Spiral CT angiography of the abdomen

Abstract

Computed tomographic angiography (CTA) is a minimally invasive technique for vascular imaging with the potential to become the primary imaging method for many angiographic applications in the abdomen. It is based on the rapid volume acquisition capabilities of spiral (or helical) CT and uses a properly timed intravenous contrast bolus to obtain a three-dimensional data set from the examined vascular region. This data set, consisting of overlapping transaxial CT images, can be interactively reviewed using arbitrary cut planes (multiplanar reformats), or it can be transformed into angiographic displays using maximum intensity projections (MIP) or three-dimensional shaded surface displays (SSD).Although there is an absolute limit to spatial resolution with CTA that precludes diagnostic assessment of abdominal vessels smaller than 1 mm, CTA has been shown to be an excellent tool for imaging the abdominal aorta and its large side branches [1][2][3][4][5]. Advantages over arterial angiography include use of the intravenous approach, direct information derived about vascular walls and perivascular structures, and the use of three-dimensional visualization techniques. With its fast acquisition time and relatively high spatial resolution, CTA compares favorably with MR angiography (MRA) and color-coded duplex ultrasonography. However, in contrast to these techniques, CTA images display only anatomic information and lack flow sensitivity.Although the basic idea of CTA is simple, there are numerous factors that influence image quality and may cause artifacts. Attention must be paid to scanning technique and contrast application in order to achieve diagnostic images of optimum quality. We describe our experience with more than 500 abdominal CT angiograms since 1991, discuss new developments in scan-

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CT angiography of the abdominal arteries

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“…Table 1 shows a number of examples for a 0.75-s scanner. Scan protocols for 1-s scanners can be found in previous publications [3].…”

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Preoperative value of CT angiography in the laparoscopic removal of rudimentary uterine horn

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