Purpose: To investigate whether quantitative Diffusion-Weighted Imaging
(DWI) parameters predict elevated levels of MIB-1 proliferation index in
patients with breast cancer.
Methods and Materials: We retrospectively enrolled 52 patients with biopsyand
surgically-proven invasive cancers (n=52), who underwent preoperative
breast Magnetic Resonance imaging (MRI) on a 1.5 T magnet. MRI
examination included a Single Shot Echoplanar DWI sequence with b values of
0 and 1000s/mm2. For each lesion, two experienced readers in consensus
measured the apparent diffusion coefficient (ADC) (on the ADC maps) and
lesion-to-background-ratio (LBGR) (on b=1000 s/mm2 images). Based on
immunohistochemistry results, we then compared mean ADC and LBGR
values between MIB-1-positive (> 14%) and MIB-1-negative (14%) patients
using the unpaired T-test.
Results: Patients were assessed as MIB-1-positive and MIB-1-negative in
23/52 (44.2%) and 29/52 (55.8%), respectively. ADC values were significantly
(p < 0.05) lower in MIB-1-positive patients (0.86x10-3 s/mm2; 95%IC 0.80 -
0.92) compared to MIB-1-negative ones (1.01x10-3 s/mm2; 95%IC 0.91-1.11).
On the contrary, we showed no significant difference in LBGR between MIB-1-
positive (6.73; 95%IC 4.15-9.32) and MIB-1-negative (9.14; 95%IC 4.45-12.82)
women.
Conclusion: Lower ADC values at DWI are associated with elevated MIB-1
proliferation index in patients with invasive breast cancer.
