Bone microarchitecture assessment by high-resolution peripheral quantitative computed tomography in patients with systemic lupus erythematosus taking corticosteroids

OBJECTIVE

We assessed the relationship between vertebral fracture and bone microarchitecture in patients with systemic lupus erythematosus (SLE) on chronic corticosteroid therapy using high-resolution peripheral quantitative computed tomography (HR-pQCT).

METHODS

Fifty-nine Chinese women with SLE taking corticosteroid were selected to participate in a cross-sectional study. Vertebral fracture was confirmed semiquantitatively by lateral radiographs of the thoracic and lumbar spine. Density and microarchitecture at the distal radius were measured with HR-pQCT. Areal bone mineral density (aBMD) at hip and lumbar spine was measured by dual-energy X-ray absorptiometry (DEXA).

RESULTS

Twelve patients had vertebral fractures. The aBMD of spine or hip did not differ between those with and without vertebral fractures. Measures by HR-pQCT revealed that patients with vertebral fractures had significantly lower level of average bone density (p = 0.007), cortical bone density (p = 0.029), trabecular bone density (p = 0.024), trabecular bone volume to tissue volume (p = 0.023), and trabecular thickness (p = 0.011) than those without vertebral fractures. Independent explanatory variables associated with higher risk of vertebral fractures were older age (p = 0.013) and lower average cortical bone density (p = 0.029).

CONCLUSION

Vertebral fracture in patients with SLE on chronic corticosteroid treatment was associated with alterations of bone density and microarchitectures measured by HR-pQCT and DEXA. However, alterations were more pronounced in measurements by HR-pQCT. Low cortical bone density and old age were significant predictors of vertebral fracture risk.

Vertebral fracture

Vertebral fractures are usually the first to occur in osteoporosis, provide indisputable evidence of reduced bone strength, and are frequently a harbinger of further vertebral and nonvertebral fracture. Radiologists are best placed to draw attention to the presence of vertebral fractures, most of which are clinically silent. Magnetic resonance imaging supplemented if necessary by computed tomography is usually sufficient to enable distinction between osteoporotic and non-osteoporotic vertebral fracture, without a need for percutaneous biopsy.

Durable mesenchymal stem cell labelling by using polyhedral superparamagnetic iron oxide nanoparticles

Small polyhedral superparamagnetic iron oxide (SPIO) nanoparticles (<10 nm) coated with a thin layer of silica were prepared (SPIO@SiO(2) and SPIO@SiO(2)-NH(2)). Surface modification of the small polyhedral silica-coated SPIO nanoparticles with amines led to substantially higher mesenchymal stem cell (MSC) labelling efficiency without the use of additional transfecting agents. Therefore, amine surface-modified nanoparticles (SPIO@ SiO(2)-NH(2)) appeared to be the preferred candidate for MSC labelling. In vitro studies demonstrated that controlled labelling of SPIO@SiO(2) and SPIO@SiO(2)-NH(2) did not cause MSC death or proliferation inhibition. MSCs labelled with SPIO@SiO(2)-NH(2) nanoparticles retained differentiation potential and showed osteogenic, adipogenic and chondrogenic differentiations. The noncytotoxic polyhedral SPIO@SiO(2)-NH(2) nanoparticle-labelled MSCs were successfully implanted in rabbit brain and erector spinae muscle, and demonstrated long-lasting, durable MRI labelling efficacy after 8-12 weeks.

Non-invasive MRI assessment of the articular cartilage in clinical studies and experimental settings

Attrition and eventual loss of articular cartilage are important elements in the pathophysiology of osteoarthritis (OA). Preventing the breakdown of cartilage is believed to be critical to preserve the functional integrity of a joint. Chondral injuries are also common in the knee joint, and many patients benefit from cartilage repair. Magnetic resonance imaging (MRI) and advanced digital post-processing techniques have opened possibilities for in vivo analysis of cartilage morphology, structure, and function in healthy and diseased knee joints. Techniques of semi-quantitative scoring of human knee cartilage pathology and quantitative assessment of human cartilage have been developed. Cartilage thickness and volume have been quantified in humans as well as in small animals. MRI detected cartilage loss has been shown to be more sensitive than radiographs detecting joint space narrowing. It is possible to longitudinally study knee cartilage morphology with enough accuracy to follow the disease-caused changes and also evaluate the therapeutic effects of chondro-protective drugs. There are also several MRI methods that may allow evaluation of the glycosaminoglycan matrix or collagen network of articular cartilage, and may be more sensitive for the detection of early changes. The clinical relevance of these methods is being validated. With the development of new therapies for OA and cartilage injury, MR images will play an important role in the diagnosis, staging, and evaluation of the effectiveness of these therapies.

Proximal femur bone marrow blood perfusion indices are reduced in hypertensive rats: a dynamic contrast-enhanced MRI study

PURPOSE

To investigate the differences in proximal femoral bone marrow blood perfusion indices between hypertensive and normotensive rats using perfusion magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Six-month-old male spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) were used (12 of each). Dynamic contrast-enhanced MRI of the right hip was performed after bolus injection of Gd-DOTA administered through a tail vein cannula. In all, 800 images were acquired at 0.6 sec/image. Regions of interest (ROIs) were drawn comprising the medullary component of proximal femoral shaft and femoral head. MRI maximum enhancement (E(max)) and enhancement slope (E(slope)) were analyzed.

RESULTS

The E(max) and E(slope) of proximal femoral shaft and femoral head of SHR were significantly lower than those of WKY (E(max): 107.4 +/- 18.2% vs. 130.6 +/- 21.5%, P = 0.009, and 76.0 +/- 12.5% vs. 97.9 +/- 6.9%, P < 0.001, respectively; E(slope): 3.01 +/- 0.63%/sec vs. 3.75 +/- 0.74%/sec, P = 0.016, and 1.95 +/- 0.33%/sec vs. 2.28 +/- 0.28%/sec, P = 0.012, respectively). The E(max) and E(slope) of femoral head were significantly lower than those of proximal femoral shaft in both SHR and WKY (P < 0.001). In both SHR and WKY, proximal femoral shaft and femoral head had a rather different contrast enhancement pattern.

CONCLUSION

Proximal femoral shaft and femoral head bone marrow blood perfusion indices were significantly lower in hypertensive rats than in normotensive rats. Femoral head bone marrow was less perfused than proximal femoral shaft in both rats.

Covalently linked immunomagnetic separation/adenosine triphosphate technique (Cov-IMS/ATP) enables rapid, in-field detection and quantification of Escherichia coli and Enterococcus spp. in freshwater and marine environments

AIMS

Developing a rapid method for detection of faecal pollution is among the critical goals set forth by the Environmental Protection Agency in its revision of water quality criteria. The purpose of this study is to devise and test covalently linked antibody-bead complexes for faecal indicator bacteria (FIB), specifically Escherichia coli or Enterococcus spp., in measuring water quality in freshwater and marine systems.

METHODS AND RESULTS

Covalently linked complexes were 58-89% more robust than antibody-bead complexes used in previous studies. Freshwater and marine water samples analysed using covalently linked immunomagnetic separation/adenosine triphosphate quantification technique (Cov-IMS/ATP) and culture-based methods yielded good correlations for E. coli (R = 0·87) and Enterococcus spp. (R = 0·94), with method detection limits below EPA recreational water quality health standards for single standard exceedances (E. coli- 38 cells per 100 ml; Enterococcus spp. - 25 cells per 100 ml). Cov-IMS/ATP correctly classified 87% of E. coli and 94% of Enterococcus spp. samples based on these water quality standards. Cov-IMS/ATP was also used as a field method to rapidly distinguish differential loading of E. coli between two stream channels to their confluence.

CONCLUSIONS

Cov-IMS/ATP is a robust, in-field detection method for determining water quality of both fresh and marine water systems as well as differential loading of FIB from two converging channels.

SIGNIFICANCE AND IMPACT OF THE STUDY

To our knowledge, this is the first work to present a viable rapid, in-field assay for measuring FIB concentrations in marine water environments. Cov-IMS/ATP is a potential alternative detection method, particularly in areas with limited laboratory support and resources, because of its increased economy and portability.

Reduced bone perfusion in proximal femur of subjects with decreased bone mineral density preferentially affects the femoral neck

Using dynamic contrast enhanced MR imaging, this study investigated perfusion of the proximal femur in subjects with normal BMD, low bone mass and osteoporosis. Study cohort comprised healthy elderly Hong Kong Chinese volunteers consisting of 107 males (74.4+/-4.2 years, mean+/-SD) and 135 females (73.9+/-4.3 years). Right proximal femur BMD measurement by DXA and MR perfusion imaging (maximum enhancement, E(max) and enhancement slope, E(slope)) of the femoral head, neck, and proximal shaft were carried out within a one month interval. Normal BMD, low bone mass and osteoporotic subjects accounted for 46.7%, 44.9%, and 8.4% of males; and 32.6%, 43.7%, and 23.7% of females. Perfusion indices showed that femoral head perfusion was less perfused compared to the femoral shaft (E(max) and E(slope) indices of head region=28% of shaft region). Compared with normal BMD subjects, E(max) of femoral head, neck, and proximal femur shaft were reduced by 15+/-5% (mean+/-standard error); 40+/-4%; 15+/-5% respectively for low bone mass subjects, and 36+/-4%; 50+/-6%; 47+/-6% respectively for osteoporotic subjects. E(slope) of femoral head, neck, and proximal femur shaft were reduced by 17+/-7%; 41+/-5%; 4+/-7% for low bone mass subjects and 50+/-5%, 62+/-5%, 34+/-8% for osteoporotic subjects. In low bone mass and osteoporotic subjects there was a tendency for perfusion in the femoral neck to reduce to a greater degree relative to that in the femoral head and shaft.

Reproducibility of MR perfusion and (1)H spectroscopy of bone marrow

PURPOSE

To determine the reproducibility of proton ((1)H) magnetic resonance (MR) spectroscopy and dynamic contrast-enhanced MR imaging in a clinical setting for the assessment of marrow fat fraction and marrow perfusion in longitudinal studies.

MATERIALS AND METHODS

In all, 36 subjects (17 females, 19 males, mean age 72.9 +/- 2.9 years) who underwent MR spectroscopy and/or dynamic contrast-enhanced perfusion imaging of the proximal femur were asked to return after 1 week for a repeat MR examination.

RESULTS

Reproducibility of (1)H MR spectroscopy in all bone areas tested was high, ranging from 0.78-0.85, with the highest reproducibility being in the femoral head and lowest in the femoral neck. Reproducibility of paired perfusion measurements ranged from 0.59 (enhancement slope femoral head) to 0.98 (enhancement maximum acetabulum). Overall reproducibility of (1)H MR spectroscopy and dynamic contrast-enhanced imaging tended to be best in areas with the highest inherent fat fraction or perfusion.

CONCLUSION

Reproducibility of (1)H MR spectroscopy or perfusion imaging is sufficiently high to warrant these techniques being applied to the longitudinal study of bone diseases.

An in vivo magnetic resonance imaging technique for measurement of rat lumbar vertebral body blood perfusion

The technical feasibility of dynamic contrast-enhanced magnetic resonance imaging (MRI) measurement of rat vertebral blood perfusion using a 1.5 T clinical scanner and a small surface coil was investigated in this study. Nine male 7-month-old Wistar-Kyoto rats were used. Computed tomographic assessment of lumbar vertebral bone mineral density (BMD) and MRI assessment of lumbar vertebral blood perfusion were performed twice with 8 weeks' interval. A 4.7 cm surface coil was used for receiving radiofrequency signal. Gadolinium-DOTA (0.3 mmol/kg) was injected through the tail vein of the rat as a quick bolus and dynamic MRI scan was carried out on the central sagittal plane of the lumbar spine for 8 min with a temporal resolution of 0.6 s. Blood perfusion parameters of wash-in rate, maximum enhancement and wash-out rate were derived from the dynamic MR images. No vertebral body size and vertebral BMD difference was detected between the two time points ( P = 0.222 and 0.123, respectively). Wash-in rate was 0.105 (±0.016)% and 0.111 (±0.018)%, maximum enhancement 126.5 (±10.6)% and 129.2 (±13.4)%, and wash-out rate 0.788 (±0.182)% and 0.792 (±0.182)% for the two time points. With these parameters, no difference was found between the two time points with a P value of 0.575, 0.889 and 0.754, respectively. We conclude that dynamic contrast-enhanced MRI measurement of rat vertebral blood perfusion using a 1.5 T clinical scanner and a small surface coil is feasible and reliable. This technique offers a non-invasive means to probe vertebral blood perfusion changes associated with rat disease models.

A study of bone marrow and subcutaneous fatty acid composition in subjects of varying bone mineral density

Osteoporosis is associated with an increase in marrow fat. Fats, particularly polyunsaturated fats, either in co-cultures or diet, have been shown to significantly influence bone remodeling. Whether the increase in marrow fat seen in osteoporosis is also associated with a change in fatty acid composition is not known. This study was undertaken to investigate the fatty acid composition in subjects of varying bone mineral density (BMD). Samples of marrow fat and subcutaneous fat from 126 subjects (98 females, 34 males, mean age 69.7+/-10.5 years) undergoing orthopedic surgery were analyzed for fatty acid composition by gas chromatography. These results were correlated with BMD assessed by DXA. A total of 22 fatty acids were identified in marrow and subcutaneous fat. Significant differences in fatty acid composition existed between marrow and subcutaneous fat as well as between marrow fat samples obtained from the proximal femur and proximal tibia. Other than cis-7-hexadecenoic acid [C16:1 (n=9)] and docosanoic acid [C22:0], no difference in marrow fatty acid composition was evident between subject groups of varying BMD (normal, low bone mass, and osteoporosis). In conclusion, there exists a wide range of individual fatty acids in marrow fat. Marrow fatty acid composition differs from that of subcutaneous fat and varies between predominantly erythropoetic and fatty marrow sites. Other than cis-7-hexadecenoic acid [C16:1 (n=9)] and docosanoic acid [C22:0], no difference in marrow fatty acid composition was evident between subjects of varying BMD.

Magnetic resonance imaging in adolescent painful flexible flatfoot

BACKGROUND

The cause of navicular tuberosity pain in adolescents with flexible flatfeet is not well understood. We hypothesized that some of the navicular tuberosity pain may be related to insertional enthesopathy of the posterior tibial tendon at the navicular. Magnetic resonance imaging was performed to look for abnormal signal changes in a series of patients.

MATERIAL AND METHOD

Consecutive adolescent patients presenting with flexible flatfeet and navicular tuberosity pain were prospectively recruited. A detailed foot examination and body fat analysis was performed. Standing radiographs and Tekscan pedobarograph of both feet were obtained. Magnetic resonance examinations were performed on a 1.5-T whole-body magnetic resonance imaging system utilizing a standard extremity coil.

RESULTS

MRI abnormality was detected in 15 of the 36 feet in 18 adolescents examined. Abnormalities detected included thickening of the posterior tibial tendon insertion, marrow edema in the accessory navicular, marrow edema in the navicular tuberosity, and contrast enhancement at the posterior tibial tendon insertion site. Patients with MRI abnormalities were significantly taller, had a lower body mass index and a lower body fat percentage than those without MRI abnormality. Forward stepwise logistic regression analysis identified low body fat percentage and presence of an accessory navicular as independent predictors for abnormality on MRI.

CONCLUSION

MRI abnormality was frequently detected in adolescents with painful flexible flatfeet. The MRI signal changes indicated an enthesopathy like process occurring at the posterior tibial tendon insertion to the navicular which could explain the origin of pain in flexible flatfeet patients without an accessory navicular. Early identification and appropriate treatment to prevent progression may be helpful.

Pilot- and bench-scale testing of faecal indicator bacteria survival in marine beach sand near point sources

AIM

Factors affecting faecal indicator bacteria (FIB) and pathogen survival/persistence in sand remain largely unstudied. This work elucidates how biological and physical factors affect die-off in beach sand following sewage spills.

METHODS AND RESULTS

Solar disinfection with mechanical mixing was pilot-tested as a disinfection procedure after a large sewage spill in Los Angeles. Effects of solar exposure, mechanical mixing, predation and/or competition, season, and moisture were tested at bench scale. First-order decay constants for Escherichia coli ranged between -0.23 and -1.02 per day, and for enterococci between -0.5 and -1.0 per day. Desiccation was a dominant factor for E. coli but not enterococci inactivation. Effects of season were investigated through a comparison of experimental results from winter, spring, and fall.

CONCLUSIONS

Moisture was the dominant factor controlling E. coli inactivation kinetics. Initial microbial community and sand temperature were also important factors. Mechanical mixing, common in beach grooming, did not consistently reduce bacterial levels.

SIGNIFICANCE AND IMPACT OF THE STUDY

Inactivation rates are mainly dependent on moisture and high sand temperature. Chlorination was an effective disinfection treatment in sand microcosms inoculated with raw influent.

Effect of increasing vertebral marrow fat content on BMD measurement, T-Score status and fracture risk prediction by DXA

Quantitative examination of iliac crest bone biopsies shows that as subjects become older bone and functional marrow are replaced by adipose tissue. Studies of vertebral marrow fat using nuclear magnetic resonance spectroscopy ((1)H-MRS) show that subjects with lower spine T-scores have significantly higher marrow fat content. These findings suggest that the ability of DXA scans to determine fracture risk may be partly explained by the effect of increased marrow fat on BMD. However, a proper evaluation of the relationship between WHO spine T-score status and marrow fat content requires that the BMD data are first corrected for the bias caused by a selection effect in which subjects with higher marrow fat are more likely to be identified as having osteoporosis. In this study we have therefore reanalysed previously published data for 185 elderly Hong Kong Chinese subjects (103 women, mean age 73 y; 82 men, mean age 73 y) who had spine DXA scans and (1)H-MRS measurements of L3 marrow fat. The effect of varying marrow fat on BMD was modelled using vertebral body thicknesses measured in 50 men and women. Spine T-scores in each individual were adjusted for the measured marrow fat. Subjects were assigned to WHO categories based on their corrected T-scores, and the relationship between marrow fat and T-score status evaluated using regression analysis and analysis of variance. The average change in percent marrow fat per T-score unit was used to infer the fraction of the spine BMD fracture discrimination explained by marrow composition. The mean (SD) of the L1-L4 vertebral body thickness was 30.2 (2.1) mm for Hong Kong women and 33.4 (2.5) mm for men. A change in marrow fat content from 0 to 100% was estimated to produce a BMD decrease of 0.14 g/cm(2) (1.3 T-score units) in women and 0.16 g/cm(2) (1.3 T-score units) in men. Although adjusting spine BMD for marrow fat reduced the significance of the correlation, there was still a trend for marrow fat to increase with decreasing T-score with a slope of -1.2+/-0.7% per T-score unit (p=0.078) for women and -1.4+/-0.6% per T-score unit (p=0.023) for men. When the effect of marrow composition on fracture discrimination was evaluated the results showed that the higher vertebral marrow fat content found in osteoporotic subjects made a negligible contribution to the ability of spine BMD measurements to predict fracture risk.

Effect of osteoporosis on morphology and mobility of the lumbar spine

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

The purpose of this study was to examine disc morphology and spinal mobility in subjects with varying degrees of osteoporosis.

SUMMARY OF BACKGROUND DATA

There was limited information on the effect of osteoporosis on lumbar morphology and spinal mobility. It was also unclear how osteoporosis affects the nonosseous tissues such as the intervertebral disc.

METHODS

Ninety elderly subjects with varying bone mineral densities (22 normal, 28 osteopenia, 40 osteoporosis) were recruited from an osteoporosis clinic. Lateral radiographs and magnetic resonance images of their lumbar spines were obtained. An electromagnetic tracking device was employed to measure the ranges of motion of the whole lumbar spine.

RESULTS

Although the thoracic spine had been shown to have decreased anterior vertebral body height in subjects with osteoporosis, this study revealed that the anterior height was increased in the lumbar region. Osteoporosis was associated with expansion of the middle of the disc with corresponding collapse of vertebral bodies, but osteoporosis was found not to be related to either disc preservation or degeneration. No significant change in spinal mobility was observed in patients with osteoporosis.

CONCLUSION

Osteoporosis does not only affect the bone but also the nonosseous tissues. It was found to be associated with expansion of the intervertebral disc, which was likely to be secondary to changes in the vertebral endplate.

A novel semisynthesized small molecule icaritin reduces incidence of steroid-associated osteonecrosis with inhibition of both thrombosis and lipid-deposition in a dose-dependent manner

BACKGROUND

Intravascular-thrombosis and extravascular-lipid-deposition are the two key pathogenic events considered to interrupt intraosseous blood supply during steroid-associated osteonecrosis (ON) development. However, there are no reported candidate agents capable of simultaneously targeting these two key pathogenic events. The authors' published experimental studies have shown that Epimedium-derived flavonoids possess an anti-ON effect. Further, the authors have recently identified a small molecule Icaritin as an intestinal metabolite of Epimedium-derived flavonoids.

OBJECTIVE

The present study was to evaluate the prevention effect of the available semisynthesized small molecule Icaritin on steroid-associated ON development in a rabbit model.

METHODS

After receiving an established inductive protocol for inducing steroid-associated ON, eighty-four male 28-week-old New-Zealand white rabbits were divided into the following three daily oral administration groups, including low dose Icaritin group (L-ICT; n=28; 5 mg x kg(-1) x day(-1)), high dose Icaritin group (H-ICT; n=28; 10 mg x kg(-1) x day(-1)), and control vehicle group (CON; n=28). Before and after induction, dynamic contrast-enhanced MRI was performed on proximal femur for intra-osseous perfusion function index. Meanwhile, blood samples were examined for coagulation, fibrinolysis, lipid-transportation, endothelium injury, oxidative stress, and hepatocyte injury index, while marrow samples were quantified for adipogenic potential index of mesenchymal stem cell by in vitro culture and proliferator-activated receptor-gamma (PPARgamma) protein expression by western blot. At baseline, week 1 and 2 post-induction, 4, 8 and 16 rabbits in each group were sacrificed, respectively. After sacrifice, femora were dissected for micro-CT-based micro-angiography, followed by histological examination of ON lesion, intravascular thrombosis, extravascular fat-cell and vascular endothelial growth factor (VEGF) localized expression.

RESULTS

The ON incidence in the L-ICT and H-ICT groups was both significantly lower than that in the CON group (p<0.05 for both). The ON incidence in the H-ICT group was significantly lower than that in the L-ICT group (p<0.05). A significant decrease in the vascularization index and a significant increase in the permeability index seen in the CON group was attenuated in the L-ICT group and almost prevented in the H-ICT group at week 1 post-induction. Reduced perfusion to vessel-like structural units was more rarely found in the H-ICT group than in the L-ICT group. Regarding intravascular thrombosis, a significant increase in the thrombotic vessel count, endothelium injury index, coagulation index, and a significant decrease in both the fibrinolysis and oxidative stress index in the CON group were attenuated in the L-ICT group and prevented in the H-ICT group. For extravascular lipid-deposition, a significant increase in the fat cell area fraction, adipogenic potential index, PPARgamma expression and lipid-transportation index in the CON group was attenuated in the L-ICT group and prevented in the H-ICT group. Increased immunoreactivity of VEGF in the CON group was attenuated in the L-ICT group and prevented in the H-ICT group. Regarding safety, the hepatocyte injury index did not show significant change from baseline in any group.

CONCLUSION

Icaritin, a novel semisynthesized small molecule with osteoprotective potential, exerts dose-dependent effect on reducing incidence of steroid-associated ON with inhibition of both intravascular thrombosis and extravascular lipid-deposition. Suppression of the up-regulated PPARgamma expression for extravascular adipogenesis of mesenchymal stem cells and protection from activated oxidative stress for intravascular endothelium injury were found to be involved in the underlying mechanisms.

The incidence of deep venous thrombosis in Chinese medical Intensive Care Unit patients

OBJECTIVE

To evaluate the incidence of deep venous thrombosis in critically ill, Intensive Care Unit patients of Chinese ethnicity.

DESIGN

Prospective, observational study.

SETTING

Intensive Care Unit in a Hong Kong teaching hospital.

PATIENTS

Consecutive adult Chinese medical patients not receiving pharmacological or mechanical prophylaxis for deep venous thrombosis.

MAIN OUTCOME MEASURES

Compression and duplex Doppler ultrasound examinations of the lower limbs within 24 hours of admission and twice weekly thereafter during their Intensive Care Unit stay. After discharge, a 1-week follow-up investigation was also performed. Demographic data and risk factors for deep venous thrombosis were prospectively recorded.

RESULTS

Over a 9-month study period, 80 patients were investigated. Deep venous thrombosis was detected by ultrasound examination in 15 (19%) of the patients (95% confidence interval, 14-23%). Nine of 15 had isolated below-knee deep venous thrombosis, and of these, five had bilateral involvement. Characteristics of patients with or without deep venous thrombosis were similar. Of the 15 patients who had a positive ultrasound examination, only four (27%) had clinical signs of deep venous thrombosis. Of the 65 patients without a positive ultrasound examination, only two (3%) had positive clinical signs (P=0.01). This yielded a moderate positive likelihood ratio of 9 (95% confidence interval, 2-43) and a small negative likelihood ratio of 0.76 (95% confidence interval, 0.56-1.03). There were no cases of pulmonary embolism. Hospital mortality in those with and without deep venous thrombosis was 33% and 28%, respectively.

CONCLUSIONS

In the absence of prophylaxis, the incidence of deep venous thrombosis in Chinese medical Intensive Care Unit patients is lower than that reported in similar Caucasian patients, but higher than expected. As clinical features are not able to reliably exclude the presence of deep venous thrombosis, early routine prophylaxis for deep venous thrombosis in Chinese medical Intensive Care Unit patients should be considered.

Bone mass and architecture determination: state of the art

Bone fracture occurs when the bone strength (i.e. the ability of the bone to resist a force) is less than the force applied to the bone. In the elderly, falls represent the more severe forces applied to bone. Bone density is a good marker of bone strength, and has been used widely in this respect. Nevertheless, many aspects of bone strength cannot be explained by bone density alone. For this reason there has been increasing interest in studying architectural parameters of bone, beyond bone density, which may affect bone strength. Macro-architectural parameters include e.g. bone size and geometry assessed with techniques such as radiography, dual-energy x-ray absorptiometry (DXA), peripheral quantitative computed tomography (QCT), computed tomography (CT) and magnetic resonance imaging (MRI). Micro-architectural parameters include fine cortical and trabecular structural detail which can be evaluated using high-resolution imaging techniques such as multidetector CT, MRI, and high-resolution peripheral QCT. These techniques are providing a great deal of new information on the physiological architectural responses of bone to aging, weightlessness, and treatment. This will ultimately lead to the prediction of fracture risk being improved through a combined assessment of bone density and architectural parameters.

Sonography of chronic Achilles tendinopathy: a case-control study

PURPOSE

To describe the sonographic appearance of Achilles tendon in normal subjects and patients with chronic Achilles tendinopathy with the aim of establishing diagnostic sonographic criteria for Achilles tendinopathy.

METHODS

A prospective, cross-sectional, case-control sonographic study of the Achilles tendon was undertaken. Thirty tendons in 21 patients and 100 tendons in 50 control subjects were selected. Sonographic assessment included tendon thickness, echogenicity, fibrillar pattern, and presence of calcifications. Power Doppler imaging was used to assess tendon vascularity. Paratendinous structures and plantar fascia were also examined.

RESULTS

Tendinopathic tendons were larger than normal tendons in both cross-sectional area and antero-posterior diameter. Hypoechoic areas within the tendon were more commonly seen in patients. Disruption of fibrillar pattern, increase in tendon vascularity, increased Kager's fat pad echogenicity, and paratenon thickening were solely seen in patients. Fluid in the retrocalcaneal bursa and calcaneal bony abnormalities were seen in both groups without a significant difference.

CONCLUSION

Achilles tendinopathy results in enlargement, particularly of the mid- and distal portions of the tendon, disruption of fibrillar pattern, and increase in tendon vascularity. Additional signs are increased Kager's fat pad echogenicity and paratenon thickening. Tendon calcification, changes in retrocalcaneal bursae, and calcaneal contour are not specific for Achilles tendinopathy.

Effect of vertebral morphology on lumbar kinematics in elderly subjects with decreased bone mineral density

Correlation between kinematics and morphological characteristics of lumbar spine was studied in subjects with varying bone mineral density. Effect of morphological characteristics and bone mineral density on the lumbar spine movement was investigated. Morphology parameters were measured from radiographs and a high-frequency motion tracking device were employed to detect surface movement of lumbar spine. Multiple regression analysis identified factors influencing lumbar kinematics while ANOVA examined differences in morphology with normal bone mineral density, osteopenia and osteoporosis. The results show that morphological characteristics, such as wedging deformity, are indeed influential to the kinematics. Related to our previous report, abnormal lumbar kinematic pattern in the subjects with osteoporosis, this study shows although morphological characteristics were found significantly different among normal, osteopenia, and osteoporosis subjects, the change in lumbar kinematic pattern could not be fully explained by the altered vertebral or disc morphology.

Concurrent chemoradiotherapy or endoscopic stenting for advanced squamous cell carcinoma of esophagus: a case-control study

BACKGROUND

We evaluated the role of chemoradiotherapy (CRT) for patients with inoperable squamous esophageal cancer.

METHODS

Patients with locally advanced or metastatic squamous esophageal carcinoma who received CRT were recruited. The CRT consists of continuous infusion of 5-fluorouracil at 200 mg/m(2)/day, and cisplatin at 60 mg/m(2) on days 1 and 22, with concurrent radiotherapy for a total of 50 to 60 Gy in 25 to 30 fractions over 6 weeks. Efficacy was assessed by endoscopy and computed tomographic scan before and 8 weeks after completion of the treatment program. Median survival and the need for palliative esophageal stenting were compared with another group of patients who received endoscopic stenting.

RESULTS

From 1996 to 2003, a total of 36 consecutive patients (33 male, mean +/- SD age 63.2 +/- 9.5 years) with T4 disease (81%) with or without cervical nodal metastasis (50%) received CRT, while 36 patients treated with endoscopic stenting alone were recruited as controls. Both groups were comparable in demographics, pretreatment dysphagia score, comorbidities, and tumor characteristics. CRT was completed in 32 patients (89%). There was no treatment-related mortality. Tumor volume was greatly reduced after CRT in 19 patients. Four patients (11%) received salvage esophagectomy 9 to 42 months after CRT. Compared with the stenting group, CRT statistically significantly improved 5-year survival (15% vs. 0%, P = .01), median survival (10.8 months vs. 4.0 months, P < .005), and need for stenting (22% vs. 100%, P = .005).

CONCLUSIONS

Palliative CRT can effectively improve the symptoms of dysphagia in patients with inoperable squamous esophageal carcinoma. It results in better survival compared with endoscopic stenting in these patients.

Analysis of bone marrow fatty acid composition using high-resolution proton NMR spectroscopy

High-resolution 1H NMR spectroscopy as a complementary method in the analysis of human bone marrow fatty acid (FA) composition was examined. Marrow FA composition in 10 bone samples measured by NMR and gas chromatography (GC) were compared. NMR T1 relaxation time of FA was determined and reproducibility tests were performed to assess the variability. Good correlations were obtained between the NMR and GC results for omega-6 polyunsaturated fatty acid (PUFA) (Spearman r, 0.878), omega-3 PUFA (0.895), monounsaturated FA (0.964) and saturated FA (0.939). The NMR method tended to overestimate saturated FA and underestimate omega-3/omega-6 ratio compared to GC results. T1 relaxation time of marrow FA was 0.56-3.65s. Coefficient of variation of the NMR method was 0.6-8.2% in intra-experimental and 0.2-8.4% in inter-experimental measurements. This study demonstrates a complementary role for 1H NMR spectroscopy as an additional analytical tool in human lipid research.

First-time shoulder dislocation: High prevalence of labral injury and age-related differences revealed by MR arthrography

PURPOSE

To evaluate abnormalities and age-related differences after first-time shoulder dislocation.

MATERIALS AND METHODS

MRA images of first-time dislocators were assessed for labral-ligamentous-capsular / rotator cuff abnormalities and analyzed the age-related differences (< and >/=30 years old).

RESULTS

Sixty-six patients (34 <30 years old vs. 32 >/=30 years; 51 males; all anterior dislocations) were imaged. Forty-eight patients (73%) showed anteroinferior labral avulsion, consisting of: 6% (4/34 vs. 0/32) Perthes; 23% (8/34 vs. 7/32) free ALPSA (anterior labrum periosteal sleeve avulsion) lesion); 6% (1/34 vs. 3/32) adherent ALPSA; 23% (9/34 vs. 6/32) Bankart; 14% (5/34 vs. 4/32) inferiorly displaced avulsed labrum; 2% (1/34 vs. 0/32) GLAD. Extensive labral detachment (extended above 3 o'clock position) was present in 31% (11/28 vs. 4/20). There were 14% (6/34 vs. 3/32) superior labrum anterior-posterior (SLAP) lesion; 27% (1/34 vs. 17/34) rotator cuff tendon tear; 71% (25/34 vs. 22/32) Hill-Sachs defect. Young patients were more likely to have extensive labral avulsions (P = 0.054), but less likely to have rotator cuff tears (P < 0.001).

CONCLUSION

A high prevalence and wide variety of labral avulsions after first-time shoulder dislocation, especially adherent ALPSA, inferiorly displaced avulsed labrum, or GLAD lesion, may influence treatment choice and outcome, suggesting a role for early MRA to assist in treatment triage.

Universal and discriminative detection using a miniaturized pulsed discharge detector in comprehensive two-dimensional GC

A miniaturized pulsed discharge detector (Mini-PDD) has been successfully demonstrated for comprehensive 2-D GC (GC x GC) analysis of pyrolysis gasoline and the pyrolysis GC x GC analysis of a polyethylene copolymer. The detector cell volume of the Mini-PDD is reduced to 25% of the Valco plug-in PDD D-3. An n-C11 peak width at base is 96 ms for the Mini-PDD, about 23% larger than a peak width of 78 ms detected by a flame ionization detector (FID). The Mini-PDD has sufficient response time for most GC x GC applications. When Mini-PDD is operated in helium photoionization mode (Mini He-PDD), it is a universal detector for both inorganic and organic compounds. This is especially useful when detection of water is needed in GC x GC applications. When krypton is doped in the helium discharge gas (Mini Kr-PDD), it can suppress signals of compounds having higher ionization potentials and enhance relative signal intensities of aromatic compounds. The determination of aliphatic to aromatic hydrocarbon ratios is essential to the operation of petroleum crackers. Comparison of the signal from two modes of the Mini-PDD is a simple and fast way to verify the location of aromatics in comprehensive 2-D gas chromatograms.

Vertebral marrow fat content and diffusion and perfusion indexes in women with varying bone density: MR evaluation

PURPOSE

To prospectively study the relationship among vertebral marrow fat content, marrow diffusion indexes, and marrow and erector spinae muscle perfusion indexes in female subjects with varying bone mineral density.

MATERIALS AND METHODS

Institutional study approval and informed consent were obtained. Dual x-ray absorptiometry, proton magnetic resonance (MR) spectroscopy, diffusion-weighted MR imaging, and dynamic contrast material-enhanced MR imaging of the lumbar spine and erector spinae muscle were performed in 110 women (mean age, 73 years; range, 67-84 years). Marrow fat content, marrow apparent diffusion coefficient (ADC), and perfusion indexes (maximum enhancement and enhancement slope) of marrow and erector spinae muscle were compared among three bone density groups (normal, osteopenic, and osteoporotic). The t test comparisons and Pearson correlations were applied.

RESULTS

Seven subjects were excluded, which yielded a final cohort of 103 subjects: 18 with normal bone density, 30 with osteopenia, and 55 with osteoporosis. Vertebral marrow fat content was significantly increased in the osteoporotic group (67.8% +/- 8.5 [standard deviation]) when compared with that of the normal bone density group (59.2% +/- 10.0, P = .002). Vertebral marrow perfusion indexes were significantly decreased in the osteoporotic group (enhancement slope, 1.10%/sec +/- 0.51) compared with those of the osteopenic group (1.45%/sec +/- 0.51, P = .01) and normal bone density group (1.70%/sec +/- 0.52, P < .001). Erector spinae muscle perfusion indexes did not decrease as bone density decreased. The ADC of vertebral marrow did not change with bone density.

CONCLUSION

The subjects experienced a decrease in vertebral marrow maximum enhancement and enhancement slope and an increase in marrow fat content as bone density decreased. The reduction in perfusion indexes occurred only within the vertebral body and not in the paravertebral tissues supplied by the same artery.

Diagnosis and imaging of ankle instability

Ankle instability is a major cause of symptoms following an ankle sprain. With a thorough history and examination, appropriate additional investigations, including cross-sectional imaging, and thoughtful interpretation of the information, one should rarely be caught out by misdiagnosis, multiple diagnoses, or unusual causes.

Sung JJ, K. Lam CW. Steroid-induced osteonecrosis in severe acute respiratory syndrome: a retrospective analysis of biochemical markers of bone metabolism and corticosteroid therapy

Aim

We investigated the effect of massive doses of corticosteroid therapy on bone metabolism using specific biochemical markers of bone metabolism, and the prevalence of osteonecrosis in severe acute respiratory syndrome (SARS) patients at a university teaching hospital in Hong Kong.

Methods

Seventy-one patients with a clinical diagnosis of SARS were studied according to the modified World Health Organization case definition of SARS who were involved in the SARS epidemic between 10 March and 20 June 2003. The clinical diagnosis was confirmed by serological test and/ or molecular analysis. Biochemical markers of bone metabolism were analysed retrospectively using serial clotted blood samples collected from each patient during the course of hospital admission to discharge and subsequent follow-up at out-patient clinic using the arbitrary time periods: (i) Day <10; (ii) Day 28-44; (iii) Day 51-84; and (iv) Day >90 after the onset of fever. Magnetic resonance imaging of the knee and hip joints were performed post-admission to evaluate the prevalence of osteonecrosis amongst these SARS patients. Various risk factors for the development of osteonecrosis were assessed using receiver operating characteristics curve comparison with appropriate test statistics and Spearman’s coefficients of rank correlation with biochemical bone markers.

Results

Biochemical markers of bone metabolism showed significant bone resorption as evidenced by a marked increase in serum C-terminal telopeptide concentration (CTx) from Day 28-44 after the onset of fever. With tapering down of corticosteroid dosage, CTx started to return to previous baseline level from Day 51 onwards, while other bone formation markers, serum osteocalcin and bone- specific alkaline phosphatase concentrations (OC and BALP, respectively), started to increase. The latter effect was even more marked after Day >90. Seven patients developed radiological evidence of osteonecrosis. The prevalence of osteonecrosis in this cohort was 9.9%. A total corticosteroid dosage of >1900mg hydrocortisone, >2000 mg methylprednisolone, >13 340 mg hydrocortisone-equivalent corticosteroid therapy, and >18 days on corticosteroid therapy were found to be significant risk factors for the subsequent development of osteonecrosis. There were also significant positive correlations amongst various biochemical bone markers in this patient cohort.

Conclusion

Both bone resorption and formation markers were unable to predict the subsequent development of osteonecrosis. The use of high dose of hydrocortisone or methylprednisolone for an extended duration was shown to be a significant risk factor for osteonecrosis. Its prevalence in this cohort is comparable to those reported in the literature for SARS patients with high-dose corticosteroid therapy. The Day 28–44 increase in the serum CTx coincided with the timing of corticosteroid use. The Day >51 increase in serum OC and BALP coincided with the timing of corticosteroid withdrawal.

Rapid improvement in rheumatoid arthritis patients on combination of methotrexate and infliximab: clinical and magnetic resonance imaging evaluation

The objectives of this study was to assess, using clinical and magnetic resonance imaging (MRI) criteria, the efficacy of combination infliximab therapy in patients with active rheumatoid arthritis (RA) refractory to methotrexate (MTX) treatment and to ascertain whether the changes in MRI parameters correlate with the clinical response. Four infusions of infliximab (3 mg/kg) at weeks 0, 2, 6, and 14 were added to a stable background dose of MTX in 19 patients with active disease. Clinical parameters were assessed before each infusion and at week 14. Dynamic contrast-enhanced MRI examination of the most severely affected wrist was performed at baseline and week 14. Synovitis severity, volume of synovitis, and synovial perfusion indices were evaluated. Significant improvement in all clinical disease activity parameters was seen at week 14 with reduction in C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and DAS28. Sixty-eight percent of patients achieved ACR20. MRI disease activity parameters also significantly decreased after treatment with reduction in grading of synovitis, volume of active synovitis, and perfusion enhancement slope. Significant positive correlations were seen between the baseline volume of synovitis and the pain score (r=0.65), patient global score (r=0.68), and health assessment questionnaire (HAQ) score (r=0.46). In conclusion, addition of infliximab to methotrexate rapidly reduces inflammation in longstanding patients with RA. Assessment of enhancing synovial volume and perfusion indices on serial MRI examination was helpful in documenting the effect of treatment over this short period.

Bone mineral density and the risk of peripheral arterial disease in men and women: results from Mr. and Ms Os, Hong Kong

Previous population studies have demonstrated an association between peripheral vascular disease and bone mineral density in women, but not in men. In a large prospective cohort of 3,998 Chinese men and women aged 65 to 92 years of age in Hong Kong, the association between peripheral vascular disease and bone mineral density was explored. Demographic and lifestyle information was obtained from face to face interviews using a standardized questionnaire. This included demographic information, medical history and lifestyle factors. Physical examination measurements included anthropometry and tibial and brachial systolic blood pressures. The ratio of the posterior tibial and brachial systolic blood pressures, the ankle/arm index, was used as a measure of peripheral arteriosclerosis in the lower extremities. Bone mineral density (BMD) at the total hip and spine (L1-L4) was measured by Hologic QDR-4500 W densitometers (Hologic, Inc., Waltham, Mass.). In this cross-sectional analysis, the ankle brachial index (ABI) was positively correlated with hip BMD (correlation coefficient=0.27; P<0.001). However, after adjustment for confounders, the correlation became much weaker (correlation coefficient=0.03; P<0.05). This showed that much of the relationship between ABI and BMD could be explained by other confounders. In multiple regression analysis, an increase in ABI of 1 SD of ABI was associated with an increase of 0.5% (95% CI: 0.02%, 0.9%) in hip BMD after adjusting for age, sex, body weight, smoking status, history of diabetes, cardiovascular diseases, use of thiazide diuretics, grip strength and physical activity. Although our study shows that peripheral vascular disease in the lower extremities may be associated with decreased bone mineral density, the association is weak especially after adjustment was made for confounders. This indicates that other factors may be contributing to the association between peripheral vascular disease and osteoporosis.

Osteoporosis is associated with increased marrow fat content and decreased marrow fat unsaturation: a proton MR spectroscopy study

PURPOSE

To use proton magnetic resonance spectroscopy ((1)H-MRS) to evaluate vertebral marrow fat, and to determine whether bone density correlates with fat content and fat unsaturation levels in postmenopausal women.

MATERIALS AND METHODS

Fifty-three women (mean age = 70 years) underwent dual energy x-ray absorptiometry and (1)H-MRS, and 12 young female controls (mean age = 28 years) underwent (1)H-MRS of the lumber spine. Water and lipid peak amplitudes were measured to calculate fat content and fat unsaturation index. Spearman's correlation tests and a t-test comparison of means were applied.

RESULTS

(1)H-MRS was successful in 15 normal, 15 osteopenic, and 20 osteoporotic subjects, and in all controls. Marrow fat content was significantly elevated in osteoporotic (65.5% +/- 10%) and osteopenic (63.5% +/- 9.3%) subjects compared to normal subjects (56.3% +/- 11.2%) and young controls (29% +/- 9.6%). The fat unsaturation index was significantly decreased in osteoporotic (0.091 +/- 0.013) and osteopenic (0.097 +/- 0.014) subjects compared to normal subjects (0.114 +/- 0.016) and young controls (0.127 +/- 0.031). A good inverse correlation was observed between the fat content and the unsaturation index (r(s) = -0.53, P < 0.0001).

CONCLUSION

Osteoporosis is associated with increased marrow fat. As marrow fat increases, saturated lipids appear to increase preferentially to unsaturated lipids.

Bone Scintigraphy in Common Tumors With Osteolytic Components

Osteolytic lesions are frequently encountered in clinical practice. Radionuclide bone scans with technetium-99m-labeled diphosphonates are often performed in the evaluation of both solitary and multiple osteolytic lesions. In this pictorial review, we critically evaluate the current role of bone scan in common osteolytic tumors including aneurysmal bone cyst, simple bone cyst, fibrous dysplasia, nonossifying fibroma, giant cell tumor, eosinophilic granuloma, enchondroma, chondrosarcoma, osteosarcoma, Ewing sarcoma, myeloma, and metastases. The merits and limitations of bone scanning are emphasized.

Vertebral bone mineral density, marrow perfusion, and fat content in healthy men and men with osteoporosis: dynamic contrast-enhanced MR imaging and MR spectroscopy

PURPOSE

To prospectively use hydrogen 1 (1H) magnetic resonance (MR) spectroscopy and dynamic contrast material-enhanced MR imaging to measure vertebral body marrow fat content and bone marrow perfusion in older men with varying bone mineral densities as documented with dual x-ray absorptiometry (DXA).

MATERIALS AND METHODS

This study had institutional review board approval, and all participants provided informed consent. DXA, 1H MR spectroscopy, and dynamic contrast-enhanced MR imaging of the lumbar spine were performed in 90 men (mean age, 73 years; range, 67-101 years). Vertebral marrow fat content and perfusion (maximum enhancement and enhancement slope) were compared for subject groups with differing bone densities (normal, osteopenic, and osteoporotic). The t test was used for comparisons between groups, and the Pearson test was used to determine correlation between marrow fat content and perfusion indexes.

RESULTS

Eight subjects were excluded, yielding a final cohort of 82 subjects (mean age, 73 years; range, 67-101 years) that included 42 subjects with normal bone density (mean T score, 0.8 +/- 1.1 [standard deviation]), 23 subjects with osteopenia (mean T score, -1.6 +/- 0.4), and 17 subjects with osteoporosis (mean T score, -3.2 +/- 0.5). Vertebral marrow fat content was significantly increased in subjects with osteoporosis (mean fat content, 58.23% +/- 7.8) (P = .002) or osteopenia (mean fat content, 55.68% +/- 10.2) (P = .034) compared with that in subjects with normal bone density (50.45% +/- 8.7). Vertebral marrow perfusion indexes were significantly decreased in osteoporotic subjects (mean enhancement slope, 0.78%/sec +/- 0.3) compared with those in osteopenic subjects (mean enhancement slope, 1.15%/sec +/- 0.6) (P = .007) and those in subjects with normal bone density (mean enhancement slope, 1.48%/sec +/- 0.7) (P < .001).

CONCLUSION

Subjects with osteoporosis have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with osteopenia. Similarly, subjects with osteopenia have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with normal bone density.

Computed tomography for cervical spine trauma. The impact of MDCT on fracture detection and dose deposition

A multidetector computed tomography (MDCT) was installed in our department. Referral rates, examination protocols and detection rates of abnormal findings in CT examinations for cervical spine trauma 6 months before and 6 months after MDCT installation were compared to look for changes in practice. Retrospective analysis of all CT cervical spine examinations in patients with multiple trauma over two contiguous 6-month periods: from July 2003 to December 2003 (helical CT) and from January 2004 to June 2004 (MDCT). Variables recorded were number of CT examinations performed, scan plane coverage and traumatic abnormalities detected. Phantom dosimetry measurements for cervical spine examination in both helical CT and MDCT were compared. One hundred and fifty four patients underwent cervical spine CT during these periods. Helical CT period: of 91 patients undergoing CT cervical spine examination for trauma, 65 (71%) were complete cervical examinations and 26 (29%) were level-specific examinations. Eight patients (9%) had cervical spine fracture, six of which were apparent on radiographs. Dose estimations for thyroid, lens and breast were 24.76, 1.86 and 0.21 mGy, respectively, for complete cervical spine examinations. MDCT period: of 63 patients who underwent CT cervical spine examination for trauma, 61 (97%) were complete examinations and 2 (3%) were level-specific examinations. Six patients (11%) had cervical spine fracture, three of which were apparent on radiographs. Dose estimations for thyroid, lens and breast were 75.8, 9.7 and 0.7 mGy, respectively, for complete cervical spine examinations, which were notably higher than those for helical CT. After installation of MDCT, clinical requests for complete examination of the cervical spine following trauma increased. This changing trend resulted in a significantly higher radiation dose to thyroid, lens and breast.

Musculoskeletal infections: ultrasound appearances

Musculoskeletal infections are commonly encountered in clinical practice. This review will discuss the ultrasound appearances of a variety of musculoskeletal infections such as cellulitis, infective tenosynovitis, pyomyositis, soft-tissue abscesses, septic arthritis, acute and chronic osteomyelitis, and post-operative infection. The peculiar sonographic features of less common musculoskeletal infections, such as necrotizing fasciitis, and rice body formation in atypical mycobacterial tenosynovitis, and bursitis will also be presented.

Effects of vitamins C and E on oxidative stress markers and endothelial function in patients with systemic lupus erythematosus: a double blind, placebo controlled pilot study

OBJECTIVE

Patients with systemic lupus erythematosus (SLE) experience excess morbidity and mortality due to coronary artery disease (CAD) that cannot be fully explained by the classical CAD risk factors. Among emerging CAD risk factors, oxidative stress is currently being emphasized. We evaluated the effects of longterm antioxidant vitamins on markers of oxidative stress and antioxidant defense and endothelial function in 39 patients with SLE.

METHODS

Patients were randomized to receive either placebo or vitamins (500 mg vitamin C and 800 IU vitamin E daily) for 12 weeks. Markers of oxidative stress included malondialdehyde (MDA) and allantoin. Antioxidants measured included erythrocyte superoxide dismutase and glutathione peroxidase, plasma total antioxidant power (as FRAP value), and ascorbic acid and vitamin E concentrations. Endothelial function was assessed by flow-mediated dilatation (FMD) of the brachial artery and plasma concentration of von Willebrand factor (vWF) and plasminogen activator inhibitor type 1 (PAI-1). Primary outcome of the study included the change in lipid peroxidation as revealed by MDA levels. Secondary outcomes included changes in allantoin and antioxidant levels and change in endothelial function.

RESULTS

After treatment, plasma ascorbic acid and alpha-tocopherol concentrations were significantly (p < 0.05) increased only in the vitamin-treated group, associated with a significant decrease (p < 0.05) in plasma MDA. Other oxidative stress markers and antioxidant levels remained unchanged in both groups. FMD and vWF and PAI-1 levels remained unchanged in both groups.

CONCLUSION

Combined administration of vitamins C and E was associated with decreased lipid peroxidation, but did not affect endothelial function in patients with SLE after 3 months of therapy.

Cruciate ligament avulsion fractures

PURPOSE

The objective of this study was to assess the variability of cruciate avulsion fractures.

TYPE OF STUDY

Retrospective observational study.

METHODS

Standardized radiographs and computed tomography (CT) examinations were performed in 40 patients (31 male, 9 female; age range, 10 to 77 years) with cruciate avulsion fractures.

RESULTS

The average age of patients with anterior cruciate ligament (ACL) avulsion fractures was 21.5 years and that of patients with posterior cruciate ligament (PCL) avulsion fractures was 42.9 years. Two basic patterns of avulsion fracture emerged. ACL fractures were either partial (62%) (with avulsion of anteromedial bundle) or extended (38%) and were comminuted in 25%. PCL fractures were either complete (47%) or extended (53%) and were comminuted in 50%. CT helped delineate fracture margins, comminution and extent.

CONCLUSIONS

Although there is considerable variability in fracture type, 2 basic patterns of ACL and PCL avulsion fractures exist. CT helps delineate these features as a prelude to surgical fixation.

LEVEL OF EVIDENCE

Level III.

Early magnetic resonance imaging of radiographically occult osteoporotic fractures of the femoral neck

Osteoporosis is associated with thinning of cortical and trabecular bone, which reduces bone strength and predisposes individuals to fracture development. Femoral neck fractures in patients with osteoporosis may not be apparent on radiographs. Magnetic resonance imaging is useful at detecting these radiographically occult fractures; yet, the practice has not been widely adopted in Hong Kong. In this article, we review our experience of early magnetic resonance imaging in this clinical context--that is, imaging performed within 48 hours of presentation to hospital. Twenty-eight patients (age range, 69-93 years) over a 3-year period were studied. Magnetic resonance imaging revealed radiographically occult neck fractures in 14 (50%) cases (equivalent to 4% of all femoral neck fractures). These fractures were treated surgically (64%) or conservatively (36%) with good bone healing and clinical outcome. When no femoral neck fracture was present, magnetic resonance imaging revealed an alternative cause for symptoms in all 14 cases. We strongly endorse the use of early magnetic resonance imaging for patients with osteoporosis who have a clinically suspected femoral neck fracture that is not visible radiographically.

Does Doppler analysis of musculoskeletal soft-tissue tumours help predict tumour malignancy?

AIM

To investigate whether analysing vascularity of soft-tissue tumours on ultrasound assists differentiating benign from malignant tumours.

MATERIALS AND METHODS

One hundred and forty-eight vascular soft-tissue tumours in 148 patients (88 males, mean age 45.6 years) were studied. Final diagnosis was established histologically in 95 (64%) of cases. For each tumour, three-colour Doppler imaging features (vascularity, vascular density, vascular organization) and 13 pulsed Doppler (spectral analysis) parameters were assessed. Data analysis was performed to isolate optimal discriminatory criteria for differentiating benign from malignant tumours.

RESULTS

Significantly more benign soft-tissue tumours had an organized vascular pattern on colour Doppler imaging. If the vascular pattern is organized, this is a good indicator of tumour benignity. However, this pattern was apparent in less then one-third of the soft-tissue tumours. Benign tumours also had significantly higher minimum end diastolic velocity (EDVmin) and lower mean ratio of resistive index (RImean) than malignant soft-tissue tumours, though considerable overlap existed between the two groups.

CONCLUSION

Colour Doppler imaging analysis of soft-tissue tumours is of limited value when differentiating benign from malignant tumours. If an organized vascular pattern is present, the tumour is more likely to be benign. Flow characteristics were not specific enough to be applicable in clinical practice.

Comparison of Thoracic Ultrasound, Clinical Acumen, and Radiography in Patients with Minor Chest Injury

BACKGROUND

This study was designed to compare ultrasonography, clinical findings, and radiography in the detection of rib and sternal fractures.

METHODS

In a prospective study, 88 patients presenting consecutively to an emergency department with isolated blunt chest injury of mild to moderate force were recruited.

RESULTS

Ultrasonography yielded a sensitivity of 80.3 (95% confidence interval [CI], 69.5-88.5) for detecting chest wall fractures compared with sensitivities of 26.0 (95% CI, 15.8-36.3) for clinical acumen and 23.7 (95% CI, 14.7-34.8) for radiography.

CONCLUSION

Early ultrasonography is more accurate than clinical and radiologic evaluation at detecting rib and sternal fractures.