The frequency, appearance, and significance of splenic perfusion defects in CT arterial portography.

Background: The purpose of this study was to determine the frequency, appearance, and significance of splenic perfusion defects on computed tomographic arterial portography (CTAP).
Methods: CTAP was performed with dynamic scanning at 1-cm increments on 46 consecutive patients prior to laparotomy. Two readers retrospectively reviewed these studies in consensus and recorded the number, size, and shape of focal splenic perfusion defects. These defects were later correlated with surgical findings and at least one of the following imaging modalities: delayed CT 4-6 h after CTAP, intravenously enhanced CT, sonography, or magnetic resonance imaging (MRI).
Results: Splenic perfusion defects were present in 14 of 46 CTAP studies (30%), and in seven patients these defects were multiple. Most defects were wedge-shaped and peripherally located, although several round defects simulating metastases were also present. The spleen was normal at surgery in all patients, and comparison imaging revealed only a small splenic infarct in one patient on MRI.
Conclusions: Splenic perfusion defects occur in about one-third of patients referred for CTAP, are usually wedge-shaped but may be round, and should not be interpreted as metastases without other evidence of a space-occupying mass.