1,721,145 research outputs found
Intra-individual radiomic analysis of pericoronary adipose tissue: photon-counting detector vs energy-integrating detector CT angiography
No full textBackground: The impact of novel photon-counting detector (PCD)-CT technology on in-vivo radiomics is not fully understood. This study aimed to compare the intra-individual stability and reproducibility of pericoronary adipose tissue (PCAT) radiomic features between PCD-CT and energy-integrating detector (EID)-CT in patients undergoing coronary CT angiography (CCTA) on both systems. Methods: Patients undergoing clinically indicated CCTA on an EID-CT were prospectively enrolled for research PCD-CCTA within 30 days. Image acquisition parameters were standardized; PCD-CT datasets were reconstructed both down-sampled to 0.6 mm to match the clinical scan (PCD-CTDS) and at 0.2 mm ultrahigh-resolution mode (PCD-CTUHR). Automatic PCAT segmentation was performed; a total of 110 radiomic feature classes were extracted and compared across the three datasets (EID-CT, PCD-CTDS, and PCD-CDUHR). Feature stability was assessed using paired t-test filtered for false discoveries using Benjamini–Hochberg method, and reproducibility using intraclass correlation coefficient (ICC). Results: A total of 42 patients (34 male [81.0 %]; 67.9 ± 7.6 years) were included. Feature stability was 91 % for EID-CT vs. PCD-CTDS, but decreased for UHR datasets (EID-CT vs. PCD-CTUHR: 55 %; PCD-CTDS vs. PCD-CTUHR: 51 %). However, inter-scanner reproducibility was poor in both comparisons (EID-CT vs. PCD-CTDS median ICC: 0.43 [0.03–0.69]; EID-CT vs. PCD-CTUHR: 0.29 [0.01–0.51]). Nevertheless, reproducibility improved within PCD-CT datasets (PCD-CTDS vs. PCD-CTUHR: 0.72 [0.48–0.83]), regardless of the difference in slice thickness. Conclusions: Most PCAT radiomic features remained stable between EID-CT and PCD-CTDS, although inter-scanner reproducibility was poor, emphasizing the significant impact of detector technology. Conversely, reproducibility of features within PCD-CT datasets showed more consistent results, even when comparing standard to UHR
Intraindividual reproducibility of myocardial radiomic features between energy-integrating detector and photon-counting detector CT angiography
Full text linkBackgroundRadiomics is not yet used in clinical practice due to concerns regarding its susceptibility to technical factors. We aimed to assess the stability and interscan and interreader reproducibility of myocardial radiomic features between energy-integrating detector computed tomography (EID-CT) and photon-counting detector CT (PCD-CT) in patients undergoing coronary CT angiography (CCTA) on both systems.MethodsConsecutive patients undergoing clinically indicated CCTA on an EID-CT were prospectively enrolled for a PCD-CT CCTA within 30 days. Virtual monoenergetic images (VMI) at various keV levels and polychromatic images (T3D) were generated for PCD-CT, with image reconstruction parameters standardized between scans. Two readers performed myocardial segmentation and 110 radiomic features were compared intraindividually between EID-CT and PDC-CT series. The agreement of parameters was assessed using the intraclass correlation coefficient and paired t-test for the stability of the parameters.ResultsEighteen patients (15 males) aged 67.6 +/- 9.7 years (mean +/- standard deviation) were included. Besides polychromatic PCD-CT reconstructions, 60- and 70-keV VMIs showed the highest feature stability compared to EID-CT (96%, 90%, and 92%, respectively). The interscan reproducibility of features was moderate even in the most favorable comparisons (median ICC 0.50 [interquartile range 0.20-0.60] for T3D; 0.56 [0.33-0.74] for 60 keV; 0.50 [0.36-0.62] for 70 keV). Interreader reproducibility was excellent for the PCD-CT series and good for EID-CT segmentations.ConclusionMost myocardial radiomic features remain stable between EID-CT and PCD-CT. While features demonstrated moderate reproducibility between scanners, technological advances associated with PCD-CT may lead to greater reproducibility, potentially expediting future standardization efforts.Relevance statementWhile the use of PCD-CT may facilitate reduced interreader variability in radiomics analysis, the observed interscanner variations in comparison to EID-CT should be taken into account in future research, with efforts being made to minimize their impact in future radiomics studies.Key PointsMost myocardial radiomic features resulted in being stable between EID-CT and PCD-CT on certain VMIs.The reproducibility of parameters between detector technologies was limited.PCD-CT improved interreader reproducibility of myocardial radiomic features
Intra-individual comparison of epicardial adipose tissue characteristics on coronary CT angiography between photon-counting detector and energy-integrating detector CT systems
No full textPurpose: To explore the potential differences in epicardial adipose tissue (EAT) volume and attenuation measurements between photon-counting detector (PCD) and energy-integrating detector (EID)-CT systems. Methods: Fifty patients (mean age 69 +/- 8 years, 41 male [82 %]) were prospectively enrolled for a research coronary CT angiography (CCTA) on a PCD-CT within 30 days after clinical EID-based CCTA. EID-CT acquisitions were reconstructed using a Bv40 kernel at 0.6 mm slice thickness. The PCD-CT acquisition was reconstructed at a down-sampled resolution (0.6 mm, Bv40; [PCD-DS]) and at ultra-high resolutions (PCD-UHR) with a 0.2 mm slice thickness and Bv40, Bv48, and Bv64 kernels. EAT segmentation was performed semi-automatically at about 1 cm intervals and interpolated to cover the whole epicardium within a threshold of -190 to -30 HU. A subgroup analysis was performed based on quartile groups created from EID-CT data and PCD-UHRBv48 data. Differences were measured using repeated-measures ANOVA and the Friedman test. Correlations were tested using Pearson's and Spearman's rho, and agreement using Bland-Altman plots. Results: EAT volumes significantly differed between some reconstructions (e.g. EID-CT: 138 ml [IQR 100, 188]; PCD-DS: 147 ml [110, 206]; P<0.001). Overall, correlations between PCD-UHR and EID-CT EAT volumes were excellent, e.g. PCD-UHRBv48: r: 0.976 (95 % CI: 0.958, 0.987); P<0.001; with good agreement (mean bias: -9.5 ml; limits of agreement [LoA]: -40.6, 21.6). On the other hand, correlations regarding EAT attenuation was moderate, e.g. PCD-UHRBV48: r: 0.655 (95 % CI: 0.461, 0.790); P<0.001; mean bias: 6.5 HU; LoA: -2.0, 15.0. Conclusion: EAT attenuation and volume measurements demonstrated different absolute values between PCD-UHR, PCD-DS as well as EID-CT reconstructions, but showed similar tendencies on an intra-individual level. New protocols and threshold ranges need to be developed to allow comparison between PCD-CT and EID-CT data
Dynamic myocardial CT perfusion imaging
Full text linkThe few patient studies focusing on dynamic CTMPI for myocardial ischemia detection show promising results. Absolute quantification of perfusion parameters offers great potential, not only in the diagnosis of myocardial ischemia but potentially also in the detection of early signs of reduced myocardial blood flow as well as the diagnosis of microvascular disease and three-vessel disease. With the advent of new dose reduction techniques and new developments in CT systems, resulting in faster scanning times and wider detectors, clinical implementation of dynamic CTMPI becomes closer
Lung Cancer Screening: Evidence, Recommendations, and Controversies
No full textLung cancer causes the most cancer-related deaths worldwide. The incidence of lung cancer increases with age, and the most important risk factor is smoking. Smoking prevention and cessation programs have decreased the number of lung cancer cases. The overall prognosis of lung cancer remains poor, despite advances in treatment. The purpose of lung cancer screening is detecting malignancy at an earlier and curable stage. The National Lung Screening Trial demonstrated that early detection of lung cancer with low-dose computed tomography (LDCT) decreases mortality compared with screening by chest radiography. In the United States, several organizations published guidelines, recommending implementation of lung cancer screening for high-risk patients. However, some important questions regarding LDCT screening have so far been unanswered. The awaited results of the European trials and pooling of data will be crucial in establishing recommendations regarding clinical implementation of lung cancer screening in asymptomatic high-risk persons. This review presents an overview of current evidence, recommendations, and controversies concerning lung cancer screening.</p
Effect of automated tube voltage selection, integrated circuit detector and advanced iterative reconstruction on radiation dose and image quality of 3rd generation dual-source aortic CT angiography: an intra-individual comparison
No full textPURPOSE:
To compare, on an intra-individual basis, the effect of automated tube voltage selection (ATVS), integrated circuit detector and advanced iterative reconstruction on radiation dose and image quality of aortic CTA studies using 2nd and 3rd generation dual-source CT (DSCT).
MATERIAL AND METHODS:
We retrospectively evaluated 32 patients who had undergone CTA of the entire aorta with both 2nd generation DSCT at 120kV using filtered back projection (FBP) (protocol 1) and 3rd generation DSCT using ATVS, an integrated circuit detector and advanced iterative reconstruction (protocol 2). Contrast-to-noise ratio (CNR) was calculated. Image quality was subjectively evaluated using a five-point scale. Radiation dose parameters were recorded.
RESULTS:
All studies were considered of diagnostic image quality. CNR was significantly higher with protocol 2 (15.0±5.2 vs 11.0±4.2; p<.0001). Subjective image quality analysis revealed no significant differences for evaluation of attenuation (p=0.08501) but image noise was rated significantly lower with protocol 2 (p=0.0005). Mean tube voltage and effective dose were 94.7±14.1kV and 6.7±3.9mSv with protocol 2; 120±0kV and 11.5±5.2mSv with protocol 1 (p<0.0001, respectively).
CONCLUSION:
Aortic CTA performed with 3rd generation DSCT, ATVS, integrated circuit detector, and advanced iterative reconstruction allow a substantial reduction of radiation exposure while improving image quality in comparison to 120kV imaging with FBP
Can dual-energy computed tomography improve visualization of hypoenhancing liver lesions in portal venous phase? Assessment of advanced image-based virtual monoenergetic images
No full textPurpose The purpose was to assess image quality of portal-venous phase dual-energy computed tomography (DECT) for liver lesions. Methods We performed 120-kVp-equivalent linear-blended (LB) and monoenergetic reconstructions from 40 to 190 keV by standard (VMI) and advanced virtual monoenergetic (VMI+) methods. Diagnostic performance, and quantitative and qualitative image analyses were assessed and compared. Results Liver contrast to noise ratio peaked at 40 keV_VMI+, while image quality and reader preference peaked at 50 keV_VMI+. 50 keV_VMI+ scored overall higher diagnostic performance: lesion sensitivity 95.4% vs. 83.3% for both 75 keV_VMI and LB. Conclusions DECT improves assessment of hypoenhancing liver lesions on portal venous phase. 50 keV_VMI+ demonstrated the highest image quality and diagnostic performance over VMI and LB
Automated tube voltage selection for radiation dose and contrast medium reduction at coronary CT angiography using 3rd generation dual-source CT
No full textOBJECTIVES:
To investigate the relationship between automated tube voltage selection (ATVS) and body mass index (BMI) and its effect on image quality and radiation dose of coronary CT angiography (CCTA).
METHODS:
We evaluated 272 patients who underwent CCTA with 3rd generation dual-source CT (DSCT). Prospectively ECG-triggered spiral acquisition was performed with automated tube current selection and advanced iterative reconstruction. Tube voltages were selected by ATVS (70-120 kV). BMI, effective dose (ED), and vascular attenuation in the coronary arteries were recorded. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Five-point scales were used for subjective image quality analysis.
RESULTS:
Image quality was rated good to excellent in 98.9 % of examinations without significant differences for proximal and distal attenuation (all p ≥ .0516), whereas image noise was rated significantly higher at 70 kV compared to ≥100 kV (all p < .0266). However, no significant differences were observed in SNR or CNR at 70-120 kV (all p ≥ .0829). Mean ED at 70-120 kV was 1.5 ± 1.2 mSv, 2.4 ± 1.5 mSv, 3.6 ± 2.7 mSv, 5.9 ± 4.0 mSv, 7.9 ± 4.2 mSv, and 10.7 ± 4.1 mSv, respectively (all p ≤ .0414). Correlation analysis showed a moderate association between tube voltage and BMI (r = .639).
CONCLUSION:
ATVS allows individual tube voltage adaptation for CCTA performed with 3rd generation DSCT, resulting in significantly decreased radiation exposure while maintaining image quality.
KEY POINTS:
• Automated tube voltage selection allows an individual tube voltage adaption in CCTA. • A tube voltage-based reduction of contrast medium volume is feasible. • Image quality was maintained while radiation exposure was significantly decreased. • A moderate association between tube voltage and body mass index was found
Gadolinium-based coronary CT angiography on a clinical photon-counting-detector system: a dynamic circulating phantom study
No full textBackground: Coronary computed tomography angiography (CCTA) offers non-invasive diagnostics of the coronary arteries. Vessel evaluation requires the administration of intravenous contrast. The purpose of this study was to evaluate the utility of gadolinium-based contrast agent (GBCA) as an alternative to iodinated contrast for CCTA on a first-generation clinical dual-source photon-counting-detector (PCD)-CT system.
Methods: A dynamic circulating phantom containing a three-dimensional-printed model of the thoracic aorta and the coronary arteries were used to evaluate injection protocols using gadopentetate dimeglumine at 50%, 100%, 150%, and 200% of the maximum approved clinical dose (0.3 mmol/kg). Virtual monoenergetic image (VMI) reconstructions ranging from 40 keV to 100 keV with 5 keV increments were generated on a PCD-CT. Contrast-to-noise ratio (CNR) was calculated from attenuations measured in the aorta and coronary arteries and noise measured in the background tissue. Attenuation of at least 350 HU was deemed as diagnostic.
Results: The highest coronary attenuation (441 +/- 23 HU, mean +/- standard deviation) and CNR (29.5 +/- 1.5) was achieved at 40 keV and at the highest GBCA dose (200%). There was a systematic decline of attenuation and CNR with higher keV reconstructions and lower GBCA doses. Only reconstructions at 40 and 45 keV at 200% and 40 keV at 150% GBCA dose demonstrated sufficient attenuation above 350 HU.
Conclusion: Current PCD-CT protocols and settings are unsuitable for the use of GBCA for CCTA at clinically approved doses. Future advances to the PCD-CT system including a 4-threshold mode, as well as multi-material decomposition may add new opportunities for k-edge imaging of GBCA.Relevance statementPatients allergic to iodine-based contrast media and the future of multicontrast CT examinations would benefit greatly from alternative contrast media, but the utility of GBCA for coronary photon-counting-dector-CT angiography remains limited without further optimization of protocols and scanner settings.Key PointsGBCA-enhanced coronary PCD-CT angiography is not feasible at clinically approved doses.GBCAs have potential applications for the visualization of larger vessels, such as the aorta, on PCD-CT angiography.Higher GBCA doses and lower keV reconstructions achieved higher attenuation values and CNR
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