The Evaluation Of Coronary Plaque Characteristics By Gemstone Spectral CT

Objective: To explore the capability and clinical value of Gemstone Spectral CT coronaryangiography in inspecting plaque in coronary artery.Methods: 56 patients who diagnosed coronary artery disease from Jun 2011 to November2011 in our hospital were divided into 2 groups according to clinical symptoms：stable anginapectoris group(SAP) and acute coronary syndrome group(ACS). All patients undergoneGemstone Spectral CT coronary angiography examination. The patients whose heart rate wasslow were taken prospective ECG gating axial scan and the patients whose heart rate was toofast were taken retrospective ECG gating helical scan. Plaque types and remodeling wasanalyzed on CTCA images on a per-segment basis(15-segment AHA classification). Plaquetypes were classified as calcified (type1), mixed(predominantly calcified ) (type2),mixed(predominantly non-calcified ), (type3), and non-calcified (type4). Plaques remodeling isdivided into positive remodeling and negative remodeling. To evaluate the coronary arterystenosis degree of the two groups of patients ’.The coronary artery stenosis degree is dividedinto 4 levels: mild(<50%), medium(50%~75%), severe narrow(75%~99%)，and block>99%。Analyze and compare plaque types, plaque remodeling and the degree of coronary arterystenosis. Calculate and analyze the patients ’ radiation dose.Results:1. In the 56 patients, SAP group contains 24 patients, ACS group contains 32 patients. 172plaques were detected on CTA in SAP group, 141 were calcified plaques, 12 were mixedplaque(predominantly calcified)，3 were mixed plaques(predominantly non-calcified), and theother 16 were non-calcified Plaques. 183 plaques were detected on CTA in ACS group, 89 werecalcified plaques, 6 were mixed plaques(predominantly calcified), 21 were mixed plaques(predominantly non-calcified), and the other 67 were non-calcified Plaques. The calcifiedplaques and mixed plaques（predominantly calcified）predominated in SAP group, whereas thenon-calcified plaques and mixed plaques (predominantly non-calcified) predominated in ACSgroup. The difference of plaque types between SAP group and ACS group had statisticalsignificance (P<0.05). Non-calcified plaque and mixed plaque（predominantly non-calcified）andcoronary heart disease risk has a significant correlation(P＜0.05).2. The difference of plaque remodeling between two groups had statistical significance(P<0.05). Positive remodeling predominated in ACS group, whereas negative remodeling predominated in ACS group.3. There was no statistical significant difference of the degree of coronary artery stenosisbetween two groups (P<0.05).4. In the 56 patients, 35 patients were taken prospective ECG gating axial scan , the averageED was 4.15±0.43 mSv. The other 21 patients were taken retrospective ECG gating helical scan,the average ED was 9.46±1.07 mSv. ED decreased by 56.13% in research group compared withthat of control group.Conclusions: Gemstone Spectral CT can identify soft and hard plaque through measuringthe CT value of the plaques, analyzing the situation of plaque remodeling and calcificationfeature. It can determine plaque stability, and thus guide clinical treatment. Gemstone SpectralCT can reduces the radiation dose greatly. It’s an convenient, noninvasive test technology.