal encroachment. Intervertebral disc disease and facet joint osteoarthritis are readily demonstrated by CT in both the cervical and lumbar regions. The technique can reliably distinguish between infection and neoplastic disease in the spine and is helpful for the guidance of percutaneous biopsy. A variety of congenital and developmental vertebral abnormalities, including dysraphic states, spondylolysis, and spinal stenosis, are optimally assessed using CT. Quantitative CT affords selective analysis of trabecular bone in the spine and has proven useful for the detection and follow-up of osteoporosis as well as other forms of metabolic bone disease. Most recently, the application of multiplanar reformation and three-dimensional image reconstruction has enhanced presentation of diagnostic information contained on cross-sectional images.

Humans↗
PubMed1987

New concepts in bone grafting.

The authors review the diagnostic and surgical imaging aspects of a number of recent bone grafting procedures in the orthopaedic management of various osseous and articular disorders. They discuss several innovative new approaches to bone grafting as well as the use of a variety of bone grafting substitute materials. They discuss the three types of bone graft available for orthopaedic reconstruction; autograft, allograft or homograft and xenograft or heterograft. They stress that an awareness of the radiographic features of each of the various bone grafting techniques is important to the physician dealing with musculoskeletal disorders in determining the results of his efforts.

Bone Transplantation↗
PubMed1987

The architecture of the proximal femur: an imaging analysis.

The proximal femur is a dynamic region whose internal architecture reflects the biomechanical demands of weight-bearing. It is composed of two major trabecular systems arranged along the lines of compressive and tensile stresses. Adaptive alterations in these trabeculae occur in a variety of disorders, including osteoporosis, osteoarthritis, and ischemic necrosis. Plain film radiography and computed tomography (CT) have been utilized to study these changes and provide insight into the pathophysiology of these disorders. Analysis of the order of resorption of trabeculae in osteoporosis, the proliferation of trabeculae in osteoarthritis, and the reparative changes in ischemic necrosis often allows accurate assessment of the severity of involvement and can give valuable information to aid treatment planning.

Femoral Neck Fractures↗
PubMed1987

Knee dysfunction secondary to dislocation of the fabella.

The fabella, a sesamoid bone in the lateral head of the gastrocnemius muscle occurring in 10% to 30% of individuals, is rarely considered a possible cause of knee dysfunction. When noted, the fabella is occasionally mistaken radiographically for an intraarticular ossified fragment; however, symptomatic conditions of the fabella have been well documented in the literature. This is a report of symptomatic dislocation of an enlarged fabella in a 37-year-old man. In a review of the literature of various lesions of the fabella, disability related to dislocation seems not to have been previously reported.

Adult↗
PubMed1987

The diabetic foot.

Disorders of the foot are a common and disabling problem among diabetic patients. Often the most difficult problem radiographically is to differentiate infection from neuropathic change. This article reviews the radiographic features and imaging approach to patients with diabetic foot disorders, with specific reference to both conventional and advanced imaging modalities.

Angiography↗
PubMed1986

Distal interphalangeal joint involvement in rheumatoid arthritis.

Sixty-two patients with seropositive rheumatoid arthritis (RA) were evaluated radiographically for distal interphalangeal (DIP) joint involvement and were compared with 50 age- and sex-matched control subjects. The frequency of DIP erosions was 37% in the patients versus 14% in the controls; these erosions were mild and were not related to disease duration. Erosions elsewhere in the hand and wrist were of all degrees of severity and were related in part to disease duration. Osteophytes occurred frequently in both the RA group (71%) and the control group (60%). However, joint space narrowing occurred more frequently in RA patients (77%) than in the controls (46%) (P less than 0.009). The findings from this study suggest that in RA patients, DIP erosions occur frequently, do not occur in isolation, and are not simply a marker for severe global erosive disease in the hand and wrist. The high frequency of osteophytosis and joint space narrowing in both groups probably represents the overlap of osteoarthritis and RA that occurs in many patients.

Arthritis, Rheumatoid↗
PubMed1986

Computerized tomography of proximal femoral trabecular patterns.

A comprehensive imaging and pathologic investigation utilizing patients and cadaver material was performed in order to identify the normal trabecular pattern of the proximal femur and to assess alterations in this pattern in various disorders. Patients and specimens were studied with computed tomography (CT), including three-dimensional CT image reconstruction in selected cases and plain film radiography. The CT imaging of the proximal femur provides insight into the dynamic state of bone in this region. Despite limited resolution, three-dimensional CT image reconstruction is capable of portraying the concentration and orientation of major trabeculae in the proximal femur. Increased trabecular spacing occurs in osteoporosis and is well depicted by CT. Proliferation and thickening of the most superior subchondral primary compressive trabeculae is an early sign of osteoarthritis. In the region of the calcar femorale, crossing trabeculae, similar to the appearance of an enchondroma or bone infarct, have been described in osteoporosis and osteoarthritis and probably represent unmasking of normally present reinforcing trabeculae. In ischemic necrosis, CT should be considered a useful modality for detection of early or mild alterations and may be valuable in treatment planning.

Cadaver↗
PubMed1986

Coralline hydroxyapatite bone graft substitutes in a canine metaphyseal defect model: radiographic-biomechanical correlation.

Radiographic and biomechanical assessment of a new type of bone graft substitute derived from reef-building sea coral was performed in a canine metaphyseal defect model. Blocks of this material and autogenous iliac crest graft were implanted, respectively, into the right and left proximal tibial metaphyses of eight dogs. Qualitative and quantitative radiographic evaluation was performed in the immediate postoperative period and at 6 months after surgery. Biomechanical testing was carried out on all grafts following harvest at 6 months, as well as on nonimplanted coralline hydroxyapatite and autogenous iliac cancellous bone. In contrast to autografts, incorporation of coralline implants was characterized by predictable osseous growth and apposition with preservation of intrinsic architecture. Greater percent increase in radiographic density, higher ultimate compressive strength, and lower stiffness with incorporation were documented advantages of coralline hydroxyapatite over autogenous graft. Densitometric measurements correlated moderately with strength for both types of graft material (r = -0.65). These promising results have important implications to the clinical application of coralline hydroxyapatite bone graft substitutes as an alternative to autogenous grafting.

Absorptiometry, Photon↗
PubMed1986

Coralline hydroxyapatite bone graft substitutes in a canine diaphyseal defect model: radiographic features of failed and successful union.

Radiographic and densitometric evaluation of a new type of bone graft substitute derived from reef-building sea coral via a hydrothermal chemical exchange process was undertaken in a canine diaphyseal defect model. Comparably sized blocks of this material and autogenous iliac cortical-cancellous graft were implanted into the respective radial diaphyses of seven dogs. Qualitative and quantitative radiographic assessment was performed during the immediate postoperative period and at 3 months following surgery. Significant complications were observed radiographically in over half of the coralline implanted limbs, including failed union, graft fracture, and loosening of internal fixation hardware. No significant difference was noted in degree of native osseous in-growth between the implants and the autografts, and the latter exhibited a higher success rate. Radiographic film densitometry was found not to be reliably predictive of coralline implant behavior in the individual case. It is concluded that coralline hydroxyapatite bone graft substitutes appear to offer no particular advantage over autogenous grafts in the management of diaphyseal defects, although further investigation is warranted since other factors may be responsible for the unfavorable findings in this study.

Absorptiometry, Photon↗
PubMed1986

High-resolution magnetic resonance imaging of the ankle: normal anatomy.

An imaging-anatomic correlative study of ankle anatomy based upon six healthy adults and six fresh cadaveric specimens was performed to evaluate the diagnostic capabilities of magnetic resonance imaging (MRI). Optimal pulsing sequences and imaging planes for various structures of interest were established. MRI afforded exquisite depiction of anatomic detail, particularly the diagnostically important collateral ligaments. Limitations in the ability to delineate the joint capsule and articular cartilage were documented, with the former detectable only on T2 weighted images in the presence of synovial fluid.

Adult↗
PubMed1986

Fatigue fracture of the distal part of the radius in a pool player.

A stress fracture of the radius occurred in a 22-year-old pool player who was well known for his unique style of putting 'English' on the billiard ball. Typical radiographic findings were seen, and the fracture subsequently healed. Only a few cases of stress fracture of the radius have been previously reported.

Adult↗