Table 3.

CTA protocol for overt GIB and optional CTE protocol for occult GIB or SBB.

	Overt GIB—CTA Protocol	Occult GIB or SBB—CTE Protocol
IV administration of contrast medium	80–130 mL of high-concentration iodinated contrast medium (370–400 mgI/mL)	80–130 mL of high-concentration iodinated contrast medium (370–400 mgI/mL)
Speed of administration	The highest possible flow (3.5–4 mL/s) through an 18G cannula	The highest possible flow (3.5–4 mL/s) through an 18G cannula
Normal saline	40 mL of high-flow normal saline	40 mL of high-flow normal saline
Oral administration of contrast medium	Not recommended	1350–1500 mL of fractionated neutral oral contrast agent starting about 1 h prior to the examination
Scanned area	From the diaphragm to the pubic symphysis (possible extension to the chest)	From the diaphragm to the pubic symphysis
Phases of acquisition	Multiphase CT technique: Without contrast or virtual no contrast Arterial phase (bolus tracking technique) Venous phase (70–90 s after injection) Optional late phase (5 min after injection)	Multiphase CT technique: Without contrast or virtual no contrast Late arterial phase (10 s after bolus trigger) Enteric phase (50 s after injection) Late venous phase (90 s after injection) Alternative technique: split bolus protocols may be adopted
Post-processing	2.5–3 mm axial slices for each series (optional 1 mm axial) Coronal and sagittal reconstruction of 2.5–3 mm images (50% overlap) Optional maximum intensity projection and volumetric reconstruction	2.5–3 mm axial slices for each series (optional 1 mm axial) Coronal and sagittal reconstruction of 2.5–3 mm images (50% overlap) Optional maximum intensity projection and volumetric reconstruction
DECTA post-processing	40–60 keV (i.e., virtual monoenergetic), iodine density, virtual non-contrast and standard mixed series	40–60 keV (i.e., virtual monoenergetic), iodine density, virtual non-contrast and standard mixed series