1,721,026 research outputs found
Imaging of the Kidney in the Critically Ill and Acute Renal Failure. Ultrasonography and Doppler Techniques in Acute Kidney Injury
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Emergency Ultrasound in Trauma Patients: Beware of Pitfalls and Artifacts!
No full textBackground: Ultrasonography (US) is highly dependent on operators’ skills. It is not only a matter of correct scan techniques; there are anatomical structures and variants, as well as artifacts, which can produce images difficult to interpret and which, if not properly understood, can be causes of errors. Objectives: This paper will review relatively common US pitfalls and artifacts that can be encountered in trauma patients and will offer tips to recognize and avoid them. Discussion: Normal anatomical structures and anatomical variants can mimic fluid collections or perisplenic lesions. Examination along multiple scan planes, real-time observation of movements or repetition of the study after the patient has drunk some fluid or after placing a finger on her/his body wall can help proper identification. The term artifact in US imaging refers to display phenomena not properly representing the imaged structures. This can result in images suggesting fracture lines within organs or at their borders, lung consolidations, or pleural effusions, and abdominal fluid collections. Their knowledge is the first step to recognize them; then, use of multiple scan planes or repetition of the study after voiding or changes of equipment setting can make them disappear or clarify their nature. Conclusion: We present possible anatomic pitfalls and artifacts that may affect correct interpretation of US images in patients with abdominal trauma and suggest how to avoid or to clarify them during the examination. Knowing their existence, their appearances, and the reasons why they are produced is important for proper use of this diagnostic technique
Lithiasis-induced acute kidney injury: Is ultrasonography enough?
Full text linkObstructive acute kidney injury(AKI) is relatively common, reported in 8% to 17% of cases presenting with community-acquired AKI. It is more frequent in males of advanced age, usually from bladder outlet obstruction. Guidelines recommend imaging, namely a renal tract ultrasound (US), within 24 hours from admission to rule-out obstruction and guarantee recovery of renal function. Lithiasis is not a common cause of AKI (1–2% of obstructive cases) and it is reported that only 0.72% of patients with urinary calculi develop AKI from stones. It is known that US may have difficulties in demonstrating stones-related obstructionand that unenhanced CT ismost sensitive and specific for this purpose. We report therefore the imaging findings in a series of patients with lithiasis-induced AKI to understand the respective roles of these techniques
Monitoring of fracture calluses with color Doppler sonography
No full textPurpose. Fracture callus formation is closely associated with vascular invasion, and the use of color Doppler sonography has been suggested as a means to monitor, earlier than gray-scale sonography, the first stages of the healing process. We report the findings in a series of patients with tibial fractures in whom both gray-scale sonography and color Doppler imaging were employed to monitor new bone formation at the fracture site. Methods. Twenty patients with tibial fractures treated with external fixator frames were examined sonographically about 10 days after surgery and then about every 25 days until radiographic demonstration of consolidation. Results. Eighteen of 20 patients had a well-developed callus, while the remaining 2 patients showed delayed fracture healing. In patients with normal callus development, color Doppler imaging demonstrated the progressive formation of new vessels until about 100 days from the surgery; at subsequent examinations, flow signals decreased, and bone remodeling was confirmed by conventional radiography and gray-scale sonography. The resistance indices in these patients tended to decrease in the early weeks after surgery and then slightly increased. In contrast, lack of development of flow signals and persistence of high resistance indices were observed in the 2 patients with delayed fracture healing. Conclusions. Color Doppler sonography seems to have the capability to predict whether the development of fracture calluses will be normal or delayed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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