Quantitive evaluation of coronary artery stenosis and in-stent restenosis by 64-slice spiral CT angiography and DSA

Objective: To evaluate the diagnostic accuracy and reliability for coronary artery stenosis and in-stent restenosis detection using 64-slice spiral computed tomography( multislice CT, MSCT) angiography and digital subtraction angiography (DSA). Methods: A pulsating cardiac phantom with two simulated coronary arteries was scanned on a 64-slice CT scanner and underwent DSA at static state, at 4 different sinus rhythms of 0, 50, 70, and 90 beats per minute (bpm). One simulated artery was 3 mm in lumen diameter with 3 segments of 25%, 50%, and 75% stenoses. A stent with 2 segments of 50% and 75% stenoses was placed into the other artery with 4mm in lumen diameter. Images from MSCT were analyzed and compared with those from DSA. Results: (1) The mean values of the 25%, 50%, and 75% stenoses measured with MSCT were (30.0±1.4)%, (49.5±1.3)%, and (72.9±3.9)%, respectively (P values were 0.005, 0.531, and 0.369 respectively). The mean values of the 25%, 50%, and 75% stenoses measured with DSA were (24.8±2.0)%, (48.2±2.1)%, (75.3±2.4)% respectively (P values were 0.883, 0.180, and 0.796, respectively). (2) MSCT was susceptible to heart rate, with artifact increasing as heart rate increasing, especially when the heart rate were ≥70 bpm. (3) There was a good correlation between 64-slice MSCT and DSA (r=0.995, P=0.000). (4) 64-slice MSCT could show the stent and in- stent restenosis simutaneously. Its capability to depict in-stent restenosis was limited. The depiction rate of 50% in- stent restenosis were (46.4±4.5)% (0 bpm) and (43.6±5.7)% (50 bpm) respectively (P<0.05). DSA could depict the in-stent stenosis but could not show the morphology of the stent. Conclusion: 64-slice MSCT is reliable in detecting coronary artery stenosis. MSCT has clinical application value due to its non-invasive nature. Even though its capability is somewhat limited in depicting in-stent restenosis, MSCT is promising in the cases when vessel caliber is relatively large and heart rate is relatively low. (authors)