Magnetic Resonance Imaging (MRI) is among the most important medical imaging techniques available today. There is an installed base of approximately 15,000 MRI scanners worldwide. Each of these ...scanners is capable of running many different "pulse sequences", which are governed by physics and engineering principles, and implemented by software programs that control the MRI hardware. To utilize an MRI scanner to the fullest extent, a conceptual understanding of its pulse sequences is crucial. This book offers a complete guide that can help the scientists, engineers, clinicians, and technologists in the field of MRI understand and better employ their scanner.
·Explains pulse sequences, their components, and the associated image reconstruction methods commonly used in MRI·Provides self-contained sections for individual techniques·Can be used as a quick reference guide or as a resource for deeper study·Includes both non-mathematical and mathematical descriptions ·Contains numerous figures, tables, references, and worked example problems
CT scanning of the chest is one of the most important imaging modalities available to a pulmonologist. The advent of high-resolution CT scanning of the chest has led to its increasing use. Although ...chest radiographs are still useful as an initial test, their utility is limited in the diagnosis of lung diseases that depend on higher resolution images such as interstitial lung diseases and pulmonary vascular diseases. Several metaphoric chest CT scan signs have been described linking abnormal imaging patterns to lung diseases. Some of these are specific to a disease, whereas others help narrow the differential diagnosis. Recognizing these imaging patterns and CT scan signs are thus vitally important. In the present article, we describe a comprehensive list of the commonly encountered metaphoric chest CT scan signs and their clinical relevance.
Acute Ischemic Stroke González, R. Gilberto; Hirsch, Joshua A; Lev, Michael H ...
2011, 2006, 2010, 20100831, 2005-11-08
eBook
This updated second edition of Acute Ischemic Stroke: Imaging and Intervention provides a comprehensive account of the state of the art in the diagnosis and treatment of acute ischemic stroke. The ...basic format of the first edition has been retained, with sections on fundamentals such as pathophysiology and causes, imaging techniques and interventions. However, each chapter has been revised to reflect the important recent progress in advanced neuroimaging and the use of interventional tools. In addition, a new chapter is included on the classification instruments for ischemic stroke and their use in predicting outcomes and therapeutic triage. All of the authors are internationally recognized experts and members of the interdisciplinary stroke team at the Massachusetts General Hospital and Harvard Medical School. The text is supported by numerous informative illustrations, and ease of reference is ensured through the inclusion of suitable tables. This book will serve as a unique source of up-to-date information for neurologists, emergency physicians, radiologists and other health care providers who care for the patient with acute ischemic stroke.
IMPORTANCE: Medical imaging increased rapidly from 2000 to 2006, but trends in recent years have not been analyzed. OBJECTIVE: To evaluate recent trends in medical imaging. DESIGN, SETTING, AND ...PARTICIPANTS: Retrospective cohort study of patterns of medical imaging between 2000 and 2016 among 16 million to 21 million patients enrolled annually in 7 US integrated and mixed-model insurance health care systems and for individuals receiving care in Ontario, Canada. EXPOSURES: Calendar year and country (United States vs Canada). MAIN OUTCOMES AND MEASURES: Use of computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and nuclear medicine imaging. Annual and relative imaging rates by imaging modality, country, and age (children <18 years, adults 18-64 years, and older adults ≥65 years). RESULTS: Overall, 135 774 532 imaging examinations were included; 5 439 874 (4%) in children, 89 635 312 (66%) in adults, and 40 699 346 (30%) in older adults. Among adults and older adults, imaging rates were significantly higher in 2016 vs 2000 for all imaging modalities other than nuclear medicine. For example, among older adults, CT imaging rates were 428 per 1000 person-years in 2016 vs 204 per 1000 in 2000 in US health care systems and 409 per 1000 vs 161 per 1000 in Ontario; for MRI, 139 per 1000 vs 62 per 1000 in the United States and 89 per 1000 vs 13 per 1000 in Ontario; and for ultrasound, 495 per 1000 vs 324 per 1000 in the United States and 580 per 1000 vs 332 per 1000 in Ontario. Annual growth in imaging rates among US adults and older adults slowed over time for CT (from an 11.6% annual percentage increase among adults and 9.5% among older adults in 2000-2006 to 3.7% among adults in 2013-2016 and 5.2% among older adults in 2014-2016) and for MRI (from 11.4% in 2000-2004 in adults and 11.3% in 2000-2005 in older adults to 1.3% in 2007-2016 in adults and 2.2% in 2005-2016 in older adults). Patterns in Ontario were similar. Among children, annual growth for CT stabilized or declined (United States: from 10.1% in 2000-2005 to 0.8% in 2013-2016; Ontario: from 3.3% in 2000-2006 to −5.3% in 2006-2016), but patterns for MRI were similar to adults. Changes in annual growth in ultrasound were smaller among adults and children in the United States and Ontario compared with CT and MRI. Nuclear medicine imaging declined in adults and children after 2006. CONCLUSIONS AND RELEVANCE: From 2000 to 2016 in 7 US integrated and mixed-model health care systems and in Ontario, rates of CT and MRI use continued to increase among adults, but at a slower pace in more recent years. In children, imaging rates continued to increase except for CT, which stabilized or declined in more recent periods. Whether the observed imaging utilization was appropriate or was associated with improved patient outcomes is unknown.
Dandy-Walker Malformation Monteagudo, Ana
American journal of obstetrics and gynecology,
December 2020, 2020-12-00, 20201201, Letnik:
223, Številka:
6
Journal Article
This book provides an atlas of the normal human brain based on three dimensional reconstructions of magnetic resonance scans obtained in normal living adults as well as neurological patients with ...focal brain lesions. It provides detailed descriptions of sulci and gyri and illustrates how they appear in different brains. The book shows how different slice orientations obtained in the same brain produce different images that can be anatomically misinterpreted, in normal brains as well as brains with lesions. The book also addresses quantitative differences between the human brain and the brains of apes; gray and white matter differences between the hemispheres; and differences related to gender, age, and congenital deafness.
Acute dyspnea is a common symptom in the ED. The standard approach to dyspnea often relies on radiologic and laboratory results, causing excessive delay before adequate therapy is started. Use of an ...integrated point-of-care ultrasonography (PoCUS) approach can shorten the time needed to formulate a diagnosis, while maintaining an acceptable safety profile.
Consecutive adult patients presenting with dyspnea and admitted after ED evaluation were prospectively enrolled. The gold standard was the final diagnosis assessed by two expert reviewers. Two physicians independently evaluated the patient; a sonographer performed an ultrasound evaluation of the lung, heart, and inferior vena cava, while the treating physician requested traditional tests as needed. Time needed to formulate the ultrasound and the ED diagnoses was recorded and compared. Accuracy and concordance of the ultrasound and the ED diagnoses were calculated.
A total of 2,683 patients were enrolled. The average time needed to formulate the ultrasound diagnosis was significantly lower than that required for ED diagnosis (24 ± 10 min vs 186 ± 72 min; P = .025). The ultrasound and the ED diagnoses showed good overall concordance (κ = 0.71). There were no statistically significant differences in the accuracy of PoCUS and the standard ED evaluation for the diagnosis of acute coronary syndrome, pneumonia, pleural effusion, pericardial effusion, pneumothorax, and dyspnea from other causes. PoCUS was significantly more sensitive for the diagnosis of heart failure, whereas a standard ED evaluation performed better in the diagnosis of COPD/asthma and pulmonary embolism.
PoCUS represents a feasible and reliable diagnostic approach to the patient with dyspnea, allowing a reduction in time to diagnosis. This protocol could help to stratify patients who should undergo a more detailed evaluation.
Objectives
To assess the added-value of systematic unenhanced abdominal computed tomography (CT) on emergency department (ED) diagnosis and management accuracy compared to current practice, in ...elderly patients with non-traumatic acute abdominal symptoms.
Methods
Institutional review board approval and informed consent were obtained. This prospective study included 401 consecutive patients 75 years of age or older, admitted to the ED with acute abdominal symptoms, and investigated by early systematic unenhanced abdominal CT scan. ED diagnosis and intended management before CT, after unenhanced CT, and after contrast CT if requested, were recorded. Diagnosis and management accuracies were evaluated and compared before CT (clinical strategy) and for two conditional strategies (current practice and systematic unenhanced CT). An expert clinical panel assigned a final diagnosis and management after a 3-month follow-up.
Results
Systematic unenhanced CT significantly improved the accurate diagnosis (76.8% to 85%,
p
=1.1x10
-6
) and management (88.5% to 95.8%,
p
=2.6x10
-6
) rates compared to current practice. It allowed diagnosing 30.3% of acute unsuspected pathologies, 3.4% of which were unexpected surgical procedure requirement.
Conclusions
Systematic unenhanced abdominal CT improves ED diagnosis accuracy and appropriate management in elderly patients presenting with acute abdominal symptoms compared to current practice.
Key Points
•
Systematic unenhanced CT improves significantly diagnosis accuracy compared to current practice.
•
Systematic unenhanced CT optimizes appropriate hospitalization by increasing the number of discharged patients.
•
Systematic unenhanced CT allows detection of about one-third of acute unsuspected abdominal conditions.
•
It should allow boosting emergency department management decision-making confidence in old patients.
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