Estimation of parameters affecting the uptake of 99mTc-methylenediphosphonate in rat femur with model simulation

The uptake of 99mTc-methylenediphosphonate (MDP) in different parts of rat femur was simulated using a local three-space model for tracer transfer. The model consisted of bone blood, bone ECF-space and space for tracer deposition. The measured 99mTc-MDP concentration in the systemic blood and the local bone blood flow measured by 131I-macroaggregated albumin microspheres were used as input parameters. The measured blood flow values were 6.3, 3.1 and 15.3 ml/100 g/min for proximal, middle and distal femur, respectively. The model parameters that gave the best fit to measured 99mTc-MDP uptake curves in computer simulation showed that bone blood flow, volume of ECF-space, permeability surface area product and accretion constant from ECF-space to space for tracer deposition were highest in distal and lowest in middle femur. The values corresponded to peak extraction fractions of 0.38, 0.62, and 0.31 for proximal, middle and distal femur, respectively. We conclude that the simulation gives acceptable model parameters, and indicates applicability of a similar model into clinical quantitative bone scintigraphy.     

Estimation of parameters affecting the uptake of 99mTc-methylenediphosphonate in rat femur with model simulation

The uptake of ^99mTc-methylenediphosphonate (MDP) in different parts of rat femur was simulated using a local three-space model for tracer transfer. The model consisted of bone blood, bone ECF-space and space for tracer deposition. The measured ^99mTc-MDP concentration in the systemic blood and the local bone blood flow measured by ¹³¹I-macroaggregated albumin microspheres were used as input parameters. The measured blood flow values were 6.3, 3.1 and 15.3 ml/100 g/min for proximal, middle and distal femur, respectively. The model parameters that gave the best fit to measured ^99mTc-MDP uptake curves in computer simulation showed that bone blood flow, volume of ECF-space, permeability surface area product and accretion constant from ECF-space to space for tracer deposition were highest in distal and lowest in middle femur. The values corresponded to peak extraction fractions of 0.38, 0.62, and 0.31 for proximal, middle and distal femur, respectively. We conclude that the simulation gives acceptable model parameters, and indicates applicability of a similar model into clinical quantitative bone scintigraphy.     

Kohler disease: diagnoses and assessment by bone scintigraphy

Limping is a frequent occurrence in children and may be caused by various conditions, including trauma, inflammation, infection, and malignancy. Nontraumatic avascular necrosis of the tarsal bones should be included in the differential diagnosis. Accumulated data have supported the superiority of bone scans to radiography in the early diagnosis of avascular necrosis. Bone scintigraphy is a useful tool for investigating pain when symptoms, laboratory examinations, and radiography do not point to a specific diagnosis. In the early phase of disease, bone scans may demonstrate decreased tracer uptake (photopenic region), subsequently a hot area is seen during the reparative process. Although magnetic resonance imaging has important implications in the diagnosis of avascular necrosis, bone scintigraphy with its ready availability has a significant role as a primary tool in the evaluation of a limping child.     

动力髁螺钉或超关节外固定支架治疗股骨颈和转子良性病损病理性骨折

目的 探讨继发于股骨颈和转子良性病损病理性骨折的治疗方法.方法 回顾性研究2002-2004年间治疗的25例股骨近端良性病损病理性骨折患者.采取病灶刮除、苯酚烧灼、自体或异体骨移植,然后根据病损涉及股骨近端范围的大小,选择采用动力髁螺钉(DCS)或超髋关节外固定支架进行固定.平均随访时间为2.5年(2～4年).结果 所有患者术后3～6个月影像学上均可见良好的骨性愈合.未见局部复发和缺血性股骨头坏死及感染、骨折等并发症.采用美国骨与软组织肿瘤学会(Musculoskeletal Tumor Society,MSTS)-87、MSTS-93和多伦多保肢评分(Toronto Extremity Salvage Score,TESS)系统进行功能评估,均为良好和优秀.结论 与单纯植骨、牵引、髋"人"字石膏支具等传统方法相比,DCS或超髋关节外固定支架是治疗股骨颈和转子良性病损病理性骨折的又一可靠方法.     

Bone density distribution and gender dominate femoral neck fracture risk predictors

Objective. To determine whether regional characteristics of the proximal femur could discriminate between a group of patients who had just sustained a first low-trauma femoral neck fracture (n=50) from a group of healthy volunteers (n=123). Design. The application of an integral bone measurement (dual-energy X-ray absorptiometry) in conjunction with a volumetric cancellous bone density measurement (quantitative computed tomography) to the proximal femur in vivo provided an estimate of the contribution of the spatial distribution of bone density to hip fracture risk prediction. Results. The primary finding of this study was a significant difference between male and female hip fracture risk predictor variables. In men with femoral neck fracture, a significant decrease in bone density throughout the proximal femur was observed. In women with femoral neck fracture, a combination of local bone deficits (significant decrease in cancellous bone at the site of fracture, and a decrease in cortical bone at the site of impact) and significantly larger proximal femur dimensions (femoral neck and head widths) was evident. Conclusions. These results imply that effective hip fracture prevention strategies may require separate approaches for men and women. Screening programs for diminished bone density at the proximal femur have proved effective in previous studies. An approach which includes examining these local bone characteristics may further improve our ability to accurately determine hip fracture risk in vivo. Received: 30 July 1999 Revision requested: 6 October 1999 Revision received: 8 November 1999 Accepted: 18 November 1999     

Bone, bone marrow, and MIBI scintigraphic findings in Gaucher's disease "bone crisis"

PURPOSE: The authors report the utility of Tc-99m MIBI imaging in Gaucher's disease, which results in the accumulation of glucocerebroside in macrophages. Inflated macrophages, or Gaucher's cells, involve the reticuloendothelial organs. MATERIALS AND METHODS: A 38-year-old man with type I Gaucher's disease, splenectomy, and early bone involvement was examined for a low back "bone crisis." He had a history of total left hip replacement. Results of pelvic radiographs were normal. Magnetic resonance imaging showed complete infiltration of the bone marrow in the lumbar spine and the sacrum. The left iliac bone, the sacrum, and the adjacent part of L5 showed heterogeneously decreased uptake on bone scintigraphs. Hematopoietic bone marrow was absent in these regions and in the left femur. No infection of the prosthesis was revealed with labeled granulocytes. RESULTS: Avascular necrosis in the left iliac bone was diagnosed, which is a very unusual location. There was no uptake of MIBI in the iliac bones or the femurs. CONCLUSION: These findings suggest that MIBI may not be a good tool for the evaluation of medullary infiltration by Gaucher's cells.     

"Bounce at the Bell": a novel program of short bouts of exercise improves proximal femur bone mass in early pubertal children

Objectives: To examine the effects of a simple and inexpensive physical activity intervention on change in bone mass and structure in school aged children. Methods: Fifty one children (n = 23 boys and 28 girls; mean age 10.1 years) participated in "Bounce at the Bell" which consisted of 10 counter-movement jumps 3x per day (total ∼3 min/day). Controls were 71 matched children who followed usual school practice. We assessed dietary calcium, physical activity, physical performance, and anthropometry in September and after 8 months of intervention (June). We measured bone mineral content (BMC) and bone area at the lumbar spine, total body, and proximal femur. Proximal femur scans were also analysed for bone geometry and structural strength using the hip structural analysis program. Lean and fat mass (g) were also calculated. Results: Groups were similar at baseline and did not differ in weight, height, total body, lumbar spine, proximal femur, or femoral neck BMC. Control children had a greater increase in adjusted total body BMC (1.4%). Intervention children gained significantly more BMC at the total proximal femur (2%) and the intertrochanteric region (27%). Change in bone structural parameters did not differ between groups. Conclusions: This novel, easily implemented exercise program, took only a few minutes each day and enhanced bone mass at the weight bearing proximal femur in early pubertal children. A large, randomised study of boys and girls should be undertaken powered to test the effectiveness of Bounce at the Bell in children at different stages of maturity, and in boys and girls independently.     

Magnetic resonance perfusion and diffusion imaging characteristics of transient bone marrow edema,avascular necrosis and subchondral insufficiency fractures of the proximal femur

Purpose

To evaluate magnetic resonance (MR) perfusion and diffusion imaging characteristics in patients with transient bone marrow edema (TBME), avascular necrosis (AVN), or subchondral insufficiency fractures (SIF) of the proximal femur.

Materials and methods

29 patients with painful hip and bone marrow edema pattern of the proximal femur on non-contrast MR imaging were examined using diffusion-weighted and dynamic gadolinium-enhanced sequences. Apparent diffusion coefficients (ADCs) and perfusion parameters were calculated for different regions of the proximal femur. Regional distribution and differences in ADC values and perfusion parameters were evaluated.

Results

Seven patients presented with TBME, 15 with AVN and seven with SIF of the proximal femur. Perfusion imaging showed significant differences for maximum enhancement values (E_max), slope (E_slope) and time to peak (TTP) between the three patient groups (p < 0.05). In contrast, no significant differences for ADC values were calculated when comparing TBME, AVN, and SIF patients.

Conclusion

Diffusion weighted imaging of bone marrow of the proximal femur did not show significant differences between patients with TBME, AVN or SIF. In contrast, MR perfusion imaging demonstrated significant differences for the different patient groups and may as a complementary imaging technique add information to the understanding of the pathophysiology of diseases associated with bone marrow edema.     

Pediatric reference data for dual X-ray absorptiometric measures of normal bone density in the distal femur.

OBJECTIVE: Many children at risk for osteoporosis have substantial hip and knee contractures that prevent assessment of bone mineral density in the "usual" region, the proximal femur. As an alternative, bone density may be measured in the distal femur projected in the lateral plane. The purpose of this study was to provide normative reference data useful for interpretation of bone density measures in the distal femur of children and adolescents. SUBJECTS AND METHODS: The study was a cross-sectional, single-observational assessment of 256 healthy children and adolescents between the ages of 3 years and 18 years 6 months (mean, 10 years 5 months). Bone mineral density was measured in the nondominant proximal femur, lumbar spine, and both distal femurs using dual X-ray absorptiometry. RESULTS: We found that bone mineral density increases with age in the cortical, cancellous, and mixed regions of the distal femur, similar to the findings with other regional analyses of bone density. Bone density in the distal femur correlates very highly with bone density in the proximal femur and slightly less well with bone density in the lumbar spine. CONCLUSION: In pediatric patients who have deformities, have experienced trauma, or have undergone surgical procedures that prevent reliable measures of bone density in the proximal femur, bone mineral density may be measured in the distal femur and interpreted relative to the bone mineral density findings in healthy age- and sex-matched controls.     

女性髋部骨质疏松性骨折患者股骨近端几何结构对患者骨折危险的影响

目的研究女性髋部骨质疏松性骨折患者股骨近端几何结构对患者骨折危险的影响,以及股骨近端几何结构是否是独立于骨密度之外与髋骨骨折密切相关的危险因素。方法 2013年5月—2016年7月延安市人民医院骨科收治171例65周岁以上髋部骨质疏松性骨折女性患者(试验组,其中股骨颈骨折97例,股骨粗隆间骨折74例),另在同时期门诊收治65周岁以上骨质疏松症女性患者386例(对照组),采用双能X线吸收分析技术(DXA)分析比较这两组患者的骨密度(BMD)差异,并分析股骨近端几何结构与两种髋骨骨折之间的相关性。结果两组的体重、股骨颈横截面积(CSA)、股骨颈长(NL)、股骨颈宽与股骨近端骨密度差异有统计学意义(P0.05)。其中对照组股骨近端骨密度比试验组高(P0.05)。此外,在股骨颈骨折组中,股骨颈横截面积与股骨颈长骨折的比值比(OR)分别降低了1.98和1.72倍,而股骨颈宽骨折的OR增加了1.52倍;在粗隆间骨折组中,股骨颈宽骨折的OR则增加了1.44倍(P0.05),并且这些OR与股骨近端骨密度没有相关性。结论股骨颈宽是除骨密度以外独立的与女性髋骨骨折密切相关的危险因素。     

Magnetic resonance imaging findings of osteoid osteoma of the proximal femur

Osteoid osteoma (OO) is a benign bone tumor whose main radiological finding is nidus. OO of the proximal femur can also result in non-specific findings such as hip joint effusion, perinidal bone marrow edema and soft tissue mass. Since the nidus may be difficult to identify with MR, these non-specific findings can lead to erroneous diagnosis. Therefore, MR imaging technique should be optimized in order to identify nidus. Since MR imaging has assumed increasing importance in the evaluation of disorders of the hip, radiologists must be aware of the spectrum of findings of OO of the proximal femur. The aim of this pictorial review is to show the MR imaging findings of intra-articular and extra-articular OO of the proximal femur.     

Correlation of MRI and histomorphological findings in bone marrow oedema syndrome of the hip

Bone marrow oedema syndrome (BMOS) of the hip includes severe hip joint pain, focal loss of radiodensity in radiographs, increased uptake in bone scintigrams and the pattern of bone marrow oedema in the femoral heads in MRI scans. In 15 patients (16 hip joints) we found the clinical and radiological signs of BMOS. On T1-weighted MRI images areas of low signal intensity could be observed in the head, neck and the intertrochanteric region of the femur in various extensions. These areas showed a significant increase in signal intensity on the T2-weighted images. Because pain was resistant to conservative therapy all these patients were treated by core decompression of the femoral head in a prospective study. Bone cores were evaluated histologically using undecalcified sections and quantitative microradiography. The existence of intramedullary oedema in exactly the regions exhibiting the MRI pattern of bone marrow oedema was verified histologically; however, bone and marrow changes similar to those of early avascular necrosis (AVN) were also visible. These findings support our assumption that BMOS might be a transitory initial phase of AVN. Therefore core decompression treatment for patients suffering pain from BMOS is recommended after excluding other diseases.     

Proximal femur in biological profile estimation – Current knowledge and future directions

This review presents an overview of the forensic utilities of the proximal femur in the existing literature. The proximal epiphysis of the femur bone is characterized as a skeletal structure that articulates with an acetabulum of a pelvic bone, forming the hip joint and generally accounted for one-fourth of the whole femoral length. Features that are seen in proximal femora include femoral head, fovea capitis, neck, greater and lesser trochanters, and proximal shafts. These can be viable alternatives for assessing the following biological parameters: stature, sex, age, and ancestry. Therefore, if the proximal femur is the only skeletal element that is available for examination, all four of the constituent parts of a biological profile of an unknown individual can be retrieved from analyzing proximal femora using quantitative approaches.     

The importance of the location of fluorodeoxyglucose uptake in periprosthetic infection in painful hip prostheses

Ten per cent of patients with hip replacement will eventually complain of significant pain after surgery, often requiring a revision arthroplasty. The majority of these patients experience aseptic loosening rather than infection. Despite significant advances made in diagnostic imaging, distinguishing infection from aseptic loosening remains a significant challenge. Imaging using fluorodeoxyglucose (FDG) positron emission tomography (PET) has been reported to have excellent sensitivity in detecting infections associated with hip prostheses. However, in some studies, a high rate of false positive results has been reported, especially when increased tracer uptake adjacent to the prosthesis (which is not surrounded by bone) is used as the sole criterion for diagnosing infection. The objective of this investigation was to determine the optimal criteria for diagnosing periprosthetic infection, thereby avoiding false positive results in this setting. A total of 41 total hip arthroplasties from 32 patients and for whom complete clinical follow-up was available were included in this analysis. The location and intensity of FDG uptake were determined for each scan. Final diagnosis was made by microbiology, histopathology, surgical findings and clinical follow-up. Patients who did not undergo surgery were followed up to at least 9 months. Twelve patients were proven eventually to have periprosthetic infection. Images from 11 of these patients displayed increased tracer uptake along the interface between bone and prosthesis. The intensity of the increased tracer uptake varied from mild to moderate, with standardized uptake values less than 2. In contrast, images from uninfected, loose hip prostheses revealed very intense uptake around the head or neck of the prosthesis with standardized uptake values as high as 7. It is concluded that the intensity of increased FDG uptake is less important than the location of increased FDG uptake when FDG PET is used to diagnose periprosthetic infection in patients with hip arthroplasty. Using increased uptake as the sole criterion for diagnosing infection will result in false positive results in this setting.     

髋关节表面置换术后股骨近端及髋臼骨密度初步研究

目的 评价髋关节表面置换术（RSAH）对股骨近端及髋臼侧骨量的影响.方法 选择符合入组标准的单侧RSAH病人26例,于术后1年行髋关节手术侧及健侧的股骨近端和髋臼的骨密度检查,参考Taylor及Wilkinson方法分别将术后股骨近端及髋臼分为6个（1～6区）和3个（A1～A3）兴趣区,测量各兴趣区骨密度,用t检验对各区手术侧与健侧骨密度值进行比较.结果 手术侧的股骨近端5、6区的骨密度值大于健侧的,两者差异有统计学意义（P＜0.05）;1、2、3、4区的骨密度值在手术侧与健侧间的差异无统计学意义（P＞0.05）.髋臼侧全部区域中髋臼头侧（A1区）密度值,手术侧小于健侧,两者差异有统计学意义（P＜0.05）;手术侧与健侧的髋臼内侧及尾侧（A2、A3区）的骨密度比较,其差异无统计学意义（P＞0.05）.结论 关节表面置换术后股骨近端骨量可以得到有效保存和恢复,而髋臼侧骨质有丢失可能.     

New techniques for the diagnosis of osteoporosis

In this review article current developments and applications in quantitative osteoporosis imaging are presented. Developments in the field of DXA include geometrical parameters of the proximal femur such as the "hip axis length" and new ROIs to determine BMD. Advances in QCT are new volumetric techniques to quantify BMD at the lumbar spine and the proximal femur. In addition techniques to determine BMD in standard contrast-enhanced abdominal computed tomography studies are described. Currently with the new bone quality concept in full bloom techniques to quantify trabecular bone architecture as new surrogates of bone strength are of increasing significance. Spatial high-resolution techniques such as magnetic resonance imaging and new computed tomography techniques have shown their potential in assessing trabecular bone structure. In addition ultrasound is considered a low-cost technique to explore bone quality.     

Neue Techniken in der Osteoporosediagnostik

In this review article current developments and applications in quantitative osteoporosis imaging are presented. Developments in the field of DXA include geometrical parameters of the proximal femur such as the “hip axis length” and new ROIs to determine BMD. Advances in QCT are new volumetric techniques to quantify BMD at the lumbar spine and the proximal femur. In addition techniques to determine BMD in standard contrast-enhanced abdominal computed tomography studies are described. Currently with the new bone quality concept in full bloom techniques to quantify trabecular bone architecture as new surrogates of bone strength are of increasing significance. Spatial high-resolution techniques such as magnetic resonance imaging and new computed tomography techniques have shown their potential in assessing trabecular bone structure. In addition ultrasound is considered a low-cost technique to explore bone quality.     

Dynamic contrast-enhanced MR imaging assessment of vascularized free fibular grafts

Magnetic resonance (MR) imaging may be a noninvasive method for assessing perfusion of vascularized bone grafts placed for treatment of avascular necrosis. One proximal femur of seven beagles was devascularized, with insertion of a vascularized fibular graft. MR imaging at 1 week (seven dogs) and 6 weeks (five dogs) after surgery included pre- and postcontrast spin-echo sequences, unenhanced twodimensional time-of-flight (TOF) vascular imaging, and dynamic gradient-echo imaging during infusion of gadolinium. Relative signal intensity values of selected regions obtained from the dynamic gradientecho images were plotted as percent enhancement versus time. In the operated hip, MR imaging did not show enhancement in six of seven femoral heads and greater trochanters at 1 week after surgery, with similar results after 6 weeks. MR imaging of fibular grafts 6 weeks after surgery showed an initial rapid increase in enhancement and a subsequent slower increase in five of five dogs, although no enhancement was seen in six of seven dogs at 1 week. These findings contrasted with a rapid initial increase in enhancement followed by slow decline in non-operated hips. Two-dimensional TOP imaging did not show the vascular pedicle of the graft in any dog. Findings of radionuclide bone scanning performed 1 week after surgery were consistent with devascularization of the operated femur and fibular graft. However, tetracycline distribution and histologic findings confirmed the viability of five of five grafts within the devascularized femurs 6 weeks after surgery. Thus, dynamic contrast-enhanced MR imaging at 6 weeks after surgery is valuable for assessing vascular bone graft perfusion, while similar imaging at 1 week may suggest otherwise.     

Bone scintigraphy in preschool children with lower extremity pain of unknown origin.

Small children often cannot describe the location of bone pain for parents or physicians. Bone scans were performed in 56 children under five years of age with lower extremity pain and/or gait abnormalities of unknown etiology. Patients with fever, and those known to have infection, child abuse, malignancy, and/or radiographic abnormalities were excluded. Thirty patients had abnormal bone scans. Abnormalities included evidence of hip synovitis (4), femoral head avascularity (2), various proximal femoral abnormalities (3), knee synovitis (3), toddler's fracture (1), various tibial or fibular abnormalities (4), and various abnormalities of the tarsal bones (16). Tarsal bone abnormalities included four with abnormal calcaneal uptake and nine with abnormal uptake in or adjacent to the cuboid bone. Correlative imaging studies were available for 26 sites, and focal bone findings were noted at only five locations. Tarsal bone abnormalities accounted for over half of the scintigraphic abnormalities in these preschool children with gait abnormalities. Abnormal uptake in/or adjacent to the cuboid bone was common and probably represented stress injury.