Magnetic Resonance Spectroscopy (MRS) Imaging for Hypoxic-Ischemic Encephalopathy (HIE)
MRI helps look at the anatomical structure of the brain in thin ‘slices,’ which reveals anatomical/structural abnormalities and changes (like growth, necrosis, atrophy, or inflammation), even if it is deep inside the brain. MRI can be done with or without contrast, which can help highlight certain structural features that may be diagnostically useful. MRS looks at the metabolic changes occurring within the human body, looking at the concentrations of such biochemicals as NAA, choline, creatine, lipids, myo-inositol, lactate, glutamate, GABA, and other important molecules based on their unique physical properties. This is done in conjunction with MRI to provide a more detailed picture of a specific diagnosis.
Many people know what magnetic resonance imaging (MRI) studies are and have had one before. MRI provides a clear picture of the structures of the human body, and is often used to help diagnose neurological abnormalities, especially for the diagnosis of hypoxic ischemic encephalopathy (HIE), seizure disorders and other conditions that stem from the brain.
A new and complementary imaging technique called Magnetic Resonance Spectroscopy (MRS) (also referred to as MR spectroscopy) is now being adopted in conjunction with MRI, helping researchers and medical practitioners understand not just the structure of a particular tissue, but also the metabolites in that tissue – effectively, it allows practitioners to understand the substances that have accumulated in a particular tissue noninvasively, without having to take a biopsy.
The process is used most commonly to investigate diseases like cancer, epilepsy, Alzheimer’s Disease and Parkinson’s Disease, among others. It allows physicians to see important details, like whether there is/are:
- A loss or decrease in neuronal tissue
- Aggressive/malignant tumors
- Tissue or major cell death due to injury
disease, or lack of blood supply
- Cranio-cerebral trauma
- Gycolysis in a tissue, which can indicate ischemia, hypoxia, or other pathologies
- Certain specific types of encephalopathy (brain abnormalities)
In the case of hypoxic-ischemic encephalopathy (HIE), MRS can be used to determine lactate levels. When the brain doesn’t get enough blood or oxygen flow, tissues try to switch from aerobic metabolism to anaerobic glycolysis. This causes a biochemical called lactate to accumulate in the tissues. We know that markedly elevated lactate is a key feature in spectroscopic analyses of cerebral hypoxia/ischemia. Research has also indicated that in cerebral hypoxia/ischemia, choline levels are elevated and NAA and creatine levels are lowered. Lipid levels can also increase in the case of fetal stroke.
MR spectroscopy can also be sometimes used with head injury to assess the degree of neuronal injury and predict patient outcomes. In the case of diffuse neuronal injury, imaging sometimes underestimates brain damage levels, and MRS can help more accurate assess damage by taking into account a clinical item called the NAA/Cr ratio. Lactate and lipid presences also indicate more severe outcomes.
MRI and MRS are very different techniques that measure very different things but are highly complementary and can be used to help guide a patient’s treatment and understand the underlying causes of a condition and potential prognoses. These studies are interpreted by a trained radiologist.
Learn More About Magnetic Resonance Spectroscopy:
- What’s the Difference Between MRI and MRS?
- Mayfield Clinic: What Can Patients Expect from Magnetic Resonance Spectroscopy Testing?
- [Radiopaedia] The Physics of MRS
- NeuroWeb: Fundamentals of MR Spectroscopy
- American Society of Functional Neuroradiology: MRS Overview and Brain Metabolites
- Current Research in MRS
The information presented above is intended only to be a general educational resource, and is not intended to be (and should not be interpreted as) medical advice. If you have questions about recent MRI or MRS results, please consult with a medical professional.