scholarly journals Effectiveness of low-tube current for reducing radiation dose in cerebral CT perfusion

2021 ◽  
Author(s):  
Chao Tian ◽  
Tian-hao Yang ◽  
Le-jun Fu ◽  
Song Jin
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Cerebral Blood Volume ◽  
Ct Perfusion ◽  
Signal To Noise Ratio ◽  
Mean Transit Time ◽  
Noise Signal ◽  
Maximum Enhancement ◽  
Dose Length Product ◽  
Tube Current

IntroductionObjective: This study aims to investigate the reduction of radiation dose in cerebral CT perfusion by lower low-tube current.Material and methodsTwo hundred patients, who underwent cerebral non-contrast computed tomography (CT) and CT perfusion, were randomized into four groups according to tube current and contrast media (CM) concentration: group A (60 mAs, 320 mgI/ml), group B (60 mAs, 370 mgI/ml), group C (100 mAs, 320 mgI/ml), and group D (100 mAs, 370 mgI/ml). Among these four groups, the CT dose index (CTDIvol), dose length product (DLP) and effective dose (ED) was calculated. The quantitative image comparison included maximum enhancement, noise, signal-to-noise ratio (SNR), cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) from five regions of interests (ROIs).ResultsRanging from 100 mAs to 60 mAs, groups A and B achieved 40% lower CTDIvol, DLP and ED, when compared with groups C and D. Both the maximum enhancement and noise of all ROIs were higher in groups A and B, when compared to groups C and D (P<0.05). The CBV values were higher in groups B and D, when compared to groups A and C (P<0.05). The image quality (IQ) of each group of perfusion maps met the requirements for imaging diagnosis.ConclusionsThe reduction in tube current from 100 mAs to 60 mAs for cerebral CT perfusion led to a 40% reduction in radiation dose without sacrificing image quality.

scholarly journals Variation in tube voltage for pediatric neck 64VCT: Effect on radiation dose and image quality

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259772
Author(s):  
Li-Guo Chen ◽  
Ping-An Wu ◽  
Hsing-Yang Tu ◽  
Ming-Huei Sheu ◽  
Li-Chuan Huang
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Region Of Interest ◽  
Ct Scanner ◽  
Multidetector Row Ct ◽  
Dose Length Product ◽  
Multidetector Row ◽  
Tube Current ◽  
Noise Measurements ◽  
Unpaired Student

Exposure to ionizing radiation can cause cancer, especially in children. In computed tomography (CT), a trade-off exists between the radiation dose and image quality. Few studies have investigated the effect of dose reduction on image quality in pediatric neck CT. We aimed to assess the effect of peak kilovoltage on the radiation dose and image quality in pediatric neck multidetector-row CT. Measurements were made using three phantoms representative of children aged 1, 5, and 10 years, with tube voltages of 80, 100, and 120 kilovoltage peak (kVp); tube current of 10, 40, 80, 120, 150, 200, and 250 mA; and exposure time = 0.5 s (pitch, 0.984:1). Radiation dose estimates were derived from the dose-length product with a 64-multidetector-row CT scanner. Images obtained from the control protocol (120 kVp) were compared with the 80- and 100-kVp protocols. The effective dose (ED) was determined for each protocol and compared with the 120-kVp protocol. Quantitative analysis entailed noise measurements by recording the standard deviation of attenuation for a circular 1-cm2 region of interest placed on homogeneous soft tissue structures in the phantom. The mean noise of the various kVp protocols was compared using the unpaired Student t-test. Reduction of ED was 37.58% and 68.58% for neck CT with 100 kVp and 80 kVp, respectively. The image noise level increased with the decrease in peak kilovoltage. Noise values were higher at 80 kVp at all neck levels, but did not increase at 100 kVp, compared to 120 kVp in the three phantoms. The measured noise difference was the greatest at 80 kVp (absolute increases<2.5 HU). The subjective image quality did not differ among the protocols. Thus, reducing voltage from 120 to 80 kVp for neck CT may achieve ED reduction of 68.58%, without compromising image quality.

scholarly journals Influence of Image Acquisition on Radiation Dose and Image Quality: Full versus Narrow Phase Window Acquisition Using 320 MDCT

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Faisal Khosa ◽  
Atif Khan ◽  
Khurram Nasir ◽  
Waqas Shuaib ◽  
Matthew Budoff ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Ordinal Scale ◽  
Diagnostic Image Quality ◽  
Dose Length Product ◽  
Diagnostic Image ◽  
Lower Radiation Dose ◽  
Tube Current ◽  
Dose Modulation ◽  
Mean Heart Rate

Purpose. To compare radiation dose and image quality using predefined narrow phase window versus complete phase window with dose modulation during R-R using 320-row MDCTA.Methods. 114 patients underwent coronary CTA study using 320-row MDCT scanner. 87 patients with mean age (61 + 13 years), mean BMI (29 + 6), and mean heart rate (HR) (58 + 7 bpm) were imaged at predefined 66–80% R-R interval and then reconstructed at 75% while 27 patients with mean age (63 + 16 years), mean BMI (28 + 5), and mean HR (57 + 7 bpm) were scanned throughout the complete R-R interval with tube current modulation. The effective dose (ED) was calculated from dose length product (DLP) and conversionk(0.014 mSv/mGy/cm). Image quality was assessed using a three-point ordinal scale (1 = excellent, 2 = good, and 3 = nondiagnostic).Results. Both groups were statistically similar to each other with reference of HR (P=0.59), BMI (P=0.17), and tube current mAs (P=0.68). The median radiation dose was significantly higher in those scanned with complete R-R phase window versus narrow phase window (P<0.0001). Independently of patient and scan parameters, increased phase window was associated with higher radiation dose (P<0.001). Image quality was better among those scanned with narrow phase window versus complete phase window (P<0.0001).Conclusion. Our study supports that good HR control and predefined narrow window acquisition result in lower radiation dose without compromising diagnostic image quality for coronary disease evaluation.

scholarly journals Pengaruh Tegangan Tabung terhadap Kualitas Citra pada Pemeriksaan Computed Tomography Kepala menggunakan Iterative Reconstruction

2021 ◽  
Vol 9 (1) ◽  
pp. 103-110
Author(s):  
Muhammad Irsal ◽  
◽  
Nurbaiti Nurbaiti ◽  
Aulia Narendra Mukhtar ◽  
Shinta Gunawati ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Effective Dose ◽  
Iterative Reconstruction ◽  
Signal To Noise Ratio ◽  
Hounsfield Unit ◽  
P Value ◽  
Dose Length Product ◽  
Reconstruction Image

Iterative reconstruction can optimize radiation dose and improve image quality on CT scan. This research method is quantitative analytic with the analysis of the results of the head CT examination parameters associated with image quality to changes in variations of 80 kV, 100 kV, 120 kV with the use of iterative reconstruction. Image quality measurements are the Hounsfield Unit (HU) value, standard deviation, and Signal to Noise Ratio (SNR) using Radiant Viewers. Effective dose measurement using the Dose Length Product (DLP). Then perform the Kruskal Wallis test to find out whether there is an effect of tube voltage and Iterative Reconstruction on the SNR value using IBM SPSS version 24. The results image quality of the HU value increase due to changes in the kV value, but the value does not change significantly when the iDose changes, for the standard The deviation has decreased due to changes in kV, but the value of the value does not experience a significant change at the time of change in iDose, while SNR increases due to changes in kV value and changes in iDose. The percentage ratio of the effective dose in the use of standard kV with 80 kV decreased radiation dose by 62%, while at 100 kV there was a decrease of 25%, and the use of 120 kV experienced an increase of 25%. The results of the Kruskal Wallis test p-value <0.001, therefore it can be concluded that there is a difference in the SNR image quality at each change in iDose and kV parameters.

scholarly journals Deep Learning Versus Iterative Reconstruction for CT Pulmonary Angiography in the Emergency Setting: Improved Image Quality and Reduced Radiation Dose

Diagnostics ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 558
Author(s):  
Marc Lenfant ◽  
Olivier Chevallier ◽  
Pierre-Olivier Comby ◽  
Grégory Secco ◽  
Karim Haioun ◽  
...  
Keyword(s):  
Deep Learning ◽  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Noise Signal ◽  
Pulmonary Angiography ◽  
Image Noise ◽  
Emergency Setting ◽  
Dose Length Product ◽  
Noise Ratio

To compare image quality and the radiation dose of computed tomography pulmonary angiography (CTPA) subjected to the first deep learning-based image reconstruction (DLR) (50%) algorithm, with images subjected to the hybrid-iterative reconstruction (IR) technique (50%). One hundred forty patients who underwent CTPA for suspected pulmonary embolism (PE) between 2018 and 2019 were retrospectively reviewed. Image quality was assessed quantitatively (image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR)) and qualitatively (on a 5-point scale). Radiation dose parameters (CT dose index, CTDIvol; and dose-length product, DLP) were also recorded. Ninety-three patients were finally analyzed, 48 with hybrid-IR and 45 with DLR images. The image noise was significantly lower and the SNR (24.4 ± 5.9 vs. 20.7 ± 6.1) and CNR (21.8 ± 5.8 vs. 18.6 ± 6.0) were significantly higher on DLR than hybrid-IR images (p < 0.01). DLR images received a significantly higher score than hybrid-IR images for image quality, with both soft (4.4 ± 0.7 vs. 3.8 ± 0.8) and lung (4.1 ± 0.7 vs. 3.6 ± 0.9) filters (p < 0.01). No difference in diagnostic confidence level for PE between both techniques was found. CTDIvol (4.8 ± 1.4 vs. 4.0 ± 1.2 mGy) and DLP (157.9 ± 44.9 vs. 130.8 ± 41.2 mGy∙cm) were lower on DLR than hybrid-IR images. DLR both significantly improved the image quality and reduced the radiation dose of CTPA examinations as compared to the hybrid-IR technique.

High-quality low-dose cardiovascular computed tomography (CCT) in pediatric patients using a 64-slice scanner

2018 ◽  
Vol 59 (10) ◽  
pp. 1247-1253 ◽  
Author(s):  
Paola Maria Cannaò ◽  
Francesco Secchi ◽  
Marco Alì ◽  
Ida Daniela D'Angelo ◽  
Marco Scarabello ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Effective Dose ◽  
Low Dose ◽  
Signal To Noise Ratio ◽  
High Quality ◽  
Dose Length Product ◽  
Noise Ratio ◽  
Estimate Radiation Dose

Background Cardiovascular computed tomography (CCT) technology is rapidly advancing allowing to perform good quality examinations with a radiation dose as low as 1.2 mSv. However, latest generation scanners are not available in all centers. Purpose To estimate radiation dose and image quality in pediatric CCT using a standard 64-slice scanner. Material and Methods A total of 100 patients aged 6.9 ± 5.4 years (mean ± standard deviation) who underwent a 64-slice CCT scan using 80, 100, or 120 kVp, were retrospectively evaluated. Radiation effective dose was calculated on the basis of the dose length product. Two independent readers assessed the image quality through signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and a qualitative score (3 = very good, 2 = good, 1 = poor). Non-parametric tests were used. Results Fifty-five exams were not electrocardiographically (ECG) triggered, 20 had a prospective ECG triggering, and 25 had retrospective ECG triggering. The median effective dose was 1.3 mSv (interquartile range [IQR] = 0.8–2.7 mSv). Median SNR was 30.6 (IQR = 23.4–33.6) at 120 kVp, 29.4 (IQR = 23.7–34.8) at 100 kVp, and 24.7 (IQR = 19.4–34.3) at 80 kVp. Median CNR was 21.0 (IQR = 14.8–24.4), 19.1 (IQR = 15.6–23.9), and 25.3 (IQR = 19.4–33.4), respectively. Image quality was very good, good, and poor in 56, 39, and 5 patients, respectively. No significant differences were found among voltage groups for SNR ( P = 0.486), CNR ( P = 0.336), and subjective image quality ( P = 0.296). The inter-observer reproducibility was almost perfect (κ = 0.880). Conclusion High-quality pediatric CCT can be performed using a 64-slice scanner, with a radiation effective dose close to 2 mSv in about 50% of the cases.

scholarly journals Implementation of ultra-low-dose lung protocols in CT-guided lung biopsies: feasibility and safety in the clinical setting

2017 ◽  
Vol 45 (6) ◽  
pp. 2101-2109 ◽  
Author(s):  
Barbara K Frisch ◽  
Karin Slebocki ◽  
Kamal Mammadov ◽  
Michael Puesken ◽  
Ingrid Becker ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Low Dose ◽  
Standard Dose ◽  
Complication Rates ◽  
Dose Length Product ◽  
Ct Guided ◽  
Total Radiation Dose ◽  
Lung Biopsies ◽  
Histological Results

Objective To evaluate the use of ultra-low-dose computed tomography (ULDCT) for CT-guided lung biopsy versus standard-dose CT (SDCT). Methods CT-guided lung biopsies from 115 patients (50 ULDCT, 65 SDCT) were analyzed retrospectively. SDCT settings were 120 kVp with automatic mAs modulation. ULDCT settings were 80 kVp with fixed exposure (20 mAs). Two radiologists evaluated image quality (i.e., needle artifacts, lesion contouring, vessel recognition, visibility of interlobar fissures). Complications and histological results were also evaluated. Results ULDCT was considered feasible for all lung interventions, showing the same diagnostic accuracy as SDCT. Its mean total radiation dose (dose–length product) was significantly reduced to 34 mGy-cm (SDCT 426 mGy-cm). Image quality and complication rates ( P = 0.469) were consistent. Conclusions ULDCT for CT-guided lung biopsies appears safe and accurate, with a significantly reduced radiation dose. We therefore recommend routine clinical use of ULDCT for the benefit of patients and interventionalists.

scholarly journals Feasible Dose Reduction in Routine Chest Computed Tomography Maintaining Constant Image Quality Using the Last Three Scanner Generations: From Filtered Back Projection to Sinogram-affirmed Iterative Reconstruction and Impact of the Novel Fully Integrated Detector Design Minimizing Electronic Noise

2014 ◽  
Vol 4 ◽  
pp. 38 ◽  
Author(s):  
Lukas Ebner ◽  
Felix Knobloch ◽  
Adrian Huber ◽  
Julia Landau ◽  
Daniel Ott ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Radiation Dose ◽  
Dose Reduction ◽  
Integrated Circuit ◽  
Chest Ct ◽  
Back Projection ◽  
Dose Length Product ◽  
Chest Computed Tomography ◽  
Tube Current

Objective: The aim of the present study was to evaluate a dose reduction in contrast-enhanced chest computed tomography (CT) by comparing the three latest generations of Siemens CT scanners used in clinical practice. We analyzed the amount of radiation used with filtered back projection (FBP) and an iterative reconstruction (IR) algorithm to yield the same image quality. Furthermore, the influence on the radiation dose of the most recent integrated circuit detector (ICD; Stellar detector, Siemens Healthcare, Erlangen, Germany) was investigated. Materials and Methods: 136 Patients were included. Scan parameters were set to a thorax routine: SOMATOM Sensation 64 (FBP), SOMATOM Definition Flash (IR), and SOMATOM Definition Edge (ICD and IR). Tube current was set constantly to the reference level of 100 mA automated tube current modulation using reference milliamperes. Care kV was used on the Flash and Edge scanner, while tube potential was individually selected between 100 and 140 kVp by the medical technologists at the SOMATOM Sensation. Quality assessment was performed on soft-tissue kernel reconstruction. Dose was represented by the dose length product. Results: Dose-length product (DLP) with FBP for the average chest CT was 308 mGy*cm ± 99.6. In contrast, the DLP for the chest CT with IR algorithm was 196.8 mGy*cm ± 68.8 (P = 0.0001). Further decline in dose can be noted with IR and the ICD: DLP: 166.4 mGy*cm ± 54.5 (P = 0.033). The dose reduction compared to FBP was 36.1% with IR and 45.6% with IR/ICD. Signal-to-noise ratio (SNR) was favorable in the aorta, bone, and soft tissue for IR/ICD in combination compared to FBP (the P values ranged from 0.003 to 0.048). Overall contrast-to-noise ratio (CNR) improved with declining DLP. Conclusion: The most recent technical developments, namely IR in combination with integrated circuit detectors, can significantly lower radiation dose in chest CT examinations.

Abstract 2619: Autoregulation of Cerebral Blood Flow is Preserved in Primary Intracerebral Hemorrhage

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
E B Gould ◽  
Rebecca McCourt ◽  
Sana Vahidy ◽  
Negar Asdaghi ◽  
Michael D Hill ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Intracerebral Hemorrhage ◽  
Cerebral Autoregulation ◽  
Cerebral Blood Volume ◽  
Ct Perfusion ◽  
Mean Transit Time ◽  
Serial Ct ◽  
Acute Intracerebral Hemorrhage ◽  
Perfusion Maps

Background: Treatment of hypertension during acute intracerebral hemorrhage (ICH) is controversial. There are concerns that in the context of disrupted cerebral autoregulation, blood pressure (BP) reduction may cause decreased cerebral blood flow (CBF), particularly in the perihematoma region. CBF was assessed using serial CT perfusion (CTP) studies. We hypothesized that CBF would remain stable following BP reduction. Methods: Acute primary ICH patients were imaged pre and post BP treatment. Perfusion maps were calculated from CTP source images. Mean CBF was measured in a 1cm perihematoma region, contralateral homologous regions and in both hemispheres. Mean cerebral blood volume (CBV), mean transit time (MTT), and time to drain (TTD) were calculated in the same manner. Relative measures (i.e. rCBF) were calculated as ratios/differences between ipsilateral and contralateral regions. Results: Sixteen patients (median age 75 (54-91)) were imaged with CTP (median time from onset 19.4 (2.0-72.2) h) and re-imaged 2.0 (1.1-3.3) h later. Median NIHSS at baseline was 9 (2-24); this remained stable at the time of the second CTP (10 (2-24), P=0.14). Baseline hematoma volume was 24.8±19.9 ml and there was no change at the time of the second CTP (26.3±22.1 ml, P=0.16). Patients were recruited from an ongoing trial, in which they were randomly treated to a target systolic BP of <150mmHg (n=9) or <180mmHg (n=7). Four patients received no antihypertensives as BP was below target at the time of randomization. Mean systolic BP in treated patients (n=12) decreased significantly between the first (165±23 mmHg) and second (143±18 mmHg, P<0.0001) CTP scans. Mean perihematoma CBF in treated patients was stable with BP reduction (pre=35.1±7.1 vs. post=35.4±6.2 ml/100g/min, P=0.87). Ipsilateral hemispheric CBF was also stable (pre=47.3±7.2 vs. post=46.4±7.1 ml/100g/min, P=0.66). Although perihematoma CBF was lower than in contralateral homologous regions (rCBF=0.72±0.11), BP reduction did not decrease this further (0.74±0.14 post-treatment, P=0.58). Ipsilateral hemispheric rCBF (0.96±0.06) was also unaffected by BP treatment (0.95±0.08, P=0.64). Perihematoma rCBF decreased in 5 treated patients, but never by >12%. Linear regression showed no relationship between changes in systolic BP and perihematoma rCBF (R=-0.002, [-0.005, 0.001], P=0.18). Perihematoma rCBV (pre=0.77±0.11 vs. post=0.79±0.10, P=0.20), rMTT (pre=0.51±0.54s vs. post=0.70±0.65s, P=0.26) and rTTD (pre=0.71±1.01s vs. post=0.89±0.84s, P=0.42) also remained stable following BP treatment. Conclusions: Acute BP reduction does not appear to exacerbate perihematoma oligaemia. Stability of CBF following acute BP treatment suggests preservation of cerebral autoregulation in ICH, within the range of arterial pressures studied. These findings support the safety of early BP treatment in ICH.

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