Early prediction of anticancer effects with diffusion-weighted MR imaging in patients with colorectal liver metastases following selective internal radiotherapy.
OBJECTIVE
To prospectively evaluate diffusion-weighted imaging (DWI) for early prediction of tumour response in patients with colorectal liver metastases following selective internal radiotherapy (SIRT).


METHODS
We evaluated 41 metastases in 21 patients, age 62.9 ± 9.9 years. All patients underwent magnetic resonance imaging (MRI) including breath-hold echoplanar DWI sequences. Imaging was performed before therapy (baseline MRI), 2 days after SIRT (early MRI) as well as 6 weeks later (follow-up MRI). Tumour volume (TV) and intratumoural apparent diffusion coefficient (ADC) were measured independently by two radiologists at all time points.


RESULTS
Metastases were categorised as responding lesions (RL; n = 33) or non-responding lesions (NRL; n = 8) according to changes in TV after 6 weeks. We found an inverse correlation of changes in TV and ADC at follow-up MRI with a Pearson's correlation coefficient of r = -0.66 (p < 0.0001). On early MRI, no significant changes in TV were found for either RL or NRL. Conversely, ADC decreased significantly in RL by 10.7 ± 8.4% (p < 0.0001). ADC increased in NRL by 9.6 ± 20.8%, which was not statistically significant (p = 0.40).


CONCLUSIONS
DWI was capable of predicting therapy effects of SIRT in patients with colorectal hepatic metastases as early as 2 days following treatment.
Dudeck
Oliver
O
Department of Radiology and Nuclear Medicine, University of Magdeburg, Magdeburg, Germany. oliver.dudeck@med.ovgu.de
Zeile
Martin
M
Wybranski
Christian
C
Schulmeister
Alice
A
Fischbach
Frank
F
Pech
Maciej
M
Wieners
Gero
G
Rühl
Ricarda
R
Grosser
Oliver
O
Amthauer
Holger
H
Ricke
Jens
J
D000328:Adult; D000368:Aged; D001918:Brachytherapy; D015179:Colorectal Neoplasms / Q000473:pathology*; D003131:Combined Modality Therapy; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006498:Hepatectomy; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000532:radiotherapy / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D015021:Yttrium Radioisotopes / Q000627:therapeutic use*
D015021:Yttrium Radioisotopes