The role of gallium-67 scintigraphy in diagnosing sources of fever in ventilated patients

Objective: To evaluate the diagnostic value of gallium-67 scintigraphy in febrile ventilated patients by correlating the findings of ⁶⁷Ga scintigraphy to sources of fever and pulmonary density, as determined by a comprehensive protocolized diagnostic evaluation. Design: Prospective observational study. Patients: Thirty-two intubated patients on mechanical ventilation for ≥ 3 days with fiver (≥ 38.3°C) and a new or progressive density on chest radiograph. Twenty patients (21 tests) had adult respiratory distress syndrome (ARDS). Intervention: Diagnostic evaluation for fever included bronchoscopy with protected specimen brushing and (protected) bronchoalveolar lavage (BAL); computed tomography (CT) of sinuses; cultures of blood, urine, and central lines; and CT of the abdomen in high-risk patients. Measurements and results: Uptake of ⁶⁷Ga was reported as either focal or diffuse pulmonary uptake and extrapulmonary uptake. The combined causes of fever were pneumonia (9), fibroproliferation of late ARDS (7), abdominal process (4), sinusitis (4), urinary tract infection (3), and others (6). Causes of the pulmonary densities were pneumonia (9), ARDS (13), atelectasis (7), congestive heart failure (3), and empyema (1). Marked and diffuse pulmonary uptake was found only in patients with ARDS; however, it was not useful in discriminating those patients with pulmonary fibroproliferation as the sole cause of fever (p = 0.167) from those with infection. ⁶⁷Ga scintigraphy was inadequate for detecting pneumonia but valuable in identifying extrapulmonary sites of infection in patients with ARDS (p = 0.021). Conclusions: ⁶⁷Ga scintigraphy should be considered only as an adjunct diagnostic test in the febrile, ventilated patient who has no obvious source of fever, despite a negative evaluation that includes testing for pneumonia, sinusitis, and urinary tract infection, conditions that are rarely detected by ⁶⁷Ga scintigraphy.