Biomedical subjects
Publications and source records attributed to Mikayel Grigoryan.
Calcifications in idiopathic calcinosis cutis are most commonly localized to one area. We herein report a 66-year-old woman with idiopathic calcinosis cutis who unusually exhibited widespread calcific deposits. In this report, we will also briefly discuss the pathogenesis, differential diagnosis, and current treatment of this disease.
Older black men have higher adjusted bone mineral density (BMD) and a lower adjusted rate of decline in hip BMD than older white men. There are few published data on the prevalence of morphometric vertebral fractures in older white men and no published data for older black men. The study's objective was to estimate the prevalence of vertebral fractures in older men and explore differences in prevalence between older white and black men. Subjects included five hundred forty-two men (415 white and 127 black) aged 65 and above (mean age of 74.0+/-5.7 years) participating in the longitudinal component of the Baltimore Men's Osteoporosis Study. Radiographs of the thoracic and lumbar spine were obtained using standard protocols and read for the presence of vertebral deformities using binary semiquantitative techniques. Quantitative morphometry was performed and vertebral fractures were defined using the Melton-Eastell method. BMD was measured at the femoral neck, total hip and lumbar spine. Participants also completed self- and interviewer-administered questionnaires and underwent standardized clinical examinations. One or more vertebral fractures were present in 30 of 514 men with available radiographs: estimated prevalence 5.8% (95% confidence intervals [CI]: 4.0, 8.3%). Prevalence was significantly higher in white than black men, 7.3% vs 0.9% (Fishers' exact p =0.01): age-adjusted odds ratio=8.3 (95% CI: 1.1, 62.5). Among white men, there was no significant difference in age-adjusted femoral neck or total hip BMD or frequency or severity of back pain between men with and without vertebral fractures. In conclusion, older white men have a higher prevalence of vertebral fractures than older black men. This may be related to differences in BMD between these groups.
OBJECTIVE: To determine the relationship between radiographic progression of joint space narrowing and cartilage loss on magnetic resonance imaging (MRI) in patients with symptomatic knee osteoarthritis (OA), and to investigate the location of MRI-based cartilage loss in the knee and its relation to radiographic progression. METHODS: Two hundred twenty-four men and women (mean age 66 years) were studied. Radiographs and MRI of the more symptomatic knee were obtained at baseline and at 15- and 30-month followup. Radiographs of the knee (with weight-bearing) were read for joint space narrowing (scale 0-3), with progression defined as any worsening in score. We used a semiquantitative method to score cartilage morphology in all 5 regions of the tibiofemoral joint, and defined cartilage loss as an increase in score (scale 0-4) at any region. We examined the relationship between progression of joint space narrowing on radiographic images and cartilage loss on MRI, using a generalized estimating equation proportional odds logistic regression, adjusted for baseline cartilage score, age, body mass index, and sex. The medial and lateral compartments were analyzed separately. RESULTS: In the medial compartment, 104 knees (46%) had cartilage loss detected by MRI. The adjusted odds ratio was 3.7 (95% confidence interval 2.2-6.3) for radiographic progression being predictive of cartilage loss on MRI. However, there was still a substantial proportion of knees (80 of 189 [42%]) with cartilage loss visible on MRI when no radiographic progression was apparent. Cartilage loss occurred frequently in the central regions of the femur and tibia as well as the posterior femur region, but radiographic progression was less likely to be observed when posterior femur regions showed cartilage loss. Radiographic progression appeared specific (91%) but not sensitive (23%) for cartilage loss. Overall findings were similar for the lateral compartment. CONCLUSION: While our results provide longitudinal evidence that radiographic progression of joint space narrowing is predictive of cartilage loss assessed on MRI, radiography is not a sensitive measure, and if used alone, will miss a substantial proportion of knees with cartilage loss.
Seronegative spondyloarthropathies comprise a group of inflammatory arthritides, which consists of ankylosing spondylitis, psoriatic arthritis, reactive arthritis (Reiter's syndrome), enteropathic arthritis, and undifferentiated spondyloarthropathy. All of them share common laboratory, clinical, and imaging findings, with characteristic involvement of the sacroiliac joints, spine, and, to various degrees, peripheral joints. For many years, conventional radiography was the mainstay for definitive diagnosis of sacroiliitis and for follow-up of the anatomic changes in the spine, peripheral joints, and entheses. Conventional radiographs remain the imaging investigation of choice; however, they are unable to detect early inflammatory changes of sacroiliitis, which are important for establishing a diagnosis without delay. Other imaging modalities, such as computed tomography, bone scintigraphy, magnetic resonance imaging, and ultrasonography have improved the capabilities of detecting early disease and became useful adjuncts to plain films. In addition, they also have enabled more accurate detection of pathology at various anatomic sites of the musculoskeletal system predominantly involved in spondyloarthropathies. This article will review and highlight the role of each of these modalities in the assessment of the axial and peripheral skeleton in seronegative spondyloarthropathies.
Currently, there are no in vivo techniques for quantifying healing within fractures involving mainly trabecular bone. Methods for quantitatively assessing healing would aid the investigation of new treatment regimes, and might also be useful for predicting whether a patient may be undergoing delayed union. Using CT and automated image registration, we have developed an image processing technique for measuring changes in CT image intensity at fracture sites. The technique focuses on quantifying the formation of new mineralised tissue within fracture gaps, while ignoring loss of bone mineral due to disuse osteoporosis. Seven patients with fractures of the distal radius were examined for 12 weeks following fracture. To assess reproducibility of measurements of change in CT intensity at the fracture line, measurements were performed on two separate occasions, by each of two independent readers. Reproducibility was compared to rates of change over time, to determine detectable differences in individual progression. Scans were scored qualitatively for features of healing and scores compared to the quantitative measurements. The mean (SD) change in CT intensity was +128 (65) Hounsfield Units (HU) over the 12 week follow-up. Inter- and intra-observer reproducibilities were both similar (+/- 17 HU), 1/7 of the change seen during the study. In this small patient cohort, a significant increase in CT intensity was seen 2 weeks post-fracture. Large early increases in CT intensity were associated with early visual appearance of sclerosis and blurring of the fracture line. In this preliminary, prospective study, we have developed a reproducible quantitative technique for measuring changes in CT intensity of trabecular bone at the fracture line in the distal radius. Further work is required to determine whether it can be used to identify, or monitor patients who are undergoing delayed fracture repair. The technique appears sensitive for measuring changes immediately post-fracture, and could have a role in examining potential effects of new therapies in patient cohorts.
Vertebral fractures are the hallmark of osteoporosis, and occur with a higher incidence earlier in life than any other type of osteoporotic fractures. It has been shown that both symptomatic and asymptomatic vertebral fractures are associated with increased morbidity and mortality. Morbidity associated with these fractures includes decreased physical function and social isolation, which have a significant impact on the patient's overall quality of life. Since the majority of vertebral fractures do not come to clinical attention, radiographic diagnosis is considered to be the best way to identify and confirm the presence of osteoporotic vertebral fractures in clinical practice. Traditionally, conventional lateral radiographs of the thoracolumbar spine have been visually evaluated by radiologists or clinicians to identify vertebral fractures. The two most widely used methods to determine the severity of such fractures in clinical research are the semiquantitative assessment of vertebral deformities, which is based on visual evaluation, and the quantitative approach, which is based on different morphometric criteria. In our practice for osteoporosis evaluation we use the Genant semiquantitative approach: an accurate and reproducible method tested and applied in many clinical studies. The newest generation of fan-beam DXA systems delivering "high-resolution" lateral spine images offers a potential practical alternative to radiographs for clinical vertebral fracture analysis. The advantages of using DXA over conventional radiographic devices are its minimal radiation exposure and high-speed image acquisition. It also allows combined evaluation of vertebral fracture status and bone mass density, which could become a standard for patient evaluation in osteoporosis. The disadvantage of DXA use is that upper thoracic vertebrae cannot be evaluated in a substantial number of patients due to poor imaging quality. We truly believe that the that there is a major role for radiologists and clinicians alike to carefully assess and diagnose vertebral fractures using standardized grading schemes such as the one outlined in this review. Quantitative morphometry is useful in the context of epidemiological studies and clinical drug trials; however, the studies would be flawed if quantitative morphometry were to be performed in isolation without additional adjudication by a trained and highly experienced radiologist or clinician.
RATIONALE AND OBJECTIVES: Development of new agents to induce fracture healing requires more sensitive methods to detect early changes in fracture repair. The aims of this study were to determine quantitative and qualitative features of fracture healing using volumetric computed tomography (CT) and to compare them with conventional radiography during the weeks following uncomplicated fractures of the appendicular skeleton. MATERIALS AND METHODS: 39 otherwise healthy men and women with acute, closed fractures of the distal radius, tibial and/or fibular malleoli, or tibial shaft, were enrolled and underwent CT and X-ray imaging at 1, 2, 4, 8, 12, and 16 (tibial shaft only) weeks post fracture. Qualitative assessment included fracture line/margins, fracture gap, external callus appearance, callus-to-cortex ratio, bridging, and radiologic union. Quantitative assessment of CT density changes (Hounsfield units [HU]) in the fracture gap was performed in a subset of 8 fracture patients using MEDx multimodality image analysis software (Sterling,VA). The analysis was performed by drawing free form regions of interest (ROI) covering the fracture gap on baseline (week 1) images and by automated registration of the follow-up images to the baseline co-ordinate system. RESULTS: The mean time to achieve radiologic union on CT was slightly shorter than on X-rays for radial and tibial shaft fractures (7.3 vs. 8.0 weeks, P = .1). Blurring of the fracture margins and reactive sclerosis were the earliest signs of healing in both modalities. External callus formation was evident in 11 cases and was detected earlier with CT technique. Overall, CT images allowed for more complete and detailed visualization of healing compared with conventional X-rays, which were limited by cast and fixation hardware superimposition, especially in subjects with malleolar and distal radial fractures. Quantitative evaluation showed good intraobserver and interobserver reproducibility and a statistically significant correlation to qualitative changes. CONCLUSION: Our methods of fracture healing assessment are reliable tools that are able to detect early changes in normal bone healing and may serve as useful additions to subjective image analysis in monitoring fracture healing in clinical trials. CT shows some advantages over conventional X-rays in evaluation of early fracture healing.