scholarly journals Verification of the Dose Reduction Effect via Diluted Injection in Dual-Energy Computed Tomography Using a Human Blood Flow Phantom

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Hironobu Tomita ◽  
Koichi Shibata
Keyword(s):  
Computed Tomography ◽  
Blood Flow ◽  
Contrast Medium ◽  
Energy Method ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Dual Energy ◽  
Mixing Ratio ◽  
Ct Number ◽  
Flow Phantom

Purpose. We sought to examine the possibility of reducing the contrast medium dosage in dual-energy imaging using a saline-mixed injection with a virtual monochromatic energy method of dual-source computed tomography (CT). Methods. An X-ray CT (SOMATOM Definition Flash: Siemens, Nurnberg, Germany) was employed. The mixing ratio of contrast medium and saline was gradually changed by 10%, followed by a mixed injection into a dynamic blood flow phantom (Nemoto Kyorindo, Japan) which is a hemodynamic simulation phantom to obtain time-enhancement curves (TECs). Exactly 64 TECs were prepared for each mixing ratio by changing the energy from 40 to 75 keV for monoenergetic imaging. The relationship between the image standard deviation (SD) and the energy of the virtual monochromatic image was determined. Combinations of the mixing ratio and energy (keV), which can maintain high CT numbers and low image SDs for 3D imaging, were tested, and the reduction rate of the contrast medium was calculated. Results. The TECs for the mixed injection method changed linearly with the dilution rates. The mixing ratios were strongly correlated with the maximum CT number of the TEC (R2 = 0.98). Contrast CT numbers and image SDs increased by approximately 20% and 25%, respectively, as the energy decreased by 5 keV. The optimal conditions for reducing the contrast medium dose were a mixing ratio of 6:4 and 55 keV of energy. Conclusion. The virtual monochromatic energy method reduced the contrast medium dosage by up to 40% for three-dimensional CT-angio (3DCTA) tests.

scholarly journals Time-Enhancement Curve of Four-Dimensional Computed Tomography Predicts Aneurysm Enlargement with Type-II Endoleak after Endovascular Aneurysm Repair

Aorta ◽  
2020 ◽  
Vol 08 (02) ◽  
pp. 029-034
Author(s):  
Yunosuke Nishihara ◽  
Kota Mitsui ◽  
Shinya Azama ◽  
Daisuke Okamoto ◽  
Manabu Sato ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Equilibrium Phase ◽  
Endovascular Aneurysm Repair ◽  
Three Dimensional ◽  
Type Ii ◽  
Ct Scanner ◽  
Stable Group ◽  
Ct Number ◽  
4D Ct ◽  
Aneurysm Repair

Abstract Objective We investigated the hemodynamic features of Type-II endoleaks after endovascular aneurysm repair (EVAR) using four-dimensional (4D) computed tomography (CT) to identify patients with aneurysm enlargement. Methods During a 13-month period (January 2017–January 2018) at our institution, we performed 4D-CT examinations in 13 patients after EVAR because of suspected Type-II endoleaks. Three patients were excluded from the study because of other endoleaks or absence of detectable endoleaks. The ramaining 10 patients were divided into two groups: enlargement group (n = 4), in which the aneurysm volume increased, and stable group (n = 6), in which the aneurysm remained stable or shrank. A CT scanner and three-dimensional workstation were used. All images were obtained using a consistent protocol (22 phase scans using the test bolus tracking method). We analyzed the hemodynamics of the endoleak cavity (EC) relative to those of the aorta and evaluated the time-enhancement curves (TECs) using measurement protocols. The strengths of correlations between these factors in the two groups were analyzed statistically. Results TECs in the enlargement group showed a more gradual curve, and the upslope, the gradient of TEC in the ascending phase and the upslope index were significantly more gradual than those in the stable group (p = 0.0247, 0.0243). The EC washout and the EC washout index were also more gradual than in the stable group's (p = 0.019, 0.019). The enhancement duration was longer in the former than in the latter (80%, p = 0.0195; 70%, p = 0.0159; 60%, p = 0.0159). The CT number in the equilibrium phase was larger in the enlargement group than in the stable group (p = 0.019). Conclusion The 4D-CT is useful for predicting aneurysm enlargement with Type-II endoleaks after EVAR.

scholarly journals Staging of pulmonary metastases using dual-energy computed tomography after anti-angiogenic therapy

2017 ◽  
Vol 4 (2) ◽  
pp. 74
Author(s):  
Jens-Christian Altenbernd ◽  
Axel Wetter ◽  
Lale Umutlu ◽  
Michael Forsting
Keyword(s):  
Computed Tomography ◽  
Contrast Medium ◽  
Pulmonary Metastases ◽  
Small Cell Lung Carcinoma ◽  
Therapy Response ◽  
Dual Energy ◽  
Rank Test ◽  
Time Interval ◽  
Cell Lung Carcinoma ◽  
Dual Energy Computed Tomography

Objective: The aim of this study was the evaluation of dual-energy computed tomography (DECT) for the assessment of pulmonary metastases (PM) after antiangiogentic therapy (AT).Material and methodology: A total of 82 patients with non-small cell lung carcinoma (NSCLC), colorectal cancer (CRC), gastrointestinal stromal tumors (GIST) and hepatocellular carcinoma (HCC) were examined before and after AT with  DECT of the lung. The number, size, CT densities (HU) of the PM were determined by 2 radiologists in consens in both DECT. The Wilcoxon sign rank test was applied (SPSS, version 21, SPSS, IBM, Chicago, USA).Results: The 82 patients (NSCLC: 32/82; CRC: 34/82; GIST: 10/82; HCC: 6/82) with a total of 201 PM were included. DECT were produced with a time interval of 4 $\pm$ 1 months. Size changes of the metastases: PM total 23 mm vs. 24 mm; p = .1/ NSCLC 22 mm vs. 23 mm; p = .2/ CRC 23 mm vs. 23 mm; p = .3/ GIST 24 mm vs. 25 mm; p = .1/ HCC 22 mm vs. 21 mm; p = .1. Contrast media in the course: PM total 45 HU vs. 25 HU; -44%; p < .05/ NSCLC 43 HU vs. 22 HU; -49%; p < .05/CRC 33 HU vs. 15 HU; -55%; p < .05/ GIST 45 HU vs. 24 HU; 47%; p < .05/HCC 62 HU vs. 43 HU; -31%, p < .05.Conclusions: The quantification of the contrast medium uptake of pulmonary metastases is valid by using dual-energy imaging. In this way, the therapy response according to antiangiogenetic therapy with regard to the contrast medium uptake can be assessed more precisely without native imaging in addition to changes in the size of the metastases.

scholarly journals Imaging of Contrast Medium Extravasation in Anticoagulation-Associated Intracerebral Hemorrhage With Dual-Energy Computed Tomography

Stroke ◽  
2013 ◽  
Vol 44 (10) ◽  
pp. 2883-2890 ◽  
Author(s):  
Sae-Yeon Won ◽  
Frieder Schlunk ◽  
Julien Dinkel ◽  
Hulya Karatas ◽  
Wendy Leung ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Intracerebral Hemorrhage ◽  
Contrast Medium ◽  
Dual Energy ◽  
Hematoma Expansion ◽  
Prothrombin Complex Concentrates ◽  
Dual Energy Computed Tomography ◽  
Warfarin Group ◽  
Significant Difference ◽  
Contrast Medium Extravasation

Background and Purpose— Contrast medium extravasation (CE) in intracerebral hemorrhage (ICH) is a marker of ongoing bleeding and a predictor of hematoma expansion. The aims of the study were to establish an ICH model in which CE can be quantified, characterized in ICH during warfarin and dabigatran anticoagulation, and to evaluate effects of prothrombin complex concentrates on CE in warfarin-associated ICH. Methods— CD1-mice were pretreated orally with warfarin, dabigatran, or vehicle. Prothrombin complex concentrates were administered in a subgroup of warfarin-treated mice. ICH was induced by stereotactic injection of collagenase VIIs into the right striatum. Contrast agent (350 μL Isovue 370 mg/mL) was injected intravenously after ICH induction (2–3.5 hours). Thirty minutes later, mice were euthanized, and CE was measured by quantifying the iodine content in the hematoma using dual-energy computed tomography. Results— The optimal time point for contrast injection was found to be 3 hours after ICH induction, allowing detection of both an increase and a decrease of CE using dual-energy computed tomography. CE was higher in the warfarin group compared with the controls ( P =0.002). There was no significant difference in CE between dabigatran-treated mice and controls. CE was higher in the sham-treated warfarin group than in the prothrombin complex concentrates–treated warfarin group ( P <0.001). Conclusions— Dual-energy computed tomography allows quantifying CE, as a marker of ongoing bleeding, in a model of anticoagulation-associated ICH. Dabigatran induces less CE in ICH than warfarin and consequently reduces risks of hematoma expansion. This constitutes a potential safety advantage of dabigatran over warfarin. Nevertheless, in case of warfarin anticoagulation, prothrombin complex concentrates reduce this side effect.

Three-dimensional Fusion Imaging without Contrast Medium for Carotid Endarterectomy

2017 ◽  
Vol 79 (01) ◽  
pp. 073-076
Author(s):  
Tohru Mizutani ◽  
Kenji Sumi ◽  
Katsuyoshi Shimizu ◽  
Masaki Matsumoto
Keyword(s):  
Computed Tomography ◽  
Carotid Artery ◽  
Contrast Medium ◽  
Carotid Endarterectomy ◽  
Carotid Artery Stenosis ◽  
Three Dimensional ◽  
Fusion Imaging ◽  
Artery Stenosis ◽  
3D Computed Tomography ◽  
Fusion Images

AbstractCarotid endarterectomy (CEA) is a popular surgical procedure for patients with carotid artery stenosis. Before performing CEA, radiologic information about carotid artery stenosis must be obtained using three-dimensional (3D) computed tomography angiography (CTA). However, it is difficult to perform 3D-CTA in patients with renal dysfunction and an allergy to contrast medium. To solve this problem, 3D fusion images (3D-FI) with magnetic resonance angiography and 3D computed tomography are created. In this report, we describe the utility of 3D-FI.

scholarly journals Diameter measurements in three-dimensional printed flow phantom model of the carotid artery in preterm infants

2021 ◽  
Vol 8 (6) ◽  
pp. 8-21
Author(s):  
Sujith Pereira ◽  
Jonathan Reeves ◽  
Malcolm Birch ◽  
Ahmed Ali ◽  
Ajay Sinha ◽  
...  
Keyword(s):  
Blood Flow ◽  
Carotid Artery ◽  
Preterm Infants ◽  
Three Dimensional ◽  
Lumen Diameter ◽  
Diameter Measurement ◽  
Phantom Model ◽  
Observer Reliability ◽  
Flow Phantom ◽  
3D Printed

Diameter form an integral part of blood flow measurement. This study aimed to explore different three-dimensional (3D) printed materials to develop flow phantom models of the carotid artery in preterm newborn infants and to investigate ideal diameter measurement points using ultrasound that reflected accurate lumen diameter measurement. Cerebral blood flow measurements data using Doppler ultrasound of the right common carotid artery from 21 randomly selected preterm infants were used to produce a 3D printed Doppler flow phantom model with three different vessel diameters. Diameters were measured by multiple observers blinded to phantom vessel characteristics and each other’s measurements. 9 measurement points were studied. Agreement between observers, inter and intra observer reliability and coefficient of variation (CoV) was examined. Of the 63 diameter measurements, 45 (71%) were performed on flow phantoms with vessel diameter of 0.196 cm. Bland-Altman plots revealed that measurement performed using leading edge to centre (mean bias 1.8% {95%LOA -4.1% to 7.7%}) and centre to trailing edge (mean bias 1.1% {95%LOA -5.4% to 7.8%}) resulted in the most accurate lumen diameter measurements. Inter and intra-observer reliability was excellent. The mean CoV for inter observer measurements was 1.7% and intra observer measurements was 1.6% and 1.8% for each observer. We successfully produced a 3D printed flow phantom model of the carotid artery in preterm infants and identified two measurement methods that result in reliable and accurate lumen diameter measurement. Researchers and clinicians can use this information for further studies involving ultrasound diameter measurements in small calibre vessels.

Sign in / Sign up

Export Citation Format

Share Document