Comparative Study Of Coronary CT And MR Angiography In Evaluation Of Coronary Stenosis And Atherosclerotic Plaque

Part 1:TITLE Comparative study of coronary CT and MR angiography for coronary artery stenosis.PURPOSE To compare 16 slice Multi-detector CT (16-MDCT) and Breathhold 3D MR coronary angiography in the visualization of coronary arteries and the accuracy of detecting significant stenosis (> 50%) in patients with suspected coronary artery disease.MATERIAL AND METHODS Forty patients were examined with coronary CTA and MRA within 3 days, 31 of them underwent conventional coronary angiography (CAG) within 2 weeks after CTA and MRA examination. CTA was performed by using a 16-MDCT scanner with 16x1.25 mm detector collimation, 0.5s rotation time. MRA was performed on a 1.5 T MR scanner with breathhold 3D FIESTA: TR 4.0 ms, TE 1.7 ms, flip angle 65° , slice thickness 3 mm, FOV 280 mm, matrix 256x192, NEX 0.5. Mean heart rate of the 40 patients was 63±5.8 bpm in CTA examination and β-blocker was taken in 26 patients. CTA and MRA image quality was evaluated in 9 coronary segments (RCA₁, RCA2, RCA3, LM, LAD₁, LAD2, LAD3, LCX₁, LCX2) by two experienced radiologists in concensus using a four-point grading scale. Sensitivity, specificity, positive predictive value and negative predictive value of CTA and MRA were calculated for detection of significant stenosis.RESULTS CTA showed higher image quality in most coronary segments except middle RCA (p<0.05). significant stenosis was detected in 43 segments on CAG, 36 and 27 of the 43 segments were correctly diagnosed by CTA and MRA, respectively. Sensitivity, specificity, positive predictive value, and negativepredictive value of CTA and MRA in detecting significant stenosis on a segmental basis were 83 %, 84 %, 49 %, 97 % and 63 %, 90 %, 55 %, 93 %, respectively.CONCLUSIONS Coronary CTA showed higher image quality in most coronary segments except for middle RCA. CTA had higher sensitivity for detection of coronary significant stenosis, whereas coronary MRA had higher specificity. Both CTA and MRA showed high negative predictive value, which is useful for excluding coronary stenosis in symptomatic patients.Part 2:TITLE Comparative Study of Coronary Atherosclerotic Plaque: CTA versus MRAPURPOSE To compare the accuracy of coronary CTA and MRA in detecting significant stenosis (>50%) caused by different composition plaques.MATERIAL AND METHODS Thirty patients were examined with coronary CTA, MRA and conventional coronary angiography (CAG) within two weeks. CTA and MRA were performed with a 16-slice CT scanner and on a 1.5 T MR scanner with breathhold 3D FIESTA sequence respectively. The coronary plaques were grouped as non-calcified and calcified plaque on CTA images. The accuracy and agreement of CTA and MRA in detecting significant stenosis were evaluated by two experienced radiologists independently using CAG as reference.RESULTS Fifty-three plaques were detected on CTA. 28 were non-calcified and the other 25 were calcified. 21 of 28 non-calcified plaques caused significant stenosis on CAG The sensitivity and specificity of CTA and MRA in detecting significant stenosis were 18/21, 6/7 and 10/21, 5/7, repectively, CTA showed good agreement with CAG (k = 0.65). Six of 25 calcified plaques caused significant stenosis on CAG The sensitivity and specificity of CTA and MRA in detecting significant stenosis were 5/6, 6/19 and 5/6, 14/19, repectively, MRA showed moderate agreement with CAG (k = 0.46).CONCLUSIONS CTA is accurate for detecting significant stenosis caused by non-calcified plaque, while MRA has the advantage of evaluating lumen with severe calcified plaque.