Radiation doses and associated risks from x-ray guided cardiac catheterization procedures in children and young adults

PhD ThesisCardiac catheterizations are an essential procedure in the management of patients with congenital and acquired heart conditions. However, associated radiation doses are often high, raising concerns over potentially increased cancer risks. Neither the radiation doses, nor the associated risks, have been adequately investigated in young people undergoing these procedures. A cohort was established of around 13,500 patients aged under 22 years who have undergone cardiac catheterizations in England. Organ doses were estimated based on a dosimetry system utilising data from Monte Carlo simulations. Doses were highest for the lungs (median: 17.6 millisieverts, mSv) and heart (13.6 mSv), while doses to bone marrow (2.6 mSv) and the thyroid (0.7 mSv) were relatively low. Radiation doses have fallen by a factor of up to ten during the study period. The results were compared to equivalent figures derived from physical measurements. Uncertainties in dose estimates were calculated. These were around ±30%, though were potentially much higher for breast dose. The risk of cancer in relation to estimated doses was calculated using BEIR VII risk models. For examinations conducted using modern equipment, these risks are around 1 in 1700. A small epidemiological analysis was performed, suggesting a nearly threefold increased risk of cancer in the cohort, compared to the general UK population. There are a number of reasons to suggest that this increase was primarily not related to radiation exposure, most notably the large impact of transplantation and likely associated immunosuppressant use. Despite the high cancer incidence, the overall survival in the cohort was high, at around 91% after 30 years. Conclusion: The study provides the first large scale estimation of organ doses from cardiac catheterizations among this age group. Rates of cancer among this patient group are high, although this is appears to be mostly due to factors other than radiation exposure.British Heart Foundatio

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

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

Evaluation of the region-specific risks of accidental radioactive releases from the European Spallation Source

The European Spallation Source (ESS) is a neutron research facility under construction in southern Sweden. The facility will produce a wide range ofradionuclides that could be released into the environment. Some radionuclides are of particular concern such as the rare earth gadolinium-148. In this article, the local environment was investigated in terms of food production and rare earth element concentration in soil. The collected data will later be used to model thetransfer of radioactive contaminations from the ESS

Pathobiology of healing response after endovascular treatment of intracranial aneurysms : Paradigm shift from lumen to wall oriented therapy

Background and Purpose: Subarachnoid hemorrhage attributable to saccular intracranial aneurysm (IA) rupture is a devastating disease leading to stroke, permanent neurological damage and death. Despite rapid advances in the development of endovascular treatment (EVT), complete and long lasting IA occlusion remains a challenge, especially in complexly shaped and large-sized aneurysms. Intraluminal thrombus induced by EVT may recanalize. The biological mechanisms predisposing IA to recanalize and grow are not yet fully understood, and the role of mural cell loss in these processes remains unclear. To elucidate these processes, animal models featuring complex aneurysm architecture and aneurysm models with different wall conditions (such as mural cell loss) are needed. Materials and Methods: Complex bilobular, bisaccular and broad-neck venous pouch aneurysms were microsurgically formed at artificially created bifurcations of both common carotid arteries in New Zealand rabbits. Sidewall aneurysms were microsurgically created on the abdominal aorta in Wistar rats. Some sidewall aneurysms were decellularized with sodium dodecyl sulfate. Thrombosis was induced using direct injection of a fibrin polymer into the aneurysm. CM-Dil-labeled syngeneic smooth muscle cells were injected into fibrin embolized aneurysms. The procedures were followed up with two-dimensional intra-arterial digital subtraction angiography, contrast-enhanced serial magnetic resonance angiographies, endoscopy, optical projection tomography, histology and immunohistochemistry. Results: Aneurysm and parent vessel patency of large aneurysms with complex angioarchitecture was 90% at one month and 86% at one year follow-up in the bifurcation rabbit model. Perioperative and one month postoperative mortality and morbidity were 0% and 9%. Mean operation time in the rat model was less than one hour and aneurysm dimensions proved to be highly standardized. Significant growth, dilatation or rupture of the experimental aneurysms was not observed, with a high overall patency rate of 86% at three week follow-up. Combined surgery-related mortality and morbidity was 9%. Decellularized aneurysms demonstrated a heterogeneous pattern of thrombosis, thrombus recanalization and growth, with ruptures in the sidewall rat model. Aneurysms with intraluminal local cell replacement at the time of thrombosis developed better neointima, showed less recurrence or growth and no ruptures. Growing and ruptured aneurysms demonstrated marked adventitial fibrosis and inflammation, complete wall disruption and increased neutrophil accumulation in unorganized luminal thrombus. Conclusions: Creation of complex venous pouch bifurcation aneurysms in the rabbit is feasible, with low morbidity, mortality and high short-term and long-term aneurysm patency. They represent a promising approach for in vivo animal testing of novel endovascular therapies. The sidewall aneurysm rat model is a quick and consistent method to create standardized aneurysms. Aneurysms missing mural cells are incapable of organizing a luminal thrombus, leading to aneurysm recanalization and increased inflammatory reactions. These, in turn, result in severe wall degeneration, aneurysm growth and eventual rupture. The results of the presented studies suggest that the biologically active luminal thrombus drives the healing process towards destructive wall remodeling and aneurysm rupture. Local smooth muscle cell transplantation compensates for mural cell loss and reduces recurrence, growth and rupture rate in a sidewall aneurysm rat model.Aivovaltimopullistuman repeämisestä johtuva lukinkalvonalinen verenvuoto (subaraknoidaalivuoto, SAV) on äkillinen ja raju kallonsisäinen verenvuoto joka tapahtuu noin tuhannelle henkilölle suomessa per vuosi. SAV aiheuttaa pysyvän neurologisen haitan tai kuoleman valtaosalle potilaista. Aivovaltimopullistumia voidaan hoitaa joko mikrokirurgisella leikkauksella tai tukkimalla pullistuma suonensisäisesti (endovaskulaarinen hoito). Suonesisäiset hoitomenetelmät ovat viime vuosikymmeninä kehittyneet merkittävästi, mutta edelleen osaa pullistumista ei voida tällä menetelmällä hoitaa ja ajoittain hoidon tulos ei ole pitkällä aikavälillä pysyvä. Suonensisäisten hoitomenetelmien jatkokehittämiseksi tarvitaan enemmän tietoa aivovaltimopullistuman seinämässä tapahtuvista biologisista mekanismeista ja realistisempiä kokeellisia malleja, mukaan lukien koe-eläinmalleja, joissa hoitomenetelmiä voidaan testata. Tässä väitöskirjassa on syvennytty tutkimaan kahta eri koe-eläinmallia, kani- ja rottamallia. Väitöskirjassa osoitetaan että mallit soveltuvat suonensisäisten hoitomenetelmien testaamiseen. Malleissa on kyetty realistisella tavalla mallintamaan todellisen aivovaltimopullistuman eri rappeutuneisuusasteita ja saatu merkittävää lisätietoa siitä miten pullistuman seinämän biologiset tapahtumat joko vahvistavat seinämää tai altistavat seinämän repeämiselle