To Study The Value Of 64-Slice Spiral Computed Tomography Angiography In The Diagnosis Of Coronary Artery In-stent Restenosis

Background:In recent years, coronary artery disease has been increasingly treated by coronary stent placement. While the clinical incidence of in-stent restenosis after coronary stenting is one of the significant complications.Conventional invasive coronary angiography is widely used in clinical practice to detect in-stent restenosis as it allows direct visualization of the vessel lumen. However, coronary angiography is an invasive procedure associated with complications.Currently multislice computed tomography (MSCT) angiography has been evaluated for assessment of coronary stent patency or restenosis. The recently developed 64-slice spiral CT scanners allow for more accurate stent visualization and characterization due to increased spatial and temporal resolution. As 64-slice CT is becoming widely available in clinical practice, and also is increasingly used for assessment of coronary stents, therefore, it is necessary to know whether the 64-slice CT angiography has reached the diagnostic accuracy as that of coronary angiography for the detection of in-stent restenosis.Objective:To evaluate the diagnostic value of 64-slice CT angiography for the detection of coronary in-stent restenosis in patients treated with coronary stents when compared to conventional coronary angiography.Materials and Methods:Thirty-five patients who had been performed coronary stenting were included in the study. All the patients were examined by 64-slice SCTA and CAG for evaluating ISR after coronary stenting. VR,MPR,CPR,MIP reconstruction with enhanced scan images were made in every case. All segments within stent were assessed by two observers in consensus, and were graded according to the following scheme:patient stent, in-stent intimal hyperplasia (lumen reduction <50%), in-stent restenosis (≥50%). The results of CAG were taken as the golden standard to evaluate the sensitivity,specificity,misdiagnosis rate,missed diagnosis rate,Youden index of 64-SCTA in diagnosis of ISR after PCI.Results:68 stented lesion(91%) were classified as evaluable in 64-MSCTA,18 in-stent restenosis lesions were found by 64-MSCTA, while 20 lesions were found by CAG. 64-MSCTA correctly diagnosed 16, misdiagnosed 2, and missed 4. The sensitivity,specificity,misdiagnosis rate,missed diagnosis rate,Youden index were 80%,95.83%,4.17%,20%,0.76, respectively. There is no significant difference between 64-MSCTA and CAG for the detection of coronary in-stent restenosis.Conclusion:Our study showed that 64-slice CT angiography has relatively high diagnostic accuracy for the detection of coronary in-stent restenosis when compared to conventional coronary angiography. With increased spatial and temporal resolution achieved with 64-slice CT and aid of appropriate edge-enhancing convolution kernel, 64-slice CT angiography could be used as a reliable alternative to conventional coronary angiography for the assessment of coronary in-stent restenosis.