Paddlewheel multi-slice helical computed tomography reformation in the detection of pulmonary embolism. An initial experience

OBJECTIVE: To assess the value of paddlewheel multi-slice helical CT techniques in the detection of pulmonary embolism (PE).

METHODS: A prospective study was conducted from December 2011 to February 2013 at the Radiology Department, Dallah Hospital, Riyadh, Kingdom of Saudi Arabia. The CT scans of 71 patients presented for CT pulmonary angiography were selected and interpreted by 2 radiologists using reformatted paddlewheel technique besides coronal multiplanar volume reconstruction (MPVR). Paddlewheel reconstruction was carried out using inbuilt software on sagittal and axial images, setting 5 and 2 mm slab thickness with 5 and 2 degree angle rotation. Reference standard was overall interpretation of coronal MPVR and paddlewheel reformatted images by both radiologists.

RESULTS: In 71 patients (44 were females and 27 were male) with suspected PE, 43 were found to be positive, and 28 were found to be negative. The youngest patient was 15 years old, and the oldest was 99 years of age. Paddlewheel reformatted images display significantly high sensitivity and specificity in eliciting total number of pulmonary emboli compared to coronal MPVR by detecting 51 additional emboli. Decreasing slab thickness and rotation angle enhanced sensitivity of paddlewheel reformatted images by detecting another 11 emboli.

CONCLUSION: The paddlewheel CT angiography technique with fine slice thickness and less rotational angle enhances PE imaging.