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CT density of cervical thymus, in comparison with mediastinal thymus

CT density of cervical thymus, in comparison with mediastinal thymus

Although the thymus is predominantly a mediastinal organ, part of it can often be seen in lower neck normally [1, 2]. When seen in the lower neck, cervical thymus has to be differentiated from pathologies like cervical lymph node, thyroid/parathyroid mass, or anatomic variants like enlarged distal thoracic duct [3]. In children, branchial cleft anomaly, teratoma, venous malformation, and lipoma also need to be excluded [4]. CT texture (lobules of soft tissue interspersed with fat) [1], similarity with CT density of mediastinal thymus [5] and continuity with mediastinal thymus on sagittal/coronal images, are given as the criteria
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CT Density Measurement and H:H Ratio Are Useful in Diagnosing Acute Cerebral Venous Sinus Thrombosis

CT Density Measurement and H:H Ratio Are Useful in Diagnosing Acute Cerebral Venous Sinus Thrombosis

Records of the remaining 20 patients (17 women, 3 men; mean age, 35.1 years; age range, 0 – 60 years) with confirmed acute CVST were analyzed. Patient demographics, hemoglobin, HCT, serum urea nitrogen, and creatinine levels from the day of the examination or 1 day before or after were documented. The loca- tion of the thrombus is listed in the Table. All CT images were acquired on 1 of 3 different systems: Sensation 64, Sensation 16, or Navigator (Siemens, Erlangen, Germany). The following scan- ning parameters were used: 120 kV, 300 mA, and a section thick- ness of 2.5 below the tentorium and 6 mm above the tentorium.
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The correlation of intramuscular fat content between muscles of the lamb carcass and the use of computed tomography to predict intramuscular fat percentage in lambs

The correlation of intramuscular fat content between muscles of the lamb carcass and the use of computed tomography to predict intramuscular fat percentage in lambs

The precision of IMF% prediction in lamb was markedly improved if the muscle is known and used in the prediction model. This indicates there are factors more in fl uential than IMF% that elicit differences in density between muscles. This is further evidenced by the poor association of IMF% and average CT pixel density between muscles, an example being the m. longissimus lumborum which despite having the highest average CT pixel density did not have the lowest IMF%. The reason for these discrepancies is likely attributed to the fact that muscles like the m. longissimus lumborum appear to be quite homogenous on a CT image, with the majority of the pixels classi fi ed as being muscle, with fi bres predominantly running parallel to each other. In con- trast the m. supraspinatus , m. infraspinatus and m. semi- membranosus have more multidirectional fi bres when examined on cut surface. This is related to differences in structure and function, which may in fl uence how they appear as a CT image. The amount of elastin in the m. semi- tendinosus for example, may in fl uence the average CT pixel density of the muscle and therefore interfere with the pre- diction of IMF between muscles. Additionally the size and shape of the intramuscular fat within muscles may impact on the calculated CT density of the muscle. Furthermore, postmortem changes to muscles may impact the CT density of the muscle, with this impact potentially varying between muscle locations.
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Dense breast stromal tissue shows greatly increased concentration of breast epithelium but no increase in its proliferative activity

Dense breast stromal tissue shows greatly increased concentration of breast epithelium but no increase in its proliferative activity

numbers of epithelial cells in TDLUs and ducts and the num- bers that were MIB1 positive, were counted with the help of an automated microscope system that digitized the images and permitted the outlining of relevant areas on a high-resolution computer screen (ACIS II; Clarient, Inc., San Juan Capistrano, CA, USA). The total numbers of epithelial cells in different out- lined areas within the CT density-defined areas was then auto- matically counted by the ACIS II nuclear counting software program, which is based on color identification. Hematoxylin was used to counterstain the MIB1-negative nuclei blue, and the DAB chromogen marked the MIB1-positive nuclei brown. Table 1
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Clinical impact of high-attenuation and cystic areas on computed tomography in fibrotic idiopathic interstitial pneumonias

Clinical impact of high-attenuation and cystic areas on computed tomography in fibrotic idiopathic interstitial pneumonias

of each region can reflect the differences among the re- gions, the features of different ROIs offset each other in the histogram analysis of the whole lung, leading to conflicting results of comparisons between different pathological pat- terns [3, 20]. Indeed, our results showed no significant dif- ferences in densitometric parameters between the IPF and non-IPF groups. Given the significant association between densitometric parameters and physiological impairments and long-term outcomes, the densitometric parameters of the whole lung might represent the physiological burdens of disease rather than pathological patterns. The novel CT indices used in this study, %HAA and %CA, are presumed to reflect the fibrotic and honeycombing lesions, respect- ively. The %HAA was similar between the IPF and non-IPF groups. Although a different definition was used, the per- centages of low, intermediate, and high CT density areas did not differ between UIP and NSIP in a previous study [20]. Similar to the densitometric parameters, the %HAA or high-density area might not be an index for morpho- logical characteristics but might instead be an index for the extent and severity of disease. Of note, the %CA was higher in patients with IPF and correlated with the extent of hon- eycombing by visual scoring in our study. Those results suggest the possibility that the %CA can detect the patho- logical features of IPF/UIP even in whole-lung analyses.
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Dysembryoplastic neuroepithelial tumors: MR and CT evaluation

Dysembryoplastic neuroepithelial tumors: MR and CT evaluation

PURPOSE: To evaluate dysembryoplastic neuroepithelial tumors (DNTs) on MR and CT studies and to compare DNT with other frequently encountered epileptogenic glioneuronal lesions. METH- ODS: We analyzed the MR images and CT scans of 16 patients who had complex partial epilepsy and DNT with respect to tumor location, size, CT density, MR signal intensity, mass effect, contrast enhancement, and heterogeneity, and compared these features with CT and MR findings in 51 cases of ganglioglioma and 33 cases of glioneuronal malformation. RESULTS: DNTs were located in the temporal lobe in 14 patients and in the frontal lobe in 2 patients. The cortex was involved in all cases and the subcortical white matter in 10 cases. Fifty percent of the tumors had poorly defined contours. On MR images, 14 DNTs had multiple cysts and 2 had single cysts. Contrast enhancement was observed in 6 DNTs, and mass effect was present in 9. CT scans disclosed moderately hypodense lesions in 7 patients and markedly hypodense cystic lesions in 6 patients. Two DNTs were calcified. Tumor hemorrhage with perifocal edema was observed in 1 case. Contrary to previous reports, slow but definite tumor growth was present during a 13-year period in 2 of 6 patients in whom serial CT or MR studies were obtained. CONCLUSION: A multicystic appearance on MR images is a characteristic feature of DNT and corresponds to its myxoid matrix and multinodular architecture. This feature is rare in gangliogliomas and glioneuronal malforma- tions, and, as such, may help differentiate DNTs from these disorders.
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Case Report Supratentorial atypical ectopic ependymoma in a child: a case report

Case Report Supratentorial atypical ectopic ependymoma in a child: a case report

nent, commonly with cystic areas and coarse calcifications in supratentorial lesions [12]. It was difficult to diagnosis for which had atypia maging findings, slightly low density mass with- out cystic components and calcification. MRI evaluations should include brain and spine imaging with and without contrast. Epen- dymomas are generally iso- to hypointense on T1-WI and iso- to hyperintense on T2-WI and fluid-attenuate diversion recovery. With admin- istration of gadolinium, the majority of ependy- momas exhibit a heterogeneous enhancement [13, 14]. Supratentorial atypical ectopic epen- dymoma usually have the cystic areas and coarse calcifications on MRI images. On MRI, masses can be solid or have a “cyst and mural nodule” formation, resulting in a differential diagnosis of pilocytic astrocytoma, ganglio- glioma, and pleomorphic xanthoastrocytoma. Comparison with MRI findings, the child had
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Density of the midpalatal suture after RME treatment – a retrospective comparative low-dose CT-study

Density of the midpalatal suture after RME treatment – a retrospective comparative low-dose CT-study

Low-dose CT scans were taken initially before placement of the RME (T0), directly after maximal activation (T1) and (in six cases) also in retention after 6 months (T2). Using a 3D-software ( “ OnDemand3D ” /Cybermed Inc.) in analogy to the method published by Franchi et al. (AJODO Volume 137/ Number 4) all values were measured twice at an interval of 1 month to assess the method error and the intraoperator reliability.

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Asynchrony in respiratory movements between the pulmonary lobes in patients with COPD: continuous measurement of lung density by 4-dimensional dynamic-ventilation CT

Asynchrony in respiratory movements between the pulmonary lobes in patients with COPD: continuous measurement of lung density by 4-dimensional dynamic-ventilation CT

This study has several limitations which should be noted. First, the total number of enrolled subjects was small, particu- larly the number of COPD patients. The very small number of female COPD patients (n = 2) may raise the question of whether our observations are applicable to all COPD patients. Also, many enrolled patients underwent the dynamic CT scan as a preoperative assessment for tumor invasion or adhesion to the pleura. Although we confirmed that no patient had a large tumor which invaded the adjacent structures or occluded the proximal bronchi, our observations should be reproduced among smokers/COPD patients without thoracic neoplasms in the future. Second, the dynamic-ventilation CT could not scan the entire thorax. Although we believed that it was best at the moment to utilize the MLD measurement instead of right and left LV measurements, true respiratory changes in LV
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Ab Initio calculation of parameters for electron and spin transport in organic crystals

Ab Initio calculation of parameters for electron and spin transport in organic crystals

is true regardless of whether the orbitals are orthonormal or not. What is less known, but which has been identified in the past with some progress [133], is that additional Pulay terms must be considered in cases where the degree of orbital nonorthogonality affects the total-energy. This occurs, whenever the energy depends on a nonorthogonality- respecting multi-centre projection of the density or Kohn-Sham density-matrix. It also occurs when using orthonormalised orbitals built from an underlying non-orthogonal set, since an ionic movement will typically break the orthornormality and render the orthonormalisation futile. Here we show that if we use the tensorially correct method of treating the population as a contraction of the density operator over kets and duals localized in the subspace [133], then we can have a simple and exact expression for the force without any need of constructing orthogonal orbitals.
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Focal Increased Cortical Density in Immediate Postembolization CT Scans of Patients with Intracranial Aneurysms

Focal Increased Cortical Density in Immediate Postembolization CT Scans of Patients with Intracranial Aneurysms

To summarize, we report a transient finding of cortical hyper- attenuation seen after apparently uneventful endovascular treatment of intracranial aneurysms, most likely resulting from some degree of BBB disruption that resulted in accumu- lation of contrast medium. Significant relationship was found between the occurrence of this finding and the amount of contrast material used per kilogram body weight, the micro- catheter time, the number of balloon inflations, the total time period of balloon inflation, and an inverse relation with the time elapsed until the CT was performed. Relatively increased amounts of contrast material injected intra-arterially in a se- lective territory and transient changes in brain hemodynamics (ie, flow compromise with subsequent reperfusion during the endosaccular packing) may have resulted in BBB disruption. Although no symptoms occurred in association with the ob- served cortical hyperattenuation, we believe that it is impor- tant to recognize this condition because it can mimic SAH (Fig 6), which may cause unnecessary intimidation and delay in anticoagulant/antiaggregant treatment.
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Small nerve fibre quantification in the diagnosis of diabetic sensorimotor polyneuropathy: comparing corneal confocal microscopy with intraepidermal nerve fibre density

Small nerve fibre quantification in the diagnosis of diabetic sensorimotor polyneuropathy: comparing corneal confocal microscopy with intraepidermal nerve fibre density

15 Because IENFD represents a measure of the most distal nerve fibres which are affected in DSPN, a natural assumption is that it should have a better diagnostic ability than CCM. However, a comparison between IENFD and CCM features for the individual diagnosis of DSPN has not been reported to date. In this paper, we present a comparison of nerve fibre features, quantified either manually or automatically from CCM images (CNFL, CNFD, and CNBD) with IENFD measurement in identifying DSPN in individuals. We show that automated, and hence more rapid and reproducible, quantification of CCM features show a high degree of consistency with those measured manually, confirming previously reported results indicating that these measures are equivalent (Dabbah et al., 2011, Petropoulos et al., 2014, Dehghani et al., 2014). The exception is the manually measured nerve branch density (CNBD), which has been found previously (Petropoulos et al., 2013) to be unreliable, due to the subjective judgement required in identifying branches. The algorithmic definition of branches in the automated measurement results in greater consistency, though this is the least useful individual automated CCM measurement. While both CCM and IENFD seek to measure small fibres, IENFD showed a poorer discrimination between those with and without DSPN. Furthermore, CCM measurements show considerably less variability within the subject groups than IENFD measurements. Interestingly, very low IENFD values were observed, even in control subjects.
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Smokers with emphysema and small airway disease on computed tomography have lower bone density

Smokers with emphysema and small airway disease on computed tomography have lower bone density

Abstract: Osteoporosis is more common in patients with COPD and in smokers. The aim of this study was to assess whether measures of emphysema and airway disease on computed tomography (CT) were associated with lower bone density or vertebral fractures in smokers with and without COPD. For this purpose, we included participants from the NELSON lung cancer screening trial. Bone density was measured as Hounsfield Units in the first lumbar vertebra, and vertebral fractures were assessed semiquantitatively. The 15th percentile method (Perc15) was used to assess emphysema, and the airway lumen perimeter (Pi10) was used for airway wall thickness. Expiratory/inspiratory-ratio mean lung density (E/I-ratio MLD ) was used as a measure for air trapping and tracheal index to assess tracheal deformity. Linear regression models and logistic regression models were used to assess associations between CT biomarkers, bone density, and presence of fractures. Exactly 1,093 male participants were eligible for analysis. Lower Perc15 and higher E/I-ratio MLD were significantly associated with lower bone density (b=−1.27, P=0.02 and b=−0.37, P=0.02, respectively). Pi10 and tracheal index were not associated with bone density changes. CT-derived biomarkers were not associated with fracture prevalence. Bone density is lower with increasing extent of emphysema and small airway disease but is not associated with large airway disease and tracheal deformity. This may indicate the necessity to measure bone density early in smokers with emphysema and air trapping to prevent vertebral fractures.
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A Rare Case of Asymptomatic Mediastinal Thymolipoma-presenting as Opaque Hemithorax

A Rare Case of Asymptomatic Mediastinal Thymolipoma-presenting as Opaque Hemithorax

The differential diagnosis for fat containing mass lesion in the mediastinum include lipoma mediastinal lipomatosis,liposarcoma,teratoma, diaphragmatic hernias, extramedullary erythropoiesis, lipoid pneumonia, lipoblastoma and cardiac liposarcomas [15,16,17]. As mentioned above, thymolipomas are fat density lesions admixed with streaks of soft tissue. If the soft tissue show contrast enhancement the possibility of liposarcoma are to be considered.

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Small dense LDL particles - a predictor of coronary artery disease evaluated by invasive and CT-based techniques: a case-control study

Small dense LDL particles - a predictor of coronary artery disease evaluated by invasive and CT-based techniques: a case-control study

We performed a case-control study of 194 consecutive patients with low or intermediate risk of CAD, referred for elective CAG (invasive CAG) at Aalborg Hospital between June 2007 and December 2008. Causes of refer- ral were angina pectoris or angina equivalent symptoms. Based on information of previous history, current symp- toms, and risk factors patients were categorized clini- cally as having a high risk or a low to intermediate risk of CAD. We carried out a CT CAG as well as an inva- sive CAG in all patients. Based on this, we grouped the patients in two parallel analyses, i.e. CAD/no CAD on CAG and CAD/no CAD on CT CAG, thus allowing parallel comparisons of sdLDL as a risk factor for CAD measured by different, yet clinically relevant, diagnostic modalities. Patients underwent a CT CAG and later, but within the same week, an invasive CAG, unless they met any of the following exclusion criteria:
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Sinusoidal And Non – Sinusoidal Airy Functions, Non – Linear Optical Behavior In Rose Bengal With Its Selective Organic Charge Transfer Complexes

Sinusoidal And Non – Sinusoidal Airy Functions, Non – Linear Optical Behavior In Rose Bengal With Its Selective Organic Charge Transfer Complexes

Although there is overall half-power beta density below Eg the modulation leads to nonlinear optical property (Figure 3c). The oscillatory behavior markedly differs from those arising from complex band gap (Alexander 1977,A.T.Oza). Square-power beta density below 800 cm -1 arising from optical phonons is also fitted (Figure 3d). The spectrum of Rose Bengal-DDQ is also shown (Figure 4a). Here too, the oscillatory behavior is clearly revealed between 1700 cm -1 and 900 cm -1 . The absorption dips are intense but broad while the absorption peaks are intense but sharp. This characteristic can be described by generalization of even the Airy function as discussed above. Egb is a saddle point. Acoustic phonon induced the half-power beta density is modulated by the generalized Airy function. Above Eg, the forbidden direct transition is found following absorption function (Figure4b). Half-power beta density is fitted for the average points due to modulation by general Airy function (Figure4c). The spectrum of Rose Bengal-TCNQ shows similar profile of transmission (Figure 5a). Even within the oscillatory region, noise is observed between 1400 cm -1 and 1600 cm -1 . This may be related with enhancement of photoconductivity of TCNQ complex. The oscillations around half-power beta density horizontal line are very similar to RB-DDQ.
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PubMedCentral-PMC4747602.pdf

PubMedCentral-PMC4747602.pdf

CT scans were performed on a Discovery CT750HD (GE Healthcare, Wisconsin, USA) scan- ner. The helical scan range was determined by a scout scan, and included the entire abdomen from the diaphragms to the pubic symphysis. Following the scout scan, a conventional non- enhanced helical scan was obtained at 120 kVp. Patients were then injected with a total dose of 100-140mL (1.8 mL per kilogram of body weight) of nonionic iodinated contrast material (Iopamidol 370 mg/mL; Shanghai Bracco Sine Phamaceutical Co., Ltd., China) at a rate of 3.5 mL/s followed by 50 mL saline solution using a power injector. Contrast-enhanced CT scans were performed in the arterial phase and venous phase with spectral CT imaging. Bolus track- ing was utilized with the region of interest placed in the aorta, and image acquisition started 7 s after the signal attenuation reached the predefined threshold of 100 Hounsfield units (HU) for the arterial phase. A 45-second delay was utilized as the venous phase.
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Supercell convergence of charge transfer energies in pentacene molecular crystals from constrained DFT

Supercell convergence of charge transfer energies in pentacene molecular crystals from constrained DFT

Singlet fission (SF) is a multi-exciton generation process that could be harnessed to improve the efficiency of photovoltaic devices. Experimentally, systems derived from the pentacene molecule have been shown to exhibit ultrafast SF with high yields. Charge-transfer (CT) configurations are likely to play an important role as intermediates in the SF process in these systems. In molecular crystals, electrostatic screening effects and band formation can be significant in lowering the energy of CT states, enhancing their potential to effectively participate in SF. In order to simulate these, it desirable to adopt a computational approach which is acceptably accurate, relatively inexpensive, which and scales well to larger systems, thus enabling the study of screening effects. We propose a novel, electrostatically-corrected constrained Density Functional Theory (cDFT) approach as a low-cost solution to the calculation of CT energies in molecular crystals such as pentacene. Here we consider an implementation in the context of the ONETEP linear-scaling DFT code, but our electrostatic correction method is in principle applicable in combination with any constrained DFT implementation, also outside the linear-scaling framework. Our newly developed method allows us to estimate CT energies in the infinite crystal limit, and with these to validate the accuracy of the cluster approximation.
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CT Classification of Ureteral Calculi Parameters for Predicting Ureteroscopy Complications

CT Classification of Ureteral Calculi Parameters for Predicting Ureteroscopy Complications

Our data indicate an overall complication rate of 77.5 percent. The majority of complications were minor such as renal colic and hematuria which required no further treatment outside of the usual standard of care. Renal colic although being a more common complaint did not show any direct correlation to CT scan parameters. For this reason we can conclude that most patients undergoing ureteroscopy will likely have some de- gree of renal colic irrespective of stone size, location, density, or stone composition without predictive parameters to de- termine in which patients it will occur. Hematuria associated with ureteroscopy can occur in varying degrees; however, one is usually able to complete the procedure without significant visual impairment. Abdel-Razzak and Bagley reported that in approximately 2% of cases bleeding was so severe that vision was impaired to a degree that termination of the operation was necessary. 5 Such bleeding can be secondary to vascular injury of the crossing vessels at the ureteropelvic or ureterovesicular junction or an intrarenal artery at an infundibulum. [6] Stone density greater than 800 HF units, stone size greater than 8 mm, and operative time longer than 53 minutes were indepen- dent risk factors for hematuria in this study.
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Chromosome territory repositioning induced by PHA-activation of lymphocytes: A 2D and 3D appraisal

Chromosome territory repositioning induced by PHA-activation of lymphocytes: A 2D and 3D appraisal

stimuli initiate cellular growth, transcriptional activation or induce DNA damage in vitro. The most prominent ex- ample for the former comes from pig mesenchymal stem cells when adipogenic growth factors added in culture give rise to committed pre-adipocyte cells. Six genes involved in the adipogenesis pathway repositioned to a more interior location after 14 days of treatment, corre- lated with up-regulation. The GATA2 gene moved from a peripheral to an interior location (day 7 – up-regulation) and back to a peripheral location (day 14 – down- regulation) [32]. Recently, we reported reproducible events of CT repositioning in human lymphocytes follow- ing in-vitro exposure to genotoxic agents, hydrogen peroxide and UVB [20]. Differences were also reported in CT repositioning between the two genotoxic agents most likely represents differences in mobility and/or deconden- sation of CTs as a result of differences in the DNA damage induced, chromatin regions targeted and different repair mechanisms [20]. With regards to stimulating a different transcriptional profile a single study has provided evidence of CT repositioning in human lymphocytes following acti- vation of lymphocytes using phytohaemagglutinin (PHA). PHA is a plant mitogen that induces the proliferation of mammalian lymphocytes and creates a cascade of biochem- ical events that activates resting lymphocytes, which results in large scale decondensation of chromatin, increases in nuclear size and leads to a distinct transcriptional profile [34]. Branco et al. [34] investigated the positioning of 11 CTs in resting human lymphocytes (-PHA) and activated human lymphocytes (+PHA) from a single female subject [34]. The findings showed some intraorganization of CTs with chromosomes 1 and 3 moving more peripherally and chromosome 21 being more centrally located in activated cells [34]. The differences between the two states were at- tributed to the nuclear expansion as a result of lymphocyte activation by PHA, and to the different transcriptional pro- gram [34]. Another important finding was the observation that CT intermingling was lower in activated lymphocytes. This finding was proposed to be a potential protective mechanism to prevent chromosome translocations or risk from DNA damage due to the controlled cell death program that occurs during T lymphocyte activation [34].
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