[Fusion of CT and PET data: methods and clinical relevance for planning laser-induced thermotherapy of liver metastases].
OBJECTIVE
Catheter-placement in liver metastases is difficult when the lesions are not visible on plain images. We evaluated the use of image fusion using CT and PET data, providing information on anatomy and liver lesions, respectively.


METHODS
Plain CT of the liver and whole body FDG-PET were performed in 28 patients with colorectal carcinoma in preparation for laser-induced thermotherapy. Fusions of image data and 2D-visualisation were performed and evaluated with regard to quality of the registration, number of detected lesions and influence of the procedure on laser-induced thermotherapy. Image fusion was performed using an algorithm which was developed by our group.


RESULTS
84 focal liver lesions were visible on CT, 107 on PET images. This means that CT guided catheter placement would have to be performed "blindly" in 23 lesions. In 6 patients previously unknown extra-hepatic tumor deposits were seen on PET images (local recurrence, 2 extrahepatic metastases, 2 second primaries).


CONCLUSIONS
Hot spots from metastases, which are difficult to locate on PET images alone, may be identified on images generated by fusion of CT and PET data. These images facilitate an interventional approach to liver lesions which are not visible on plain CT. As PET allows for whole body screening, it helps identifying patients who would not profit from laser-induced thermotherapy.
Hosten
N
N
Strahlenklinik und Poliklinik, Humboldt-Universität zu Berlin. norbert.hosten@charite.de
Kreissig
R
R
Puls
R
R
Amthauer
H
H
Beier
J
J
Rohlfing
T
T
Stroszczynski
C
C
Herbel
A
A
Lemke
A J
AJ
Felix
R
R
D000465:Algorithms; D015179:Colorectal Neoplasms / Q000473:pathology / Q000628:therapy; D019788:Fluorodeoxyglucose F18; D006801:Humans; D006979:Hyperthermia, Induced; D007091:Image Processing, Computer-Assisted; D053685:Laser Therapy; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary* / Q000628:therapy*; D008279:Magnetic Resonance Imaging; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000628:therapy; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D014055:Tomography, Emission-Computed; D014057:Tomography, X-Ray Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18