Ventilation Perfusion Scan

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Contents 1 Introduction 2 Indications 3 Clinical-significance 4 More General Terms 5 References

Introduction

• Assessment of ventilation- perfusion (VQ) mismatch.

Indications

• assessment of pulmonary embolism

Clinical-significance

• initial diagnostic modality in the evaluation of pulmonary emboli [4]
• ventilation is the absence of perfusion suggests pulmonary emboli
• two or more segmental defects on perfusion scan suggest large vessel chronic thromboembolic disease or pulmonary hypertension
• however, defects on perfusion scan are non-specific & may be seen in COPD
• pulmonary angiography is indicated to resolve equivocal findings on VQ scan.

• Sensitivity: 77%, specificity 98% [3]
• VQ scans underestimate severity of central pulmonary arterial obstruction. [2]

More General Terms

• radiography (diagnostic imaging, roentgenography)

References

1. Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
2. Smith R., Jewish Home for the Aging, Reseda CA, 2001, unpublished
3. Sostman HD et al, Acute pulmonary embolism: Sensitivity and specificity of ventilation-perfusion scintigraphy in PIOPED II study. Radiology 2008, 246:941 PMID: [1]
4. Salaun P-Y et al. Noninvasive diagnosis of pulmonary embolism. Chest 2011 Jun; 139:1294 PMID: [2]

ventilation-perfusion (VQ) scan