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Cone beam computed tomography (CBCT) is now widely used in dentistry and growing areas of medical imaging. The presence of strong metal artifacts is however a major concern of using CBCT especially in dentistry due to the presence of highly attenuating dental restorations, fixed appliances, and implants. Virtual monoenergetic images (VMIs) synthesized from dual energy CT (DECT) datasets are known to reduce metal artifacts. Although several techniques exist for DECT imaging, they in general come with significantly increased equipment cost and not available in dental clinics. The objectives of this study were to investigate the feasibility of developing a low-cost dual energy CBCT (DE-CBCT) by retrofitting a regular CBCT scanner with a carbon nanotube (CNT) x-ray source with dual focal spots and corresponding low-energy (LE) and high-energy (HE) spectral filters. A testbed with a CNT field emission x-ray source (NuRay Technology, Chang Zhou, China), a flat panel detector (Teledyne, Waterloo, Canada), and a rotating object stage was used for this feasibility study. Two distinct polychromatic x-ray spectra with the mean photon energies of 66.7keV and 86.3keV were produced at a fixed 120kVp x-ray tube voltage by using Al+Au and Al+Sn foils as the respective LE and HE filters attached to the exist window of the x-ray source. The HE filter attenuated the x-ray photons more than the LE filter. The calculated post-object air kerma rate of the HE beam was 31.7% of the LE beam. An anthropomorphic head phantom (RANDO, Nuclear Associates, Hicksville, NY) with metal beads was imaged using the testbed and the images were reconstructed using an iterative volumetric CT reconstruction algorithm. The VMIs were synthesized using an image-domain basis materials decomposition method with energy ranging from 30 to 150keV. The results were compared to the reconstructed images from a single energy clinical dental CBCT scanner (CS9300, Carestream Dental, Atlanta, GA). A significant reduction of the metal artifacts was observed in the VMI images synthesized at high energies compared to those from the same object imaged by the clinical dental CBCT scanner. The ability of the CNT x-ray source to generate the output needed to compensate the reduction of photon flux due to attenuation from the spectral filters and to maintain the CT imaging time was evaluated. The results demonstrated the feasibility of DE-CBCT imaging using the proposed approach. Metal artifact reduction was achieved in VMIs synthesized. The x-ray output needed for the proposed DE-CBCT can be generated by a fixed-anode CNT x-ray source.

IntroductionPrevious research has indicated that only children (i.e., those living with no siblings) have higher odds of obesity during childhood and young adulthood, compared with those living with siblings. However, little is known about whether the developing difference in overweight/obesity is accompanied by a difference in mental health (i.e., internalizing symptoms of depression and anxiety).MethodsThe subjects for this prospective study were a randomly generated cohort of 1348 high-school students in Guangzhou, China. Participants completed assessments of anthropometric indices, lipid profiles, family-based factors, lifestyle, and internalization of symptoms (including those of depression and anxiety).ResultsCompared to their peers with siblings, only children (adjusted odds ratio [aOR] = 1.68, 95% confidence interval [CI] [1.06, 2.65]) had significantly higher risk for obesity. However, only children with overweight/obesity had lower OR for depression at follow-up (aOR = 0.19, 95% CI [0.34, 0.86]), compared to individuals who were overweight/obese with siblings. This relationship was not significant for non-overweight individuals. No significant relationship between the number of siblings and anxiety at follow-up was observed, regardless of body mass index (BMI).ConclusionsAlthough being an only child was significantly associated with overweight and obesity among adolescents in China, participants with history of overweight/obesity are less likely to experience symptoms of depression associated with being an only child.

Our results confirmed the more aggressive behavior of PSRCC compared to MBC. This tumor is frequently associated with more frequent lymphatic metastasis, higher Ki67 labeling index, more advanced stage disease as well as simultaneous vimentin upregulation and E-cadherin downregulation. Different management guidelines should be considered for the two types.

PurposeCarbon nanoparticles have a strong affinity for the lymphatic system. The purpose of this study was to evaluate the feasibility of sentinel lymph node biopsy using carbon nanoparticles in early breast cancer and to optimize the application procedure.MethodsFirstly, we performed a pilot study to demonstrate the optimized condition using carbon nanoparticles for sentinel lymph nodes (SLNs) detection by investigating 36 clinically node negative breast cancer patients. In subsequent prospective study, 83 patients with clinically node negative breast cancer were included to evaluate SLNs using carbon nanoparticles. Another 83 SLNs were detected by using blue dye. SLNs detection parameters were compared between the methods. All patients irrespective of the SLNs status underwent axillary lymph node dissection for verification of axillary node status after the SLN biopsy.ResultsIn pilot study, a 1 ml carbon nanoparticles suspension used 10-15min before surgery was associated with the best detection rate. In subsequent prospective study, with carbon nanoparticles, the identification rate, accuracy, false negative rate was 100%, 96.4%, 11.1%, respectively. The identification rate and accuracy were 88% and 95.5% with 15.8% of false negative rate using blue dye technique. The use of carbon nanoparticles suspension showed significantly superior results in identification rate (p = 0.001) and reduced false-negative results compared with blue dye technique.ConclusionOur study demonstrated feasibility and accuracy of using carbon nanoparticles for SLNs mapping in breast cancer patients. Carbon nanoparticles are useful in SLNs detection in institutions without access to radioisotope.

To evaluate the intra- and inter-observer variability of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) criteria for the evaluation of middle cerebral artery (MCA) stenosis using digital subtraction angiography (DSA).DSA images of 114 cases with 131 stenotic MCAs were retrospectively analyzed. Two radiologists and a researcher measured the degree of MCA stenosis independently using both NASCET and WASID methods. To determine intra-observer agreement, all the observers reevaluated the degree of MCA stenosis 4 weeks later. The linear relation and coefficient of variation (CV) between the measurements made by the two methods were assessed by correlation coefficient and multi-factor analysis of variance (ANOVA), respectively. Intra- and inter-observer variability of the two methods was evaluated by intraclass correlation coefficient (ICC), Spearman's R value, Pearson correlation coefficient and Bland-Altman plots.Despite the fact that the degree of MCA stenosis measured by NASCET was lower than measured using the WASID method, there was good linear correlation between the measurements made by the two methods (for the mean measurements of the 3 observers, NASCET% = 0.891 × WASID% - 1.89%; ICC, Spearman's R value and Pearson correlation were 0.874, 0.855, and 0.874, respectively). The CVs of both intra- and inter-observer measurements of MCA stenosis using WASID were significantly lower than that using NASCET confirmed by the multi-factor ANOVA results, which showed only the measurement methods of MCA stenosis had significant effects on the CVs both in intra- and inter-observer measurements (both P values < 0.001). Intra-observer measurements showed good or excellent agreement with respect to WASID and NASCET evaluation (ICC, 0.656 to 0.817 and 0.635 to 0.761, respectively). Good agreement for the WASID evaluation (ICC, 0.592 to 0.628) and for the NASCET evaluation (ICC, 0.529 to 0.568) was observed for inter-observer measurements. Bland-Altman plots demonstrated that the WASID method had better reproducibility and intra-observer agreement than NASCET method for evaluating MCA stenosis.Both NASCET and WASID methods have an acceptable level of agreement; however, the WASID method had better reproducibility for the evaluation of MCA stenosis, and thus the WASID method may serve as a standard for measuring the degree of MCA stenosis.

To evaluate the scan-rescan reproducibility of high-resolution magnetic resonance imaging (MRI) of middle cerebral artery (MCA) plaque, and calculate the number of subjects needed for future longitudinal clinical studies.Twenty two patients with MCA plaque were scanned twice by a T2-weighted fast-spin-echo sequence at 3T. Areas and volumes of MCA lumen, total vessel and plaque were quantified and compared between two repeated scans. Agreement and measurement error was quantified by intraclass correlation coefficient (ICC) and coefficient of variance (CV) as defined by standard deviation (SD) of pair wise difference / mean. Sample size needed to detect 5% to 20% changes in area/volume was calculated using 80% power and 5% significance level.There was no significant different between the area and volume measurements of two repeated scans (p>0.05) with good agreement (ICC range 0.97-0.98 for area and 0.99 for volume). Relatively small measurement errors were observed with CVs range 6.1%-11.8% for area quantification and 4.9%-8.0% for volume quantification. Volume measurements tended to have 19.7% to 32.2% smaller CVs compared with area measurements. Sample size calculation showed a group of 47 patients was sufficient to detect 5% to 10% changes in MCA area/volume.High resolution MRI is feasible for quantifying intracranial plaque area and volume in longitudinal clinical studies with low scan-rescan variability. Volume measurement tends to be more reproducible compared with area measurements.

We aim to demonstrate the application of free-breathing prospectively gated carbon nanotube (CNT) micro-CT by evaluating a myocardial infarction model with a delayed contrast enhancement technique. Evaluation of murine cardiac models using micro-CT imaging has historically been limited by extreme imaging requirements. Newly-developed CNT-based x-ray sources offer precise temporal resolution, allowing elimination of physiological motion through prospective gating. Using free-breathing, cardiac-gated CNT micro-CT, a myocardial infarction model can be studied non-invasively and with high resolution. Myocardial infarction was induced in eight male C57BL/6 mice aged 8-12 weeks. The ischemia reperfusion model was achieved by surgically occluding the LAD artery for 30 minutes followed by 24 hours of reperfusion. Tail vein catheters were placed for contrast administration. Iohexol 300 mgI/mL was administered followed by images obtained in diastole. Iodinated lipid blood pool contrast agent was then administered, followed with images at systole and diastole. Respiratory and cardiac signals were monitored externally and used to gate the scans of free-breathing subjects. Seven control animals were scanned using the same imaging protocol. After imaging, the heart was harvested, cut into 1mm slices and stained with TTC. Post-processing analysis was performed using ITK-Snap and MATLAB. All animals demonstrated obvious delayed contrast enhancement in the left ventricular wall following the Iohexol injection. The blood pool contrast agent revealed significant changes in cardiac function quantified by 3-D volume ejection fractions. All subjects demonstrated areas of myocardial infarct in the LAD distribution on both TTC staining and micro-CT imaging. The CNT micro-CT system aids straightforward, free-breathing, prospectively-gated 3-D murine cardiac imaging. Delayed contrast enhancement allows identification of infarcted myocardium after a myocardial ischemic event. We demonstrate the ability to consistently identify areas of myocardial infarct in mice and provide functional cardiac information using a delayed contrast enhancement technique.

Contrast enhanced MRA (CE-MRA) can help to overcome the limitations of other techniques to clearly display the details of cerebral aneurysms at 1.5-T MR system. We investigated the prevalence of unruptured cerebral aneurysms (UCAs) using three dimensional (3D) CE-MRA in a tertiary comprehensive hospital in China.The cases were prospectively recorded at our hospital between February 2009 and October 2010. 3D CE-MRA, interpreted by 2 observers blinded to the participants' information, was used to identify the location and size of UCAs and to estimate the overall, age-specific, and sex-specific prevalence.Of the 3993 patients (men: women = 2159:1834), 408 UCAs were found in 350 patients (men: women = 151:199). The prevalence was 8.8% overall (95% CI, 8.0-10.0%), with 7.0% for men (CI, 6.0-8.0%) and 10.9% for women (CI, 9.0-12.0%). The overall prevalence of UCAs was higher in women than in men (P

OBJECTIVE: To investigate microcirculatory differences between pathologic types of kidney tumor using 320-slice dynamic volume CT perfusion. METHODS: Perfusion imaging with 320-slice dynamic volume CT was prospectively performed in 85 patients with pathologically proven clear cell renal cell carcinoma (RCC) (n = 66), papillary RCC (n = 7), chromophobe RCC (n = 5), angiomyolipoma (AML) with minimal fat (n = 7), or RCC (n = 78). Equivalent blood volume (Equiv BV), permeability surface-area product (PS; clearance/unit volume = permeability), and blood flow (BF) of tumor and normal renal cortex were measured and analyzed. Effective radiation dose was calculated. RESULTS: There was a significant difference in all three parameters between tumor and normal renal cortex (P

Many functions of vacuole depend on the activity of vacuolar ATPase which is essential to maintain an acidic lumen and create the driving forces for massive fluxes of ions and metabolites through vacuolar membrane. In filamentous fungus Magnaportheoryzae, subcellular colocalization and quinacrine staining suggested that the V1V0 domains of V-ATPase were fully assembled and the vacuoles were kept acidic during infection-related developments. Targeted gene disruption of MoVMA11 gene, encoding the putative c' subunit of V-ATPase, impaired vacuolar acidification and mimicked the phenotypes of yeast V-ATPase mutants in the poor colony morphology, abolished asexual and sexual reproductions, selective carbon source utilization, and increased calcium and heavy metals sensitivities, however, not in the typical pH conditional lethality. Strikingly, aerial hyphae of the MoVMA11 null mutant intertwined with each other to form extremely thick filamentous structures. The results also implicated that MoVMA11 was involved in cell wall integrity and appressorium formation. Abundant non-melanized swollen structures and rare, small appressoria without penetration ability were produced at the hyphal tips of the ΔMovma11 mutant on onion epidermal cells. Finally, the MoVMA11 null mutant lost pathogenicity on both intact and wounded host leaves. Overall, our data indicated that MoVMA11, like other fungal VMA genes, is associated with numerous cellular functions and highlighted that V-ATPase is essential for infection-related morphogenesis and pathogenesis in M. oryzae.

Histopathology forms the gold standard for the diagnosis of breast cancer. Multiphoton microscopy (MPM) has been proposed to be a potentially powerful adjunct to current histopathological techniques. A label-free imaging based on two- photon excited fluorescence and second-harmonic generation is developed for differentiating normal breast tissues, benign, as well as breast cancer tissues. Human breast biopsies (including human normal breast tissues, benign as well as breast cancer tissues ) that are first imaged (fresh, unfixed, and unstained) with MPM and are then processed for routine H-E histopathology. Our results suggest that the MPM images, obtained from these unprocessed biopsies, can readily distinguish between benign lesions and breast cancers. In the tissues of breast cancers, MPM showed that the tumor cells displayed marked cellular and nuclear pleomorphism. The tumor cells, characterized by irregular size and shape, enlarged nuclei, and increased nuclear-cytoplasmic ratio, infiltrated into disrupted connective tissue, leading to the loss of second-harmonic generation signals. For breast cancer, MPM diagnosis was 100% correct because the tissues of breast cancers did not have second-harmonic generation signals in MPM imaging. On the contrary, in benign breast masses, second-harmonic generation signals could be seen easily in MPM imaging. These observations indicate that MPM could be an important potential tool to provide label-free noninvasive diagnostic impressions that can guide surgeon in biopsy and patient management.

Since changes in the basement membranes are the critical indicators for differentiating normal, precancerous, and cancerous colonic tissues, direct visualization of these warning signs is essential for the early diagnosis and treatment of colonic cancer. Here, we present that second harmonic generation (SHG) microscopy can probe the changes of basement membranes in different colonic cancer stages. Our results also show the capability of using the quantitative analyses of images for quantifying these changes in different cancer stages. These results suggest that SHG microscopy has the potential in label-freely imaging the changes of basement membranes for effectively distinguishing between normal, precancerous, and cancerous colonic tissues. To our knowledge, this is the first demonstration of the dynamics of basement membrane changes in different colonic cancer stages using entirely intrinsic source of contrast.