Does dual-energy abdominal computed tomography increase the radiation dose to patients : a prospective observational study

Purpose: The aim of our study was to compare single-energy (SECT) and dual-energy (DECT) abdominal computed tomography (CT) examinations in matched patient cohorts regarding the differences in effective radiation dose (ERD) and image quality performed in a third-generation dual-source computed tomography (DSCT) scanner. Material and methods: Our study included 100 patients, who were divided randomly into 2 groups. The patients included in Group A were scanned by SECT, and Group B members were scanned by DECT. Volume CT dose index (CTDIvol), dose length product (DLP), and ERD for venous phase acquisition were recorded in each patient and were normalised for 40 cm. Analyses were performed by using statistical software (SPSS version 20.0 for windows), and Bonferroni correction for multiple comparisons was applied for p-values and confidence intervals. Results: Average ERD based on DLP values normalised for 40 cm acquisition were obtained for both Group A and Group B. The mean ERD for Group A was 11.89 mSv, and for group B it was 6.87 mSv. There was a significant difference in these values between Group A and Group B as shown by a p-value of < 0.001. On subjective and objective analysis, there was no statistically significant difference in image quality between the 2 groups. Conclusions: The protocols in third-generation DSCT using dual-energy mode resulted in significant reductions in the effective radiation dose (by approximately 58%) compared to SECT in routine abdominal examination in matched cohorts. Therefore, the quantitative imaging potential of DECT can be utilised in needed patients with decreased radiation dose in third-generation DSCT

Comparison of T2 relaxometry and PET CT in the evaluation of patients with mesial temporal lobe epilepsy using video EEG as the reference standard

Purpose: Our study aimed to compare the sensitivity of T2 relaxometry and positron emission tomography - computed tomography (PET/CT) in patients with a history suggestive of mesial temporal lobe epilepsy using video electroencephalography (EEG) as the reference standard. Material and methods: In our study, 35 patients with a history suggestive of mesial temporal lobe epilepsy were subjected to conventional magnetic resonance imaging (MRI), T2 relaxometry, and PET/CT. The results of each of the studies were compared with video EEG findings. Analyses were performed by using statistical software (SPSS version 20.0 for windows), and the sensitivity of conventional MRI, T2 relaxometry, and PET/CT were calculated. Results: The sensitivity of qualitative MRI (atrophy and T2 hyperintensity), quantitative MRI (T2 relaxometry), and PET/CT in lateralizing the seizure focus were 68.6% (n = 24), 85.7% (n = 30), and 88.6% (n = 31), respectively. Conclusions: The sensitivity of MRI in lateralization and localization of seizure focus in temporal lobe epilepsy can be increased by adding the quantitative parameter (T2 relaxometry) with the conventional sequences. T2 Relaxometry is comparable to PET/CT for localization and lateralization of seizure focus and is a useful tool in the workup of TLE patients

Accuracy of Evaluation of Fatty Liver with Third-Generation Unenhanced Dual-Energy CT and MRI: Prospective Comparison with MR Spectroscopy

Background and Objectives The purpose of this study is to evaluate and establish the accuracy of noninvasive methods, including third-generation dual-source dual-energy computed tomography (DECT) and proton density fat (PDF) fraction on magnetic resonance imaging (MRI) using three-dimensional multiecho multipoint chemical shift-encoded spoiled gradient echo (q-Dixon) sequence in the quantification of hepatic steatosis; with H1-MR spectroscopy (MRS) as the reference standard. Materials and Methods A total of 47 patients were included in this prospective study. We studied the accuracy of fatty liver detection using third-generation DECT using mixed set images (MSIs), virtual monochromatic images (VMIs), and MRI q-Dixon. The results were compared with H1-MRS. Data were analyzed using linear regression for each technique compared with MRS. Results Our study's correlation and linear regression analysis showed a good correlation between PDF values obtained by H1-MRS and MR q-Dixon methods (r = 0.821, r 2 = 0.674, p < 0.001). On MSI, H1-MRS showed a low correlation with average liver attenuation (r 2 = 0.379, p < 0.001) and a moderate correlation with liver attenuation index (r 2 = 0.508, p < 0.001) noted. There was a moderate correlation between H1-MRS and average liver attenuation and liver attenuation index on VMI at 80 to 120 keV with r 2 = 0.434, p < 0.001, and r 2 = 0.485, p < 0.001, respectively. Conclusion MRI q-Dixon is the method of choice for evaluating fat quantification in the absence of H1 MRS. Among DECT images, VMI is valuable in the evaluation of hepatic fat as compared with the mixed set of images

Comparison between Conventional Unenhanced and Virtual Unenhanced Imaging of Hepatopancreaticobiliary System with Third-Generation Dual-Source Dual-Energy CT—An Observational Study

Objectives The aims of our study were to assess the comparability of conventional unenhanced images (CUIs) of hepatopancreaticobiliary system with virtual unenhanced images (VUIs) derived from arterial and portal venous phases acquired in a third-generation, dual-source, dual-energy CT (DECT), and also to assess the best dataset among these VUIs. We also calculated the radiation effective dose (ED) reduction by eliminating noncontrast acquisition. Materials and Methods 60 patients were included in our study. Unenhanced images in single energy and contrast-enhanced images in dual-energy mode were acquired. Arterial virtual unenhanced (AVU) and portal virtual unenhanced (PVU) images were generated and compared with CUI, using both objective and subjective methods. The ED was calculated separately for each phase. Statistical significance between difference in mean attenuation values were analyzed using ANOVA and unpaired student t-test. Results In our study, the difference in mean attenuation of liver, spleen, and pancreas between the three phases—CU, AVU, and PVU—were insignificant with p-value > 0.05. This indicates that the values were comparable. Among the VUI, AVU images were statistically superior in image quality. Elimination of noncontrast CT from triple phase abdominal imaging can achieve an average ED reduction of 39%. Conclusions We conclude that VUI generated in third-generation, dual-source DECT has diagnostic image quality and can replace the CUI in triple-phase studies, with a mean ED reduction by 39%. The VUI obtained from arterial phase is superior to those obtained from portal venous phase