Chest, Vol 104, 1468-1471, Copyright © 1993 by American College of Chest Physicians

ARTICLES

Mismatched vascular defects. An easy alternative to mismatched segmental equivalent defects for the interpretation of ventilation/perfusion lung scans in pulmonary embolism

PD Stein, JW Henry and A Gottschalk
Henry Ford Heart and Vascular Institute, Detroit.

The purpose of this investigation was to test the hypothesis that ventilation/perfusion (V/Q) lung scans in patients with suspected acute pulmonary embolism (PE) can be evaluated on the basis of the total number of mismatched vascular defects, irrespective of whether such defects are moderate or large size segmental defects. Lung scan data from the national collaborative study of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) were assessed in 383 patients with acute PE and 681 patients in whom suspected PE was excluded. The predictive value of the cumulative number of mismatched moderate size segmental defects (irrespective of the number of mismatched large segmental defects) was nearly the same as that of mismatched large segmental defects (irrespective of the number of mismatched moderate size segmental defects). This suggests that the diagnostic value of mismatched moderate size segmental defects is the same as mismatched large segmental defects. Lung scans evaluated on the basis of the number of mismatched vascular defects (moderate and/or large segmental defects) were compared with V/Q scans evaluated on the basis of the number of mismatched segmental equivalents. The maximum likelihood estimates of the areas under the receiver operating characteristic (ROC) curves for the number of mismatched vascular defects and for mismatched segmental equivalents were similar (0.8512 vs 0.8530) (NS). Stratification according to the presence or absence of prior cardiopulmonary disease permitted a more accurate assessment of both clinical groups. Evaluation of V/Q scans by vascular defects and by segmental equivalents showed similar areas under the ROC curves. In conclusion, the number of mismatched vascular defects is as powerful for the assessment of V/Q scans as the number of mismatched segmental equivalents. The number of mismatched vascular defects, however, is easier to interpret, and permits a more objective evaluation.

This article has been cited by other articles:

				A. Daftary, M. Gregory, A. Daftary, J. P. Seibyl, and S. Saluja Chest Radiograph as a Triage Tool in the Imaging-Based Diagnosis of Pulmonary Embolism Am. J. Roentgenol., July 1, 2005; 185(1): 132 - 134. [Abstract] [Full Text] [PDF]

				P. D. Stein, R. D. Hull, W. A. Ghali, K. C. Patel, R. E. Olson, F. A. Meyers, and N. K. Kalra Tracking the Uptake of Evidence: Two Decades of Hospital Practice Trends for Diagnosing Deep Vein Thrombosis and Pulmonary Embolism Arch Intern Med, May 26, 2003; 163(10): 1213 - 1219. [Abstract] [Full Text] [PDF]

				E. Itti, S. Nguyen, F. Robin, S. Desarnaud, J. Rosso, A. Harf, and M. Meignan Distribution of Ventilation/Perfusion Ratios in Pulmonary Embolism: An Adjunct to the Interpretation of Ventilation/Perfusion Lung Scans J. Nucl. Med., December 1, 2002; 43(12): 1596 - 1602. [Abstract] [Full Text] [PDF]

				M. A. Meignan Lung Ventilation/Perfusion SPECT: The Right Technique for Hard Times J. Nucl. Med., May 1, 2002; 43(5): 648 - 651. [Full Text] [PDF]

				T. Fennerty Fortnightly review : the diagnosis of pulmonary embolism BMJ, February 8, 1997; 314(7078): 425 - 425. [Full Text]