Interventional radiology of the liver Flashcards
What are the current treatment options for hepatocellular carcinoma?
Transplantation
Surgical resection
- REA=ablation
- PEI = percutaneous alcohol infusion = kills tumours cells
- TACE / TAE = transcutaneous arterial chemo-embolisation / transarterial embolisation = blocking the blood supply to the tumour
Chemotherapy
Palliative = sorafenib
radiology is both involved in palliative and curative care
Which patients usually have PEI?
Reserved for those who have little other choice
small <3cm tumours
visible on US
How is PEI carried out?
Need IV sedation and opiates
US guided insertion of 21Gauge needle
5-10mls dehydrated alcohol injected at each treatment session
usually 4 injections at weekly intervals
the alcohol is tumouricidal
What are the principles of radiofrequency ablation / microwave?
Thermo-ablative technique
- percutaneous, laparoscopic or intra-operative placement of electrode into lesion
- high freq alternating current via electrodes
- cell death by temperature >60 degrees
= causes coagulation and necrosis of cells
What is involved in microwave ablation?
electromagnetic radiation, freq >900MHz
principles are similar to RFA
advantages, higher intratumoural temperatures
less heat sink from vessels
get ore of a uniform burn - burns it quicker than RFA-burn it in minutes
How are patients chosen for ablation therapy?
MDT meeting - develop treatment plan Good and recent imaging - proximity to major vessels/structures - number and segmental distribution of lesions - lesion size <3cm ideally but up to 5cm important to consider: - percutaneous/intra-operative approach - general anaesthetic - co-morbidity
What types of lesions are difficult to ablate?
lesions >5cm dome of the liver sub-capsular lesions abutting bowel lesions close to or invading into large vessels hilar lesions
What is involved in the intra-operative approach?
combined surgical and RFA
open RFA
What is the percutaneous approach used?
majority of cases
well tolerated
patient unwilling to have surgery
How is basic ablation technique carried out?
accurate imaging guided placement of probe into lesion
multiple overlapping placements to ensure good coverage of lesions with clear margins
- use contrast US, MRI, US/CT fusion
What is involved in the advanced vascular technique?
reduce heat sink effect
- hepatic vein occlusion
- portal vein occlusion
- arterial embolisation
What is involved in the advanced non-vascular technique?
safer and more accurate access
- hydro/pneumothorax: high lesions
- pneumoperitoneum: chest wall injury
- hydrodissection: displace adjacent structures
- coil placement for localisation
- cholecystostomy
What are the general complications with ablation therapy?
bleeding
direct adjacent structure injury
GA/Sedation
infection
What complications can arise from current flow in ablation therapy?
bowel perforation gallbladder perforation heat sink effect (increased time, reduced effect) grounding pad burns pacemaker resetting after procedure seeding
What complications can arise from overheating in ablation therapy?
bile duct strictures: central treat early, peripheral watch and wait
liver infarction / abscess formation (2%)
adjacent structure: diaphragm, chest wall, bowel, GB injury
