Deep Learning Denoising of Low-Dose Computed Tomography Chest Images: A Quantitative and Qualitative Image Analysis.

PURPOSE: To assess deep learning denoised (DLD) computed tomography (CT) chest images at various low doses by both quantitative and qualitative perceptual image analysis. METHODS: Simulated noise was inserted into sinogram data from 32 chest CTs acquired at 100 mAs, generating anatomically registered images at 40, 20, 10, and 5 mAs. A DLD model was developed, with 23 scans selected for training, 5 for validation, and 4 for test.Quantitative analysis of perceptual image quality was assessed with Structural SIMilarity Index (SSIM) and Fréchet Inception Distance (FID). Four thoracic radiologists graded overall diagnostic image quality, image artifact, visibility of small structures, and lesion conspicuity. Noise-simulated and denoised image series were evaluated in comparison with one another, and in comparison with standard 100 mAs acquisition at the 4 mAs levels. Statistical tests were conducted at the 2-sided 5% significance level, with multiple comparison correction. RESULTS: At the same mAs levels, SSIM and FID between noise-simulated and reconstructed DLD images indicated that images were closer to a perfect match with increasing mAs (closer to 1 for SSIM, and 0 for FID).In comparing noise-simulated and DLD images to standard-dose 100-mAs images, DLD improved SSIM and FID. Deep learning denoising improved SSIM of 40-, 20-, 10-, and 5-mAs simulations in comparison with standard-dose 100-mAs images, with change in SSIM from 0.91 to 0.94, 0.87 to 0.93, 0.67 to 0.87, and 0.54 to 0.84, respectively. Deep learning denoising improved FID of 40-, 20-, 10-, and 5-mAs simulations in comparison with standard-dose 100-mAs images, with change in FID from 20 to 13, 46 to 21, 104 to 41, and 148 to 69, respectively.Qualitative image analysis showed no significant difference in lesion conspicuity between DLD images at any mAs in comparison with 100-mAs images. Deep learning denoising images at 10 and 5 mAs were rated lower for overall diagnostic image quality ( P < 0.001), and at 5 mAs lower for overall image artifact and visibility of small structures ( P = 0.002), in comparison with 100 mAs. CONCLUSIONS: Deep learning denoising resulted in quantitative improvements in image quality. Qualitative assessment demonstrated DLD images at or less than 10 mAs to be rated inferior to standard-dose images.

In-situ formation of Ag nanoparticles in the MAO coating during the processing of cp-Ti.

Silver nanoparticle (Ag-NP) containing antibacterial micro-arc oxidation (MAO) coatings have already been synthesized over titanium-based materials via the MAO process employed in silver acetate (AgC2H3O2) containing electrolyte. However, the way of incorporation and in-situ formation of Ag-NPs within the MAO coating have not been documented yet. Present work was initiated to reveal the mechanism of Ag-NP formation within the MAO coatings. Thus, the structure of the MAO coating fabricated on commercial purity titanium in the AgC2H3O2-containing electrolyte was investigated by electron microscopy techniques. To this end, the cross-sectional high-resolution electron microscopy studies were carried out on lamella cut out with the focused ion beam technique, and these investigations were backed by X-ray photoelectron spectroscopy measurements of chemical composition on the surface of the MAO coating. These studies revealed that Ag is dispersed in the form of nanoparticles throughout the coating and that a higher density was confirmed closer to the micro-pores.

Improved efficiency of CT interpretation using an automated lung nodule matching program.

OBJECTIVE: The purpose of this study was to assess the impact of an automated program on improvement in lung nodule matching efficiency. MATERIALS AND METHODS: Four thoracic radiologists independently reviewed two serial chest CT examinations from each of 57 patients. Each radiologist performed timed manual lung nodule matching. After 6 weeks, all radiologists independently repeated the timed matching portion using an automated nodule matching program. The time required for manual and automated matching was compared. The impact of nodule size and number on matching efficiency was determined. RESULTS: An average of 325 (range, 244-413) noncalcified solid pulmonary nodules was identified. Nodule matching was significantly faster with the automated program irrespective of the interpreting radiologist (p < 0.0001 for each). The maximal time saved with automated matching was 11.4 minutes (mean, 2.3 ± 2.0 minutes). Matching was faster in 56 of 57 cases (98.2%) for three readers and in 46 of 57 cases (80.7%) for one reader. There were no differences among readers with respect to the mean time saved per matched nodule (p > 0.5). The automated program achieved 90%, 90%, 79%, and 92% accuracy for the four readers. The improvement in efficiency for a given patient using the automated technique was proportional to the number of matched nodules (p < 0.0001) and inversely proportional to nodule size (p < 0.05). CONCLUSION: Use of the automated lung nodule matching program significantly improves diagnostic efficiency. The time saved is proportionate to the number of nodules identified and inversely proportional to nodule size. Adoption of such a program should expedite CT examination interpretation and improve report turnaround time.

[Adrenal angioma simulating pheochromocytoma]. / Angioma surrenalico simulante un feocromocitoma.

The authors report a case of adrenal angioma (a rare benign mesenchymal tumour) which was diagnosed by chance ("incidentaloma") and whose clinical and instrumental characterisation led to the hypothesis of a pheochromocytoma. The various diagnostic methods used are analysed together with results and the possible causes of their erroneous interpretation.

[Hydatid cyst of the kidney. Case report]. / Cisti idatidea del rene. Descrizione di un caso.

The authors present a case of echinococcosis of the kidney that is interesting because of the uncommon site of localization; they illustrate their diagnostic and therapeutic approach to surgical and pharmacological management of the infection. Epidemiologically, hydatid cysts localized in the kidney occur far less often in northern Italy compared with the central-southern areas and the islands. However, echinococcosis should be suspected whenever symptoms include lumbar pain or swelling. Echography will reveal characteristic capsule and daughter cysts, while radiographic studies will often show a rim of calcification on the outline of the kidney. This information should be considered in conjunction with serologic tests (IgG-specific titers). If results to these tests are negative, abdominal computed tomography scans with contrast medium may be useful in demonstrating more details to establish diagnosis. Conservative (pericystectomy) or radical (nephrectomy) surgery is usually effective in curing the patient. Pharmacological therapy with albendazole can be a useful support in association with surgery or as an alternative single therapy in patients with other medical problems or spontaneous fistula formation that preclude surgery.

[Hypotension following maximum physical exercise. Evaluation of hemodynamic and humoral mechanisms]. / Ipotensione dopo esercizio fisico massimale. Valutazione dei meccanismi emodinamici ed umorali.

The period after exercise has received little attention although there are rapid and arge changes in the loading conditions of the heart and circulation which may precipitate hypotension or arrhythmias. Little is known of the time course of the recovery of cardiac output and humoral changes occurring during this periods. After a single bout of prolonged muscular exercise, systolic and diastolic blood pressure decrease, sometimes for several hours. In a recent controlled study for the possible effects of the expecting of the exercise, a reduction in diastolic blood pressure was observed particularly in the first 10 min and lasting to 60 min. The mechanisms of the acute hypotensive effect of upright dynamic exercise have not yet been clarified. Little is known of the time course of the recovery of cardiac output, humoral and autonomic changes occurring during this period. Conflicting data are presented by different authors. The aim of the present study was to study the role of the haemodynamic and humoral changes in the modifications in blood pressure occurring in the hour of recovery after maximal exercise in normal subjects. Nine normal male volunteers (age: 28:34 years) have been studied on 2 separate days. Subjects were studied on a non-exercise (control) day (the subjects maintained the upright position for 30 min, followed by 60 min supine) and an exercise day (maximal upright bicycle exercise followed by supine rest for 60 min), in a random order. The following data have been recorded before the test and serially during 60 minute supine: systolic and diastolic blood pressure, heart rate, haemodynamic changes (by suprasternal aortic Doppler), and humoral changes (renin).(ABSTRACT TRUNCATED AT 250 WORDS)

Streptococcus pneumonia YlxR at 1.35 A shows a putative new fold.

The structure of the YlxR protein of unknown function from Streptococcus pneumonia was determined to 1.35 A. YlxR is expressed from the nusA/infB operon in bacteria and belongs to a small protein family (COG2740) that shares a conserved sequence motif GRGA(Y/W). The family shows no significant amino-acid sequence similarity with other proteins. Three-wavelength diffraction MAD data were collected to 1.7 A from orthorhombic crystals using synchrotron radiation and the structure was determined using a semi-automated approach. The YlxR structure resembles a two-layer alpha/beta sandwich with the overall shape of a cylinder and shows no structural homology to proteins of known structure. Structural analysis revealed that the YlxR structure represents a new protein fold that belongs to the alpha-beta plait superfamily. The distribution of the electrostatic surface potential shows a large positively charged patch on one side of the protein, a feature often found in nucleic acid-binding proteins. Three sulfate ions bind to this positively charged surface. Analysis of potential binding sites uncovered several substantial clefts, with the largest spanning 3/4 of the protein. A similar distribution of binding sites and a large sharply bent cleft are observed in RNA-binding proteins that are unrelated in sequence and structure. It is proposed that YlxR is an RNA-binding protein.