Dual-Energy Subtraction X-Ray Digital Tomosynthesis: Basic Physical Evaluation

The present study was performed to determine the potential of applying dual-energy subtraction (DES) digital tomo-synthesis to basic physical evaluations. Volumetric X-ray DES digital tomosysnthesis was used to obtain an image of a detectability phantom (an artificial lesion). The image quality of DES digital tomosynthesis was compared to that of DES radiography. The purpose of this study was to determine enhanced visibility quantified in terms of the contrast- to-noise ratio, figure-of-merit, and root-mean-square error. In the in-focus plane, the image quality is better by DES digital tomosynthesis than by DES radiography. The potential usefulness of DES digital tomosynthesis for evaluating a detectability phantom was demonstrated. Further studies are required to determine the ability of DES digital tomosyn-thesis to quantify the spatial relationships between the artificial lesion components of these devices, as well as to iden- tify lesions with diagnostic consequences.

How Prime Numbers Are Interconnected and Built with Two Equations: Addition and Subtraction Rules the Function (6µ)

Are all prime numbers linked by four simple functions? Can we predict when a prime will appear in a sequence of primes? If we classify primes into two groups, Group 1 for all primes that appear before ζ (such that , for instance 5, ), an even number divisible by 3 and 2, and Group 2 for all primes that are after ζ (such that , for instance 7), then we find a simple function: for each prime in each group, , where n is any natural number. If we start a sequence of primes with 5 for Group 1 and 7 for Group 2, we can attribute a μ value for each prime. The μ value can be attributed to every prime greater than 7. Thus for Group 1, and . Using this formula, all the primes appear for , where μ is any natural number.

Left atrial appendage occluder detachment treated with transthoracic ultrasound combined with digital subtraction angiography guided catcher:A case report

BACKGROUND There are very few cases of cardiac occluder detachment,and it is rare to completely remove the occluder using interventional methods without undergoing thoracotomy surgery after detachment.This case innovatively used ultrasound guidance combined with digital subtraction angiography(DSA)to completely remove the occluder,accumulating some experience.CASE SUMMARY The patient underwent left atrial appendage occlusion surgery in our hospital due to atrial fibrillation.After the surgery,the occluder fell off and became free in the left ventricle,which is very dangerous.We innovatively used ultrasound guidance,combined with DSA,and interventional surgery to successfully capture the free occluder using a catcher,completely remove it,and then re implant a new left atrial appendage occluder.After the surgery,the patient recovered very well.CONCLUSION The size selection of the occluder is slightly conservative,and the shape of the left atrial appendage opening is irregular.

Characterization of tumors of jaw:Additive value of contrast enhancement and dual-energy computed tomography

BACKGROUND Currently,the differentiation of jaw tumors is mainly based on the lesion’s morphology rather than the enhancement characteristics,which are important in the differentiation of neoplasms across the body.There is a paucity of literature on the enhancement characteristics of jaw tumors.This is mainly because,even though computed tomography(CT)is used to evaluate these lesions,they are often imaged without intravenous contrast.This study hypothesised that the enhancement characteristics of the solid component of jaw tumors can aid in the differentiation of these lesions in addition to their morphology by dual-energy CT,therefore improving the ability to differentiate between various pathologies.AIM To evaluate the role of contrast enhancement and dual-energy quantitative parameters in CT in the differentiation of jaw tumors.METHODS Fifty-seven patients with jaw tumors underwent contrast-enhanced dual-energy CT.Morphological analysis of the tumor,including the enhancing solid component,was done,followed by quantitative analysis of iodine concentration(IC),water concentration(WC),HU,and normalized IC.The study population was divided into four subgroups based on histopathological analysis-central giant cell granuloma(CGCG),ameloblastoma,odontogenic keratocyst(OKC),and other jaw tumors.A one-way ANOVA test for parametric variables and the Kruskal-Wallis test for nonparametric variables were used.If significant differences were found,a series of independent t-tests or Mann-Whitney U tests were used.RESULTS Ameloblastoma was the most common pathology(n=20),followed by CGCG(n=11)and OKC.CGCG showed a higher mean concentration of all quantitative parameters than ameloblastomas(P<0.05).An IC threshold of 31.35×100μg/cm^(3) had the maximum sensitivity(81.8%)and specificity(65%).Between ameloblastomas and OKC,the former showed a higher mean concentration of all quantitative parameters(P<0.001),however when comparing unilocular ameloblastomas with OKCs,the latter showed significantly higher WC.Also,ameloblastoma had a higher IC and lower WC compared to“other jaw tumors”group.CONCLUSION Enhancement characteristics of solid components combined with dual-energy parameters offer a more precise way to differentiate between jaw tumors.

Digital subtraction angiography for the analysis of supraaortic vessels: What is its role nowadays?

For about 50 years, angiography represented the only imaging method for studying carotid arteries in order to detect the presence of pathological stenosis due to atherosclerotic plaque. Recently, thanks to the use of non-invasive methods, physicians are able to study and quantify the presence of carotid atherosclerosis in vivo These procedures have enabled the introduction of new concepts: (1) the degree of carotid stenosis is approxi- mate to the volume and extension of carotid plaque; and (2) a set of parameters, easily identifiable by com- puted tomography angiography, magnetic resonance angiogram and ultra-sound echo-color Doppler, are closely linked to the development of ischemic symptoms and can significantly increase the risk of stroke regard- less of the degree of stenosis. In light of these findings vulnerable plaques should be identified early, and the role of Digital Subtraction Angiography which is a purely technical luminal technique should be determined.

Spinal pedicle subtraction osteotomy for fixed sagittal imbalance patients

In addressing spinal sagittal imbalance through a posterior approach, the surgeon now may choose from among a variety of osteotomy techniques. Posterior column osteotomies such as the facetectomy or Ponte or Smith-Petersen osteotomy provide the least correction, but can be used at multiple levels with minimal blood loss and a lower operative risk. Pedicle subtraction osteotomies provide nearly 3 times the per-level correction of Ponte/Smith-Petersen osteotomies; however, they carry increased technical demands, longer operative time, and greater blood loss and associated significant morbidity, including neurological injury. The literature focusing on pedicle subtraction osteotomy for fixed sagittal imbalance patients is reviewed. The longterm overall outcomes, surgical tips to reduce the complications and suggestions for their proper application are also provided.

Motion Tracking with Fast Adaptive Background Subtraction

To extract and tr ack moving objects is usually one of the most important tasks of intelligent video surveillance systems. This paper presents a fast and adaptive background subtraction algorithm and the motion tracking process using this algorithm. The algorithm uses only luminance components of sampled image sequence pixels and models every pixel in a statistical model. The algorithm is characterized by its ability of real time detecting sudden lighting changes, and extracting and tracking motion objects faster. It is shown that our algorithm can be realized with lower time and space complexity and adjustable object detection error rate with comparison to other background subtraction algorithms. Making use of the algorithm, an indoor monitoring system is also worked out and the motion tracking process is presented in this paper. Experimental results testify the algorithm's good performances when used in an indoor monitoring system.

Identification of Differentially Expressed Genes in Sweetpotato Storage Roots Between Kokei No.14 and Its Mutant Nongdafu 14 Using PCR-Based cDNA Subtraction

The contents of earotenoids in the storage root of sweetpotato, Ipomoea batatas （L.） Lam. vary dramatically among different cultivars. However, so far little is known about the regulation of carotenoids synthesis in sweetpotato. In our laboratory, we identified a novel sweetpotato mutant, Nongdafu 14, which is a homogenous mutant derived from the wild type Kokei No. 14. The contents of carotenoids in the storage root of Nongdafu 14 were analyzed using high performance liquid chromatography （HPLC）, and it was found that the amount of carotenoids, [3-carotene, lutein and zeaxantion, three major types of earotenoids in sweetpotato storage roots, increased 2-26 folds in Nongdafu 14 compared to Kokei No. 14. Suppression subtractive hybridization （SSH） was used to identify genes that were differentially expressed in Nongdafu 14, and a differentially expressed eDNA library was constructed using the eDNA of Nongdafu 14 storage roots as tester and that of Kokei No. 14 storage roots as driver. Out of the 1 530 clones sequenced, we identified 292 nonredundant ESTs. GO and KEGG analyses of these differentially expressed ESTs indicated that diverse metabolism pathways were affected and candidate genes involved in regulation of carotenoids synthesis are suggested.

Modified magnetic resonance angiography of the liver using sensitivity encoding in comparison with digital subtraction angiography and CT arterial portography

BACKGROUND: Over 355 patients have received ortho- topic liver transplantation ( OLT) at this hospital since 1993. Preoperative imaging studies of both hepatic vessels and parenchyma in these recipients bettered surgical plan- ning or even precluded the necessity of surgery. Here we report our preliminary results of modified magnetic reso- nance angiography ( MRA ) using sensitivity encoding ( SENSE) through comparative study with conventional digital subtraction angiography (DSA) and CT arterial por- tography (CTAP). METHODS: Sixteen patients with suspected liver diseases were included in the study. All of them received both dy- namic MRI of the liver using SENSE and digital DSA with CTAP within a two-week interval. The four-phase MRA was reconstructed from source images of the coronal dy- namic study. The arterial phase of the modified MRA was compared with DSA in the evaluation of hepatic arteries and the portal phase compared with CT portography recon- structed from source images of CTAP. In dynamic study of the liver, a fixed dose (20 ml) of contrast medium and scan timing were used. RESULTS: The main branches and variations of the hepatic arterial system were well shown on the modified MRA, al- though the marginal branches of hepatic arteries were of poor quality. The figures of portal veins on MRA were as clear as or superior to those of CTAP. In addition, the su- prarenal inferior vena cava (IVC) was well demonstrated on MRA and/or non contrast-enhanced coronal balanced fast-field echo (b-FFE) scan sequence in most cases. MRI detected most parenchymal lesions of the liver and hemo- dynamics of these lesions could be evaluated on source ima- ges of the modified MRA. MRI/MRA also serendipitously revealed several extrahepatic disease entities or variations that were not found on DSA/CTAP. CONCLUSIONS: The modified MRA using SENSE is a cost-effective modality of examination for the demonstra- tion of the whole hepatic vascular system. Combined with MRI, it has the potential as a one-stop imaging modality in the preoperative evaluation in fields such as OLT.

Noise Removal in Speech Processing Using Spectral Subtraction

Spectral subtraction is used in this research as a method to remove noise from noisy speech signals in the frequency domain. This method consists of computing the spectrum of the noisy speech using the Fast Fourier Transform (FFT) and subtracting the average magnitude of the noise spectrum from the noisy speech spectrum. We applied spectral subtraction to the speech signal “Real graph”. A digital audio recorder system embedded in a personal computer was used to sample the speech signal “Real graph” to which we digitally added vacuum cleaner noise. The noise removal algorithm was implemented using Matlab software by storing the noisy speech data into Hanning time-widowed half-overlapped data buffers, computing the corresponding spectrums using the FFT, removing the noise from the noisy speech, and reconstructing the speech back into the time domain using the inverse Fast Fourier Transform (IFFT). The performance of the algorithm was evaluated by calculating the Speech to Noise Ratio (SNR). Frame averaging was introduced as an optional technique that could improve the SNR. Seventeen different configurations with various lengths of the Hanning time windows, various degrees of data buffers overlapping, and various numbers of frames to be averaged were investigated in view of improving the SNR. Results showed that using one-fourth overlapped data buffers with 128 points Hanning windows and no frames averaging leads to the best performance in removing noise from the noisy speech.

Superiority of Digital Subtraction for Analysis of Simultaneously-Acquired Dual-Radiopharmaceutical Parathyroid Scintigraphy

With dual-radiopharmaceutical (DR) parathyroid scintigraphy, imaging with 99mTcO4-or 123I-NaI is combined with 99mTc-sestamibi scintigraphy for localization of parathyroid adenomas. The set images are then either visually compared or digitally subtracted to aid in interpretation. While both EANM and SNMMI guidelines recommend use of digital subtraction over visual interpretation alone, to date, the few formal comparisons performed have not demonstrated superiority. The purpose of this investigation is to rigorously assess the added value of digital subtraction over visual interpretation alone using simultaneously-acquired 123I-NaI and 99mTc-sestamibi images. Materials: 90 consecutive patients with DR parathyroid scintigraphy for primary hyperparathyroidism who underwent successful parathyroidectomy were included. DR planar acquisition was performed 15 minutes post injection using 10% dual energy windows. Digital subtraction was subsequently performed using commercially available software. Images were independently reviewed by 3 nuclear medicine trainees and 2 experienced nuclear medicine physicians with and without digital subtraction. Results were compared with surgical and histopathologic findings, which served as ground truth. Results: 90 patients had a total of 91 confirmed parathyroid lesions. All 5 readers had significantly greater sensitivity with digital subtraction compared with visual interpretation alone while specificity was not significantly diminished. Area under the ROC curve was significantly greater with digital subtraction in 3 of 5 readers. Agreement was greater among trainees and experienced physicians when using digital subtraction. Conclusion: Using an optimized DR planar co-imaging technique, digital subtraction significantly improved inter-observer agreement and confidence of interpretation and increased sensitivity, without diminishing specificity.

Adaptive multiple subtraction using a constrained L1-norm method with lateral continuity

一次波L1范数最小化的多次波自适应相减方法,简称L1方法,是基于匹配滤波器设计的多次波自适应相减算法中的一种常用方法。当一次波和多次波混杂在一起时,L1方法有时会伤害一次波,导致一次波同相轴的连续性变差。本文利用预测误差滤波器度量一次波同相轴的连续性,在L1方法的基础上,提出一种能够在压制多次波的同时,尽量保持一次波同相轴连续性的多次波自适应相减算法,简称连续性约束L1方法。利用Pluto模型数据进行多次波相减的结果表明,连续性约束L1方法能够在有效压制多次波的同时,更好地保护一次波。

Single-Channel Speech Enhancement Based on Improved Frame-Iterative Spectral Subtraction in the Modulation Domain

Aiming at the problem of music noise introduced by classical spectral subtraction,a shorttime modulation domain(STM)spectral subtraction method has been successfully applied for singlechannel speech enhancement.However,due to the inaccurate voice activity detection(VAD),the residual music noise and enhanced performance still need to be further improved,especially in the low signal to noise ratio(SNR)scenarios.To address this issue,an improved frame iterative spectral subtraction in the STM domain(IMModSSub)is proposed.More specifically,with the inter-frame correlation,the noise subtraction is directly applied to handle the noisy signal for each frame in the STM domain.Then,the noisy signal is classified into speech or silence frames based on a predefined threshold of segmented SNR.With these classification results,a corresponding mask function is developed for noisy speech after noise subtraction.Finally,exploiting the increased sparsity of speech signal in the modulation domain,the orthogonal matching pursuit(OMP)technique is employed to the speech frames for improving the speech quality and intelligibility.The effectiveness of the proposed method is evaluated with three types of noise,including white noise,pink noise,and hfchannel noise.The obtained results show that the proposed method outperforms some established baselines at lower SNRs(-5 to +5 dB).

Detection of hypervascular hepatocellular carcinoma: Comparison of multi-detector CT with digital subtraction angiography and Lipiodol CT

AIM: The purpose of this study was to compare the diagnostic accuracy of biphasic multi-detector row helical computed tomography (MDCT), digital subtraction angiography (DSA)and Lipiodol computed tomography (CT) in detection of hypervascular hepatocellular carcinoma (HCC).METHODS: Twenty-eight patients with nodular HCC underwent biphasic MDCT examination: hepatic arterial phase (HAP) 25 s and portal venous phase (PVP) 70 s after injection of the contrast medium (1.5 mL/kg). They also underwent hepatic angiography and intra-arterial infusion of iodized oil. Lipiodol CT was performed 3-4 wk after infusion. MDCT images were compared with DSA and Lipiodol CT images for detection of hepatic nodules.RESULTS: The three imaging techniques had the same sensitivity in detecting nodules ＞20 mm in diameter. There was no significant difference in the sensitivity among HAP-MDCT, Lipiodol CT and DSA for nodules of 10-20 mm in diameter. For the nodules ＜10 mm in diameter, HAP-MDCT identified 47, Lipiodol CT detected 27 (X2= 11.3, P= 0.005＜0.01, HAP-MDCT vs Lipiodol CT) and DSA detected 16(X2= 9.09, P= 0.005＜0.01 vs Lipiodol CT and X2= 29.03,P = 0.005＜0.01 vs HAP-MDCT). However, six nodules ＜10 mm in diameter were detected only by Lipiodol CT.CONCLUSION: MDCT and Lipiodol CT are two complementary modalities. At present, MDCT does not obviate the need for DSA and subsequent Lipiodol CT as a preoperative examination for HCC.

Background Subtraction and Frame Difference Based Moving Object Detection for Real-Time Surveillance

A new real.time algorithm is proposed in this paper for detecting moving object in color image sequences taken from stationary cameras. This algorithm combines a temporal difference with an adaptive background subtraction where the combination is novel. When changes occur, the background is automatically adapted to suit the new conditions. For the background model, a new model is proposed with each frame decomposed into regions and the model is based not only upon single pixel but also on the characteristic of a region. The hybrid presentation includes a model for single pixel information and a model for the pixel's neighboring area information. This new model of background can both improve the accuracy of segmentation due to that spatial information is taken into account and saliently speed up the processing procedure because portion of neighboring pixel can be selected into modeling. The algorithm was successfully used in a videosurveillance system and the experiment result shows it can obtain a clearer foreground than the single frame difference or background subtraction method.

Head dual energy-computed tomography angiography versus neuro-digital subtraction angiography

Dual-energy X-ray absorptiometry provides two modes of head computed tomography （CT） angiography scanning： neuro-digital subtraction angiography and dual-energy CT angiography （DE-CTA）. Previous studies have compared image quality, radiation exposure, and bone removal between neuro-digital subtraction angiography and DE-CTA. However, the number of cases was relatively small. The present study examined 300 suspected cases of cerebrovascular disease and observed the methods and duration of post-processing, examination time, and data volume. Results demonstrated similar image quality between the two methods, but lower radiation doses and shorter examination time in DE-CTA. DE-CTA allowed for faster and more stable scanning performance and post-processing methods, facilitating accurate and direct diagnosis of cerebrovascular disease.

Multiple subtraction method based on a non-causal matching filter

在正常多信道的匹配过滤器使用的过滤器操作员身体上是可实现的。这个过滤器操作符仅仅在过滤进程推迟地震数据。noncausal 多信道的匹配过滤器基于一个最少的广场标准被建议解决在哪个预言多重模型数据比真实数据迟了的问题。原因、非原因的多信道的匹配过滤器之间的差别用一个合成射击集合被比较，它表明非原因的匹配过滤器的有效性。另外，滑动随着偏移量和层速度变化的窗户的可变长度被建议解决与在滑动窗户的固定长度增加偏移量增加的事件的计数。滑动窗口的这可变长度也被介绍进修改并且膨胀的多信道的匹配过滤器。这个方法被用于 Pluto1.5 合成数据集合。非原因的过滤器操作符和可变长度滑动窗户的好处被好多重变细结果表明。

Robust background subtraction in traffic video sequence

For intelligent transportation surveillance, a novel background model based on Marr wavelet kernel and a background subtraction technique based on binary discrete wavelet transforms were introduced. The background model kept a sample of intensity values for each pixel in the image and used this sample to estimate the probability density function of the pixel intensity. The density function was estimated using a new Marr wavelet kernel density estimation technique. Since this approach was quite general, the model could approximate any distribution for the pixel intensity without any assumptions about the underlying distribution shape. The background and current frame were transformed in the binary discrete wavelet domain, and background subtraction was performed in each sub-band. After obtaining the foreground, shadow was eliminated by an edge detection method. Experimental results show that the proposed method produces good results with much lower computational complexity and effectively extracts the moving objects with accuracy ratio higher than 90%, indicating that the proposed method is an effective algorithm for intelligent transportation system.

Interventional digital subtraction angiography for small bowel gastrointestinal stromal tumors with bleeding

AIM:To retrospectively evaluate the diagnostic efficacy of interventional digital subtraction angiography(DSA)for bleeding small bowel gastrointestinal stromal tumors(GISTs).METHODS:Between January 2006 and December2013,small bowel tumors in 25 consecutive patients undergoing emergency interventional DSA were histopathologically confirmed as GIST after surgical resection.The medical records of these patients and the effects of interventional DSA and the presentation and management of the condition were retrospectively reviewed.RESULTS:Of the 25 patients with an age range from34-to 70-year-old(mean:54±12 years),8 were male and 17 were female.Obscure gastrointestinal bleeding,including tarry or bloody stool and intermittent melena,was observed in all cases,and one case also involved hematemesis.Nineteen patients required acute blood transfusion.There were a total of 28 small bowel tumors detected by DSA.Among these,20 were located in the jejunum and 8 were located in the ileum.The DSA characteristics of the GISTs included a hypervascular mass of well-defined,homogeneous enhancement and early developed draining veins.One case involved a complication of intussusception of the small intestine that was discovered during surgery.No pseudoaneurysms,arteriovenous malformations or fistulae,or arterial rupture were observed.The completely excised size was approximately 1.20 to 5.50 cm(mean:3.05±1.25 cm)in maximum diameter based on measurements after the resection.There were ulcerations(n=8),erosions(n=10),hyperemia and edema(n=10)on the intra-luminal side of the tumors.Eight tumors in patients with a large amount of blood loss were treated with transcatheter arterial embolization with gelfoam particles during interventional DSA.CONCLUSION:Emergency interventional DSA is a useful imaging option for locating and diagnosing small bowel GISTs in patients with bleeding,and is an effective treatment modality.

Robust Background Subtraction Method via Low-Rank and Structured Sparse Decomposition

Background subtraction is a challenging problem in surveillance scenes. Although the low-rank and sparse decomposition(LRSD) methods offer an appropriate framework for background modeling, they fail to account for image's local structure, which is favorable for this problem. Based on this, we propose a background subtraction method via low-rank and SILTP-based structured sparse decomposition, named LRSSD. In this method, a novel SILTP-inducing sparsity norm is introduced to enhance the structured presentation of the foreground region. As an assistance, saliency detection is employed to render a rough shape and location of foreground. The final refined foreground is decided jointly by sparse component and attention map. Experimental results on different datasets show its superiority over the competing methods, especially under noise and changing illumination scenarios.