Focal Spot, Spring 2004

https://digitalcommons.wustl.edu/focal_spot_archives/1096/thumbnail.jp

State of the art: iterative CT reconstruction techniques

Owing to recent advances in computing power, iterative reconstruction (IR) algorithms have become a clinically viable option in computed tomographic (CT) imaging. Substantial evidence is accumulating about the advantages of IR algorithms over established analytical methods, such as filtered back projection. IR improves image quality through cyclic image processing. Although all available solutions share the common mechanism of artifact reduction and/or potential for radiation dose savings, chiefly due to image noise suppression, the magnitude of these effects depends on the specific IR algorithm. In the first section of this contribution, the technical bases of IR are briefly reviewed and the currently available algorithms released by the major CT manufacturers are described. In the second part, the current status of their clinical implementation is surveyed. Regardless of the applied IR algorithm, the available evidence attests to the substantial potential of IR algorithms for overcoming traditional limitations in CT imaging

Focal Spot, Winter 2008/2009

https://digitalcommons.wustl.edu/focal_spot_archives/1110/thumbnail.jp

Focal Spot, Fall/Winter 1996

https://digitalcommons.wustl.edu/focal_spot_archives/1071/thumbnail.jp

Focal Spot, Fall/Winter 2010/2011

https://digitalcommons.wustl.edu/focal_spot_archives/1115/thumbnail.jp

When alarm bells ring: emergency tinnitus

OBJECTIVE: The aim of this study is to develop a diagnostic-therapeutic algorithm for those suffering from tinnitus who seek emergency aid. MATERIALS AND METHODS: A literature review has been performed on articles from the last 30 years. RESULTS: It is important to activate medical or surgical diagnostic and therapeutic strategies, in order to safeguard and rehabilitate the various functions affected. Psychiatric comorbidity is the most frequent pathological condition of those with serious or catastrophic tinnitus. In these cases, mortality risk is linked to suicide, morbidity to tinnitus-correlated distress. CONCLUSIONS: Tinnitus, mainly linked to loss of hearing, is a frequent symptom among the population at large. About 7% of those affected by tinnitus turn to their doctor to solve their problem, while between 0.5 and 2% request urgent medical assistance. Their cry for help may be the result of an acute onset of tinnitus or the rapid impairment of an already chronic condition. Tinnitus is not considered an urgent ear, nose and throat (ENT) condition by the Associazione Otorinolaringologi Ospedalieri Italiani (AOOI) [Italian Association of Hospital ENT], even though there are many pathological conditions, sometimes serious, associated with tinnitus and emergency action is necessary to reduce the risk of morbidity and mortality

Dual Source Photon-Counting Computed Tomography-Part II: Clinical Overview of Neurovascular Applications

Photon-counting detector (PCD) is a novel computed tomography detector technology (photon-counting computed tomography-PCCT) that presents many advantages in the neurovascular field, such as increased spatial resolution, reduced radiation exposure, and optimization of the use of contrast agents and material decomposition. In this overview of the existing literature on PCCT, we describe the physical principles, the advantages and the disadvantages of conventional energy integrating detectors and PCDs, and finally, we discuss the applications of the PCD, focusing specifically on its implementation in the neurovascular field

PET-MR imaging using a tri-modality PET/CT-MR system with a dedicated shuttle in clinical routine

Tri-modality PET/CT-MRI includes the transfer of the patient on a dedicated shuttle from one system into the other. Advantages of this system include a true CT-based attenuation correction, reliable PET-quantification and higher flexibility in patient throughput on both systems. Comparative studies of PET/MRI versus PET/CT are readily accomplished without repeated PET with a different PET scanner at a different time point. Additionally, there is a higher imaging flexibility based on the availability of three imaging modalities, which can be combined for the characterization of the disease. The downside is a somewhat higher radiation dose of up to 3mSv with a low dose CT based on the CT-component, longer acquisition times and potential misalignment between the imaging components. Overall, the tri-modality PET/CT-MR system offers comparative studies using the three different imaging modalities in the same patient virtually at the same time, and may help to develop reliable attenuation algorithms at the same tim

Advanced Neuroimaging with Computed Tomography Scanning

International audienceThe x-ray computed tomography (CT) is well known as a useful imaging method and thus CT images have continuingly been used for many applications, especially in medical fields. This book discloses recent advances and new ideas in theories and applications for CT imaging and its analysis. The 16 chapters selected in this book cover not only the major topics of CT imaging and analysis in medical fields, but also some advanced applications for forensic and industrial purposes. These chapters propose state-of-the-art approaches and cutting-edge research results