Spiral Technique Research Articles

An Assessment of Cleaning Amenability of Salt Range Coal Through Physical Cleaning Methods

Representative coal samples from the eastern salt range (Modern Engineering and Kishor coal mines, Pakistan) and the central salt range (Punjmin coal mine, Pakistan) were collected and examined for their chemical composition. The chemical characteristics indicate that the salt range coal belongs to sub-bituminous category. Washability analysis on selected coal samples (6.70 ´ 0.212 mm) using zinc chloride solution with a specific gravity from 1.3 to 1.7 were executed. The results classify the central salt range coal as easily washable while, the Eastern salt range coal as moderately difficult to wash. Jigging, shaking table and spiral techniques were applied to check the cleaning amenability of the salt range coal through these techniques. Among these techniques, shaking table revealed the most promising results for all the three coals. Punjmin coal showed the maximum rejection of ash of 55% and that of total sulphur of 74% with a recovery of 46%.

TU-F-CAMPUS-I-01: Investigation of the Effective Dose From Bolus Tracking Acquisitions at Different Anatomical Locations in the Chest for CT

Purpose: Stationary table acquisitions (Bolus tracking) in X-ray Computed Tomography (CT) can Result in dose length products (DLP) comparable to spiral scans. It is today unclear whether or not the effective dose (E) for Bolus Tracking can be approximated using target region specific conversion factors (E/DLP). The purpose of this study was to investigate how E depends on the anatomical location of the Bolus Tracking in relation to Chest CT scans with the same DLP. Methods: Effective doses were approximated for the ICRP 110 adult Reference Male (AM) and adult Reference Female (FM) computational voxel phantoms using software for CT dose approximations (pre-simulated MC data). The effective dose was first approximated for a Chest CT scan using spiral technique and a CTDIvol (32 cm) of 6 mGy. The effective dose from the spiral scan was then compared to E approximated for contiguous Bolus Tracking acquisitions (1 cm separation), with a total collimation of 1 cm, over different locations of the chest of the voxel phantoms. The number of rotations used for the Bolus Tracking acquisitions was adjusted to yield the same DLP (32 cm) as the spiral scan. Results: Depending on the anatomical location of the Bolus Tracking, E ranged by factors of 1.3 to 6.8 for the AM phantom and 1.4 to 3.3 for the AF phantom, compared to the effective dose of the spiral scans. The greatest E for the Bolus Tracking acquisitions was observed for anatomical locations coinciding with breast tissue. This can be expected as breast tissue has a high tissue weighting factor in the calculation of E. Conclusion: For Chest CT scans, the effective dose from Bolus Tracking is highly dependent on the anatomical location where the scan is administered and will not always accurately be represented using target region specific conversion factors.

PTH-041 Large (<4 cm) and giant (≥4 cm) colorectal polyps: comparison of piecemeal resection outcomes

Introduction Piecemeal Endoscopic Mucosal Resection (p-EMR) is a standard and safe endoscopic technique for resection of large colorectal polyps (>2 cm). Limited data are available regarding p-EMR of giant polyps (>4 cm). Method A prospective study recording short and long-term outcomes after p-EMR for colorectal polyps > 2 cm between Jan 2010 and August 2012 was conducted. We compared two cohorts of patients: group-A with large polyps (2 to Results Group-B patients were older than group-A patients (mean 70.6 vs. 67.8 yrs, p = 0.01) and were more likely to have come from a tertiary referral source (p = 0.05). Large polyp referrals were almost twice as frequent as giant polyp referrals (218 vs. 123, p Endoscopic excision was complete in 89% in large (median time 18min) and in 70% in giant groups (median time 38min). All large polyps were excised in one session, whilst 4% of giant polyps required more than one session. Incomplete submucosal lift (46% vs 63%, p = 0.002) and difficult polyp position (45% vs 63%, p Conclusion Piecemeal resection is a safe and efficacious modality for the resection of colorectal polyps >4 cm. However, these giant polyps more often require spiral snare or hybrid resection techniques and their higher adenoma recurrence rate post p-EMR may dictate shorter surveillance intervals. Disclosure of interest None Declared.

The first series of spiral vein graft reconstruction technique for venous resection in borderline operable pancreatic cancer

The first series of spiral vein graft reconstruction technique for venous resection in borderline operable pancreatic cancer

Abstracts of the 2015 SCMR/EuroCMR Joint Scientific Sessions, February 4-7, 2015, Nice, France.

Background While blood flow in the majority of arteries peaks in systole, the rhythmic squeezing of the coronary arteries and microcirculation as the heart beats results in left anterior descending artery (LAD) flow being diastolicpredominant while for the right coronary artery (RCA), there is approximately equal flow in systole and diastole. These temporal flow patterns can provide important information on disease state. The aim of this study is to assess the inter-breath hold reproducibility of parameters of coronary haemodynamics using a high temporal resolution spiral phase velocity mapping technique and to compare automatic and manual analyses.

Concentric rings K-space trajectory for hyperpolarized (13)C MR spectroscopic imaging.

To develop a robust and rapid imaging technique for hyperpolarized (13)C MR Spectroscopic Imaging and investigate its performance. A concentric rings readout trajectory with constant angular velocity is proposed for hyperpolarized (13)C spectroscopic imaging and its properties are analyzed. Quantitative analyses of design tradeoffs are presented for several imaging scenarios. The first application of concentric rings on (13)C phantoms and in vivo animal hyperpolarized (13)C MR Spectroscopic Imaging studies were performed to demonstrate the feasibility of the proposed method. Finally, a parallel imaging accelerated concentric rings study is presented. The concentric rings MR Spectroscopic Imaging trajectory has the advantages of acquisition timesaving compared to echo-planar spectroscopic imaging. It provides sufficient spectral bandwidth with relatively high efficiency compared to echo-planar spectroscopic imaging and spiral techniques. Phantom and in vivo animal studies showed good image quality with half the scan time and reduced pulsatile flow artifacts compared to echo-planar spectroscopic imaging. Parallel imaging accelerated concentric rings showed advantages over Cartesian sampling in g-factor simulations and demonstrated aliasing-free image quality in a hyperpolarized (13)C in vivo study. The concentric rings trajectory is a robust and rapid imaging technique that fits very well with the speed, bandwidth, and resolution requirements of hyperpolarized (13)C MR Spectroscopic Imaging.

Image Hiding Using Zigzag and Spiral Traversal Algorithms

Image hiding techniques are used for embedding a secret image into a cover image. A secret image can be transmitted safely for secure communication in presence of third parties. Each pixel in the secret image is disarranged and adjusted to form a suitable string of bits that can be embedded. These bits are then, embedded into the cover image in corresponding places, and this image would be called stego-image that hides secret data. This paper suggests a new image disarranging technique. Here we have implemented two algorithms, namely, Zigzag traversal technique and Spiral traversal technique. The algorithms have been be applied selectively or in combination for the process of encryption and decryption

Using MRI for Assessing Velopharyngeal Structures and Function

Direct visualization of the velopharynx and, in particular, the levator muscle is particularly important in the assessment of velopharyngeal function and normal speech production. The purpose of this study is to demonstrate the development of a static and dynamic magnetic resonance imaging protocol for evaluation of velopharyngeal structures and function. A high-resolution, T2-weighted turbo-spin-echo three-dimensional anatomical scan (sampling perfection with application optimized contrasts using different flip angle evolution) was used to acquire a large field of view covering the velopharyngeal anatomy. Dynamic speech assessment was obtained using a fast-gradient echo, fast low-angle shot, multi-shot spiral technique to acquire 15.8 frames per second (FPS) of the sagittal and oblique coronal image planes. Using a three-dimensional data set, as opposed to two-dimensional data, the full contour of the levator muscle can be appreciated. Dynamic images were obtained at 15.8 FPS in the sagittal and oblique coronal planes, enabling visualization of the movements of the velum, posterior pharyngeal wall, lateral pharyngeal walls, and levator muscle during speech. A three-dimensional magnetic resonance imaging sequence, such as that used in the present study, may provide better analyses and more precise measurements. A dynamic fast low-angle shot sequence allows for visualization of the levator muscle and the velum during speech at a high image rate. This protocol could have a significant impact in improving the process of visualizing pathology and promoting clinical treatment plans for individuals born with cleft lip and palate.

Clinical Anatomy and Diagnostic Visualization of Emissary Veins

Objective: Emissary veins are often neglected in their clinical relevance. However, at the retrosigmoid approach especially during semisitting positions these transosseous venous connections become potentially live threatening. Therefore, knowledge of presence and the configuration of emissary veins is essentially in the preoperative planning. Methods: A total of 200 consecutive patients planned for the retrosigmoid approach, due to cerebellopontine angle pathology, were evaluated by computed tomography in standard technique (5-mm slices) and spiral technique for the posterior fossa (1-mm slices). The presence and size of emissary veins, entry point in the sigmoid sinus, the predilection side, and the visibility in either CT technique were evaluated. Results: Emissary veins were present in 80% of the patients, varying from 0.3 to 4 mm in diameter, whereas 1% (right)and 2% (left) of the patients have more than one emissary vein, respectively. The mean length of the intraosseous course of the vein to the entry point in the sigmoid sinus was 7.6 mm (right side) and 5.1 mm (left side). The study shows that with standard CT technique only emissary veins larger than 1.0mm can be identified and that either entry point in the skull base or sigmoid sinus cannot be securely visualized. On the other hand, spiral technique CT scans visualized emissary veins of 0.3mm with their exact course from the skull to the entry point in the sigmoid sinus. Conclusions: Thin sliced CT scans are inevitable in the preoperative planning of the retrosigmoid approach to identify the presence and the course of emissary veins, reducing unnecessary morbidity during surgery.

Size Reduction of Octa-Band WWAN/LTE Antenna using Slotted Spirals with Non Uniform Width for Tablets

The effect of slotted spiral technique on an antenna that covers octal bands of WWAN/LTE has been studied and discussed in this paper. The Slotted Spiral consists of strips arranged together forming a spiral of different vertical and horizontal width. The antenna has been initially designed without employing the slotted structure to cover the frequency bands GPS l2 band-1227.60/l3 band 1381.05, DCS1800 /PCS1900/ UMTS2100 LTE2300/2500/2600 (1710–2690 MHz).The size of the antenna was initially 15 x 40 mm.Then the structure has been designed employing the slotted spiral technique which provides a size reduction from 15 x 40 mm to 15 x 38 mm which is small enough to be incorporated in a tablet computer. Furthermore the use of embedded parallel resonant structure aids in implementing slotted spiral technique. The antenna after employing size reduction provided a low return loss and good radiation efficiency and high gain than the antenna without slotted spiral.

CT dose reduction using prospectively triggered or fast-pitch spiral technique employed in cardiothoracic imaging (the CT dose study)

ObjectivesTo establish current radiation dose levels with contemporary scanners capable of prospectively triggered or high-pitch spiral scan modes to previous generation scanners among patients evaluated for coronary artery disease, pulmonary embolism, aortic disease, and “triple rule out” in a large population of patients at multiple centers. BackgroundPrevious small-scale studies with carefully controlled scan protocols report that CT scanners that facilitate prospectively triggered scanning and provide high-pitch spiral CT scan modes drastically lower radiation doses. However, diagnostic reference levels should be selected by medical bodies on the basis of large surveys of representative sites and reviewed at appropriate time intervals. MethodsScan data including dose and image quality parameters were collected retrospectively from 64 slice scanners (control) and prospectively after sites installed 128-slice dual-source scanners with high-pitch capability (study). Protocol selection was purposely not specified to survey “real world” results. Blinded quantitative image analysis was performed on every fifth scan. ResultsFrom April 2011 to March 2012, 2085 patients at 9 sites completed the study: 1051 coronary artery disease (509 control, 542 study), 528 pulmonary embolism (267 control, 261 study), 419 aortic disease (268 control, 151 study), and 87 triple rule out (53 control, 34 study). There was a significant reduction in median dose-length product (DLP) from 669 mGy∙cm (interquartile range [IQR]: 419–1026 mGy∙cm) in the control group to 260 mGy∙cm (IQR: 159–441 mGy∙cm) in the study group, a reduction by 61% (P < .0001) and was lower in all categories. No significant differences were noted in image quality. ConclusionUse of advanced scanners facilitating prospectively triggered or high-pitch spiral scan modes results in marked dose reduction across a variety of cardiovascular studies, with no compromise in image quality. These findings may contribute to new target dose recommendations in societal guidelines.

The spiral aftereffect technique (SAT) can differentiate between depressive and somatoform disorder patients.

This study examined how differences in visuo-perceptual patterns are related to psychopathology. Fifty-six patients (37 women, 19 men; M age = 43.8 yr., SD = 13.4) with a main diagnosis of unipolar depression and 42 patients (22 women, 20 men; M age = 42.0 yr., SD = 11.1) with a main diagnosis of somatoform disorder were compared. The duration and trend of a visual motion aftereffect were measured with the Spiral Aftereffect Technique (SAT). The results indicated that successively increasing aftereffect durations characterized the depressive patients, whereas patterns of very short or short final aftereffect preceded by successively decreasing aftereffect durations characterized the patients with a somatoform disorder. The SAT is thus a valuable tool for linking objectively measured perceptual-personality characteristics with some mental disorders.

QCT and Diagnosis of Osteoporosis

: Noninvasive measurement of bone mineral density (BMD) is a technology that benefits both the patient and society through its potential to decrease the morbidity, mortality, and cost of fractures associated with osteoporosis through early detection and treatment. In general, two sites are assessed, the spine and the hip. If one of these sites cannot be assessed, the protocol should outline the next site to be used. Quantitative computed tomography (QCT) can identify patients with low BMD compared to the QCT reference database and who are at risk for fracture. QCT cannot be used to diagnose osteoporosis based on the quantitative BMD value obtained, since it has never been validated for WHO criteria. It is, however, the only other technology besides DXA that is approved for treatment follow up. Quantitative computed tomography (CT) is a three-dimensional non-projectional technique to quantify bone mineral density (BMD) in the spine, proximal femur, forearm, and tibia with a number of advantages to other densitometric techniques: cortical and trabecular bone can be separated, trabecular volumes of interest (VOI) are largely independent of degenerative changes in the spine; so, QCT can be used to assess/monitor patients with extensive degenerative disc disease, more sensitively than DXA for density changes in the vertebral body and 3D geometric parameters can be determined. Bone mineral density (BMD), as measured by QCT, is a true density measured in g/cm3, in contrast to dual-energy X-ray absorptiometry (DXA), which determines an areal density (BMDa) measured in g/cm2. It has also some disadvantages such as higher radiation dose and lack of applicability with WHO diagnostic criteria, Furthermore, diagnosis of low bone mass is made by using the QCT criteria which is technically more difficult than DXA unless spiral technique is used. In modern spiral CT scanners, various techniques are implemented to significantly reduce radiation exposure by optimally adapting the X-ray tube current to the individual subject being scanned. The level of dose reduction depends on anatomical location. However, due to limited medical evidence, definitive advice on its use in all clinical practices cannot be provided until more data emerge.

Cleaning study of a low-rank lignite with DMS, Reichert spiral and flotation

The cleaning potential of a low-rank lignite coal has been evaluated via dense medium separation (DMS), Reichert spiral and flotation techniques. The washability characteristic of the lignite was investigated with laboratory sink and float tests. Solutions of zinc chloride (ZnCl2) with specific gravities ranging from 1.3 to 1.9 were used as dense medium liquid. The as-received raw lignite sample was sieved into three size fractions (−100+25mm; −25+1.5mm; −1.5mm) and washability characteristics of the former two fractions were separately investigated. The latter fine fraction was cleaned using both DMS and Reichert spiral techniques under different operational parameters. Flotation tests were conducted using the −150μm fraction. Clean coal characteristics and recoveries were determined after each experiment.Elementary ash and ±0.1 relative specific gravity curves showed that this low-rank coal can be classified as “difficult to clean” due to its high content of near-gravity materials at specific gravities lower than 1.7. However, about 50% and 40% of the raw coal (3571kcal/kg) can be obtained as clean coal with calorific values of 5400kcal/kg for the coarse fraction and 5600kcal/kg for the fine fraction, by DMS and Reichert spiral methods, respectively. The ash contents (14–18%) and calorific values (6022–5582kcal/kg) of the cleaned coarse and fine fractions are suitable for use in industry. Low calorific value (about 2500kcal/kg) middling and tailing can be used in properly constructed thermal electric power plants.

Underwater navigation using an acoustic spiral wave front beacon

A spiral wave front beacon consists of an array of transducers which produce a signal whose phase depends on the azimuthal angle at which it is received and a reference signal with constant phase [J. Acoust. Soc. Am. 131, 3748 (2012)]. A vehicle can determine aspect to the beacon by comparing the phase of the two signals. Progress in the development of this navigation technique will be discussed including results from experiments at Dodge Pond in Connecticut where an unmanned surface vehicle determined its aspect to within 10° by receiving signals from the beacon. Also, tests of a new spiral beacon design [J. Acoust. Soc. Am. 130, 2506 (2011)] in laboratory and underwater environments will be presented. Underwater experiments are performed at the Navy’s Seneca Lake facility in upstate New York using an UUV to record signals. Overall, these results demonstrate that intrinsic phase shifts in the beacon can be handled by signal processing at the receiving vehicle and that the spiral navigation technique is robust in reverberant environments. [Work supported by the Office of Naval Research.]

Intracanal placement of calcium hydroxide: a comparison of specially designed paste carrier technique with other techniques

BackgroundThis study compared the effectiveness of a Specially Designed Paste Carrier technique with the Syringe-Spreader technique and the Syringe-Lentulo spiral technique in the intracanal placement of calcium hydroxide.MethodsThree groups, each containing 15 single-rooted human anterior teeth were prepared using standardized Mtwo rotary instruments to a master apical file size 40 with 0.04 taper. Each group was filled with calcium hydroxide paste using: Syringe and #25 finger spreader (Group 1); Syringe and #4 rotary Lentulo spiral (Group 2), Specially Designed Paste Carrier (Group 3). Using pre-filling and post-filling radiographs in buccolingual and mesiodistal planes, the radiodensities at 1 mm, 3 mm, 5 mm, and 7 mm from the apical foramen were analyzed by ANOVA and Bonferroni post hoc tests.ResultsOverall, The Specially Designed Paste Carrier technique showed a statistically significantly higher mean radiodensity than the two other compared techniques. No significant difference was detected between the Syringe-Lentulo spiral and the Syringe-Spreader techniques.ConclusionThe Specially Designed Paste Carrier technique was more effective than the Syringe-Spreader technique and the Syringe-Lentulo spiral technique in the intracanal placement of calcium hydroxide.

Deformation Analysis of Elliptical Cross-Section Spiral Equal Channel Extrusion Technique

Abstract The simplified slice-plain-strain method and the incorporating incremental superposition theory were adopted for the cumulative effective strain (CES) of elliptical cross-section spiral equal-channel extrusion (ECSEE) process. The ECSEE deformation was divided into two basic deformation modes: round-ellipse/ellipse-round cross-section transitional channel deformation and elliptical cross-section torsion transitional channel deformation, through tracking a particle of the cross section. The change laws for the combined CES of the particle with the channel length and the combined effective strain (ES) distribution were obtained by MATLAB software programming, and the results were compared with these via Deform-3D finite element method (FEM). The results show that the ECSEE accumulation torsion strain is greater than that of other forms, and the shear deformation is dominant. The blank cross-section ES presents the gradient decreasing trend from the periphery to the center. The FEM results also verify the accuracy of analytical solution.

Dewatering of Incinerated Sludge Ash Water Slurry with Spiral Cross-Flow Technique

Dewatering of Incinerated Sludge Ash Water Slurry with Spiral Cross-Flow Technique

A Reconfigurable WiMAX Antenna for Directional and Broadside Application

A novel reconfigurable compact patch array antenna for directional and broadside application is proposed. The presented antenna has successfully been able to function for directional beam at 320° or 35° and divisive broadside beam at 43° and 330°. This is realized in the unique form of aperture coupled spiral feeding technique and positioning of the radiating elements at 0°, 90,° and 180°. The switchable feature is effectively performed by the configuration of three PIN diodes. All PIN diodes are positioned at the specific location of the aperture coupled structure. It is discovered in simulation that the switches can be represented with a copper strip line or touchstone (TS) block . The proposed antenna design operates at 2.37 GHz to 2.41 GHz and has a maximum gain of 6.4 dB and efficiency of 85.97%. Such antenna produces a broadside HPBW with a wider bandwidth covering from −90° to 90° compared to the normal microstrip antenna which could only provide HPBW of −50° to 50°. Moreover, the proposed antenna has small physical dimension of 100 mm by 100 mm. The simulation and measurement results have successfully exhibited the idea of the presented antenna performance. Therefore, the antenna is sufficiently competent in the smart WiMAX antenna application.

Myocardial velocity mapping for the right ventricle in pulmonary arterial hypertension using a novel image-based respiratory self-navigation from a golden-angle spiral acquisition

Background CMR is a recognized method of assessing global RV function in patients with pulmonary arterial hypertension (PAH). Unfortunately, assessment of regional myocardial motion with MRI remains challenging due to the thin RV wall. One solution may be tissue phase mapping (TPM) in which motion can be encoded at a higher spatial resolution. However, one problem is the need for respiratory navigation due to long scan times. We have therefore implemented a novel self-gated golden-angle spiral TPM technique that can acquire high-resolution data efficiently during free breathing in healthy volunteers and in patients with PAH. Methods