A structured approach to the interpretation and reporting of ventilation/perfusion scans

The aim of this study was to develop a structured approach to the reporting and in particular the clinical interpretation of ventilation/perfusion (V/Q) scan results. An initial audit indicated that there were significant variations in the clinical management of patients particularly after a non-diagnostic V/Q scan report. There were also differences in the approaches used to interpret the scan itself. In an attempt to improve this, a set of interpretation guidelines was produced based on the revised PIOPED data. To combat the problems with clinical interpretation, a standard method for assessing the pre-test clinical probability of pulmonary embolism was established. This clinical risk was then combined with the V/Q scan result to give an overall probability for the presence of pulmonary embolism. The more precise risk stratification which resulted allowed explicit clinical advice on patient management to be incorporated into the final report. A second audit was performed with the revised methodology in place. The level of inter-observer variability for scan reporting decreased from 30% to 12%. The prior assessment of clinical risk and the standardized method of combining this with the scan result led to an improvement in patient management. This was particularly true for the non-diagnostic group, in whom additional investigations were more appropriately used. A structured approach which allows the pre-test probability of pulmonary embolism to be combined in an explicit fashion with the V/Q scan result can provide a more precise risk stratification allowing appropriate recommendations to be made. Such an approach can result in improved patient management.