Evaluation Of Image Enhancement Using Different Protocols For Routine Thorax Computed Tomography Examination On 16-Slice Scanners In Two Tertiary Hospitals
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Date
2021-05
Authors
Ibrahim, Noor Ruhaya
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Publisher
Universiti Sains Malaysia
Abstract
The purposes of this study were to evaluate and compare the degree of contrast enhancement and image quality of routine thorax computed tomography (CT) examination on 16-slice scanner in two hospitals using two different protocols. The two protocols named as; 1) automatic bolus tracking (ABT), which volume of contrast media (CM) administered were tailored to the patient weight, known as weight-based volume, (WBV); 2) fixed time delay (FTD) technique, using the same delay for every patient and the patients were administered with fixed volume of contrast media (FV) regardless of their individual variations. Data of 140 patients were collected retrospectively from two centers; 70 patients were examined at Institut Perubatan dan Pergigian Termaju, Universiti Sains Malaysia (IPPT,USM), using ABT with WBV technique, and another 70 patients were examined at Hospital Pulau Pinang, Ministry of Health Malaysia (HPP, MoH) using FTD with FV technique. Patients from IPPT comprises of 19 males and 51 females; mean age ± standard deviation (SD) 53.6 ± 11.2 years; mean weight ± SD 54.04 ± 13.77kg. Patient from HPP comprises of 24 males and 46 females; mean age ± SD 54.5 ± 13.2 years. The degree of contrast enhancement in region of interest (ROI), were measured in Hounsfield unit (HU) values, for quantitative assessment. As for qualitative assessment, CT image were graded on 5 –point scale; 1= very poor, 2 = poor, 3 = fair, 4 = good, and 5 = excellent. The mean enhancement values for patient from HPP were found to be greater than the mean of enhancement values for patient from IPPT (p<0.001). Mean comparison of qualitative scores on a 5-point scale showed no statistical significant difference (p = 0.185). Total contrast media volume and HU values were found to correlate positively, but weak, (r = 0.1619). Overall, FTD with FV protocol yields higher degree of contrast enhancement for routine thorax CT examination. Qualitative assessment showed no statistical significant difference between protocols although CT images taken in ABT with WBV technique were graded higher by assessors than FTD with FV technique. A lot of previous studies preferred ABT with WBV as it produce better result in terms contrast enhancement and improve subjective image quality. To conclude, the optimal scanning technique and CM administration contrast for 16-slice routine thorax CT is ABT with WBV as it can be individualised in order to achieve comparable and satisfactory image enhancement and image quality. It is important to take into account of multiple inter related factors that affect the degree of contrast enhancement and image quality. Each CM administration technique and their validity in clinical practice should be studied further.
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Tecnology