Table 1. Summary of imaging techniques for the evaluation of portal system and collaterals.
| Modality | Indication | Advantage | Disadvantage |
|---|---|---|---|
| US (B-mode/Doppler) | First line approach | Simple and non-invasive | Dependent on operator and patient condition |
| Detection of blood flow | Real-time observation | Poor detection of blood flow with slow velocity | |
| Detection of flow direction | |||
| Velocity measurement | |||
| CT/MRI | First/second line approach | Less-invasive | Possible adverse event with contrast material |
| Detection of blood flow | High reproducibility and objectivity | ||
| Arteriography | Detailed examination | Indirect enhancement of portal system (via spleen/intestine) | Possible adverse event with contrast material |
| Therapeutic support (partial splenic embolism) | Invasiveness (moderate) | ||
| No measurement of portal pressure | |||
| Venography | Detailed examination | Indirect/retrograde enhancement of portal system | Possible adverse event with contrast material |
| Therapeutic support (BRTO) | Possible HVPG measurement | Invasiveness (moderate) | |
| PTP | Therapeutic support (PTO) | Direct enhancement of portal system | Possible adverse event with contrast material |
| Direct portal pressure measurement | Invasiveness (high) |
US, ultrasound; CT, computed tomography; MRI, magnetic resonance imaging; PTP, percutaneous transhepatic portography; BRTO, balloon-occluded retrograde transvenous obliteration; HVPG, hepatic venous pressure gradient; PTO, percutaneous transhepatic obliteration.