Computed Tomography

The primary goal of this research was to provide image processing support to aid in the identification of those subjects most affected by bone loss when exposed to weightlessness and provide insight into the causes for large variability. Past research has demonstrated that genetically distinct strains of mice exhibit different degrees of bone loss when subjected to simulated weightlessness. Bone loss is quantified by in vivo computed tomography (CT) imaging. The first step in evaluating bone density is to segment gray scale images into separate regions of bone and background. Two of the most common methods for implementing image segmentation are thresholding and edge detection. Thresholding is generally considered the simplest segmentation process which can be obtained by having a user visually select a threshold using a sliding scale. This is a highly subjective process with great potential for variation from one observer to another. One way to reduce inter-observer variability is to have several users independently set the threshold and average their results but this is a very time consuming process. A better approach is to apply an objective adaptive technique such as the Riddler / Calvard method. In our study we have concluded that thresholding was better than edge detection and pre-processing these images with an iterative deconvolution algorithm prior to adaptive thresholding yields superior visualization when compared with images that have not been pre-processed or images that have been pre-processed with a filter.

Introduction: Haemophilia A, patients often give a history of unusual bleeding associated with minor trauma or surgical procedures. Iliopsoas pseudotumour is a serious complication of undiagnosed haemophilia, which may follow a trivial procedure. Case presentation: We present a 20-year-old male patient with a six-month history of left leg weakness and limitation of movement. Clinically he was diagnosed as having a psoas muscle rhabdomyosarcoma. Later proofed to be haemophilic pseudotumour (HP). Conclusion: Progressively enlarging masses in the pelvis of a person with haemophilia should raise the suspicion of a pseudotumour. The presence of a muscle mass in the pelvis or limb should be properly investigated and should raise the suspicion of haemophilia.

Background: Spontaneous pneumothorax may result from rupture of subpleural blebs. Computed tomography (CT) has been used to identify blebs to serve as an indication for thoracoscopy. We reviewed our experience with spontaneous pneumothorax to assess the utility of CT in these patients. Methods: A retrospective review was conducted of all patients who underwent an operation for spontaneous pneumothorax from January 1999 to October 2009. All procedures were performed thoracoscopically. Results: We identified 39 pneumothoraces in 34 patients who underwent evaluation and a procedure for spontaneous pneumothorax. Mean age was 16.1 years (range, 10-23 years), with an average of 1.7 spontaneous pneumothoraces before operation (range, 1-4). Preoperative chest CT scans were obtained in 26 cases. Blebs were demonstrated on 8 CT scans. The presence of blebs was confirmed at operation in all 8 patients. Of the 18 negative scans, 14 (77.8%) were found to have blebs intraoperatively, 7 of these patients were initially managed nonoperatively and developed recurrence. The sensitivity of CT for identifying blebs was 36%. Conclusions: Chest CT does not appear to be precise in the identification of pleural blebs and a negative examination does not predict freedom from recurrence. Operative decisions should be based on clinical judgment without the use of preoperative CT.

Biopsy of the musculoskeletal system is useful in the management of bone lesions particularly in oncology but they are often challenging procedures with a significant risk of complications. Computed tomography (CT)-guided needle biopsies may decrease these risks but doubts still exist about their diagnostic accuracy. This retrospective analysis of the experience of a single institution with percutaneous CT-guided biopsy of musculoskeletal lesions evaluates the results of these biopsies for bone lesions either in the appendicular skeleton or in the spine, and defines indications. We reviewed the results of 2027 core needle biopsies performed over the past 18 years at the authors' institution. The results obtained are subject of this paper. In 1567 cases the correct diagnosis was made with the first CT-guided needle biopsy (77.3% accuracy rate), in 408 cases the sample was not diagnostic and in 52 inadequate. Within 30 days these 408 patients underwent another biopsy, which was diagnostic in 340 cases with a final diagnostic accuracy of 94%. Highest accuracy rates were obtained in primary and secondary malignant lesions. Most false negative results were found in cervical lesions and in benign, pseudotumoral, flogistic, and systemic pathologies. There were 22 complications (18 transient paresis, 3 haematomas, 1 retroperitoneal haematoma) which had no influence on the treatment strategy, nor on patient outcome. This technique is reliable and safe and should be considered nowadays the gold standard for biopsies of the musculoskeletal system.

In this randomized, double-blind, placebo-controlled 12-month trial we evaluated effects of weight-bearing jumping exercise and oral alendronate, alone or in combination, on the mass and structure of bone, risk factors for falling (muscle strength and power, postural sway, and dynamic balance), and cardiorespiratory fitness in postmenopausal women. A total of 164 healthy, sedentary, early postmenopausal women were randomly assigned to one of four experimental groups: (1) 5 mg of alendronate daily plus progressive jumping exercise, (2) 5 mg alendronate, (3) placebo plus progressive jumping exercise, or (4) placebo. The primary endpoint was 12-month change in bone mass and geometry (measured with dual-energy X-ray absorptiometry and peripheral computed tomography at several axial and limb sites) and physical performance; the secondary endpoint was change in biochemical markers of bone turnover. The jumping exercise was conducted an average 1.6 Ϯ 0.9 (mean Ϯ SD) times a week. Alendronate daily was effective in increasing bone mass at the lumbar spine (alendronate vs placebo 3.5%; 95% CI, 2.2-4.9%) and femoral neck (1.3%; 95% CI, 0.2-2.4%) but did not affect other bone sites. Exercise alone had no effect on bone mass at the lumbar spine or femoral neck; it had neither an additive nor an interactive effect with alendronate at these bone sites. However, at the distal tibia the mean increase of 3.6% (0.3-7.1%) in the section modulus (that is, bone strength) and 3.7% (0.1-7.3%) increase in the ratio of cortical bone to total bone area were statistically significant in the exercise group compared to the nonexercise group, indicating exercise-induced thickening of the bone cortex. Bone turnover was reduced in alendronate groups only. Alendronate had no effect on physical performance while the jumping exercise improved leg extensor power, dynamic balance, and cardiorespiratory fitness. As conclusion Alendronate is effective in increasing bone mass at the lumbar spine and femoral neck, while exercise is effective in increasing the mechanical properties of bone at some of the most loaded bone sites, as well as improving the participants' muscular performance and dynamic balance. Together alendronate and exercise may effectively decrease the risk of osteoporotic fractures.