Data collection and review of PET/CT contribution
For each patient, we collected data on their demographics, medical
history, current episode of fever, laboratory tests, and imaging
studies. We examined the PET/CT results and reviewed the final diagnosis
if it was made within 3 months of discharge. Finally, we evaluated the
results of the PET/CT studies and concluded whether the test was
contributory to the final diagnosis. This was determined by two internal
medicine consultants. When controversies arose regarding the
contributory value of a test, a third physician reviewed the data, and a
decision was made based on the rule of the majority.
Tests were considered true positives and therefore contributory if they
had positive findings that were relevant to the diagnosis. Studies were
labelled as true negative if no positive hypermetabolic findings were
observed, and no clinical diagnosis was established during 3 month
follow-up. True negative tests (negative PET/CT scan, with no diagnosis
made within 3 months) were not considered contributory since excluding
diagnoses were not considered of value. Tests were called false positive
if PET/CT showed hypermetabolic findings, but these findings did not add
to the final diagnosis; or if no diagnosis was made at all within 3
months of follow-up. They were considered false negative if no
hypermetabolic findings were observed and the diagnosis was made by
other means of investigations.