Laser-induced thermotherapy for the treatment of liver metastasis. Correlation of gadolinium-DTPA-enhanced MRI with histomorphologic findings to determine criteria for follow-up monitoring.
OBJECTIVE
To evaluate gadolinium (Gd)-diethylenetriamine-pentaacetic-acid (DTPA)-enhanced magnetic resonance imaging (MRI) for follow-up monitoring of laser-induced thermotherapy (LITT) and to determine a useful examination schedule.


METHODS
LITT of the liver was performed in 55 rabbits using a neodymium: yttrium-aluminum-garnet (Nd:YAG) laser (4-W power output, 840-s exposure time). Gd-DTPA MRI and histologic examinations were performed at different times (0-168 days).


RESULTS
Laser-induced lesions underwent regeneration and volume size reduction (69% after 168 days). The correlation coefficient (MR vs. macroscopic analysis) for the mean lesion diameter was r = 0.96. Histology of lesions comprised the four zones that correlated best with MRI findings. Coagulation necroses immediately after LITT was seen as an area of no enhancement on Gd-DTPA MRI. Circular enhancement was first seen 72-96 h after LITT, which was due to early mesenchymal proliferation.


CONCLUSIONS
Gd-DTPA MRI is a good monitoring procedure for LITT. MRI should be performed 24 and 96 h after LITT.
Germer
C
C
Department of General, Vascular, and Thoracic Surgery, University Hospital, Benjamin Franklin Freie Universität Berlin, Hindenburgdamm 30, 12200 Germany.
Isbert
C M
CM
Albrecht
D
D
Ritz
J P
JP
Schilling
A
A
Roggan
A
A
Wolf
K J
KJ
Müller
G
G
Buhr
H
H
D000818:Animals; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006979:Hyperthermia, Induced / Q000379:methods*; D007089:Image Enhancement; D007834:Lasers; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000473:pathology / Q000628:therapy*; D008279:Magnetic Resonance Imaging; D008991:Monitoring, Physiologic; D011817:Rabbits
D003287:Contrast Media; D019786:Gadolinium DTPA