MR SPECTROSCOPY

Q.All are true regarding MRS except

a. The acquisition of long echo time data  allows the detection of N-acetylaspartate (NAA), creatine (Cr/PCr) and choline (Cho) in normal brain

b. The methyl resonance of NAA produces a large sharp peak at 2.01 p.p.m

c.choline  produce resonance at 3.22 p.p.m

d. The acquisition of long echo time data  provides spectra with better signal to noise

e. The acquisition of short echo time data provides myo-inositol, glutamate and glutamine

ANS.---d

The acquisition of long echo time data (TE = 270 ms, TR = 3 ms) allows the detection of N-acetylaspartate (NAA), creatine (Cr/PCr) and choline (Cho) in normal brain, and lactate in areas of abnormality. The methyl resonance of NAA produces a large sharp peak at 2.01 p.p.m. and acts as a neuronal marker as it is almost exclusively found in neurons in the human brain, where it is found predominantly in the axons and nerve processes. The creatine peak (3.03 p.p.m.) arises from both phosphocreatine- and creatine-containing substances in the cell and choline (3.22 p.p.m) is thought to arise from choline-containing substances in the cell membrane.

The acquisition of short echo time data (TE = 30 ms, TR = 2s) has become the standard spectroscopy sequence and has the advantage of reduced effects from T2 losses and therefore provides spectra with better signal to noise. In addition, it detects additional resonances from metabolites with complex MR spectra such as myo-inositol, glutamate and glutamine .