[en] The clinical records and procedural details of 28 angioplasty procedures performed on 25 patients were reviewed. Long-term follow-up was conducted by examining the referring physicians' records and by direct telephone contact with the patient. Nine patients had neurologic symptoms only, eight patients had arm claudication symptoms only, seven patients had both neurologic and arm symptoms, and two patients underwent dilation procedures to provide graft inflow. Procedural complications were a stroke in the contralateral carotid distribution during follow-up thoracic aortography, and an embolus to the fifth digit (of no clinical significance). Long-term success of the angioplasty procedure did not correlate with initial symptoms, degree of stenosis, lesion length, or postangioplasty appearance. All patients with arm and neurologic symptoms and who were followed up for 3 years, with the exception of the patient who suffered a periprocedural stroke

[en] Esophageal perforation with subsequent formation of a mediastinal abscess is a well-recognized clinical entity. Causes include perforation following rigid and fiberoptic endoscopy, bouginage, breakdown of surgical anastomoses, and protracted vomiting. No matter what the cause, this disorder is associated with a high morbidity and, in patients in whom no intervention occurs, a definite mortality. In the past, surgery has been the treatment of choice. Although percutaneous drainage techniques have been utilized in some cases, they are frequently less attractive due to the location of the esophagus and its proximity to thoracic organs and vascular structures. The authors drained a total of eight esophageal perforations through a transesophageal route with minimal patient morbidity. The authors report these cases with discussion of the techniques and patient follow-up

[en] A retrospective review of 19 patients with a diagnosis of pyogenic spine infection evaluated with spine CT was performed. In addition to displaying bone involvement, CT routinely depicted paraspinous and epidural involvement often not apparent on conventional radiographs or nuclear medicine studies. CT proved particularly useful in (1) workup of patients with clinical evidence of infection associated with back pain and neurologic symptoms, (2) evaluation of patients with fever and recurrent back pain following recent spine surgery, (3) guiding diagnostic aspiration of suspected spinal regions for culture and sensitivity, (4) pre-operative planning of debridement surgery. (orig.)

[en] This paper compares the diagnostic performance of CT arterial portography (CTAP) and high-field MR imaging at 1.5-T in the preoperative detection and localization of metastases. Thirty-one patients with colon cancer were imaged using CTAP and 1.5-T MR imaging. A blinded, retrospective review of the images were performed, with analysis of individual lesions and evaluation of reader confidence for predicting segmental involvement by metastases and potential for surgical resection. The presence or absence of lesions was based on intraoperative and pathologic findings. Preliminary results show a sensitivity of 85% for CTAP and 74% for MR imaging. Malignant involvement in the right lobe was predicted by CTAP in 95% of cases and in 90% of cases by MR imaging. Involvement in the left lobe was predicted by CTAP in 82% of cases and by MR imaging in 63% of cases

[en] Current drive using RF waves has been proposed as a means to reduce the tearing fluctuations responsible for anomalous energy transport in the RFP. A traveling wave antenna operating at 800 MHz is being used to launch lower hybrid waves into MST to assess the feasibility of this approach. Parameter studies show that edge density is a major factor in antenna/plasma coupling. Gas puffing near the antenna is shown to alter coupling without changing plasma conditions. Hard x-ray emission has been correlated to RF power and is seen to vary strongly with direction of power flow through the antenna

[en] Full text: Current profile control is a crucial tool for understanding the drive of tearing fluctuations in the reversed field pinch. Simulations of auxiliary edge parallel current drive predict a reduction of tearing activity, and indeed in experiment there is a significant decrease of magnetic fluctuations with inductive edge current drive in the MST. This in turn leads to a dramatically increased (factor of 10) electron energy confinement time and evidence that transport is no longer dominated by magnetic turbulence. The use of rf waves to drive edge current offers steady and more precise profile control than the existing inductive approach, which is transient, radially diffuse and induces a large change to the magnetic equilibrium. Lower Hybrid (LH) and electron Bernstein waves (EBW) are being studied as candidates for the overdense, high beta plasma. Ray tracing and Fokker-Planck calculations predict good absorption and directional control for both waves, as required for effective current drive. The lower hybrid studies involve novel antenna design and extending LH physics to plasmas with high dielectric constant. In contrast, the EBW studies benefit from simpler antenna requirements, but the mode conversion wave physics needs to be established for a high beta RFP plasma. At present, localized x-ray emission has been observed with rf injection at the 100 kW level of each wave. Toroidally localized hard x-ray (HXR) emission with energy as high as 50 keV is observed during LH injection (with ∼ 125 kW coupled to the plasma). The flux and energy spectrum is consistent with acceleration of plasma electrons in the antenna near field with electric fields computed by electromagnetic modeling. Enhanced SXR emission (4 - 7 keV) is observed during EBW injection (∼ 100 kW of 3.6 GHz launched) when accompanied by a period of low magnetic fluctuations. Hardware for the EBW current drive project is being upgraded to use a 1 MW, 5.5 GHz klystron, with the higher frequency (shorter wavelength) enabling the use of a smaller port hole for the launching antenna. Work supported by U.S. Department of Energy. (author)

[en] The atlas goes beyond conventional diagnostic radiology, exploring and explaining the potentials of interventional radiology as the next step following the stage where taking and interpreting radiographs have reached a high grade of maturity, indicating new applications. The authors have collected for this book many characteristic X-rays and combined them with schematic drawings of the anatomy and with technical details of the case under review. The reader will also find a wealth of practical advice and tips and information about the suitability and achievements of the various techniques such as, e.g., atherectomy, embolisation, PTCA, organ biopsy, percutaneous nephrostomy, gastrostomy, percutaneous transhepatic chloangiography. (orig.)

[en] Full text: There are two cases in MST where a central helical magnetic structure emerges and produces a region of improved confinement. One case is due to a single tearing mode dominating the core-resonant m = 1 mode spectrum. Here, runaway electrons are observed with energies > 100 keV, a feature normally absent in standard, stochastic RFP plasmas. These electrons are deduced to be confined in a locally non-stochastic region inside the dominant mode's magnetic island. The other case corresponds to an additional mode that emerges following global reconnection events. In this case, the m = 1 spectrum is fairly flat, but the electron temperature profile exhibits a local peaking corresponding to a substantially reduced electron thermal diffusivity. While neither of these cases corresponds to a substantial improvement in global confinement, recent discharges near MST's maximum toroidal plasma current exhibit very peaked tearing mode spectra. These spectra bear a striking similarity to those in the RFX-mod RFP which produce a several-fold improvement in global confinement. Helical structures in the RFP are of interest not only for their contribution to confinement improvement, but also for their connection to 3D physics in other configurations. Work supported by U.S. Dept. of Energy and National Science Foundation. (author)

[en] We have increased substantially the electron and ion temperatures, the electron density, and the total beta in plasmas with improved energy confinement in the Madison Symmetric Torus (MST). The improved confinement is achieved with a well-established current profile control technique for reduction of magnetic tearing and reconnection. A sustained ion temperature >1 keV is achieved with intensified reconnection-based ion heating followed immediately by current profile control. In the same plasmas, the electron temperature reaches 2 keV, and the electron thermal diffusivity drops to about 2 m² s^-1. The global energy confinement time is 12 ms. This and the reported temperatures are the largest values yet achieved in the reversed-field pinch (RFP). These results were attained at a density ∼10¹⁹ m^-3. By combining pellet injection with current profile control, the density has been quadrupled, and total beta has nearly doubled to a record value of about 26%. The Mercier criterion is exceeded in the plasma core, and both pressure-driven interchange and pressure-driven tearing modes are calculated to be linearly unstable, yet energy confinement is still improved. Transient momentum injection with biased probes reveals that global momentum transport is reduced with current profile control. Magnetic reconnection events drive rapid momentum transport related to large Maxwell and Reynolds stresses. Ion heating during reconnection events occurs globally, locally, or not at all, depending on which tearing modes are involved in the reconnection. To potentially augment inductive current profile control, we are conducting initial tests of current drive with lower-hybrid and electron-Bernstein waves.

[en] The results of a beam test performed at the KEK PS in June 2005 are presented. Drift properties of an argon-isobutane mixture have been accurately measured and compared with predictions at magnetic fields between 0 and 1 T. The r.m.s. point resolution of a padrow is compared with simulation and with an analytical calculation. The fundamental limitations due to detector geometry and gas properties are reviewed and the measured performances of the detector are found to be close to this limit. A numerical application to the case of a linear collider Time Projection Chamber (TPC) is presented.