Custom magnetic resonance imaging techniques for studying the human body: T1ρ imaging and magnetic resonance spectroscopy

Magnetic Resonance Imaging (MRI) utilizes nuclear spins to non-invasively produce detailed anatomical information of the human brain and body. An MRI sequence is a combination of radio waves and magnetic gradients that can manipulate these spins to produce many types of contrast, with each contrast providing unique information about the tissue being examined. Two such methods are T1ρ imaging and magnetic resonance spectroscopy (MRS).  T1ρ contrast is sensitive to the proteoglycan concentration in articular cartilage making it useful in muskuloskeletal imaging. A recent study looking at femoroacetabular impingement of the hip will be discussed, along with a proposed study looking at spinal cord compression. MRS is a valuable tool for examining metabolite concentrations in the brain. While basic MRS techniques have proven to be useful for measuring many neuronal metabolites, there are certain metabolites that are often difficult or impossible to measure reliably using common techniques. Three such metabolites that are of interest in neuropsychiatry are the neurotransmitters gamma aminobutyric acid (GABA), glycine and glutamate. Custom MRS sequences, such as MEGA-PRESS and echo-time averaging, can greatly improve the quantification of these metabolites. A study using MEGA-PRESS to look at GABA and glutamate in people taking CDP-choline to alleviate lingering symptoms while in remission of depression will be discussed.  Finally, a study will be introduced using echo-time averaging to measure glycine in people with schizophrenia.