Browsing by Author "Ahmed, Nazir"

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    Open Access
    Diagnostic yield of ultrasound-guided fine needle aspiration biopsy (US-guided FNAB) and post-surgical histopathological correlation of thyroid nodules in the Department of Radiology, Groote Schuur Hospital, Cape Town, South Africa over a two-year period
    (2022) Matimati, Bornaventure; Ahmed, Nazir
    Background: Nodular thyroid disease is common worldwide, and the incidence of thyroid nodules is increasing globally. Ultrasound (US)-guided thyroid nodule fine needle aspiration biopsy (FNAB) is a reliable and cost-effective method of distinguishing between benign and malignant nodules before major surgery is performed. Aims: The study aimed to establish the diagnostic yield of US-guided thyroid FNAB's done at Groote Schuur Hospital over two years and to correlate findings with histopathological results in those patients that underwent thyroidectomy. Objectives: The objectives were to establish the number of US-guided FNABs performed, the number of repeat FNABs and the number of patients who subsequently had thyroidectomy over two years. A further objective was to evaluate the diagnostic yield by comparing the cytology and histology results for patients that underwent thyroidectomy. Methods: This was a retrospective study of all patients referred for US-guided FNAB from 1 January 2018 to 31 December 2019. All patients with cytology results after FNAB and histology results after thyroidectomy, were included in the study. US-guided FNAB data was collected from the Picture Archiving and Communication System (PACS) and Radiology Information System (RIS), while cytology and histology data were obtained from the National Health Laboratory Services (NHLS). Results: A total of 236 patients were included in the study (220 females and 16 males), with ages ranging from 19 to 82 years. The diagnostic yield was 34-% on the first, 36-% on the second and 48-% on the third FNAB. Most of the US-guided FNABs were non-diagnostic (66- % on the first, 64-% on the second and 52-% on the third FNAB). A total of 107 patients (45 %) had a repeat FNAB, while 23 patients (9.7-%) had a second repeat FNAB. A total of 48 patients (20.3-%) underwent thyroidectomy. Cancer was detected in 29/236 (12.3-%), of which 17/29 (59-%) were papillary thyroid carcinomas. There was no significant correlation between FNAB results and post-surgical histopathological results in patients who underwent thyroidectomy, with a p value of .15. Conclusion: The overall cancer rate of 12.3-% was comparable with that of other institutions. 66-% of US-guided FNABs were non-diagnostic, while 34-% were diagnostic on the first FNAB with 45-% requiring a repeat second FNAB. The assistance of a cytopathologist during the biopsy has been known to result in fewer non-diagnostic results, avoiding repeat attempts. Further diagnostic and cost-effective analysis of cytopathology assistance in the US-guided FNAB for characterising thyroid nodules is advised.
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    Open Access
    Evaluating the yield of brain CT examinations in patients presenting with first onset seizures at the Groote Schuur Hospital, Cape Town
    (2019) Ncube, Innocent Vusumusi; Ahmed, Nazir
    Background: Seizures are a frequent and potentially significant presenting complaint to the emergency department (ED). Determining the underlying cause for seizures is important in guiding further clinical management of patients. ED physicians at Groote Schuur Hospital, Cape Town, South Africa routinely request Computed Tomography (CT) brain scans in the work-up of patients presenting with first onset seizures. Objectives: To determine the number and proportion of CT scan examinations with abnormal findings in patients presenting with first onset seizures at the Groote Schuur Hospital ED, Cape Town, South Africa and to identify the range of CT abnormalities. Method: A retrospective study was carried out in the Division of Radiology, Groote Schuur Hospital. Patients who presented to the ED with first onset seizures and who underwent brain CT examination as part of their work up between 1 January 2013 and 31 December 2016 were enrolled. All patients presenting to the ED with first onset focal or grand mal seizures were included. Patients with recent trauma and those with previously diagnosed epilepsy were excluded. Results: A total of 200 patients were eligible for the study. Of these, 92 (46%) patients with first onset seizures had an abnormality or abnormalities on brain CT scan. Of those patients whose HIV status was known, 50% of HIV positive and 53% of HIV negative patients had abnormal CT scans. 54% of patients with focal seizures and 38% with generalised seizures had an abnormality on CT scan. Abnormalities found on CT scans included chronic cerebral infarction (7.5%), acute or subacute cerebral infarction (4.5%), neurocysticercosis (7.0%), other infections (6.5%), haemorrhage and other vascular lesions (6.5%), post-traumatic encephalomalacia (6.5%), primary brain tumours and metastases (based on CT characteristics) (7.0%). Conclusion: Forty-six (46%) of patients presenting to the Groote Schuur Hospital ED, Cape Town, South Africa with first onset seizures had an abnormality on their brain CT scans. Brain CT scan is therefore recommended in patients presenting to the ED department with first-onset seizures, irrespective of their HIV/ neurological status.
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    Open Access
    Identifying non-value added waste that delay emergency CT brain workflow using lean management principles
    (2020) van Zyl, Carike; Weimann, Edda; Ahmed, Nazir
    Introduction: The Department of Radiology at Groote Schuur Hospital receives numerous emergency CT brain requests especially from the Emergency and Trauma departments. Improvement in emergency CT brain workflow should reduce waiting times for CT scans resulting in earlier diagnosis and treatment of these patients. Identification of the nonvalue-added waste (NVAW) (steps regarded as wasteful to the customer) in the CT brain workflow can be determined by use of a lean management tool namely a value stream map (VSM - a flow analysis of information required to provide service to the customer). AIM: The study aims to identify non-value-added waste in the CT brain workflow value stream map which may result in delay in emergency CT brain reporting. Method: This study investigated NVAW in emergency CT brain workflow for 5 working days between 08h00 to 22h00 from Monday to Friday. Nineteen patients booked for an emergency CT brain scan by the Emergency Department (ED) only between 08h00 and 22h00 over the specific 5 day working period were randomly selected using convenience sampling. The indications for emergency CT brain scans in the sample were similar to the wider group of patients undergoing emergency CT brain scans. A VSM identifying all the relevant steps in the emergency CT brain workflow was constructed. The investigator accompanied each of the nineteen patients from the ED to the CT scanner and back and manually recorded the time elapsed in minutes for each separate step on the data collection sheet. The outstanding information required was obtained from the Xiris system on the Phillips PACS (Picture Archiving and Communicating System). The average time interval for each of the steps as indicated on the VSM was calculated, and the rate limiting step(s) which resulted in a delay in emergency CT brain reporting was identified. Results: Overall, the longest step was the time interval from the time of completion of the scan to the generation of the report (turnaround time (TAT)) with an average time of 72.21 minutes (p value of < 0,01). Conversely, the time interval from placing the request by the clinician on the PACS to the time of annotation by the radiologist was the shortest with an average time of 5.84 minutes. Discussion: The lean management system was used to identify the rate limiting step(s) which resulted in delay in emergency CT brain reporting. Possible reasons identified for the delay caused by the rate limiting step include the backlog in reporting of the large number of already scanned cases which may be due to staff constraints as only one radiologist was on duty during most of the study period. Additional contributory factors include clinician telephonic query interruptions to radiology registrars during reporting sessions and delay in the emergency doctor authorising and facilitating transport of the patient from the emergency unit to the CT scanner. Conclusion: The value stream map tool in lean management can be utilised to identify non value added waste in emergency CT brain workflow.
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    Lateral atlanto-dens interval variation in a normal South African population using Computed Tomography
    (2019) Schoombee, Hendrik Bellingan; Ahmed, Nazir
    Rationale On routine Computed Tomography (CT) scans for suspected trauma of the cervical spine, the lateral atlanto-dens interval (LADI) is routinely observed and can readily be measured. Although values greater than the upper limit of normal may indicate atlanto-axial subluxation or ligament rupture, it is uncertain what the upper limit of normal for this measurement is, and whether this is a reliable indicator of injury to this region. The overall importance of this measurement in the setting of trauma is not well understood, as may be seen by the numerous conflicting previous studies. A step in the direction of resolving this uncertainty is to determine the range of normal measurements and their variability in a population cohort. Method A total of 201 patients were included in this study after meeting the inclusion criteria that the CT head scans were performed for reasons other than trauma and included the upper spine. Exclusion criteria included patients with any history of prior trauma or known congenital or pathological conditions of the upper neck. The lateral atlanto-dens interval (LADI) was measured on these patients and any asymmetry between the left and right sides was calculated. The degree of head rotation on every patient was recorded and plotted against LADI asymmetry. Results The mean LADI asymmetry was calculated at 0.810 mm with a standard deviation of ±0.724 mm. The largest LADI asymmetry that was measured was 4.7 mm. There was no statistical difference between male and female LADI measurements, nor with asymmetry. For the left and right side LADI’s in our group of patients, the Two One-Sided T-test (TOST) returned a p-value of <0.0001, with a 1 mm tolerance (upper and lower equivalence limit) on either side, suggesting that there was no statistical difference between the sides (region of statistical equivalence of 2 mm) within 2 mm measurement. No statistically significant correlation between head rotation and LADI asymmetry could be established, with the Pearson test returning a p-value of 0.063. Discussion It has long been proposed that LADI asymmetry could be used as a marker for possible injury to the cervico-cranial junction, more specifically with burst-type fractures of the atlas with asymmetrical displacement of the lateral masses In our normal study group, no statistically significant difference between the left and right LADI measurements was demonstrable, allowing a region of statistical equivalence of 2 mm. This agrees with the findings of some previous studies. Only 13 (6.5%) of 201 of the patients in our study had LADI asymmetry of more than 2 mm. Numerous factors potentially influencing LADI measurement such as congenital anomalies and head position have been mentioned in previous work. In our study, however, no direct correlation between the patient’s head rotation and LADI asymmetry could be established. Conclusion Findings in our sample of patients supported the use of 2 mm as the upper limit of normal for LADI asymmetry, which is similar to that concluded by previous studies. Rotation of the head and spine did not influence measurements significantly. However, a possible factor that may influence LADI asymmetry measurement and limit its usefulness as a tool in predicting injury is lateral flexion of the cervical spine. This falls outside the scope of this study, but further work on this aspect may be useful.
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    Open Access
    Normal variations of coeliac and hepatic artery blood supply to the liver as identified on multidetector computed tomography (MDCT) studies at Groote Schuur Hospital, Western Cape Province, South Africa between 2018 and 2019
    (2020) Muzenda, Vengesai; Ahmed, Nazir
    Background: Variant anatomy of the coeliac axis and hepatic arterial system is not uncommon and with the evolution of new minimally invasive surgical techniques and endovascular hepatic therapies, the interventional radiologist should have a good knowledge of the normal and variant anatomy to optimize treatment and minimise iatrogenic liver injuries. Objectives: To analyse, describe and illustrate the prevalence of the normal and variant anatomy of the coeliac axis and hepatic arterial system. Methods: A total of 300 MDCT angiography studies performed during a two-year period at Groote Schuur Hospital, Western Cape Province, South Africa were retrospectively reviewed to assess for the normal and variant anatomy of the coeliac axis and hepatic arterial system. Results: The CA and HA variations were analysed as per criteria by Uflacker's and modified Michel's respectively. The normal CA was seen in 88.3% (n=265). Most common variant anatomy was the hepatosplenic trunk seen in 2% (n=6). The remaining 3% (n=9) of patients were unclassified. Normal HA was seen in 55% (n=165). The most common variant anatomy was the accessory LHA seen in 12.7% (n=38). Classified HA variant anatomy was 30.7% and the remaining 14.3 % were unclassified. Double hepatic artery (2.7%) and CHA trifurcations (5.3%) were very common variants. Novel variants such as CHA off the SMA in combination with another variant in the form of accessory LHA (0.7%; n=2), combined double hepatic artery with an accessory LHA (0.3%; n=1) as well as accessory LGA off the PHA (0.3%; n=1) were identified. Conclusion: Variant coeliac axis and hepatic arterial anatomy is very common. Our population study demonstrated a greater prevalence of an accessory LHA than that reported in the literature. Although the rest of the variant frequencies were comparable to literature studies cited, novel hitherto undescribed variants were identified which the radiologist and hepatic surgeons need to be aware of. Two such variants were a persistent communication between SMA and CHA, and an accessory left gastric artery off the PHA.
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    The solvent extraction and separation of the tetrachloroplatinate (2) and -palladate (2) ions in the presence of stannous chloride into methylisobutylketone
    (1983) Ahmed, Nazir; Koch, Klaus
    The potentialities of extracting platinum(!!) and palladium(II) selectively as complexes of [M(SnCl3)nCl4-nJ2 - (M=Pt,Pd) was examined. A study was made of the effect of SnCl2 on the solvent extraction of K2PtCl4 and K2PdCl4 from solutions containing various concentrations of HCL into methylisobutylketone (MIBK) /hexane mixtures. It was found that increasing SnCl2 concentrations dramatically increases the efficiency of extraction of platinum into the organic phase. In the presence of a five-molar excess of SnCl2, platinum is quantitatively extracted. In contrast, palladium is not quantitatively extracted under similar conditions. Our studies show that the percentage extraction of platinum and palladium depends upon the Sn(II) :M(II) ratio, the HCL, H+ and c1- concentrations and the equilibration time as well. Studies were also carried out to investigate the possibility of separating platinum and palladium by varying the amount of SnCl2 present. Results obtained showed that the separation was dependant on the HCL concentration of the aqueous phase and the composition of the organic phase. The effects of macro amounts of palladium and excess tin on the separation process was also examined. A preliminary study of the effect of four base metals on the separation was undertaken.
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    Widened mediastinum on chest radiography as a prompt for further imaging in suspected blunt traumatic aortic injury: 3-year experience at a major trauma centre
    (2022) Dzamatira, Davison; Ahmed, Nazir
    Background: Trauma clinicians utilise the presence of a widened mediastinum on a chest radiograph (CXR) as the commonest indication for chest computed tomography (CT) in cases of suspected blunt traumatic aortic injury (BTAI). Evaluating the practical implementation and accuracy of this tool could improve the degree of interdepartmental agreement on its correct application. Objectives: To establish the proportion of requests by requesting clinicians citing a widened mediastinum on radiography that met the established criteria for true widening. A secondary objective was to determine the percentage of confirmed blunt traumatic aortic injury and other serious injuries in our study population at Groote Schuur Hospital. Methods: A retrospective descriptive study was conducted measuring the mediastinal widths on chest radiographs of all patients suspected of BTAI that had chest CT at Groote Schuur Hospital over a three-year period from 01 January 2017 to 31 December 2019 to establish the accuracy of this sign as a predictor of aortic injury. Results: In total, 223 patients had chest CT performed to exclude BTAI. 85.7 % of clinicians' requests for chest CT met the current criteria for a widened mediastinum on supine CXR or LODOX. Aortic injury was confirmed in 4 patients (2%). Other serious injuries included thoracic vertebral fractures of at least one vertebral body which was present in 19 patients (8.5%), and 1 patient (0.45%) had a diaphragmatic rupture. None of the patients had a cardiac injury. 200 out of 223 patients (89.7%) had neither an aortic injury nor any of the serious injuries described above. Conclusion: The study demonstrated a high level of accuracy by clinicians in diagnosing widening of the mediastinum on LODOX and CXR. These findings can be used to further improve interdepartmental agreement in the evaluation and management of patients with suspected BTAI.