Repeatability on diffusion MRI measurements on the different numbers of b values and excitations of the breast and its comparison with lactating breasts

Mami Iima^{1,2}, Masako Kataoka^{1}, Shotaro Kanao^{1}, Natsuko Onishi^{1}, Makiko Kawai^{1}, Akane Ohashi^{1}, Rena Sakaguchi^{1}, and Kaori Togashi^{1}

13 non-lactating
and 3 lactating volunteers were recruited in this IRB approved prospective study. Breast MRI
was performed using a 3-T system (Trio, B17; Siemens AG) equipped with a
dedicated 16-channel breast array coil. The following fat-suppressed DWI

・16 b values of 0, 5, 10, 20, 30, 50, 70, 100, 200, 400, 600, 800, 1000, 1500, 2000, 2500 ^{2 }

・5 b values of 0, 100, 200, 1500 and 2500 ^{2 }

For both ^{2}, matrix 80×166, and slice thickness 3.0 mm.

ROIs were placed onto the normal breast tissue and images processing was performed using software implemented in Matlab (Mathwork, Natick, MA) comprising the following steps:

1/Noise correction to handle Rician noise at each b value:

S^{2} = Sn^{2} + NCF [1]

2/The corrected signal acquired with b>200 s/mm² was fitted using the

S/So = exp[-bADCo + K(bADCo)²/6] [2]

3/Then, the fitted diffusion signal component was subtracted from the corrected raw signal acquired with b<200s/mm² and the remaining signal was fitted using the IVIM model (4) to get estimates of the flowing blood fraction,

Additionally a synthetic ADC

sADC200-1500 =

The IVIM/DWI parameters were calculated from the datasets acquired with 16 b values (1 NEX), 5 b values (1 NEX), and 5 b values (3 NEX). The reproducibility for each parameter was assessed using intra-class correlation coefficients (ICCs) with absolute agreement.

1. Partridge

2. Chabert S et al. Relevance of the information about the

3. Jensen JH et al. MRI quantification of non-Gaussian water diffusion by

4. Iima M et al. Quantitative Non-Gaussian Diffusion and Intravoxel Incoherent Motion Magnetic Resonance Imaging: Differentiation of Malignant and Benign Breast Lesions. Investigative Radiology. 2015;50:205-11.

5. Nissan N et al. Diffusion-Tensor MR Imaging of the Breast: Hormonal Regulation. Radiology.2014:271:672-680.

6. Iima M et al. Clinical Intravoxel Incoherent Motion and Diffusion MR Imaging: Past, Present and Future. Radiology. (

Figure 1: Fat suppressed T2 weighted image and DWI image (b=200s/mm^{2}) from 16b value and 5b value datasets of the non-lactating (upper row) and lactating (lower row) volunteer. There was no remarkable difference of the DWI image quality beween 16 b values and 5 b values.

Table 1: Diffusion and IVIM MRI parameters according to the different numbers of b values and excitations (mean±SD). The acquisition time for 16 b
values (1 NEX), 5 b values (1 NEX), and 5 b values (3 NEX) was 3min 55sec, 1min 10sec, and 3min 30sec, respectively. No significant difference of
the parameters was observed
among the different numbers of b values or excitations.

Table 2: ICC comparing the datasets using different combination of b values and
excitations (mean and 95% CI). A good agreement in diffusion parameters was observed among
the different numbers of b values or excitations.

Figure 2: Comparisons of diffusion and IVIM
MRI parameters between non-lactating and lactating volunteers. Do and sADC200-1500 decreased, while K and fIVIM increased in women with lactation period.

Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)

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