The role of ventilation/perfusion scintigraphy in distinguishing acute from chronic pulmonary embolism.

BACKGROUND

In this study, we examined the potential role of V/Q scintigraphy in distinguishing acute PE (APE) from chronic PE (CPE).

MATERIALS AND METHODS

From 2020 to 2023, 36 patients diagnosed with APE and 24 patients diagnosed with CPE were included in the study. Location (segmental, subsegmental, lobar), number and appearance (wedge/patch) of mismatch perfusion defects on V/Q scintigraphy were recorded, and data were compared between the two groups.

RESULTS

The number of mismatch segmental defects on V/Q scintigraphy was higher in the APE group (p = 0.042). The number of wedge-shaped defects was higher in the APE group (p = 0.003), while patchy defects were more common in the CPE group (p < 0.001). A negative correlation (p = 0.002) was observed between CPE and the number of wedges, whereas a positive correlation (p < 0.001) was found between CPE and the number of patches. Pulse oxygen saturation negatively correlated with the number of patches (p = 0.012). A negative correlation also existed between the number of mismatch segmental defects and CPE (p = 0.041). APE was indicated when the number of wedges was ≥1.5 (75% sensitivity,62% specificity, p = 0.03), while CPE was indicated when the number of patches was ≥0.5 (88% sensitivity, 61% specificity, p < 0.001). Patchy defects were found to be an independent risk factor for CPE (p = 0.008, OR: 2.1, 95% CI: 1.2-3.7).

CONCLUSION

Patchy defects serve as an independent risk factor for CPE and correlate with the severity of hypoxemia.