Incidental detection of pulmonary emboli on routine MDCT of the chest.

OBJECTIVE The objectives of our study were to assess the prevalence of pulmonary embolism incidentally detected on routine MDCT of the chest and to determine whether the use of wide window settings can improve detection of unsuspected pulmonary embolism. MATERIALS AND METHODS A retrospective review of routine contrast-enhanced MDCT scans of the chest obtained in 589 patients was undertaken. CT angiograms obtained for suspected pulmonary embolism or thoracic aorta disease were not considered. Image evaluation was performed on a dedicated workstation during two separate review sessions using different window settings: standard, with a width of 400 H and level of 40 H; and wide, with a width of 600 H and level of 100-150 H. The quality of vascular enhancement was recorded. RESULTS Eight examinations were excluded because of poor quality. Unsuspected pulmonary embolism was present in 20 (3.4%) of 581 patients with an inpatient prevalence of 4.0% (19/474) and outpatient prevalence of 0.9% (1/107). Fourteen patients (70.0%) with unsuspected pulmonary embolism had cancer. The proximal extent of pulmonary embolism involved the main pulmonary artery in five patients, a lobar artery in five, and a segmental artery in 10; isolated subsegmental thrombi were never found. The use of wide window settings allowed detection of pulmonary embolism in two more patients than did the standard settings. CONCLUSION Unsuspected pulmonary embolism can be found in a significant number of patients undergoing a routine MDCT study of the chest, with a higher prevalence among inpatients with malignancy. The use of wide window settings is recommended when interpreting routine CT scans of the chest to improve detection of unsuspected pulmonary embolism.

[1]  H. Liebman,et al.  Low-molecular-weight heparins in the prevention and management of malignancy-related venous thromboembolism , 2006 .

[2]  L. Broemeling,et al.  Incidental pulmonary emboli in oncology patients: prevalence, CT evaluation, and natural history. , 2006, Radiology.

[3]  P. Wells.  Advances in the Diagnosis of Venous Thromboembolism , 2006, Journal of Thrombosis and Thrombolysis.

[4]  M. Landay.  Clinical evidence of recurrent venous thromboembolism in patients who did not receive anticoagulant therapy. , 2005, AJR. American journal of roentgenology.

[5]  Y. Tsushima,et al.  Portal perfusion measurement on dynamic CT in patients with liver cirrhosis. , 2005, AJR. American journal of roentgenology.

[6]  Smita Patel,et al.  Pulmonary embolism: optimization of small pulmonary artery visualization at multi-detector row CT. , 2003, Radiology.

[7]  Mathias Prokop,et al.  General principles of MDCT. , 2003, European journal of radiology.

[8]  Alexander Crispin,et al.  Subsegmental pulmonary emboli: improved detection with thin-collimation multi-detector row spiral CT. , 2002, Radiology.

[9]  P. Boiselle,et al.  Multi-detector row spiral CT pulmonary angiography: comparison with single-detector row spiral CT. , 2001, Radiology.

[10]  M. Lewis,et al.  Multislice CT: opportunities and challenges. , 2001, The British journal of radiology.

[11]  B Ghaye,et al.  Peripheral pulmonary arteries: how far in the lung does multi-detector row spiral CT allow analysis? , 2001, Radiology.

[12]  A. Romero,et al.  Systematic study of occult pulmonary thromboembolism in patients with deep venous thrombosis. , 2001, Journal of vascular surgery.

[13]  T. Smith.  Pulmonary embolism: what's wrong with this diagnosis? , 2000, AJR. American journal of roentgenology.

[14]  G. Simonneau,et al.  Systematic lung scans reveal a high frequency of silent pulmonary embolism in patients with proximal deep venous thrombosis. , 2000, Archives of internal medicine.

[15]  G D Rubin,et al.  Unsuspected pulmonary embolism: prospective detection on routine helical CT scans. , 1998, Radiology.

[16]  G. Wang,et al.  Depiction of pulmonary emboli with spiral CT: optimization of display window settings in a porcine model. , 1997, Radiology.

[17]  P. Spirn,et al.  Incidental pulmonary emboli detected at helical CT: effect on patient care. , 1996, Radiology.

[18]  J. W. Henry,et al.  Prevalence of acute pulmonary embolism among patients in a general hospital and at autopsy. , 1995, Chest.

[19]  H L Kundel,et al.  Mechanism of satisfaction of search: eye position recordings in the reading of chest radiographs. , 1995, Radiology.

[20]  S. Husted,et al.  Silent pulmonary embolism in patients with deep venous thrombosis. Incidence and fate in a randomized, controlled trial of anticoagulation versus no anticoagulation , 1994, Journal of internal medicine.

[21]  K. Moser,et al.  Frequent asymptomatic pulmonary embolism in patients with deep venous thrombosis. , 1994, JAMA.

[22]  J. Bogaert,et al.  Detection of unsuspected central pulmonary embolism with conventional contrast-enhanced CT. , 1993, Radiology.

[23]  P. Traughber,et al.  MR arthrography is not proven to be preferred baseline MRI examination. , 2006, AJR. American journal of roentgenology.

[24]  R. Fitzgerald.  Performance-based assessment of radiology faculty. , 2006, AJR. American journal of roentgenology.