Clinical utilization of the non-diagnostic lung scintigram.

By virtue of the poor specificity of ventilation perfusion lung scintigraphy, a significant number of examinations for suspected pulmonary embolism (PE) result in a report which is neither normal nor high probability. These are unhelpful in establishing a firm clinical diagnosis. Patients with an indeterminate report should therefore undergo further investigation to establish the diagnosis particularly when treatment with anticoagulants is proposed. All lung scintigram reports issued over a 2-year period were reviewed and 102 indeterminate lung scintigram reports were identified. The case notes of 94 of these patients were examined and details of further investigation and management recorded. Fifty-one patients (55%) had no further radiological investigations and 19 (37%) of these were unequivocally categorized as having had pulmonary embolism by the referring clinician. Eighteen of these were treated with anticoagulation therapy. When patients proceeded to further radiological investigation then the result usually influenced the final clinical diagnosis. Clinicians frequently treat an intermediate report as the end point in investigation of suspected PE and consequently some patients may receive suboptimal management. By implementing a hospital wide policy of further investigation of non-diagnostic lung scintigrams, using a standard protocol, patient management could be improved.