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Thứ Bảy, 2 tháng 3, 2013

RadioGraphics 1-2/2013






Selected Abstracts

1.     Abstract 1

o   Lilian C. Wang, Megan Sullivan, Hongyan Du, Marina I. Feldman, and Ellen B. Mendelson

Continuing Medical Education: US Appearance of Ductal Carcinoma in Situ Radiographics January-February 2013 33:1 213-228; doi:10.1148/rg.331125092

US features of calcified DCIS, noncalcified DCIS, and DCIS diagnosed at MR imaging–directed (“second-look”) US are discussed, along with optimal imaging technique, relevant pathologic findings, and the diagnostic utility of US in the detection of DCIS.

2.     Abstract 2

o   George C. Kagadis, Alisa Walz-Flannigan, Elizabeth A. Krupinski, Paul G. Nagy, Konstantinos Katsanos, Athanasios Diamantopoulos, and Steve G. Langer

Medical Imaging Displays and Their Use in Image Interpretation Radiographics January-February 2013 33:1 275-290; doi:10.1148/rg.331125096

Display technology, the configuration and maintenance of displays for optimal medical image viewing, and viewing strategies to improve diagnostic performance are discussed.

3.     Abstract 3

o   Jonathan D. Kirsch, Mahan Mathur, Michele H. Johnson, Gunabushanam Gowthaman, and Leslie M. Scoutt

Continuing Medical Education: Advances in Transcranial Doppler US: Imaging Ahead Radiographics January-February 2013 33:1 E1-E14; doi:10.1148/rg.331125071

Recent advances in transcranial Doppler US are reviewed, and the advantages of gray-scale, color Doppler flow, and spectral Doppler imaging over the older “blind” study based on pulsed Doppler imaging are demonstrated.

1/ US Appearance of Ductal Carcinoma in Situ

Ductal carcinoma in situ (DCIS) is a noninvasive cancer that accounts for 25% of all breast cancers diagnosed in the United States. DCIS is a heterogeneous disease process with varied clinical manifestations and a broad spectrum of imaging findings. With advances in technology, the ability to detect early-stage cancers has improved, and understanding the role of ultrasonography (US) in the multimodality era of detection and diagnosis is paramount. When calcifications are identified at mammography, US can be performed to evaluate for an invasive component and to allow possible US-guided biopsy. Use of high-frequency transducers, spectral compounding, and speckle reduction algorithms can aid in the detection of calcifications. Calcified DCIS most commonly manifests as echogenic foci located within a mass or duct, associated with internal microlobulations, or distributed in a branch pattern. Noncalcified DCIS, which is more often identified in symptomatic patients, may manifest as a hypoechoic mass with microlobulated margins and no posterior acoustic features, or it may have a “pseudomicrocystic” appearance. Harmonic imaging and coronal reconstruction may improve detection of noncalcified DCIS. The appearance of DCIS at “second-look” US can be subtle and may warrant a lower threshold for detection, given a higher pretest probability of malignancy. US features are nonspecific, and careful correlation with respect to lesion location, size, shape, and depth is needed. The presence of internal vascularity can help increase the positive predictive value of US in this setting. US is a useful adjunct to mammography and magnetic resonance imaging, and recognizing the US appearance of DCIS will aid in the detection and diagnosis of this disease entity.

o    Received May 1, 2012.
o    Revision requested May 31, 2012.
o    Revision received July 16, 2012.
o    Accepted September 14, 2012.

2/ Medical Imaging Displays and Their Use in Image Interpretation

The adequate and repeatable performance of the image display system is a key element of information technology platforms in a modern radiology department. However, despite the wide availability of high-end computing platforms and advanced color and gray-scale monitors, the quality and properties of the final displayed medical image may often be inadequate for diagnostic purposes if the displays are not configured and maintained properly. In this article—an expanded version of the Radiological Society of North America educational module “Image Display”—the authors discuss fundamentals of image display hardware, quality control and quality assurance processes for optimal image interpretation settings, and parameters of the viewing environment that influence reader performance. Radiologists, medical physicists, and other allied professionals should strive to understand the role of display technology and proper usage for a quality radiology practice. The display settings and display quality control and quality assurance processes described in this article can help ensure high standards of perceived image quality and image interpretation accuracy.

o    Received May 4, 2012.
o    Revision requested May 31, 2012.
o    Revision received July 18, 2012.
o    Accepted July 31, 2012.

3/ Advances in Transcranial Doppler US: Imaging Ahead

Transcranial Doppler ultrasonography (US) is a noninvasive, portable technique for evaluating the intracranial vasculature. It has found its most useful clinical application in the detection of vasospasm involving the cerebral vessels after subarachnoid hemorrhage due to aneurysm rupture. The technique has become an integral part of monitoring and managing patients with subarachnoid hemorrhage in the neurologic intensive care unit. In addition, it has proved useful for evaluating the intracranial vasculature in patients with sickle cell disease, stroke, or brain death. Transcranial US originated as a “blind” nonimaging study in which pulsed Doppler technology was used. Identification of the major intracranial vessels and evaluation of those vessels for vasospasm relied on spectral waveforms obtained in each vessel and was based on the depth of the vessel from the skull, the direction of blood flow, and the orientation of the transducer. Recent advances in US technology allow the use of gray-scale, spectral Doppler, and color Doppler flow imaging to directly visualize intracranial vessels, thereby simplifying flow velocity measurements and enhancing their accuracy for vasospasm detection. In particular, measurements of peak systolic velocity and mean flow velocity and calculation of the Lindegaard ratio facilitate the identification of vessels that may be in vasospasm and help differentiate vasospasm from physiologic conditions such as hyperemia and autoregulation. Thus, gray-scale and color Doppler flow imaging offer many advantages over the original pulsed Doppler technique for evaluating the intracranial vasculature.

o    Received April 16, 2012.
o    Revision requested May 31, 2012.
o    Revision received August 6, 2012.
o    Accepted August 10, 2012

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