Elsevier

Clinical Radiology

Volume 60, Issue 1, January 2005, Pages 85-95
Clinical Radiology

Multidetector row CT angiography of the lower limb arteries: a prospective comparison of volume-rendered techniques and intra-arterial digital subtraction angiography

https://doi.org/10.1016/j.crad.2004.07.011Get rights and content

AIM

To assess whether multi-detector CT angiograms (MDCTA) of the lower limb arteries, compared with conventional digital subtraction angiograms (DSA), could replace invasive arteriography in patients with symptomatic peripheral arterial disease.

MATERIALS AND METHODS

In a prospective comparative analysis of MDCTA and DSA in 44 patients, MDCTA was analyzed using volume-rendered images acquired at a workstation and viewed in tandem with the original axial data. Designated arterial segments were graded according to their degree of stenosis.

RESULTS

We found agreement for the degree of stenosis in 88.8% and 85.4% of 1024 segments analysed for two observers. The sensitivity for treatable lesions (>50% stenosis) was 79.1% and 72% with a specificity of 93.3% and 92.6%. DSA failed to visualize 7.3% of segments that were visible with MDCTA. These segments were exclusively downstream to long segment occlusions.

CONCLUSION

MDCTA using 4-slice machines is insensitive to detecting significant arterial stenoses in the lower limb arteries. MDCTA is superior to DSA in its visualization of arterial territories downstream to significant occlusive disease.

Introduction

The feasibility of imaging the entire lower limb vasculature by multidetector row CT angiography (MDCTA) was first reported by Rubin et al.1 Before this, reliable depiction of the more distal vessels with single-detector spiral scanners had been limited by slow image acquisition and poor z-axis resolution.2, 3, 4 Using four-slice detector technology with 2–3 mm reconstructed slice thickness generally produces 800–1200 images, depending upon patient height.5 This amount of information creates significant demands upon post-processing software algorithms.

Three recent prospective comparative studies6, 7, 8 of MDCTA with conventional angiography report high sensitivities and specificities for the detection of significant stenotic or occlusive disease. These studies used combinations of volume-rendered techniques, maximum intensity projection (MIP) algorithms and multiplanar reformats (MPRs) for the analysis of MDCTA axial data. The post-processing time, where reported, was 45–50 min in addition to a scanning time of 15–20 min.

The purpose of this study was to evaluate the accuracy of MDCTA when analyzed using a rapidly acquired volume-rendered image in conjunction with the axial data. If the speed and reproducibility of MDCTA could be capitalized upon with rapid post-processing, thus enabling adequate presentation of data in an angiographical format, then revascularization planning could all be performed non-invasively.

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Subjects and methods

Between July 2002 and March 2003, 44 individuals with symptomatic peripheral vascular disease, undergoing diagnostic DSA, also underwent prior MDCTA. All MDCT angiograms were obtained 12–72 h before planned DSA. All participants signed informed consent forms approved by our local research and ethical committee.

We recruited 30 men and 14 women (average age 68.1 years, range 51–90 years). Of these, 29 were referred for short-distance disabling claudication (SCVIR category 3),9 6 had rest pain

Results

MDCTA was well tolerated by all 44 participants. Adequate vascular enhancement was achieved in all cases, enabling production of volume-rendered images. Of the DSA examinations, 13 involved antegrade arteriography before infrainguinal angioplasty. Of the remaining 31, 29 included retrograde femoral arterial punctures with subsequent examination of both legs. Two subjects required radial artery puncture to obtain images of the lower limb vasculature because of severe aortoiliac occlusive

Discussion

The advent of multidetector row CT technology and its rapid introduction throughout Europe and the USA has led to a massive interest in CT as a viable technique for non-invasive vascular imaging. The superior scan coverage possible with multidetector CT scanners is ideally suited to the lower limb arteries, with scan lengths of up to 1.5 m being completed in less than 35 s.10

There is no doubt that current hardware using 4-slice and more recently 16-slice technology is capable of imaging the

Acknowledgements

We thank S. Shaw, Department of Mathematics and Statistics, University of Plymouth, for his help with statistical analysis.

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This study is supported by the Northcott Foundation, Devon, and a “Brunel” Pump priming grant from Derriford Hospital Radiology Department.

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