64-slice multidetector coronary CT angiography: in vitro evaluation of 68 different stents.
The purpose of this study was to test a large sample of different coronary artery stents using four image reconstruction approaches with respect to lumen visualization, lumen attenuation, and image noise in 64-slice multidetector-row computed tomography (MDCT) in vitro and to provide a catalogue of currently used coronary artery stents when imaged with state-of the-art MDCT. We examined 68 different coronary artery stents (57 stainless steel, four cobalt-chromium, one cobalt-alloy, two nitinol, four tantalum) in a coronary artery phantom (vessel diameter 3 mm, intravascular attenuation 250 HU, extravascular density -70). Stents were imaged in axial orientation with standard parameters: 32 x 0.6 collimation, pitch 0.24, 680 mAs, 120 kV, rotation time 0.37 s. Four different image reconstructions were obtained with varying convolution kernels and section thicknesses: (1) soft, 0.6 mm, (2) soft, 0.75, (3) medium soft, 0.6, and (4) stent-optimized sharp, 0.6. To evaluate visualization characteristics of of the stent, the lumen diameter, intraluminal density and noise were measured. The high-resolution kernel offered significantly better average lumen visualization (57% +/-10%) and more realistic lumen attenuation (222 HU +/-66 HU) at the expense of increased noise (15.3 HU +/-3.7 HU) compared with the soft and medium-soft CT angiography (CTA) protocol (p<0.001 for all). Stents with a lumen visibility of more than 66% were: Arthos pico, Driver, Flex, Nexus2, S7, Tenax complete, Vision (all 67%), Symbiot, Teneo (70%), and Radius (73%). Only ten stents showed a lumen visibility of less than 50%. Stent lumen visibility largely varies depending on the stent type. Even with the improved spatial resolution of 64-slice CT, a stent-optimized kernel remains beneficial for stent visualization when compared with the standard medium-soft CTA protocol. Using 64-slice CT and high-resolution kernel, the majority of stent products show a lumen visibility of more than 50% of the stent diameter.
Maintz
David
D
Department of Clinical Radiology, University of Muenster, Germany. maintz@uni-muenster.de
Seifarth
Harald
H
Raupach
Rainer
R
Flohr
Thomas
T
Rink
Michael
M
Sommer
Torsten
T
Ozgün
Murat
M
Heindel
Walter
W
Fischbach
Roman
R
D000497:Alloys; D000704:Analysis of Variance; D002857:Chromium; D003035:Cobalt; D017023:Coronary Angiography; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D066298:In Vitro Techniques; D019047:Phantoms, Imaging; D013193:Stainless Steel; D015607:Stents; D013635:Tantalum; D014057:Tomography, X-Ray Computed
D000497:Alloys; D002857:Chromium; D013193:Stainless Steel; C013616:nitinol; D003035:Cobalt; D013635:Tantalum