Pyrexia of Unknown Orgin (PUO) is defined as fever of 3 weeks duration with body temperature above 38.5oC on several occasions and no established diagnosis after one week of hospitalisation or two weeks of outpatient investigation. In a densely populated country like India, patients presenting with PUO is becoming a challenging task for the treating physicians. The aim of our study is to prove the efficacy of F18 FDG PET-CT as an effective diagnostic tool in evaluation and management of patients with PUO.

A total of 94 patients (51 males, 43 females) who underwent 18 FDG PET-CT as part of investigative work up of PUO were analysed prospectively during a periodof 2 years. —PET-CT imaging wasperformed after getting informed consent and 6 hours fasting. Blood sugar was checked in a peripheral vein (ideally should be around 150 mg/dl) and 5mCi of 18F Fluorodeoxy glucose was injected. —Patients weremade to rest for 40 minutes after the administration of FDG.— Oral and non-ionic intravenous contrast agents (1ml/kg body weight with...

Abnormal FDG uptake was noticed in 95% of the patients. The final cause for the same was divided as infective and non infective. 74% patients had infective causes of which 90 percent was due to tuberculosis. This included various spectrum of Tuberculosis presentation like caseating nodes, ileocaecal abscess, peritonitis etc. 10 percent were due to fungal and microbial infections. Non-infective causes included malignancies like lymphomas/haematological malignancies (80%) and bronchogenic malignancy (2%) and inflamatory conditions like vasculitis (8%), sarcoidosis (2%), inflammatory bowel disease (2%), thyroiditis (1%),...

In our study 18 FDG PET-CT had more than 90% sensitivity and 60% specificity in correlation with final tissue diagnosis and almost 100% negative predictive value in excluding occult malignancy and infective foci. The synergy of anatomic-metabolic information is very beneficial in the diagnostic work up of PET CT. In an endemic country like India F18 FDG PET-CT can be an efficient, noninvasive technique for evaluation, management and follow up of patients with PUO and in deciding the best site for biopsy. Performing PET CT...

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