Assessment of task-based image quality for abdominal CT protocols linked with national diagnostic reference levels.

Objectives: To assess task-based image quality for two abdominal protocols on various CT scanners. To establish a relationship between diagnostic reference levels (DRLs) and task-based image quality.

Methods: A protocol for the detection of focal liver lesions was used to scan an anthropomorphic abdominal phantom containing 8- and 5-mm low-contrast (20 HU) spheres at five CTDI levels (4, 8, 12, 16, and 20 mGy) on 12 CTs.

Update of national diagnostic reference levels for adult CT in Switzerland and assessment of radiation dose reduction since 2010.

Objectives: To update the national diagnostic reference levels (DRLs) for adult CT in Switzerland using dose management software and to compare them to the previous Swiss DRLs from 2010.

Methods: CT dose data from 14 radiological institutes with a total of 50 CT scanners were collected with locally installed dose management software between 2014 and 2017. Data were assigned to 15 defined master protocols.

Correction to: National survey on dose data analysis in computed tomography.

The original version of this article, published on 28 May 2018, unfortunately contained a mistake.

National survey on dose data analysis in computed tomography.

Objectives: A nationwide survey was performed assessing current practice of dose data analysis in computed tomography (CT).

Material And Methods: All radiological departments in Switzerland were asked to participate in the on-line survey composed of 19 questions (16 multiple choice, 3 free text). It consisted of four sections: (1) general information on the department, (2) dose data analysis, (3) use of a dose management software (DMS) and (4) radiation protection activities.

Derivation of new diagnostic reference levels for neuro-paediatric computed tomography examinations in Switzerland.

Purpose: Definition of new national diagnostic reference levels (DRLs) for volume computed tomography dose index (CTDI) and dose length product (DLP) for neuro-paediatric CT examinations depending on the medical indication.

Methods: Paediatric cranial CT data sets acquired between January 2013 and December 2016 were retrospectively collected between July 2016 and March 2017 from eight of the largest university and cantonal hospitals that perform most of the neuro-paediatric CTs in Switzerland. A consensus review of CTDI and DLP was undertaken for three defined anatomical regions: brain, facial bone, and petrous bone, each with and without contrast medium application.

Abnormal structure and function of the esophagogastric junction and proximal stomach in gastroesophageal reflux disease.

Objectives: This study applies concurrent magnetic resonance imaging (MRI) and high-resolution manometry (HRM) to test the hypothesis that structural factors involved in reflux protection, in particular, the acute insertion angle of the esophagus into the stomach, are impaired in gastroesophageal reflux disease (GERD) patients.

Methods: A total of 24 healthy volunteers and 24 patients with mild-moderate GERD ingested a test meal. Three-dimensional models of the esophagogastric junction (EGJ) were reconstructed from MRI images.

Exposure of the Swiss population by medical x-rays: 2008 review.

Nationwide surveys on radiation dose to the population from medical radiology are recommended in order to follow the trends in population exposure and ensure radiation protection.The last survey in Switzerland was conducted in 1998,and the annual effective dose from medical radiology was estimated to be 1 mSv y j(-1) per capita. The purpose of this work was to follow the trends in diagnostic radiology between 1998 and 2008 in Switzerland and determine the contribution of different modalities and types of examinations to the collective effective dose from medical x-rays.

An education and training programme for radiological institutes: impact on the reduction of the CT radiation dose.

Objectives: To establish an education and training programme for the reduction of CT radiation doses and to assess this programme's efficacy.

Methods: Ten radiological institutes were counselled. The optimisation programme included a small group workshop and a lecture on radiation dose reduction strategies.

Gastroesophageal junction: structure and function as assessed by using MR imaging.

Purpose: To develop and validate magnetic resonance (MR) imaging protocols for quantitative assessment of the structural and functional properties of the gastroesophageal junction (GEJ) and to compare MR imaging detection of reflux events against concurrent manometry as a reference method.

Materials And Methods: The local ethics committee approved this study, and written informed consent was obtained. Twelve healthy volunteers were examined.

Fast and optimized T1 mapping technique for the noninvasive quantification of gastric secretion.

Purpose: To evaluate the noninvasive quantification of gastric secretion volume after administration of a labeled viscous glucose solution by fast T(1) mapping.

Materials And Methods: T(1) values of a series of labeled and diluted glucose solutions were measured in vitro to characterize the interrelationship between T(1) and contrast agent concentration (C(Gd)) as well as the dependency of relaxivity and reference T(1) (T(10)) on the macromolecular concentration. Abdominal T(1) mapping in five healthy volunteers of different body mass index was performed after filling an intragastric balloon with a labeled and diluted glucose solution.

Optimized and combined T1 and B1 mapping technique for fast and accurate T1 quantification in contrast-enhanced abdominal MRI.

Fast T(1) mapping techniques are a valuable means of quantitatively assessing the distribution and dynamics of intravenously or orally applied paramagnetic contrast agents (CAs) by noninvasive imaging. In this study a fast T(1) mapping technique based on the variable flip angle (VFA) approach was optimized for accurate T(1) quantification in abdominal contrast-enhanced (CE) MRI. Optimization methods were developed to maximize the signal-to-noise ratio (SNR) and ensure effective RF and gradient spoiling, as well as a steady state, for a defined T(1) range of 100-800 ms and a limited acquisition time.

Effects of posture on the physiology of gastric emptying: a magnetic resonance imaging study.

Objective: Gastric contents empty from the stomach despite frequent changes in body position. The mechanism that maintains gastric emptying independent of position is poorly understood. The aim of this study was to determine the effects of body position on gastric emptying and motor function.

Gastric motor function and emptying in the right decubitus and seated body position as assessed by magnetic resonance imaging.

Purpose: To determine the effect of the right decubitus lying body position (RP) on relevant parameters of human gastric motor function in healthy volunteers.

Materials And Methods: Postprandial gastric function after ingestion of a solid/liquid meal (150 g/150 mL) was assessed over 90 minutes in volunteers in the RP and seated position (SP). Ten healthy volunteers were imaged using two MRI systems that differed in architecture and field strength.