Ventilation-perfusion studies in suspected pulmonary embolism.

Area of Science:

• Nuclear Medicine
• Radiology
• Cardiovascular Imaging

Background:

• Pulmonary embolism (PE) diagnosis relies on imaging modalities.
• Ventilation-perfusion (V-Q) scintigraphy is a key diagnostic tool for PE.
• Interpreting V-Q patterns requires correlation with other imaging findings.

Purpose of the Study:

• To determine the frequency of PE associated with specific V-Q scintigraphic patterns.
• To correlate V-Q imaging findings with pulmonary angiography results in suspected PE.
• To establish a classification system for PE probability based on V-Q imaging characteristics.

Main Methods:

• Retrospective analysis of 146 patients with suspected pulmonary embolism (PE).
• Review of ventilation-perfusion (V-Q) imaging and pulmonary angiography results.
• Categorization of V-Q scintigraphic patterns and comparison with diagnostic outcomes.

Main Results:

• High PE probability (92%) with ≥2 moderate or 1 large V-Q mismatch.
• Low PE frequency with small V-Q mismatches or matched V-Q/radiographic abnormalities.
• High PE probability (87%) when perfusion defects were larger than radiographic abnormalities.

Conclusions:

• V-Q scintigraphy patterns, particularly size and number of mismatches, predict PE probability.
• Comparison of perfusion defects with ventilatory and radiographic findings refines PE risk assessment.
• Patients can be stratified into low, intermediate, or high PE probability groups using V-Q imaging.