Contrast enhanced chest-MDCT in oncologic patients. Prospective evaluation of the prevalence of incidental pulmonary embolism and added value of thin reconstructions.

objectivesTo prospectively assess prevalence/characteristics of clinically unsuspected pulmonary embolism (PE) in cancer patients undergoing follow-up chest MDCT and investigate MDCT protocol.

methodsWe evaluated 1013 oncologic patients. MDCT images at 5 and 1.25 mm thickness were independently evaluated. Pulmonary artery opacification degree was assessed. Presence, level, and site of PE were reported. Type of malignancy and metastases were reported for PE-positive patients.

resultsAfter excluding 1.4% (14/1013) of examinations due to inadequate vessel opacification, 999 patients (572 male; mean age:68 ± 12 years; range:26-93 years) entered the study. Prevalence of PE was 5%. There was significant improvement in the sensitivity for both readers in the evaluation of 1.25 mm compared to 5 mm images (46-50% to 82-92%). 30% (15/51) PE were not described by the radiologist in the prospectively issued report; 53 % (27/51) of PE were segmental, 72.5% (37/51) unilateral. The right lower lobe was the most involved (59%). 27% patients had colon cancer, 18% lung cancer. Among PE-positive patients (25 male; mean age 70 ± 10 years; range:44-87 years), 25% (13/51) had lung cancer, 15% (8/51) colon cancer.

conclusionsThin reconstructions are essential for PE diagnosis, regardless of reader experience. Regarding oncologic patients, incidental PE diagnosis influences anticoagulation therapy. KEY POINTS: • CT pulmonary angiography is the gold standard for PE diagnosis. • Cancer and oncological treatments are risk factors for PE. • The prevalence of unsuspected PE was 5%. • Thin reconstructions are essential for PE diagnosis regardless of reader experience. • In oncologic patients, PE diagnosis influences anticoagulation therapy.