Saudi Cultural Missions Theses & Dissertations
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Item Restricted AUTOMATED RADIATION DOSE MONITORING IN COMPUTED TOMOGRAPHY: A COMPREHENSIVE EVALUATION OF CLINICAL EFFECTIVENESS, ADOPTION, AND USER EXPERIENCE(Saudi Digital Library, 2026) ALanazi, Mohammed; Tavakoli Taba, Amir; Ekpo, Ernest; Kench, PeterAim: This thesis investigated the role of automated dose monitoring systems (DMS) in computed tomography (CT) radiation dose monitoring and optimisation. Method: A multi-method research design comprising two systematic reviews and three empirical studies was undertaken. The first review evaluated the use of DMS high-dose alert functions and their impact on CT dose optimisation, while the second examined DMS applications, benefits, and challenges in CT practice. The third study surveyed CT dose monitoring practices and DMS adoption in Australian radiology facilities. The fourth study explored the experiences of medical physicists and radiographers using DMS in CT. The final study retrospectively assessed a DMS's ability to detect high-dose CT events at an Australian radiology facility. Results: Study 1 showed that DMS systems are valuable for identifying high-dose events and supporting dose optimisation. Study 2 showed that DMS systems facilitate benchmarking, tracking and estimation, although challenges related to data inconsistencies and integration issues were reported. Study 3 found although most Australian radiology facilities performed CT dose assessments, these were commonly undertaken annually using traditional methods, and 41% used DMS. Study 4 showed that DMS users reported improved workflow efficiency, CT dose assessment, and radiation protection practices, although challenges related to system setup, data validation and IT infrastructure were identified. The final study found that 851 of 11,865 CT examinations (7%) triggered DMS alerts, most commonly in spine, joint, and abdomen–pelvis CT exams, with contributing factors related to patients and operators. Conclusion: Automated DMS systems support CT dose monitoring and optimisation through continuous dose assessment, benchmarking, and identification of high-dose events. Wider adoption, supported by appropriate implementation and training, would strengthen radiation protection and enhance patient safety.8 0Item Restricted Effectiveness of Photon-Counting CT for Metal Artefact Reduction in Musculoskeletal Imaging: A Structured Literature Review(Saudi Digital Library, 2026) Almutairi, Abdullah Nasser; Kim, AllanAbstract Aim: This structured literature review systematically evaluated the effectiveness of photon-counting detector computed tomography (PCD-CT) for reducing metal artefacts in musculoskeletal imaging involving orthopaedic implants. Background: Metal artefacts from orthopaedic implants substantially degrade diagnostic image quality in conventional computed tomography, compromising visualisation of periprosthetic anatomy essential for detecting complications. With arthroplasty procedures increasing substantially and photon-counting CT recently introduced into clinical practice (2021), systematic evidence synthesis was required to establish effectiveness, identify optimal imaging parameters, and determine clinical implementation readiness. Methods: A structured literature review was conducted following PRISMA guidelines. PubMed was searched for studies published between 2019 and 2024 evaluating PCD CT for metal artefact reduction in musculoskeletal imaging. Included studies were appraised using the QUALSYST quality assessment tool. Data were extracted systematically and synthesised narratively, examining quantitative artefact metrics, subjective image quality assessments, and optimal reconstruction parameters. Results: Five studies (134 patients plus phantom investigations) met inclusion criteria, achieving good to excellent methodological quality ratings (73.1%-100%). PCD-CT demonstrated substantial artefact reductions ranging from 59% to 83%, substantially exceeding the 30-50% reductions typically achieved with conventional approaches. Virtual monoenergetic imaging at 100-140 keV combined with iterative metal artefact reduction algorithms emerged as optimal reconstruction strategies. Radiologists consistently rated PCD-CT reconstructions as superior to comparator conditions, with enhanced visualisation of periprosthetic bone, soft tissues, and adjacent anatomical structures. Evidence limitations included modest sample sizes, single-vendor concentration, predominance of retrospective designs, and absence of patient-important outcome measures. Conclusion: PCD-CT represents a significant technological advancement, providing substantial and reproducible improvements in metal artefact reduction and image quality in musculoskeletal imaging. Current evidence supports cautious clinical implementation in centres with access to photon-counting CT systems, whilst highlighting essential research priorities including larger prospective studies, multi-vendor evaluations, broader implant representation, and patient-centred outcome research.13 0Item Restricted Comparative analysis of magnetic resonance imaging- and computed tomography-based finite element approaches in estimating bone strength in children(Saudi Digital Library, 2025) Alasmari, Nayef Mohammed; Li, Xinshan; Offiah, AmakaThis PhD thesis compares magnetic resonance imaging (MRI)- and computed tomography (CT)-based finite element analysis (FEA) in estimating bone strength in children. A systematic review and meta-analysis (Chapter 3) was conducted and confirmed the reliability of MRI and FEA in assessing bone material properties and strength in adults but revealed limited paediatric research, identifying only one study. As segmentation is a critical step in FEA, we then conducted a comparative study (Chapter 4) to assess the accuracy and efficiency of ITK-SNAP, 3D Slicer and Amira™ using paired paediatric CT/MRI scans. ITK-SNAP and Amira™ were the most accurate, while 3D Slicer provided comparable results with greater efficiency and was selected for this thesis. Chapter 5 outlines the methodology used to compare MRI- and CT-based FEA in estimating bone strength in children without (n = 9; Chapter 6) and with (n = 8; Chapter 7) bone disease. In children without bone disease, MRI- and CT-based FEA exhibited strong correlation for tensile (ICC = 0.83) and moderate correlation for compressive (ICC = 0.61) failure loads, with MRI-based FEA consistently underestimating the failure loads. In children with bone disease, the modalities demonstrated moderate correlation for tensile (ICC = 0.60) and fair correlation for compressive (ICC = 0.40) failure loads, with similar underestimation of failure loads by MRI-based FEA. Discrepancies between MRI- and CT-based FEA tensile and compressive estimates did not significantly differ between children without and with bone disease (p = 0.386 and p = 0.441, respectively). Chapter 8 summarises the findings, limitations and future directions. Overall, MRI-based FEA showed similar trends to CT-based FEA in estimating bone strength in children, despite underestimating failure loads, particularly in proximal femurs and under compressive loading. With continued improvements in MRI resolution and FEA modelling, MRI-based FEA holds potential as a radiation-free alternative for paediatric bone strength assessment.55 0Item Restricted CT Texture Characterisation of Perirenal Fat in Patients with Upper Urinary Tract Cancers(Saudi Digital Library, 2025-05) Al Mopti, Abdulrahman; Chunhui, LiThis thesis investigates the diagnostic and prognostic potential of perirenal fat (PRF) radiomics in upper urinary tract cancers through three interconnected studies. Using computational techniques to extract quantitative features from CT images, the research establishes PRF as a valuable biomarker for tumour behaviour assessment. The first study, examining clear cell renal cell carcinoma in 474 patients, demonstrates that models integrating tumour features, PRF radiomics, and clinical variables achieve high accuracy for tumour grade (AUC 0.780) and stage prediction (AUC 0.829). Analysis reveals that PRF regions at 4-10mm radial distances from tumours contain the most predictive information. The second study on upper tract urothelial carcinoma (UTUC) reveals excellent performance of combined models in predicting tumour grade (AUC 0.961) and stage (AUC 0.852). PRF-only models also show substantial discriminative capability, confirming that PRF contains distinct textural patterns associated with tumour aggressiveness. The final study establishes the prognostic value of PRF radiomics in UTUC through survival analysis, with the combined radiomics-clinical model achieving a C-index of 0.784. Key radiomics features emerge as strong prognostic indicators, particularly when integrated with clinical variables like stage and hydronephrosis. Methodologically, the research develops a semi-automated approach for PRF analysis and implements a standardised radiomics workflow. The findings contribute novel insights by establishing PRF as an independent source of diagnostic information, developing standardised methodology for analysis, identifying specific radiomic signatures of aggressive disease, and creating predictive models that outperform conventional assessment. This work demonstrates that non-invasive analysis of PRF can enhance risk stratification and treatment planning in upper urinary tract cancers.24 0Item Restricted PREDICTORS OF HEALTH-RELATED QUALITY OF LIFE AFTER LUNG CANCER SURGERY(University of Birmingham, 2024) Algaeed, Saffana Khalid; Naidu, Babu; Thickett, DavidGlobally, lung cancer is the leading cause of death. Surgical removal of a primary non-small cell lung cancer (NSCLC) tumour offers a significant chance of cure for those suffering. Additionally, it is anticipated that the introduction of screening programs for lung cancer will result in an increase in survival rates. Therefore, health-related quality of life (HRQOL) following surgery has become an important consideration for these patients. However, a considerable number of lung cancer patients who have undergone surgery have not experienced improvement in their breathing afterwards, a condition that can persist for several months following surgery. Computed Tomography (CT) scans of lung cancer patients often demonstrate concurrent emphysema with low attenuation areas (LAAs), the significance of which is unclear. Moreover, sarcopenia is observed in about half of lung cancer patients and is linked to impaired health outcomes and lower survival rates. Identifying the predictors of postoperative HRQOL decline is vital; however, little information is available regarding the relationship between baseline HRQOL, quantitative computed tomography (QCT) of emphysema, or CT-based body composition with postoperative dyspnoea and global health. This thesis aims to examine the predictors of HRQOL of dyspnoea and global health six months following lung cancer surgery. This is a prospective observational study. The European Organisation for Research and Treatment of Cancer (EORTC QLQ-C30) questionnaire and lung cancer module LC13 were introduced at baseline pre-surgery, eight weeks, and six months after lung surgery. Using the CT scans, lung density measurements using %LAA at thresholds of -950 Hounsfield Units (HU) and -910 HU for the assessment of emphysema were quantified and the cross-sectional area of thoracic and abdominal muscles, specifically pectoralis (PM), erector spinae (ESM), psoas (PSM), and skeletal muscles (SM), were analysed using an open-access software. Univariate and multivariate linear, ordinal and multinational regression analyses were performed to find out the predictive value of preoperative HRQOL and CT scan density measurements. Comparative analyses, as well as intra-class correlation coefficients and Bland Altman plots, have also been employed. A total of 1064 patients were recruited over 10 years, and 906 consented patients were included in the study. A significant increase in dyspnoea scores was observed beyond the minimal clinical difference, with values at baseline, eight weeks, and six months were 20.5 ± 22.6, 39.6 ± 24.5, and 33.2 ± 24.7, respectively. In an eight-week period, global health scores dropped from 73.2 ± 20.5 to 63.3 ± 20.5, with only a minimal improvement observed at six months (66.6 ± 22.2). In the multivariate regression analyses, we have demonstrated that baseline dyspnoea is a strong predictor for patients’ postoperative HRQOL after lung cancer surgery (OR = 3.07 – 12.3, p = 0.00). Additionally, baseline global health significantly predicts postoperative HRQOL (coefficient = 0.45 – 0.5, p = 0.00). The data demonstrate that %LAA-950 is a significant predictor of postoperative dyspnoea and global health (OR = 1.2-1.3, p = 0.00), while %LAA-910 is not consistently a strong predictor after adjusting for clinical and perioperative factors. AI-based and semi-automated software showed strong consistency in measuring %LAA-950 and whole lung volume, 15th percentile, and mean lung density. However, there was a lower degree of agreement between the two programs in lobar measurements. Finally, no statistically significant differences were observed in the changes in HRQOL following lung surgery among the small number of patients with sarcopenia10 0