Assessment of the hepatic tumor extracellular matrix using elastin-specific molecular magnetic resonance imaging in an experimental rabbit cancer model

AbstractTo investigate the imaging performance of an elastin-specific molecular magnetic resonance imaging (MRI) probe with respect to the extracellular matrix (ECM) in an experimental hepatic cancer model. Twelve rabbits with hepatic VX2 tumors were examined using 3 T MRI 14, 21, and 28 days after tumor implantation for two subsequent days (gadobutrol, day 1; elastin-specific probe, day 2). The relative enhancement (RE) of segmented tumor regions (central and margin) and the peritumoral matrix was calculated using pre-contrast and delayed-phase T1w sequences. MRI measurements were correlated to histopathology and element-specific and spatially resolved mass spectrometry (MS). Mixed-model analysis was performed to assess the performance of the elastin-specific probe. In comparison to gadobutrol, the elastin probe showed significantly stronger RE, which was pronounced in the tumor margin (day 14–28: P ≤ 0.007). In addition, the elastin probe was superior in discriminating between tumor regions (χ2(4) = 65.87; P < 0.001). MRI-based measurements of the elastin probe significantly correlated with the ex vivo elastinstain (R = .84; P <0 .001) and absolute gadolinium concentrations (ICP-MS: R = .73, P <0 .01). LA-ICP-MS imaging confirmed the colocalization of the elastin-specific probe with elastic fibers. Elastin-specific molecular MRI is superior to non-specific gadolinium-based contrast agents in imaging the ECM of hepatic tumors and the peritumoral tissue.

Download Full-text

Native T1 Mapping Magnetic Resonance Imaging as a Quantitative Biomarker for Characterization of the Extracellular Matrix in a Rabbit Hepatic Cancer Model

Biomedicines ◽

10.3390/biomedicines8100412 ◽

2020 ◽

Vol 8 (10) ◽

pp. 412

Author(s):

Sarah Keller ◽

Tabea Borde ◽

Julia Brangsch ◽

Lisa C. Adams ◽

Avan Kader ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Extracellular Matrix ◽

Magnetic Resonance ◽

T1 Mapping ◽

Single Shot ◽

Hepatic Cancer ◽

Cancer Model ◽

Resonance Imaging ◽

Time Points ◽

Native T1

To characterize the tumor extracellular matrix (ECM) using native T1 mapping magnetic resonance imaging (MRI) in an experimental hepatic cancer model, a total of 27 female New Zealand white rabbits with hepatic VX2 tumors were examined by MRI at different time points following tumor implantation (day 14, 21, 28). A steady-state precession readout single-shot MOLLI sequence was acquired in a 3 T MRI scanner in prone position using a head-neck coil. The tumors were segmented into a central, marginal, and peritumoral region in anatomical images and color-coded T1 maps. In histopathological sections, stained with H&E and Picrosirius red, the regions corresponded to central tumor necrosis and accumulation of viable cells with fibrosis in the tumor periphery. Another region of interest (ROI) was placed in healthy liver tissue. T1 times were correlated with quantitative data of collagen area staining. A two-way repeated-measures ANOVA was used to compare cohorts and tumor regions. Hepatic tumors were successfully induced in all rabbits. T1 mapping demonstrated significant differences between the different tumor regions (F(1.43,34.26) = 106.93, p < 0.001) without interaction effects between time points and regions (F(2.86,34.26) = 0.74, p = 0.53). In vivo T1 times significantly correlated with ex vivo collagen stains (area %), (center: r = 0.78, p < 0.001; margin: r = 0.84, p < 0.001; peritumoral: r = 0.73, p < 0.001). Post hoc tests using Sidak’s correction revealed significant differences in T1 times between all three regions (p < 0.001). Native T1 mapping is feasible and allows the differentiation of tumor regions based on ECM composition in a longitudinal tumor study in an experimental small animal model, making it a potential quantitative biomarker of ECM remodeling and a promising technique for future treatment studies.

Download Full-text

Numerical Analysis of a Flexible Dual Loop Coil and its Experimental Validation for pre-Clinical Magnetic Resonance Imaging of Rodents at 7 T

Measurement Science Review ◽

10.1515/msr-2016-0037 ◽

2016 ◽

Vol 16 (6) ◽

pp. 294-299 ◽

Cited By ~ 1

Author(s):

S. Solis-Najera ◽

F. Vazquez ◽

R. Hernandez ◽

O. Marrufo ◽

A.O. Rodriguez

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Imaging System ◽

Ex Vivo ◽

Small Animal ◽

Magnetic Resonance Imaging System ◽

External Diameter ◽

Rf Coil ◽

Resonance Imaging ◽

Clinical Magnetic Resonance Imaging

Abstract A surface radio frequency coil was developed for small animal image acquisition in a pre-clinical magnetic resonance imaging system at 7 T. A flexible coil composed of two circular loops was developed to closely cover the object to be imaged. Electromagnetic numerical simulations were performed to evaluate its performance before the coil construction. An analytical expression of the mutual inductance for the two circular loops as a function of the separation between them was derived and used to validate the simulations. The RF coil is composed of two circular loops with a 5 cm external diameter and was tuned to 300 MHz and 50 Ohms matched. The angle between the loops was varied and the Q factor was obtained from the S11 simulations for each angle. B1 homogeneity was also evaluated using the electromagnetic simulations. The coil prototype was designed and built considering the numerical simulation results. To show the feasibility of the coil and its performance, saline-solution phantom images were acquired. A correlation of the simulations and imaging experimental results was conducted showing a concordance of 0.88 for the B1 field. The best coil performance was obtained at the 90° aperture angle. A more realistic phantom was also built using a formaldehyde-fixed rat phantom for ex vivo imaging experiments. All images showed a good image quality revealing clearly defined anatomical details of an ex vivo rat.

Download Full-text

Assessment of the systemic distribution of a bioconjugated anti-Her2 magnetic nanoparticle in a breast cancer model by means of magnetic resonance imaging

Journal of Nanoparticle Research ◽

10.1007/s11051-016-3594-8 ◽

2016 ◽

Vol 18 (9) ◽

Cited By ~ 3

Author(s):

L. F. E. Huerta-Núñez ◽

G. Cleva Villanueva-Lopez ◽

A. Morales-Guadarrama ◽

S. Soto ◽

J. López ◽

...

Keyword(s):

Breast Cancer ◽

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Magnetic Nanoparticle ◽

Cancer Model ◽

Resonance Imaging ◽

Systemic Distribution ◽

Breast Cancer Model

Download Full-text

Multidetector-row computed tomography and magnetic resonance imaging of atherosclerotic lesions in human ex vivo coronary arteries

Atherosclerosis ◽

10.1016/j.atherosclerosis.2004.01.041 ◽

2004 ◽

Vol 174 (2) ◽

pp. 243-252 ◽

Cited By ~ 79

Author(s):

Konstantin Nikolaou ◽

Christoph R Becker ◽

Michael Muders ◽

Gregor Babaryka ◽

Juergen Scheidler ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Computed Tomography ◽

Magnetic Resonance ◽

Coronary Arteries ◽

Ex Vivo ◽

Multidetector Row Computed Tomography ◽

Resonance Imaging ◽

Multidetector Row ◽

Atherosclerotic Lesions

Download Full-text

High-Resolution Magnetic Resonance Imaging of the Human Median Nerve

Neurorehabilitation and Neural Repair ◽

10.1177/0888439004267074 ◽

2004 ◽

Vol 18 (2) ◽

pp. 80-87 ◽

Cited By ~ 11

Author(s):

Archie Heddings ◽

Mehmet Bilgen ◽

Randolph Nudo ◽

Bruce Toby ◽

Terence McIff ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

High Resolution ◽

Peripheral Nerve ◽

Median Nerve ◽

Ex Vivo ◽

Imaging Techniques ◽

Proton Density ◽

Resonance Imaging ◽

Imaging Protocols

Objectives. It is widely accepted that peripheral nerve repairs performed within 6 weeks of injury have much better outcomes than those performed at later dates. However, there is no diagnostic technique that can determine if a traumatic peripheral nerve injury requires surgical intervention in the early postinjury phase. The objective of this article was to determine whether novel, noninvasive magnetic resonance imaging techniques could demonstrate the microstructure of human peripheral nerves that is necessary for determining prognosis and determining if surgery is indicated following traumatic injury. Methods. Ex vivo magnetic resonance imaging protocols were developed on a 9.4-T research scanner using spin-echo proton density and gradient-echo imaging sequences and a specially designed, inductively coupled radio frequency coil. These imaging protocols were applied to in situ imaging of the human median nerve in 4 fresh-frozen cadaver arms. Results. Noninvasive high-resolution images of the human median nerve were obtained. Structures in the nerve that were observed included fascicles, interfascicular epineurium, perineurium, and intrafascicular septations. Conclusion. Application of these imaging techniques to clinical scanners could provide physicians with a tool that is capable of grading the severity of nerve injuries and providing indications for surgery in the early postinjury phase.

Download Full-text