8 3. CT IMAGING 3.1. Best single slice to measure visceral adipose tissue in children Presenter: Michelle O’Connor, University College Dublin, Ireland Authors: Michelle O'Connor, John Ryan, Shane Foley Introduction: Childhood obesity has reached epidemic proportions in Europe. It is now the most prevalent childhood disease. The World Health Organization estimated that over 42 million children worldwide were overweight in 2010. Abdominal obesity is highly prevalent in children. Abdominal adipose tissue can be characterized as subcutaneous or visceral adipose tissue based on its location in the abdomen. Visceral adipose tissue surrounds internal organs in the abdominal cavity. Excessive visceral adipose tissue (VAT) is a significant risk factor for insulin resistance, metabolic syndrome, cardiovascular disease and diabetes. VAT is related to these medical conditions through blood drainage, hormonal factors, inflammation and adipocytokines. Quantifying VAT in children will have a major impact on the early identification of children at elevated health risk and will aid prioritization of health care resources. While the optimal CT single slice location for measuring VAT has been widely investigated in adults, it has yet to be investigated in children. This study investigates 1) the optimal single CT slice location for predicting total abdominal VAT volume in paediatrics and 2) the relations between anthropometric measurements, gender, age and VAT volume. Methods: A random sample of abdominal CTs was stratified by age and gender. VAT area was measured at each intervertebral level and correlated to total VAT volume. Waist circumference, sagittal diameter, age and gender were evaluated as VAT volume predictors. Results: The mean abdominal VAT volume was highest in females aged 12- 16 years and in males aged 9-12 years. Pubertal weight gain, growth spurts, diet and physical activity level may have attributed to these differences. VAT area at L2-L3 correlated best to overall VAT volume in females and in males 6 years. Regression between WC, SD, age, gender and VAT volume showed that waist circumference was most predictive of VAT volume.(Beta=0.970, p=0.001). 3.2. Role of MDCT In Perfusion Hepatocellular Carcinoma- Newer Technique Presenter: Lalit Kumar Gupta, Post Graduate Institue Of Medical Education And Research, Chandigarh-India Authors: Kalra Naveen, Kartik G., Bansal S.C., Khandelwal N. Introduction: Hepatocellular Carcinoma (HCC) is the most common liver cancer in India. Multi detector Computed tomography (MDCT) with perfusion imaging is a newer application in which a quantitative map of tissue perfusion is created from dynamic data and displayed using a color scale, allowing quantification of perfusion in absolute units at high spatial resolution. A dynamic study of the selected area of liver is performed in a shallow breathing technique. A total of 50 mL of non-ionic iodinated contrast is injected and data is acquired and processed with Body volume perfusion CT (BVPCT) software. Functional maps of BF, TTP, BV, MTT are generated. Methods: The following parameters. KV: 100, mAs: 150, Slice thickness: 1.5mm, No of scan: 20, no. of image: 2440, exam time: 59.48 sec, Delay: 5 sec, Rotation time: 0.285 and delayed is taken after 120 sec after dynamic imaging covering the whole liver Results: The hepatic arterial perfusion of HCC is typically increased with decreased in protocol liver perfusion. HBF and HBV increases in HCC compared to background liver tissue and the MTT is decreased. The MTT of HCC is shorter than that of background liver parenchyma and the degree of MTT reduction is correlated to the grade of the malignancy. CTPI is feasible and noninvasive and reproducible technique for quantifying tumor vascularity and angiogenesis in HCC. 3.3. CT Guided Steroid Injections: An optimized dose approach Presenter: Peter Traise, Hunter New England Imaging (NSW Health), Australia Authors: Peter Traise/ Dr Beng Tan Introduction: The use of CT for a variety of both diagnostic and therapeutic procedures is increasing. This can be attributed to technological advances in CT, which have continued to open potential fields of application (McCullough, C., et al. 2009.) However, studies by Brenner and Hall (2007) and Mathews et.al (2013) conclude that the increase in CT use has significant implications of increased cancer risk, especially in a younger population. Consequently, there has been a greater focus on reducing the CT-induced radiation dose by both vendors and endusers of CT imaging equipment. Methods have been implemented to reduce dose, ranging from equipment-based dose modulation, improved sensitivity of detector materials and more recently by revision of CT image reconstruction algorithms. However, availability of latest CT technology in rural areas of Australia are often hampered by high costs of replacement equipment. Thus, other techniques of reducing dose must be employed to improve patient safety. There is an increasing use of CT for needle guidance in therapeutic paraspinal steroid injections. One simple technique, reducing tube current (mA), shows great promise in optimizing radiation dose whilst maintaining sufficient image quality for these procedures to be performed accurately and safely. Preliminary results from a current study in progress by the author would indicate the potential for dose reductions of 60-80% in CT guided steroid injections with little impact on the image quality of needle-tip visualisation. Methods: Participants were recruited and randomised into two groups, A&B. Group A underwent the procedure with a reduced mA technique; Group B with the standard technique. The dose length product (DLP) was recorded. Images were reviewed for visualisation QA. Results: Reduction of tube current to factory minimum appears to be a potentially useful and simple method of reducing radiation dose in CT guided interventional procedures where high contrast structures are being visualised. Although data gathering is not yet complete, preliminary results indicate that it is possible to reduce successfully CT DLP between 65-88% of the average dose using a low mA technique without significant degradation of image quality. 3.4. Siberian tiger in computed tomography - image quality considerations Presenter: Rikke Bramming, Department of Radiology, Odense University Hospital, Denmark Author: Kristine Skov Hansen, Department of Radiology, Odense University Hospital, Denmark Introduction: The Siberian tiger of Odense Zoo was suffering from lower back problems such as limping and needed a examination. A number of challenges such as size, weight, hygiene and safety precautions had to be considered. The tiger weighed approximately 300kg and was 4 meters long. Because of its lethal canine nature and quarantine limitations the examination had to be carried out at the Department of Forensic Medicine. It was crucial to get a result of the scan because the Siberian tiger is an endangered species and this specific tiger plays an important role in the genetic preservation of the species. Methods: With use of a dual-slice Siemens CT scanner the examination was planned and performed as it went along due to the challenging size and weight. Results: As expected the image quality was far from optimal but it was possible to rule out stenosis of the spinal canal such as a ruptured disc. 3.5. Effectiveness and Acceptability of Newly designed Shoulder Extension Device to improve image quality in Neck CT Presenter: Woong Yong Cho, Asan Medical Center. Radiology, Seoul, Korea Author: Woong Yong Cho Introduction: Deterioration of image quality due to the beam hardening effect caused by the shoulder joints in neck CT images makes it difficult to detect the abnormal lesions and to identify the anatomical structures. Therefore, we tried to improve the image quality of the neck CT by using a shoulder extension device which fully extended the shoulder joints. Methods: Patients who underwent neck CT were divided into 3 groups according to weight; A (80kg<), B(60kg<), and C(40kg). For each group, noise of CT images was assessed at 5th and 6th cervical spine level using. Results:Mean noise values of the CT images using the device were 18.3, 11.4 and 9.7 in group A, B and C, respectively. Mean noise values of the CT images without using the device were 9.8, 7.2 and 4.2in each group. Dose reduction is the largest in group A so that it is more effective in patients who are heavier. In qualitative evaluation, the score was high as 4.7 out of 5. In the survey, patients rated the inconvenience level as low.
ISRRT | Book Of Abstracts
To see the actual publication please follow the link above