Digital subtraction angiography in congenital heart disease in pediatric patients

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Subtraction techniques to suppress bony and soft tissue structures in areas of angiographic interest are now used with increasing frequency. Advances in digital image processing combined with angiography have achieved high contrast sensitivity (as in computed tomography), enabling retrieval of information previously not available. Data may be converted to timed physiologic studies as well as anatomic images. We report the results of our initial experience with digital subtraction angiography (DSA) in 50 patients with congenital heart disease.

Materials and methods

Imaging equipment and technique

Data were obtained with a commercially available DSA unit (DR-960, Technicare Corporation, Solon, Ohio), which produces multiple sequential views of the cardiovascular system (Fig. 1). All images were made in the single-mask mode. A typical radiographic sequence utilized 80–100 kVp, 5–10 mAs/frame (2–10 msec at 1000 mA), and up to 6 frames/sec for 15 seconds. A single “best” mask was selected for immediate postprocessing. The image display was 256 × 256 × 256 shades of gray.

Flow analysis

The region of interest curves were generated via keyboard-accessed flow analysis programs and the pixel values plotted against time after appropriate corrections for background. Pixel values represent change in x-ray attenuation by amount of iodine in the region of interest. These values reflect the product of iodine concentration and vessel diameter provided appropriate corrections for radiation scatter and veiling glare are made. In our studies, however, these corrections were not applied and the data represent approximation of iodine concentration in the regions of interest suitable . . .



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