The study is done to rule out a hepatic mass
| Problem | The clinical indication can vary from being part of a staging CT scan (i.e. stage colon cancer), to evaluating a patient with an incidental liver lesion seen on a non-contrast CT or the chest and or abdomen to a patient with elevated LFTs. The clinical question will often define the protocol and whether it is single or dual phase acquisition. The role of non-contrast scans or delayed scans (3-5 minutes post injection) has been debated and are rarely used. |
| Protocol | Typically contrast injection protocols are 100-120 cc of contrast injected at 4-5 cc/sec. Water is routinely used to distend the stomach and duodenum. |
| Pearls | - The selection of the correct imaging protocol is mandatory if we are to optimize detection and characterization of hepatic masses.
- If the study is done as part of an oncology staging protocol the use of single vs dual phase acquisition will typically be dependent on the tumor type. For colon cancer it is typically venous phase only and the a neuroendocrine tumor it will be arterial and venous phase imaging
- If the study is done in a patient with elevated LFTs or in a patient with cirrhosis dual phase imaging will be required. Hepatomas are usually best seen on arterial phase imaging. In suspected hepatoma some sides suggest a delayed phase acquisition as well at 5 minutes post injection
- For evaluation of a known mass (i.e. incidental finding on non contrast CT) dual phase imaging is ideal to determine its etiology (i.e. FNH, Hepatic Adenoma, Hemangioma, Hepatoma, etc.). In select cases delayed phase images will also be helpful.
- Typically contrast injection protocols are 100-120 cc of contrast injected at 4-5 cc/sec. Water is routinely used to distend the stomach and duodenum.
- MPR and 3D mapping ( VRT and MIP) may be very helpful in staging liver masses and determining their etiology. Cinematic rendering is now being used more frequently.
- In cases the liver is cirrhotic even the smallest enhancing liver lesion should be suspicious for hepatoma
- On arterial and venous phase imaging vascular maps should be analyzed and generated for processes including AV shunting and portal vein thrombosis.
|
