Diffusion-weighted imaging of the breast & ultra-high gradients

Radiology

Head of Department:
Prof. Dr. med. Michael Uder

Diffusion-weighted imaging of the breast and ultra-high gradient approaches

In cooperation with the University Hospital Freiburg and the German Cancer Research Center (DKFZ, Heidelberg), a novel high-power diffusion probe for MR mammography is being developed (Fig. 1). The project is funded by the Deutsche Forschungsgemeinschaft (DFG) (project number 326944748, http://gepris.dfg.de/gepris/projekt/326944748). The aim of the project is to increase the power of diffusion weighted imaging so that diffusion processes on the scale of cell sizes can be detected. In order to do that, very high gradient fields (one order of magnitude larger than currently clinically available) are needed. The envisaged breast gradient coil could lead to an increase in diagnostic power of MR mammography by providing access to tissue microstructure measured in vivo. The construction of the gradient coil is carried out by the group around Dr. Maxim Zaitsev in Freiburg [1]. The group at the DKFZ (Prof. Dr. Mark Ladd) develops the RF coil and runs simulations on nerve stimulation limits. In Erlangen, we develop diffusion weighted sequences that can be employed with the new hardware and calculate the requirements the gradient coil needs to meet for diffusion experiments [2].

Figure 1. Diffusion probe concept. The diffusion probe, which includes gradient coil and RF coil, shall be used as a device that is run in combination with an MRI scanner. It delivers extremely strong magnetic field gradients that are not obtainable with classical designs and that allow for investigation of novel diffusion contrasts that are currently unattainable.

Using a clinically available gradient coil for MR mammography, a study on diffusion kurtosis imaging was conducted in cooperation with radiologists of the University Hospital Erlangen [3]. The breast tissue’s kurtosis value can be used for differentiation of malignant and benign lesions (see Figure 2) and for tumor classification. It was examined how the kurtosis performs in comparison to the diffusion coefficient and if subgroups of benign lesions can be identified via their kurtosis value. In addition to that, kurtosis values were tested for significant differences between tumor gradings. Moreover, several further clinical studies on breast MRI have been performed in cooperation with colleagues from the German Cancer Research Center [4-6].

Figure 2. Diffusion kurtosis imaging. Sample kurtosis images of a) two cancerous lesions (invasive carcinoma of no special type), and b) a benign lesion (fibroadenoma). The color bars indicate the unitless kurtosis values which are overlaid on a diffusion-weighted image with b = 1500 s/mm². The malignant lesions have higher kurtosis values than the benign lesion.

In order to guarantee optimum patient care, it is essential to obtain comparable images at scanners with different field strengths. In further projects, effects of fat saturation methods and impact of the breathing cycle on the DWI measurement at 1.5 T and 3 T are explored. Furthermore, a study on sensitivity of high b-value DWI for lesion detection is currently running on two 3 T scanners and one 1.5 T device. Moreover, we are working on and evaluate scan time reduction approaches [7].

 

[1] Jia F, Littin S, Kroboth S, Yu H, Palm T, Laun FB, Ladd ME, Zaitsev M.
Design of breast gradient coil with the control of field nonlinearity.
Proc Intl Soc Mag Reson Med. 2018;26:1757.

[2] Palm T, Martin J, Hensel B, Jia F, Zaitsev M, Kuder TA, Ladd ME, Uder M, Laun FB.
Impact of slew rates on the performance of a novel high-gradient breast diffusion probe.
Proc Intl Soc Mag Reson Med. 2018;26:1622.

[3] Palm T, Wenkel E, Ott S, Janka R, Uder M, Bickelhaupt S, Ladd ME, Zaitsev M, Hensel B, Laun FB.
Genauigkeit der Diffusions-Kurtosis-Bildgebung bei der Differenzierung von gutartigen und bösartigen Brust-Läsionen.
49 Jahrestagung der Deutschen Gesellschaft für Medizinische Physik und 21 Jahrestagung der Deutschen Sektion der ISMRM; 2018; Nürnberg.

[4] Bickelhaupt S, Steudle F, Paech D, Mlynarska A, Kuder TA, Lederer W, Daniel H, Freitag M, Delorme S, Schlemmer HP, Laun FB.
On a fractional order calculus model in diffusion weighted breast imaging to differentiate between malignant and benign breast lesions detected on X-ray screening mammography.
PLoS One. 2017 Apr 28;12(4):e0176077.

[5] Bickelhaupt S, Jaeger PF, Laun FB, Lederer W, Daniel H, Kuder TA, Wuesthof L, Paech D, Bonekamp D, Radbruch A, Delorme S, Schlemmer HP, Steudle FH, Maier-Hein KH.
Radiomics Based on Adapted Diffusion Kurtosis Imaging Helps to Clarify Most Mammographic Findings Suspicious for Cancer.
Radiology. 2018 Jun;287(3):761-770.

[6] Bickelhaupt S, Laun FB, Tesdorff J, Lederer W, Daniel H, Stieber A, Delorme S, Schlemmer HP.
Fast and Noninvasive Characterization of Suspicious Lesions Detected at Breast Cancer X-Ray Screening: Capability of Diffusion-weighted MR Imaging with MIPs.
Radiology. 2016 Mar;278(3):689-97.

[7] Ohlmeyer S, Laun FB, Palm T, Janka R, Weiland E, Uder M, Wenkel E.
Simultaneous multi-slice echo planar imaging for accelerated diffusion-weighted imaging of malignant and benign breast lesions.
Inv. Radiology. 2019 Aug;54(8):524-530.  

 
Contact
Prof. Dr. rer. nat. Armin Nagel
phone: +49 9131 85-25900
DECT: +49 9131 85-45618
e-mail: armin.nagel@uk-erlangen.de
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Prof. Dr. rer. nat. Frederik B. Laun
phone: +49 9131 85-22309
DECT: +49 9131 85-45622
e-mail: frederik.laun@uk-erlangen.de
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