Biomedical subjects

R B Staron

Publications and source records attributed to R B Staron.

At least 37 records · Page 2Linked to original sources

PubMed1996

Fracture after cardiac transplantation: a prospective longitudinal study.

Cardiac transplantation is associated with increased prevalence of vertebral fractures, but the natural history of and risk factors for fracture after this life-saving procedure are unclear. We evaluated 47 patients (34 men and 13 postmenopausal women) before transplantation with spinal radiographs, determination of bone density by dual energy x-ray absorptiometry, and measurement of biochemical indexes of mineral metabolism. During the first year after transplantation, incident fractures were documented radiographically. Associations among demographic characteristics, bone density, biochemistries, and fracture risk were evaluated with logistic regression analysis. Despite supplementation with elemental calcium (1000 mg/day) and vitamin D (400 IU/day), 17 patients (7 women and 10 men) sustained a total of 34 fractures. Most fractures involved the spine, and 85% of the patients who experienced fracture did so within 6 months of transplantation. Fifty-four percent of the women and 29% of the men experienced fracture. Femoral neck bone mineral density was significantly lower in women who experienced fracture than in those who did not (0.604 +/- 0.11 vs. 0.760 +/- 0.12 g/cm2; P < 0.04), but did not differ in men according to fracture outcome. The amount of bone loss at the femoral neck by 6 months after transplantation was significantly greater in men with fracture than in men without fracture (12.0 +/- 6.4% vs. 6.8 +/- 5.3%; P < 0.04), but did not differ in women according to fracture outcome. Pretransplant 1,25-dihydroxyvitamin D levels were significantly lower (25 +/- 9 vs. 39 +/- 17 pg/mL; P < 0.007) and intact PTH levels tended to be higher in men who did not experience fracture (37 +/- 15 vs. 69 +/- 46 pg/mL; P < 0.06). Individual pretransplant bone density measurements demonstrated substantial overlap between patients who did and did not experience fracture, and normal bone density did not necessarily protect against fracture after transplantation. We conclude that fractures are a common and early complication of cardiac transplantation. No pretransplant measurement has yet been identified that reliably predicts fracture after transplantation in the individual patient.

Bone Density↗

PubMed1996

Patellar height on sagittal MR imaging of the knee.

OBJECTIVE: The aim of this study was to determine if the radiographic assessment of patella alta using the patellar tendon:patella ratio can be applied to sagittal MR images of the knee. MATERIALS AND METHODS: Sagittal T1-weighted MR images of 46 knees were reviewed with corresponding radiographs. After lengths of the patella and patellar tendon were measured on the lateral radiographs and on the sagittal mid patellar images, the tendon:patella ratios were calculated. RESULTS: We found the mean tendon:patella ratio on radiographs to be 1.0 +/- 0.2 (SD) and on MR imaging, 1.1 +/- 0.1. These two values were not significantly different (p = .01) and had good-to-excellent correlation (r = .7). We found no statistical difference between the sexes on either radiographs or MR imaging, nor did we find statistical differences on MR imaging between the tendon:patella ratios of straight and wavy patellar tendons. CONCLUSION: As on radiographs, patellar height can be reliably assessed on sagittal MR imaging using the patellar tendon:patella ratio. On sagittal MR imaging, patella alta is suggested at values greater than 1.3 (1.1 + 2 SD).

Adult↗

PubMed1995

The symptomatic accessory tarsal navicular bone: assessment with MR imaging.

PURPOSE: To determine if a symptomatic accessory navicular bone, a normal variant, displays a pattern of altered signal intensity on magnetic resonance (MR) images indicative of an abnormality that could account for the patient's foot pain. MATERIALS AND METHODS: Both feet were imaged in seven patients with an accessory navicular bone on radiographs and unilateral foot pain. Five patients had focal medial foot pain, and two had vague, diffuse pain. T1-weighted spin-echo and T2-weighted fat-suppressed sequences were used. RESULTS: A bone marrow edema pattern (BMEP) was noted in the accessory navicular bones of the five patients with focal pain and in the adjacent navicular tuberosities of three of them. The two patients with vague pain showed no osseous or soft-tissue abnormalities. Two patients with positive MR images underwent surgical excision of the accessory navicular bone, and histologic examination revealed osteonecrosis in one patient. CONCLUSION: The BMEP in a symptomatic accessory navicular bone is indicative of chronic stress and/or osteonecrosis. This information can furnish an objective basis for surgical or conservative management.

Adult↗

PubMed1995

Longitudinal measurements of bone density and biochemical indices in untreated primary hyperparathyroidism.

A large number of patients with primary hyperparathyroidism today do not undergo parathyroidectomy. In this prospective study, we evaluated the effect of untreated disease on biochemical and bone densitometric indices. In 66 patients, seven annual measurements showed no change in serum calcium, phosphorus, PTH, vitamin D, or alkaline phosphatase; in urinary calcium, hydroxyproline or hydroxypyridinium cross-link excretion; or lumbar spine, femoral neck, and radial bone mineral density. The subset of postmenopausal women also showed no change in biochemical indices or bone density at any of the three sites. Twenty-four patients met guidelines for surgery as established by the NIH Consensus Conference, 1990. They differed from those who did not meet these guidelines only by being younger (50 +/- 3 vs. 62 +/- 2 yr; P = 0.0005) and by having higher urinary calcium excretion [7.7 +/- 0.9 vs. 5.4 +/- 0.3 mmol/L (310 +/- 37 vs. 215 +/- 14 mg/g creatinine); P < 0.01]. No longitudinal changes in biochemical profile or bone mineral density at any site were noted in this subgroup. Conservative management of patients with mild primary hyperparathyroidism does not lead to progression of disease, as reflected by biochemical indices. Bone density is maintained over 6 yr of observation at sites reflecting both cortical (radius) and cancellous (lumbar spine) bone.

Adult↗

PubMed1995

Increased bone mineral density after parathyroidectomy in primary hyperparathyroidism.

Skeletal involvement in primary hyperparathyroidism is characterized by preferential loss of cortical bone, whereas cancellous bone is relatively spared. Little data are available concerning changes in bone density, particularly at sites containing more cancellous bone, after successful parathyroidectomy. Most patients with primary hyperparathyroidism are asymptomatic, but approximately 50% meet one or more criteria for surgery. In a prospective study of 34 patients who met one or more such criteria, bone density rose at all skeletal sites (lumbar spine, femoral neck, and the radius) in the 4 yr after surgery. The lumbar spine, with most cancellous bone, showed a rapid (mean +/- SE, yr 1, 8.2 +/- 2.0%; P < 0.005) and sustained (yr 4, 12.8 +/- 2.8%; P < 0.001) rise. Post-menopausal patients were similar (by yr 4, 12.5 +/- 2.7%; P < 0.005). At the femoral neck, with intermediate cancellous and cortical composition, a similar increase was noted (12.7 +/- 3.8% by yr 4; P < 0.01). The distal radius, containing mostly cortical bone, rose modestly (4.0 +/- 1.5% by yr 3; P < 0.05), except in patients with lowest preoperative bone density, where the increase was marked (12.3 +/- 2.6% by yr 3; P < 0.05). In patients meeting surgical guidelines, parathyroidectomy is associated with improved bone mineral density.

Adult↗

PubMed1994

Value of the coronal plane in MRI of internal derangement of the knee.

Sagittal images usually receive the most scrutiny in the magnetic resonance evaluation of meniscal and anterior cruciate ligament tears. We assessed the relative contribution of the coronal view. All knee magnetic resonance examinations performed over a 2-year period that had surgical confirmation were reviewed with respect to the presence of meniscal and anterior cruciate ligament tears. The appearance of an attenuated but uninterrupted anterior cruciate ligament was also evaluated. The coronal and sagittal plane images were evaluated separately. The study included 68 medial menisci, 67 lateral menisci, and 71 anterior cruciate ligaments. The coronal view is especially useful in the evaluation of the lateral meniscus. An anterior cruciate ligament that appears attennated but uninterrupted should be considered intact. The anterior cruciate ligament may be evaluated on the coronal view. The coronal view should be regarded as similar to the lateral chest radiograph, which supplements, but does not replace, the frontal chest radiograph.

Anterior Cruciate Ligament↗

PubMed1994

Magnetic resonance imaging of occult fractures of the proximal femur.

The evaluation of the painful hip in the elderly osteoporotic patient with normal plain radiographs can be difficult. We studied 15 osteopenic patients with normal plain radiographs and suspected hip fractures with magnetic resonance (MR) imaging and found MR to be an excellent aid in detecting occult fractures. A clear fracture was seen in 10 of the 15 patients, who then underwent surgical repair based on the MR study. The remaining patients had no MR-demonstrable fracture and were successfully treated nonoperatively. Some believe that a negative bone scan in this population of patients should be repeated within 3 days prior to a definitive "no fracture" decision being made. Unfortunately, bone scanning lacks spatial resolution, and increased osteoblastic activity may be caused by other pathologic processes besides fracture. Two of the 15 patients had MR-demonstrated bone infarcts near the fracture. One patient also had femoral head osteonecrosis on the side of the fracture. One patient with metastatic prostatic carcinoma had a hip fracture and one patient with metastatic breast carcinoma had no fracture. No only is MR imaging an excellent technique for delineating occult fractures, but due to its spatial resolution, associated bone disorders adjacent to fractures can be detected in most instances. From a cost perspective, rapid diagnosis and early treatment of an occult femoral fracture is advisable. A reduced hospital stay pending diagnosis and the early institution of definitive therapy also decrease the chance that a simple non-displaced fracture will displace and require more complex management with resultant increased morbidity and cost.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Coraco-clavicular joint: normal variant in humans. A radiographic demonstration in the human and non-human primate.

The coraco-clavicular joint is a true synovial joint that may become painful in some patients after trauma. Among the descriptions of this entity is the assertion that the coraco-clavicular joint is routinely seen in gorillas and gibbons. We undertook to assess the incidence of this variant among gorillas, gibbons, and other non-human primates. All available radiographs of large primates performed at the International Wildlife Conservation Park/Bronx Zoo (IWCP) over the past 10 years were reviewed by a musculoskeletal radiologist (human radiology). All radiographs were taken during the normal clinical care of the non-human primate population of the IWCP and are a part of each animal's clinical record. Eighty-one non-human primate radiographs were suitable for study as they contained the region of interest. The 81 radiographic examinations included 14 different species of non-human primates. The coraco-clavicular joint was seen in 4 out of 9 silver-leaf langur, 2 out of 8 lowland gorilla, and in 1 out of 6 white-handed gibbon. In all non-human primate cases where the coraco-clavicular joint occurred, it was bilateral. In 1 out of 8 mandrill, there were very wide distal clavicular ends that articulated both with the coracoid and with the acromion. The coraco-clavicular joint differs from an ossified coraco-clavicular ligament. The radiographic appearance is characteristic and is found in both humans and some non-human primate species. It may rarely become painful following trauma. When symptomatic in humans, resection of this anomalous articulation is curative.

Acromioclavicular Joint↗

PubMed1994

Abnormal geometry of the distal radioulnar joint: MR findings.

Previously developed criteria of normal distal radioulnar joint (DRUJ) axial geometry were applied to routine magnetic resonance (MR) images of 50 wrists. All wrists lacked clinically evident DRUJ instability. An attempt to apply the three geometric criteria to seven of the cases was not possible, since the prescribed landmarks were not visible. The remaining 43 cases were retrospectively divided into a symptomatic group (25 wrists), with clinical abnormalities referable to the ulnar side of the wrist, and an asymptomatic group (18 wrists), with no such abnormalities. Abnormal DRUJ geometry was found in 12 symptomatic and 2 asymptomatic wrists. This difference between the groups is significant (p = 0.02), suggesting that many symptomatic wrists exhibit different DRUJ geometry than is found in most asymptomatic wrists.

Adolescent↗

PubMed1994

O'Donoghue's triad: magnetic resonance imaging evidence.

OBJECTIVE: The objective was to search for magnetic resonance imaging evidence of medial collateral ligament (MCL) injury in knees with proven tears of the anterior cruciate ligament (ACL) and medial meniscus; the three abnormalities that make up O'Donoghue's triad. Although the MCL injury can be unapparent clinically, knee joint stability may be compromised. DESIGN: The superficial portion of the MCL was evaluated on 19 MR studies of 16 knees with arthroscopically proven ACL and medial meniscal tears. MCL thicknesses were compared to those on MR images of 19 normal knees. PATIENTS: The injured knees were of 13 men and 3 women, ranging in age from 19 to 56 years; the normal knees were of 10 men and 9 women, ranging in age from 19 to 55 years. RESULTS AND CONCLUSIONS: The medial collateral ligaments of all injured knees were abnormal, and, as a group, they had greater thicknesses and more intraligamentous thickness variability than normal knees. The MR appearance of both ACL and medial meniscal tears served as indirect evidence of MCL injury, with irregular MCL thickening indicative of prior injury.

Adult↗

PubMed1993

The flipped meniscus sign.

Meniscal fragments may be difficult to detect on magnetic resonance (MR) imaging and yet are clinically significant. This paper describes and illustrates the MR appearance of an easily overlooked meniscal fragment. Ten knees, each appearing to show an abnormally large anterior meniscal horn (8 mm or more in height) were prospectively identified on MR images. In each case demonstrable large tears of the ipsilateral posterior horns were present (same meniscus as had large anterior horns). The lateral meniscus was involved in nine cases and the medial in one. Two of the ten patients imaged had surgically proven bucket-handle meniscal tears as well as meniscal fragments overlying the ipsilateral anterior horn. In one case previous MR imaging at our institution had demonstrated the affected anterior horn to be of normal caliber. The striking MR appearance of an abnormally enlarged anterior meniscal horn in association with a tear of the ipsilateral posterior horn suggests the presence of a meniscal fragment or of a posteriorly detached bucket-handle tear of the posterior horn of the meniscus.

Female↗

PubMed1993

MRI of soft tissue abnormalities: a primary cause of sickle cell crisis.

The early manifestations of sickle cell crisis in soft tissues are important to recognize, though rarely manifest on radiographs and difficult to evaluate on computed tomography and bone scans. Documentation is critical, however, if appropriate judgments as to emergency treatment versus conservative measures are to be made. Seventeen adults seen in the emergency room or hospitalized in presumed sickle cells crisis underwent magnetic resonance imaging within 24-72 h of presentation. Results indicate that magnetic resonance imaging is a sensitive modality for documenting early soft tissue pathology which may be the predominant or sole cause of sickle cell crisis.

Adult↗

PubMed1993

Osteoporosis after cardiac transplantation.

PURPOSE: The purpose of this study was to determine the prevalence of osteopenia and fractures and to describe the biochemical indices of mineral metabolism in patients who have undergone cardiac transplantation. PATIENTS AND METHODS: Forty adult patients who had received a cardiac transplant between 1982 and 1990 and who were receiving immunosuppressive therapy with prednisone and cyclosporine A were studied. Bone densitometric measurements by dual-energy x-ray absorptiometry of the lumbar spine and femoral neck and radiographs of the thoracic and lumbar spine were obtained for all patients. Routine serum and urine biochemical values as well as more specialized biochemical analyses (intact parathyroid hormone, metabolites of vitamin D, and osteocalcin) were obtained. RESULTS: Osteopenia was present in 28% of the patients at the lumbar spine and 20% of the patients at the femoral neck. Vertebral fractures were present in 35% of patients. In contrast to other patients receiving glucocorticoids, serum osteocalcin, a marker of bone formation, was elevated in 60% of patients. CONCLUSIONS: Osteopenia and vertebral fractures are common in patients after cardiac transplantation. The presence of elevated osteocalcin levels suggests that the pathogenesis of the osteoporosis in these patients differs from that of glucocorticoid-induced osteoporosis.

Absorptiometry, Photon↗

PubMed1991

Magnetic resonance imaging of the foot and ankle.

Beginning with its early success in the hip and knee, magnetic resonance has been universally acknowledged as a major advance in musculoskeletal imaging. Subsequent technical improvements encouraged its rapid adaptation for delineating wrist and shoulder joint pathology. In part because of the small, complex curvilinear structures involved, however, the required technology as well as the potential advantages of magnetic resonance imaging in the ankle and foot were realized only recently. This article illustrates some of the clinical applications of magnetic resonance imaging in foot and ankle pathology.

Ankle↗

PubMed1989

Magnetic resonance imaging of para-articular and ectopic ganglia.

This study was undertaken to evaluate the efficacy of magnetic resonance imaging in (1) improving preoperative identification of soft tissue ganglia and in (2) enhancing management by defining their origins, attachments, and extensions. Magnetic resonance images of 17 ganglia were evaluated for intrinsic signal, internal structure, overall shape, and relationship to joints and tendon sheaths using a Philips 0.5 Tesla superconductive magnet with receiver dedicated surface coils. Magnetic resonance imaging proved particularly well suited to delineating soft tissue ganglia and characterizing several of their distinctive diagnostic features which are not optimally imaged by other modalities such as computed tomography and ultrasound.

Adolescent↗

PubMed1986

Computed tomographic volumetric calculation reproducibility.

Previous studies have described computed tomographic (CT) measurement of the total volume of large organs and tumors. This study examines sources of error in the CT volumetric measurement of small anatomic structures, and has potential application to the volumetric measurement of small extravisceral tumors. Volume is determined by multiplying observer measurement of area by the CT slice thickness. We focused on the measurement of small cross-sectional areas as a major source of error in volumetric calculations. One observer made ten area measurements on each of 12 structures of various sizes. For areas larger than 8 to 10 cm2, any single measurement was within 2 to 4% of the mean of ten values. For areas smaller than 8 to 10 cm2, measurements varied more with respect to the mean, and rose approximately exponentially as the measured cross-sectional area approached zero.

Humans↗

PubMedDate not supplied

Surgical sutures: MR artifacts and sequence dependence.

Artifact reduction is fundamental to the daily clinical application of magnetic resonance (MR) imaging. Imaging of the postoperative patient may be difficult because of surgically introduced materials that result in artifacts. The authors tested some commonly used types of surgical suture for MR susceptibility artifact with various imaging sequences. Ten different suture types were studied. Suture was immersed in vegetable oil in separate plastic test tubes. The sutures were also studied embedded in meat. All samples were studied with T1-weighted and T2-weighted spin-echo, STIR (short-inversion-time inversion-recovery), and two-dimensional and three-dimensional gradient-echo sequences. Silk suture produced the most artifact.

Animals↗

PubMedDate not supplied

CT scans through metal scanning technique versus hardware composition.

OBJECTIVE: Streak artifact on CT scans of metal containing areas has been a long standing problem. Although several artifact reducing methods have been used to improve image quality, most have been limited by requiring specialized equipment or lengthy complex calculations that are not automated. Others have shown that increasing the beam energy results in increased thickness of metal that may be imaged by CT without severe image degradation. We have studied the image quality of bone surrounding metal both with titanium and cobalt-chrome prostheses using various scanning techniques. METHODS: In a double blind fashion, 28 radiology residents and attendings were surveyed as to the best technique for imaging bone detail surrounding metal. A series of images was arranged of an implanted titanium prosthesis, a cobalt-chrome prosthesis and a pelvis repaired with stainless steel pelvic reconstruction plates. Scans were performed using three techniques: 120 kVp, 170 mA, 2 s, 360 degrees rotation, 140 kVp, 140 mA, 3 s, 360 degrees rotation, 140 kVp, 140 mA, 4 s, 420 degrees rotation. RESULTS: Titanium was superior to cobalt-chrome (p < .0001 Wilcoxon Signed Rank Test). No advantage was noted for higher kVp or increased scan arc of 420 degrees compared to the standard 360 degrees. CONCLUSION: Titanium allows improved bone detail surround the metal than CT cobalt-chrome. We have found no advantage to using either high kVp or a 420 degrees scan arc to improve the image quality of bone surrounded by metal.

Acetabulum↗