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Virtual monoenergetic

Tonghe Wang, Beth Bradshaw Ghavidel, Jonathan J Beitler, Xiangyang Tang, Yang Lei, Walter J Curran, Tian Liu, Xiaofeng Yang
PURPOSE: Dual-energy computed tomography (DECT) using TwinBeam CT (TBCT) is a new option for radiation oncology simulators. TBCT scanning provides virtual monoenergetic images which are attractive in treatment planning since lower energies offer better contrast for soft tissues, and higher energies reduce noise. A protocol is needed to achieve optimal performance of this feature. In this study, we investigated the TBCT scan schema with the head-and-neck radiotherapy workflow at our clinic and selected the optimal energy with best contrast-noise-ratio (CNR) in organs-at-risks (OARs) delineation for head-and-neck treatment planning...
January 28, 2019: Journal of Applied Clinical Medical Physics
Victor Neuhaus, Nils Grosse Hokamp, David Zopfs, Kai Laukamp, Simon Lennartz, Nuran Abdullayev, David Maintz, Jan Borggrefe
PURPOSE: To evaluate the reduction of artifacts caused by total hip replacements (THR) in dual-layer DECT (DLCT) provided by the combination of virtual monoenergetic images (VMI) and orthopedic metal artifact reduction (MAR). MATERIALS AND METHODS: A total of 24 consecutive patients carrying THR, who received DLCT, were included. Four different images were reconstructed from the same CT dataset: a) conventional images (CI), b) conventional images with orthopedic metal artifact reduction (CIMAR ) c) VMI and d) VMI combined with orthopedic metal artifact reduction (VMIMAR )...
February 2019: European Journal of Radiology
Taek Min Kim, Young Hun Choi, Jung Eun Cheon, Woo Sun Kim, In One Kim, Ji Eun Park, Su Mi Shin, Seong Yong Pak, Bernhard Krauss
OBJECTIVE: To compare quantitative and qualitative image quality parameters in pediatric abdominopelvic dual-energy CT (DECT) using noise-optimized virtual monoenergetic image (VMI) and conventional VMI at different kiloelectron volt (keV) levels. MATERIALS AND METHODS: Thirty-six consecutive abdominopelvic DECT scans were retrospectively included. Noise-optimized VMI and conventional VMI were reconstructed at seven energy levels, from 40 keV to 100 keV at 10 keV intervals...
February 2019: Korean Journal of Radiology: Official Journal of the Korean Radiological Society
Hsu-Cheng Huang, Ramya Srinivasan, Yuxin Sun, Galateia J Kazakia, Pei-Chen Lin, Benjamin M Yeh
OBJECTIVE: The purpose of this study was to evaluate the sensitivity, tumor conspicuity, and image quality of different material decomposition images of phantoms and patients with nearly isodense bone metastases using rapid-kilovoltage-switching dual-energy CT (DECT). MATERIALS AND METHODS: Fifty-one semianthropomorphic lumbar spine phantoms embedded with 75 simulated tumors were scanned without and with outer torso-attenuating encasement under the same scan settings...
February 2019: AJR. American Journal of Roentgenology
Elias Kikano, Nils Grosse Hokamp, Leslie Ciancibello, Nikhil Ramaiya, Christos Kosmas, Amit Gupta
BACKGROUND: One of the key steps in generating three-dimensional (3D) printed models in medicine is segmentation of radiologic imaging. The software tools used for segmentation may be automated, semi-automated, or manual which rely on differences in material density, attenuation characteristics, and/or advanced software algorithms. Spectral Detector Computed Tomography (SDCT) is a form of dual energy computed tomography that works at the detector level to generate virtual monoenergetic images (VMI) at different energies/ kilo-electron volts (keV)...
January 18, 2019: 3D printing in medicine
Kai Roman Laukamp, David Zopfs, Simon Lennartz, Lenhard Pennig, David Maintz, Jan Borggrefe, Nils Große Hokamp
OBJECTIVES: This study compares reduction of strong metal artifacts from large dental implants/bridges using spectral detector CT-derived virtual monoenergetic images (VMI), metal artifact reduction algorithms/reconstructions (MAR), and a combination of both methods (VMIMAR ) to conventional CT images (CI). METHODS: Forty-one spectral detector CT (SDCT) datasets of patients that obtained additional MAR reconstructions due to strongest artifacts from large oral implants were included...
January 16, 2019: European Radiology
Simon Lennartz, Markus Le Blanc, David Zopfs, Nils Große Hokamp, Nuran Abdullayev, Kai Roman Laukamp, Stefan Haneder, Jan Borggrefe, David Maintz, Thorsten Persigehl
Purpose To evaluate the use of spectral CT for differentiation between noncalcified benign pleural lesions and pleural carcinomatosis. Materials and Methods In this retrospective study, patients who underwent contrast agent-enhanced late venous phase spectral CT of the chest between June 1, 2016, and July 1, 2018 with histopathologic and/or imaging confirmation of noncalcified pleural lesions were evaluated. Conventional images, iodine overlay (IO) images, and virtual monoenergetic images at 40 keV (hereafter, VMI40keV ) were reconstructed from contrast-enhanced spectral chest CT...
January 15, 2019: Radiology
N Große Hokamp, V C Obmann, R Kessner, K R Laukamp, T Persigehl, S Haneder, N Ramaiya
OBJECTIVES: The well-known boost of iodine associated-attenuation in low-keV virtual monoenergetic images (VMI_low) is frequently used to improve visualization of lesions and structures taking up contrast media. This study aimed to evaluate this concept in reverse. Hence to investigate if increased attenuation within the liver allows for improved visualization of little or not-enhancing lesions. METHODS: A 3D-printed phantom mimicking the shape of a human liver exhibiting a lesion in its center was designed and printed...
December 2018: European Journal of Radiology
Rolf Symons, Yves De Bruecker, John Roosen, Laurent Van Camp, Tyler E Cork, Steffen Kappler, Stefan Ulzheimer, Veit Sandfort, David A Bluemke, Amir Pourmorteza
PURPOSE: To evaluate the performance and clinical feasibility of 0.25 mm resolution mode of a dual-energy photon-counting detector (PCD) computed tomography (CT) system for coronary stent imaging and to compare the results to state-of-the-art dual-energy energy-integrating detector (EID) CT. MATERIALS AND METHODS: Coronary stents with different diameters (2.0-4.0 mm) were examined inside a coronary artery phantom consisting of plastic tubes filled with iodine-based and gadolinium-based contrast material diluted to approximate clinical concentrations (n = 18)...
November 2018: Journal of Cardiovascular Computed Tomography
Qin Zong Gao, Zhi Wei Wang, Ya Fei Qi, Zheng Yu Jin
Objective To evaluate the value of virtual monoenergetic(monoE)using dual-layer detector spectrum CT in detecting small lesions in rabbit VX2 liver cancer models.Methods Hepatic VX2 double tumor models were established in 24 New Zealand white rabbits by CT-guided puncture. All the rabbits underwent CT scans by using dual-layer detector CT to generate conventional 120-keV polychromatic images and monoE images with energy levels ranging from 40 to 100 keV during the arterial phase. The quantity of the lesion and measurement of the lesion length as well as the objective evaluations[signal noise ratio(SNR)and contrast noise ratio(CNR)] and the subjective evaluations(overall image quality score)of the image quality were independently measured by two radiologists...
October 30, 2018: Zhongguo Yi Xue Ke Xue Yuan Xue Bao. Acta Academiae Medicinae Sinicae
Eva Braig, Jessica Böhm, Martin Dierolf, Christoph Jud, Benedikt Günther, Korbinian Mechlem, Sebastian Allner, Thorsten Sellerer, Klaus Achterhold, Bernhard Gleich, Peter Noël, Daniela Pfeiffer, Ernst Rummeny, Julia Herzen, Franz Pfeiffer
Dual-energy CT has opened up a new level of quantitative X-ray imaging for many diagnostic applications. The energy dependence of the X-ray attenuation is the key to quantitative material decomposition of the volume under investigation. This material decomposition allows the calculation of virtual native images in contrast enhanced angiography, virtual monoenergetic images for beam-hardening artifact reduction and quantitative material maps, among others. These visualizations have been proven beneficial for various diagnostic questions...
November 6, 2018: Scientific Reports
Simon Lennartz, Kai Roman Laukamp, Victor Neuhaus, Nils Große Hokamp, Markus Le Blanc, Volker Maus, Christoph Kabbasch, Anastasios Mpotsaris, David Maintz, Jan Borggrefe
PURPOSE: Retrospective comparison of diagnostic quality of virtual monoenergetic images (VMI) and conventional images (CI) reconstructed from dual-layer detector CT (DLCT) regarding intraparenchymal hemorrhage (IPH) and hypodense parenchymal lesions (HPL) of the brain. METHODS: 58 patients underwent unenhanced DLCT of the head. CI and VMI ranging from 40 to 120 keV were reconstructed. Objective image quality was assessed using ROI-based measurements within IPH, HPL, grey matter, white matter and cerebrospinal fluid, from which contrast to noise ratio (CNR) was calculated...
November 2018: European Journal of Radiology
Steven Van Hedent, Nils Große Hokamp, Rivka Kessner, Robert Gilkeson, Pablo R Ros, Amit Gupta
OBJECTIVE: The aim of this study was to investigate the quantitative and qualitative effects of virtual monoenergetic images (VMI) by spectral detector computed tomography (SDCT) on calcium blooming in coronary computed tomography angiography. METHODS: Coronary computed tomography angiography using SDCT was performed on 42 patients with coronary artery calcifications. Stenosis grading by diameter and area of calcified plaques and free lumen using VMI from 70 to 140 keV was performed and compared with measurements by conventional images...
November 2018: Journal of Computer Assisted Tomography
Nils Große Hokamp, Verena C Obmann, Rivka Kessner, Robert C Gilkeson, Amit Gupta, Thorsten Persigehl, Stefan Haneder, Nikhil Ramaiya
OBJECTIVE: The aim of the study was to establish the reference window settings for display of virtual monoenergetic images (VMIs) from spectral detector computed tomography when assessing hypodense liver lesions. METHODS: In patients with cysts (n = 24) or metastases (n = 26), objective (HU, signal-to-noise ratio [SNR]) and subjective (overall image quality, lesion conspicuity and noise) were assessed. Furthermore, 2 readers determined optimal window center/width (C/W) for conventional images (CIs) and VMIs of 40 to 120 keV...
November 2018: Journal of Computer Assisted Tomography
Anish A Patel, Patrick D Sutphin, Yin Xi, Suhny Abbara, Sanjeeva P Kalva
OBJECTIVE: To assess the feasibility of creating virtual monoenergetic arterial images from venous phase CTA obtained on a detector-based spectral CT scanner and quantitatively compare the signal-to-noise (SNR) and contrast-to-noise (CNR) ratios of the major arteries to those on polyenergetic true arterial phase images. METHODS: In this retrospective study, 23 patients (15 men and 8 women, median age 68 years) who underwent triple-phase CTA on a spectral CT scanner for aortic endograft surveillance were included...
October 24, 2018: Cardiovascular and Interventional Radiology
Michael C Burke, Ankur Garg, Jonathan M Youngner, Swati D Deshmukh, Imran M Omar
OBJECTIVE: Our purpose was to determine whether dual-energy CT (DECT), specifically the bone marrow setting of the virtual noncalcium (VNCa) algorithm, could be used to identify and accurately biopsy suspected bone malignancies that were visible on magnetic resonance imaging (MRI), nuclear bone scintigraphy, or positron-emission tomography/computed tomography (PET/CT), but occult on monoenergetic computed tomography (CT) by virtue of being either isodense or nearly isodense to surrounding normal bone...
October 20, 2018: Skeletal Radiology
Matthias Stefan May, Marco Wiesmueller, Rafael Heiss, Michael Brand, Joscha Bruegel, Michael Uder, Wolfgang Wuest
OBJECTIVES: The aim of this study was to compare image quality of single-source dual-energy CT (SS-DECT) with third-generation dual-source dual-energy CT (DS-DECT) in head and neck cancer. MATERIALS AND METHODS: One hundred two patients with histologically proven head and neck cancer were prospectively randomized to undergo radiation dose-matched SS-DECT (n = 51, 120 kV, split-filter technique, 384 ref. mAs) or DS-DECT (n = 51, 80/Sn150 kV, tube A 100/tube B 67 ref...
October 18, 2018: European Radiology
Philippe Jagoda, Daniel Schmitz, Stefan Wagenpfeil, Arno Bücker, Peter Minko
OBJECTIVE: The objective of this study was to compare the capability of two algorithms for metal artifact reduction and virtual monoenergetic imaging (VME), a metal artifact reduction application for dual-source CT. MATERIALS AND METHODS: A bovine vertebra phantom with 16 artificial osteolyses and two 20 × 4.5 mm stainless steel screws was scanned on two single-source CT scanner and one dual-source CT scanner at a dose identical to the single-source acquisitions...
December 2018: AJR. American Journal of Roentgenology
Daisuke Sueta, Daisuke Utsunomiya, Yasuhiro Izumiya, Takeshi Nakaura, Seitaro Oda, Koichi Kaikita, Yasuyuki Yamashita, Kenichi Tsujita
Because the prognosis of pulmonary thromboembolism (PTE) will be often poor, early diagnosis and assessing severity at the first visit is important. A 76-year-old man with suspected venous thromboembolism and a contrast deficit in the pulmonary artery (PA) was revealed by contrast-enhanced computed tomography (CT) imaging by dual-layer spectral-detector CT (IQon Spectral CT® , Philips Healthcare, Best, The Netherlands). The lung perfusion image showed decreased perfusion in the culprit lesion. The dual-energy analysis of the virtual monoenergetic imaging showed clear visualization of deep vein thrombosis (DVT)...
September 2018: Journal of Cardiology Cases
Hye Jin Yoo, Sung Hwan Hong, Bo Mi Chung, Sun Jeong Moon, Ja-Young Choi, Hee Dong Chae, Min-Yung Chang
OBJECTIVE: The purpose of this study was to evaluate the image quality of virtual monoenergetic images obtained from dual-layer-detector spectral CT of patients with metallic orthopedic implants of the distal radius. MATERIALS AND METHODS: A retrospective analysis was performed between April 2016 and January 2017. Forty-three consecutively registered patients (33 women, 10 men; mean age, 50.7 ± 15.4 years) with metallic implants for distal radius fractures underwent dual-layer-detector spectral CT...
November 2018: AJR. American Journal of Roentgenology
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