Preoperative assessment of bone density for dental implantation: a comparative study of three different ROI methods.

BACKGROUND: Dental cone beam computed tomography (CBCT) is commonly used to evaluate cancellous bone density before dental implant surgery. However, to our knowledge, no measurement approach has been standardized yet. This study aimed to evaluate the relationship between three different regions of interest (ROI) methods on cancellous bone density at the dental implant site using dental CBCT images. METHODS: Patients' dental CBCT images (n = 300) obtained before dental implant surgery were processed using Mimics (Materialise, Leuven, Belgium). At the potential implant sites, the rectangle, cylinder, and surrounding cylinder ROI methods were used to measure bone density. Repeated measures one-way analysis of variance was performed to compare the three ROI methods in terms of measurement results. Pearson correlation analysis was performed to identify the likely pair-wise correlations between the three ROI methods. RESULTS: The density value obtained using the surrounding cylinder approach (grayscale value [GV],523.56 ± 228.03) was significantly higher than the values obtained using the rectangle (GV, 497.04 ± 236.69) and cylinder (GV,493 ± 231.19) ROI methods in terms of results. Furthermore, significant correlations were noted between the ROI methods (r > 0.965; p < 0.001). CONCLUSIONS: The density measured using the surrounding cylinder method was the highest. The choice of method may not influence the trends of measurement results. TRIAL REGISTRATION: This study was approved by the Institutional Review Board of China Medical University Hospital, No. CMUH111-REC3-205. Informed consent was waived by the Institutional Review Board of China Medical University Hospital, CMUH111-REC3-205, owing to the retrospective nature of the study.

Chronic high-dose testosterone impairs economic decision making, but has no effect on memory in male rats.

The goal is to understand consequences of anabolic-androgenic steroid (AAS) abuse on cognitive function, using rats as a model. Economic decision making was evaluated in an operant test of effort value discounting, where subjects choose between 2 levers that deliver large and small rewards differing in maximum value and reward contrast. The hypothesis is that chronic high-dose testosterone increases preference for large rewards. Male rats were treated chronically with testosterone (7.5 mg/kg) or vehicle. Initially, all rats preferred the large reward lever when large and small rewards remained fixed at 3 and 1 sugar pellets, respectively. When different reward values were introduced, and with increasing response requirements, testosterone-treated rats made fewer responses for the large reward, and increased omissions. They earned fewer rewards overall. To determine if testosterone impairs memory, rats were tested for recognition memory with the novel object recognition and social transmission of food preference tasks, and for spatial memory with the radial arm maze and Morris water maze. There was not effect of chronic high-dose testosterone on any memory task. These results suggest that testosterone shifts economic decision making towards larger rewards even when they are disadvantageous, but does not alter memory in rats.

Multi-colour extrusion fused deposition modelling: a low-cost 3D printing method for anatomical prostate cancer models.

Three-dimensional (3D) printed prostate cancer models are an emerging adjunct for urological surgical planning and patient education, however published methods are costly which limits their translation into clinical practice. Multi-colour extrusion fused deposition modelling (FDM) can be used to create 3D prostate cancer models of a quality comparable to more expensive techniques at a fraction of the cost. Three different 3D printing methods were used to create the same 3D prostate model: FDM, colour jet printing (CJP) and material jetting (MJ), with a calculated cost per model of USD 20, USD 200 and USD 250 respectively. When taking into account the cost, the FDM prostate models are the most preferred 3D printing method by surgeons. This method could be used to manufacture low-cost 3D printed models across other medical disciplines.

Direct mailing was a successful recruitment strategy for a lung-cancer screening trial.

OBJECTIVE: To analyze advertising, recruitment methods, and study participant demographics for the National Lung Screening Trial (NLST) site at Wake Forest University School of Medicine to define efficient ways to recruit participants for general clinical trials. STUDY DESIGN AND SETTING: Recruitment method data, demographics, geographic location, and date of enrollment were collected from all 1,112 NLST participants. Marketing data and financial records were analyzed to determine the effectiveness of each recruitment method. RESULTS: The total amount spent on advertising was $144,668, with the cost of enrollment per participant averaging $130. For black participants, the recruitment cost per person was $406, whereas for white and other race participants, the cost was $122 (P<0.0001). To encourage minority enrollment, $13,192 was spent on television advertising geared toward black viewers, resulting in eight black participants at an average cost per person of $1,649. Direct mailing cost $143 per participant recruited, whereas TV ads cost $382 per participant. CONCLUSION: Direct mailing to a targeted group was the most efficient way to recruit participants. Printed advertising methods, that is, newspaper ads and brochures, were quite effective, whereas television ads were expensive. Appropriate minority recruitment needs sufficient attention and resources to ensure census groups are adequately represented.

Noninvasive assessment of portomesenteric venous thrombosis: current concepts and imaging strategies.

Rapid, noninvasive imaging strategies, especially multidetector spiral CT and CT angiography (CTA) as well as gadolinium-enhanced MR angiography (MRA), have facilitated early diagnosis of splanchnic venous thrombosis, a potentially lethal cause of intestinal ischemia. Single breath-hold volumetric acquisitions permit superior temporal and contrast resolution while eliminating motion artifact and suppressing respiratory misregistration. Increased spatial resolution is aided by thinner slice collimation. These cross-sectional imaging techniques are becoming a preferred noninvasive alternative to conventional selective mesenteric angiography with delayed imaging for venous evaluation and should be considered the primary diagnostic modalities for evaluating patients with high clinical suspicion of nonsurgical mesenteric ischemia.