bluuebunny/crossref_metadata_2025 huggingface dataset:
Columnar to Equiaxed Transition in Peritectic TiAl Based Alloy Studied by a Power-Down Technique
Authors: Lapin Juraj , Gabalcová Zuzana , Hecht Ulrike , Mooney Robin Patrick , Mcfadden Shaun
Published: May 2014

Columnar to equiaxed transition (CET) was studied in a peritectic TiAl-based alloy with chemical composition Ti-45.1Al-4.9Nb-0.25C-0.2B (at.%). Solidification experiments were conducted in a Bridgman-type apparatus using cylindrical moulds made of high-purity Y2O3. The methodology containing appropriate etching and observations under flat light in stereo-microscope was used to identify the morphology of primary β phase grains and position of CET in the samples˰ All samples prepared by power down-technique showed sharp CET. The position of the CET measured from the beginning of the sample depends on the applied cooling rate and increases from approximately 65 to 115 mm by decreasing cooling rate from 50 to 15 K/min. Based on terrestrial experiments, the future work focused on microgravity and hypergravity CET experiments and numerical modeling is proposed. A Bridgman furnace front tracking method will be applied in future work to complement the experimental results here as part of the European Space Agency GRADECET programme. This modeling will input directly into planned microgravity and hypergravity CET experiments.
Design and Microstructure of Innovative Cobalt Base Alloy
Authors: Peter Ildiko , Rosso Mario , Ioan Dan , Ghiban Brandusa , Castella Christian
Published: May 2014

Design and characterization of modified Cobalt base alloy for biological applications have been studied and compared. In particular, modification has been realized by addition of Mo, Ti and Zr to better fit the requirements for dental applications. On the samples morphological and surface analysis including residual stress determination have been considered. As a result of this study, a positive effect of Ti addition has been demonstrated. Contrarily, a simultaneous addition of Ti and Zr does not promote any enhancement as microstructure and properties concern.
Investigating the Foamability Decrease of Water-SiO2 Suspension
Authors: Somosvári Béla M. , Bárczy Pál
Published: May 2014

Shelf-lives of surfactant containing water SiO2 suspensions were investigated by observing the loss of foamability with time and by making various measurements on the compounds used. Main purposes were to discover the reason of the strong foamability decrease with time and to separate the gravity driven effects. These questions arose in the frame of FOCUS - Foam Casting and Utilisation in Space microgravity experiment preparations (ID: SURE AO-019/PECS 98045, EC contract no: RITA-CT-2006-026069). Foams were prepared using special foaming cartridges, by gas introduction after loading the suspension into the porous structure of the foam generator (FG). Freshly infiltrated FG-s showed superior foamabilities, but this feature was lost after a few days of storage. Several possible chemical or physical reasons were investigated experimentally, including the direction of storage position, composition change, storage temperature, etc. Investigation of gravity-driven sedimentation and creaming tendencies were also examined using dynamic light scattering (DLS) method. These effects found to have significant impact on foamability.
Liquidus and Solidus Temperature Calculation in Al-Cu-Fe System by ESTPHAD Method
Authors: Mende Tamás , Tatárka Eszter , Kőrösy Gergely , Roósz András
Published: May 2014

In this paper, the thermodynamic basis of ESTPHAD method is briefly shown and the development of the whole ternary calculation can be followed: the first step is the calculation of liquidus and solidus temperatures of the binary phase diagrams (Al-Cu and Al-Fe), the second step is the estimation of the liquidus and solidus surfaces (Al-Cu-Fe system), and the last step is the calculation of liquidus and solidus slopes by using the derivative function of the calculated ESTPHAD equations.
Studying Pressure Induced Whiskers Formation from Sn-Rich Surfaces
Authors: Sycheva Anna , Radanyi Adam , Gácsi Zoltán
Published: May 2014

Whiskers formed on the lead-free tin surfaces pose a serious risk to small electronic devices causing a short circuit and leading to the component/device failure. The present research was focused on the investigation of tin whisker formation on a motor control unit sockets made of tin coated copper, applying to the specimen mechanical load alone or together with heat treatment/electric current. Scanning Electron Microscopic (SEM) imaging was applied in order to study the microstructure of tin whiskers obtained, their length and number at the boundary of each imprint. If the mechanical stress increases from 1000 to 5000 MPa, the average number of whiskers and possible formation spots also increase from 570 to 1300. The length of whiskers varied from 3 μm after 0.5 h to 5.5 μm after 3 hours of exposition. It has been found that heat treatment at 150°C for 1 hour significantly reduces the number of whiskers (on average 6 times as few) formed. Therefore, the threat of failure of the electronic equipment is reduced.
On the Relationship between Inclusions and Pores, Part II: Dendritic Structure, Pressure Drop in the Liquid and Pore Precipitation
Authors: Nick Arash Safavi , Fredriksson Hasse
Published: May 2014

There is a relationship between pores and inclusions. As hypothesis goes, inclusions have an affinity to gather inside the pores and form clusters. Focus of this paper is how solidified dendritic structure affects the pressure field in the liquid and pore precipitation in austenitic stainless steel. Steel sample is a continuously cast bloom. Temperature profile and width of the mushy zone of the strand is modeled according to a constant temperature at the strands surface. Thermal analysis has been performed with differential thermal analysis (DTA) and differential scanning calorimeter (DSC). Dendrite arm spacing (DAS) is measured with light optical microscopy (LOM) and scanning electron microscopy (SEM). DAS is represented as the weight average of the distance between parallel sets of primary dendrite stems. Pressure field is calculated based on Darcys law. Pore formation is described through segregation of the gas components and pressure field in the liquid.
Determination of the Origin of Anomalous Eutectic Structures from In Situ Observation of Recalescence Behaviour
Authors: Mullis Andrew M. , Clopet Caroline R. , Cochrane Robert F.
Published: May 2014

A melt encasement (fluxing) method has been used to undercool Ag-Cu alloy at its eutectic composition. The recalescence of the undercooled alloy has been filmed at high frame rate. At low undercooling lamellar eutectic is observed to grow, giving way to a mixed anomalous-lamellar structure at higher undercooling. In situ observation of the spot brightness reveals, as expected, that the lamellar eutectic grows via a planar front mechanism, while the anomalous eutectic grows via a more complex process characterised by a double recalescence. The first recalescence is non-space-filling (dendritic) in character and is followed shortly afterwards by a second recalescence which appears to be of the planar front type. Moreover, the first recalescence event appears to be to a temperature in excess of the equilibrium eutectic temperature. This is strongly suggestive that the anomalous eutectic morphology arises due to the growth and subsequent partial remelting of a dendritic morphology, probably a two-phase (eutectic) dendrite, followed by planar front growth of a lamellar eutectic into the residual liquid.
The Effect of Sulfur on the Contact Angle between Liquid Eutectic Fe-V-C Alloy and VC Substrate and on the Microstructure of the Alloy
Authors: Boccalini Júnior Mário , de Oliveira Corrêa Alzira Vicente
Published: May 2014

The sessile drop technique was used to evaluate the contact angle between liquid eutectic Fe-11wt%V-2.3wt%C alloy and VC substrate. This alloy solidifies through a eutectic reaction that starts at 1320°C and leads to the formation of the faceted/non-faceted austenite-VC eutectic. The effect of sulfur on the contact angle and on morphology of the austenite-VC eutectic in both non-directionally and unidirectionally solidified specimens was investigated. It was shown that sulfur increases the contact angle and modifies the eutectic morphology, thus indicating a relationship between eutectic morphology and liquid eutectic/faceted phase VC interfacial energy.
Magnetic Fields, Convection and Solidification
Authors: Hachani Lakhdar , Wang Jiang , Kaldre Imants , Salloum-Abou-Jaoude Georges , Budenkova Olga , Reinhart Guillaume , Zaidat Kader , Mangelinck Nathalie , Li Xi , Nguyen Thi Henri , Bojarevics Andris , Ren Zhong Ming , Buligins Leonids , Fautrelle Yves
Published: May 2014

In solidification processes the fluid flow occurs almost at every scale from the bulk, near the interfaces and deeply in the mushy zone. Numerical modeling is a valuable tool for understanding and master the solidification processes, however, macro-scale models are not always able to predict in detail the random behavior of the solidification process whereas models for micro scales are not capable to take into account a complex structure of flows which enter into the mushy zone. In the present paper the variety of the flows and imprints they left on solidification structure are discussed and illustrated with experimental data which naturally comprise every flow occurring in the process.
Influence of Crystal Morphological Parameters on the Solidification of ESR Ingot
Authors: Karimi-Sibaki Ebrahim , Kharicha Abdellah , Korp J. , Wu Meng Huai , Ludwig Andreas
Published: May 2014

Electroslag remelting (ESR) is an advanced process to produce high quality steel. During the ESR process, the steel electrode is melted and then solidified directionally in a water-cooled mold. The quality of the ingot is strongly dependent on the shape of melt pool, i.e. the depth and thickness of mushy zone, which is in turn influenced by the bulk and interdendritic flow. Here, we perform a numerical study to investigate the effect of crystal morphological parameter such as primary dendrite arm spacing on the solidification of the ESR ingot ( 750 mm). The crystal morphology is dominantly columnar and dendritic, thus a mixture enthalpy-based solidification model is used. Accordingly the mushy zone is considered as a porous media where the interdendritic flow is calculated based on the permeability. The permeability is determined as function of the liquid fraction and primary dendrite arm spacing according to Heinrich and Poirier [Comptes Rendus Mecanique, 2004, pp. 429-44]. The modeling results were verified against experimental results.
Numerical Simulation of the RMF Stirring of Molten Ga-In Alloy Using RANS K-ε and LES Turbulence Models
Authors: Nagy Csaba , Fautrelle Yves , Budenkova Olga , Rónaföldi Arnold , Roósz András
Published: May 2014

A comparison of the results of RANS k-ε and LES turbulence models was done via the simulation of the electromagnetic stirring of liquid 75,5%Ga-24,5%In alloy (in a 10 mm diameter & 30 mm high crucible) using Ansys Fluent. Each velocity component, the distribution of eddies inside the melt and other flow parameters were compared respectively. The accuracy was checked with measured angular velocity data of A. Rónaföldi. The turbulent energy spectra were also produced to see the validity of the LES models.
The Effect of Inoculation on the Thermal Expansion/Contraction during Solidification of Gray Cast Iron
Authors: Tadesse Abel , Fredriksson Hasse
Published: May 2014

Inoculation of casting used to improve the microstructure and the properties of the component. Depending upon the area of application, gray cast iron has different microstructure and mechanical properties. The type and amount of the inoculation result in shape and orientation differences of the flake graphite. The Linear Variable Differential Transformer (LVDT) shows a variation in displacements change during the solidification. Temperature measurement used to analyze cooling curves and microstructural analysis of sample to examine the physical differences. Thermal analysis compared with the experimental results and microstructural study for describing the variation in area fraction and shape of graphite. The experimental result indicates contraction in austenite formation region, and expansion in eutectic formation region. The effect of the inoculant and the superheat temperature shows a variation in degree of expansion/contraction and cooling rates of the experiments. The comparisons between the experimental and the theoretical results have been done. Combining the theoretical and experimental results, it resembles a difference in eutectic formation region, and it needs carful investigation in future works.
Designing Amorphous/Crystalline Composites by Liquid-Liquid Phase Separation
Authors: Janovszky Dóra , Tomolya Kinga
Published: May 2014

The Cu-Zr-Ag system is characterized by a miscibility gap. The liquid separates into Ag-rich and Cu-Zr rich liquids. Yttrium was added to the Cu-Zr-Ag and Cu-Zr-Ag-Al systems and its influence on liquid immiscibility was studied. This alloying element has been chosen to check the effect of the heat of mixing between silver and the given element. In the case of Ag-Y system it is highly negative (-29 kJ/mol). The liquid becomes immiscible in the Cu-Zr-Ag-Y system. To the effect of Y addition the quaternary liquid decomposed into Ag-Y rich and Cu-Zr rich liquids. The Y addition increased the field of miscibility gap. An amorphous/crystalline composite with 6 mm thickness has been successfully produced by liquid-liquid separation based on preliminary calculation of its composition. The matrix was Cu38Zr48Al6Ag8 and the crystalline phases were Ag-Y rich separate spherical droplets.
Formation of the Surface Layer with Improved Tribological Properties on Austenitic Stainless Steel by Alloying with REE Using HIPPB
Authors: Sartowska Bożena , Barlak Marek , Waliś Lech , Senatorski Jan , Starosta Wojciech
Published: May 2014

Austenitic stainless steels with their very good corrosion resistance are used in industrial applications nuclear and petrochemical industries, pulp and paper chemical, food and chemical processing, biomedical industries and others. But poor tribological and mechanical properties of austenitic stainless steels limit their applications in engineering fields. AISI 316L steel was subjected to transient treatment using high intensity pulsed plasma beams HIPPB. The plasma pulses contained both ions/atoms of electrodes material: Ce, La or (Ce+La) and those of working gas. The pulse energy densities (3.0 J/cm2) were sufficient to melt the near surface layer of steel and introduce REE to the melted material. Heating and cooling processes were of non-equilibrium type.
Concentration Dependent Growth Velocities in Undercooled Al-Rich Al-Ni Alloy Systems
Authors: Ehlen Georg J. , Wang Hai Feng , Herlach Dieter M.
Published: May 2014

Dendrite growth velocity V as a function of undercooling on the Al-rich side of the Al-Ni system has recently been measured by electromagnetic levitation. The results have shown an anomalous behaviour, which so far cannot be theoretically described. The present work uses two simplified qualitative models of sharp interface theory, one of them treating the forming AlNi (B2) phase as a solid-solution, one treating it as an intermetallic phase, to investigate the influence of the phase diagram on the growth velocities. The results imply that the concentration dependent growth behaviour is a superposition of at least two effects: 1) A strong decrease of the total growth velocitiy level for increasing Al concentrations. 2) An increase of growth velocities with increase of Al concentration at medium and low undercoolings. The present work is able to explain the first effect, namely the concentration dependent reduction of velocities. Results are compared to experimental data. In both models the properties of the phase diagram lead to an increase of the constitutional undercooling ΔTc when the Al content increases. This reduces the fraction left for kinetic undercooling ΔTk, which is responsible for interface migration and which determines the growth velocity. Neither of the models can reproduce the second effect.
A Numerical Study of the Influence of Pouring Technique on the As-Cast Structure of Al-Cu Ingots
Authors: Ahmadein Mahmoud , Wu Meng Huai , Schumacher Peter , Ludwig Andreas
Published: May 2014

Experimental evidence [Ohno 1987] revealed the influence of some pouring techniques on the as-cast structure. In the current work the process of pouring of the molten Al-4.0 wt.%Cu via one or multiple streams into a graphite mold is studied using a 3-phase model by considering the nucleation, the initial growth and transport of globular equiaxed crystals. The three phases are the melt, air and globular equiaxed crystals. Results showed that pouring via multiple streams increases the volume fraction and number density of crystals in the as-filled state. The subsequent solidification is calculated using a 5-phase mixed columnar-equiaxed solidification model. The five phases are the extradendritic melt, the solid dendrite and interdendritic melt inside the equiaxed grains, the solid dendrite and interdendritic melt inside the columnar grains. As final result the as-cast structure including the distinct columnar and equiaxed zones, columnar-to-equiaxed transition (CET), grain size, macrosegregation, and rest eutectic is predicted. Effect of melt convection and crystal sedimentation during the pouring and solidification is taken into account. The predicted as-cast structure, under the influence of single/multiple jet pouring, is evaluated bycomparison with the available experiments of Ohno.
3D Meso-Scale Modeling of Solidification for Aluminum-Alloy Welding
Authors: Zareie Rajani Hamid Reza , Phillion Andre Bernard
Published: May 2014

Meso-scale modeling through the use of a granular-type model is a key new tool for predicting solidification-related defects. In the present study, the application of a granular-type model to welding microstructure is presented, along with application challenges and solutions. This new model can simulate the solidification of a weld pool at the mesoscale, i.e. both solid grains and liquid are included. Consequently, the behaviour of the semisolid structure within the weld pool can be studied. By means of this 3D meso-scale model, the continuous network of liquid channels that forms at the last stages of solidification have been investigated, allowing for prediction of the variation in the distribution of liquid channel width as a function of welding parameters.
Indicator mineral abundance data for a bedrock sample from the Little River antimony occurrence, Newfoundland and Labrador
Authors: McClenaghan M B , Averill S A
Published: May 2014

As part of the Geological Survey of Canada's Targeted Geoscience Initiative 4 (TGI-4) Program, one bedrock sample was collected from the Little River antimony occurrence in southern Newfoundland to determine the indicator minerals that are indicative of Sb
deposits. The purpose of this open file is to report the raw indicator mineral weight and abundance data for the bedrock sample collected in 2012 for this case study. The sample was processed using a combination of tabling, panning, and heavy liquids to recover potential indicator minerals. Sample
location, weights of various fractions produced during sample processing, and indicator mineral grains identified are reported in this open file. Two Sb minerals were recovered from the bedrock sample, stibnite and stibiconite, as well as gold, arsenopyrite, and pyrite. This study provides
preliminary insights into the physical appearance, size, and abundance of Sb-rich minerals which will help in the future identification of Sb-rich indicator minerals in unconsolidated surficial sediments.
Establishing student perceptions of an entrepreneur using word associations
Authors: Goliath Jasmine E. , Farrington Shelley M. , Saunders Shelley B.
Published: May 2014

Orientation: To understand entrepreneurial behaviour, it is important to understand the image or perceptions associated with entrepreneurship.Research purpose: To identify the image or perceptions that students have of an entrepreneur.Motivation for study: By establishing the image or perceptions that students have of an entrepreneur, insights could be provided into the factors influencing them to become entrepreneurs or not.Research approach, design and method: A qualitative projective technique, namely continuous word association, was adopted. Convenience sampling was used and 163 students participated. The words generated were coded into categories by searching for themes and words of a similar nature. The total words generated, the frequencies of recurring words, the number of different types of words, first words recalled and the average number of words recalled were established.Main findings: The students participating in the study have a good understanding of the general nature of an entrepreneur and entrepreneurship; an entrepreneur is perceived as someone who is a creative and innovative risk-taker, who owns a business involved in the selling of goods and services.Practical/managerial implications: Future entrepreneurs need to be aware that, in addition to several innate attributes, successful entrepreneurs have learned skills and competencies. It is also important that educators of entrepreneurship create a realistic image of what it is like to be an entrepreneur, and that both positive and negative aspects are highlighted.Contribution/value-add: By identifying the image or perceptions of an entrepreneur held by students, the marketing of entrepreneurship as a desirable career choice can be enhanced.
Assessing Cervical Stability: A Reminder
Authors: Emby Donald Jan , Lancaster Andrew Harold Swinburne
Published: May 2014

No abstract available.
Computed Radiography Exposure Indices in Mammography
Authors: Koen Liebner , Herbst Charles , Rae William
Published: May 2014

Studies indicate that computed radiography (CR) can lead to increased radiation dose to patients. It is therefore important to relate the exposure indicators provided by CR manufacturers to the radiation dose delivered so as to assess the radiation dose delivered to patients directly from the exposure indicators. The aim of this study was to investigate the performance of an Agfa CR system in order to characterize the dose indicators provided by the system. The imaging plate response was characterized in terms of entrance exposure to the plate and the digital signal indicators generated by the system (SAL - Scanning Average Level and lgM - Logarithmic median) for different beam qualities. Several exposures were performed on a mammography unit and the digital signal, expressed as SAL and lgM for each image was correlated with the entrance exposure on a standard ACR phantom. From this, the relationship between the Agfa dose indices (SAL and lgM) and the average glandular dose (AGD) in mammography was established. An equation was derived to calculate the AGD delivered to the patient as a function of the exposure indicator, lgM, and the kV. The results indicated that the measured AGD at 28kV for a standard breast thickness during routine calibration with the ACR phantom was 1.58mGy (lgM = 1.99), which is within 1.5% of the value calculated using the derived equation for a standard Perspex thickness of 4.2cm using the AEC (1.56mGy). The standard error in using this equation was calculated to be 8.3%.
Imaging findings of meconiuim peritonitis
Authors: Naidoo L
Published: May 2014

No abstrac available.
Is MRI as safe as we think?
Authors: Wahab S , Khan R A , Ullah E , Wahab A
Published: May 2014

Magnetic resonance imaging (MRI) is nowadays widely used as a noninvasive imaging modality for a wide variety of diseases and disorders. A patient placed in the MR system for scanning remains under the influence of powerful static magnetic field, rapidly varying gradient magnetic field and radiofrequency field in addition to the risk factors associated with gadolinium based MR contrast agents. At present, there is no conclusive evidence for adverse biological effects in patients undergoing MRI. However, a clear understanding of the various bioeffects associated with MRI diagnostics is necessary in order to ensure the safety of the patient as well as to justify its clinical use.
Academic news, awards, congresses, workshops
Authors: Andronikou Savvas
Published: May 2014

No abstract available.
PET/CT in South Africa: a lost cause
Authors: Ellmann Annare
Published: May 2014

No abstact available.
Ultrasound - first imaging modality in the detection of parathyroid adenomas
Authors: Ahmed R , Khan N , Ellemdin S , Gayaparsad K
Published: May 2014

Abstract We present a series of 12 patients in whom the typical ultrasound features of parathyroid adenomas were accurately demonstrated. High resolution ultrasound [in experienced hands] is a highly sensitive accurate, safe and non invasive method of localizing parathyroid adenomas especially in patients with typically located glands and an absence of thyroid pathology. Our aim was to compare ultrasound with nuclear medicine as an imaging gold standard in patients with thyroid adenomas.
Unusual mammography findings of patients with ductal carcinoma in situ (DCIS) of the breast.
Authors: Ismail F , Holl J , Lockhat Z , Akande H
Published: May 2014

Abstract The early detection of carcinoma is the highlight of mammography. We present two patients with pathological diagnosis of DCIS with unusual mammographic findings for which one needs to have a higher index of suspicion. The first patient presented with multifocal disease requiring biopsy of all visible lesions and the second patient (twenty four years old) presented with segmental distribution of calcifications, which may have been missed had a single-view baseline mammogram not been done.
The role of the expert witness in court
Authors: Knobel G J
Published: May 2014

No abstact
Endovascular treatment of vein of Galen aneurysmal malformation
Authors: Du Toit J , Bam J A , Mngomezulu V
Published: May 2014

No abstact
Why and wherefore the RSSA?
Authors: Sperryn C
Published: May 2014

No abstact
Cover
Authors: Griffin Clinton M
Published: May 2014

N/A
Contents
Authors: Griffin Clinton M
Published: May 2014

N/A
Mammographic CAD: Correlation of regions in ipsilateral views - a pilot study
Authors: Padayachee J , Alport M J , Rae W ID
Published: May 2014

Background: Radiologists analyse both standard mammographic views of a breast to confirm the presence of abnormalities and reduce false-positives. However, at present no computer-aided diagnosis system uses ipsilateral mammograms to confirm the presence of suspicious features.

Aim: The aim of this study was to develop image-processing algorithms that can be used to match a suspicious feature from one mammographic view to the same feature in another mammographic view of the same breast. This algorithm can be incorporated into a computer-aided diagnosis package to confirm the presence of suspicious features.

Method: The algorithms were applied to 68 matched pairs of cranio-caudal and mediolateral-oblique mammograms. The results of this pilot study take the form of maps of similarity. A novel method of evaluating the similarity maps is presented, using the area under the receiver operating characteristic curve (AUC) and the contrast (C) between the area of the matched region and the background of the similarity map.

Results and Conclusions: The first matching algorithm (using texture measures extracted from a grey-level co-occurrence matrix (GLCM) and a Euclidean distance similarity metric) achieved an average AUC=0.80±0.17 with an average C=0.46±0.26. The second algorithm (using GLCMs and a mutual information similarity metric) achieved an average AUC=0.77±0.25 with an average C=0.50±0.42. The latter algorithm also performed remarkably well with the matching of malignant masses and achieved an average AUC=0.96±0.05 with an average C=0.90±0.21.
Mammographic normal variant : the sternalis muscle
Authors: Meerkotter D
Published: May 2014

The imaging findings of a normal variant seen on mammography are presented in this article. The sternalis muscle is an uncommon normal variant, seen only in 8% of cadaveric studies. It is increasingly demonstrated with mammography as imaging techniques improve. This normal variant needs to be differentiated from significant pathology and can pose a diagnostic dilemma. In this article the anatomy of this muscle and the imaging findings are discussed. In selected cases computed tomography (CT) or magnetic resonance imaging (MRI) will be required to investigate the mammographic findings further and these modalities are described regarding the assessment of the sternalis muscle.
CPD Questions
Authors: Fani Gertrude
Published: May 2014

CPD Questionnaire
Cranial MRI diagnosis
Authors: Misser S K
Published: May 2014

N/A
Radiation free-for-all is imminent
Authors: Lotz Jan
Published: May 2014

N/A
Large uncomplicated hydropneumopericardium
Authors: Rakotoarivelo R A , Razafimahefa S H , Ramanalimanana P , Ranoharison D , Johnson A D , Rakotoarimanana S
Published: May 2014

N/A
Straight talking on CT scanning
Authors: Tipler Bradley M
Published: May 2014

N/A
Is airway diameter measured accurately on routine axial CT scans? Comparison with true axial diameter using MPR in children with airway compression owing to pulmonary TB
Authors: Grobbelaar Marie , Andronikou Savvas
Published: May 2014

Airway compression is a common complication of TB lymphadenopathy in children, and the diagnostic workup of patients with suspected tracheal or bronchial stenoses includes bronchoscopy and CT (computed tomography).2 This process affords the opportunity to study aspects of CT relating to airway stenosis. Axial CT scans produce excellent resolution in the horizontal plane, but the extent of airway disease may be underestimated if only axial images are obtained.

An advantage of using multidetector CT (MDCT) is the use of multiplanar reconstruction (MPR) to align the image along the longitudinal axis of the airway. There is also uncertainty if window settings affect the measurement of the airway diameter.

We wished to determine if there was a significant difference between the measurements of compressed airway diameter in the axial plane compared with measurements of diameter using MPR for determining longitudinal axis of the airway; and to evaluate how measurements on lung window settings compare with soft tissue window settings.
Use of MR sialography and T2W fat-suppressed series in parotitis
Authors: Pretorius Phil
Published: May 2014

Imaging can be helpful when investigating salivary gland pain and swelling. Typically in such cases, an ultrasound (US) or conventional sialogram would be requested in seeking obstructed or dilated ducts, a ductal calculus or an abscess within the gland. Occasionally a CT scan is requested. MR is usually reserved for investigating clinically palpable masses in the glands.

In acute non-obstructive parotitis, the differential diagnosis includes acute non-suppurative parotitis (as found in mumps), early Sjögren’s syndrome, or suppurative parotitis as seen following duct obstruction. Despite sometimes strong insistence on retrograde contrast sialography, this may exacerbate the pre-existing inflammatory process. The imaging of a young patient expands on these observations.
A clarion call to South African Radiology
Authors: Lotz Jan
Published: May 2014

N/A
Uraemic tumoral calcinosis in patients on haemodialysis in the renal unit at Dr George Mukhari Hospital, Pretoria
Authors: Suleman F E , Mngomezulu V , Ebrahim N
Published: May 2014

Objective. Uraemic tumoral calcinosis refers to metastatic calcifications that occur rarely on the extensor surfaces of joints in patients undergoing long-term haemodialysis. The aim of the study was to assess the incidence of uraemic tumoral calcinosis in participants undergoing haemodialysis and to investigate any relationship that might exist between the development of uraemic tumoral calcinosis and the length of time on dialysis.

Design. Twenty-four of the 25 patients on haemodialysis at the time of the study underwent radiographs of their shoulders and hips to look for calcinosis, which were then read by the researcher and two independent readers to assess for calcinosis.

Study setting. Dr George Mukhari Hospital, Pretoria.

Results. Eight per cent (N=2) of participants were found to have asymptomatic calcinosis of the hips. No relationship to length of time on dialysis was found.

Conclusions. The study was constrained by a small sample size but the presence of calcinosis in 8% of the participants indicates that an extensive study of a larger sample could prove to be useful in determining the true incidence of uraemic tumoral calcinosis in the region. Long-term follow-up could provide more information on the development of calcinosis and length of time on dialysis.
Acute pituitary apoplexy complicating a pituitary macroadenoma
Authors: Joseph Febin , Lockhat Zarina I , Janse van Rensburg Malan , Smal Janet , Moja Tshepo Peter
Published: May 2014

Pituitary apoplexy is a rare but potentially life-threatening condition caused by either haemorrhage or infarction of the pituitary gland. In most cases, a pre-existing pituitary macroadenoma is present. Patients present with the clinical syndrome of headache, visual defects or ophthalmoplegia, altered state of consciousness and variable endocrine deficits.
Camurati-Engelmann disease
Authors: Bellew Neil , Wagener Georg
Published: May 2014

Camurati-Engelmann disease (CED), or progressive diaphyseal dysplasia, is a rare sclerosing dysplasia of which 250 cases have been described in the English literature. The disease affects one in a million people and is autosomal dominant with variable penetrance. It was initially described by Cockayne in 1920; Camurati was the first to suggest its hereditary nature in 1922. A single case of muscular wasting and marked bone involvement was reported by Engelmann in 1929. As the name suggests, there is progressive hyperostosis and predominant involvement of the diaphyses.

The onset of the disease is usually during childhood; patients usually present by puberty and usually before age 30, with limb pain, muscular weakness, waddling gait and easy fatigue. Other symptoms and signs may include delayed growth, reduced muscle mass, anorexia and enlargement of the arms and legs. Systemic manifestations of hepatosplenomegaly, bone marrow dysfunction (anaemia and leucopaenia) and delayed sexual development occasionally occur. In a few patients, abnormal values of bone resorption and formation have been described.

Radiologically, the hallmark of the disorder is bilateral, symmetrical cortical thickening of the diaphyses of the long bones on both the periosteal and endosteal sides of the diaphyses. In decreasing order of frequency, the tibia, femur, fibula, humerus, ulna and radius are affected. CED results from disturbance of intramembranous ossification (Fig.1) affecting the long bones, calvaria, mandible and facial bones. There are a few reported cases of involvement of the skull base (a site of endochondral ossification), but these occur in advanced stages.
The injured snowman
Authors: Mahomed N , Goodier M , Modi M , Andronikou S
Published: May 2014

Total anomalous pulmonary venous return (TAPVR) is a rare congenital cardiac defect that may present with cyanosis, cardiac failure and failure to thrive in infancy. TAPVR type 1 has a typical radiographic appearance of the heart termed the snowman. We present a case of an infant with TAPVR type 1 with injuries in keeping with non-accidental injury (NAI) to highlight that children with chronic diseases are at greater risk of this kind of injury and that radiographic evaluation of the chest in cardiac disease plays a role beyond demonstrating the heart and vasculature of the chest.
Neurological case: Cognitive decline and depressed level of consciousness in AIDS
Authors: Els Hein , Andronikou Savvas
Published: May 2014

N/A
Irradiating of children: whose responsibility?
Authors: Jamieson Douglas H
Published: May 2014

Irradiating of children: whose responsibility?
Radiological chest manifestations in diffuse infiltrative lymphocytosis syndrome (DILS)
Authors: Ismail F , Van de Werke I , Khan N , Levay P , Davel G
Published: May 2014

This report focuses on the radiological manifestations of diffuse interstitial lymphocytosis syndrome (DILS) in the chest. Awareness of this entity and early diagnosis by radiologists will enable timeous intervention by clinicians.
Delayed post-surgical sepsis from Teflon felt: The diagnostic value of CT scanning, and a reminder for theatre staff
Authors: Emby D , Lancaster A
Published: May 2014

We report on 2 patients with surgical site infections following the inadvertent use of Teflon felt for haemostasis in elective and emergency surgery. CT scanning was superior to plain radiography in demonstrating the foreign bodies to enable planning of further surgical treatment.
MRI imaging of vein of Galen malformations at Steve Biko Academic Hospital: A mini case series
Authors: D Liesel , Smal J , Lockhat Z
Published: May 2014

N/A
Arrythmogenic right ventricular dysplasia/cardiomyopathy
Authors: Scholtz Leonie , Van Tonder Reinier
Published: May 2014

N/A
Endovascular embolisation of a cervical spinal AVF in a patient with NF1
Authors: Mahomed Nasreen , Malatji Phaku , Andronikou Savvas , Modi Mala , Nagdee I A
Published: May 2014

Vascular abnormalities associated with neurofibromatosis type 1 (NF1) are well described. Spinal arterio-venous fistula (AVF), however, is a rare finding in NF1 and may present with neurological symptoms that require treatment. Management of spinal AVFs can be endovascular or surgical. We present a patient with known NF1 and neurological symptoms owing to a spinal AVF demonstrated by imaging, who required a combination of endovascular and surgical management.
Recurrent primary fallopian tube carcinoma presenting with an appendiceal metastasis
Authors: Moller Jacobus , Basson J I , Duminy J L , Potgieter E
Published: May 2014

not applicable
Normal variance in renal size in relation to body habitus
Authors: Harmse Werner S
Published: May 2014

Objective. Renal length determination is common in everyday radiology practice. However, a normal range of kidney sizes may not apply to people of all body habitus. This study investigates this relationship in order to determine normal ranges in relation to body habitus. A secondary aim was to evaluate the relationship of renal size to gender and race.

Methods. Kidney lengths were measured on oblique coronal reformatted CT images of 514 patients who received routine abdominal CT scans for conditions unrelated to renal pathology. The patients had normal serum creatinine levels, no history of renal disease, no renal masses, and normal-appearing kidneys on CT. Weight, height, race and gender of the patients were recorded.

Results. The mean renal length was 108 mm with a standard deviation of 9.82 mm. Statistical analysis demonstrated a relationship between kidney size and body weight and height, both individually and collectively. The most accurate prediction model was ‘kidney size = 49.18 + 0.21 x weight + 0.27 x height’, with a R2-value of 0.32. Additionally, kidneys were generally larger in the white population than in the black, and also in males than females.

Conclusion. Normal renal size varies according to patients' body habitus. This variation can be expressed as a function of body weight and height, which can be represented by a nomogram and used as an easy reference in clinical practice.
Radiographic diagnosis of a rare case of oculo-dento-digital dysplasia
Authors: Parashari Umesh Chandra , Khanduri Sachin , Bhadury Samarjit , Qayyum Fareena Akbar
Published: May 2014

Oculodentodigital dysplasia (ODDD), also known as oculodento-osseous dysplasia, is an extremely rare autosomal dominant disorder with high penetrance, intra- and interfamilial phenotypic variability, and advanced paternal age in sporadic cases. The incidence of this disease is not precisely known, with only 243 cases reported in the scientific literature, suggesting an incidence of around 1 in 10 million people. It is marked mainly by eye abnormalities, craniofacial dysmorphism, dental anomalies, hand and foot malformations, various skeletal defects, and mildly delayed mental development. Neurological changes may appear earlier in each subsequent generation. This case report describes a radiological diagnosis of ODDD based on physical appearance, clinical features and radiographic findings in a 16-year-old girl.
Upper abdominal visceral injury resulting from blunt trauma to the pelvis: a specific variant of shockwave injury?
Authors: Emby Donald Jan
Published: May 2014

Two patients who sustained severe blunt injury to the pelvis without external injury to the upper abdomen or lower chest, yet who were found to have a ruptured solid upper abdominal viscus, are reported. The first patient on delayed arrival revealed clinical features suggestive of intra-abdominal bleeding and was found to have a grade 3 ruptured spleen. With the second patient, upper abdominal injury (in this instance, a pancreatic laceration) was not initially suspected owing to the absence of clinical evidence of injury to the abdomen. It is postulated that both the splenic and pancreatic injuries were the result of a shockwave propagated through the abdomen following the severe external impact to the pelvis.
Visit by RSSA President to Stellenbosch University; Leuven Lung Imaging Course; RSSA MDCT Course
Authors: Sperryn Clive
Published: May 2014

RSSA MDCT Course
CPD Questionnaire
Authors: Fani Gertrude
Published: May 2014

CPD
Acalculous cholecystitis presenting in an outpatient with no risk factors
Authors: Goodier Matthew , Mulira Solomon , Andronikou Savvas
Published: May 2014

Acute acalculous cholecystitis (AAC) is recognised to occur in patients with serious co-morbid illnesses such as after major surgery, severe trauma, burns, multi-organ failure, systemic sepsis and prolonged intravenous hyperalimentation. The development of AAC in outpatients with none of the traditional risk factors appears to be increasing. The incidence of this form of AAC in South Africa has not yet been established. Prompt recognition of this condition and appropriate surgical management is necessary to minimise morbidity and mortality. This report describes a 52-year-old man who developed AAC in the absence of the usual risk factors.
Report on the Introduction to Research for International Young Academics (IRIYA) Seminar, Chicago
Authors: Matzdorff Robert
Published: May 2014

N/A
NECSA and NTP donate PET-CT scanner to Tygerberg Hospital
Authors: Matzdorff Robert
Published: May 2014

N/A
Musculoskeletal imaging of a painful knee
Authors: Misser Shalendra Kumar
Published: May 2014

Musculoskeletal imaging of a painful knee
Image quality dependence on image processing software in computed radiography
Authors: Strauss Lourens Jochemus , Rae William ID
Published: May 2014

Background. Image post-processing gives computed radiography (CR) a considerable advantage over film-screen systems. After digitisation of information from CR plates, data are routinely processed using manufacturer-specific software. Agfa CR readers use MUSICA software, and an upgrade with significantly different image appearance was recently released: MUSICA2.

Aim. This study quantitatively compares the image quality of images acquired without post-processing (flatfield) with images processed using these two software packages.

Methods. Four aspects of image quality were evaluated. An aluminium step-wedge was imaged using constant mA at tube voltages varying from 40 to 117kV. Signal-to-noise ratios (SNRs) and contrast-to-noise Ratios (CNRs) were calculated from all steps. Contrast variation with object size was evaluated with visual assessment of images of a Perspex contrast-detail phantom, and an image quality figure (IQF) was calculated. Resolution was assessed using modulation transfer functions (MTFs).

Results. SNRs for MUSICA2 were generally higher than the other two methods. The CNRs were comparable between the two software versions, although MUSICA2 had slightly higher values at lower kV. The flatfield CNR values were better than those for the processed images. All images showed a decrease in CNRs with tube voltage. The contrast-detail measurements showed that both MUSICA programmes improved the contrast of smaller objects. MUSICA2 was found to give the lowest (best) IQF; MTF measurements confirmed this, with values at 3.5 lp/mm of 10% for MUSICA2, 8% for MUSICA and 5% for flatfield.

Conclusion. Both MUSICA software packages produced images with better contrast resolution than unprocessed images. MUSICA2 has slightly improved image quality than MUSICA.
Radiation protection and the safe use of X-ray equipment: Laws, regulations and responsibilities
Authors: Herbst Charles Petrus , Fick Gerhard H
Published: May 2014

Lately, South Africa’s regulatory framework for electromagnetic medical devices has come under considerable pressure. In this article the legislative framework and regulatory infrastructure are scrutinized, by looking at how the legislature has given form to protective measures against ionizing radiation.

Although the Hazardous Substances Act provides for effective protection against radiation, poor administration led to insufficient staffing levels, uncertainty about Regulations and licensing conditions and therefore undermines a sound radiation protection infrastructure. The legal basis of enforcing licensing conditions through a website without proper consultation with interested and affected parties is questionable and ineffective in controlling radiation levels.

Effective and legal radiation control is possible by activating the National Advisory Committee on Electronic Products provided for in Regulation R326 published in 1979, but never implemented.

The possible impact of annual quality assurance tests currently enforced through licensing conditions on the radiation dose of the population is not cost effective as new training and accreditation structures had to be created. The fact that generally more than 80% of overexposures are caused by human error is a clear indication that training of the daily users of X-ray equipment should be emphasized and not the training and accreditation of the technicians responsible for a single quality assurance test per year.

Constructive engagement with the professional bodies involved in the medical use of X-rays through a National Advisory Committee on Electronic Products may be a cost effective solution for lowering radiation dose to the population.
Ultrasound diagnosis of ulnar nerve dislocation and snapping triceps syndrome
Authors: Gupta Vivek Bhagwat , Patankar Kiran B , Paranjpe Farheen , Patil Jeetendra
Published: May 2014

Dislocation of the ulnar nerve with snapping triceps syndrome has been implicated as a cause of cubital tunnel syndrome. Patients with this condition may clinically present with a snapping sensation at the elbow upon flexion along with ulnar neuropathic symptoms. Though demonstration of this condition is possible by static MRI images, ultrasound can be used as a more accessible and inexpensive modality for attaining diagnosis. This pictorial essay emphasises the technique, findings and role of dynamic ultrasound in the diagnosis of this entity.
Cubital tunnel syndrome: A report of two cases
Authors: Suleman Farhana Ebrahim , Velleman Mark D
Published: May 2014

Cubital tunnel syndrome is the second most common peripheral neuropathy of the upper limb. This is due to the anatomy of the tunnel, the physiological changes that the nerve undergoes during elbow flexion, as well as pathological conditions that occur within the tunnel. We present two cases of ulnar neuropathy occurring at the level of the cubital tunnel, demonstrating that this entity may occur owing to an identifiable cause or may show only signal alteration without a visible cause on MRI.