Image quality and dosimetry of a dual source computed tomography scanner with special emphasis on radiation dose of lung in a chest examination

The purpose of the current study was to evaluate the Dual Source Computed Tomography scanner in terms of Image quality and dosimetry with special emphasis of radiation dose of lung in a Chest examination.Zielsetzung der Studie war die Evaluation eines Dual-Source-Computertomographen hinsichtlich Bildqualität und Dosimetrie mit speziellem Fokus auf der Lungendosis in Thoraxuntersuchungen

Low kilovoltage computed tomography to reduce contrast medium dose in patients at risk of acute kidney injury

Background: Patients with reduced renal function may be at risk of contrast medium-induced acute kidney injury (CI-AKI) following intravenous iodine contrast medium (CM) enhanced computed tomography (CT). Reducing the CM dose may reduce this risk. Decreasing the X-ray tube potential (kilovoltage, kV) from commonly used 120 to 80 kV results in higher CM attenuation due to the photoelectric properties of iodine, which may permit reduction of the iodine dose while keeping the attenuation unchanged. Lower tube potential, however, increases image noise which may be controlled by increasing the X-ray tube loading (milliampere seconds, mAs) to keep image quality, e.g. contrast-to-noise ratio (CNR) unchanged. Complete compensation of tube loading increases the radiation dose to the patient, but the introduction of noise reducing iterative reconstruction algorithms may prevent this. Aim: To investigate if low-kV CT with reduced CM doses is a feasible alternative in examinations of the thorax and abdomen in patients considered at risk of CI-AKI. Material and methods: In three cross-sectional studies 80-kV CT protocols with 40-50% reduction of CM dose and increased tube loading to control image noise was compared with standard 120-kV protocols, in two studies to diagnose pulmonary embolism and in one hepatic study. Based on a phantom study and a clinical hepatic CT study, iterative reconstruction algorithms were used to control image noise with no increase in tube loading. Image quality was evaluated objectively and subjectively. Results: Using 80-kV CT protocols with reduced CM doses (40-50%) and mAs compensation seems to provide satisfactory diagnostic quality in pulmonary CT angiography and hepatic CT for patients with GFR <45-50 mL/min and a body mass index <30 kg/m2. However, the use of iterative reconstruction algorithms to control image noise without increased mAs resulted in inferior subjective image quality. Conclusion: Using low-kV CT protocols with reduced CM dose could benefit patients at risk of CI-AKI. The usefulness of iterative reconstruction algorithms to control image noise and not increase radiation dose remains unclear

Optimization of CT scanning protocol of Type B aortic dissection follow-up through 3D printed model

This research aims to develop and evaluate a human tissue-like material 3D printed model used as a phantom in determining optimized scanning parameters to reduce the radiation dose for Type B aortic dissection patients after thoracic endovascular aortic repair. The results show that radiation risk for follow-up Type B aortic dissection patients can be potentially reduced. Further, the value of using 3D printed model in studying CT scanning protocols was further validated

Radiation Dose Reduction via Sinogram Affirmed Iterative Reconstruction and Automatic Tube Voltage Modulation (CARE kV) in Abdominal CT

OBJECTIVE: To evaluate the feasibility of sinogram-affirmed iterative reconstruction (SAFIRE) and automated kV modulation (CARE kV) in reducing radiation dose without increasing image noise for abdominal CT examination. MATERIALS AND METHODS: This retrospective study included 77 patients who received CT imaging with an application of CARE kV with or without SAFIRE and who had comparable previous CT images obtained without CARE kV or SAFIRE, using the standard dose (i.e., reference mAs of 240) on an identical CT scanner and reconstructed with filtered back projection (FBP) within 1 year. Patients were divided into two groups: group A (33 patients, CT scanned with CARE kV); and group B (44 patients, scanned after reducing the reference mAs from 240 to 170 and applying both CARE kV and SAFIRE). CT number, image noise for four organs and radiation dose were compared among the two groups. RESULTS: Image noise increased after CARE kV application (p < 0.001) and significantly decreased as SAFIRE strength increased (p < 0.001). Image noise with reduced-mAs scan (170 mAs) in group B became similar to that of standard-dose FBP images after applying CARE kV and SAFIRE strengths of 3 or 4 when measured in the aorta, liver or muscle (p ≥ 0.108). Effective doses decreased by 19.4% and 41.3% for groups A and B, respectively (all, p < 0.001) after application of CARE kV with or without SAFIRE. CONCLUSION: Combining CARE kV, reduction of mAs from 240 to 170 mAs and noise reduction by applying SAFIRE strength 3 or 4 reduced the radiation dose by 41.3% without increasing image noise compared with the standard-dose FBP images.ope

CT Scanning

Since its introduction in 1972, X-ray computed tomography (CT) has evolved into an essential diagnostic imaging tool for a continually increasing variety of clinical applications. The goal of this book was not simply to summarize currently available CT imaging techniques but also to provide clinical perspectives, advances in hybrid technologies, new applications other than medicine and an outlook on future developments. Major experts in this growing field contributed to this book, which is geared to radiologists, orthopedic surgeons, engineers, and clinical and basic researchers. We believe that CT scanning is an effective and essential tools in treatment planning, basic understanding of physiology, and and tackling the ever-increasing challenge of diagnosis in our society

Non-alcoholic fatty liver disease in metabolic syndrome patients in Serdang Hospital: quantification by contrast-enhanced computed tomography

Introduction: Non-alcoholic Fatty Liver Disease (NAFLD) is one of the end organ damage detected in patients having metabolic syndrome X and it can lead to chronic liver failure. Therefore, it is important to be able to assess the condition in a quantifiable manner to help clinicians recognize and treat this disease. Objective: We aimed to determine the prevalence of NAFLD in patients with metabolic syndrome in Serdang Hospital, Malaysia using contrast-enhanced multidetector computed tomography (CECT) abdominal scan. The study also aimed to calculate the quantification of NAFLD using liver to spleen density CT Hounsfield Unit ratio, CTL/S or CTL/S measurement using abdominal CECT scans. Furthermore, we aimed to verify the correlation of dyslipidemia with NAFLD based on the CTL/S parameter. Materials and Method: We conducted a cross-sectional retrospective study in Hospital Serdang, Malaysia using data from January 2012 to December 2013. The sample size was 279 patients with metabolic syndrome who had undergone CECT abdominal scan. Patient demographics were descriptively analysed. Spearman’s correlation test was used to look for association among lipid profile, blood sugar level and CTL/S ratio. Results: The prevalence of NAFLD in metabolic syndrome patients in our population was 82.8%. Prevalence of NAFLD was high among the elderly population (≥ 57 years old). Additionally, Indian ethnics with metabolic syndrome had the highest risk of developing NAFLD (90.9%). There was a significant association between elevated LDL levels and CTL/S ratio (p<0.05); indicative of severity of NAFLD in metabolic syndrome patients. Conclusion: Contrast-enhanced CT scan can help to non-invasively detect and quantify the severity of non-alcoholic fatty liver disease using the CTL/S ratio in patients with metabolic syndrome who are referred for the scan for certain clinical indications. However, we do not recommend it as a stand-alone, first line investigation in the management of NAFLD in metabolic syndrome patients

Focal Spot, Winter 2006/2007

https://digitalcommons.wustl.edu/focal_spot_archives/1104/thumbnail.jp

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