Spiral Technique Research Articles

A Case of Radiolucent Foreign Body (Temporary Resin Bridge) Aspiration Accompanied by Inflammatory Polyps

Summary This case demonstrates the rare occurrence of a radio-lucent temporary resin bridge aspiration in adults while they are in a conscious and awaken state and the re-sultant formation of inflammatory polyps. Although no unique findings were noted in a chest x-ray, careful his-tory taking accompanied by physical examinations can lead to clinical suspicion of foreign body aspiration in an earlier stage. Moreover, flexible bronchoscopy is a tool useful not only for the evaluation process but also for managing the aspirated foreign material.

Three‐dimensional spiral technique for high‐resolution functional MRI

For high-resolution functional MRI (fMRI) studies, signal-to-noise ratio (SNR) plays an important role. Any method that results in an improvement in SNR will be able to improve the quality of activation maps. Three-dimensional (3D) acquisition methods in general can provide higher SNR than that of 2D methods due to volume excitation. To demonstrate the superiority of 3D methods for high-resolution fMRI scans, a comparison study between 3D and 2D spiral methods was performed using a contrast-reversing checkerboard visual stimulus. A 3-inch surface coil was used to limit the in-plane FOV to 14 cm x 14 cm so that 32 1-mm slices with an in-plane voxel size of 1.1 mm x 1.1 mm could be acquired within 5.76 seconds. Results showed that average numbers of activated voxels were 407 and 841 for 2D and 3D methods, respectively (P < 0.01). Therefore, the 3D technique may be a useful alternative to the conventional 2D method for high resolution fMRI studies.

3D CT Reconstruction in Diagnostics of Coronoid Fractures of the Ulna Bone

An X-ray examination is a basic and final technique in the diagnostics of most elbow region fractures. Coronoid fractures are complicated injuries and need to be carefully evaluated before deciding on the most appropriate course of treatment. In these fractures the identification and location of the broken fragments and their origin create significant difficulties. The main goal of this paper is an evaluation of the usefulness of spiral CT and 3D reconstruction techniques in the diagnostics of complicated fractures of that region. Following analysis of the line of fractures, the injuries were classified in two categories. 11 fractures of the coronoid were analyzed. 3D reconstruction is a very useful method which always helps to obtain the best outcome.

Class‐3c compression bandaging for venous ulcers: comparison of spiral and figure‐of‐eight techniques

This paper reports a study to compare the differences in compression produced on a limb using a spiral and a figure-of-eight bandaging technique. Chronic leg ulcers are a major health problem in Western countries. Compression bandaging is the accepted treatment for venous leg ulcers. The spiral and the figure-of-eight techniques are traditional methods of applying compression bandages. But their performance in terms of pressure profiles is unknown. Despite a lack of evidence about technique, class-3c compression bandages are not currently recommended for application in a figure-of-eight as this is thought to produce dangerously high pressure. A cross-over experimental design was used with a sample of 26 nurse bandagers. Consistency of performance was tested. Bandage stretch and overlap were measured and analysed by standard deviation to ensure that the techniques were consistent and repeatable. Pressure probes were then applied to the medial, posterior and lateral aspects of the lower limb of a healthy volunteer. The class-3c compression bandage was applied using both techniques and the pressure profiles around the leg were measured under the bandage. The results of each technique were compared using independent sample t-tests. The data were collected in 1999. The figure-of-eight technique provided statistically significantly higher compression at lower areas of the leg than the spiral technique. Mean pressure difference was 20.3 mmHg at the ankle, 22.2 mmHg at the gaiter, 9.4 mmHg at the calf. The pressure differences decrease towards the knee with both techniques and decrease more steeply with the figure-of-eight technique. The spiral technique was a safe and comfortable method of bandage application. The figure-of-eight also provided graduated compression but with some high areas of pressure, notably overlying the Achilles tendon. However, before firm practice recommendations are made, replication of the study using a padding layer and a larger sample is needed.

Assessment of Gastric Cancer: Value of Two-phase Multidetector-row Spiral CT Three-dimensional Reconstruction Technique

Objective: To evaluate the diagnostic value of two-phase multidetector-row spiral CT threedimensional reconstruction technique in TNM staging of gastric cancer. Methods: In 29 patients with gastric carcinoma pathologically conformed, plan scans were done firstly. Two-phase spiral CT was performed within one breathhold each. Distension of the stomach was achieved by intravenous application of anisodamine and effervescent granules. After bolus injection of contrast medium, scanning was performed in the arterial and venous phase, and the source images were thin reconstructed. The stomach to three-dimension analysis was constructed by volume rendering (VR) multiplanar volume reconstruction (MPVR), shaded surface display (SSD) and CT virtual gastroscopy (CTVG) technique. In combination with the sources images, gastric tumour invasion and lymph node metastasis was assessed, and TNM staging was performed. Results: In 29 cases of gastric carcinoma, the sensitivity and specificity of two-phase multidetector-row spiral CT three-dimensional reconstruction technique in T1, T2, T3 and T4 staging, the sensitivity and specificity was 50% and 50%, 87.5% and 77.8%, 83.3% and 76.9% and 100% and 80% respectively. For the N staging, the sensitivity and specificity in N0, N1, and N2-N3 was 83.3% and 71.4%, 87.5% and 77.8% and 81.8% and 75% respectively. The sensitivity and the specificity for M1 staging was 100%. Conclusion: The reconstruction technique in combination with 16-slices spiral-CT can perform TNM staging well and effectively guide the choice of the surgical procedures for gastric cancer.

Godfrey N. Hounsfield und die Folgen

On August 12, 2004 Sir Godfrey N. Hounsfield died at the age of 84 years. Computed tomography, which he developed, has been the most important invention in radiology since the discovery of X-rays; it revolutionized the medical diagnostic undisputedly. The essay gives an insight into the personality and the achievments of G. N. Hounsfield as well as the evolution of computed tomography of the classical sequential scanning via single to the current multislice spiral technique. The perspectives of computed tomography are shown.

Surface Electromyography Apparatus as a Measurement Device for Biofield Research: Results from a Single Case Study

Objectives: The objective of this preliminary investigation was to determine if surface electromyography (EMG) equipment is capable of detecting electrical signals that can be used as a measure in biofield research. Design: These preliminary data were collected from one subject (a member of the research team), using the subject as his own control. Resting state data are compared to data collected during a specific Healing Touch (HT) intervention. Settings/location: The setting was in an electromagnetically shielded room (a modular enclosure utilizing two separate conductive electromagnetic barriers, which were electrically isolated, attached by a single-point ground connection) at the University of Wisconsin-Milwaukee, Milwaukee, WI. Intervention: Data were collected during a resting state, and subsequently during a partial "HT back sequence." The back sequence is a standard HT procedure consisting of "Connecting the Lower Body," "Open Spinal Energy Flow," a "Vertebral Spiral Technique," and other techniques taught in HT level 2. Measures: Electrodes were attached to the back of the subject at eight acupoints. The Model 544 EMG System (amplifier and electrode assembly) (Therapeutics Unlimited, Inc. Iowa City, IA) was used to acquire data. The raw data were divided into discrete time segments and converted from the time domain into the frequency domain by performing a fast Fourier transform. Integer frequency averaging was conducted to allow for ease of interpretation. Using the voltages at each frequency, the signal strength was calculated in decibels. Results: A 0-65 Hz frequency spectrum was obtained from the surface EMG apparatus. An averaged baseline, "resting state" frequency spectrum was definable for the subject that was stable with time for signal strengths >0 dB. When the HT practitioner attuned with the subject, higher frequency components of the spectrum increased in amplitude, peaked, then decreased throughout the intervention. Conclusions: The conclusions drawn from these results is that the surface EMG apparatus has potential as a measurement device for biofield research. Further experimentation using this device for biofield measurement is encouraged.

Improving mass measurement of coronary artery calcification using threshold correction and thin collimation in multi-detector row computed tomography: In vitro experiment 1

Rationale and Objectives. This in vitro study was designed to improve the accuracy of coronary calcium mass measurement from computed tomography (CT) images by developing threshold-based calcium CT number correction and thin-slice spiral techniques. Materials and Methods. A cardiac CT phantom containing simulated calcified cylinders of known calcium density was scanned with sequential 4 × 2.5-, spiral 16 × 1.5-, and spiral 16 × 0.75-mm collimation on 4- and 16-detector row CT scanners. The images obtained from the spiral scans were reconstructed in various slice widths. The calcified cylinders were imaged and their mean CT number and size were measured at thresholds ranging from 50 to 390 Hounsfield unit. The calcium mass measured was compared with the actual value to determine errors, and threshold-based correction factors were derived to minimize the errors. Results. The minimum amount of measurable calcium in 1-mm cylinder was 0.3 mg at the 16 × 1.5-mm protocol and 0.2 mg at the 16 × 0.75-mm protocol. Compared with 2.5-mm sequential protocol, thin-slice spiral protocols yielded a higher radiation exposure and lower or similar image noise levels. The error in calcium mass after correction was significantly smaller than that in measured mass ( P < .0001) and was consistent between the imaging protocols ( P = .49). The accuracy of mass measurements was clearly improved by using thin-slice imaging protocols especially in 200-mg/cm 3 calcium density ( P < .0001). Conclusion. The accuracy of calcium mass CT measurement can be improved by threshold-based calcium CT number correction and thin collimation spiral techniques.

Multiplanar reformat display technique in abdominal multidetector row CT imaging

The purpose of this study was to evaluate the image quality and diagnostic value of multiplanar reformat (MPR) of abdominal CT performed with multidetector row spiral technique (MDCT). Forty-five patients were referred for an abdominal MDCT angiography. No significant differences in image quality and in the number of lesions detected were found between axial and MPR images ( t-test, P>.90 and chi-square, P>.95). Additional diagnostic value to axial images could be obtained with MPR display.

Initial experiences with in vivo right coronary artery human MR vessel wall imaging at 3 tesla.

Due to their relatively small size and central location within the thorax, improvement in signal-to-noise (SNR) is of paramount importance for in vivo coronary vessel wall imaging. Thus, with higher field strengths, coronary vessel wall imaging is likely to benefit from the expected "near linear" proportional gain in SNR. In this study, we demonstrate the feasibility of in vivo human high field (3 T) coronary vessel wall imaging using a free-breathing black blood fast gradient echo technique with respiratory navigator gating and real-time motion correction. With the broader availability of more SNR efficient fast spin echo and spiral techniques, further improvements can be expected.

Evaluation of compression therapy: Comparison of three subbandage pressure measuring devices

Objective: To compare the consistency of the pressure measurements and the practical aspects of three manometers (Salzman MST; Oxford Talley and Diastron) measuring sub-bandage pressures. Methods: Five bandages (tubular elastic straight, tubular elastic graduated, short stretch non-elastic, long stretch elastic, cohesive elastic) were applied to standard models comprising foam-covered 9.5 cm, 12.5 cm diameter plastic tubes and a cone by a single expert bandager using a standard spiral technique with 50% overlap for the non-tubular bandages (NTB). The probes of all three machines were positioned at equidistant points around the circumference of each model at three levels corresponding to the ankle, gaiter and mid-calf measuring points of the MST probe. Two readings were taken for each of three separate applications of each bandage. Statistical analysis utilised ANOVA with Bartlett's test. Results. A total of 135 readings were made for each machine and 81 for each type of bandage. Mean pressures among the five bandages types ranged from 12.2 to 35.5 mmHg. A pressure gradient was apparent when NTB bandaging the straight tubes (means 24.7, 23.5, 22.4 mmHg) but not with the cone. There was a statistically significant difference between the three machines (Bartlett's test 23.6, p<0.0001), with the lowest variances for the MST and similar variances for the Oxford and Diastron. Conclusion. In terms of measurement variance this experiment indicates that the MST is the preferred machine for future experiments.

Evaluation of Compression Therapy: Comparison of Three Sub-bandage Pressure Measuring Devices

Objective: To compare the consistency of the pressure measurements and the practical aspects of three manometers (Salzman MST; Oxford Talley and Diastron) measuring sub-bandage pressures. Methods: Five bandages (tubular elastic straight, tubular elastic graduated, short stretch non-elastic, long stretch elastic, cohesive elastic) were applied to standard models comprising foam-covered 9.5 cm, 12.5 cm diameter plastic tubes and a cone by a single expert bandager using a standard spiral technique with 50% overlap for the non-tubular bandages (NTB). The probes of all three machines were positioned at equidistant points around the circumference of each model at three levels corresponding to the ankle, gaiter and mid-calf measuring points of the MST probe. Two readings were taken for each of three separate applications of each bandage. Statistical analysis utilised ANOVA with Bartlett's test. Results. A total of 135 readings were made for each machine and 81 for each type of bandage. Mean pressures among the five bandages types ranged from 12.2 to 35.5 mmHg. A pressure gradient was apparent when NTB bandaging the straight tubes (means 24.7, 23.5, 22.4 mmHg) but not with the cone. There was a statistically significant difference between the three machines (Bartlett's test 23.6, p&lt;0.0001), with the lowest variances for the MST and similar variances for the Oxford and Diastron. Conclusion. In terms of measurement variance this experiment indicates that the MST is the preferred machine for future experiments.

Preoperative Assessment for Carotid Artery Stenosis: Utility of a Combined Diagnostic Approach by Dynamic MRA and CTA

Dynamic Magnetic Resonance Angiography (MRA) and Computed Tomography Angiography (CTA) represent two non-invasive techniques which can perform a pre-therapeutic evaluation of carotid artery disease. Ultrasound (US) is the screening technique for this type of pathology and after US results, surgeons or endovascular therapists need more information for a correct therapeutic approach. We performed a combined diagnostic approach with CTA and dynamic MRA to reduce the need for DSA in which permanent and transitory neurological side effects are still possible and to evaluate the efficacy of these two diagnostic modalities. We performed dynamic MRA and CTA in 80 patients with carotid disease in which a US examination showed the presence of more than 60% stenosis. Dynamic MRA was performed with a 3D coronal volumetric acquistion with a dedicated head-neck coil, 2.5 mm thickness and 18 s acquisition time after contrast media injection to obtain only the visualization of the arterial phase from the origin of the epiaortic vessels through the bifurcation of the siphon without overlap with the venous phase. CTA was done with a spiral technique with contrast media injection (120 ml- 3ml/s) from C6 through the skull base. In 60 patients, we found the same degree of stenosis between carotid CTA and US examination. In eight cases, US showed an occlusion of the internal carotid artery (ICA) while CTA reported severe stenosis between 85–90%. Two cases showed a 85% stenosis of the ICA, while CTA and dynamic MRA disclosed ICA occlusion. CTA showed parietal thrombus and arterial wall calcifications very well. Dynamic MRA overestimated the stenosis in 85% of the patients, almost always in patients with a stenosis greater than 65–70% and in seven cases also showed an abnormal signal intensity of the origin of the epiaortic vessels or of the intracavernous segment of the ICA that was confirmed by DSA only in four patients. With three patients, it was not possible to perform CTA or MRA because of incorrect transit time evaluation or poor patient cooperation. The combined diagnostic approach by CTA and Dynamic MRA can be adequate to give a correct pre-therapeutic evaluation in patients with carotid disease; in doubtful or uncooperative cases, DSA is still required.

Pixel Bar Charts: A Visualization Technique for Very Large Multi-Attribute Data Sets

Simple presentation graphics are intuitive and easy-to-use, but show only highly aggregated data presenting only a very small number of data values (as in the case of bar charts) and may have a high degree of overlap occluding a significant portion of the data values (as in the case of the x-y plots). In this article, the authors therefore propose a generalization of traditional bar charts and x-y plots, which allows the visualization of large amounts of data. The basic idea is to use the pixels within the bars to present detailed information of the data records. The so-called pixel bar charts retain the intuitiveness of traditional bar charts while allowing very large data sets to be visualized in an effective way. It is shown that, for an effective pixel placement, a complex optimization problem has to be solved. The authors then present an algorithm which efficiently solves the problem. The application to a number of real-world e-commerce data sets shows the wide applicability and usefulness of this new idea, and a comparison to other well-known visualization techniques (parallel coordinates and spiral techniques) shows a number of clear advantages.

Pixel bar charts: a visualization technique for very large multi-attribute data sets

Simple presentation graphics are intuitive and easy-to-use, but show only highly aggregated data presenting only a very small number of data values (as in the case of bar charts) and may have a high degree of overlap occluding a significant portion of the data values (as in the case of the x-y plots). In this article, the authors therefore propose a generalization of traditional bar charts and x-y plots, which allows the visualization of large amounts of data. The basic idea is to use the pixels within the bars to present detailed information of the data records. The so-called pixel bar charts retain the intuitiveness of traditional bar charts while allowing very large data sets to be visualized in an effective way. It is shown that, for an effective pixel placement, a complex optimization problem has to be solved. The authors then present an algorithm which efficiently solves the problem. The application to a number of real-world e-commerce data sets shows the wide applicability and usefulness of this new idea, and a comparison to other well-known visualization techniques (parallel coordinates and spiral techniques) shows a number of clear advantages.

Dose reduction in CT examination of children by an attenuation-based on-line modulation of tube current (CARE Dose).

In a controlled patient study we investigated the potential of attenuation-based on-line modulation of the tube current to reduce milliampere values (mAs) in CT examinations of children without loss of image quality. mAs can be reduced for non-circular patient cross sections without an increase in noise if tube current is reduced at those angular positions where the patient diameter and, consequently, attenuation are small. We investigated a technical approach with an attenuation-based on-line control for the tube current realised as a work-in-progress implementation. The CT projection data are analysed in real time to determine optimal mAs values for each projection angle. We evaluated mAs reduction for 100 spiral CT examinations with attenuation-based on-line modulation of the tube current in a group of children. Two radiologists evaluated image quality by visual interpretation in consensus. We compared the mAs values read from the CT scanner with preset mAs of a standard protocol. Four different scan regions were examined in spiral technique (neck, thorax, abdomen, thorax and abdomen). We found the mAs product to be reduced typically by 10-60% depending on patient geometry and anatomical regions. The mean reduction was 22.3% (neck 20%, thorax 23%, abdomen 23%, thorax and abdomen 22%). In general, no deterioration of image quality was observed. There was no correlation between the age and the mean mAs reduction in the different anatomical regions. By classifying the children respectively to their weight, there is a positive trend between increasing weight and mAs reduction. We conclude that mAs in spiral CT examinations of children can be reduced substantially by attenuation-based on-line modulation of the tube current without deterioration of image quality. Attenuation-based on-line modulation of tube current is efficient and practical for reducing dose exposure to children.

Moving to the routine management of pre symptomatic lung cancer

Lung cancer is the world's leading cause of cancer death. Since progress in the treatment of this cancer has been exceedingly slow, the upswing in tobacco consumption in many sectors becomes even more tragic. One area for cautious optimism is the recent pilot reports of improved early lung cancer detection using new spiral CT techniques from institutions in Japan and New York. The prospect of improved early detection in a major cancer raises a number of public health concerns and highlights the importance of critical validation of this proposed new tool. From experience with early detection-based management of other cancers, it is evident that the entire process of detection, case validation, intervention, monitoring and public education needs to be carefully developed. The International Association for the Study of Lung Cancer has worked with the National Cancer Institute over the last decade to nurture interest and expertise in conducting population-based management of early lung cancer. A distillation of this process up to the current time is reviewed in this manuscript.

Low nutrient medium and spiral-plate system for enumerating heterotrophic bacteria in soil

Identifying appropriate media to quickly and accurately enumerate bacteria in soil has been a continuing problem in microbiology research. Our objective was to determine the accuracy of the spiral plating technique to assess bacteria population in soil samples and its compatibility with low and high nutrient media. Colony numbers and the area covered by spreading organisms at 48, 72, and 144 hr were compared among four culture media (Standard Methods Agar [SMA] at 1%, 10%, and 100% strength, and Modified Egg Albumen Agar [MAA]) using two contrasting soils. The correlation between the spiral and the spread plating methods on MAA was tested using 17 soil samples. MAA gave the same or higher colony counts compared to full strength or diluted SMA. Colony size was larger on MAA than on 1% or 10% SMA. Confluent colonies that overgrew diluted and full strength SMA plates were largely absent from MAA plates. There were no differences between colony counts from spiral plating and spread plating methods using MAA. Colony numbers (log CFU g−1 dry soil) from both methods on several soils were strongly related (R2=0.97, n= 17, p<0.01) and followed the relationship y= 1.008x - 0.125 where y represents the spread plate method and x the spiral plate method. Use of MAA media with the spiral plating technique provides automation of bacteria enumeration without sacrificing either numerical counts or the appearance of discrete colonies.

Computed Tomography: Fundamentals, System Technology, Image quality and Applications

W A Kalender Munich: Publicis MCD (2000) 220pp, price: �32.50, ISBN: 3-8957-8081-2 This book is a very well-written overview of CT by an imaging scientist who has made many significant contributions to this field over the past sixteen years. With the recent renewed interest in CT based on the widespread adoption of multi-slice spiral scanners, this text is a timely publication. The book begins with a preface in the form of an historical overview, and continues with a description of the basic principles of CT image reconstruction and display, as well as some of the necessary underlying physics. The various historical and contemporary scanner designs are described, along with some of the more novel approaches to CT that have appeared over the years. The non-mathematically inclined will appreciate the intuitive style used throughout the book. However, for those who feel short-changed by this approach, an appendix briefly presents some of the mathematical formalism! Befitting the author's own interests, spiral CT receives a thorough treatment. There is an extensive discussion of the similarities and differences between sequentially acquired CT images and those acquired with single and multi-slice spiral techniques, both with respect to the image-reconstruction process and image quality. The discussion of `conventional' and `spiral-specific' artefacts is particularly useful. It is pleasing to see in this book an excellent discussion of patient dose, including measurement and dose-reduction techniques. There are useful tables that quickly allow the operator to gauge the effect on patient dose of various scanning parameters. This chapter is especially valuable for the guidance it provides in determining appropriate scan technique specifications to those prescribing patient examination. The discussion puts diagnostic radiation dose levels in their proper perspective, with the author endorsing the view that the BERT (background equivalent radiation time) be adopted as a way of meaningfully expressing diagnostic exposure with respect to background. In view of the fact that modern CT scanners generate huge amounts of data, the section on image processing and display is timely. The author discusses the various means of visualizing 3D images, and discusses the rationale for using one method over another. The book concludes with a brief discussion of special applications and a look to the future of CT. The applications and limitations of CT to provide quantitative information are highlighted, and the exciting new field of dynamic cardiac CT is briefly discussed. The book is well illustrated and can be read by a wide audience. The volume by itself is a superb resource. An added bonus is the CD-ROM that comes with it. In addition to its high-resolution figures and the additional clinical examples it provides, this disk contains animations of the reconstruction process, and a fully functional image browser to allow the reader to manipulate several example 3D CT datasets. I highly recommend this book to both the radiological and the imaging physics communities. It provides a superb overview of the contemporary state-of-the-art of CT, and is an excellent resource for those involved in teaching medical imaging to scientists or physicians.

CT bronchus sign in malignant solitary pulmonary lesions: value in the prediction of cell type.

The aim of this study was to evaluate differences in the prevalence of patterns of CT bronchus sign in malignant solitary pulmonary lesions (SPLs), according to their histologic cell types and with respect to size, location, and degree of cell differentiation. Computed tomography scans of 78 patients, in whom pathologically confirmed malignant SPLs with CT bronchus sign were present, were randomly selected and reviewed by two radiologists under consensus. All 78 were CT scans done using spiral technique with 10-mm collimation and 10-mm reconstruction intervals with enhancement, and 75 included additional high-resolution CT scans. Lesions were classified into four cell types as squamous cell carcinoma (n = 24), small cell carcinoma (n = 12), adenocarcinoma (n = 23), bronchioloalveolar carcinoma (BAC; n = 9), and others (n = 12), into three degrees of differentiation, into three size groups, and according to location (central or peripheral). Patterns of CT bronchus sign were classified into abruptly obstructing (I), patent (II), displacing (III), or tapered narrowing (IV) types. The relationships between the patterns of CT bronchus sign and cell type and degree of cell differentiation were evaluated. Eighty patterns of CT bronchus sign were observed in 78 patients. According to cell type, squamous cell carcinoma showed most often type-I pattern (45.8%) but no type-II pattern, which was the most common pattern observed in BAC (77.8%) and adenocarcinoma (34.8%; p<0.01). Small cell carcinoma showed a varied distribution among the four patterns of CT bronchus sign. According to location, in central squamous cell carcinomas, type-I pattern was more common(55%; p<0.01). Bronchioloalveolar carcinoma showed more peripheral lesions and in both central and peripheral lesions, type-II pattern was significantly more common (100 and 66.7%; p<0.01). In SPLs with CT bronchus sign of obstructing pattern, especially if central location, squamous cell carcinoma should be suspected, whereas in SPLs with patent CT bronchus sign, regardless of the location, the strong possibility of BAC should be considered.