Abstract 2202: Noninvasive heart rate- independent Coronary Angiography using a new Dual x-ray Source CT
Multi-Slice CT allows to identify coronary stenoses with high diagnostic accuracy. Its major limitation is the inability to generate motionfree images in the presence of heart rates > 70 bpm. In the present study we evaluated the diagnostic performance of a new Dual-source MSCT (DSCT) that offers a temporal resolution of 83 msec. We included 40 consecutive patients (29 male, age 57+-5 years) who were referred to our institute for invasvie coronary angiography (CA) due to atypical chestpain and/or nonconclusive tests for ischemia. In these patients a DSCT-angiography (DSCTA) was performed 1 day prior to the catheterisation procedure on a Siemens Definition Scanner using a standardized protocol (collimation: 64x 0.4, 80 cc contrast agent iv at 5 cc/sec, scan duration 8 –9 sec). The diagnostic accuracy to detect coronary stenosis > 50% was compared against quantitative CA on a segmental basis. Further we determined the clinical value of DSCTA to predict or to exclude the need for revascularisation on a patient basis with the clinical decision made after CA serving as the goldstandard. DSCTA could be performed in all included patients. 17 patients were scanned at heart rates > 75 bpm. In 2 of these patients significant motionartifacts made an assessment impossible. In the remaining 38 patients 16 coronary stenosis > 50% were found on QCA and 15 were correctly identified by DSCTA (Sensitivity 94%). In 547 of 554 segments stenoses were correctly ruled out (Specificity 98%). On a patient basis DSCTA predicted the need for a revascularisation procedure in 8/8 patients and correctly excluded significant disease in 26 of 30 patients. In 4 patients diesease severity was significantly overestimated. Negative and positive predictive values were 100% and 67% respectively. DSCA is a robust technique that allows to detect coronary stenoses with high diagnostic accuracy, even in patients with high heart rates. In a patient selection with a low prevalence of coronary stenoses (21%) those patients requiring coronary revascularisation are detected reliably. Due to a tendency to overestimate stenoses however the positive predictive value is only moderate. This may be of critical importance if the test is used in populations with low to intermediate pretest likelyhood.