When a patient is at risk for the development of certain diseases, his or her primary physician will usually monitor their medical lab testing results. If this testing shows abnormal levels of related compounds within the blood, the patient may then be recommended for a medical imaging procedure. Medical imaging tests, such as magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound (US), may show additional abnormalities or confirm the lab testing results.
MRI creates detailed images of organs and soft tissues within the patient. A super-conducting magnet is used to polarize the proton nuclei within the tissue, which emits signals that are used to generate images. The images can have different types of contrasts to help a radiologist differentiate healthy from abnormal tissue, such as cancer, multiple sclerosis and dementia.
MRI for cancer cases
Radiologists may be able to visualize tumors in certain parts of the body using MR. One common approach is to use a technique called diffusion weighted MRI (DWI).1,2 By calculating the apparent diffusion coefficient (ADC), the radiologist may be able to determine whether the tumor is benign or malignant.1 For example, the ADC of benign bone lesions may be higher than that of malignant ones. Longitudinal MR imaging studies have the potential to aid doctors in monitoring treatment options and effectiveness, especially the signal intensity changes.2
Multiple sclerosis and MRI
MRI has shown to be a valuable tool in both detection and monitoring of multiple sclerosis (MS). The diagnosis of MS is typically based upon clinical assessment, and no single biomarker can confirm the diagnosis.3
MR can provide a means to monitor a patient's possible response to treatment.3 This often reduces to monitoring the changes in the number and size of lesions apparent on MRI. According to an analysis of 31 studies, the effect of treatment on lesions over a period of 6-9 months may help to predict the effects of relapses over 12-24 months.3
MRI scans of dementia
Dementia is characterized by impaired brain function, including issues with language, learning and memory.4 In order for a patient to be diagnosed with dementia, other conditions may need to be ruled out. This is typically done using physical and neurological examinations and cognitive testing. Physicians may refer their patients with suspected clinical dementia to have an MRI of the brain.
All patients, as they age, have changes that occur in their brain. However, patients with dementia may show more signs of damage to the white matter of the brain, which can be evident in MRI. A recent study using MRI showed that the images may be able to predict dementia an average of 2.6 years before it would normally be able to detect memory loss.5 MRI may also be helpful for monitoring damage or atrophy in the tissue.
Patients with cancer, MS or dementia may benefit from MR imaging throughout the stages of disease detection, progression and treatment. Longitudinal MRI can show changes over time related to a patient's disease. As a result, physicians potentially could make more informed decisions regarding treatment options.
- Role of diffusion-weighted MRI in differentiating benign from malignant bone tumors. birpublications.org. https://www.birpublications.org/doi/full/10.1259/bjro.20180048. Last accessed November 26, 2019.
- Magnetic resonance imaging of primary malignant bone tumors. RSNA.org. https://pubs.rsna.org/doi/pdf/10.1148/radiographics.7.3.3482329. Last accessed November 26, 2019.
- MRI in the assessment and monitoring of multiple sclerosis: an update on best practice. sagepub.com. https://doi.org/10.1177/1756285617708911. Last accessed November 25, 2019.
- Dementia. RadiologyInfo.org. https://www.radiologyinfo.org/en/info.cfm?pg=dementia. Last accessed November 29, 2019.
- MRI scans shows promise in predicting dementia: Brain changes evident in scans before memory, cognitive decline. ScienceDaily.com. https://www.sciencedaily.com/releases/2018/11/181120125936.htm. Last access November 29, 2019.