Determination of a cone-beam CT low-dose protocol for root fracture diagnosis in non-endodontically treated anterior maxillary teeth

2021 ◽  
pp. 20210138
Author(s):  
Fedil Andraws Yalda ◽  
Chrysoula Theodorakou ◽  
Rosalyn J Clarkson ◽  
Jonathan Davies ◽  
Lee Feinberg ◽  
...  
Keyword(s):  
Image Quality ◽  
Diagnostic Accuracy ◽  
Dose Reduction ◽  
Low Dose ◽  
Ex Vivo ◽  
Characteristic Curve ◽  
Ex Vivo Model ◽  
Contrast Resolution ◽  
Anterior Teeth ◽  
Root Fractures

Objectives: The aim of this study was to determine a “low-dose protocol” which provides acceptable diagnostic accuracy for detection of root fractures in unrestored anterior maxillary teeth, using an ex vivo model. Methods: 48 maxillary anterior teeth, half with horizontal or oblique root fractures, were imaged using CBCT in an anthropomorphic model. Nine X-ray exposure combinations were used, including the manufacturer’s standard (“reference”) exposure and high-resolution settings (“HiRes”), by varying kV, exposure time, and rotation angle. Measurements of Dose Area Product (DAP) were recorded. Five dental radiologists assessed the scans for root fractures and judged image quality. Parameters of diagnostic accuracy were calculated, including area under the Receiver Operating Characteristic curve (Az). Objective measures of image quality were made at the same exposure combinations using an image quality phantom. Results: Although there was a significant linear relationship between DAP and mean Az, only the lowest DAP exposure combination had a mean Az significantly different to the reference exposure. There was no significant effect on other diagnostic accuracy parameters when using HiRes compared with the reference exposure. There was a significant positive relationship between DAP and contrast resolution. HiRes did not significantly improve contrast resolution and made a small improvement to spatial resolution. Conclusions: Scope existed for radiation dose reduction compared with the manufacturer’s guidance. There was no improvement in diagnostic accuracy using HiRes settings. A cautious recommendation for this CBCT machine is that it is possible to achieve a dose reduction of about 20% compared with the reference exposure parameters.

Ultra-Low-Dose CT of the Thorax Using Iterative Reconstruction: Evaluation of Image Quality and Radiation Dose Reduction

2015 ◽  
Vol 204 (6) ◽  
pp. 1197-1202 ◽  
Author(s):  
Yookyung Kim ◽  
Yoon Kyung Kim ◽  
Bo Eun Lee ◽  
Seok Jeong Lee ◽  
Yon Ju Ryu ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Dose Reduction ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Radiation Dose Reduction ◽  
Low Dose Ct

scholarly journals Influence of a novel deep-learning based reconstruction software on the objective and subjective image quality in low-dose abdominal computed tomography

2021 ◽  
Vol 94 (1117) ◽  
pp. 20200677
Author(s):  
Andrea Steuwe ◽  
Marie Weber ◽  
Oliver Thomas Bethge ◽  
Christin Rademacher ◽  
Matthias Boschheidgen ◽  
...  
Keyword(s):  
Deep Learning ◽  
Image Quality ◽  
Dose Reduction ◽  
Low Dose ◽  
Ct Images ◽  
Image Noise ◽  
The Novel ◽  
Subjective Image Quality ◽  
Image Information ◽  
Noise Ratio

Objectives: Modern reconstruction and post-processing software aims at reducing image noise in CT images, potentially allowing for a reduction of the employed radiation exposure. This study aimed at assessing the influence of a novel deep-learning based software on the subjective and objective image quality compared to two traditional methods [filtered back-projection (FBP), iterative reconstruction (IR)]. Methods: In this institutional review board-approved retrospective study, abdominal low-dose CT images of 27 patients (mean age 38 ± 12 years, volumetric CT dose index 2.9 ± 1.8 mGy) were reconstructed with IR, FBP and, furthermore, post-processed using a novel software. For the three reconstructions, qualitative and quantitative image quality was evaluated by means of CT numbers, noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in six different ROIs. Additionally, the reconstructions were compared using SNR, peak SNR, root mean square error and mean absolute error to assess structural differences. Results: On average, CT numbers varied within 1 Hounsfield unit (HU) for the three assessed methods in the assessed ROIs. In soft tissue, image noise was up to 42% lower compared to FBP and up to 27% lower to IR when applying the novel software. Consequently, SNR and CNR were highest with the novel software. For both IR and the novel software, subjective image quality was equal but higher than the image quality of FBP-images. Conclusion: The assessed software reduces image noise while maintaining image information, even in comparison to IR, allowing for a potential dose reduction of approximately 20% in abdominal CT imaging. Advances in knowledge: The assessed software reduces image noise by up to 27% compared to IR and 48% compared to FBP while maintaining the image information. The reduced image noise allows for a potential dose reduction of approximately 20% in abdominal imaging.

Effect of a novel denoising technique on image quality and diagnostic accuracy in low-dose CT in patients with suspected appendicitis

2019 ◽  
Vol 116 ◽  
pp. 198-204 ◽  
Author(s):  
Manuel Kolb ◽  
Corinna Storz ◽  
Jong Hyo Kim ◽  
Jakob Weiss ◽  
Saif Afat ◽  
...  
Keyword(s):  
Image Quality ◽  
Diagnostic Accuracy ◽  
Low Dose ◽  
Suspected Appendicitis ◽  
Low Dose Ct

scholarly journals Feasibility of low-dose digital pulsed video-fluoroscopic swallow exams (VFSE): effects on radiation dose and image quality

2017 ◽  
Vol 58 (9) ◽  
pp. 1037-1044 ◽  
Author(s):  
Jakob Weiss ◽  
Mike Notohamiprodjo ◽  
Klement Neumaier ◽  
Minglun Li ◽  
Wilhelm Flatz ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Dose Reduction ◽  
Low Dose ◽  
Research Evaluation ◽  
Diagnostic Image Quality ◽  
Organ Doses ◽  
Dose Area Product ◽  
Thermoluminescent Dosimeters ◽  
Area Product

Background Fluoroscopy is a frequently used examination in clinical routine without appropriate research evaluation latest hardware and software equipment. Purpose To evaluate the feasibility of low-dose pulsed video-fluoroscopic swallowing exams (pVFSE) to reduce dose exposure in patients with swallowing disorders compared to high-resolution radiograph examinations (hrVFSE) serving as standard of reference. Material and Methods A phantom study (Alderson-Rando Phantom, 60 thermoluminescent dosimeters [TLD]) was performed for dose measurements. Acquisition parameters were as follows: (i) pVFSE: 76.7 kV, 57 mA, 0.9 Cu mm, pulse rate/s 30; (ii) hrVFSE: 68.0 kV, 362 mA, 0.2 Cu mm, pictures 30/s. The dose area product (DAP) indicated by the detector system and the radiation dose derived from the TLD measurements were analyzed. In a patient study, image quality was assessed qualitatively (5-point Likert scale, 5 = hrVFSE; two independent readers) and quantitatively (SNR) in 35 patients who subsequently underwent contrast-enhanced pVFSE and hrVFSE. Results Phantom measurements showed a dose reduction per picture of factor 25 for pVFSE versus hrVFSE images (0.0025 mGy versus 0.062 mGy). The DAP (µGym2) was 28.0 versus 810.5 (pVFSE versus hrVFSE) for an average examination time of 30 s. Direct and scattered organ doses were significantly lower for pVFSE as compared to hrVFSE ( P < 0.05). Image quality was rated 3.9 ± 0.5 for pVFSE versus the hrVFSE standard; depiction of the contrast agent 4.8 ± 0.3; noise 3.6 ± 0.5 ( P < 0.05); SNR calculations revealed a relative decreased of 43.9% for pVFSE as compared to hrVFSE. Conclusion Pulsed VFSE is feasible, providing diagnostic image quality at a significant dose reduction as compared to hrVFSE.

scholarly journals Optimization of Image Quality in Paediatric Computed Tomography

2021 ◽  
Author(s):  
Angjelina Protik
Keyword(s):  
Image Quality ◽  
Dose Reduction ◽  
Quantitative Data ◽  
Ct Image ◽  
Contrast Resolution ◽  
Diagnostic Quality ◽  
Advantages And Disadvantages ◽  
Phantom Studies ◽  
Ct Image Quality ◽  
The Impact

In this study the effects of ASIR™ and collimation on CT image quality (IQ) parameters were quantified. Catphan®600 phantom studies were performed on a GE HD750 64-slice scanner to investigate the impact of collimation 0.625mm vs. 5mm on the overall IQ. For noise and dose reduction ASIR™ was tested on 0.625mm collimation. The varying %ASIR™, scanned at 150mA and variable kVp and 50% ASIR™ compared to FBP on wide kVp/mA range was used. Image noise, CT# accuracy and uniformity, spatial and contrast resolution, MTF, CNR and Wiener spectrum analysis were performed on 0.625mmAX slices, 5mmAXMPR and 2mmCORMPR. Incremental advantages and disadvantages were seen with stepwise increase in %ASIR™. The 50% ASIR™ was found to be optimal blend for diagnostic quality and has potential for dose reduction in paediatric CT. This quantitative data could be used to design ASIR™-enhanced protocols with consideration of diagnostic task, balancing image quality and radiation dose.

scholarly journals CT Thorax lavdose - En sammenligning av et organdosemodulerings program X-CARE og vismut beskyttelse

2017 ◽  
Vol 3 (1) ◽  
pp. 10
Author(s):  
Mikael Oseberg ◽  
Vanessa Tran ◽  
Kim Hoang ◽  
Hilde Lauvhaug ◽  
Hung Thai Phero Nguyen
Keyword(s):  
Image Quality ◽  
Dose Reduction ◽  
Low Dose ◽  
Region Of Interest ◽  
Lung Parenchyma ◽  
Ct Scans ◽  
Parietal Pleura ◽  
Ct Examination ◽  
Thoracic Ct ◽  
Bismuth Shielding

InnledningComputertomografi (CT) er en hyppig utført undersøkelse i Norge. Både mammae og thyroidea er strålefølsomme organer som eksponeres ved en CT thorax undersøkelse. For å få ned inngangsdosen (ESD) til slike strålefølsomme organer kan man enten benytte seg av en organspesifikk adaptiv dose reduksjons protokoll (X-CARE) eller  isteden legge vismut beskyttelse over de strålefølsomme organene ved CT-undersøkelsen. I denne studien sammenligner vi huddosen (ESD) over mamma, samt bildekvalitet, ved bruk av disse to metodene ved en CT thorax lavdose undersøkelse?Material og metode30 spiral skanninger, hvorav ti standard lavdose, ti med vismut beskyttelse og ti med X-CARE, ble utført på et Alderson fantom, kombinert med Care Dose 4D, på en Siemens SOMATOM Definition Edge 128 CT maskin. ESD ble målt, CTDIvol og Dose-lengde-produkt (DLP) ble hentet ut fra doserapporten. Den objektive bildekvaliteten ble analysert, og vurdert ved hjelp av tre Region Of Interest (ROI), plassert hhv i luft, i lungeparenkymet og i pleura parietale. Signal til støyforhold (SNR) og kontrast til støyforhold (CNR) ble regnet ut ifra ROI verdiene.ResultaterESD til mamma viste dosereduksjon sammenlignet med en standard CT thorax lavdose; hhv 16,5 % dosereduksjon ved bruk av vismut beskyttelse, og 0,44 % ved X-CARE. Det var ingen forskjell i CTDIvol og DLP ved standard lavdose skanningen eller skanningen med vismut beskyttelse. Skanningen med X-CARE ga en økning i CTDIvol og DLP på omtrent 12 %. SNR og CNR i lungeparenkymet og pleura parietale var høyest ved standard lavdose undersøkelsen. Bildestøyen økte 48 % ved vismut og 26,4 % ved X-CARE.KonklusjonESD ble markant redusert ved CT thorax lavdose undersøkelsen med vismut beskyttelse, men ga samtidig en markant økning i bildestøyen. X-CARE reduserte ESD minimalt sammenlignet med standard lavdose skanningen, men ga økt bildestøy. Den mest effektive måten å oppnå en optimal lavdose undersøkelse på, er ved å utføre en standard CT thorax lavdose protokoll.   AbstractIntroductionComputed tomography (CT) is a frequent examination conducted in Norway. Mammae and thyroid gland are both dose sensitive body organs, which are being exposed during a thoracic CT examination. Therefore, an optimization of protocols is necessary and X-CARE (organ-based tube current modulation) or bismuth protection may be applied during a CT examination. Will the two methods give a difference in the entrance surface dose (ESD) to mamma and the image quality of a low-dose thoracic CT examination?Materials and methodsThirty spiral CT scans of which ten was standard low-dose, ten with bismuth shielding and ten with X-CARE was performed on an Alderson phantom, combined with CARE Dose 4D and carried out on a Siemens SOMATOM Definition Edge 128. Measures as ESD, CTDIvol and Dose-length-product (DLP) were obtained from the dose report. The image quality was analysed objectively and assessed using three Region of Interest (ROI), placed in air, lung parenchyma and parietal pleura. Signal to noise ratio (SNR) and contrast to noise ratio (CNR) were calculated from the ROI results.ResultsESD to the mammary gland demonstrated a dose reduction compared to a standard thoracic CT low dose. Respectively; 16.5 % dose reduction with bismuth shielding and 0.44 % with X-CARE. There was no difference in CTDIvol and DLP between the standard low-dose scans and the scans with bismuth shielding. The CT scans with X-CARE gave an increase in CTDIvol and DLP by approximately 12 %. SNR and CNR in the lung parenchyma and parietal pleura were highest during the standard low-dose scans. Bismuth shielding increased the noise with 48 % and X-CARE with 26,4 %.ConclusionESD was significantly reduced during the CT thoracic low-dose examination using bismuth shielding, however notably the bismut increased the image noise. X-CARE reduced the ESD minimally compared to the CT low-dose scans, and it also increased the image noise. The most efficient way to achieve an optimal thoracic CT examination is to use a standard low-dose protoco 

Application of low-dose CT combined with model-based iterative reconstruction algorithm in oncologic patients during follow-up: dose reduction and image quality

2021 ◽  
pp. 20201223
Author(s):  
Davide Ippolito ◽  
Cesare Maino ◽  
Anna Pecorelli ◽  
Ilaria Salemi ◽  
Davide Gandola ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Dose Reduction ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Ct Images ◽  
Ct Attenuation ◽  
Oncologic Patients ◽  
Attenuation Values

Objectives: To compare image quality and radiation dose of CT images reconstructed with model-based iterative reconstruction (MBIR) and hybrid-iterative (HIR) algorithm in oncologic patients. Methods: 125 oncologic patients underwent both contrast-enhanced low- (100 kV), and standard (120 kV) dose CT, were enrolled. Image quality was assessed by using a 4-point Likert scale. CT attenuation values, expressed in Hounsfield unit (HU), were recorded within a regions of interest (ROI) of liver, spleen, paraspinal muscle, aortic lumen, and subcutaneous fat tissue. Image noise, expressed as standard deviation (SD), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were calculated. Radiation dose were analyzed. Paired Student’s t-test was used to compare all continuous variables. Results: The overall median score assessed as image quality for CT images with the MBIR algorithm was significantly higher in comparison with HIR [4 (range 3–4) vs 3 (3-4), p = 0.017]. CT attenuation values and SD were significantly higher and lower, respectively, in all anatomic districts in images reconstructed with MBIR in comparison with HIR ones (all p < 0.001). SNR and CNR values were higher in CT images reconstructed with MBIR, reaching a significant difference in all districts (all p < 0.001). Radiation dose were significantly lower in the MBIR group compared with the HIR group (p < 0.001). Conclusions: MBIR combined with low-kV setting allows an important dose reduction in whole-body CT imaging, reaching a better image quality both qualitatively and quantitatively. Advances in knowledge: MBIR with low-dose approach allows a reduction of dose exposure, maintaining high image quality, especially in patients which deserve a longlasting follow-up.

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