Quantification of Magnetic Nanoparticles in <i>ex vivo</i> Colorectal Lymph Nodes

Molenaar, Lennert; Loosdrecht, Melissa M. Horstman – van de; Alic, Lejla; Baarlen, Joop van; Meijerink, Jeroen J. H. J.; Haken, Bennie ten; Broeders, I. A. M. J.; Lips, Daan J.

doi:10.1142/s1793984422500064

Cited by 2 publications

(2 citation statements)

References 20 publications

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“…The SLN (situated in a glass tube) was placed in an alternating magnetic field generated by an excitation coil to measure the dynamic magnetisation curve. The specific SPaQ settings used involve AC amplitude of 0.83 mT, AC frequency of 2.5 kHz and DC field strength of 4.99 mT [13]. The evaluation was supported by a lookup table (LUT) tailored to quantify the accumulation of the Magtrace magnetic tracer within LN through the utilisation of magnetic readout counts [14].…”

Section: Assessment Of Iron Content By Spaqmentioning

confidence: 99%

Magnetic procedure for sentinel lymph node detection and evaluation of metastases: design and rationale of the Lowmag trial

Christenhusz,

Dassen,

van der Schaaf

et al. 2024

BMC Methods

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Background Primary tumour biology and axillary lymph node status are key prognostic factors in breast cancer treatment. The LowMag trial introduced a magnetic sentinel lymph node biopsy procedure using a superparamagnetic iron oxide (SPIO) tracer and a handheld magnetometer as a radiation-free alternative for axillary staging. The trial aimed to assess a low-dose magnetic tracer for non-invasive preoperative evaluation of lymph node metastases and intraoperative sentinel lymph node detection. Methods Patients with confirmed invasive breast cancer or ductal carcinoma in situ, eligible for sentinel lymph node biopsy, were included in the LowMag trial. The sentinel lymph nodes were detected perioperatively using Sentimag® and inked to maintain spatial orientation between MRI and histopathology. The amount of iron was estimated using two magnetic devices: SPaQ and Sentimag®. Additional ex vivo MRI was performed with a low-field MRI system. After being buffered in formalin, the sentinel lymph nodes were sectioned perpendicular to the MRI planes, consecutively sliced at 2 μm intervals, and stained with H&E, Perls Prussian blue, CK8/18, and CD68. Results In an interim assessment of 20 sentinel lymph nodes, two contained metastases. The analysis revealed good concordance in uptake between the magnetic and radioactive tracers, with a median iron content of 19.21 µg. In healthy sentinel lymph nodes, iron particles were found in both the subcapsular space and sinusoids, with macrophages nearby. Healthy regions within metastatic lymph nodes showed similar behaviour to healthy nodes. In metastatic sites, iron pigment presence was reduced, especially in areas occupied by tumour cells. A healthy lymph node with low iron content displayed a large central fatty region without iron uptake but confirmed iron in sinusoidal macrophages. The metastatic lymph node had subcapsular and parenchymal tumour cells in the central region, with limited infiltration into nearby adipose tissue and no local iron enhancement. However, iron deposits were detected within the sinusoids. Discussion The MRI images effectively distinguish between fat, nodal tissue, and the SPIO tracer, either through signal intensity or texture. This demonstrates the potential for sentinel lymph node imaging using a low-field MRI system.

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Section: Assessment Of Iron Content By Spaqmentioning

confidence: 99%

Magnetic procedure for sentinel lymph node detection and evaluation of metastases: design and rationale of the Lowmag trial

Christenhusz,

Dassen,

van der Schaaf

et al. 2024

BMC Methods

Self Cite

View full text Add to dashboard Cite

show abstract

“…The SLN (situated in a glass tube) was placed in an alternating magnetic eld generated by an excitation coil to measure the dynamic magnetisation curve. The speci c SPaQ settings used involve AC amplitude of 0.83 mT, AC frequency of 2.5 kHz and DC eld strength of 4.99 mT [13]. The evaluation was supported by a lookup table (LUT) tailored to quantify the accumulation of the Magtrace magnetic tracer within LN through the utilisation of magnetic readout counts [14].…”

Section: During the Surgerymentioning

confidence: 99%

Magnetic procedure for sentinel lymph node detection and evaluation of metastases: Design and rationale of the Lowmag trial

Christenhusz,

Dassen,

Schaaf

et al. 2023

Preprint

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Background Primary tumour biology and axillary lymph node status are crucial prognostic factors in breast cancer treatment. The LowMag trial introduced a magnetic sentinel lymph node biopsy (SLNB) procedure using a Superparamagnetic Iron Oxide (SPIO) tracer and handheld magnetometer as a radiation-free alternative for axillary staging. The objective of LowMag trial was to assess a low-dose magnetic tracer for non-invasive preoperative evaluation of lymph node metastases and intraoperative SLN detection. Methods Patients with confirmed invasive breast cancer or ductal carcinoma, eligible for SLNB, were included in the LowMag trial (NTR 4858, http://www.trialregister.nl) consisted of radioactive and magnetic SLNB. The SLNs were perioperatively detected by Sentimag®, and inked to keep track of spatial orientation between MRI and histopathology. Amount of iron was estimated post-surgery using two magnetic devices: SPaQ and Sentimag®. Additional ex vivo MRI was acquired using low-field MRI system (Pure Devices). After buffered in formalin fixation, the LN were lamellated perpendicular to the MRI planes, consecutively sectioned at 2 µm distance and stained with H&E, Perls Prussian blue, CK8/18 and CD68. Results In an interim assessment of 20 LNs (nine patients) two LNs from two patients contained a metastasis. The analysis reviled good uptake concordance between magnetic and radioactive tracer with median amount of iron trapped was 19.21 µg (ranging from 0.1 pg to 109 µg). Within healthy LNs, iron particles were observed in both the subcapsular space and sinusoids, with macrophages located in their proximity. Healthy regions within metastatic LNs exhibit a behaviour similar to that of the healthy LNs. In the metastatic sites, there was a reduced presence of iron pigment, particularly in the areas occupied by tumour cells. The healthy LN with low iron content shows a large fatty region in the centre of the node without iron uptake, and confirmed iron in the sinusoidal macrophages. The metastatic LN shows subcapsular and parenchymal tumour cells located in the central region, with limited infiltration into the nearby adipose tissue, without presence of local iron enhancement. However, iron deposits are were detected within the sinusoids. Conclusion The MRI images clearly differentiate between fat, nodal tissue and SPIO tracer (either in signal intensity or in texture), demonstrating a potential of LN imaging using a low-field MRI system.

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Quantification of Magnetic Nanoparticles in ex vivo Colorectal Lymph Nodes

Cited by 2 publications

References 20 publications

Magnetic procedure for sentinel lymph node detection and evaluation of metastases: design and rationale of the Lowmag trial

Magnetic procedure for sentinel lymph node detection and evaluation of metastases: design and rationale of the Lowmag trial

Magnetic procedure for sentinel lymph node detection and evaluation of metastases: Design and rationale of the Lowmag trial

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