scholarly journals Image quality is resilient against tube voltage variations in post-mortem skeletal radiography with a digital flat-panel detector

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Notohamiprodjo ◽  
K. M. Roeper ◽  
K. M. Treitl ◽  
B. Hoberg ◽  
F. Wanninger ◽  
...  
Keyword(s):  
Image Quality ◽  
Patient Exposure ◽  
Signal To Noise ◽  
Flat Panel ◽  
Tube Voltage ◽  
Low Contrast ◽  
Body Regions ◽  
Human Cadavers ◽  
Skeletal Radiography ◽  
Phantom Studies

AbstractIn recent phantom studies low-contrast detectability was shown to be independent from variations in tube voltage in digital radiography (DR) systems. To investigate the transferability to a clinical setting, the lower extremities of human cadavers were exposed at constant detector doses with different tube voltages in a certain range, as proposed in the phantom studies. Three radiologists independently graded different aspects of image quality (IQ) in a comparative analysis. The grades show no correlation between IQ and kV, which means that the readers were not able to recognize a significant IQ difference at different kV. Signal-to-noise and contrast-to-noise ratios showed no significant differences in IQ despite the kV-setting variations. These findings were observed from a limited kV range setting. Higher kV-settings resulted in lowest patient exposure at constant IQ. These results confirm the potential of DR-systems to contribute to standardization of examination protocols comparable to computed tomography. This may prevent the trend to overexpose. Further investigations in other body regions and other DR-systems are encouraged to determine transferability.

Improvement of image quality applying iterative scatter correction for grid-less skeletal radiography in trauma room setting

2019 ◽  
Vol 61 (6) ◽  
pp. 768-775
Author(s):  
Christoph G Lisson ◽  
Catharina S Lisson ◽  
Daniel Vogele ◽  
Beatrice Strauss ◽  
Konrad Schuetze ◽  
...  
Keyword(s):  
Image Quality ◽  
Rating Scale ◽  
Scatter Correction ◽  
Iterative Algorithms ◽  
Trauma Room ◽  
Body Regions ◽  
Wide Range ◽  
Characteristics Analysis ◽  
Skeletal Radiography ◽  
The Future Method

Background Iterative reconstruction is well established for CT. Plain radiography also takes advantage of iterative algorithms to reduce scatter radiation and improve image quality. First applications have been described for bedside chest X-ray. A recent experimental approach also provided proof of principle for skeletal imaging. Purpose To examine clinical applicability of iterative scatter correction for skeletal imaging in the trauma setting. Material and Methods In this retrospective single-center study, 209 grid-less radiographs were routinely acquired in the trauma room for 12 months, with imaging of the chest (n = 31), knee (n = 111), pelvis (n = 14), shoulder (n = 24), and other regions close to the trunk (n = 29). Radiographs were postprocessed with iterative scatter correction, doubling the number of images. The radiographs were then independently evaluated by three radiologists and three surgeons. A five-step rating scale and visual grading characteristics analysis were used. The area under the VGC curve (AUCVGC) quantified differences in image quality. Results Images with iterative scatter correction were generally rated significantly better (AUCVGC = 0.59, P < 0.01). This included both radiologists (AUCVGC = 0.61, P < 0.01) and surgeons (AUCVGC = 0.56, P < 0.01). The image-improving effect was significant for all body regions; in detail: chest (AUCVGC = 0.64, P < 0.01), knee (AUCVGC = 0.61, P < 0.01), pelvis (AUCVGC = 0.60, P = 0.01), shoulder (AUCVGC = 0.59, P = 0.02), and others close to the trunk (AUCVGC = 0.59, P < 0.01). Conclusion Iterative scatter correction improves the image quality of grid-less skeletal radiography in the clinical setting for a wide range of body regions. Therefore, iterative scatter correction may be the future method of choice for free exposure imaging when an anti-scatter grid is omitted due to high risk of tube-detector misalignment.

scholarly journals Studies on the radiation dose, image quality and low contrast detectability from MSCT abdomen by using low tube voltage

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
A. Mokhtar ◽  
Z. A. Aabdelbary ◽  
A. Sarhan ◽  
H. M. Gad ◽  
M. T. Ahmed
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Statistical Significance ◽  
Image Noise ◽  
Tube Voltage ◽  
Current Time ◽  
Low Contrast ◽  
Low Tube Voltage ◽  
Tube Current ◽  
Noise Ratio

Abstract Background To study radiation dose, image quality and low-contrast cylinder detectability from multislice CT (MSCT) abdomen by using low tube voltage using the American College of Radiology (ACR) phantom. The ACR phantom (low-contrast module) was scanned with 64 MSCT scanner (Brilliance, Philips Medical System, Eindhoven, Netherlands) with 80 and 120 KVP, utilizing different tube current time product (mAs) range from 50 to 380 mAs. The image noise (SD), signal to noise ratio, contrast-to-noise ratio (CNR), and scores of low contrast detectability were assessed for every image respectively. Results From images analyses, the noise essentially increased with the use of low tube voltage. The CNR was 0.94 ± 0.27 at 120 KVP, and CNR was 0.43 ± 0.22 at 80 KVP. However, with the same dose, there were no differences of statistical significance in scores of low-contrast detectability between 120 KVP at 300mAs and 80 KVP at (200–380) mAs (p > 0.05). At 300 mAs, the CTDIvol obtained at 80 KVP was about 29% of that at 120 KVP. The CTDIvol obtained at 80 KVP were decreased from 5% at 50 mAs, to 37% at 380 mAs. Conclusions There is a possibility to decrease exposure of radiation virtually by reducing KVP from 120 to 80 KVP in examination of abdominal CT when the high tube current is used, though increasing image noise at low tube voltage.

Diagnostic performance and image quality of low-tube voltage and low-contrast medium dose protocol with hybrid iterative reconstruction for hepatic dynamic CT

2021 ◽  
Author(s):  
Shintaro Ichikawa ◽  
Utaroh Motosugi ◽  
Tatsuya Shimizu ◽  
Marie Luise Kromrey ◽  
Yoshihito Aikawa ◽  
...  
Keyword(s):  
Image Quality ◽  
Iterative Reconstruction ◽  
Diagnostic Performance ◽  
Dynamic Ct ◽  
Diagnostic Ability ◽  
Tube Voltage ◽  
Low Contrast ◽  
Lesion Detectability ◽  
Hybrid Iterative Reconstruction

Objective: To evaluate the diagnostic performance and image quality of the low-tube voltage and low-contrast medium dose protocol for hepatic dynamic CT. Methods: This retrospective study was conducted between January and May 2018. All patients underwent hepatic dynamic CT using one of the two protocols: tube voltage, 80 kVp and contrast dose, 370   mgI/kg with hybrid iterative reconstruction or tube voltage, 120 kVp and contrast dose, 600  mgI/kg with filtered back projection. Two radiologists independently scored lesion conspicuity and image quality. Another radiologist measured the CT numbers of abdominal organs, muscles, and hepatocellular carcinoma (HCC) in each phase. Lesion detectability, HCC diagnostic ability, and image quality of the arterial phase were compared between the two protocols using the non-inferiority test. CT numbers and HCC-to-liver contrast were compared between the protocols using the Mann–Whitney U test. Results: 424 patients (70.5 ± 10.1 years) were evaluated. The 80-kVp protocol showed non-inferiority in lesion detectability and diagnostic ability for HCC (sensitivity, 85.7–89.3%; specificity, 96.3–98.6%) compared with the 120-kVp protocol (sensitivity, 91.0–93.3%; specificity, 93.6–97.3%) (p < 0.001–0.038). The ratio of fair image quality in the 80-kVp protocol also showed non-inferiority compared with that in the 120-kVp protocol in assessments by both readers (p < 0.001). HCC-to-liver contrast showed no significant differences for all phases (p = 0.309–0.705) between the two protocols. Conclusion: The 80-kVp protocol with hybrid iterative reconstruction for hepatic dynamic CT can decrease iodine doses while maintaining diagnostic performance and image quality compared with the 120-kVp protocol. Advances in knowledge: The 80- and 120-kVp protocols showed equivalent hepatic lesion detectability, diagnostic ability for HCC, image quality, and HCC-to-liver contrast. The 80-kVp protocol showed a 38.3% reduction in iodine dose compared with the 120-kVp protocol.

Dependence of low contrast detail on exposure dose and tube voltage in digital flat-panel detector radiography—a pre-clinical phantom study

2018 ◽  
Vol 4 (2) ◽  
pp. 025010
Author(s):  
S Notohamiprodjo ◽  
L Verstreepen ◽  
F Wanninger ◽  
B Hoberg ◽  
K M Röper ◽  
...  
Keyword(s):  
Exposure Dose ◽  
Phantom Study ◽  
Flat Panel ◽  
Tube Voltage ◽  
Low Contrast ◽  
Flat Panel Detector
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