Evaluation of thin-slice abdominal DECT using deep-learning image reconstruction in 74 keV virtual monoenergetic images: an image quality comparison.

PURPOSE: To compare noise, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and image quality using deep-learning image reconstruction (DLIR) vs. adaptive statistical iterative reconstruction (ASIR-V) in 0.625 and 2.5 mm slice thickness gray scale 74 keV virtual monoenergetic (VM) abdominal dual-energy CT (DECT). METHODS: This retrospective study was approved by the institutional review board and regional ethics committee. We analysed 30 portal-venous phase abdominal fast kV-switching DECT (80/140kVp) scans. Data were reconstructed to ASIR-V 60% and DLIR-High at 74 keV in 0.625 and 2.5 mm slice thickness. Quantitative HU and noise assessment were measured within liver, aorta, adipose tissue and muscle. Two board-certified radiologists evaluated image noise, sharpness, texture and overall quality based on a five-point Likert scale. RESULTS: DLIR significantly reduced image noise and increased CNR as well as SNR compared to ASIR-V, when slice thickness was maintained (p < 0.001). Slightly higher noise of 5.5-16.2% was measured (p < 0.01) in liver, aorta and muscle tissue at 0.625 mm DLIR compared to 2.5 mm ASIR-V, while noise in adipose tissue was 4.3% lower with 0.625 mm DLIR compared to 2.5 mm ASIR-V (p = 0.08). Qualitative assessments demonstrated significantly improved image quality for DLIR particularly in 0.625 mm images. CONCLUSIONS: DLIR significantly reduced image noise, increased CNR and SNR and improved image quality in 0.625 mm slice images, when compared to ASIR-V. DLIR may facilitate thinner image slice reconstructions for routine contrast-enhanced abdominal DECT.

Quantitative and qualitative assessments of deep learning image reconstruction in low-keV virtual monoenergetic dual-energy CT.

OBJECTIVES: To evaluate a novel deep learning image reconstruction (DLIR) technique for dual-energy CT (DECT) derived virtual monoenergetic (VM) images compared to adaptive statistical iterative reconstruction (ASIR-V) in low kiloelectron volt (keV) images. METHODS: We analyzed 30 venous phase acute abdominal DECT (80/140 kVp) scans. Data were reconstructed to ASIR-V and DLIR-High at four different keV levels (40, 50, 74, and 100) with 1- and 3-mm slice thickness. Quantitative Hounsfield unit (HU) and noise assessment were measured within the liver, aorta, fat, and muscle. Subjective assessment of image noise, sharpness, texture, and overall quality was performed by two board-certified radiologists. RESULTS: DLIR reduced image noise by 19.9-35.5% (p < 0.001) compared to ASIR-V in all reconstructions at identical keV levels. Contrast-to-noise ratio (CNR) increased by 49.2-53.2% (p < 0.001) in DLIR 40-keV images compared to ASIR-V 50 keV, while no significant difference in noise was identified except for 1 and 3 mm in aorta and for 1-mm liver measurements, where ASIR-V 50 keV showed 5.5-6.8% (p < 0.002) lower noise levels. Qualitative assessment demonstrated significant improvement particularly in 1-mm reconstructions (p < 0.001). Lastly, DLIR 40 keV demonstrated comparable or improved image quality ratings when compared to ASIR-V 50 keV (p < 0.001 to 0.22). CONCLUSION: DLIR significantly reduced image noise compared to ASIR-V. Qualitative assessment showed that DLIR significantly improved image quality particularly in thin sliced images. DLIR may facilitate 40 keV as a new standard for routine low-keV VM reconstruction in contrast-enhanced abdominal DECT. KEY POINTS: • DLIR enables 40 keV as the routine low-keV VM reconstruction. • DLIR significantly reduced image noise compared to ASIR-V, across a wide range of keV levels in VM DECT images. • In low-keV VM reconstructions, improvements in image quality using DLIR were most evident and consistent in 1-mm sliced images.

Cardiac systolic dysfunction in past illicit users of anabolic androgenic steroids.

Background: Illicit use of anabolic androgenic steroids (AAS) is associated with left ventricle (LV) systolic dysfunction and increased LV mass (LVM), but whether these findings persist in former AAS users has yet to be elucidated. The objective was to assess LV systolic function, LVM and myocardial fibrosis in current and former illicit AAS users compared with non-users. Methods: Community-based cross-sectional study among men, aged 18­50 years, involved in recreational resistance training. We included 37 current and 33 former illicit AAS users, geometric mean (95%CI), 30 (21; 44) months since AAS cessation, and 30 non-users as controls. We assessed myocardial function and structure using advanced echocardiography and cardiac MRI with late-gadolinium enhancement. Results: Mean (SE) LV global longitudinal strain (GLS) was impaired in former AAS users compared with non-users, −16.7 (0.5) versus −18.2 (0.4) %, P < .05. Mean (SE) LV ejection fraction (EF) was decreased, 51 (1) versus 58 (1) %, P < .001 and LV GLS impaired, −14.5 (0.4)%, P < .001, in current AAS users compared with non-users. Measures of LVM were increased in current AAS users compared with the other two groups, P < .001. Plasma total testosterone was independently associated with reduced LVEF (P = .049) and increased LVM/body surface area (P = .005) in multivariate linear regressions. Focal myocardial fibrosis was not detected in any participants and diffuse myocardial fibrosis, assessed using post-contrast T1-mapping time, did not differ among the three groups. Conclusions: Past illicit AAS use is associated with impaired LV GLS, suggesting subclinical cardiac systolic dysfunction years after AAS cessation.

Increased blood pressure and aortic stiffness among abusers of anabolic androgenic steroids: potential effect of suppressed natriuretic peptides in plasma?

BACKGROUND: Abuse of anabolic androgenic steroids (AAS) is prevalent among recreational athletes and adverse effects on blood pressure (BP) and arterial stiffness could be substantial. Testosterone decreases natriuretic peptides which are key components in BP-regulation and may impair BP-homeostasis in AAS abusers. OBJECTIVE: To investigate BP and aortic stiffness in relation to natriuretic peptides among current AAS abusers, former AAS abusers and controls. METHODS: In this cross-sectional study, 37 current AAS abusers, 33 former AAS abusers and 30 controls were included. All participants were men involved in recreational strength training. We used 24-h BP monitoring, assessed proximal aorta distensibility index (ADI) by MRI and obtained overnight fasting blood samples to measure: midregional proatrial natriuretic peptide (MR-proANP), aldosterone, noradrenaline and copeptin. RESULTS: Current AAS abusers exhibited higher mean (95% confidence interval) 24-h systolic BP than controls [132 (129; 135) versus 124 (120; 128) mmHg, P = 0.005] and systolic hypertension was more frequent among current AAS abusers than controls (51 versus 17%, P = 0.009). ADI was lower among both current and former AAS abusers suggesting higher aortic stiffness; %-difference (95% confidence interval) from controls: -21% (-35; -5) and -21% (-36; -4), P < 0.05. Plasma MR-proANP was decreased, whereas aldosterone and noradrenaline were increased among current AAS abusers compared with former AAS abusers and controls. Decreased MR-proANP was independently associated with increased systolic BP and reduced ADI in multivariate linear regressions. CONCLUSION: Current AAS abusers displayed increased 24-h systolic BP and decreased plasma MR-proANP. Both current and former AAS abusers exhibited higher aortic stiffness.