Double contrast MRI of thermally ablated liver metastases.
OBJECTIVE
To investigate the ability of double contrast MRI (enhancement with iron oxide and gadopentetate dimeglumine) to increase the difference in contrast between various tissues after thermal ablation of liver metastases.


METHODS
12 patients were imaged after MR-guided laser-induced thermotherapy (LITT). Imaging was performed with a 1.5T MR system. Nonenhanced, iron oxide-enhanced and double contrast images were acquired using T (1)-weighted GRE and T (2)-weighted TSE sequences. Iron oxide imaging was performed 10 min after injection of 1.4 ml ferucarbotran (Resovist(R), Schering AG Berlin, Germany) and double contrast imaging 60 sec after the additional injection of 0.1 mmol/kg body weight gadopentetate dimeglumine (Magnevist(R), Schering AG Berlin, Germany). Qualitative and quantitative assessment was performed on induced necroses, residual or recurrent tumor tissue and metastatic tissue untreated at the time of the study.


RESULTS
Iron oxide-enhanced T (1) GRE images demonstrated the highest contrast between ablated hyperintense tissue and iron accumulating and resultant hypointense liver parenchyma. Due to Gd enhancement, double contrast T (1)-weighted GRE images displayed the highest change in signal intensity in vital tumor tissue compared to ablated tissue and iron oxide accumulating liver parenchyma (p < 0.01).


CONCLUSIONS
First observations indicate that LITT of hepatic metastases can be better followed with double contrast MRI, which displays increased contrast due to Gd enhancement of perfused tumor tissue and signal intensity loss in iron oxide accumulating hepatic parenchyma. Induced necrosis does not change its signal intensity at all after injection of iron oxide and Gd-containing contrast media.
Puls
R
R
Institut für Radiologie, Campus Charité Mitte, Berlin. puls@charite.de
Kröncke
T J
TJ
Klüner
C
C
Gaffke
G
G
Stroszczynski
C
C
Albrecht
T
T
Speck
U
U
Hamm
B
B
D000368:Aged; D003287:Contrast Media; D005260:Female; D006801:Humans; D006979:Hyperthermia, Induced; D007091:Image Processing, Computer-Assisted; D007501:Iron / Q000378:metabolism; D008113:Liver Neoplasms / Q000175:diagnosis / Q000556:secondary* / Q000628:therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged
D003287:Contrast Media; D007501:Iron