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https://www.readbyqxmd.com/read/28493110/bem-based-simulation-of-lung-respiratory-deformation-for-ct-guided-biopsy
#1
Dong Chen, Weisheng Chen, Lipeng Huang, Xuegang Feng, Terry Peters, Lixu Gu
PURPOSE: Accurate and real-time prediction of the lung and lung tumor deformation during respiration are important considerations when performing a peripheral biopsy procedure. However, most existing work focused on offline whole lung simulation using 4D image data, which is not applicable in real-time image-guided biopsy with limited image resources. In this paper, we propose a patient-specific biomechanical model based on the boundary element method (BEM) computed from CT images to estimate the respiration motion of local target lesion region, vessel tree and lung surface for the real-time biopsy guidance...
May 10, 2017: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/28477378/evaluating-the-accuracy-of-4d-ct-ventilation-imaging-first-comparison-with-technegas-spect-ventilation
#2
Fiona Hegi-Johnson, Paul Keall, Jeff Barber, Chuong Bui, John Kipritidis
INTRODUCTION: Computed tomography ventilation imaging (CTVI) is a highly accessible functional lung imaging modality that can unlock the potential for functional avoidance in lung cancer radiation therapy. Previous attempts to validate CTVI against clinical ventilation single-photon emission computed tomography (V-SPECT) have been hindered by radioaerosol clumping artifacts. This work builds on those studies by performing the first comparison of CTVI with (99m) Tc-carbon ('Technegas'), a clinical V-SPECT modality featuring smaller radioaerosol particles with less clumping...
May 5, 2017: Medical Physics
https://www.readbyqxmd.com/read/28469512/does-motion-assessment-with-4-dimensional-computed-tomographic-imaging-for-non-small-cell-lung-cancer-radiotherapy-improve-target-volume-coverage
#3
Naseer Ahmed, Sankar Venkataraman, Kate Johnson, Keith Sutherland, Shaun K Loewen
INTRODUCTION: Modern radiotherapy with 4-dimensional computed tomographic (4D-CT) image acquisition for non-small cell lung cancer (NSCLC) captures respiratory-mediated tumor motion to provide more accurate target delineation. This study compares conventional 3-dimensional (3D) conformal radiotherapy (3DCRT) plans generated with standard helical free-breathing CT (FBCT) with plans generated on 4D-CT contoured volumes to determine whether target volume coverage is affected. MATERIALS AND METHODS: Fifteen patients with stage I to IV NSCLC were enrolled in the study...
2017: Clinical Medicine Insights. Oncology
https://www.readbyqxmd.com/read/28467314/subpopulation-based-correspondence-modelling-for-improved-respiratory-motion-estimation-in-the-presence-of-inter-fraction-motion-variations
#4
Matthias Wilms, René Werner, Tokihiro Yamamoto, Heinz Handels, Jan Ehrhardt
Correspondence modelling between low-dimensional breathing signals and internal organ motion is a prerequisite for application of advanced techniques in radiotherapy of moving targets. Patient-specific correspondence models can, for example, be built prior to treatment based on a planning 4D CT and simultaneously acquired breathing signals. Reliability of pre-treatment-built models depends, however, on the degree of patient-specific inter-fraction motion variations. This study investigates whether motion estimation accuracy in the presence of inter-fraction motion variations can be improved using correspondence models that incorporate motion information from different patients...
May 3, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28464747/cone-beam-ct-based-set-up-strategies-with-and-without-rotational-correction-for-stereotactic-body-radiation-therapy-in-the-liver
#5
Jenny Bertholet, Esben Worm, Morten Høyer, Per Poulsen
BACKGROUND: Accurate patient positioning is crucial in stereotactic body radiation therapy (SBRT) due to a high dose regimen. Cone-beam computed tomography (CBCT) is often used for patient positioning based on radio-opaque markers. We compared six CBCT-based set-up strategies with or without rotational correction. MATERIAL AND METHODS: Twenty-nine patients with three implanted markers received 3-6 fraction liver SBRT. The markers were delineated on the mid-ventilation phase of a 4D-planning-CT...
June 2017: Acta Oncologica
https://www.readbyqxmd.com/read/28460004/4d-flow-cardiac-magnetic-resonance-derived-vorticity-is-sensitive-marker-of-left-ventricular-diastolic-dysfunction-in-patients-with-mild-to-moderate-chronic-obstructive-pulmonary-disease
#6
Michal Schäfer, Stephen Humphries, Kurt R Stenmark, Vitaly O Kheyfets, J Kern Buckner, Kendall S Hunter, Brett E Fenster
Aims: To investigate the possibility that vorticity assessed by four-dimensional flow cardiac magnetic resonance (4D-Flow CMR) in the left ventricle of patients with mild-to-moderate chronic obstructive pulmonary disease (COPD) is a potential marker of early LV diastolic dysfunction (LVDD) and more sensitive than standard echocardiography, and whether changes in vorticity are associated with quantitative computed tomography (CT) and clinical markers of COPD, and right ventricular (RV) echocardiographic markers indicative of ventricular interdependency...
April 27, 2017: European Heart Journal Cardiovascular Imaging
https://www.readbyqxmd.com/read/28458088/a-hybrid-patient-specific-biomechanical-model-based-image-registration-method-for-the-motion-estimation-of-lungs
#7
Lianghao Han, Hua Dong, Jamie R McClelland, Liangxiu Han, David J Hawkes, Dean C Barratt
This paper presents a new hybrid biomechanical model-based non-rigid image registration method for lung motion estimation. In the proposed method, a patient-specific biomechanical modelling process captures major physically realistic deformations with explicit physical modelling of sliding motion, whilst a subsequent non-rigid image registration process compensates for small residuals. The proposed algorithm was evaluated with 10 4D CT datasets of lung cancer patients. The target registration error (TRE), defined as the Euclidean distance of landmark pairs, was significantly lower with the proposed method (TRE = 1...
April 19, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/28440669/can-multiphase-dynamic-ct-angiography-provide-a-better-assessment-of-aortic-dissection-compared-with-the-standard-triphasic-protocol
#8
Chun-Yan Lu, Yi-Ke Diao, Ying-Qiang Guo, Xiao-Hui Zhang, Hong-Li Bai, Zhen-Lin Li
Background Acute aortic dissection (AD) is a life-threatening medical emergency. It has been debated whether the multiphase dynamic computed tomography angiography (CTA) protocol is superior to the standard triphasic protocol for revealing the characteristics of AD. Purpose To examine two multiphase dynamic protocols, Dynamic four-dimensional (4D) CTA using the shuttle mode and Flash 4D CTA using the high-pitch mode for the assessment of AD and to compare them with the standard triphasic protocol. Material and Methods A total of 54 consecutive patients were randomly and equally assigned to three groups and scanned with a second-generation DSCT scanner...
January 1, 2017: Acta Radiologica
https://www.readbyqxmd.com/read/28430590/treatment-of-esophageal-cancer-with-radiation-therapy-a-pan-chinese-survey-of-radiation-oncologists
#9
Yun Zhang, Jing Liu, Wencheng Zhang, Weiye Deng, Jinbo Yue
Lots of controversies were found about the treatment in relation to radiation therapy (RT) for esophageal squamous cell carcinoma (ESCC). We designed a questionnaire of these controversies to do a pan-Chinese survey of radiation oncologists (ROs). For operable ESCC, 53% ROs chose surgery plus postoperative chemoradiotherapy (CRT), while 40% chose preoperative CRT plus surgery. For target volume of postoperative RT, most ROs (92%) would delineate tumor bed plus involved lymph nodes region before surgery. For definitive RT, most ROs (81%) would give patients higher RT dose to 60-65Gy...
April 5, 2017: Oncotarget
https://www.readbyqxmd.com/read/28410685/evaluation-of-mesh-and-binary-based-contour-propagation-methods-in-4d-thoracic-radiotherapy-treatments-using-patient-4d-ct-images
#10
Yuanyuan Ma, Xinguo Liu, Zhongying Dai, Pengbo He, Yuanlin Yan, Guosheng Shen, Ping Yuan, Qiang Li
Based on four dimensional (4D) computed tomography (CT) images, mesh- and binary-based contour propagation algorithms for 4D thoracic radiotherapy treatments were evaluated. Gross tumor volumes (GTVs), lungs, hearts and spinal cords on the CT images at the end-exhale and end-inhale phases for six patients were delineated by the physician. All volumes of interest (VOIs) were automatically propagated from the end-exhale phase to the end-inhale phase using two propagation methods. The propagated VOIs were quantitatively compared with the VOIs contoured at the end-inhale phase by the physician using Dice Similarity Coefficient (DSC), Mean Slicewise Hausdorff Distance (MSHD), Center Of Mass (COM) displacement and volume difference...
April 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28408632/4d-dsa-for-dynamic-visualization-of-cerebral-vasculature-a-single-center-experience-in-26-cases
#11
S Lang, P Gölitz, T Struffert, J Rösch, K Rössler, M Kowarschik, C Strother, A Doerfler
BACKGROUND AND PURPOSE: 4D DSA allows acquisition of time-resolved 3D reconstructions of cerebral vessels by using C-arm conebeam CT systems. The aim of our study was to evaluate this new method by qualitative and quantitative means. MATERIALS AND METHODS: 2D and 4D DSA datasets were acquired in patients presenting with AVMs, dural arteriovenous fistulas, and cerebral aneurysms. 4D DSA was compared with 2D DSA in a consensus reading of qualitative and quantitative parameters of AVMs (eg, location, feeder, associated aneurysms, nidus size, drainage, Martin-Spetzler Score), dural arteriovenous fistulas (eg, fistulous point, main feeder, diameter of the main feeder, drainage), and cerebral aneurysms (location, neck configuration, aneurysmal size)...
April 13, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28390002/a-tool-for-validating-mri-guided-strategies-a-digital-breathing-ct-mri-phantom-of-the-abdominal-site
#12
Chiara Paganelli, Paul Summers, Chiara Gianoli, Massimo Bellomi, Guido Baroni, Marco Riboldi
Dynamic magnetic resonance imaging (MRI) is emerging as the elected image modality for organ motion quantification and management in image-guided radiotherapy. However, the lack of validation tools is an open issue for image guidance in the abdominal and thoracic organs affected by organ motion due to respiration. We therefore present an abdominal four-dimensional (4D) CT/MRI digital phantom, including the estimation of MR tissue parameters, simulation of dedicated abdominal MR sequences, modeling of radiofrequency coil response and noise, followed by k-space sampling and image reconstruction...
April 8, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28384187/target-localization-of-3d-versus-4d-cone-beam-computed-tomography-in-lipiodol-guided-stereotactic-radiotherapy-of-hepatocellular-carcinomas
#13
Mark Chan, Chi Leung Chiang, Venus Lee, Steven Cheung, Ronnie Leung, Matthew Wong, Frankle Lee, Oliver Blanck
BACKGROUND: Aim of this study was to comparatively evaluate the accuracy of respiration-correlated (4D) and uncorrelated (3D) cone beam computed tomography (CBCT) in localizing lipiodolized hepatocellular carcinomas during stereotactic body radiotherapy (SBRT). METHODS: 4D-CBCT scans of eighteen HCCs were acquired during free-breathing SBRT following trans-arterial chemo-embolization (TACE) with lipiodol. Approximately 1320 x-ray projections per 4D-CBCT were collected and phase-sorted into ten bins...
2017: PloS One
https://www.readbyqxmd.com/read/28372795/a-four-dimensional-computed-tomography-comparison-of-healthy-and-asthmatic-human-lungs
#14
Nariman Jahani, Sanghun Choi, Jiwoong Choi, Babak Haghighi, Eric A Hoffman, Alejandro P Comellas, Joel N Kline, Ching-Long Lin
The purpose of this study was to explore new insights in non-linearity, hysteresis and ventilation heterogeneity of asthmatic human lungs using four-dimensional computed tomography (4D-CT) image data acquired during tidal breathing. Volumetric image data were acquired for 5 non-severe and one severe asthmatic volunteers. Besides 4D-CT image data, function residual capacity and total lung capacity image data during breath-hold were acquired for comparison with dynamic scans. Quantitative results were compared with the previously reported analysis of five healthy human lungs...
May 3, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28371774/a-novel-method-of-cone-beam-ct-projection-binning-based-on-image-registration
#15
Seonyeong Park, Siyong Kim, Byongyong Yi, Geoffrey Hugo, H Michael Gach, Yuichi Motai
Accurate sorting of beam projections is important in four-dimensional Cone Beam Computed Tomography (4D CBCT) to improve the quality of the reconstructed 4D CBCT image by removing motion-induced artifacts. We propose Image Registration-based Projection Binning (IRPB), a novel marker-less binning method for 4D CBCT projections, which combines Intensity-based Feature Point Detection (IFPD) and Trajectory Tracking using Random sample consensus (TTR). IRPB extracts breathing motion and phases by analyzing tissue feature point trajectories...
March 31, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28369900/examination-of-a-deformable-motion-model-for-respiratory-movements-and-4d-dose-calculations-using-different-driving-surrogates
#16
Jens Wölfelschneider, Matteo Seregni, Aurora Fassi, Marc Ziegler, Guido Baroni, Rainer Fietkau, Marco Riboldi, Christoph Bert
PURPOSE: The aim of this study is to evaluate a surrogate-driven motion model based on four-dimensional computed tomography that is able to predict CT volumes corresponding to arbitrary respiratory phases. Further, the comparison of three different driving surrogates is examined and the feasibility of using the model for 4D dose re-calculation will be discussed. METHODS: The study is based on repeated 4DCTs of twenty patients treated for bronchial carcinoma and metastasis...
March 30, 2017: Medical Physics
https://www.readbyqxmd.com/read/28366753/the-position-and-role-of-4d-cta-in-the-diagnosis-and-treatment-of-spinal-arteriovenous-fistulas
#17
Satoshi Yamaguchi, Kohei Takemoto, Masaaki Takeda, Yosuke Kajihara, Takafumi Mitsuhara, Manish Kolakshyapati, Kazutoshi Mukada, Kaoru Kurisu
BACKGROUND: Localization of the arteriovenous fistula (AVF) is a crucial step in the diagnosis and treatment of spinal vascular malformations (VMs). Non-invasive angiographic techniques such as dynamic magnetic resonance angiography (MRA) and 3-dimensional computed tomography angiography (3D-CTA) have been used as standard modalities to localize AVF. With the increasing prevalence of high-spec CT scanner, 4D-CTA is being increasingly utilized in the evaluation of cerebrovascular disorders...
March 30, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28366054/advanced-imaging-in-acute-ischemic-stroke
#18
REVIEW
Craig Kilburg, J Scott McNally, Adam de Havenon, Philipp Taussky, M Yashar S Kalani, Min S Park
The evaluation and management of acute ischemic stroke has primarily relied on the use of conventional CT and MRI techniques as well as lumen imaging sequences such as CT angiography (CTA) and MR angiography (MRA). Several newer or less-established imaging modalities, including vessel wall MRI, transcranial Doppler ultrasonography, and 4D CTA and MRA, are being developed to complement conventional CT and MRI techniques. Vessel wall MRI provides high-resolution analysis of both extracranial and intracranial vasculature to help identify previously occult lesions or characteristics of lesions that may portend a worse natural history...
April 2017: Neurosurgical Focus
https://www.readbyqxmd.com/read/28363893/osseous-impingement-occurs-early-in-flexion-in-cam-type-femoroacetabular-impingement-a-4d-ct-model
#19
S Fernquest, C Arnold, A Palmer, J Broomfield, J Denton, A Taylor, S Glyn-Jones
AIMS: The aim of this study was to examine the real time in vivo kinematics of the hip in patients with cam-type femoroacetabular impingement (FAI). PATIENTS AND METHODS: A total of 50 patients (83 hips) underwent 4D dynamic CT scanning of the hip, producing real time osseous models of the pelvis and femur being moved through flexion, adduction, and internal rotation. The location and size of the cam deformity and its relationship to the angle of flexion of the hip and pelvic tilt, and the position of impingement were recorded...
April 2017: Bone & Joint Journal
https://www.readbyqxmd.com/read/28359341/monitoring-of-breathing-motion-in-image-guided-pbs-proton-therapy-comparative-analysis-of-optical-and-electromagnetic-technologies
#20
Giovanni Fattori, Sairos Safai, Pablo Fernández Carmona, Marta Peroni, Rosalind Perrin, Damien Charles Weber, Antony John Lomax
BACKGROUND: Motion monitoring is essential when treating non-static tumours with pencil beam scanned protons. 4D medical imaging typically relies on the detected body surface displacement, considered as a surrogate of the patient's anatomical changes, a concept similarly applied by most motion mitigation techniques. In this study, we investigate benefits and pitfalls of optical and electromagnetic tracking, key technologies for non-invasive surface motion monitoring, in the specific environment of image-guided, gantry-based proton therapy...
March 31, 2017: Radiation Oncology
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