Imaging or radiological tests are tools that can inform healthcare professionals of health and disease in the body.1 For example, magnetic resonance imaging (MRI) is one of the tools for visualizing, in high-resolution, the structure and function of soft tissues.2 In the case of cancer patients, MRI can be used in several different ways, such as assessing for early detection, identifying the presence of tumors, determining whether a mass is benign or malignant, assessing the degree of metastasis if any, and planning the mode of treatment (surgery or radiotherapy) required.1,3
With the rapid evolution of technology in healthcare and medicine over the years, there have been quite a few advancements in the area of imaging techniques. In fact, recent studies have shown that innovations like molecular MR can help clinicians and researchers greatly improve aspects of cancer care.4 In addition, nanotechnology has opened up new avenues in cancer treatments where a more accurate initial diagnosis and continual monitoring is feasible.5
It has also been observed that although MRI has been the imaging modality of choice in various cases (e.g., some doctors believe that breast cancer can be better distinguished from normal tissues with the help of magnetic resonance)6, a combination of two or more methods, like MRI and PET, can be employed to improve efficiency of diagnosis.7
Advances in MRI for cancer diagnosis
This is a review of the some of the latest techniques in MRI in oncology, both existing and emerging in nature.
Last year, a paper published in The Lancet elaborated on the dangerous side effects caused by TRUS-biopsy (transrectal ultrasound-guided prostate biopsy); a procedure that men with a high serum concentration of prostate-specific antigen typically have to undergo. The authors suggested that an mp-MRI could be performed as a triage test, because mp-MRI has the ability to detect higher risk diseases. MRI scans can be programmed for several different pulse sequences or parameters in order to highlight differences in normal and abnormal tissue. When two or more parameters are used, it is considered an mp-MRI. Utilizing an mp-MRI would bypass the TRUS-biopsy and possibly enhance the accuracy of diagnosis. This novel method provides information regarding tissue anatomy and characteristics such as volume and vascularity.8
In addition, doctors believe that every male person showing signs of prostate cancer should undergo an MRI as it is twice as likely to show to tumors compared to invasive biopsies such as TRUS.9
As per researchers of previous studies, MR-based molecular imaging has been demonstrated to be a non-invasive way of repetitively visualizing the biochemistry and physiology of cancer cells. This method has the potential of predicting tumor responses to specific therapies, which can consequently help identify an appropriate treatment plan for patients. So far, the outcomes of prostate, ovarian and lung cancer have “changed direction” and been bettered by way of molecular imaging. The system, in the future, can be beneficial to oncology practices, hospitals, and clinics for the detection and monitoring of cancer progression in patients.4
In the United States alone, as of 2018, it is estimated that there will be more than 250,000 new cases of invasive breast cancer diagnosed.10 It has also been concluded that metastasis is the main cause for death among such patients, therefore warranting the need for early detection in women with a high risk of breast cancer, including micrometastasis.2
Zhou, Z. et al. investigated the role of an MRI contrast agent called CREKA-Tris(Gd-DOTA)3 (Gd-DOTA (4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecyl gadolinium). It was observed that this substance binds to fibrin-fibronectin complexes (widely associated with breast cancer) present in tumors, and provides contrast enhancement in the micro- and metastatic ones. This can then be detected by molecular MRI systems for proper interventional therapies.2
Nanotechnology + MRI
The last decade or so has seen breakthroughs at the nanoscale level in areas of science and medicine. In light of that, nanotechnology-based imaging contrast agents are being developed that can particularly target tumors in vivo, with the use of traditional devices like MRI.5
Lately, there have been many interesting examples of this technology applicable to cancer research. One of these was a study by Kircher, M. F. et al. that proved the ability of triple-modality magnetic resonance imaging–photoacoustic imaging–Raman imaging nanoparticles, dubbed MPR nanoparticles, to precisely outline the margins of brain tumors. This was previously a major hurdle in providing better outcomes for patients with brain cancer.11 The MPR-nanoparticles, through an MRI, were able to track the growth of tumors and give an inside view down to individual cancer cells.
Functional MRI (fMRI)
With conventional MRI, changes in cell metabolism and tissue physiology cannot be detected. However, the development of new MRI techniques have enabled the functional assessment of structures in the body to obtain information on the different physiological processes of tumor environment. fMRI can examine factors such as oxygenation levels, cellularity, and vascularity.12 This method provides valuable and accurate data in regards to the diagnosis, staging, and response evaluation to cancer.
Diffusion-weighted MRI (DW-MRI) and perfusion or dynamic contrast-enhanced MRI (DCE-MRI) allow for a more comprehensive and qualitative analysis, and these techniques are being routinely used in association with morphologic MRI in cancer studies.7 One such research paper by the European Organization for Research and Treatment of Cancer measured the response of bone metastases in treatment with different types of MR imaging and reported excellent results.12
On the website, cancer.gov, it has been aptly mentioned that “In the fight against cancer, half of the battle is won based on its early detection.”5 With vast improvements being made to present MRI systems and the introduction of groundbreaking technologies to diagnostics, we are certainly headed towards the better management of the onset and progression of the multitude of cancers plaguing our communities.
(1) Imaging (Radiology) Tests for Cancer, 2018, American Cancer Society, https://www.cancer.org/treatment/understanding-your-diagnosis/tests/imaging-radiology-tests-for-cancer.html, (accessed 19 Aug 2018)
(2) Zhou, Z. et al. (2015), ‘MRI detection of breast cancer micrometastases with a fibronectin-targeting contrast agent’, Nature Communications, 6
(3) MRI for Cancer, 2018, American Cancer Society, https://www.cancer.org/treatment/understanding-your-diagnosis/tests/mri-for-cancer.html, (accessed 19 Aug 2018)
(4) Haris, M. et al. (2015), ‘Molecular magnetic resonance imaging in cancer’, J Transl Med, 13
(5) Early Detection & Diagnosis, 2017, NIH/National Cancer Institute: Division of Cancer Treatment & Diagnosis, https://www.cancer.gov/sites/nano/cancer-nanotechnology/detection-diagnosis, (accessed 20 Aug 2018)
(6) Breast MRI for Diagnosis and Monitoring, 2015, Breastcancer.org, https://www.breastcancer.org/symptoms/testing/types/mri/diagnosis, (accessed 20 Aug 2018)
(7) Lecouvet, F. E. et al. (2014), ‘Monitoring the response of bone metastases to treatment with Magnetic Resonance Imaging and nuclear medicine techniques: A review and position statement by the European Organisation for Research and Treatment of Cancer imaging group’, European Journal of Cancer, 50 (5), Pp 2519-2531
(8) Ahmed, H. U. et al. (2017), ‘Diagnostic accuracy of multi-parametric MRI and TRUS biopsy in prostate cancer (PROMIS): a paired validating confirmatory study’, The Lancet, 389 (10071), Pp 815-822
(9) MRI twice as likely as biopsy to spot prostate cancer, research shows, 2017, The Guardian, https://www.theguardian.com/society/2017/jan/19/mri-biopsy-prostate-cancer-diagnosis-research-nhs, (accessed 20 Aug 2018)
(10) U.S. Breast Cancer Statistics, 2018, Breastcancer.org, https://www.breastcancer.org/symptoms/understand_bc/statistics, (accessed 20 Aug 2018)
(11) Kircher, M. F. et al. (2012), ‘A brain tumor molecular imaging strategy using a new triple-modality MRI-photoacoustic-Raman nanoparticle’, Nature Medicine, 18, Pp 829-834
(12) Guimaraes, M. D. et al. (2014), ‘Functional magnetic resonance imaging in oncology: state of the art’, Radiol Bras, 47 (2), Pp 101–111