Table 4.

Pitfalls in the detection of acute gastrointestinal bleeding with CTA/DECTA.

FALSE NEGATIVE
Pitfall	Prevention Strategy
Fluid-filled dilated bowel	No positive or negative contrast media administration (Figure 19)
Low flow rate of contrast media administration	Rigorous CTA/DECTA examination technique; post-processing reconstructions (Figure 11 and Figure 14)
Low-flow bleeding or reduced cardiac function/hypovolaemic or septic shock etc.	CTA/DECTA late venous phase; post-processing reconstruction (Figure 4 and Figure 9)
FALSE POSITIVE
Pitfall	Prevention Strategy
Suture material, clips, foreign bodies	Unenhanced CTA scan; virtual unenhanced DECTA reconstruction; DECTA iodine map (Figure 2, Figure 7, Figure 8, Figure 16 and Figure 19)
Retained contrast media within the lumen after previous contrast media administration	Unenhanced CTA scan; virtual unenhanced DECTA reconstruction (Figure 19)
Cone-beam artefacts	Rigorous CTA/DECTA examination technique; post-processing reconstructions (Figure 19)