[Characteristics of necrosis after laser-induced thermotherapy in contrast-enhanced MRI and implications for treatment success].
OBJECTIVE
This article reports on the use of magnetic resonance imaging to access the post-interventional necrosis volume of liver metastases immediately after and 48 hours after LITT.


METHODS
In this prospective study, 56 liver metastases from 39 patients (16 females, 23 males, mean age 60.4 years) underwent LITT. The 56 metastases were divided into 4 groups according to the ablation strategy (dependent on multi-applicator technique and laser duration). Groups I and II were treated with an applicator and a time of ablation greater than 15 minutes and 20 minutes, respectively. In groups III and IV the multi-applicator technology with 3 or 4 applicators and a constant ablation time of 20 minutes were used. With the help of heightened contrast MRI of the liver, the portrayal of the post-interventional necrosis was conducted immediately after LITT and 48 hours after LITT. The post-interventional controls after 48 hours were performed during the inpatient stay. The protocol was complemented by an outpatient long-term control after more than 3 months.


RESULTS
The local tumor control rate was initially 96.4%. After 3 months it decreased to 92.1%. The mean necrosis volume directly after LITT was: Group I (n = 11; 1 applicator, 30 watt, 10-15 minutes) 6.69 cm(3); Group II (n = 13; 1 applicator, 30 watt, 20 minutes) 10.95 cm(3); Group III (n = 28; 2 applicator, 30 watt, 10-15 minutes) 21.47 cm(3); Group IV (n = 4; 3 applicator, 30 watt, 20 minutes) 40.20 cm(3). In comparison, the necrosis volume after 48 hours increased: Group I 10.56 cm(3); Group II 15.11 cm(3); Group III 31.33 cm(3), Group IV 55.73 cm(3)).


CONCLUSIONS
After 48 hours a progressive increase of post-interventional necrosis volumes compared to volumes directly after LITT was able to be observed. An MRI control after 48 hours, as opposed to an MRI control directly after intervention, is a better indicator for post-interventional success after LITT.
Kühn
J P
JP
Institut für Diagnostische Radiologie und Neuroradiologie, Ernst-Moritz-Arndt-Universität. kuehn@uni-greifswald.de
Puls
R
R
Wallaschowski
H
H
Heidecke
C D
CD
Rosenberg
C
C
Hosten
N
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement; D053685:Laser Therapy; D008099:Liver / Q000473:pathology / Q000601:surgery; D008113:Liver Neoplasms / Q000473:pathology / Q000556:secondary* / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D010166:Palliative Care; D011446:Prospective Studies; D016896:Treatment Outcome
D003287:Contrast Media