High density thrombi of pulmonary embolism on precontrast CT scan: Is it dangerous? Poster No.: C-1753 Congress: ECR 2013 Type: Authors: Keywords: DOI: Scientific Exhibit B. Y. Lee, H. R. KIM, J. I. Jung, K. S. Beck; Seoul/KR Cardiovascular system, Pulmonary vessels, Cardiac, CT, Diagnostic procedure, Embolism / Thrombosis 10.1594/ecr2013/C-1753 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 7
Purpose In the evaluation of pulmonary embolism, contrast enhanced CT is necessary. But the use of contrast material is contraindicated in many patients due to renal function or other problems. Sometimes high density thrombi are seen in pre-contrast CT scan, but its clinical significance has not been studies. The purpose of this study is to evaluate the significance of occasionally detected high density thrombi in pulmonary arteries on nonenhanced CT scan. Methods and Materials We retrospectively reviewed 70 consecutive pulmonary embolism (PE) patients with preand post-contrast enhanced CT scans. We used 4, 16, 64 MDCT (GE, USA). Rotation time was 0.6sec. Slice thickness was 2.5mm. kvp is 120mA and mas was auto-regulated (100-330). Contrast material was Ultravist (Bayer Schering) 130cc with injection rate of 1.3mL/sec. We divided PE into high and iso-density thrombi groups and analyzed the following criteria: 1.Age, sex, d-dimer 2.Embolic burden score on pre- and post-contrast enhanced scan, ventricular septal bowing, RV/LV diameter ratio, location of thrombi, deep vein thrombosis. Embolic burden score is calculated with number of involved segments. If there is complete obstruction, the number is doubled. Ventricular septal bowing is defined as presence or absence of septal bowing towards left ventricle. RV diameter is measured at tricuspid valve and LV diameter measured at mitral valve level on axial scan. Location of thrombi is classified as main, lobar, and segmental pulmonary arteries. Statistical analysis was done using independent sample T test. Results Page 2 of 7
High density thrombi were seen in 27% (19 patients, 7 males and 12 females). Iso density pulmonary embolism were seen in 51 patients (24 males and 27 females). Mean age of the patients was similar (high density 67.5±8.8, iso-density 68.8±14.5). D-dimer level was higher in high density group, but statistically insignificant. High density group showed more central and large artery involvement, but this was also statistically insignificant. Embolic burden score and ventricular septal bowing were significantly more severe in high density group. Results are summarized below. Group 1 (n=51) Group 2 (n=19) P value sex 24male 7 male 0.451 Age 68.8±14.5 67.5±8.8 0.725 D-dimer (ug/dl) 6.4±6.2 7.5±4.6 0.490 Location (main=1, lobar =2, segmental=3) Embolic burden score on pre-ce Embolic burden score on post-ce Ventricular bowing septal 2.04±0.89 1.68±0.82 0.136 0.86±3.3 8.84±6.2 <0.001 7.4±5.9 13.3±6.8 0.001 3 cases 9 cases <0.001 RV diameter (mm) 44.3±8.2 45.2±8.3 0.674 LV diameter (mm) 40.8±6.6 38.2±7.3 0.172 DVT 17/35 8/17 0.92 Images for this section: Page 3 of 7
Fig. 1: Pulmonary embolism in main pulmonary artery. High density pulmonary thrombi are well delineated on pre-contrast and post-contrast CT scan (arrows) Page 4 of 7
Fig. 2: Ventricular septal bowing. Interventricular septum is deviated to left side (arrow) and distended right ventricle is well delineated. Page 5 of 7
Fig. 3: Pulmonary embolism on segmental artery. High density thrombi are well demonstrated on pre- and post- contrast CT (arrows) Page 6 of 7
Conclusion High density thrombi in pulmonary arteries are frequently detected on pre-contrast CT scans. They are correlated with ventricular septal bowing and high embolic burden score, which corresponds to more dangerous cases of pulmonary embolism. Radiologists should have in mind and check the possibility of thrombi on pre-contrast CT scans. References 1. Pulmonary embolism: Prognostic CT findings. Araoz PA et al. Radiology 2007;242;889-897. 2. Severe pulmonary embolism: pulmoanry artery clot load scores and cardiovascular parameters as predictors of mortality. Ghaye B, et al. Radiology 2006;239;884-891. 3. Right ventricular dysfunction and pulmonary obstruction indes at helical CT: prediction of clinical outcome during 3-month follow up in patients with acute pulmonary embolism. van der Meer et al. Radiology 2005;235;798-803. 4. Right ventricular enlargment on chest computed tomography: A predictor of early death in acute pulmonary embolism. Schoepf UJ, et al. Circulation 2004;110;3276-3280. 5. CT diagnosis of chronic pulmonary thromboembolism. Castaner E, et al. Radiographics 2009;29;31-53. 6. 64-MDCT pulmonary angiography and CT venography in the diagnosis of thromboembolic disease. Nazaroglu H, et al. AJR 2009;192;654-661. Personal Information Page 7 of 7