A novel protocol for abdominal low-dose CT scans adapted with a model-based iterative reconstruction method.

PURPOSE: This study aims to introduce a novel low-dose abdominal computed tomography (CT) protocol adapted with model-based iterative reconstruction (MBIR), To validate the adaptability of this protocol, objective image quality and subjective clinical scores of low-dose MBIR images are compared with the normal-dose images. METHODS: Normal-dose abdominal CT images of 58 patients and low-dose abdominal CT images of 52 patients are reconstructed using both conventional filtered back projection (FBP) and MBIR methods with and without smooth applying. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) are used to compare image quality between the normal-dose and low-dose CT scans. CT dose indices (CTDI) of normal-dose and low-dose abdominal CT images on post-contrast venous phase are also compared. RESULTS: The SNR, CNR and clinical score of low-dose MBIR images all show significant higher values (Bonferroni p < 0.05) than those of normal-dose images with conventional FBP method. A total of around 40% radiation dose reduction (CTDI: 5.3 vs 8.7 mGy) could be achieved via our novel abdominal CT protocol. CONCLUSIONS: With the higher SNR/CNR and clinical scores, the low-dose CT abdominal imaging protocol with MBIR could effectively reduce the radiation for patients and provide equal or even higher image quality and also its adaptability in clinical abdominal CT image diagnosis.

Development of an Automated Bone Mineral Density Software Application: Facilitation Radiologic Reporting and Improvement of Accuracy.

The conventional method of bone mineral density (BMD) report production by dictation and transcription is time consuming and prone to error. We developed an automated BMD reporting system based on the raw data from a dual energy X-ray absorptiometry (DXA) scanner for facilitating the report generation. The automated BMD reporting system, a web application, digests the DXA's raw data and automatically generates preliminary reports. In Jan. 2014, 500 examinations were randomized into an automatic group (AG) and a manual group (MG), and the speed of report generation was compared. For evaluation of the accuracy and analysis of errors, 5120 examinations during Jan. 2013 and Dec. 2013 were enrolled retrospectively, and the context of automatically generated reports (AR) was compared with the formal manual reports (MR). The average time spent for report generation in AG and in MG was 264 and 1452 s, respectively (p < 0.001). The accuracy of calculation of T and Z scores in AR is 100 %. The overall accuracy of AR and MR is 98.8 and 93.7 %, respectively (p < 0.001). The mis-categorization rate in AR and MR is 0.039 and 0.273 %, respectively (p = 0.0013). Errors occurred in AR and can be grouped into key-in errors by technicians and need for additional judgements. We constructed an efficient and reliable automated BMD reporting system. It facilitates current clinical service and potentially prevents human errors from technicians, transcriptionists, and radiologists.

Effect of electrical discharging on formation of nanoporous biocompatible layer on Ti-6Al-4V alloys.

PURPOSE: In this study, the electrical discharge machining (EDM) was formed on the surface of the Ti-6Al-4V (Ti64) specimen. MATERIALS: The properties of adhesion and proliferation of MG-63 cells were evaluated the interactions between the EDM-treated layer and cells. RESULTS: The incorporation of oxygen roughened the EDM-treated specimen surface on a microscale, where the nanoscale pores were superimposed. The EDM-treated layer, which can generate the thick anatase TiO2 on the Ti64 surface, afforded a cytocompatible environment. In cell culture, alkaline phosphatase activity and osteocalcin can be dramatically enhanced on the EDM-treated surfaces when compared with the untreated surface. In addition, the increase in peak currents to the EDM functionalization led to enhancement of multiple osteoblast functions. CONCLUSIONS: This study reveals that the chemistry and crystallinity of the EDM-treated layer played important roles in affecting osteoblastic responses to the specimens, which provided insight into the development of new biomedical implant surfaces.

Contrast-enhanced ultrasound-guided biopsy of suspicious breast lesions on contrast-enhanced mammography and contrast-enhanced MRI: a case series.

PURPOSE: To assess the effectiveness of contrast-enhanced ultrasound (CEUS) in guiding biopsies of breast lesions that were detected on contrast-enhanced mammography (CEM) or contrast-enhanced breast MRI (CE-MRI) but were not clearly visible on B-mode ultrasound (B-US). METHODS: In this study, 23 lesions in 16 patients were selected for CEUS-guided biopsy due to poor visualization on B-US despite being detected on CEM (n = 20) or CE-MRI (n = 3). B-US, color Doppler ultrasound (CDUS), and CEUS were used to visualize the suspicious lesions, followed by a CEUS-guided core needle biopsy using Sonazoid as the contrast agent. The accuracy of the biopsy was assessed based on pathology-radiology concordance and 12-month imaging follow-up. The conspicuity scores for lesion visualization were evaluated using a 5-point conspicuity scale agreed upon by two breast radiologists. RESULTS: The enhancing lesions detected on CEM/CE-MRI had an average size of 1.6 ± 1.3 cm and appeared as mass-enhancing (61%) or non-mass-enhancing (39%). The lesions had mean conspicuity scores of 2.30 on B-US, 2.78 on CDUS, and 4.61 on CEUS, with 96% of the lesions showing contrast enhancement on CEUS. CEUS-guided biopsy showed increased visibility in 96% and 91% of the lesions compared to B-US and CDUS, respectively. The overall accuracy of CEUS-guided biopsy was 100% based on concordance with histology and 12-month follow-up. CONCLUSIONS: CEUS enhances the visibility of suspicious CEM/CE-MRI lesions that are poorly visible on B-US during biopsy procedures.

Aberrant femoral torsion presenting with frog-leg squatting mimicking gluteal muscle contracture.

BACKGROUND: Patients with frog-leg squatting have restricted internal rotation and adduction of the affected hips during sitting or squatting. In the surgical literature, the cause generally has been presumed to arise from and be pathognomonic for gluteal muscle contracture. However, we have encountered patients with frog-leg squatting but without gluteal muscle contracture. QUESTIONS/PURPOSES: We therefore raised the following questions: What are the imaging features of patients with frog-leg squatting? Do conditions other than gluteal muscle contracture manifest frog-leg squatting? PATIENTS AND METHODS: We retrospectively reviewed the MR images of 67 patients presenting with frog-leg squatting from April 1998 to July 2010. There were four females and 63 males; their mean age was 22.2 years (range, 4-50 years). During MRI readout, we observed aberrant axes of some femoral necks and obtained additional CT to measure femoral torsion angles in 59 of the 67 patients. RESULTS: MR images of 27 (40%) patients had signs of gluteal muscle contracture. Twenty-two (33%) patients (40 femora) had aberrant femoral torsion, including diminished anteversion (range, 6°-0°; average, 3.9°) in 11 femora of eight patients and femoral retroversion (range, < 0° to -31°, average, -7.5°) in 29 femora of 17 patients. The remaining 18 (27%) patients did not have gluteal muscle contracture or aberrant femoral torsion. The observation of aberrant femoral torsion was not anticipated before imaging studies. CONCLUSIONS: In addition to gluteal muscle contracture, aberrant femoral torsion can be a cause of frog-leg squatting. LEVEL OF EVIDENCE: Level II, diagnostic study. See the guidelines for Authors for a complete description of levels of evidence.

Focal bone abnormality as a complication of ultrasound diathermy: a report of eight cases.

PURPOSE: To review the magnetic resonance (MR) imaging findings in eight patients who developed marrow lesions after undergoing physiotherapy with use of ultrasound diathermy. MATERIALS AND METHODS: The authors retrospectively reviewed the medical charts and MR images of eight patients (six women and two men aged 22-69 years) who received ultrasound diathermy treatment for a variety of soft tissue injuries involving primarily the knee, shoulder, and wrist. All patients underwent MR imaging without the use of intravenous gadolinium-based contrast material. The institutional review board approved the study, and the requirement to obtain informed consent was waived. RESULTS: MR imaging of all patients revealed subcortical rim or arc lesions with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images, without involvement of the deeper aspect of the bone marrow. The imaging features of the lesions were similar to those of focal osteonecrosis. Follow-up MR imaging performed in three patients approximately 2-3 months after cessation of ultrasound therapy revealed resolution of the bone lesions. Symptoms resolved in all patients. CONCLUSION: This study demonstrated that ultrasound diathermy may produce an osseous injury. The abnormality itself was usually mild and transient, with apparent full recovery after termination of therapy.

Kinetic patterns of benign and malignant breast lesions on contrast enhanced digital mammogram.

PURPOSE: To evaluate the kinetic patterns of benign and malignant breast lesions using contrast-enhanced digital mammogram (CEDM). METHODS: Women with suspicious breast lesions on mammography or ultrasound were enrolled. Single-view mediolateral oblique (MLO) CEDM of an affected breast was acquired at 2, 3, 4, 7, and 10 min after injection of contrast agent. Three readers visually and semi-quantitatively analyzed the enhancement of suspicious lesions. The kinetic pattern of each lesion was classified as persistent, plateau, or washout over two time intervals, 2-4 min and 2-10 min, by comparing the signal intensity at the first time interval with that at the second. RESULTS: There were 73 malignant and 75 benign lesions in 148 patients (mean age: 52 years). Benign and malignant breast lesions showed the highest signal intensity at 3 min and 2 min, respectively. Average areas under receiver operating characteristic (ROC) curve for diagnostic accuracy based on lesion enhancement at different time points were 0.73 at 2 min, 0.72 at 3 min, 0.69 at 4 min, 0.67 at 7 min, and 0.64 at 10 min. Diagnostic performance was significantly better at 2, 3, and 4 min than at 7 and 10 min (all p < 0.05). A washout kinetic pattern was significantly associated with malignant lesions at 2-4 min and 2-10 min frames according to two of the three readers' interpretations (all p ≤ 0.001). CONCLUSION: Applications of optimal time intervals and kinetic patterns show promise in differentiation of benign and malignant breast lesions on CEDM.

Unsupervised Learning and Pattern Recognition of Biological Data Structures with Density Functional Theory and Machine Learning.

By introducing the methods of machine learning into the density functional theory, we made a detour for the construction of the most probable density function, which can be estimated by learning relevant features from the system of interest. Using the properties of universal functional, the vital core of density functional theory, the most probable cluster numbers and the corresponding cluster boundaries in a studying system can be simultaneously and automatically determined and the plausibility is erected on the Hohenberg-Kohn theorems. For the method validation and pragmatic applications, interdisciplinary problems from physical to biological systems were enumerated. The amalgamation of uncharged atomic clusters validated the unsupervised searching process of the cluster numbers and the corresponding cluster boundaries were exhibited likewise. High accurate clustering results of the Fisher's iris dataset showed the feasibility and the flexibility of the proposed scheme. Brain tumor detections from low-dimensional magnetic resonance imaging datasets and segmentations of high-dimensional neural network imageries in the Brainbow system were also used to inspect the method practicality. The experimental results exhibit the successful connection between the physical theory and the machine learning methods and will benefit the clinical diagnoses.

Co-firing of paper mill sludge and coal in an industrial circulating fluidized bed boiler.

Co-firing of coal and paper mill sludge was conducted in a 103 MWth circulating fluidized bed boiler to investigate the effect of the sludge feeding rate on emissions of SOx, NOx, and CO. The preliminary results show that emissions of SOx and Nx decrease with increasing sludge feeding rate, but CO shows the reverse tendency due to the decrease in combustion temperature caused by a large amount of moisture in the sludge. All emissions met the local environmental requirements. The combustion ashes could be recycled as feed materials in the cement manufacturing process.

Gadoxetic acid-enhanced MRI and sonoelastography: non-invasive assessments of chemoprevention of liver fibrosis in thioacetamide-induced rats with Sho-Saiko-To.

BACKGROUND: This study aimed to compare the performance of gadoxetic acid -enhanced magnetic resonance imaging (MRI) and sonoelastography in evaluating chemopreventive effects of Sho-Saiko-To (SST) in thioacetamide (TAA)-induced early liver fibrosis in rats. MATERIALS AND METHODS: Ten of Sprague-Dawley rats receiving TAA (200 mg/kg of body weight) intraperitoneal injection were divided into three groups: Group 1 (TAA only, n = 3), Group 2 (TAA +0.25 g/kg SST, n = 4) and Group 3 (TAA+1 g/kg SST, n = 3). Core needle liver biopsy at week 2 and liver specimens after sacrifice at week 6 confirmed liver fibrosis using histological examinations, including Sirius red staining, Ishak and Metavir scoring systems. Gadoxetic acid-enhanced MRI and shear-wave sonoelastography were employed to evaluate liver fibrosis. The expression of hepatic transporter organic anion transporter 1 (Oatp1), multidrug-resistant protein 2 (Mrp2) and alpha-smooth muscle actin (α-Sma) were also analyzed in each group by immunohistochemistry (IHC) and Western blot. RESULTS: According to histological grading by Sirius red staining, Ishak scores of liver fibrosis in Groups 1, 2 and 3 were 3, 2 and 1, respectively. As shown in gadoxetic acid-enhanced MRI, the ratio of relative enhancement was significantly lower in Group 1 (1.87 ± 0.21) than in Group 2 of low-dose (2.82 ± 0.25) and Group 3 of high-dose (2.72 ± 0.12) SST treatment at 10 minutes after gadoxetic acid intravenous injection (p < 0.05). Sonoelastography showed that the mean difference before and after experiments in Groups 1, 2 and 3 were 4.66 ± 0.1, 4.4 ± 0.57 and 3 ± 0.4 KPa (p < 0.1), respectively. Chemopreventive effects of SST reduced the Mrp2 protein level (p < 0.01) but not Oatp1 and α-Sma levels. CONCLUSION: Sonoelastography and gadoxetic acid-enhanced MRI could monitor the treatment effect of SST in an animal model of early hepatic fibrosis.

Imaging features of posterior limbus vertebrae.

Posterior limbus vertebra (PLV) is the retropulsion of the vertebral ring apophysis resulting from disc herniation through posterior ring physis. Large PLV can cause spinal stenosis, and small PLV can be mistaken as intraspinal disc herniation. Although the clinical presentations were similar, the surgery was quite different. We had experienced preoperative misdiagnosed cases and the surgery could not be finished. Therefore we analyzed the imaging features of PLV in 34 patients in order to prompt appropriate preoperative diagnosis and surgical planning.

MRI diagnosis of fibrolipomatous hamartoma of the median nerve and associated macrodystrophia lipomatosa.

Fibrolipomatous hamartoma is an uncommon congenital disorder, which is characterized by disproportionate hyperplasia of adipose tissue infiltrating along the perineurium, the epineurium and the affected nerve trajectory. We present a case of combined fibrolipomatous hamartoma and macrodystrophia lipomatosa of the median nerve. The involved sites included the left palm, wrist and forearm. Part of the patient's middle finger had been amputated due to previous macrodystrophia lipomatosa; however, the lesion continued to enlarge and was accompanied by numbness. Magnetic resonance imaging demonstrated a typical fibrolipomatous hamartoma with high signal intensity of fat on both T1-weighted and T2-weighted images, characteristic coaxial cable appearance on axial images, and spaghetti appearance on sagittal images. A similar skipped lesion at the median nerve of the middle forearm was also noted. To the best of our knowledge, this has not been reported in the English literature.