Many fluid collections are the result of surgical intervention and often cannot be differentiated on ultrasound alone. Diagnostic aspiration of fluid collections is used to establish their
exact nature: this may include haematoma, lymphocoele, urinoma, biloma, pseudocysts and others.
Postoperative haematomas are normally treated conservatively and tend to resolve spontaneously.
Insertion of a drain into such a collection is at high risk of converting the collection into an abscess. Complications of ultrasound-guided biopsy
Author Year Number of biopsies Mortality rate major complication rate
Fornari et al 1989 10 800 1:5400 1:530
Nolsoe et al 1990 8000 1:2700 1:540
Smith 1991 16 400 1:3300 -