Daniele Andreini MD, Presenter: Nothing to Disclose

Gianluca Pontone MD, Abstract Co-Author: Nothing to Disclose

Saima Mushtaq, Abstract Co-Author: Nothing to Disclose

Antonio Bartorelli, Abstract Co-Author: Nothing to Disclose

Erika Bertella, Abstract Co-Author: Nothing to Disclose

Edoardo Conte, Abstract Co-Author: Nothing to Disclose

Daniela Trabattoni, Abstract Co-Author: Nothing to Disclose

Giovanni Ballerini, Abstract Co-Author: Nothing to Disclose

Mauro Pepi, Abstract Co-Author: Nothing to Disclose

Purpose: The assessment of coronary stents with present-generation 64-detector row computed tomography scanners that use filtered backprojection and operating at standard definition of 0.5–0.75 mm (standard definition, SDCT) is limited by imaging artifacts and noise. We evaluated the performance of a novel, high-definition 64-slice CT scanner (HDCT), with improved spatial resolution (0.23 mm) and applied statistical iterative reconstruction (ASIR) for the diagnosis of coronary in-stent restenosis (ISR) in comparison with the performance of SDCT. The gold standard was defined by quantitative coronary angiography and intravascular ultrasound (IVUS).

Methods: Sixty-one consecutive patients scheduled for ICA for suspected ISR were enrolled. Thirty were studied using HDCT with ASIR algorithm and 31 using SDCT. In all patients, prospective ECG-triggering was used. After MDCT, each stent was classified as “evaluable” or “unevaluable”. Obstructive ISR was visually and quantitatively determined in evaluable stents. Correlations between quantitative MDCT and quantitative coronary angiography were estimated. In a subgroup, MDCT and IVUS measurements were correlated. The individual radiation dose exposure was estimated.

Results: The overall stent evaluability was higher using HDCT in comparison with SDCT (96% vs. 92%). Artifact sub-analysis showed a significantly lower number of blooming artefact using HDCT. In the segment-based analysis, sensitivity, specificity and accuracy of MDCT for ISR identification were significantly higher in HDCT group (100%, 98% and 98%, respectively) than in SDCT group (92%, 94% and 93%, respectively). The correlations between percent of stenosis evaluated by HDCT vs. QCA and IVUS (r= 0.905 and r= 0.945, respectively) were higher than correlations between percent of stenosis evaluated by SDCT vs. QCA and IVUS (r=0.742 and r= 0.768, respectively). The correlation between in-stent minimal lumen area (MLA) evaluated by HDCT vs. IVUS (r= 0.901) was higher than correlation between MLA evaluated by SDCT vs. IVUS (r=0.756). HDCT group was exposed to a lower radiation dose compared to SDCT group (2.1±0.6  vs. 4.4±1.4 mSv).

Conclusions: HDCT with ASIR can greatly improve diagnostic accuracy of quantitative non-invasive evaluation of coronary stents with a significant reduction of radiation exposure.

HDCT with ASIR can greatly improve evaluation of coronary stents

Andreini, D, Pontone, G, Mushtaq, S, Bartorelli, A, Bertella, E, Conte, E, Trabattoni, D, Ballerini, G, Pepi, M, Quantitative Evaluation of Coronary In-Stent Restenoses with Gemstone High Definition CT in Comparison with Quantitative Coronary Angiography and Intravascular Ultrasound: Preliminary Results.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11007987.html