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Cheng Jin, Jianjiang Feng, Lei Wang, Heng Yu, Jiang Liu, Jiwen Lu, Jie Zhou
In this paper, we present an approach for left atrial appendage (LAA) multi-phase fast segmentation and quantitative assisted diagnosis of atrial fibrillation (AF) based on 4D-CT data. We take full advantage of the temporal dimension information to segment the living, flailed LAA based on a parametric max-flow method and graph-cut approach to build 3-D model of each phase. To assist the diagnosis of AF, we calculate the volumes of 3-D models, and then generate a "volume-phase" curve to calculate the important dynamic metrics: ejection fraction, filling flux, and emptying flux of the LAA's blood by volume...
March 9, 2018: Computers in Biology and Medicine
Satoshi Shibata, Shigeyuki Takamatsu, Kazutaka Yamamoto, Miu Mizuhata, Sayuri Bou, Yoshitaka Sato, Mariko Kawamura, Satoko Asahi, Yuji Tameshige, Yoshikazu Maeda, Makoto Sasaki, Tomoyasu Kumano, Satoshi Kobayashi, Hiroyasu Tamamura, Toshifumi Gabata
We evaluated the effectiveness and toxicity of proton beam therapy (PBT) for hepatocellular carcinomas (HCC) >5 cm without fiducial markers using four-dimensional CT (4D-CT) planning. The subjects were 29 patients treated at our hospital between March 2011 and March 2015. The median total dose was 76 Cobalt Gray Equivalents (CGE) in 20 fractions (range; 66-80.5 CGE in 10-32 fractions). Therapy was delivered with end-expiratory phase gating. An internal target volume (ITV) margin was added through the analysis of respiratory movement with 4D-CT...
March 14, 2018: Cancers
Nima Rostampour, Keyvan Jabbari, Mahdad Esmaeili, Mohammad Mohammadi, Shahabedin Nabavi
Background: Accurate delivery of the prescribed dose to moving lung tumors is a key challenge in radiation therapy. Tumor tracking involves real-time specifying the target and correcting the geometry to compensate for the respiratory motion, that's why tracking the tumor requires caution. This study aims to develop a markerless lung tumor tracking method with a high accuracy. Methods: In this study, four-dimensional computed tomography (4D-CT) images of 10 patients were used, and all the slices which contained the tumor were contoured for all patients...
January 2018: Journal of Medical Signals and Sensors
Federico Canè, Benedict Verhegghe, Matthieu De Beule, Philippe B Bertrand, Rob J Van der Geest, Patrick Segers, Gianluca De Santis
With cardiovascular disease (CVD) remaining the primary cause of death worldwide, early detection of CVDs becomes essential. The intracardiac flow is an important component of ventricular function, motion kinetics, wash-out of ventricular chambers, and ventricular energetics. Coupling between Computational Fluid Dynamics (CFD) simulations and medical images can play a fundamental role in terms of patient-specific diagnostic tools. From a technical perspective, CFD simulations with moving boundaries could easily lead to negative volumes errors and the sudden failure of the simulation...
2018: BioMed Research International
Yasushi Shibasaki, Takanori Sakaguchi, Ryo Kitajima, Satoru Furuhashi, Ryota Kiuchi, Makoto Takeda, Takanori Hiraide, Yoshifumi Morita, Naoki Unno, Hiroya Takeuchi
Pancreaticoduodenal artery (PDA) aneurysm associated with celiac axis compression by the median arcuate ligament (MAL) is a rare disorder, but may be lethal if ruptured. Therefore, prophylactic surgical treatments need to be considered when MAL compresses the celiac axis. We herein report the usefulness of an arterial flow analysis for objectively evaluating this pathophysiology under four-dimensional flow-sensitive magnetic resonance imaging (4D-flow MRI). Celiac artery stenosis was incidentally found under contrast-enhanced CT in a 50-year-old woman with symptomatic solitary pancreatic insulinoma...
March 5, 2018: Clinical Journal of Gastroenterology
Yusuke Kimura, Takeshi Mikami, Kei Miyata, Hime Suzuki, Toru Hirano, Katsuya Komatsu, Nobuhiro Mikuni
Recent advances in computed tomography angiography (CTA) enable repeated imaging follow up for post-clipping surgery. The purpose of this study was to clarify the critical volume and configuration of the aneurysmal clip in the postoperative evaluation using volume rendering (VR) imaging, and present four-dimensional (4D)-CTA for these larger metal artifacts. A total of 44 patients with cerebral aneurysm, treated using clipping surgery, were included in this study. The metal artifact volume was assessed using CTA and the association between the type of clips and its metal artifact volume was analyzed...
March 3, 2018: Neurosurgical Review
Moska Hamidi, Michael Sullivan, George Hunter, Leena Hamberg, Nancy L Cho, Atul A Gawande, Gerard M Doherty, Francis D Moore, Matthew A Nehs
BACKGROUND: Recurrent primary hyperparathyroidism (PHPT) presents a diagnostic challenge in localizing a hyperfunctioning gland. Although several imaging modalities are available for preoperative localization, 4D-CT is increasingly utilized for its ability to locate both smaller and previously unlocalized lesions. Currently, there is a paucity of data evaluating the utility of 4D-CT in the reoperative setting compared with ultrasound (US) and sestamibi. We aimed to determine the sensitivity of 4D-CT in localizing parathyroid adenomas in recurrent or persistent PHPT...
February 26, 2018: Annals of Surgical Oncology
Yoshinobu Shimohigashi, Fujio Araki, Masato Maruyama, Keisuke Yonemura, Yuji Nakaguchi, Yudai Kai, Ryo Toya
In this study, qualities of 4D cone-beam CT (CBCT) images obtained using various gantry rotation speeds (GRSs) for liver stereotactic body radiation therapy (SBRT) with fiducial markers were quantitatively evaluated. Abdominal phantom containing a fiducial marker was moved along a sinusoidal waveform, and 4D-CBCT images were acquired with GRSs of 50-200° min-1 . We obtained the 4D-CBCT projection data from six patients who underwent liver SBRT and generated 4D-CBCT images at GRSs of 67-200° min-1 , by varying the number of projection data points...
January 2018: Physica Medica: PM
Montserrat Carles, Thomas Bach, Irene Torres-Espallardo, Dimos Baltas, Ursula Nestle, Luis Martí-Bonmatí
In lung cancer, quantification by Positron-Emission-Tomography/Computed-Tomography (PET/CT) imaging presents challenges due to respiratory movement. Our primary aim was to study the impact of the compensation of motion implied by retrospectively gated (4D)-PET/CT on the variability of PET quantitative parameters. Its significance was evaluated by comparison with respect to the variability due to (i) the voxel size comprised by image reconstruction and (ii) the voxel size in image post-resampling. The method employed for features extraction was chosen based on the analysis of: (i) the effect of the standardized-uptake-value (SUV) discretization on the complementarity between texture features (TF) and the conventional indexes; (ii) the impact of the segmentation method on image features variability and (iii) the variability of image features across the time frames of 4D-PET...
February 22, 2018: Physics in Medicine and Biology
Filipa Guerreiro, Enrica Seravalli, Geert O Janssens, Cees P van de Ven, Marry M van den Heuvel-Eibrink, Bas W Raaymakers
BACKGROUND AND PURPOSE: To assess intra- and inter-fraction motion uncertainties, due to displacements of the tumor bed (TB) and organs at risk (OAR), as well as intra- and inter-fraction patient set-up uncertainties, due to positioning variations, during image-guided radiation therapy (IGRT) in children with Wilms' tumor. MATERIAL AND METHODS: Four-dimensional computed tomography (4D-CT) and daily pre- and post-treatment cone-beam CT (CBCT)-scans of 15 patients (average 4, range 1-8 years) undergoing flank irradiation after nephrectomy were analyzed...
February 19, 2018: Acta Oncologica
Dario Di Perri, Andréa Colot, Antoine Delor, Randa Ghoul, Guillaume Janssens, Valérie Lacroix, Pascal Matte, Annie Robert, Kevin Souris, Xavier Geets
PURPOSE: By increasing lung volume and decreasing respiration-induced tumour motion amplitude, administration of continuous positive airway pressure (CPAP) during stereotactic ablative radiotherapy (SABR) could allow for better sparing of the lungs and heart. In this study, we evaluated the effect of CPAP on lung volume, tumour motion amplitude and baseline shift, as well as the dosimetric impact of the strategy. METHODS: Twenty patients with lung tumours referred for SABR underwent 4D-computed tomography (CT) scans with and without CPAP (CPAP/noCPAP) at two timepoints (T0/T1)...
February 15, 2018: Strahlentherapie und Onkologie: Organ der Deutschen Röntgengesellschaft ... [et Al]
Shingo Ohira, Kentaro Wada, Takero Hirata, Naoyuki Kanayama, Toshiki Ikawa, Tsukasa Karino, Yuya Nitta, Masaru Isono, Yoshihiro Ueda, Masayoshi Miyazaki, Masahiko Koizumi, Teruki Teshima
BACKGROUND AND PURPOSE: The accurate delineation of pancreatic tumor with respiratory motion is challenging. This study demonstrates the application of contrast-enhanced four-dimensional dual-energy computed tomography (CE-4D-DECT) for tumor delineation and assesses the objective and subjective image quality. MATERIAL AND METHODS: Twelve patients underwent CE-4D-DECT, and quantitative spectral analysis was performed on the resulting virtual monochromatic images (VMI) to determine the optimal VMI (O-VMI) with the highest contrast-to-noise ratio (CNR)...
February 5, 2018: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
Vikas Gupta, Jonas Lantz, Lilian Henriksson, Jan Engvall, Matts Karlsson, Anders Persson, Tino Ebbers
BACKGROUND: Assessment of myocardial deformation from time-resolved cardiac computed tomography (4D CT) would augment the already available functional information from such an examination without incurring any additional costs. A deformable image registration (DIR) based approach is proposed to allow fast and automatic myocardial tracking in clinical 4D CT images. METHODS: Left ventricular myocardial tissue displacement through a cardiac cycle was tracked using a B-spline transformation based DIR...
February 2, 2018: Journal of Cardiovascular Computed Tomography
R Frood, R Prestwich, C Tsoumpas, P Murray, K Franks, A Scarsbrook
AIMS: A systematic review of the literature evaluating the clinical use of respiratory-gated (four-dimensional; 4D) fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) compared with non-gated (three-dimensional; 3D) PET/CT for radiotherapy planning in lung cancer. MATERIALS AND METHODS: A search of MEDLINE, Cochrane, Web of Science, SCOPUS and databases was undertaken for articles comparing 3D and 4D PET/CT tumour volume or 4D PET/CT for radiotherapy planning...
January 31, 2018: Clinical Oncology: a Journal of the Royal College of Radiologists
Slade J Klawikowski, An Tai, Ozgur Ates, Ergun Ahunbay, X Allen Li
PURPOSE: Four-dimensional volumetric modulated arc therapy (4D VMAT) and four-dimensional intensity modulated radiotherapy (4D IMRT) are developing radiation therapy treatment strategies designed to maximize dose conformality, minimize normal tissue dose, and deliver the treatment as efficiently as possible. The patient's entire breathing cycle is captured through 4D imaging modalities and then separated into individual breathing phases for planning purposes. Optimizing multi-phase VMAT and IMRT plans is computationally demanding and currently impractical for clinical application...
February 2, 2018: Medical Physics
Julia Carmen Schäfer, Holger Haubenreisser, Mathias Meyer, Joachim Grüttner, Thomas Walter, Martin Borggrefe, Joseph U Schoepf, John W Nance, Stefan O Schönberg, Thomas Henzler
INTRODUCTION:  To prospectively evaluate the feasibility of single contrast bolus high-pitch CT pulmonary angiography (CTPA) subsequently followed by low-dose retrospectively ECG-gated cardiac CT (4D-cCT) in patients with suspected pulmonary embolism (PE) to accurately evaluate right ventricular (RV) function. MATERIALS AND METHODS:  62 patients (33 female, age 65.1 ± 17.5 years) underwent high-pitch CTPA examination with 80cc of iodinated contrast material...
February 1, 2018: RöFo: Fortschritte Auf Dem Gebiete der Röntgenstrahlen und der Nuklearmedizin
Mitsuhiro Nakamura, Yoshitomo Ishihara, Yukinori Matsuo, Yusuke Iizuka, Nami Ueki, Hiraku Iramina, Hideaki Hirashima, Takashi Mizowaki
Knowledge of the imaging doses delivered to patients and accurate dosimetry of the radiation to organs from various imaging procedures is becoming increasingly important for clinicians. The purposes of this study were to calculate imaging doses delivered to the organs of lung cancer patients during real-time tumor tracking (RTTT) with three-dimensional (3D), and four-dimensional (4D) cone-beam computed tomography (CBCT), using Monte Carlo techniques to simulate kV X-ray dose distributions delivered using the Vero4DRT...
January 27, 2018: Journal of Radiation Research
Hyun Woo Goo
Objective: To evaluate the technical feasibility of four-dimensional (4D) CT for the functional evaluation of the pediatric diaphragm. Materials and Methods: In 22 consecutive children (median age 3.5 months, age range 3 days-3 years), 4D CT was performed to assess diaphragm motion. Diaphragm abnormalities were qualitatively evaluated and diaphragm motion was quantitatively measured on 4D CT. Lung density changes between peak inspiration and expiration were measured in the basal lung parenchyma...
January 2018: Korean Journal of Radiology: Official Journal of the Korean Radiological Society
Dylan O'Connell, Dan Ruan, David H Thomas, Tai H Dou, John H Lewis, Anand P Santhanam, Percy P Lee, Daniel A Low
Breathing motion modeling requires observation of tissues at sufficiently distinct respiratory states for proper 4D characterization. This work proposes a method to improve sampling of the breathing cycle with limited imaging dose. We designed and tested a prospective free-breathing acquisition protocol with a simulation using datasets from 5 patients imaged with a model-based 4DCT technique. Each dataset contained 25 free-breathing fast helical CT scans with simultaneous breathing surrogate measurements...
January 19, 2018: Physics in Medicine and Biology
Yolanda D Tseng, Landon Wootton, Matthew Nyflot, Smith Apisarnthanarax, Ramesh Rengan, Charles Bloch, George Sandison, Sara St James
Four dimensional computed tomography (4DCT) scans are routinely used in radiation therapy to determine the internal treatment volume for targets that are moving (e.g. lung tumors). The use of these studies has allowed clinicians to create target volumes based upon the motion of the tumor during the imaging study. The purpose of this work is to determine if a target volume based on a single 4DCT scan at simulation is sufficient to capture thoracic motion. Phantom studies were performed to determine expected differences between volumes contoured on 4DCT scans and those on the evaluation CT scans (slow scans)...
January 18, 2018: Physics in Medicine and Biology
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