Bohyun Kim MD, Presenter: Nothing to Disclose

Joon Beom Seo MD, PhD, Abstract Co-Author: Speaker, Siemens AG

Eun Jin Chae MD, PhD, Abstract Co-Author: Nothing to Disclose

Hyun Joo Lee, Abstract Co-Author: Nothing to Disclose

Hye Jeon Hwang MD, Abstract Co-Author: Nothing to Disclose

Chae Hun Lim, Abstract Co-Author: Nothing to Disclose

To identify nonembolic causes of perfusion defects on contrast enhanced dual-energy pulmonary CT angiography (DECTPA) and to analyze the defect pattern for each cause.

152 consecutive patients underwent DECTPA for clinical suspicion of embolism (PE). Exclusion criteria of patients include overt PE on CT, presence of DVT, history of previous PE and poor image quality. Consequently, 85 patients with 510 lobes were included in the study (M:F=42:43; mean age, 60.64 yr). DECTPA scanning (Somatom Definition, Siemens) was performed at 140 kV and 80 kV. Color-coded perfusion images were obtained with a Lung PBV application of the workstation software (Syngo Dual Energy). The presence, incidence and pattern of perfusion defects (PD) in each lobe were evaluated and their causes were assessed on matched conventional images by two readers in consensus.

Out of 510 lobes, 37 lobes (7.3%) demonstrated artifacts accounted for more than 30% of the each lobe area. With the right middle lobes being the most common sites (27%), these lobes were waived from further evaluation. Additional 21 lobes (4.1%) were also set aside mostly because of atelectasis. PDs were seen in 114 out of 510 lobes in total (22%). Nonembolic vascular causes of PDs were as follows; extrinsic occlusion/stenosis of PA at hilum by fibrosing inflammation, 9 lobes (1.8%); congenital PA hypoplasia, 3 (0.6%); venous occlusion, 2 (0.4%) and pulmonary angiosarcoma 1 (0.2%). PD areas were matched with vascular territory in most cases. Nonvascular causes include: mosaic lung attenuation, 55 (10.8%); bronchitis, 17 (3.3%); emphysema, 13 (2.6%); bronchiectasis, 5 (1%); cellular bronchiolitis, 3 (0.6%); bronchial obstruction by mucus, 2 (0.4%) and bronchopneumonia, 1 (0.2%). PDs was geographic and mismatched with anatomic extent in cases with bronchitis, bronchiectasis and bronchopneumonia, whereas PDs by cellular bronchiolitis, mosaic attenuation and emphysema were well matched with anatomic extent. PDs were shown in four normal lobes without any visible pathology (0.8%).

PDs without PE on DECTPA is not uncommon. Various nonembolic vascular and nonvascular diseases can develop PDs in different pattern.

Perfusion status on DECTPA should be assessed with conventional images because nonembolic diseases develop PDs also. DECTPA may be used in assessment of perfusion status in nonembolic diseases.

Kim, B, Seo, J, Chae, E, Lee, H, Hwang, H, Lim, C, Nonembolic Causes of Perfusion Defect on Contrast-enhanced Dual-Energy CT: Review of 85 Consecutive Cases.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9007869.html