Clinical applications of MARS technology

Measure multiple contrast agents simultaneously

CT has traditionally been limited to the use of a single contrast agent per scan. Spectral CT gives researchers a tool that can quantify a number of contrast agents as well as intrinsic markers such as lipid, bone and soft tissue. Tracking multiple biomarkers simultaneously provides a way to monitor multiple processes non-invasively.

Downloadable data sets include mouse data and phantom data.

M. Moghiseh, et al. (2016). Discrimination of Multiple High-Z Materials by Multi-Energy Spectral CT– A Phantom Study. JSM Biomed Imaging Data Pap 3(1): 1007. Read paper.

N. Anderson, et al. Spectroscopic (multi-energy) ct distinguishes iodine and barium contrast material in MICE. European Radiology, vol. 20, pp. 2126–2134, 2010. Read paper.

R .K. Roeder, et al. Probes for Molecular Imaging with Computed Tomography and Application to Cancer Imaging. Proc. SPIE, 10132, 101320X (2017). Read paper.

A mouse model of multiple contrast agents

Gold nanoparticles located in the lungs, iodine found in the bladder and kidneys, and gadolinium in the stomach and intestines. Soft tissues are identified in blue and bones in white.

Take a closer look inside with the magic lens tool

The magic lens tool is used to strip away the layers of bone, fat and water to reveal our area of interest – the heart and lungs

Quantification has never been easier

Are all the greys blurring together? MARS spectral CT offers seamless material differentiation and quantification, down to μg/μL concentrations.

A new way to image cancer

MARS scanning opens the door to targeted imaging probes on CT.

Knowing whether an antibody-based treatment has reached its target tissue can be difficult. MARS spectral CT offers a method to track nanoparticles, allowing preclinical researchers to have confidence that their treatment has reached their target cells.

Lighting up tumour neovascularization using nanoparticles

A tumour was placed under the flank of the animal. Small gold nanoparticles (5 nm) were injected. The non-functionalized nanoparticles accumulate in areas of neovascularization (e.g. tumours) where vessels are more leaky.

Imaging specific binding of antibody-gold nanoparticle complexes in vitro

(a), (b), (c) calibration standards of gold chloride
(d) Ovarian cancer cells incubated with gold nanoparticles targeted to a surface marker of ovarian cancer (Rituximab)
(e) Ovarian cancer cells with gold nanoparticles targeted to breast cancer (Herceptin)

Case Study

Researchers at the University of Notre Dame have successfully targeted breast microcalcification using modified gold nanoparticles in a mouse model. MARS scanning of excised tissue showed co-localisation of the gold nanoparticles and microcalcification.

Roeder et al. Proc. SPIE, 2017

Better soft tissue discrimination

Spectral imaging provides better soft tissue contrast than is available with traditional x-ray systems. This enables imaging and distinguishing pathological features of cardiovascular disease at high spatial resolution, for example the components of atherosclerotic plaque. Alternatively it can be used to better characterise muscles, bone and fat.

Downloadable data set of lamb meat.

R. Aamir, et al. MARS spectral molecular imaging of lamb tissue: data collection and image analysis. Journal of Instrumentation, vol. 9, no. 02, p. P02005. Read paper.

Profiles of lipid (beige), calcium (white) and soft tissue (red) in lamb steak (left) and excised atherosclerotic plaque (right)

Go beyond just the picture to quantitative imaging

MARS spectral CT allows researchers to easily quantify early biochemical changes in cartilage, improving detection of osteoarthritis and crystal arthropathies.

K Rajendran, et al. Quantitative imaging of excised osteoarthritic cartilage using spectral CT. Eur Radiol (2017) 27:384–392. DOI 10.1007/s00330-016-4374-7 Read paper.

Right: MARS image of a tibial plateau with iodine contrast. The amount of iodine (red) penetration into the cartilage layer shows areas of decreased glcyoaminoglycans (GAGs), an early indication of osteoarthritis.

See both structural and material changes in bone health in a single scan

MARS enables both structural, and material information to be measured simultaneously. This means that bone mineralisation or bone densitometry can be measured within bone sites as well as architectural features such as cortical thickness, trabecular thickness, and trabecular spacing. Furthermore, some biomarkers of cartilage health can be measured including early measures of osteoarthritis.

Downloadable data sets include metallic scaffolds.

M. Ramyar, et al. Establishing a method to measure bone structure using spectral CT. SPIE Medical Imaging, 2017. DOI: 10.1117/12.2255616. Read paper.

M. Ramyar, et al. Establishing a method to measure bone density using spectral CT. Published by the European Congress of Radiology, 2017. (Link will be made available soon).

K. Rajendran Reducing beam hardening and metal artefacts in spectral CT using Medipix3RX. Journal of Instrumentation, Vol. 9 P03015, March 2014. Read paper.

Why measure just structure or bone mineral density when you can do both?

Simultaneous measurement of both bone structure and bone composition using energy information and calcium, lipid and water channels.

A meniscus, the fibrocartilaginous cushioning in the knee joint.

This piece of cartilage shows crystal deposits (white), a sign of crystal arthropathy, a painful joint disorder.

Imaging around metal implants? No problem.

MARS Spectral imaging reduces streak and beam hardening artefacts caused by metal. This enables clear visualisation of the bone-metal interface.

Talks, presentations, and interviews

The complete list of publications by the MARS team and its research collaborators is maintained by the University of Otago Centre for Bioengineering and Nanomedicine.

  • Assoc. Prof. Steven Gieseg’s seminar at Monash University on 24/04/2017. Dr Gieseg describes his work on atherosclerotic plaque imaging and explains how the material discrimination capabilities of the MARS system can be used to identify vulnerable plaques.
  • Dr Anthony Butler, the Chief Medical Officer of MARS Bioimaging, has given a seminar at CERN on 19/05/2017, discussing the MARS team’s progress over the past several years.

  Also watch Anthony’s interview at CERN: