Hounsfield Unit (HU)

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Diagnosing Cerebral Venous Sinus Thrombosis on Unenhanced Computed Tomography -Measuring the Hounsfield Unit. Does it Add to the Confirmation of Diagnosis?

Diagnosing Cerebral Venous Sinus Thrombosis on Unenhanced Computed Tomography -Measuring the Hounsfield Unit. Does it Add to the Confirmation of Diagnosis?

Hyperattenuating signs on CT are non-specific. They are frequently seen when an acute thrombus is formed with in a blood vessel [12]. Some other conditions which increase hematocrit or sluggish flow can also give increase attenuation. The increase in attenuation is measured by increase in Hounsfield unit (HU) on CT. The increase in attenuation is caused by clot retraction reducing water and increasing the concentration of RBCs and haemoglobin [13]. This mechanism can result in increased attenuation of the thrombus to 60-90HU.

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Different Spectral Hounsfield Unit Curve and High Energy Virtual Monochromatic Image Characteristics of Squamous Cell Carcinoma Compared with Nonossified Thyroid Cartilage

Different Spectral Hounsfield Unit Curve and High Energy Virtual Monochromatic Image Characteristics of Squamous Cell Carcinoma Compared with Nonossified Thyroid Cartilage

On contrast-enhanced CT, NOTC has relatively high intrinsic attenuation without measurable blood supply or iodine, whereas HNSCC demonstrates increased attenuation secondary to increased iodine content after administration of IV contrast. Therefore, be- cause of their different compositions, we hypothesized that DECT virtual monochromatic images reconstructed at different energy lev- els may be useful in distinguishing tumor from nonossified thyroid cartilage, and in this investigation, we compared the spectral Hounsfield unit attenuation curve (SHUAC) characteristics of HN- SCC with those of NOTC. The objective of our study was to evaluate the differences in spectral attenuation and determine the optimal virtual monochromatic image reconstruction energy levels for dis- tinguishing tumor from NOTC. This study compared the enhancing part of tumor with normal nonossified thyroid cartilage. Any part of the tumor potentially invading the cartilage, when present, was ex- cluded from quantitative ROI analysis to avoid cross-contamination from areas where there could potentially be a mixture of cartilage and invading tumor.

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Grading of cerebral infarction using CT Hounsfield unit to report the Hounsfield unit in acute, Subacute and chronic stroke

Grading of cerebral infarction using CT Hounsfield unit to report the Hounsfield unit in acute, Subacute and chronic stroke

secondary to volume loss takes place. T.L. Tan et al. introduced a new technique that, histogram based colorization in the infarcted area in the CT image. In his study observed that the HU values of old and early cerebral infarct which is more prominent to current study. He observed that the tissues have similar attenuation with white matter and sometimes it’s made difficulty to diagnose brain infarct. According to his observations for early infarct the HU range is in between 10and 20 and for old infarct 0 to 10, these are very similar to current study results, that is for acute infarct >19.13, sub-acute infarct HU range in between 9.55 to 19.13 and for chronic infarct less than 9.55. But his study is focused on to make segmentation between infracted area and other tissues. This colorization method doesn’t segmenting classes of cerebral Infarcts, so still it’s a tough task to radiologist to make it out the type of infarcts (Tan et al., ?). B. In a study conducted by Srikanth et al. study based on contra-lateral symmetry to identify stroke affected slices in a given CT volume. The new classification system is presented by them which will automatically find out the, CT brain boundary and classification of brain diseases. The author observed the range value of gray scale levels for main brain structures and for stroke tissues got the HU range as 20 to 30 but didn’t defined which type of cerebral infarct it is . By his new automatic technique can found out only acute infarct, chronic infarct and hemorrhage, can’t differentiate type of infarct (Srikanth et al., 2012). A similar study was conducted by Mayank et al. to detect acute infarct, chronic infarct and hemorrhage at the slice level of non-contrast CT images. But he used a histogram method to do this in contrast to the present

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<p>Hounsfield Unit Values in ACR TI-RADS 4-5 Thyroid Nodules with Coarse Calcifications: An Important Imaging Feature Helpful for Diagnosis</p>

<p>Hounsfield Unit Values in ACR TI-RADS 4-5 Thyroid Nodules with Coarse Calcifications: An Important Imaging Feature Helpful for Diagnosis</p>

Patients and Methods: CT images of 216 ACR TI-RADS 4-5 nodules with coarse calci fi cations from 207 patients who underwent surgery in our hospital between 2017 and 2019 were retrospectively reviewed. The average HU values (AHUVs) and maximum HU values (MHUVs) of the nodules were measured on noncontrast CT. The distribution of AHUVs and MHUVs in benign and malignant nodules with coarse calci fi cations was analyzed using the Mann – Whitney test. Receiver operating characteristic (ROC) curves were used to identify the best cut-off values. Diagnostic performances were assessed according to the area under the ROC curve (AUC), sensitivity and speci fi city.

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How do stone attenuation and skin-to-stone distance in computed tomography influence the performance of shock wave lithotripsy in ureteral stone disease?

How do stone attenuation and skin-to-stone distance in computed tomography influence the performance of shock wave lithotripsy in ureteral stone disease?

and approved by the Local Ethics Committee of St. Gallen (EKSG 15/055). Written informed consent for data analysis was obtained. NCCT was performed before treatment using a multidetector row helical CT scanner (Siemens, Definition Flash, Forchheim, Germany) with 30–460 mA, 120 kV and 2 mm collimation in every pa- tient. As suggested in a study by Eisner et al. [9], stone size and Hounsfield Unit (HU) measurements were obtained in a standard bone window (window width-1,120 and win- dow level-300). The image with the largest stone diameter was used to define maximum stone size. MAV was obtained by measuring the mean HU of defined regions of interest just smaller than the stone in magnified images without including adjacent soft tissue on each slice of the axial planes (Fig. 1). SSD was calculated as described by El Nahas et al. [3] and the distances at 0°, 45° and 90° were measured using radiographic calipers (Fig. 2). The average was calculated as the SSD. The measurements were per- formed analogous in prone position when targeting pelvic stones. The SSD was also measured and evaluated at an angle of 90° separately, as this seems to be the most im- portant angle in the setting of the SLX-F2 (Storz Medical, Tägerwilen, Switzerland) which was used to perform SWL under sedoanalgesia.

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A new functional method to choose the target lobe for lung volume reduction in emphysema &ndash; comparison with the conventional densitometric method

A new functional method to choose the target lobe for lung volume reduction in emphysema &ndash; comparison with the conventional densitometric method

The novel Syngo CT Pulmo 3D software (Siemens Healthcare) was used for the quantitative CT evaluation (CT- histography) of the lung tissue. First, the three-dimensional CT data set was applied to automatic lung detection (threshold value, - 500 Hounsfield unit [HU]) without major bronchi and vessels. Subsequently lung lobes were semi-automatically segmented using distance measurements between the lobar vessel trees and automatic fissure detection. All lobe borders were validated and, if necessary, corrected manually by an experienced physician. Finally, for each lobe (excluding the middle lobe, as it is not a target for lung volume reduction), mean lung density (MLD) in HU, low attenuation value (LAV) as percentage of lung tissue with HU below - 950, and 15th percentile of HU (15%P) were calculated on maximal inspiration and maximal expiration.

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Utility of virtual monoenergetic images from spectral detector computed tomography in improving image segmentation for purposes of 3D printing and modeling

Utility of virtual monoenergetic images from spectral detector computed tomography in improving image segmentation for purposes of 3D printing and modeling

Accurate segmentation of desired anatomy from imaging data for the purposes of 3D printing requires using a combination and variety of software tools [1, 2, 4]. All three of the most common semi-automated segmenta- tion tools, global thresholding, edge detection, and re- gion growing, rely on voxel Hounsfield Unit values to differentiate between different tissues and surrounding anatomical structures [5]. Even manual segmentation tools such as cropping and sculpting count on visual acuity to see the greyscale differences between the target anatomy. SDCT provides both conventional and VMI

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3-phase dual-energy CT scan as a feasible salvage imaging modality for the identification of non-localizing parathyroid adenomas: a prospective study

3-phase dual-energy CT scan as a feasible salvage imaging modality for the identification of non-localizing parathyroid adenomas: a prospective study

Although our investigation did not reveal a role for the DECT virtual unenhanced images for PA localization, post-hoc spectral Hounsfield unit attenuation curve ana- lysis demonstrated a difference in the characteristics of PAs compared to lymph nodes on arterial phase images (Fig. 5). Arterial phase images are one of the most import- ant acquisitions in 4D-CT performed for PA localization and these preliminary observations suggest that DECT can further increase accuracy during this phase of the exam, which may in turn enable further reduction of the number of acquisitions without decreasing diagnostic ac- curacy in the future. Other potential applications of DECT could be improved PA visualization on low energy virtual monochromatic images and the use of estimated iodine content for PA identification (Fig. 2). These are topics of great interest for future research.

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Hu Shih and female emancipation in China

Hu Shih and female emancipation in China

is to develop one's own ability without another's help. One can live by oneself and work for society".^ The traditional Chinese concept was that women should manage the homekeeping: “The husband handles outside affairs and the wife keeps house” . ^ In common speech the wife calls her husband "the outside one” , while the husband calls his wife "the inner helper” . This distinction is certainly not recognized by the modern American woman, who is rather of the opinion that men and women are all “human beings", and should all aim at making them­ selves really independent "persons” , with no nonsense about ’inside’ and ’outside*.“ Hu Shih cited as examples a woman who graduated from the Department of Forestry and an aviatrix who broke flying records; and spoke at length of a woman's role in American social and political activities. ”1 lived in America for seven years, and felt that nothing significant happened tnere without women being involved. There was no movement of value without innumerable enthusiastic women devoting money and energy to it's furtherance.... Furthermore, as regards religious affairs, charitable works, literary, artistic and musical activities etc., the most enthusiastic in advocating and assisting all of these are w o m e n " . ^ He discussed the contribution of American women to the “Social Settlement” movement. This movement had as its main purpose the establishment of model dwelling houses in working class areas and the promotion of activities such as debating societies, sport, music, 'after-school' courses, medical care and nursing, to

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Testing the planetary models of HU Aquarii

Testing the planetary models of HU Aquarii

Several explanations for these eclipse time variations have been offered in the literature. Similar variations have been seen in a number of other binaries, leading Applegate (1992) to propose a theory that has since become known as Applegate’s mechanism. It assumes that the M-dwarf expe- riences Solar-like magnetic cycles that couple to the binary’s orbital period, by affecting the gravitational quadrupole mo- ment of the M-dwarf, and therefore cause genuine mod- ulations of the orbital period. However, for HU Aqr, the energy available in the M-dwarf is insufficient to explain the large variations observed (Schwarz et al. 2009). A sec- ond explanation for the eclipse time variations is that they are caused by the presence of planet-like or brown dwarf- like bodies in wide orbits around the binary. The additional mass causes periodic shifts in the binary’s centre of mass, which are reflected in the eclipse times (Marsh et al. 2014). This theory has gained popularity after the discovery of cir- cumbinary planets around double main-sequence star bina- ries (e.g. Welsh et al. 2012; Orosz et al. 2012), and mod- els with 1, 2 and even 3 planets have been proposed for HU Aqr (Goździewski et al. 2012; Qian et al. 2011). All have since been disproved on grounds of dynamical instability (Wittenmyer et al. 2012; Horner et al. 2011) or by new data (this paper, Schwope & Thinius 2014; Goździewski et al. 2012).

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Material Selection for Constructing an Intraoral Stent Used in Radiotherapy: Analysis of Density and Structure

Material Selection for Constructing an Intraoral Stent Used in Radiotherapy: Analysis of Density and Structure

characteristics that are biocompatible with human tissue and that are strong enough to construct an intraoral stent. The stent would be used to mechanically isolate the palate, tongue, and mouth floor to prevent radiation in head and neck cancer cases requiring radiotherapy, thereby aiming to decrease the treatment’s side effects. The following materials were selected to be submitted to a first analysis by computed tomography: polyacetal (white and black), polymethylmethacrylate (PMMA), polyurethane, and polyvinyl chloride. By observing the density through Hounsfield unit (HU) analysis, the materials with HU values closest to that of water (HU = 0) were selected for the structural analysis after the radiotherapeutic protocol through micro Raman spectroscopy. After undergoing radiation, PMMA with HUs of 177 and 179 without structural modification had the best density results; this was verified by micro Raman spectroscopy. PMMA seems to be a promising material due to its density and structural integrity after the radiotherapeutic protocol.

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Correlation of Defoliation Timing Methods to Optimize Cotton Yield, Quality, and Revenue

Correlation of Defoliation Timing Methods to Optimize Cotton Yield, Quality, and Revenue

Nodes above cracked boll (NACB) is a technique that is based on the principles of plant monitoring and average HU accumulation to determine when a plant is ready for harvest-aid application. NACB refers to the number of main stem nodes between the uppermost first position cracked boll and the last harvestable boll on the plant. Data from field tests in California, Oklahoma, Texas, and Mississippi concluded that defoliation of cotton at a NACB of equal to or less than 4 resulted in a yield loss of less than 1% and no reduction in fiber quality (Kerby et al., 1992). For the NACB method to be accurately used, the final bloom date for the last effective boll population must be determined.

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Selection bias: neighbourhood controls and controls selected from those presenting to a Health Unit in a case control study of efficacy of BCG revaccination

Selection bias: neighbourhood controls and controls selected from those presenting to a Health Unit in a case control study of efficacy of BCG revaccination

likely to be cooperative. We found that Health Unit attenders controls had a higher coverage of BCG revacci- nation than neighbourhood controls, therefore producing an overestimate of the protective effect of revaccination when compared to the RCT results [14]. The increased vaccine coverage in Health Unit attenders could be a result of their being registered: in this case registration in itself would indicate greater health awareness and willingness to be vaccinated. A more likely explanation is that the Health Units offer BCG vaccination to those who attend the health service for other reasons, and attenders have a higher rate of contact with the service in the past than those just registered there. Selecting Health Unit attenders controls lead to a distortion in the estimate of the protec- tive effect of revaccination with BCG, as the frequency of revaccination in this group was greater than in neighbour- hood controls and cases. Hospital or Health Unit based studies on the protective effect of vaccines, which disre- gard the role of these services in the delivery of vaccina- tion, may be vulnerable to bias. In our study this point

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A Flexible Fourier Form Nonlinear Unit Root Test Based on ESTAR Model

A Flexible Fourier Form Nonlinear Unit Root Test Based on ESTAR Model

In this study, the method proposed by Christopoulos and Leon-Ledesma (2010) was expanded. The proposed new test procedure uses the Fourier function to model structural breaks and allows for the ESTAR type nonlinearity using the nonlinear unit root test proposed by Hu and Chen (2016). Thus, the proposed test not only allows for nonlinearity but also take into account the presence of multiple smooth temporary breaks.

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Emergency Short Stay Unit as an Effective Alternative to In Hospital Admission for Acute Exacerbation of Chronic Heart Failure

Emergency Short Stay Unit as an Effective Alternative to In Hospital Admission for Acute Exacerbation of Chronic Heart Failure

Three patient groups were studied. The EDSSU group (Group 1) consisted of adults with acute exacerbation of chronic heart failure visited in the ED between January 1, 2008 and December 31, 2012, and admitted to an emergency department short-stay unit after their emergency visits. The other two groups comprised adults with the same diagnosis visited during the same period of time and admitted to conventional hospital units (HU), ei- ther internal medicine (Group 2) or cardiology (Group 3) wards, after their emergency visits.

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β Hausdorff Operator on Lipschitz Space in the Unit Polydisk

β Hausdorff Operator on Lipschitz Space in the Unit Polydisk

In this paper, we define β-Hausdorff operator on the unit polydisk and study the boundedness of the operator on Lipschitz space. Firstly, we translate the problem of coefficient into integral of weighted composition operator, then give the sufficient conditions of boundedness, and also ob- tain an upper bound for the operator norm on Lipschitz space.

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Financial Instruments for Enterprises - Final Report : Ex post evaluation of Cohesion Policy programmes 2007 - 2013, focusing on the European Regional Development Fund (ERDF) and the Cohesion Fund (CF)

Financial Instruments for Enterprises - Final Report : Ex post evaluation of Cohesion Policy programmes 2007 - 2013, focusing on the European Regional Development Fund (ERDF) and the Cohesion Fund (CF)

Appraisal of the operational objectives of OP priorities within which FIs were implemented suggests that almost all of them were achieved, 70% to a high degree. For the strategic objectives (related to the regional economy or the SME sector), the appraisal was positive for fewer than half. For the majority of objectives, assessment of the FI contribution was impossible due to lack of data. However, FIs clearly improved access to finance for many enterprises (FIs under the Economic Growth OP reached over 7% of all SMEs in Lithuania), thus achieving an objective stipulated in almost every case study OP. Analysis of OP contributions shows that out of €10.5 billion paid to holding funds and specific funds, only €615 million (less than 6%) came from private sources. However, it is important to note that: not all OPs allow for private contributions; and that private funds maybe attracted ‘downstream’, but are not necessarily captured in the data collected by MAs. This partly accounts for the wide variations between countries, with the UK attracting relatively significant inputs from the private sector (more than 60% of the total across all stocktake countries), and smaller sums in France and Portugal. Some countries attract no private funding as part of OP contribution (e.g. BE, HU, LT). Some €400 million in private capital was attracted through equity FIs, mainly in the UK. The capacity to attract private funds for venture capital improved markedly during the period. Leverage 4 varies widely in the case study OPs, ranging from 20.4 under the OP Bavaria

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Analytical Image Fusion in the Detection of Intrahepatic Hepatocellular Cancer

Analytical Image Fusion in the Detection of Intrahepatic Hepatocellular Cancer

In this paper, we present an analytical fusion approach whose goal is to im- prove the contrast between lesions and normal liver by utilizing information from the CT part of the PET/CT. This information is the density of the lesions or the normal liver expressed as Hounsfield Units (HU). HCC lesions have gen- erally a lower HU value than normal liver [10]. The lesion SUV would relatively increase by the division by the lesion HU and the normal liver SUV would rela- tively decrease by a division by the normal liver HU. The operation would result in increased contrast.

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Clinical utility of computed tomography Hounsfield characterization for percutaneous nephrolithotomy: a cross-sectional study

Clinical utility of computed tomography Hounsfield characterization for percutaneous nephrolithotomy: a cross-sectional study

HU values were also correlated with peri-operative data. Our study shows that the higher the HUD, the shorter the hospitalization time. This result is in line with generally lower complication rates for hyperdense calculi, as described by CROES [20]. In contrast, the need for transfusion was directly related to HUD values, consistent with the data of Gücük et al. who reported a larger decrease in hemoglobin in cases of high HUM [14]. This can be explained by the energy needed to break hard stones into fragments, which can increase the risk of mucosal damage.

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Three-dimensional reconstruction of coronary arteries and plaque morphology using CT angiography – comparison and registration with IVUS

Three-dimensional reconstruction of coronary arteries and plaque morphology using CT angiography – comparison and registration with IVUS

scanners (i.e. CARE kV Siemens Healthcare). RRT auto- matically optimizes the medium contrast dose and the X-ray tube voltage for each individual [33]. A significant reduction on the CTA tube voltage (up ton100 kV) is associated with a significant reduction in radiation ex- posure [34], a lower dosage of medium contrast and higher contrast enhancement in the produced CTA im- ages [35]. Changing the tube voltage of the CTA scanner, the HU values change as well. Therefore, the expected change in HU values by a possible tube voltage reduc- tion may affect the manually point selection of inexperi- enced users. Although, a significant reduction of the tube voltage (up to 100 kV) will increase the image noise as well as contrast-to-noise ratio, it will not impair diagnostic image quality [34]. On the contrary, when re- ducing the tube voltage (up to 100 kV) we have an in- crement of the blooming artifacts created from dense structures (stents) which may preclude an accurate lumen detection [36]. In all CTA scanners the blooming effect results from beam hardening and causes the stent struts to overlap the vessel lumen. Currently, when the methodology is applied in stented segments erroneous CP objects are detected due to stent's blooming effect. Therefore, circular CP objects detected by the method are considered as stents and these segments are not in- cluded in the final outcome. Similarly, the results of bi- furcated segments are not included in the final outcome

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