The receiver operating characteristic (ROC) curve, which is defined as a plot of test sensitivity as the y coordinate versus its 1-specificity or false positive rate (FPR) as the x coordinate, is an effective method of evaluating the performance of diagnostic tests. The purpose of this article is to provide a nonmathematical introduction to ROC analysis. Important concepts involved in the correct use and interpretation of this analysis, such as smooth and empirical ROC curves, parametric and nonparametric methods, the area under the ROC curve and its 95% confidence interval, the sensitivity at a particular FPR, and the use of a partial area under the ROC curve are discussed. Various considerations concerning the collection of data in radiological ROC studies are briefly discussed. An introduction to the software frequently used for performing ROC analyses is also presented.
Area Under Curve ; Coin Lesion, Pulmonary/radiography ; Human ; *ROC Curve ; Radiography/*statistics & numerical data ; Software ; Statistics, Nonparametric

OBJECTIVETo study the interobserver variation and its sources in classifying chest radiographs of pneumoconiosis for improving diagnostic quality.

METHODSA set of 240 high-voltage chest radiographs including different stages of pneumoconiosis was developed and 5 sets of copies were made in the same condition. It was read by 7 experienced readers independently in eligible situation. Results of reading were recorded in unified reading sheets. The profusion of small opacities and the stage of pneumoconiosis were recorded as corresponding numerical value for analysis.

RESULTSThe coefficients of variation of 7 readers in total profusion of small opacities, average profusion of small opacities and stage of pneumoconiosis were 15.17%, 15.91%, 12.06%, respectively. The judgement of the presence or absence of small opacities, large opacities and coalescence of small opacities were closer, and the rates of consistency were 91.09%, 91.93% and 76.41% respectively. Technical quality of the radiographs in this study could not make a considerable impact on the reading results. If the shape of small opacities were recorded consistently by most readers as small rounded opacities or small irregular opacities, the judgement of total profusion of small opacities and stage of pneumoconiosis were more consistent; if the shape of small opacities were recorded inconsistently, the difference of judgement was higher.

CONCLUSIONInterobserver variation exists actually among different readers and the main sources of the variation come from uncertain judgement of the shape of small opacities.

To improve the manufacturer's medical equipment after-sale service, the fifth Shanghai zone customer satisfaction survey was launched by the end of 2011. The DSA/X-ray equipment was setup as an independent category for the first time. From the survey we can show that the DSA/X-ray equipment's CSI is higher than last year, the customer satisfaction scores of preventive maintenance and service contract are lower than others, and CSI of local brand is lower than imported brand.
Consumer Behavior ; Product Surveillance, Postmarketing ; statistics & numerical data ; Quality Control ; Radiography ; instrumentation ; standards

BACKGROUND: This study was performed to investigate the relationship between coronal computed tomography (CT) and Broden's view in terms of location of the fracture line and fracture pattern. METHODS: Forty-five feet of 45 patients with intraarticular calcaneal fractures were evaluated. The mean age of the patients was 46.3 years (standard deviation, 18.1; range, 15 to 80 years), and there were 34 men and 11 women. The Broden's views were acquired using the ray sum projection, reviewed, and correlated with the coronal CT image to determine the location of the fracture on the posterior facet and fracture pattern described by the Sanders classification. The quantified location of the fracture line was defined as the distance between the medial margin of posterior facet and the fracture line divided by the whole length of the posterior facet, which was expressed as a percentage. RESULTS: The fracture line on the Broden's view was positioned at 22.3% (standard deviation, 29.6) laterally compared to that on coronal CT (p < 0.01). Although all cases showed posterior facet involvement on the CT scan, the fracture line was positioned lateral to the posterior facet in 6 cases (13.3%) in the Broden's view. The coronal CT and Broden's view showed a low level of agreement in the fracture pattern according to the Sanders classification, with kappa values of 0.23. CONCLUSIONS: Surgeons should consider that the fracture line on the Broden's view shows positioning laterally compared to coronal CT and they should consider that the fracture line at the lateral to posterior facet on the Broden's view might be an intraarticular fracture line. There are some limitations when applying the Sanders classification with the Broden's view.
Adolescent ; Adult ; Aged, 80 and over ; Calcaneus/*injuries/*radiography ; Female ; Foot Injuries/*radiography ; Fractures, Bone/*radiography ; Humans ; Intra-Articular Fractures/*radiography ; Male ; Middle Aged ; Patient Positioning/*methods ; Retrospective Studies ; Statistics, Nonparametric ; Tomography, X-Ray Computed/*methods

BACKGROUND: Not much is known regarding avulsion fractures of the calcaneal tuberosity. We propose a modified classification scheme that presents the four types of calcaneal avulsion fracture as described by surgical and magnetic resonance imaging (MRI) findings, and evaluation of their specific features. METHODS: Out of 764 cases of calcaneal fractures, we examined 20 cases (2.6%) that involved the tuberosity of the calcaneus. Each case was classified depending on the avulsed fracture patterns as follows; type I is a 'simple extra-articular avulsion' fracture, type II is the 'beak' fracture, type III is an infrabursal avulsion fracture from the middle third of the posterior tuberosity, and finally in type IV there is the 'beak', but a small triangular fragment is separated from the upper border of the tuberosity. We examined the features of each avulsed type according to several criteria including patient age, gender, anatomical variances of the Achilles tendon, the fibers involved and the mechanism of injury. RESULTS: The type I fracture (8/20 cases) was the most common and likely to occur in elderly women. However, in other types, they were more common in relatively younger male patients. Type I were usually caused due to an accidental trip causing a fall by the patient. However, the dominant cause of type II (5/20 cases) fractures a direct blow or hit directly to the bone. Type III (4/20 cases) and IV (3/20 cases) fractures were likely to occur due to falling. All fibers within the Achilles tendon are involved in both type I and II fractures. However, only the superficial fibers are involved in type III fractures, whereas the deep fibers are involved in type IV fractures. CONCLUSIONS: The avulsion patterns of the calcaneal tuberosity fractures are the result of several factors including the bony density level, the mechanism of injury and the fibers of the Achilles tendon that transmit the force. Accurate diagnosis of type III and IV is dependant on MRI technology to confirm the specific location of the injury and provide proper patient treatment therapeutics.
Adolescent ; Adult ; Age Factors ; Aged ; Calcaneus/*injuries/pathology/radiography ; Child ; Female ; Fractures, Bone/*classification/pathology/radiography ; Humans ; Male ; Middle Aged ; Statistics, Nonparametric

BACKGROUND/AIMS: Currently, the videofluoroscopic swallowing study (VFSS) is the standard tool for evaluating dysphagia. We evaluated whether the addition of endoscopist-directed flexible endoscopic evaluation of swallowing (FEES) to VFSS could improve the detection rates of penetration, aspiration, and pharyngeal residue, compared the diagnostic efficacy between VFSS and endoscopist-directed FEES and assessed the adverse events of the FEES. METHODS: In single tertiary referral center, a retrospective analysis of prospectively collected data was conducted. Fifty consecutive patients suspected of oropharyngeal dysphagia were enrolled in this study between January 2012 and July 2012. RESULTS: The agreement in the detection of penetration and aspiration between VFSS and FEES of viscous food (kappa=0.34; 95% confidence interval [CI], 0.15 to 0.53) and liquid food (kappa=0.22; 95% CI, 0.02 to 0.42) was "fair." The agreement in the detection of pharyngeal residue between the two tests was "substantial" with viscous food (kappa=0.63; 95% CI, 0.41 to 0.94) and "fair" with liquid food (kappa=0.37; 95% CI, 0.10 to 0.63). Adding FEES to VFSS significantly increased the detection rates of penetration, aspiration, and pharyngeal residue. No severe adverse events were noted during FEES, except for two cases of epistaxis, which stopped spontaneously without requiring any packing. CONCLUSIONS: This study demonstrated that the addition of endoscopist-directed FEES to VFSS increased the detection rates of penetration, aspiration, and pharyngeal residue.
Aged ; Deglutition/*physiology ; Deglutition Disorders/*diagnosis/radiography ; Female ; Fluoroscopy/methods ; Humans ; Laryngoscopy/*methods/statistics & numerical data ; Male ; Middle Aged ; *Pharynx/radiography ; Reproducibility of Results ; Retrospective Studies ; Video Recording

This study is to identify the characteristics of BMD and the related clinical consequences through a nationwide, consecutive, cross-sectional study. A total of 1,281 postmenopausal women was enrolled nationwide and underwent measurement for BMD using dual energy x-ray absorptiometry. Following the T-spine and L-spine plane radiography, they were evaluated for vertebral fracture by a semi-quantitative method using the Genant's method. Relationship between BMD and osteoporotic fracture and a degree of deformity in vertebral fracture, treatment history in osteoporosis and the EQ-5D was analyzed. The distribution of the normal, osteopenia and osteoporosis group was 25.9%, 37.0%, and 37.2% in lumbar spine, and 31.4%, 45.3%, and 23.3% in femur neck, respectively. BMD in subjects with symptomatic or asymptomatic vertebral fracture was significantly lower than those without fracture. The femur neck and total hip BMDs were significantly lower in hip fracture group (0.646 g/cm2 and 0.643 g/cm2, respectively) and wrist fracture group (0.661 g/cm2 and 0.712 g/cm2, respectively) than in subjects without fracture (0.721 g/cm2 and 0.712 g/cm2, respectively). The BMD was significantly lower with more severe degree of deformity in vertebral fracture and lower scores in mobility, usual activities and pain/discomfort of the EQ-5D. In Korean postmenopausal women, the prevalence of osteoporosis and vertebral, hip and wrist fracture increase and quality of life decreases with lower BMD.
Aged ; Aged, 80 and over ; *Bone Density ; Comorbidity ; Cross-Sectional Studies ; Female ; Humans ; Incidence ; Middle Aged ; Osteoporosis, Postmenopausal/*epidemiology/*radiography ; Osteoporotic Fractures/*epidemiology/*radiography ; Postmenopause ; Reproducibility of Results ; Republic of Korea/epidemiology ; Risk Assessment ; Sensitivity and Specificity ; Statistics as Topic ; Women's Health/statistics & numerical data

This study is to identify the characteristics of BMD and the related clinical consequences through a nationwide, consecutive, cross-sectional study. A total of 1,281 postmenopausal women was enrolled nationwide and underwent measurement for BMD using dual energy x-ray absorptiometry. Following the T-spine and L-spine plane radiography, they were evaluated for vertebral fracture by a semi-quantitative method using the Genant's method. Relationship between BMD and osteoporotic fracture and a degree of deformity in vertebral fracture, treatment history in osteoporosis and the EQ-5D was analyzed. The distribution of the normal, osteopenia and osteoporosis group was 25.9%, 37.0%, and 37.2% in lumbar spine, and 31.4%, 45.3%, and 23.3% in femur neck, respectively. BMD in subjects with symptomatic or asymptomatic vertebral fracture was significantly lower than those without fracture. The femur neck and total hip BMDs were significantly lower in hip fracture group (0.646 g/cm2 and 0.643 g/cm2, respectively) and wrist fracture group (0.661 g/cm2 and 0.712 g/cm2, respectively) than in subjects without fracture (0.721 g/cm2 and 0.712 g/cm2, respectively). The BMD was significantly lower with more severe degree of deformity in vertebral fracture and lower scores in mobility, usual activities and pain/discomfort of the EQ-5D. In Korean postmenopausal women, the prevalence of osteoporosis and vertebral, hip and wrist fracture increase and quality of life decreases with lower BMD.
Aged ; Aged, 80 and over ; *Bone Density ; Comorbidity ; Cross-Sectional Studies ; Female ; Humans ; Incidence ; Middle Aged ; Osteoporosis, Postmenopausal/*epidemiology/*radiography ; Osteoporotic Fractures/*epidemiology/*radiography ; Postmenopause ; Reproducibility of Results ; Republic of Korea/epidemiology ; Risk Assessment ; Sensitivity and Specificity ; Statistics as Topic ; Women's Health/statistics & numerical data

OBJECTIVE: To determine in vivo efficacy of radiofrequency ablation (RFA) in porcine liver by using 15-gauge Octopus(R) (15-G Octopus(R)) electrodes to create a large coagulation. MATERIALS AND METHODS: A total of 18 coagulations were created by using a 180-W generator and 15-G Octopus(R) electrodes during laparotomy, performed in 14 pigs. Coagulation necrosis was created in the pig livers by the use of one of three RFA protocols: 1) group A, monopolar RFA using a 15-G Octopus(R) electrode with a 5-mm inter-electrode distance (n = 4); 2) group B, monopolar RFA using a 15-G Octopus(R) electrode with a 10-mm inter-electrode distance (n = 6); and 3) group C, switching monopolar RFA using two 15-G Octopus(R) electrodes (n = 8). The energy efficiency, shape, maximum and minimum diameters (Dmx and Dmi), and the volume of the coagulation volume were measured in each group. The Summary statistics were obtained and Mann-Whitney test was were performed. RESULTS: The mean ablated volume of each group was 49.23 cm3 in A, 64.11 cm3 in B, and 72.35 cm3 in C. The mean Dmx and Dmi values were 5.68 cm and 4.58 cm in A and 5.97 cm and 4.97 cm in B, respectively. In group C, the mean diameters of Dmx and Dmi were 6.80 cm and 5.11 cm, respectively. The mean ratios of Dmi/Dmx were 1.25, 1.20, and 1.35 in groups A, B, and C, respectively. There was one animal death during the RFA procedure, the cause of which could not be subsequently determined. However, there were no other significant, procedure-related complications during the seven-hour-delayed CT scans. CONCLUSION: RFA procedures using 15-G Octopus(R) electrodes are useful and safe for creating a large ablation in a single electrode model as well as in the multiple electrodes model.
Animals ; Catheter Ablation/*methods ; Electrocoagulation/*instrumentation ; *Electrodes ; Liver/radiography/*surgery ; Statistics, Nonparametric ; Swine ; Tomography, X-Ray Computed

This study was performed to develop and evaluate a semi-automatic seed localization algorithm from magnetic resonance (MR) images for interstitial prostate brachytherapy. The computerized tomography (CT) and MR images (3 mm-slice thickness) of six patients who had received real-time MR imaging-guided interstitial prostate brachytherapy were obtained. An automatic seed localization method was performed on CT images to obtain seed coordinates, and an algorithm for seed localization from MR images of the prostate was developed and tested. The resultant seed distributions from MR images were then compared to CT-derived distribution by matching the same seeds and calculating percent volume receiving 100% of the prescribed dose and the extent of the volume in 3-dimensions. The semiautomatic seed localization method made it possible to extract more than 90% of the seeds with either less than 8% of noises or 3% of missing seeds. The mean volume difference obtained from CT and MR receiving 100% of the prescribed dose was less than 3%. The maximum extent of the volume receiving the prescribed dose were 0.3, 0.6, and 0.2 cm in x, y, and z directions, respectively. These results indicate that the algorithm is very useful in identifying seeds from MR image for post-implant dosimety.
Algorithms ; Brachytherapy/*methods/statistics & numerical data ; Humans ; Iodine Radioisotopes/*administration & dosage ; *Magnetic Resonance Imaging, Interventional/statistics & numerical data ; Male ; Prostatic Neoplasms/*pathology/radiography/*radiotherapy ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; Tomography, X-Ray Computed/statistics & numerical data ; Tumor Burden