Digital chest radiography: an update on modern technology, dose containment and control of image quality

The introduction of digital radiography not only has revolutionized communication between radiologists and clinicians, but also has improved image quality and allowed for further reduction of patient exposure. However, digital radiography also poses risks, such as unnoticed increases in patient dose and suboptimum image processing that may lead to suppression of diagnostic information. Advanced processing techniques, such as temporal subtraction, dual-energy subtraction and computer-aided detection (CAD) will play an increasing role in the future and are all targeted to decrease the influence of distracting anatomic background structures and to ease the detection of focal and subtle lesions. This review summarizes the most recent technical developments with regard to new detector techniques, options for dose reduction and optimized image processing. It explains the meaning of the exposure indicator or the dose reference level as tools for the radiologist to control the dose. It also provides an overview over the multitude of studies conducted in recent years to evaluate the options of these new developments to realize the principle of ALARA. The focus of the review is hereby on adult applications, the relationship between dose and image quality and the differences between the various detector systems

Ferumoxytol-enhanced magnetic resonance imaging methodology and normal values at 1.5 and 3T

Background: Ultrasmall superparamagnetic particles of iron oxide (USPIO)-enhanced magnetic resonance imaging (MRI) can detect tissue-resident macrophage activity and identify cellular inflammation. Clinical studies using this technique are now emerging. We aimed to report a range of normal R2* values at 1.5 and 3 T in the myocardium and other tissues following ferumoxytol administration, outline the methodology used and suggest solutions to commonly encountered analysis problems. Methods: Twenty volunteers were recruited: 10 imaged each at 1.5 T and 3 T. T2* and late gadolinium enhanced (LGE) MRI was conducted at baseline with further T2* imaging conducted approximately 24 h after USPIO infusion (ferumoxytol, 4 mg/kg). Regions of interest were selected in the myocardium and compared to other tissues. Results: Following administration, USPIO was detected by changes in R2* from baseline (1/T2*) at 24 h in myocardium, skeletal muscle, kidney, liver, spleen and blood at 1.5 T, and myocardium, kidney, liver, spleen, blood and bone at 3 T (p < 0.05 for all). Myocardial changes in R2* due to USPIO were 26.5 ± 7.3 s-1 at 1.5 T, and 37.2 ± 9.6 s-1 at 3 T (p < 0.0001 for both). Tissues showing greatest ferumoxytol enhancement were the reticuloendothelial system: the liver, spleen and bone marrow (216.3 ± 32.6 s-1, 336.3 ± 60.3 s-1, 69.9 ± 79.9 s-1; p < 0.0001, p < 0.0001, p = ns respectively at 1.5 T, and 275.6 ± 69.9 s-1, 463.9 ± 136.7 s-1, 417.9 ± 370.3 s-1; p < 0.0001, p < 0.0001, p < 0.01 respectively at 3 T). Conclusion: Ferumoxytol-enhanced MRI is feasible at both 1.5 T and 3 T. Careful data selection and dose administration, along with refinements to echo-time acquisition, post-processing and analysis techniques are essential to ensure reliable and robust quantification of tissue enhancement

Long-term Patient Satisfaction after Percutaneous Treatment of Peripheral Vascular Malformations

Purpose: To determine long-term patient satisfaction for percutaneous treatment by using sclerosing agents (sclerotherapy) and/or arterial embolization for peripherally located vascular malformations (VMs). This treatment has been described as successful; however, there is a relative paucity of published long-term results. Materials and Methods: This retrospective study was institutional review board approved; 107 patients treated for symptomatic VM were evaluated. After informed consent was obtained, 66 patients were sent a questionnaire regarding treatment effectiveness and patient satisfaction. Patient files and imaging data were retrieved to obtain information regarding the VMs and VM treatment. Kaplan-Meier survival curves were constructed to analyze clinical success rates over time. Results: The most frequent reasons for patients to seek treatment were pain (89%, n = 59) and swelling (91%, n = 60). The majority of VMs were the low-flow venous type (83%, n = 55). Three months after treatment, clinical success was reported for 58% (n = 38) of patients and clinical failure was reported for 42% (n = 28). At 1-, 2-, 3-, 4-, and 5-year follow-up, clinical success was 49%, 49%, 42%, 42%, and 42%, respectively. Twenty-seven (40%) patients experienced complications, 12 of which required additional treatment. In all, 35 (53%) patients reported being satisfied with their treatment. Patient satisfaction was closely correlated with clinically successful long-term outcome of treatment. Conclusion: Initial partial or complete relief of VM complaints after percutaneous treatment is expected in 58% of patients, irrespective of VM size or classification. These results were durable over a 5-year follow-up period. (C) RSNA, 200

Ventricular Response to Dobutamine Stress CMR Is a Predictor for Outcome in Fontan Patients

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