Purpose This study assessed the capability of magnetic
resonance (MR) diffusion-weighted imaging (DwI) with
measurement of apparent diffusion coefficient (ADC) in
both predicting and evaluating the response to chemotherapy
(CHT) of liver metastases by itself and along with
preliminary dimensional assessment.
Methods and materials Patients affected by liver metastases
from cancers of the digestive tract and breast were
prospectively enrolled and underwent computed tomography
and MR-DwI before CHT (time 0) and 20–25 days after
the beginning of the second cycle (time 3). Moreover, MRDwI
was performed 10–15 (time 1) and 20–25 days (time 2)
after the beginning of the first cycle. Maximum diameter and
mean ADC value (910-3 mm2/s) of metastases were evaluated.
Lesions were classified as progressive disease (PD),
stable disease (SD) or partial response (PR) according to
dimensional changes between time 0 and time 3, following
RECIST 1.1 indications. Clinically, PD lesions were defined
as nonresponding (NR), and SD and PR lesions as
responding (R). Analysis of variance and ROC analyses
were performed (significance at p\0.05).
Results Eighty-six metastases (33 patients) were classified as
follows: 15 PD, 39 SD and 32 PR without significant differences
in mean ADC values among the groups before CHT and
at all corresponding times.The meanADCvalues ofSDand PR
groups at times 1 (respectively 1.66 ± 0.36 and 1.59 ± 0.23),
2 (1.72 ± 0.42 and 1.68 ± 0.37) and 3 (1.86 ± 0.44 and
1.73 ± 0.39) were significantly higher than the corresponding
values at time 0 (1.50 ± 0.30 and 1.39 ± 0.33). An accurate
cutoff value ofADC increase or diameter decrease for the early
identification of R or NR lesions was not found.
Conclusion The pretreatment ADC value of a liver
metastasis does not seem useful in predicting the CHT
outcome. A trend towards early ADC increase, alone or
occurring with dimensional decrease, may be a good
indicator of a responding lesion.
