Δευτέρα 13 Ιουνίου 2022

Fat Quantification in Dual-Layer Detector Spectral Computed Tomography: Experimental Development and First In-Patient Validation

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imageObjectives Fat quantification by dual-energy computed tomography (DECT) provides contrast-independent objective results, for example, on hepatic steatosis or muscle quality as parameters of prognostic relevance. To date, fat quantification has only been developed and used for source-based DECT techniques as fast kVp-switching CT or dual-source CT, which require a prospective selection of the dual-energy imaging mode. It was the purpose of this study to develop a material decomposition algorithm for fat quantification in phantoms and validate it in vivo for patient liver and skeletal muscle using a dual-layer detector-based spectral CT (dlsCT), which automatically generates spectral information with every scan. Materials and Methods For this feasibility study, phantoms were created with 0%, 5%, 10%, 25%, and 40% fat and 0, 4.9, and 7.0 mg/mL iodine, respectively. Phantom scans were performed with the IQon spectral CT (Philips, the Netherlands) at 120 kV and 140 kV and 3 T magnetic resonance (MR) (Philips, the Netherlands) chemical-shift relaxometry (MRR) and MR spectroscopy (MRS). Based on maps of the photoelectric effect and Compton scattering, 3-material decomposition was done for fat, iodine, and phantom material in the image space. After written consent, 10 patients (mean age, 55 ± 18 years; 6 men) in need of a CT staging were prospectively included. All patients received contrast-enhanced abdominal dlsCT scans at 120 kV and MR imaging scans for MRR. As reference tissue for the liver and the skeletal muscle, retrospectively available non–contrast-enhanced spectral CT data sets were used. Agreement between dlsCT and MR was evaluated for the phantoms, 3 hepatic and 2 muscular regions of interest per patient by intraclass correlation coefficients (ICCs) and Bland-Altman analyses. Results The ICC was excellent in the phantoms for both 120 kV and 140 kV (dlsCT vs MRR 0.98 [95% confidence interval (CI), 0.94–0.99]; dlsCT vs MRS 0.96 [95% CI, 0.87–0.99]) and in the skeletal muscle (0.96 [95% CI, 0.89–0.98]). For log-transformed liver fat values, the ICC was moderate (0.75 [95% CI, 0.48–0.88]). Bland-Altman analysis yielded a mean difference of −0.7% (95% CI, −4.5 to 3.1) for the liver and of 0.5% (95% CI, −4.3 to 5.3) for the skeletal muscle. Interobserver and intraobserver agreement were excellent (>0.9). Conclusions Fat quantification was developed for dlsCT and agreement with MR techniques demonstrated for patient liver and muscle. Hepatic steatosis and myosteatosis can be detected in dlsCT scans from clinical routine, which retrospectively provide spectral information independent of the imaging mode.
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Homoarginine Treatment of Rats Improves Cardiac Function and Remodeling in Response to Pressure Overload

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Abstract

Background

Low serum concentrations of the amino acid homoarginine (HA) are associated with increased cardiovascular mortality by incompletely understood mechanisms.

Objectives

This study sought to assess the influence of HA on cardiac remodeling in rats undergoing either transaortic banding or inhibition of nitric oxide synthesis by Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME).

Methods

Male Wistar rats (n=136) underwent a sham operation (SH) or aortic banding (AB). Both groups were equally divided into fourteen subgroups, receiving different doses of HA alone or in combination with lisinopril, spironolactone, or L-NAME over 4 weeks.

Results

HA treatment in AB animals resulted in a dose-dependent improvement of cardiac function up to a concentration of 800 mg·kg-1·day-1. Combining 800 mg·kg-1·day-1 HA with spironolactone or lisinopril yielded additional effects, showing a positive correlation with LV ejection fraction (+33%, p=0.0002) and fractional shortening (+41%, p=0.0014). An inverse association was observed with collagen area fraction (-41%, p<0.0001), myocyte cross-sectional area (-22%, p<0.0001) and the molecular markers atrial natriuretic factor (-74%, p=0.0091), brain natriuretic peptide (-42%, p=0.0298), beta-myosin heavy chain (-46%, p=0.0411), and collagen type V alpha 1 chain (-73%, p=0.0257) compared to placebo-treated AB animals. Co-administration of HA and L-NAME was found to attenuate cardiac remodeling and prevent NO-deficient hypertension following AB.

Conclusion

HA treatment has led to a dose-dependent improvement of myocardial function and marked histological and molecular changes in cardiac remodeling following AB. Combining HA with standard heart failure medication resulted in additional beneficial effects boosting its direct impact on heart failure pathophysiology.

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Total thyroidectomy versus hemithyroidectomy with intraoperative radiofrequency ablation for unilateral thyroid cancer with contralateral nodules: A propensity score matching study

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For unilateral papillary thyroid carcinoma (PTC) patients with contralateral benign nodules, optimal treatment decisions are made according to patient preference and the disease's pathological features. This s...
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Isolated cerebral toxoplasmosis 17 years post renal transplant

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A novel nonsense PKD1L1 variant cause heterotaxy syndrome with congenital asplenia in a Han Chinese patient

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Journal of Human Genetics, Published online: 13 June 2022; doi:10.1038/s10038-022-01053-w

A novel nonsense PKD1L1 variant cause heterotaxy syndrome with congenital asplenia in a Han Chinese patient
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Genetics of amyotrophic lateral sclerosis: seeking therapeutic targets in the era of gene therapy

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Journal of Human Genetics, Published online: 13 June 2022; doi:10.1038/s10038-022-01055-8

Genetics of amyotrophic lateral sclerosis: seeking therapeutic targets in the era of gene therapy
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