The Role of Advanced Post-processing Techniques in Computed Tomography Pulmonary Angiography for the Accurate Diagnosis of Pulmonary Thromboembolism: A Retrospective Study.

Background Computed tomography pulmonary angiography (CTPA) is the standard diagnostic tool for evaluating patients with suspected pulmonary thromboembolism (PTE) in many institutions. This condition, whether acute or chronic, results in both partial and complete intraluminal filling defects, which exhibit sharp interfaces with intravascular contrast material. Acute PTE that leads to complete arterial occlusion may cause the affected artery to appear enlarged. Chronic PTE often manifests as complete occlusive disease in vessels that are smaller than the adjacent patent vessels. CT imaging with iodinated contrast medium is crucial for many CT applications, including vascular CT angiography and CTPA. A comprehensive review of a case necessitates an integrated approach known as volume visualization, wherein the entire case is treated as a volume of information to be thoroughly reviewed. Advanced post-processing 3D CT techniques, such as maximum intensity projection (MIP), volume rendering (VR), and minimum intensity projection (MinIP) images, are essential for the detailed detection and assessment of the pulmonary vasculature. Materials and methods In this retrospective study, data from 50 patients with suspected PTE were analyzed over a six-month period from March 15 to August 30, 2023, at Saveetha Medical College and Hospital. Patients were selected based on previously recorded clinical symptoms and elevated D-dimer levels. CTPA images, acquired using multi-detector CT imaging with iodinated contrast, were reviewed. Various post-processing techniques were employed, including multiplanar reconstruction (MPR), MIP, MinIP, and VR. The aim of this study was to evaluate the effectiveness of CTPA combined with advanced post-processing techniques in improving early detection, reducing diagnostic time, and increasing accuracy through the detailed visualization of the pulmonary arterial vasculature. Results The study included patients aged from 10 years to 70 years, with the highest prevalence of PTE in the 21-35-year age group (46%). Males constituted 56% of the cases. CTPA with advanced post-processing techniques revealed filling defects in 90% of patients, confirming PTE. MPR, MIP, MinIP, and VR effectively highlighted anatomical structures and thrombi, enhancing diagnostic accuracy. These techniques demonstrated high accuracy in identifying PTE, emphasizing their critical role in the early diagnosis and management of thromboembolic events. Conclusion The findings of the study revealed a relatively high incidence of PTE especially in the 21-35-year age group with a slight male predominance. The significant majority of the patients (90%) had filling defects on their CTPA scan. CTPA, in conjunction with the use of post-processing techniques, the localization of thromboembolism sites, as well as the measurement of thrombus width and length, and the calculation of the percentage of blockage were achieved more easily. This facilitated accurate diagnosis, leading to improved patient outcomes.