scholarly journals A comprehensive assessment of physical image quality of five different scanners for head CT imaging as clinically used at a single hospital centre—A phantom study

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245374
Author(s):  
Patrizio Barca ◽  
Fabio Paolicchi ◽  
Giacomo Aringhieri ◽  
Federica Palmas ◽  
Daniela Marfisi ◽  
...  
Keyword(s):  
Image Quality ◽  
Coefficient Of Variation ◽  
Ct Imaging ◽  
Comprehensive Assessment ◽  
Phantom Study ◽  
Noise Power ◽  
Head Ct ◽  
Acquisition Protocol ◽  
Ct Scanners

Nowadays, given the technological advance in CT imaging and increasing heterogeneity in characteristics of CT scanners, a number of CT scanners with different manufacturers/technologies are often installed in a hospital centre and used by various departments. In this phantom study, a comprehensive assessment of image quality of 5 scanners (from 3 manufacturers and with different models) for head CT imaging, as clinically used at a single hospital centre, was hence carried out. Helical and/or sequential acquisitions of the Catphan-504 phantom were performed, using the scanning protocols (CTDIvol range: 54.7–57.5 mGy) employed by the staff of various Radiology/Neuroradiology departments of our institution for routine head examinations. CT image quality for each scanner/acquisition protocol was assessed through noise level, noise power spectrum (NPS), contrast-to-noise ratio (CNR), modulation transfer function (MTF), low contrast detectability (LCD) and non-uniformity index analyses. Noise values ranged from 3.5 HU to 5.7 HU across scanners/acquisition protocols. NPS curves differed in terms of peak position (range: 0.21–0.30 mm-1). A substantial variation of CNR values with scanner/acquisition protocol was observed for different contrast inserts. The coefficient of variation (standard deviation divided by mean value) of CNR values across scanners/acquisition protocols was 18.3%, 31.4%, 34.2%, 30.4% and 30% for teflon, delrin, LDPE, polystyrene and acrylic insert, respectively. An appreciable difference in MTF curves across scanners/acquisition protocols was revealed, with a coefficient of variation of f50%/f10% of MTF curves across scanners/acquisition protocols of 10.1%/7.4%. A relevant difference in LCD performance of different scanners/acquisition protocols was found. The range of contrast threshold for a typical object size of 3 mm was 3.7–5.8 HU. Moreover, appreciable differences in terms of NUI values (range: 4.1%-8.3%) were found. The analysis of several quality indices showed a non-negligible variability in head CT imaging capabilities across different scanners/acquisition protocols. This highlights the importance of a physical in-depth characterization of image quality for each CT scanner as clinically used, in order to optimize CT imaging procedures.

Assessment of image quality of 64-row Dual Source versus Single Source CT coronary angiography on heart rate: A phantom study

2009 ◽  
Vol 70 (1) ◽  
pp. 61-68 ◽  
Author(s):  
R. Dikkers ◽  
M.J.W. Greuter ◽  
W. Kristanto ◽  
P.M.A. van Ooijen ◽  
P.E. Sijens ◽  
...  
Keyword(s):  
Heart Rate ◽  
Image Quality ◽  
Coronary Angiography ◽  
Ct Coronary Angiography ◽  
Phantom Study ◽  
Single Source ◽  
Dual Source

scholarly journals Image quality of conventional images of dual‐layerSPECTRAL CT: A phantom study

2018 ◽  
Vol 45 (7) ◽  
pp. 3031-3042 ◽  
Author(s):  
Fasco Ommen ◽  
Edwin Bennink ◽  
Alain Vlassenbroek ◽  
Jan Willem Dankbaar ◽  
Arnold M.R. Schilham ◽  
...  
Keyword(s):  
Image Quality ◽  
Phantom Study

THE IMPACT OF HEAD POSITIONING ON THE IMAGE QUALITY OF MULTI-DETECTOR COMPUTED TOMOGRAPHY

2021 ◽  
pp. 2150050
Author(s):  
Yang-Ting Hsu ◽  
Jo-Chi Jao
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Control Group ◽  
Ct Scanner ◽  
Head Ct ◽  
Radiologic Technologists ◽  
Head Positioning ◽  
The Impact ◽  
Multi Detector Computed Tomography

Radiologic technologists face various types of patients during multi-detector computed tomography (CT) examinations. In emergency departments, it is common to have patients who cannot follow instructions for the examinations. The asymmetric axial view of the head CT might affect the correctness of the clinician’s diagnosis. This study aimed to assess the impact of head positioning on the image quality of head CT using two phantoms. All scans were performed on a 16-slice CT scanner. In the control group, the tilted angle of the phantoms was 0[Formula: see text], and no multiplanar reconstruction (MPR) was performed. In the experimental groups, the tilted angles of the phantoms were 5[Formula: see text], 10[Formula: see text] and 15[Formula: see text], respectively, and MPR was performed afterwards. The results showed that if the head was tilted during the head CT examinations, image asymmetry and artifacts appeared without MPR. After MPR, one phantom showed that there were significant differences and the other phantom showed no significant differences quantitatively in image symmetry and artifacts between experimental groups and the control group, while both phantoms showed no significant differences qualitatively in image symmetry and artifacts between experimental groups and the control group. Although MPR can correct the image asymmetry and artifacts caused by tilted head positioning to some extent, it consumes time. Therefore, technologists should position the head as exactly as possible when performing head CT examinations.

Acquisition time, radiation dose, subjective and objective image quality of dual-source CT scanners in acute pulmonary embolism: a comparative study

2020 ◽  
Vol 30 (5) ◽  
pp. 2712-2721 ◽  
Author(s):  
Waleed Abdellatif ◽  
Eric Esslinger ◽  
Kevin Kobes ◽  
Amanda Wong ◽  
Jennifer Powell ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
Image Quality ◽  
Radiation Dose ◽  
Comparative Study ◽  
Acute Pulmonary Embolism ◽  
Acquisition Time ◽  
Dual Source Ct ◽  
Dual Source ◽  
Ct Scanners

scholarly journals A phantom study comparing low-dose CT physical image quality from five different CT scanners

2021 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Yali Li ◽  
Yaojun Jiang ◽  
Huilong Liu ◽  
Xi Yu ◽  
Sihui Chen ◽  
...  
Keyword(s):  
Image Quality ◽  
Low Dose ◽  
Phantom Study ◽  
Low Dose Ct ◽  
Ct Scanners

scholarly journals Non-rigid image registration of 4D-MRI data for improved delineation of moving tumors 

2020 ◽  
Author(s):  
Stefan Weick ◽  
Kathrin Breuer ◽  
Anne Richter ◽  
Florian Exner ◽  
Serge-Peer Ströhle ◽  
...  
Keyword(s):  
Image Quality ◽  
Image Registration ◽  
Coefficient Of Variation ◽  
Regions Of Interest ◽  
Qualitative Assessment ◽  
Data Sets ◽  
Target Delineation ◽  
Tumor Delineation ◽  
4D Mri

Abstract Background: To increase the image quality of end-expiratory and end-inspiratory phases of retrospective respiratory self-gated 4D MRI data sets using non-rigid image registration for improved target delineation of moving tumors.Methods: End-expiratory and end-inspiratory phases of volunteer and patient 4D MRI data sets are used as targets for non-rigid image registration of all other phases using two different registration schemes: In the first, all phases are registered directly (dir-Reg) while next neighbors are successively registered until the target is reached in the second (nn-Reg). Resulting data sets are quantitatively compared using diaphragm and tumor sharpness and the coefficient of variation of regions of interest in the lung, liver, and heart. Qualitative assessment of the patient data regarding noise level, tumor delineation, and overall image quality was performed by blinded reading based on a 4 point Likert scale.Results: The median coefficient of variation was lower for both registration schemes compared to the target. Median dir-Reg coefficient of variation of all ROIs was 5.6 % lower for expiration and 7.0 % lower for inspiration compared with nn-Reg. Statistical significant differences between the two schemes were found in all comparisons. Median sharpness in inspiration is lower compared to expiration sharpness in all cases. Registered data sets were rated better compared to the targets in all categories. Over all categories, mean expiration scores were 2.92 ± 0.18 for the target, 3.19 ± 0.22 for nn-Reg and 3.56 ± 0.14 for dir-Reg and mean inspiration scores 2.25 ± 0.12 for the target, 2.72 ± 215 0.04 for nn-Reg and 3.78 ± 0.04 for dir-Reg.Conclusions: In this work, end-expiratory and inspiratory phases of a 4D MRI data sets are used as targets for non-rigid image registration of all other phases. It is qualitatively and quantitatively shown that image quality of the targets can be significantly enhanced leading to improved target delineation of moving tumors.

scholarly journals Image quality comparison between a phase-contrast synchrotron radiation breast CT and a clinical breast CT: a phantom based study

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Luca Brombal ◽  
Fulvia Arfelli ◽  
Pasquale Delogu ◽  
Sandro Donato ◽  
Giovanni Mettivier ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Image Quality ◽  
Spatial Resolution ◽  
Phase Retrieval ◽  
Medical Center ◽  
Equivalent Material ◽  
Noise Power ◽  
Breast Ct ◽  
Noise Ratio

AbstractIn this study we compared the image quality of a synchrotron radiation (SR) breast computed tomography (BCT) system with a clinical BCT in terms of contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), noise power spectrum (NPS), spatial resolution and detail visibility. A breast phantom consisting of several slabs of breast-adipose equivalent material with different embedded targets (i.e., masses, fibers and calcifications) was used. Phantom images were acquired using a dedicated BCT system installed at the Radboud University Medical Center (Nijmegen, The Netherlands) and the SR BCT system at the SYRMEP beamline of Elettra SR facility (Trieste, Italy) based on a photon-counting detector. Images with the SR setup were acquired mimicking the clinical BCT conditions (i.e., energy of 30 keV and radiation dose of 6.5 mGy). Images were reconstructed with an isotropic cubic voxel of 273 µm for the clinical BCT, while for the SR setup two phase-retrieval (PhR) kernels (referred to as “smooth” and “sharp”) were alternatively applied to each projection before tomographic reconstruction, with voxel size of 57 × 57 × 50 µm3. The CNR for the clinical BCT system can be up to 2-times higher than SR system, while the SNR can be 3-times lower than SR system, when the smooth PhR is used. The peak frequency of the NPS for the SR BCT is 2 to 4-times higher (0.9 mm−1 and 1.4 mm−1 with smooth and sharp PhR, respectively) than the clinical BCT (0.4 mm−1). The spatial resolution (MTF10%) was estimated to be 1.3 lp/mm for the clinical BCT, and 5.0 lp/mm and 6.7 lp/mm for the SR BCT with the smooth and sharp PhR, respectively. The smallest fiber visible in the SR BCT has a diameter of 0.15 mm, while for the clinical BCT is 0.41 mm. Calcification clusters with diameter of 0.13 mm are visible in the SR BCT, while the smallest diameter for the clinical BCT is 0.29 mm. As expected, the image quality of the SR BCT outperforms the clinical BCT system, providing images with higher spatial resolution and SNR, and with finer granularity. Nevertheless, this study assesses the image quality gap quantitatively, giving indications on the benefits associated with SR BCT and providing a benchmarking basis for its clinical implementation. In addition, SR-based studies can provide a gold-standard in terms of achievable image quality, constituting an upper-limit to the potential clinical development of a given technique.

scholarly journals Improving the image quality of DWI in breast cancer: comparison of multi-shot DWI using multiplexed sensitivity encoding to conventional single-shot echo-planar imaging DWI

2020 ◽  
pp. 20200427
Author(s):  
Gabrielle C Baxter ◽  
Andrew J Patterson ◽  
Ramona Woitek ◽  
Iris Allajbeu ◽  
Martin J Graves ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Image Quality ◽  
Coefficient Of Variation ◽  
Echo Planar Imaging ◽  
Single Shot ◽  
Planar Imaging ◽  
Benign Lesions ◽  
Sensitivity Encoding ◽  
Echo Planar

Objective: To compare diffusion-weighted images (DWI) acquired using single-shot echo-planar imaging (ss-EPI) and multiplexed sensitivity encoding (MUSE) in breast cancer. Methods 20 females with pathologically confirmed breast cancer (age 51 ± 12 years) were imaged with ss-EPI-DWI and MUSE-DWI. ADC, normalised ADC (nADC), blur and distortion metrics and qualitative image quality scores were compared. The Crété-Roffet and Mattes mutual information metrics were used to evaluate blurring and distortion, respectively. In a breast phantom, six permutations of MUSE-DWI with varying parallel acceleration factor and number of shots were compared. Differences in ADC and nADC were compared using the coefficient of variation in the phantom and a paired t-test in patients. Differences in blur, distortion and qualitative metrics were analysed using a Wilcoxon signed-rank test. Results: There was a low coefficient of variation (<2%) in ADC between ss-EPI-DWI and all MUSE-DWI permutations acquired using the phantom. 22 malignant and three benign lesions were identified in 20 patients. ADC values measured using MUSE were significantly lower compared to ss-EPI for malignant but not benign lesions (p < 0.001, p = 0.21). nADC values were not significantly different (p = 0.62, p = 0.28). Blurring and distortion improved with number of shots and acceleration factor, and significantly improved with MUSE in patients (p < 0.001, p = 0.002). Qualitatively, image quality improved using MUSE. Conclusion: MUSE improves the image quality of breast DWI compared to ss-EPI. Advances in knowledge: MUSE-DWI has superior image quality and reduced blurring and distortion compared to ss-EPI-DWI in breast cancer.

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