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.

scholarly journals Image quality of 16-slice computed tomography coronary angiography in patients with complete left bundle branch block

Medicina ◽  
2008 ◽  
Vol 45 (1) ◽  
pp. 14
Author(s):  
Antanas Jankauskas ◽  
Jurgita Zaveckienė ◽  
Gabija Pundziūtė ◽  
Rimvydas Šlapikas ◽  
Algidas Basevičius ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Heart Rate ◽  
Image Quality ◽  
Coronary Angiography ◽  
Left Bundle Branch Block ◽  
Multislice Computed Tomography ◽  
Quality Score ◽  
Control Group ◽  
Bundle Branch Block

Objective. Noninvasive diagnosis of coronary artery disease in patients with left bundle branch block is challenging. Multislice computed tomography can be useful in this population; however, quality of images depends on the patterns of myocardial contractions. We investigated the influence of left bundle branch block on image quality of multislice computed tomography coronary angiography. Materials and methods. Multislice computed tomography coronary angiography was performed in 30 patients with left bundle branch block and 30 patients without conduction disturbances. Image quality of each coronary segment was visually assessed and rated on a five-point scale (1=highest quality). Results. Average image quality score in the best cardiac cycle phase did not differ significantly between groups (1.71±0.59 in the left bundle branch block group vs. 1.60±0.57 in the control group, P=0.46). In the left bundle branch block group, a significantly lower image quality score was observed in end-systolic cardiac phase (2.67±0.6 vs. 2.22±0.65 in the control group, P=0.007), whereas no difference was demonstrated in mid-diastolic phase (1.73±0.6 vs. 1.69±0.66 in the control group, P=0.81). After image assessment in multiple cardiac phases, an increase in image quality score was higher in the left bundle branch block than in the control group (0.2±0.17 vs. 0.11±0.14, P=0.003). A negative correlation was observed between image quality score and both the heart rate and heart rate variability in both groups (P<0.001). Conclusion. A nonsignificantly lower overall image quality of multislice computed tomography coronary angiography was demonstrated in the left bundle branch block group. In the presence of left bundle branch block, image quality in the end-systolic phase was significantly lower. Image assessment in multiple phases increased overall image quality and is therefore advisable in patients with left bundle branch block. Increased heart rate and heart rate variability worsened image quality in both groups.

scholarly journals Utilization of sinogram affirmed iterative reconstruction on 128 multi slice computed tomography scan to reduce radiation dose and improve image quality on thorax multi slice computed tomography scan: chest phantom study

2019 ◽  
Vol 6 (10) ◽  
pp. 4533
Author(s):  
Halinda Fatmayanti ◽  
Kusworo Adi ◽  
Yeti Kartikasari
Keyword(s):  
Computed Tomography ◽  
Experimental Study ◽  
Image Quality ◽  
Radiation Dose ◽  
Dose Assessment ◽  
Computed Tomography Scan ◽  
Tube Voltage ◽  
The Impact ◽  
Tomography Scan

Background: Thorax MSCT examination is a diagnostic imaging that is capable of displaying both normal and pathological lung and respiratory organs. MSCT examination also has a better level of sensitivity and specificity compared to other modalities, but the radiation exposure given is very high, so the radiation dose given to patients is high. The reduction in radiation dose is very important because of the direct exposure to sensitive tissue. One method of reducing radiation dose is by reducing the tube voltage. However, the decrease in tube voltage causes a decrease in image quality as indicated by increased noise and decreased CNR. To maintain the quality of the image at low tube voltage setting, an IR reconstruction of SAFIRE was used. The purpose of this research is to know the impact of using SAFIRE on dose radiation and image quality of thorax MSCT.Methods: This study was an experimental study with a quasi-experimental study design. The object used was the N-1 Lungman chest phantom in which an artificial tumor was attached. Radiation dose assessment used CTDI value, while image quality assessment used noise and CNR. Data processing was conducted using linear regression test.Results: There was an effect of tube voltage setting and SAFIRE setting on radiation dose and image quality.Conclusions: Tube voltage ssetting and SAFIRE setting had an effect on radiation dose and image quality. Tube voltage setting and SAFIRE strength level setting that were able to provide optimal radiation dose and image quality were tube voltage of 80 kVp and SAFIRE strength levels 3 and 4 (S3 and S4). 

scholarly journals The Impact of Varying Number of OSEM Iterations on Standardized Uptake Value and Image Quality of Discovery STE PET/CT Scanner

2018 ◽  
Vol 4 (Supplement 2) ◽  
pp. 68s-68s
Author(s):  
B. Ali ◽  
A. Afshan ◽  
M.B. Kakakhel
Keyword(s):  
Image Quality ◽  
Standardized Uptake Value ◽  
Acquisition Time ◽  
List Mode ◽  
Ct Scanner ◽  
Matrix Size ◽  
Cold Lesion ◽  
Pet Ct ◽  
The Impact

Background: In PET imaging both quantitative and qualitative interpretations are used. Qualitative and quantitative interpretations depend upon PET/CT image quality that along with many biologic factors strongly depends upon image reconstruction parameters. Aim: The objective of this experimental work was to study the impact of one of the key reconstruction parameter, i.e., number of reconstruction iteration, on standardized uptake value and image quality of PET/CT scan. Methods: Images of NEMA IEC Image Quality Phantom were acquired in list mode for 10 mins on Discovery STE PET/CT scanner, using tumor to background ratio of 4:1 and 18F-FDG as radiotracer. List mode data were further transformed into data sets of varying acquisition time (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 mins) per bed position. Transformed data set of 5.0 mins were used to study the impact of varying number of iterations (2, 3, 4, 5, 7, 10, 15, 20) using OSEM approach of iterative reconstruction. Standardized uptake value (SUV) and underestimation in SUV were calculated as quantitative measures, while hot lesion contrast, cold lesion contrast and background variability were calculated as qualitative measures. Results: Standardized uptake value, hot and cold lesion contrast, image spatial resolution and background variability showed increasing trend with increase in reconstruction iterations. Maximum increase of 20.25%, 16.33%, 9.79% and 6.88% was observed in SUV for 10 mm, 13 mm, 17 mm and 22 mm lesions as number of iteration change from 2 to 3. Smallest and the largest diameter lesions showed maximum underestimations of 54.67% and 8.20% at 2 iterations respectively. Percentage hot lesion contrast showed rapid increase as the number of iteration change from 2 to 7 and increased slowly afterward. Background variability range from 4.4% to 6.4%, 4.1%–5.7%, 3.6%–4.6%, 3%–3.8%, 2.7%–3.2%, 2.4%–2.7% for 10.0 mm, 13.0 mm, 17.0 mm, 22.0 mm, 28.0 mm and 37.0 mm sphere respectively. Conclusion: Optimized reconstruction parameters for routine clinical studies 3 iterations with image matrix size of 128 × 128 with filters FWHM of 6 mm and for high resolution studies 3 iterations image matrix size of 256×256 with filters FWHM of 6 mm.

scholarly journals Paediatric head computed tomography dose values and the impact on image quality

2021 ◽  
Vol 31 (Supplement_2) ◽  
Author(s):  
Rafaela Meneses ◽  
Bruno Dias ◽  
Andrea Pimenta ◽  
Graciano Paulo ◽  
Joana Santos
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Image Quality Assessment ◽  
Ct Scanner ◽  
Reference Levels ◽  
Acquisition Mode ◽  
Paediatric Age ◽  
Computed Tomography Dose Index ◽  
The Impact ◽  
Head Computed Tomography

Abstract Background The purpose of this study is to analyse paediatric head Computed Tomography (CT) examination dose values, establish local Diagnostic Reference Levels (DRL), and perform objective image quality assessment per categorisation. Methods A total of 100 paediatric head CT examinations divided into 5 paediatric age categorisations were retrospectively selected: 0–3months, 3months to 1 year, 1 to 6 years, and more than 6 years. Computed Tomography Dose Index (CTDIvol - mGy) and Dose Lenght Product (DLP – mGy.cm), acquisition mode and CT scanner were collected per examination. Examinations with lower and higher dose values per categorisation were selected, and 10 Regions of Interest (ROI’s) were defined on supra and infra tentorial regions in order to access image quality, based on signal and noise values. Local DRLs were compare with the literature and with previous studies of this centre. Results The obtained DLP values were 580, 570, 700, 754 mGy.cm, for the categorisation of 0–3 months, 3 months to 1 year, 1 to 6 years, and more than 6 years, respectively. No significant differences were founded in dose values and image quality, per paediatric categorisation. Conclusions Despise previous local DRLs were defined using a different age categorisation, some paediatric aged categorisation revealed an increase of the dose values. These results must be related with the acquisition of a new CT scanner. Optimisation process is on-going and new protocols are being define.

Intraoperative computed tomography angiography with computed tomography perfusion imaging in vascular neurosurgery: feasibility of a new concept

2010 ◽  
Vol 112 (4) ◽  
pp. 722-728 ◽  
Author(s):  
Christian Schichor ◽  
Walter Rachinger ◽  
Dominik Morhard ◽  
Stefan Zausinger ◽  
Thomas J. Heigl ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Ct Angiography ◽  
Brain Perfusion ◽  
Acquisition Time ◽  
Data Sets ◽  
Ct Scanner ◽  
Intraoperative Ct ◽  
Vascular Neurosurgery ◽  
The Impact

Object In vascular neurosurgery, there is a demand for intraoperative imaging of blood vessels as well as for rapid information about critical impairment of brain perfusion. This study was conducted to analyze the feasibility of intraoperative CT angiography and brain perfusion mapping using an up-to-date multislice CT scanner in a prospective pilot series. Methods Ten patients with unruptured aneurysms underwent intraoperative scanning with a 40-slice sliding-gantry CT scanner. Multimodal CT acquisition was obtained in 8 patients consisting of dynamic perfusion CT (PCT) scanning followed by intracranial CT angiography. Two of these patients underwent CT angiography and PCT 2 times in 1 session as a control after repositioning cerebral aneurysm clips. In another 2 patients, CT angiography was performed alone. The quality of all imaging obtained was assessed in a blinded consensus reading performed by an experienced neurosurgeon and an experienced neuroradiologist. A 6-point scoring system ranging from excellent to insufficient was used for quality evaluation of PCT and CT angiography. Results In 9 of 10 PCT data sets, the quality was rated excellent or good. In the remaining case, the quality was rated insufficient for diagnostic evaluation due to major streak artifacts induced by the titanium pins of the head clamp. In this particular case, the quality of the related CT angiography was rated good and sufficient for intraoperative decision making. The quality of all 12 CT angiography data sets was rated excellent or good. In 1 patient with an anterior communicating artery aneurysm, PCT scanning led to a repositioning of the clip because of an ischemic pattern of the perfusion parameter maps due to clip stenosis of an artery. The subsequent PCT scan obtained in this patient revealed an improved perfusion of the related vascular territory, and follow-up MR imaging showed only minor ischemia of the anterior cerebral artery territory. Conclusions Intraoperative CT angiography and PCT scanning were shown to be feasible with short acquisition time, little interference with the surgical workflow, and very good diagnostic imaging quality. Thus, these modalities might be very helpful in vascular neurosurgery. Having demonstrated their feasibility, the impact of these methods on patients' outcomes has now to be analyzed prospectively in a larger series.

scholarly journals Impact and cost-effectiveness evaluation of a community-based rehabilitation intervention on quality of life among Chinese adults with hearing loss: study protocol for a randomized controlled trial

Trials ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xin Ye ◽  
Dawei Zhu ◽  
Siyuan Chen ◽  
Xuefeng Shi ◽  
Rui Gong ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Hearing Loss ◽  
Cost Effectiveness ◽  
Treatment Group ◽  
Hearing Aids ◽  
Control Group ◽  
Chinese Adults ◽  
Community Based ◽  
The Impact

Abstract Background Hearing loss is quite prevalent and can be related to people’s quality of life. To our knowledge, there are limited studies assessing the efficacy of hearing interventions on quality of life in adults. Therefore, we aim to conduct a randomized controlled trial (RCT) to determine the impact and cost-effectiveness of community-based hearing rehabilitation on quality of life among Chinese adults with hearing loss. Methods/design In this two-arm feasibility study, participants aged 16 and above with some degree of hearing loss (n = 464) will be recruited from Linyi City, Shandong Province. They are randomly assigned to the treatment group or the control group. Those in the treatment group are prescribed with hearing aids, while those in the control group receive no intervention. Reinstruction in use of devices is provided for the treatment group during booster visits held 12 months post-randomization or unscheduled interim visits when necessary. Data are collected at baseline and the follow-up 20 months later. The primary outcome is changes in quality of life over a 20-month study period. Secondary outcomes include sub-dimensions in quality of life, physical functioning, chronic diseases, cognitive function, depression, social support, hospitalizations, falls, and healthcare costs. Finally, we will evaluate whether hearing aids intervention is cost-effective to apply in a large scale. Discussion The trial is designed to evaluate the impact and cost-effectiveness of a community-based rehabilitation intervention on quality of life among Chinese adults with hearing loss. We hope that it would help improve the well-being for Chinese adults and provide references in policy and practice for China and other countries. Trial registration Chinese Clinical Trial Registry ChiCTR1900024739. Registered on 26 July 2019.

scholarly journals Modeling and image quality enhancement for dynamic compressive imaging system

2021 ◽  
Vol 15 ◽  
pp. 174830262110080
Author(s):  
Changjun Zha* ◽  
Qian Zhang* ◽  
Huimin Duan
Keyword(s):  
Image Quality ◽  
Imaging System ◽  
Quality Enhancement ◽  
Target Image ◽  
Compressive Imaging ◽  
Image Quality Enhancement ◽  
System A ◽  
Single Column ◽  
The Impact

Traditional single-pixel imaging systems are aimed mainly at relatively static or slowly changing targets. When there is relative motion between the imaging system and the target, sizable deviations between the measurement values and the real values can occur and result in poor image quality of the reconstructed target. To solve this problem, a novel dynamic compressive imaging system is proposed. In this system, a single-column digital micro-mirror device is used to modulate the target image, and the compressive measurement values are obtained for each column of the image. Based on analysis of the measurement values, a new recovery model of dynamic compressive imaging is given. Differing from traditional reconstruction results, the measurement values of any column of vectors in the target image can be used to reconstruct the vectors of two adjacent columns at the same time. Contingent upon characteristics of the results, a method of image quality enhancement based on an overlapping average algorithm is proposed. Simulation experiments and analysis show that the proposed dynamic compressive imaging can effectively reconstruct the target image; and that when the moving speed of the system changes within a certain range, the system reconstructs a better original image. The system overcomes the impact of dynamically changing speeds, and affords significantly better performance than traditional compressive imaging.

scholarly journals Evaluation of Organ Dose and Image Quality Metrics of Pediatric CT Chest-Abdomen-Pelvis (CAP) Examination: An Anthropomorphic Phantom Study

2021 ◽  
Vol 11 (5) ◽  
pp. 2047
Author(s):  
Nor Azura Muhammad ◽  
Zunaide Kayun ◽  
Hasyma Abu Hassan ◽  
Jeannie Hsiu Ding Wong ◽  
Kwan Hoong Ng ◽  
...  
Keyword(s):  
Image Quality ◽  
Multidetector Ct ◽  
Organ Dose ◽  
Quality Metrics ◽  
Ct Scanner ◽  
Image Quality Metrics ◽  
Tube Current ◽  
Significant Difference ◽  
Noise Ratio ◽  
The Impact

The aim of this study is to investigate the impact of CT acquisition parameter setting on organ dose and its influence on image quality metrics in pediatric phantom during CT examination. The study was performed on 64-slice multidetector CT scanner (MDCT) Siemens Definition AS (Siemens Sector Healthcare, Forchheim, Germany) using various CT CAP protocols (P1–P9). Tube potential for P1, P2, and P3 protocols were fixed at 100 kVp while P4, P5, and P6 were fixed at 80 kVp with used of various reference noise values. P7, P8, and P9 were the modification of P1 with changes on slice collimation, pitch factor, and tube current modulation (TCM), respectively. TLD-100 chips were inserted into the phantom slab number 7, 9, 10, 12, 13, and 14 to represent thyroid, lung, liver, stomach, gonads, and skin, respectively. The image quality metrics, signal to noise ratio (SNR) and contrast to noise ratio (CNR) values were obtained from the CT console. As a result, this study indicates a potential reduction in the absorbed dose up to 20% to 50% along with reducing tube voltage, tube current, and increasing the slice collimation. There is no significant difference (p > 0.05) observed between the protocols and image metrics.

New Approaches to Reduce Radiation While Maintaining Image Quality in Multi-Detector-Computed Tomography

2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Juan C. Ramirez-Giraldo ◽  
Matthew Fuld ◽  
Katharine Grant ◽  
Andrew N. Primak ◽  
Thomas Flohr
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
New Approaches ◽  
Multi Detector Computed Tomography

scholarly journals Novel Assistive Device for Tomographic Ultrasound Neck Imaging vs. Freehand

2020 ◽  
Vol 6 (3) ◽  
pp. 28-31
Author(s):  
Marcel Köhler ◽  
Elmer Jeto Gomes Ataide ◽  
Jens Ziegle ◽  
Axel Boese ◽  
Michael Friebe
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Diagnostic Procedures ◽  
Assistive Device ◽  
Volume Data ◽  
Data Set ◽  
Scanning Method ◽  
Neck Area ◽  
2D Ultrasound

AbstractFor assessing clinically relevant structures in the neck area, especially the thyroid, it has been shown that 3D or tomographic ultrasound (3D US or tUS) is able to outperform standard 2D ultrasound [1] and computed tomography [2] for certain diagnostic procedures. However, when using a freehand and unassisted scanning method to acquire a 3D US volume data set in this area overlapping image slices, a variation of the probe angulation or differences in training might lead to unusable scanning results. Based on previous works [3] [4] we propose the design - with subsequent testing - of an assistive device that is able to aid physicians during the tUS scanning process on the neck. To validate the feasibility and efficacy we compared the image quality of both freehand and assisted scanning.

Sign in / Sign up

Export Citation Format

Share Document