Accurate model-based segmentation of gynecologic brachytherapy catheter collections in MRI-images

The gynecological cancer mortality rate, including cervical, ovarian, vaginal and vulvar cancers, is more than 20,000 annually in the US alone. In many countries, including the US, external-beam radiotherapy followed by high dose rate brachytherapy is the standard-of-care. The superior ability of MR to visualize soft tissue has led to an increase in its usage in planning and delivering brachytherapy treatment. A technical challenge associated with the use of MRI imaging for brachytherapy, in contrast to that of CT imaging, is the visualization of catheters that are used to place radiation sources into cancerous tissue. We describe here a precise, accurate method for achieving catheter segmentation and visualization. The algorithm, with the assistance of manually provided tip locations, performs segmentation using image-features, and is guided by a catheter-specific, estimated mechanical model. A final quality control step removes outliers or conflicting catheter trajectories. The mean Hausdorff error on a 54 patient, 760 catheter reference database was 1.49 mm; 51 of the outliers deviated more than two catheter widths (3.4 mm) from the gold standard, corresponding to catheter identification accuracy of 93% in a Syed–Neblett template. In a multi-user simulation experiment for evaluating RMS precision by simulating varying manually-provided superior tip positions, 3σ maximum errors were 2.44 mm. The average segmentation time for a single catheter was 3 s on a standard PC. The segmentation time, accuracy and precision, are promising indicators of the value of this method for clinical translation of MR-guidance in gynecologic brachytherapy and other catheter-based interventional procedures.     

Assertive rehabilitation for intracapsular fracture of the proximal femur

OBJECTIVE: To study the impact of assertive conservative therapy on walking in frail elderly patients with intracapsular fracture of the proximal femaur. DESIGN: Prospective non-randomized controlled trial. SETTING: Two private geriatric rehabilitation hospitals. SUBJECTS: From October 1997 to December 2004, 20 patients, not indicated for surgery, were treated with conservative therapy. There were 18 women and 2 men, and their ages were 87.1+/-4.2 (mean +/-SD) years. All of them could walk before hip fracture. INTERVENTIONS: Thirteen patients accepted our assertive therapy, which consisted of standing on the fractured limb and walking in parallel bars as soon as possible. Seven patients refused our methods and were conventionally treated; the injured limb was immobilized under skin traction, and then they gradually tried to use a wheelchair for pain reduction. MAIN MEASURES: We used the following measures before therapy and six months after: Merle d'Aubigné & Postel's Hip Score, Functional Independence Measure (FIM) and face pain scale. RESULTS: The two groups were similar demographically. All patients except one (n = 12) responded to our method and could walk. However, the patients treated with the conventional method (n = 7) did not recover the ability to walk. The mean FIM (transfer and locomotion, five items) was 18.2 +/-7.9 points in the former and 9.4 +/- 4.3 points in the latter. CONCLUSION: Assertive rehabilitation was more effective at restoring the ambulatory ability of frail elderly patients with intracapsular fracture of the hip than the conventional method.     

Rehabilitation after proximal femur fracture surgery in the oldest old

OBJECTIVE: To assess the course and results of rehabilitation after proximal femur fracture (PFF) in patients 85 years of age or older, compared with younger elderly patients, with an emphasis on functional status. DESIGN: Prospective cohort study. SETTING: A rehabilitation geriatric ward in a tertiary university hospital in southern Israel. PARTICIPANTS: The study group included 127 elderly patients 85 years of age or older who were hospitalized for rehabilitation following surgery for PFF. The comparison group was comprised of 297 patients aged 75 to 84 years who were hospitalized for the same indication in the same time period. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Functional studies by FIM trade mark instrument, mental status by the Folstein Mini-Mental State Examination, Geriatric Depression Screening (GDS) scale, length of rehabilitation, and complications and mortality during rehabilitation. RESULTS: Compared with patients aged 75 to 84 years, the older study group was in a worse mental state (P=.00005), even though the groups did not differ in their GDS scores. There were no significant differences between the groups in rehabilitation length of stay, in the rate of most postoperative complications, or in death rates during rehabilitation. FIM values before PFF, at the beginning of rehabilitation and at its end, and the difference between the beginning and end of rehabilitation were lower in the older group (P<.00001 for all tests). CONCLUSIONS: From the functional standpoint, rehabilitation after PFF surgery is much less successful in the 85+ age group than in the 75-to-84 age group but did not differ in its duration, rates of most complications, or mortality. Nonetheless, a significant percentage of patients in this age group have successful rehabilitation so they should not be deprived the chance.     

股骨近端纤维结构不良的外科治疗及进展

纤维结构不良是一种非遗传性的骨发育障碍性疾病,与染色体20基因位点上编码Gs蛋白等的基因突变有关。多数病变为单发性,股骨近端及头面部骨是最常受累部位,临床主要表现为病变部位的疼痛、畸形和病理性骨折。为了确切有效地治疗病灶、降低复发,尽可能预防诊治病理性骨折及畸形,一般以手术作为主要的治疗方案,文中就股骨近端纤维结构不良的外科治疗及研究进展作一综述。     

Increased bone resorption in the proximal femur in patients with hemiplegia

OBJECTIVES: To investigate the relationship between the proximal femoral bone mineral density and bone resorption markers, determinants of calcium metabolism and vitamin D levels in elderly stroke patients. DESIGN: A total of 80 patients and 20 controls were enrolled in the study. Bone mineral density measurements were obtained at the proximal femur. In all subjects, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, intact parathyroid hormone, osteocalcin, deoxypyridinoline, and ionized calcium concentrations were measured. Barthel Index and Motricity Index Leg Score were recorded all patients. RESULTS: The serum concentrations of deoxypyridinoline, intact parathyroid hormone, and the mean serum ionized calcium levels were significantly higher in patients with stroke than that of the control subjects. The mean serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D concentrations in patients were significantly lower than those of the control group (P < 0.05). The bone mineral density of proximal femurs of paretic limbs was decreased significantly compared with those of the control group (P < 0.05). There were significant correlations between the Z score of the hemiplegic side and the patients' Barthel Index, Motricity Index Leg Score, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, calcium, and deoxypyridinoline. CONCLUSIONS: This study provides clear evidence that decreased mobility, vitamin D status, and bone turnover variables in patients after stroke are important factors in the greater bone loss in the paretic leg.     

Osteosynthesis of the proximal femur anchorage of a cervical nail

One of the factors determining the stability of osteosynthesis is the mechanical strength of the bone fragments required for the anchorage of the implant. The aim is to study the driving of a Thornton nail in the proximal epiphysis of a human femur as a way to measure the strength of the trabecular bone and to predict the stability of the implanted system.     

The architecture of the proximal femur: an imaging analysis

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

The application of computer assistance in planning osteotomy of the proximal femur

Background. The aim of this article is to demonstrate the capabilities of the SCFEanalyzer computer program, which may be helpful in preoperative planning of osteotomy of the proximal femur. Material and methods. Computed tomography scans were performed on human bone specimens: one pelvis and two femoral bones (right and left). The CT data were used to demonstrate the abilities of our SCFEanalyzer software, which utilizes three-dimensional virtual models of anatomic structures constructed from these data. The software enables qualitative and quantitative spatial analysis of chosen parameters analogous to those done on the basis of plain radiographs. SCFEanalyzer makes it possible to evaluate the function of the hip joint by calculating the range of motion depending on the shape of bone structures. On the basis of the analysis of femoral geometry and function of the hip joint, it is possible to plan and simulate osteotomy of the proximal femur on the computer screen. Analogous qualitative and quantitative evaluation after performing the virtual surgery enables its potential effects to be assessed. Conclusions. The use of computer assistance in preoperative planning enable us to increase objectivity and repeatability, and to compare the results of different types of osteotomy of the proximal femur, and thus to choose the optimal operation in each individual case.     

Diseases of proximal femur segment in subjects of working age

A high-energy injury in subjects under the age of 50 as a rule leads to hip dislocation. This condition requires urgent orthopedic aid to avoid the risk of femur head osteonecrosis. Given a failure of closed reduction of dislocation (to be performed within 6 hours after the injury), immediate open reduction is indicated. The surgical approach depends on the dislocation type. The Kocher-Langenbeck approach is practiced to treat posterior dislocation and the Smith-Petersen or Watson-Jones approach in case of anterior dislocation. The most frequent and dangerous complications are femur head osteonecrosis (in 4-22% of the cases even after timely reduction) and post-traumatic coxarthrosis. Osteonecrosis is managed by a variety of surgical methods, viz. central decompresson, osteoplasty, corrective osteotomy, endoprosthetics. Its late stages, with sclerosis affecting over 30% of the head surface, are treated by resurfacing arthroplasty, hemiarthroplasty, total surface arthroplasty, uni- and bipolar hemiarthroplasty, total endoprosthetics, and administration of expanded stem cells into the subchondrial layer. The use of tissue-engineering technologies for the treatment of osteonecrosis is not confined to the treatment of its precollaptoid stages. They can be employed to promote osteointegration at the metal-bone interface and thereby to improve secondary stability or prolong the hardware lifetime.     

Wavelet-based signal processing of in vitro ultrasonic measurements at the proximal femur

To estimate osteoporotic fracture risk, several techniques for quantitative ultrasound (QUS) measurements at peripheral sites have been developed. As these techniques are limited in the prediction of fracture risk of the central skeleton, such as the hip, we are developing a QUS device for direct measurements at the femur. In doing so, we noticed the necessity to improve the conventional signal processing because it failed in a considerable number of measurements due to multipath transmission. Two sets of excised human femurs (n = 6 + 34) were scanned in transmission mode. Instead of using the conventional methods, the radio-frequency signals were processed with the continuous wavelet transform to detect their time-of-flights for the calculation of speed-of-sound (SOS) in bone. The SOS-values were averaged over a region similar to the total hip region of dual X-ray absorptiometry (DXA) measurements and compared with bone mineral density (BMD) measured with DXA. Testing six standard wavelets, this algorithm failed for only 0% to 6% of scan in test set 1 compared with 29% when using conventional algorithms. For test set 2, it failed for 2% to 12% compared with approximately 40%. SOS and BMD correlated significantly in both test sets (test set 1: r2 = 0.87 to 0.92, p < 0.007; test set 2: r2 = 0.68 to 0.79, p < 0.0001). The correlations are comparable with correlations recently reported. However, the number of evaluable signals could be substantially increased, which improves the perspectives of the in vivo measurements.     

股骨近段髓腔的CT测量及股骨假体设计

背景：人工关节大多根据西方人种设计,与国人股骨近段髓腔存在一定差异。目的：通过CT测量股骨近段横断面的髓腔内径参数,为设计符合国人的髋关节假体提供数据。方法：通过CT对61例初次行全髋关节置换成年人的健侧股骨近段进行扫描,连续扫描3层,层厚均2mm,测量股骨颈平面、股骨小转子平面、股骨峡部平面的髓腔内径等参数。结果与结论：股骨峡部平面的各径线之间、股骨颈平面的宽径与内侧径之间、股骨小转子平面的长径与内侧径之间都存在着显著相关性（P〈0.05）。股骨颈平面的长径、宽径、内侧径及股骨峡部平面的皮质厚度在男女之间差异具有显著性意义（P〈0.05）。所测3个平面的径线可为该类型股骨假体的设计提供数据支持。     

股骨近段髓腔的CT测量及股骨假体设计

背景:人工关节大多根据西方人种设计,与国人股骨近段髓腔存在一定差异.目的:通过CT测量股骨近段横断面的髓腔内径参数,为设计符合国人的髋关节假体提供数据.方法:通过CT对61例初次行全髋关节置换成年人的健侧股骨近段进行扫描,连续扫描3层,层厚均2 mm,测量股骨颈平面、股骨小转子平面、股骨峡部平面的髓腔内径等参数.结果与结论:股骨峡部平面的各径线之间、股骨颈平面的宽径与内侧径之间、股骨小转子平面的长径与内侧径之间都存在着显著相关性(P < 0.05).股骨颈平面的长径、宽径、内侧径及股骨峡部平面的皮质厚度在男女之间差异具有显著性意义 (P < 0.05).所测3个平面的径线可为该类型股骨假体的设计提供数据支持.     

股骨近端肿瘤性骨缺损的修复重建

目的探讨股骨近端肿瘤性骨缺损的有效修复方法.方法股骨头、颈及转子间部肿瘤共38例,根据肿瘤的生物学行为及瘤灶大小分别采用病灶刮除+异体皮松质骨植入13例,病灶刮除+异体皮松质骨、自体缝匠肌髂骨瓣复合植入18例,病灶刮除+载阿霉素骨水泥6例;瘤段切除+人工股骨头置换1例.结果术后随访14～48个月,平均26个月,仅1例局部复发,功能评分34例为优,4例为良.结论依据肿瘤生物学行为和原理对其进行了治疗功能重建,是一套行之有效的重建股骨近端肿瘤性骨缺损的方案.     

Do osteotomies of the proximal femur still have a role?

Trochanteric valgus and varus correction osteotomies have been described with or without associated rotational correction. In the last decade, new techniques have been described, including femoral neck osteotomy, femoral head reorientation, relative neck lengthening, greater or lesser trochanter distalization, and femoral head reduction osteotomy. While the overall number of femoral osteotomies in the young patients has decreased because of the efficacy of primary total hip arthroplasties, those osteotomy techniques may expand the indications for femoral osteotomies in select patients who meet the indications.     

In vivo measurements of ultrasound transmission through the human proximal femur

Quantitative ultrasound (QUS) measurements can be used to estimate osteoporotic fracture risk. The commonly used variables are the speed of sound (SOS) and the frequency dependent sound attenuation (broadband ultrasound attenuation, [BUA]) of a wave propagating through the bone, preferably the calcaneus. The technology, so far, is less suitable for direct measurement in vivo at the spine or the femur for prediction of bone mineral density (BMD) or fracture risk at the main osteoporotic fracture sites. To improve the clinical performance of QUS, we built a device for direct QUS measurements at the human femur in vivo. In vivo images of ultrasound transmission at one of the main fracture sites, the proximal femur, could be acquired. The estimated precision of SOS measurements of 0.5% achieved at the femur is comparable with the precision of peripheral QUS devices.     

全髋股骨侧假体置入前倾角对股骨上段应力分布的影响

背景股骨侧假体置换时按照原前倾角置入假体是公认的做法,但目前并无严格的生物力学实验证明其合理性.目的验证以不同前倾角置入股骨侧假体对股骨上段应力分布的影响.设计随机分组、相互对照的实验研究.地点和对象吉林大学机械学院力学系;15件新鲜成人股骨标本(自愿捐献).干预将15件标本随机分为3组,每组5件标本,对3组分别以原前倾角,+15°(在原前倾角的基础上再前倾15°),+30°前倾角置入非骨水泥固定假体,对置换前后的试件分别施以轴向载荷及复合载荷(轴向载荷+扭转载荷).主要观察指标置换前后各试件各点的应变值.结果轴向载荷下的应变分布规律,在小转子上缘以下105 mm外方3组间差异有显著性意义,以原前倾角组应变最大(平均166.08%),+30°组次之(平均121.24%),+15°组最小(平均105.40%),以较原前倾角大约15°的角度置入全髋股骨侧假体与以原前倾角置入假体相比会使更多的应力经股骨近端传导,其股骨表面的应变分布最接近于未处置股骨.结论以+15°前倾角置入假体会获得最佳的近端匹配,使置换后股骨获得更多的近端承载,有效降低应力遮挡,有利于骨长入及远期稳定.     

股骨头缺血性坏死对股骨近端骨组织的影响

背景股骨头缺血坏死可导致患者运动功能障碍,常用的治疗方法是全髋关节置换术,但手术失败原因目前尚不清楚.有作者认为是股骨近端骨组织异常所至,但是缺乏深入研究.目的探讨股骨头缺血坏死患者的股骨近端骨改变.设计以患者为研究对象,非随机化同期对照研究.单位青岛大学医学院附属医院创伤外科.对象1999-09/2003-05青岛大学医学院创伤外科收治的股骨头缺血坏死患者18例,男12例,女6例;平均年龄(50±5)岁.同期骨关节炎患者18例,男10例,女8例;平均年龄(62±3)岁.方法对18例股骨头缺血坏死行全髋关节置换术患者的股骨头和股骨近端松质骨标本进行组织学检查,并用18例髋关节骨关节炎患者作为对照组,所有标本采用双盲方式进行检查.主要观察指标两组患者股骨颈、大转子、小转子、股骨干的坏死评分和坏死阳性率.结果股骨头缺血坏死患者小转子下方4 cm处存在广泛的骨坏死.股骨头缺血坏死组和对照组坏死评分总分分别为82分和16分;坏死阳性率分别为63.89%和19.44%,两组之间股骨近端的骨坏死程度相比较差异有非常显著性意义(P＜0.001).结论股骨近端的骨改变可能是股骨头缺血坏死行全髋关节置换早期失败的原因之一.     

Validation of postural radiographs as a way to measure change in pelvic obliquity

OBJECTIVE: To evaluate the validity of using postural radiographs to assess change in pelvic obliquity. DESIGN: Blinded comparison of reference lines and instrument development of postural radiographs. SETTING: Veterans Administration hospital. PARTICIPANTS: Thirty-nine subjects with no history of low back pain. INTERVENTION: Repeated postural radiographs without heel lifts and with (1/4)-in (6.35-mm) and (1/2)-in (12.7-mm) heel lifts. MAIN OUTCOME MEASURE: The change of pelvic obliquity as measured by the intersulcate, interalar, and sacral surface lines on postural radiographs. RESULTS: A (1/4)-in heel lift resulted in changes of 4.6+/-4.0mm, 3.6+/-3.1mm, and 5.8+/-3.9mm and a (1/2)-in heel lift in changes of 7.8+/-4.3mm, 7.8+/-4.6mm, and 5.2+/-3.8mm for the intersulcate, interalar, and sacral surface lines, respectively. Pearson correlation coefficients were used to correlate the change in pelvic obliquity with the corresponding heights of heel lifts; for the (1/4)-in heel lift, they were.67,.88, and.71, and for (1/2)-in heel lift they were.73,.79, and.87 for the intersulcate, interalar, and sacral surface lines, respectively (all P<.001). CONCLUSION: All the reference lines seem to be valid measures of change of pelvic obliquity relative to the size of the lifts (ie, the changes in pelvic obliquity seem to be causally related and correlated with the lifts). These results also suggest that postural radiographs can be used to determine the magnitude of pelvic obliquity.     

股骨近段CT扫描与全髋关节置换的术前计划

背景：做好全髋关节置换前假体型号预测的前提是对股骨近段的充分了解和精确测量,但X射线片仅提供一个平面图像,不能了解股骨近段横断面的情况,而股骨上段CT扫描可以提供更多信息。目的：观察股骨近段CT扫描在全髋关节置换前计划中的作用。方法：对61例进行初次全髋关节置换的患者行股骨近端CT扫描,选取股骨小转子最突出处上方2cm股骨颈平面（T20）、股骨小转子最突出点处的股骨转子区平面（T0）和股骨干髓腔最狭窄处平面（N）的横断面CT影像。测量股骨颈平面髓腔长径、宽径、内侧径;小转子平面髓腔长径、内侧径;股骨峡部平面髓腔长径、宽径、皮质厚度。结果与结论：股骨颈T20长径40.8～63.3mm,平均（49.6±5.1）mm;T20宽径13.3～29.1mm,平均（22.4±3.4）mm;T20内侧径7.2～14.6mm,平均（10.6±1.6）mm。股骨转子区T0长径20.5～40.2mm,平均（28.7±4.4）mm;T0内侧径4.3～13.0mm,平均（8.1±1.7）mm。股骨峡部N长径8.2～22.4mm,平均（14.1±3.1）mm;N宽径6.1～17.9mm,平均（10.2±2.9）mm;N皮质厚度2.7～12.7mm,平均（7.5±1.8）mm。提示股骨近端CT扫描可以提供更多的影像信息和更精确的测量数据,对全髋关节置换前计划有所帮助。