Can diffusion tensor anisotropy indices assist in breast cancer detection?

Abstract

Water diffusion anisotropy in the healthy breast can be similarly mapped by the normalized indices and by λ -λ . However, the normalized anisotropy indices fail to differentiate cancer from normal breast tissue, whereas λ -λ can assist in differentiating cancer from normal breast tissue. J. Magn. Reson. Imaging 2016;44:1624-1632.

Diffusion-weighted breast MRI: Clinical applications and emerging techniques

“…Malignant transformation may in turn cause blockage of the ducts by proliferating neoplastic cells and loss of structured organization, resulting in a concomitant reduction of anisotropy measures, Figure . Indeed, two studies demonstrated FA to be significantly reduced in malignancies versus normal breast tissue, although several other DTI studies found no difference …”

“…Typical DWI acquisitions have Δ in the range of 35–50 ms, corresponding to an approximate (one dimensional) diffusion displacement of 14–17 μm for unrestricted free water at body temperature (D∼3 × 10 ‐3 mm 2 /s). Diffusion time was found to affect anisotropy measures of normal fibroglandular tissue, with reduced anisotropy values observed for all indices following shortening of the diffusion time from 47 to 33 ms …”

“…Indeed, two studies demonstrated FA to be significantly reduced in malignancies versus normal breast tissue, 111,112 although several other DTI studies found no difference. [113][114][115][116] In differentiating breast lesions, a general consensus exists across studies regarding significantly reduced diffusivity (ADC or MD) in malignant tumors versus benign lesions. However, there are conflicting results regarding the diagnostic utility of the anisotropy indices, with several studies reporting lower FA in benign lesions compared with malignant lesions 27,112,113,117 and others finding no difference in FA, 111,114,115 warranting further investigation.…”

“…However, there are conflicting results regarding the diagnostic utility of the anisotropy indices, with several studies reporting lower FA in benign lesions compared with malignant lesions 27,112,113,117 and others finding no difference in FA, 111,114,115 warranting further investigation. One study 116 reported the eigenvalue difference (k 1 -k 3 ), another measure of anisotropy, to significantly discriminate malignancy. Figure 12 summarizes recent studies reporting DTI metrics in human breast cancers, 27,[111][112][113][114][115][116][117][118] with corresponding study characteristics reported in Table 1.…”

Microstructural models for diffusion MRI in breast cancer and surrounding stroma: an ex vivo study

“…Furthermore, the source of anisotropy is uncertain: a preclinical breast cancer model observed lower FA in hypoxic regions with lower collagen fibre content, but the differences between normoxic and hypoxic FAs were small, approximately 0.03. Other groups have suggested partial restriction in the breast ducts, although the average duct diameter (approximately 90 μm in normal breast and larger in patients with ductal carcinoma in situ ) is much larger than the average distance travelled by water molecules during typical diffusion MRI experiments.…”