SA Journal of Radiology - Volume 18, Issue 1, 2014
Volume 18, Issue 1, 2014
The radiological appearance of intracranial aneurysms in adults infected with the human immunodeficiency virus (HIV) : original researchSource: SA Journal of Radiology 18, pp 1 –4 (2014) http://dx.doi.org/http://dx.doi/org.10.4102/sajr.v18i1.586More Less
Background : The global prevalence of intracranial aneurysms is estimated at 2.3%. Limited literature is available on intracranial aneurysms in HIV-infected patients.
Objectives : To describe the radiological appearance of intracranial aneurysms in HIV-positive adults.
Method : In this retrospective analysis of data, 23 HIV-positive patients, of which 15 (65.2%) were female, with a total of 41 aneurysms were included. The mean age was 38 years, and their median CD4 count was 305 x 106/L. Inclusion criteria comprised subarachnoid haemorrhage and confirmed intracranial aneurysms on four-vessel angiography.
Results : Fifteen (65.2%) patients had a single aneurysm, of which 12 (80.0%) had a saccular appearance. Seven (46.7%) of the single aneurysms had a neck width larger than 50% of the transverse aneurysm sac size. The mean longitudinal diameter of the aneurysm sac was 4.9 mm and the transverse diameter 4.4 mm. More than half of these aneurysms occurred at the anterior communicating artery. The median CD4 count of single-aneurysm patients was 319 x 106/L. Eight patients (34.8%) had multiple aneurysms, with a total of 26 aneurysms (range 2-6 aneurysms per patient), of which 13 (50.0%) had a complex appearance. Twenty-four (92.3%) of the multiple aneurysms had a neck width larger than 50% of the transverse aneurysm sac size. The mean longitudinal diameter of the aneurysm sac was 4.0 mm and the transverse diameter 3.9 mm. The multiple aneurysms occurred more commonly in the internal carotid artery. These patients had a median CD4 count of 294 x 106/L.
Conclusion : HIV-associated intracranial aneurysms occur at a younger age, appear to be saccular and complex in shape, with a wide neck, and might rupture at small sizes.
Author Razaan DavisSource: SA Journal of Radiology 18 (2014) http://dx.doi.org/http://dx.doi/org.10.4102/sajr.v18i1.610More Less
We take cognisance of the 50 years since the South African Journal of Radiology (SAJR) first appeared as a supplement of the South African Medical Journal (SAMJ) in April 1963. Although not in continuous print, it nevertheless documented the development of South African radiology, serving as a repository for the mostly unique and always interesting cases.
Source: SA Journal of Radiology 18, pp 1 –3 (2014) http://dx.doi.org/10.4102/sajr.v18i1.585More Less
Pseudomyxoma peritonei is a rare complication of mucinous tumours of appendiceal or ovarian origin. Other associations are malignancies of the colon, urachus and biliary tree. Large amounts of extracellular and peritoneal mucin result in distortion and loss of function of visceral organs. Currently, radiology plays a critical role in diagnosing this rare entity, in follow-up and in predicting the outcome of cytoreductive surgeries.
Multi-detector computed tomography radiation doses in the follow-up of paediatric neurosurgery patients in KwaZulu-Natal : a dosimetric audit : original researchSource: SA Journal of Radiology 18, pp 1 –4 (2014) http://dx.doi.org/10.4102/sajr.v18i1.588More Less
Background : Multi-detector computed tomography (MDCT) is the preferred modality for follow-up of paediatric neurosurgery patients. Serial imaging, however, has the disadvantage of an ionising radiation burden, which may be mitigated using the 'as low as reasonably achievable' (ALARA) principle.
Objectives : The primary objectives were to determine the radiation dose exposure in paediatric patients subjected to MDCT imaging following neurosurgery and to compare these values with references in current literature. Our secondary objective was to assess the relationship between radiation dose and clinical scenario.
Method : Retrospective descriptive data were collected from all paediatric postsurgical patients (n = 169) between the ages of 0 and 12 years who had their first followed-up scan in the year 2010 and were followed up for six months or less. Dose-length product (DLP) and current-time product were collected from the picture archiving and communication system. Demographic data including radiology reports were collected from the hospital information system. The effective doses (ED) were calculated from the corresponding DLP using age-adjusted conversion factors. For purposes of comparison with other studies, median dosimetric values were calculated and the children were grouped into three age ranges, namely younger than 3 years, 3-7 years and 8-12 years old.
Results : The highest median radiation doses were noted in patients being followed-up for intracranial abscesses (1183 mGy cm) in the 8-12 year age group, most of whom were female. The lowest radiation doses were for intracranial shunt follow-ups (447 mGy cm). Median values for DLP, ED and current-time product (mAs) were comparable to reference doses in all three age groups. However, our study showed a much broader distribution of values with higher upper limits relative to reference values. Indications for follow-up included shunts (n = 110; 65%), intracranial abscess (n = 31; 18%), subdural haematoma (n = 13; 8%) and tumour (n = 6; 4%). Head trauma only accounted for 5% of the cases.
Conclusion : The median radiation doses measured were comparable to values in literature and therefore deemed acceptable. The wider dose distributions of all three dosimetric parameters (DLP, ED and mAs) were attributed to inappropriate use of scan length and reference effective mAs. Adherence to recommended scan length protocols should be encouraged. Evaluation of the current use of reference effective mAs is needed and will require a separate study to determine the smallest value that can be used without compromising image quality. Further dose reductions could be achieved by omission of unenhanced scans in the follow-up of intracranial abscesses. It is recommended that diagnostic reference levels specific to South African clinical scenarios be developed to make local dosimetric audits more relevant.
Author Charles S. WiysongeSource: SA Journal of Radiology 18, pp 1 –2 (2014) http://dx.doi.org/10.4102/sajr.v18i1.609More Less
Mindful of the dangers of making healthcare decisions without reference to trustworthy evidence, a new approach to healthcare delivery was introduced in the late 1970s. This approach, referred to as evidence-based medicine or more broadly as evidence-based health care, is defined as 'the conscientious, explicit, and judicious use of current best evidence' in making healthcare decisions. Evidence-based health care integrates individual healthcare expertise, patient values and preferences, and the best available research evidence from systematic reviews. See Boxes 1 and 2 for key definitions and resources for evidence-based health care respectively.
The accuracy of after-hour registrar computed tomography (CT) reporting in a South African tertiary teaching hospital : original researchSource: SA Journal of Radiology 18, pp 1 –3 (2014) http://dx.doi.org/10.4102/sajr.v18i1.591More Less
Background: The Division of Radiodiagnosis at Tygerberg Academic Hospital, a 1384-bed tertiary training institution in Cape Town, South Africa provides a comprehensive 24-hour clinical radiology service, and has a duty registrar on-site at all times. The demand for computed tomography (CT) imaging is increasing and plays a pivotal role in patient management.
Objectives: The purpose of this study was to determine the accuracy of after-hour registrar CT reporting, to identify possible factors that may affect the error rate, and to assess whether or not errors had any clinical impact.
Method: A set of senior registrar reports (provisional reports) issued during a 28-day period was compared with the corresponding consultant reports (final reports). Discrepancies were identified and quantified, based on their impact on patient management.
Results: The overall discrepancy rate was 8% (18 out of 225) and the overall accuracy rate was 92% (207 out of 225). The major error rate was 4% (9 out of 225) and the minor error rate was also 4% (9 out of 225).
Conclusion: We observed that the accuracy of after-hour CT reporting by senior registrars at the Division of Radiodiagnosis at Tygerberg Hospital was on par with international standards. We investigated three factors which may have affected discrepancy rates, and only found one factor, namely the time of day, to be significant. Steps can be taken to create awareness of this fact amongst registrars, which hopefully would result in improved patient care and management.
Author A. Fourie BezuidenhoutSource: SA Journal of Radiology 18 (2014) http://dx.doi.org/10.4102/sajr.v18i1.597More Less
Persistent hyperplastic primary vitreous (PHPV) is a congenital lesion due to incomplete regression of the embryonic ocular blood supply (hyaloid vasculature). It represents 28% of childhood presentations of leukocoria and is almost always accompanied by poor vision, micropthalmia and often retinal detachment. The absence of ocular calcifications helps distinguish PHPV from the more common retinoblastoma.
Source: SA Journal of Radiology 18, pp 1 –3 (2014) http://dx.doi.org/10.4102/sajr.v18i1.594More Less
'Hydatid' originates from the Greek word meaning 'watery vesicle'. It refers to a cyst formed as a result of infestation by larvae of the tapeworm Echinococcus granulosus, endemic to sheepraising areas of the world. Humans are an accidental intermediary host, with lungs and liver most commonly affected. Hydatid involvement of the spine accounts for less than 1% of the total cases of hydatid disease and isolated extradural involvement is even rarer. We report a case of extradural hydatid cyst involving a boy of 5 years.
Incidental right Bochdalek hernia with interruption of the inferior vena cava and hepatic venous collateral continuation : a case reportSource: SA Journal of Radiology 18, pp 1 –3 (2014) http://dx.doi.org/10.4102/sajr.v18i1.592More Less
A 36-year-old asymptomatic female had a routine chest radiograph to exclude pulmonary tuberculosis, as part of an employee wellness programme. There was opacification of the right lower thorax. Computed tomography and venography demonstrated an incidental right Bochdalek hernia with interruption of the inferior vena cava (IVC) and hepatic venous collateral continuation. The association of a Bochdalek hernia with an anomaly of the IVC is rare, with only one case described in the literature.
Source: SA Journal of Radiology 18, pp 1 –5 (2014) http://dx.doi.org/10.4102/sajr.v18i1.595More Less
This article presents a description of tele-nuclear medicine and, after outlining its history, a wide, representative range of its applications. Tele-nuclear medicine has benefited greatly from technological progress, which for several decades has provided greater data transfer rates and storage capacity at steadily decreasing cost. Differences in the practice of nuclear medicine between developed and developing countries arise mainly from disparities in their available infrastructure, funding and education levels of personnel involved. Consequently there are different emphases in their tele-nuclear medicine, which are elaborated. It is concluded that tele-nuclear medicine is important for all countries, but the emphasis on its application may differ between developed and developing nations, with an emphasis on distance learning in the latter.
In vivo determination of renal stone composition with dual-energy computed tomography : original researchSource: SA Journal of Radiology 18, pp 1 –5 (2014) http://dx.doi.org/10.4102/sajr.v18i1.605More Less
Background : Composition of renal stones influences management of patients with renal stone disease. Currently stone composition can only be analysed ex vivo after stone extraction or passage, but recent introduction of dual-energy computed tomography (CT) to clinical practice has raised interest in the ability of this technology to determine composition of renal stones in vivo.
Objectives : To determine renal stone composition in patients using single-source dual-energy rapid-peak kilovolt (kVp) switching CT.
Method : Nineteen patients with renal stones for percutaneous nephrolithotomy were evaluated with single-source dual-energy computed tomography on a Discovery CT 750HD. The Gemstone Spectral Imaging (GSI) effective atomic number (Zeff) and attenuation at 70 keV monochromatic energy were used to predict the stone composition. Infrared spectroscopy and x-ray diffraction of stones after extraction served as the reference standard.
Results : Two (10.5%) of the 19 stones had uric acid as major component. The other 17 (89.5%) were calcium-based stones. No statistically significant difference between the GSI Zeff and calculated effective atomic number (Z) for stone compounds was found. The GSI Zeff and attenuation could differentiate between uric acid and non-uric acid stones. No differentiation between different calcium stones could be made.
Conclusion : Uric acid and non-uric acid renal stones can be differentiated with single-source dual-energy in vivo. The GSI Zeff reflects the dominant material in polycrystalline stones.
The prevalence of undiagnosed abnormalities on non-contrast-enhanced computed tomography compared to contrast-enhanced computed tomography of the brain : original researchSource: SA Journal of Radiology 18, pp 1 –7 (2014) http://dx.doi.org/10.4102/sajr.v18i1.598More Less
Background : Even though magnetic resonance imaging (MRI) is the gold standard investigation for intracranial pathology, it is not widely available in developing countries and computed tomography (CT) of the brain remains the first-line investigation for patients with suspected intracranial pathology. It is generally accepted that certain intracranial pathology can be missed on non-contrast-enhanced CT (NECT) of the brain if a contrast-enhanced CT (CECT) is not done. We have to consider on the one hand the risk of delayed or missed diagnosis and on the other hand the cost, increased radiation exposure and contrast-induced reactions. Advances in CT technology have also improved the resolution of CT scan images, making it easier to identify pathology on an NECT of the brain. To date, no study comparing NECT to CECT of the brain, utilising 64-slice CT technology, has been published.
Objectives : To determine the prevalence of undiagnosed abnormalities on non-contrast-enhanced computed tomography (NECT) scans of the brain reported as normal, on a 64-slice CT scanner.
Method : A descriptive retrospective study was undertaken of CT brain scans done during a 12-month period at a tertiary provincial hospital in the Northern Tshwane district of Gauteng, South Africa. The CT brain scans were evaluated by three reviewers (general radiologists). The NECT and contrast-enhanced computed tomography (CECT) scans of the brain were reviewed independently on separate occasions. Reviewers were blinded to patient history, each other's interpretation, and to their own interpretation of the NECT when evaluating the CECT and vice versa. Discrepancies in interpretation were resolved during a consensus meeting between all three reviewers. The reviewers also re-evaluated the NECT scans of the cases with undiagnosed abnormal findings during this session. A decision was made pertaining to the visibility of the abnormal findings on the NECT scan.
Results : In this study, 3.28% of cases had abnormal findings undiagnosed by three reviewers on the NECT scans. Re-evaluation by the panel reduced this to 1.42%, indicating a reading error of 1.85%.
Conclusion : There is a small prevalence of missed abnormal findings on the NECT scan when using only NECT. Omitting unnecessary CECT will reduce the radiation exposure to the patient and reduce the risk of adverse events from the use of intravenous iodinated contrast. Alternatively, doing only a CECT scan would reduce the risk of missing abnormal findings and would also decrease the patient's exposure to radiation.
Author Lynda Albertyn-CrossSource: SA Journal of Radiology 18, pp 1 –2 (2014) http://dx.doi.org/http://dx.doi/org/10.4102/sajr.v18i1.711More Less
Christian George Albertyn was born on 13 December 1920 in Bethal, Transvaal (South Africa). He moved to Middelburg and then Pietermaritzburg, where his father Dr Christopher James Albertyn was the district surgeon and who later served on the Gluckman Commission to investigate the setting up of a national health service in the 1930s.
A retrospective study of computed tomography angiography versus digital subtraction angiography in penetrating neck trauma at Groote Schuur Hospital, South Africa : original researchSource: SA Journal of Radiology 18, pp 1 –7 (2014) http://dx.doi.org/10.4102/sajr.v18i1.601More Less
Background: Penetrating neck trauma is commonly encountered in South African trauma units, and is associated with high mortality and morbidity rates. The imaging protocol for stable patients with penetrating neck trauma remains controversial. There is only sparse data validating the use of computed tomography angiography (CTA) in the evaluation of penetrating neck trauma in South Africa.
Objectives: To assess the sensitivity and specificity of CTA versus digital subtraction angiography (DSA) in detecting arterial injury and secondarily evaluate the ability of CT to assess non-arterial injury.
Method: Using hospital and radiology databases, 23 patients were identified who had undergone both CTA and DSA for penetrating neck trauma. The data was retrospectively anonymised and randomised. A radiologist experienced in the interpretation of both trauma CTA and DSA re-reported all the imaging and the findings were compared and analysed.
Results: Twenty-four arterial injuries were detected. The sensitivity of CTA for detecting arterial injury was 78% and the specificity 83%. The ability of CTA to delineate wound track and detect non-arterial visceral injury was also confirmed.
Conclusion: CTA is an attractive initial diagnostic investigation that, along with clinical evaluation, effectively guides further investigation and intervention. It is important for the radiologist to understand the limitations of CTA and have a low threshold for DSA in equivocal cases.
Author Shalen MisserSource: SA Journal of Radiology 18, pp 1 –3 (2014) http://dx.doi.org/10.4102/sajr.v18i1.705More Less
Several answers to the quiz question were received from all quarters of the country. Noteworthy responses came from Drs Ian Haynes, Nikelo Mabandla, Francois Roux, Mlindeli Masango, Andrew Lawson, Zakariya Vawda and Zain Ally. Spot-on diagnoses with the best radiological descriptions obtained were from Dr Naye Sihlali and Dr Fourie Bezuidenhout, who share the prize. Congratulations to all respondents.
Source: SA Journal of Radiology 18, pp 1 –3 (2014) http://dx.doi.org/10.4102/sajr.v18i1.622More Less
The ivy sign refers to diffuse bilateral leptomeningeal enhancement on post- contrast T1-weighted magnetic resonance imaging (MRI) and increased signal intensity in bilateral subarachnoid spaces and perivascular spaces on T2-weighted fluid attenuation inversion recovery (FLAIR) MRI sequences in patients with moyamoya disease.