Due to its high accuracy, the "all-in-one" MR protocol may become the most important modality after clinical examination and ultrasound in the diagnostic work-up for most patients with suspicion of pancreatic tumors.
For the detection of pancreatic cancer MRI including MRCP is comparable to ERCP and can be regarded as the method of choice in patients with suspected pancreatic cancer. ERCP is the procedure of choice in patients with contraindications to MRI and in patients in whom additional therapeutic procedures are performed.
Even in comparable modern CT scanners there are considerable protocol and scanner-dependent differences in PCTDI/100 mAs. The values for his own scanner should be known to each CT user so that he can develop a dose-optimised, patient and problem-orientated examination strategy.
Imaging procedures suitable for diagnosis of cephalopelvic disproportion, such as radiological pelvimetry, computer- or magnetic resonance imaging (MRI) fail to reflect the dynamics of delivery, including deformations of the birth channel as well as of foetal structures. In order to validate findings of imaging procedures in this respect, a method has been developed to perform dynamic, biomechanical postprocessing of the static information obtained from MRI. Using a specially developed software MRI pixel, matrices of the maternal pelvis and the foetal head were colour-coded and--according to the principle of equal density--line data were created. After sectional attribution of the resulting polygones, a three-dimensional mesh of so called Finite Elements (FE) was created, which can then be used for deformation analysis. The foetal head was then moved through the birth channel by means of computed simulation. This allows not only ongoing deformations to be visualised, but also resulting forces can be calculated at any time of the delivery process for any point of the anatomical model. Furthermore, these calculations can be performed assuming various conditions such as different cephalopelvic dimensions and various labour forces or biomechanical properties of the tissues involved. This paper aims at presenting the method and its mode of working by means of one example of a computed birth simulation.
To compare patient dose and image quality of electron-beam-CT vs. spiral-CT by means of phantom measurements. An EBCT scanner (C-150 XP) and a spiral-CT scanner (GE HiSpeed Advantage) were used to scan three different phantoms. Administered dose, high contrast (HC) resolution, low contrast (LC) lesion detectability and the width of the radiation beams were measured. EBCT showed 25-35% lower HC resolution in comparison to spiral-CT. LC lesion detectability showed equivalent results for S/N vs. patient dose using 3 mm collimation with EBCT and spiral-CT, whereas spiral-CT was superior for 1.5 and 6 mm collimation. Dose measurements revealed a 2 fold higher patient dose using EBCT with 1.5 mm or 6 mm collimation compared to spiral-CT using equivalent scan parameters. No differences were seen using 3 mm collimation. Differences were due to insufficient beamside collimation of the EBCT. The use of EBCT with 6 mm collimation should be avoided, because of impaired performance. Using 3 mm collimation, EBCT showed comparable performance like state of the art spiral-CT despite lower HC resolution.
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