Keywords:
Vascular, Arteries / Aorta, Extremities, CT-Angiography, Radiation safety
Authors:
E. Kondratyev, G. Karmazanovsky; Moscow/RU
DOI:
10.1594/ecr2013/B-0250
Purpose
MDCT angiography is an accurate,
non-invasive technique for assessing the presence and extent of peripheral arterial occlusive disease. The sensitivity and specificity of MDCT angiography are 95% and 96%,
respectively [1].
The diagnostic applications of MDCT angiography have extremely improved considerably because of its high spatial resolution,
the use of fast contrast material injection rates,
novel reconstruction algorithms and postprocessing tools.
However MDCT angiography has some critical disadvantages such as sensitivity to number of artifacts and especially radiation dose that is a persistent problem with modern MDCT.
A strategy for reducing radiation dose at CTA involves lowering the tube voltage or tube current.
Recent studies showed statistically significant decreasing of radiation dose while reducing tube voltage or current without deterioration of vascular enhancement and image quality [2,3].
But some of these studies have potential limitation,
they were performed in patients with normal or slightly elevated body mass index (BMI≤25).
Whether results of these studies are applicable to populations of larger patients should be verified.
In addition two main types of low-dose protocols should be compared.
Recently new reconstruction algorithms such as iterative reconstruction have become widespread. Iterative reconstruction is an alternative to filtered back projection (FBP) reconstruction methods.
Investigations to determine image quality at thoracic and coronary CT using these methods had already demonstrated decreased image noise and its potential for radiation dose reduction [4-8].
But in most cases special reconstruction algorithms is an expensive option for MDCT and in some cases could not be used with previous generation of CTs.
This is an important limitation factor.
However low-dose protocol should be used despite of absence of special reconstruction algorithms.
The purpose of our study was to compare two low-dose scanning protocols reconstructed using standard algorithm (FBP),
and to estimate their effects on the signal,
noise,
effective radiation dose (ED),
quality of acquired data.