ABSTRACT
BACKGROUND: Direct comparison of different image reconstruction parameters to detect pulmonary embolism (PE) using 64-slice multidetector-row computed tomography (MDCT) is absent and the most accurate image reconstruction parameters have not yet been proven. PURPOSE: To compare different image reconstruction parameters for detecting PE using 64-slice MDCT in patients suspected of having an acute PE. MATERIAL AND METHODS: Forty patients who underwent pulmonary CT angiography with 64-slice MDCT for a suspected PE were included. Different image reconstruction parameters were used for each patient: axial and coronal images with slice thicknesses of 0.625 mm, 1.3 mm, and 2.5 mm and axial maximum intensity projection (MIP) images with slab thicknesses of 1.3 mm, 2.5 mm, and 5 mm. Four experienced radiologists reviewed the images. The diagnosis of a PE was based on consensus review of axial 0.625 mm slice thickness images by two chest radiologists with allowing multiplanar reconstruction. Accuracy and reproducibility (kappa value) were evaluated. RESULTS: In 15 of 40 patients, a PE was diagnosed. For detecting lobar PEs, axial images with a slice thickness of 1.25 mm and all coronal re-formatted images showed comparable results to axial images with a slice thickness of 0.625 mm. For detecting segmental PEs, axial images with a slice thickness of 1.25 mm and coronal images with a slice thickness of 0.625 mm re-formatted images showed comparable results to axial images of a slice thickness of 0.625 mm. For detecting subsegmental PEs, axial images with a slice thickness of 0.625 mm showed the highest sensitivity. Better reproducibility was obtained when the thinner slice thickness reconstructions were in axial and coronal images. However, reproducibility of MIP images with slab thicknesses of 2.5 mm and 5 mm was similar for detecting segmental and subsegmental PEs. CONCLUSION: Thin-slice reconstruction of less than 1 mm is mandatory for visualization of PE at the subsegmental level.
