Ventilation-perfusion (V/Q) lung scintigraphy: a long journey to a renewed position of prominence in diagnosing pulmonary embolism

The ventilation-perfusion (V/Q) lung scan has traveled a long, circuitous path since its introduction for the diagnosis of pulmonary embolism (PE) in the 1960s. Its initial credibility was damaged following the publication of the PIOPED study in 1990 and the emergence of computed tomographic pulmonary angiography (CTPA) in the mid-1990s. A considerable number of advances in both methodology and image interpretation have helped to restore the credibility of V/Q. There has also been considerable concern over the large radiation burden associated with CTPA. The issue of overdiagnosis and overtreatment of small PEs has also received a lot of attention. Although CTPA diagnoses more of these smaller PEs than V/Q, follow-up “outcomes” data show that they do not require treatment. The false-negative rates for both procedures are approximately 1 % and not significantly different from one another. Finally, a change from traditional probability interpretations to a simpler and similarly accurate trinary system has made V/Q scintigraphy interpretations easier to understand for the referring clinician.