Using Cone Beam Computed Tomography for radiological assessment beyond dento-maxillofacial imaging: a review of the clinical applications in other anatomical districts

Background: Cone Beam Computed Tomography (CBCT) represents the optimal imaging solution for the evaluation of the maxillofacial and dental area when quantitative geometric and volumetric accuracy is necessary (e.g., in implantology and orthodontics). Moreover, in recent years, this technique has given excellent results for the imaging of lower and upper extremities. Therefore, significant interest has been increased in using CBCT to investigate larger and non-traditional anatomical districts. Objective: The purpose of this work is to review the scientific literature in Pubmed and Scopus on CBCT application beyond head districts by paying attention to image quality and radiological doses. Method: The search for keywords was conducted in Pubmed and Scopus databases with no back-date restriction. Papers on applications of CBCT to head were excluded from the present work. From each considered paper, parameters related to image quality and radiological dose were extracted. An overall qualitative evaluation of the results extracted from each issue was done by comparing the conclusive remarks of each author regarding doses and image quality. PRISMA statements were followed during this process. Results: The review retrieved 97 issues from 83 extracted papers; 46 issues presented a comparison between CBCT and Multi-Detector Computed Tomography (MDCT), and 51 reviewed only CBCT. The radiological doses given to the patient with CBCT were considered acceptable in 91% of cases, and the final image quality was found in 99%. Conclusion: CBCT represents a promising technology not only for imaging of the head and upper and lower extremities but for all the orthopedic districts. Moreover, the application of CBCT derived from C-arms (without the possibility of a 360 ° rotation range) during invasive investigations demonstrates the feasibility of this technique for non-standard anatomical areas, from soft tissues to vascular beds, despite the limits due to the incomplete rotation of the tube

Advancements in minimally invasive image-guided liver therapies

This thesis is a contribution to the fight against cancer. It focuses on patients with hepatic malignancies. Interventional oncology (IO) is a rapidly evolving sub-speciality of interventional radiology with an increasing role in the management of cancer patients. Over the past two decades interventional radiologists together with scientists have ridding the tidal wave of technological innovation to introduce multiple novel cancer treatments. IO procedures are minimally invasive, targeted therapies that are associated with low complication rates and short hospital admissions. Such therapies offer clear advantages over surgical procedures and intense chemotherapeutic regimes that put a larger burden on both the health care budget and patients. In this thesis several novel minimally invasive therapies are investigated. PART I focuses on image-guided percutaneous RFA. PART II discusses transarterial liver therapies, such as transarterial chemoembolisation, radioembolisation and percutaneous hepatic perfusion. PART III investigates ways to improve the management of patients that undergo IO procedures.LUMC / Geneeskund

VOXEL-LEVEL ABSORBED DOSE CALCULATIONS WITH A DETERMINISTIC GRID-BASED BOLTZMANN SOLVER FOR NUCLEAR MEDICINE AND THE CLINICAL VALUE OF VOXEL-LEVEL CALCULATIONS

Voxel-level absorbed dose (VLAD) is rarely calculated for nuclear medicine (NM) procedures involving unsealed sources or 90Y microspheres (YM). The current standard of practice for absorbed dose calculations in NM utilizes MIRD S-values, which 1) assume a uniform distribution in organs, 2) do not use patient specific geometry, and 3) lack a tumor model. VLADs overcome these limitations. One reason VLADs are not routinely performed is the difficulty in obtaining accurate absorbed doses in a clinically acceptable time. The deterministic grid-based Boltzmann solver (GBBS) was recently applied to radiation oncology where it was reported as fast and accurate for both megavoltage photons and high dose rate nuclide-based photon brachytherapy. This dissertation had two goals. The first was to demonstrate that the general GBBS code ATTILA™ can be used for VLADs in NM, where primary photon and electron sources are distributed throughout a patient. The GBBS was evaluated in voxel-S-value geometries where agreement with Monte Carlo (MC) in the source voxel was 6% for 90Y and 131I; 20% differences were seen for mono-energetic 10 keV photons in bone. An adaptive tetrahedral mesh (ATM) generation procedure was developed using information from both the SPECT and CT for 90Y and 131I patients. The ATM with increased energy transport cutoffs, enabled GBBS transport to execute in under 2 (90Y) and 10 minutes (131I). GBBS absorbed doses to tumors and organs were within 4.5% of MC. Dose volume histograms were indistinguishable from MC. The second goal was to demonstrate VLAD value using 21 YM patients. Package insert dosimetry was not able to predict mean VLAD tumor absorbed doses. Partition model had large bias (factor of 0.39) and uncertainty (±128 Gy). Dose-response curves for hepatocellular carcinoma tumors were generated using logistic regression. The dose covering 70% of volume (D70) predicted binary modified RECIST response with an area under the curve of 80.3%. A D70 88 Gy threshold yielded 89% specificity and 69% sensitivity. The GBBS was shown to be fast and accurate, flaws in clinical dosimetry models were highlighted, and dose-response curves were generated. The findings in this dissertation support the adoption of VLADs in NM

Characterization of alar ligament on 3.0T MRI: a cross-sectional study in IIUM Medical Centre, Kuantan

INTRODUCTION: The main purpose of the study is to compare the normal anatomy of alar ligament on MRI between male and female. The specific objectives are to assess the prevalence of alar ligament visualized on MRI, to describe its characteristics in term of its course, shape and signal homogeneity and to find differences in alar ligament signal intensity between male and female. This study also aims to determine the association between the heights of respondents with alar ligament signal intensity and dimensions. MATERIALS & METHODS: 50 healthy volunteers were studied on 3.0T MR scanner Siemens Magnetom Spectra using 2-mm proton density, T2 and fat-suppression sequences. Alar ligament is depicted in 3 planes and the visualization and variability of the ligament courses, shapes and signal intensity characteristics were determined. The alar ligament dimensions were also measured. RESULTS: Alar ligament was best depicted in coronal plane, followed by sagittal and axial planes. The orientations were laterally ascending in most of the subjects (60%), predominantly oval in shaped (54%) and 67% showed inhomogenous signal. No significant difference of alar ligament signal intensity between male and female respondents. No significant association was found between the heights of the respondents with alar ligament signal intensity and dimensions. CONCLUSION: Employing a 3.0T MR scanner, the alar ligament is best portrayed on coronal plane, followed by sagittal and axial planes. However, tremendous variability of alar ligament as depicted in our data shows that caution needs to be exercised when evaluating alar ligament, especially during circumstances of injury

Case series of breast fillers and how things may go wrong: radiology point of view

INTRODUCTION: Breast augmentation is a procedure opted by women to overcome sagging breast due to breastfeeding or aging as well as small breast size. Recent years have shown the emergence of a variety of injectable materials on market as breast fillers. These injectable breast fillers have swiftly gained popularity among women, considering the minimal invasiveness of the procedure, nullifying the need for terrifying surgery. Little do they know that the procedure may pose detrimental complications, while visualization of breast parenchyma infiltrated by these fillers is also deemed substandard; posing diagnostic challenges. We present a case series of three patients with prior history of hyaluronic acid and collagen breast injections. REPORT: The first patient is a 37-year-old lady who presented to casualty with worsening shortness of breath, non-productive cough, central chest pain; associated with fever and chills for 2-weeks duration. The second patient is a 34-year-old lady who complained of cough, fever and haemoptysis; associated with shortness of breath for 1-week duration. CT in these cases revealed non thrombotic wedge-shaped peripheral air-space densities. The third patient is a 37‐year‐old female with right breast pain, swelling and redness for 2- weeks duration. Previous collagen breast injection performed 1 year ago had impeded sonographic visualization of the breast parenchyma. MRI breasts showed multiple non- enhancing round and oval shaped lesions exhibiting fat intensity. CONCLUSION: Radiologists should be familiar with the potential risks and hazards as well as limitations of imaging posed by breast fillers such that MRI is required as problem-solving tool