Relationship Of reconstruction slice thickness and interval with accuray of computer-aided detection system:detection of pulmonary nodules by 64-slice helical CT
AIM:To evaluate the effect of various reconstruction slice thicknesses and reconstruction intervals on diagnostic accuracy of pulmonary nodules with the computer-aided detection ( CAD) system of LungCare software. METHODS: Forty-eight patients with pulmonary nodules,five sets of CT images were reconstructed in each patient by selecting five reconstruction slice thickness and interval combinations respectively: 0.75/0.70 mm,1/1 mm,3/3 mm,5/1 mm,5/5 mm. The performance of the CAD system using different reconstruction combinations were compared with receiver operating characteristic curves analysis. RESULTS:152 pulmonary nodules were detected according to the reference standard. The Az value was significant larger in 0.75 mm or 1 mm reconstruction section thickness ( Az = 0. 86 and 0.84 for 0. 75 ram and 1 mm,respectively) than that of 5.0 mm or 3.0 mm (Az = 0.48,0.53 and 0.40 for 3/3 mm,5/1 mm,5/5 mm,respectively,P < 0. 05). In the case of the overlapping reconstruction (5/1 mm),although the Az value of CAD (Az =0.53) was larger than that of 5 mm section interval (Az =0.40),there is no significant difference,but significantly smaller than that of 1 mm slice thickness ( P < 0.05 ). Sensitivity of CAD for 1 mm reconstruction section thickness(84% )was the largest among the five sets,while the number of false-positive findings per patient for 0. 75 mm thickness (0.56) was the smallest. With the increase of slice thickness,the average diameter of the nodule detected by CAD was increased,but the small nodule was decreased significantly. CONCLUSION :0. 75 mm or 1 mm reconstruction section thickness outperforms that of 3.0 mm or 5.0 mm using CAD system in detection of pulmonary nodules. Overlap reconstruction enhances the accuracy of CAD but its role is very limited.
NETL
NSTL
万方数据
维普
