Characterization of magnetic interference and image artefacts during simultaneous in-beam MR imaging and proton pencil beam scanning.

For the first time, a low-field open magnetic resonance (MR) scanner was combined with a proton pencil beam scanning (PBS) research beamline. The aim of this study was to characterize the magnetic fringe fields produced by the PBS system and measure their effects on MR image quality during simultaneous PBS irradiation and image acquisition. A magnetic field camera measured the change in central resonance frequency (Δf ) and magnetic field homogeneity (ΔMFH) of the B field of the MR scanner during operation of the beam transport and scanning magnets.

Magnetic Resonance Imaging for Quantitative Assessment of Lung Aeration: A Pilot Translational Study.

Computed tomography is the gold standard for lung aeration assessment, but exposure to ionizing radiation limits its application. We assessed the ability of magnetic resonance imaging (MRI) to detect changes in lung aeration in isolated swine lung and the potential of translation of the findings to human MRI scans. We performed MRI scans in 11 isolated non-injured and injured swine lungs, as well as 6 patients both pre- and post-operatively.

Clinical Implementation of Dual-energy CT for Proton Treatment Planning on Pseudo-monoenergetic CT scans.

Purpose: To determine whether a standardized clinical application of dual-energy computed tomography (DECT) for proton treatment planning based on pseudomonoenergetic CT scans (MonoCTs) is feasible and increases the precision of proton therapy in comparison with single-energy CT (SECT).

Methods And Materials: To define an optimized DECT protocol, CT scan settings were analyzed experimentally concerning beam hardening, image quality, and influence on the heuristic conversion of CT numbers into stopping-power ratios (SPRs) and were compared with SECT scans with identical CT dose. Differences in range prediction and dose distribution between SECT and MonoCT were quantified for phantoms and a patient.

A ³¹P-magnet resonance spectroscopy study on the metabolism of human masseter in individuals with different vertical facial pattern.

Objective: The objective of this study was to investigate differences in masseter metabolism by (31)P-Chemical Shift Imaging (CSI) in adult individuals with different vertical facial patterns. The clinical study should be supported by functional findings at the mRNA level after orthognathic surgery.

Study Design: Twenty-two male volunteers (mean age 24.

Quantitative modifications of TNM staging, clinical staging and therapeutic intent by FDG-PET/CT in patients with non small cell lung cancer scheduled for radiotherapy--a retrospective study.

It is obvious that FDG-PET has added value to CT, but there is still insufficient data to define the role of FDG-PET/CT in clinical practice. Usually data are gathered from multiple sources and in consequence the information obtained is heterogeneous and not always comparable between patients. To alleviate this lack of data, we attempted to investigate the differences in staging and therapeutic intent as compared with conventional staging in non small cell lung cancer (NSCLC) patients scheduled for RT after adding FDG-PET/CT to conventional staging in 104 included subjects.

Bone density of the midpalatal suture 7 months after surgically assisted rapid palatal expansion in adults.

Introduction: The aims of this study were to analyze changes in bone density of the midpalatal suture after surgically assisted rapid palatal expansion (SARPE) with the bone-borne Dresden Distractor (DD; ITU, Dresden, Germany) via computed tomography (CT) and to compare of preoperative surgical findings with a control group.

Methods: Sixteen adult patients (mean age 24.5 years) underwent axial CT scans before and 7 months after SARPE.

Changes in nasal volume after surgically assisted bone-borne rapid maxillary expansion.

Introduction: The purposes of this study were to detect, locate, and examine the changes in transverse nasal width, area, and volume from bone-borne, surgically assisted rapid maxillary expansion (SARME) with the Dresden distractor by using computer tomography (CT).

Methods: Sixteen patients (average age, 28.7 years) underwent axial CT scanning before and 6 months after SARME.

Comment on "Developing DCE-CT to quantify intra-tumor heterogeneity in breast tumors with differing angiogenic phenotype".

In our comment some essential issues concerning determination of arterial input function (AIF), cardiac and respiratory related motion artifacts, contrast agent application and compartmental model fitting done by Cao et al., 2009 are discussed.

Regional lung aeration and ventilation during pressure support and biphasic positive airway pressure ventilation in experimental lung injury.

Introduction: There is an increasing interest in biphasic positive airway pressure with spontaneous breathing (BIPAP+SBmean), which is a combination of time-cycled controlled breaths at two levels of continuous positive airway pressure (BIPAP+SBcontrolled) and non-assisted spontaneous breathing (BIPAP+SBspont), in the early phase of acute lung injury (ALI). However, pressure support ventilation (PSV) remains the most commonly used mode of assisted ventilation. To date, the effects of BIPAP+SBmean and PSV on regional lung aeration and ventilation during ALI are only poorly defined.

CT analysis of nasal volume changes after surgically-assisted rapid maxillary expansion.

Objective: Aim of this study was to detect the changes in nasal volume due to bone-borne, surgically-assisted rapid palatal expansion (RPE) with the Dresden Distractor using computed tomography (CT).

Materials And Methods: 17 patients (mean age 28.8) underwent axial CT scanning before and 6 months after RPE.

Dose reduction in computed tomography: the effect of eye and testicle shielding on radiation dose measured in patients with beryllium oxide-based optically stimulated luminescence dosimetry.

The aim of this study was to assess the effect of eye and testicle shielding on radiation dose to the lens and the testes of patients undergoing CT examinations. Fifty-one male patients underwent CT twice with identical protocols initially without, the second time with protective garments. Doses to the testes and the lenses were recorded with beryllium oxide-based dosimeters.

Finite element representation of bone substitute remodelling in the jaw bone.

The finite element (FE) method was originally developed on a physical basis for the computation of structure-mechanical problems. Meanwhile, it has been widely applied to medical issues. This study sought a suitable method to build a FE model for remodelling processes in osseous defects supplemented with bone substitute material.

Three-dimensional evaluation of surgically assisted implant bone-borne rapid maxillary expansion: a pilot study.

Introduction: The purpose of this study was to evaluate 3-dimensional changes in dental, alveolar, and skeletal structures caused by a bone-borne implant-supported rapid maxillary expansion device (Dresden distractor).

Methods: Axial computed tomography scans of 10 patients (mean age, 25.3 years) treated with the Dresden distractor were examined.

Skeletally-anchored rapid maxillary expansion using the Dresden Distractor.

Introduction: It was the aim of this study to carry out a 3-D analysis of the teeth, alveolar and skeletal structures during bone-borne, surgically-assisted rapid maxillary expansion (RME) with the Dresden Distractor (DD). We aimed to determine whether a translatory and skeletal movement of the segments would be possible while reducing the dento-alveolar side effects associated with tooth-borne RME.

Materials And Methods: Standardized axial computed tomography (CT) was performed on twelve patients averaging 25.

External compression increases forearm perfusion.

Application of compression stockings to the lower extremities is a widely used therapeutic intervention to improve venous return, but there is little information about the effects of compression on local arterial perfusion. Therefore, we tested the hypothesis that a positive external pressure increases forearm perfusion. The relation of increasing external pressure induced by standardized compression to the arterial inflow and arterial flow reserve of the forearm was critically evaluated in a group of healthy young men (n = 9).

MR perfusion measurements on pharyngeal tumors: comparison of quantification strategies.

For the case of pharyngeal carcinomas, the clinical value as well as the stability of several evaluation methods of MR tomographic perfusion measurement are compared. Eighteen patients suffering from histologically proven squamous cell carcinomas were investigated by MR tomography (1.5 T, 0.

MRI of the coronary arteries: flip angle train optimization for 3D sequences.

Application of contrast agents in MRI of coronary arteries improves contrast-to-noise ratio (CNR), but widens the range of T1 relaxation times of the tissues to be imaged. The flip angle train, generated for the measurement of all phase-encoding steps in the 3rd spatial dimension of the navigator echo FLASH sequence used, is optimal only for one T1. Computer simulations show that it is not advisable to optimize the sequence on the basis of an extremely short T1 relaxation time (such as in the case of contrast-enhanced vessels) because the imaging of the surrounding tissue would be negatively influenced.

Gadomer-17-enhanced 3D navigator-echo MR angiography of the pulmonary arteries in pigs.

The goal of this study was visualisation and quality assessment of the pulmonary arteries in pigs with modified navigator-echo magnetic resonance angiography using an intravascular contrast agent. Five sedated pigs were examined in a clinical 1.5-T system with modified three-dimensional navigator-echo magnetic resonance angiography (slice thickness 3 mm, pixel size 2.

MR evaluation in patients with isolated anosmia since birth or early childhood.

Background And Purpose: Anosmias with chromosomal disorders has been well investigated. However, isolated anosmia (IA) has received less attention, although it occurs more frequently. We compared frontobasal structures in patients with IA since birth or early childhood with those in control subjects.