Quantitative assessment of in‐stent dimensions: A comparison of 64 and 16 detector multislice computed tomography to intravascular ultrasound

Abstract

OBJECTIVES: To determine the utility of multislice computed tomography (MSCT) technology to evaluate coronary stent luminal diameter. BACKGROUND: Stent metal induced "blooming" artifact makes quantitative coronary angiography by MSCT difficult. There is a paucity of data on the efficacy of using 64 and 16 detector MSCT in evaluating coronary stents. METHODS: We evaluated four commercially available bare metal and polymer coated drug eluting stents using 64 and 16 detector MSCT for the following: (1) Strut density in Hounsfield's Units (Hu) using a 2 mm MIP; (2) In-stent luminal diameter (ISLD) measured by MSCT compared to intravascular ultrasound (IVUS). RESULTS: Increased strut thickness did not correlate with greater strut density as measured in Hu (R(2) = 0.05, P = 0.29). The ISLD by 16 MSCT vs. IVUS is: Vision 1.63 +/- 0.58 mm vs. 2.8 +/- 0.0; Cypher 1.80 +/- 0.00 vs. 2.9 +/- 0.0; Taxus 1.87 +/- 0.58 vs. 2.9 +/- 0.0; Liberté 1.80 +/- 0.10 vs. 3.0 +/- 0.1 (P < 0.01). ISLD determined by 64 MSCT vs. IVUS is: Vision 1.73 +/- 0.06 mm vs. 2.8 +/- 0.0; Cypher 1.87 +/- 0.12 vs. 2.9 +/- 0.0; Taxus 1.77 +/- 0.06 vs. 2.9 +/- 0.0; Liberté 1.80 +/- 0.10 vs. 3.0 +/- 0.1 (P < 0.01). CONCLUSIONS: When compared to IVUS measurements, MSCT results in a significant, underestimation of ISLD. This consistent underestimation (even with 64 MSCT) limits the applicability of CT angiography to quantify in-stent restenosis.