4.2 | Spectrum characteristics
NAA showed the highest peak in 3.0T1H-MRS detection of normal brain tissue, which could reflect the functional activity and density of neurons 1. Because NAA was only stored in neurons, and the content of neurons in nasal polyps was significantly reduced, the peak value of NAA decreased significantly. Cho plays an important role in the evaluation of tumor cell metabolism. Due to the abnormal proliferation of nasal polyp cells, the cell metabolism level is high and the material exchange is strong, so the Cho summit appears to increase. Cho is a choline complex. These complex peaks include phosphatidylcholine, glycerophosphingobiline and other substances. Through these complex peaks, the specific condition of patients can be directly reflected2-3; Ace stands for acetate, the dissociated form of acetic acid, Because the pka of fatty acid carboxyl group is about 4.8, usually the pH value of plasma is 7.4, and the pH value of intracellular fluid is 7.0, so almost all the fatty acid molecules in body fluid (99.9%) are in dissociation state, that is, acetic acid exists in body fluid in the form of anion4, because of the rapid growth and obvious hyperplasia of nasal mucosa polyp, the content in polyp tissue increases significantly (this can be considered as nasal mucus) The most typical characteristic of the spectrum of membranous polyps); ace can also be produced by bacteria, It is also an important marker of anaerobe infection. Therefore, in the long-term growth process of nasal polyps, due to blocking the ostium of the sinuses or preventing the outflow of secretions from the ostium, it is easy to lead to the degeneration, necrosis or liquefaction of the inside of the sinuses or the polyps themselves due to bacterial infection, and finally form a purulent or mucopurulent abscess like substance. The creatine complex (Cr) contains creatine and phosphoric acid When the energy metabolism of creatine decreases, Cr increases, and the higher the peak value of Cr, the worse the metabolism of brain tissue; Lac is stored in the extracellular and intracellular space, mainly composed of two resonance peaks, which are also called double lines in medical circles; when TE is 288, the double peaks are upward, when TE is 144, the double peaks are downward1-7. In the healthy state, cells are mainly aerobic metabolism, Lac peak is trace or none; the growth block of nasal polyp tissue has an inhibitory effect on cell aerobic respiration, and glycolysis will be strengthened, so Lac peak is increased6-10. The degree of necrosis and degeneration of nasal polyps was in direct proportion to the decrease of NAA and the increase of Cho. Ace, Cho, Lac, NAA are highly specific in the diagnosis of nasal polyps. The peak of Ace is significantly higher (which can be considered as the most typical feature of the spectrum of nasal polyps), Cho is higher, Lac is higher, Lac / Ace ratio is significantly lower, Cho / NAA ratio is significantly higher, Lac / NAA ratio is higher, which provides an objective basis for the diagnosis of nasal polyps.
In a word, on the basis of other imaging examination, the spectrum analysis of 3.0T1H-MRS can get the biochemical metabolism information of clinical value of nasal mucosa polyp.
The value of Ace in nasal polyps was“11.43 ± 6.11”, NAA (17.76 ± 6.20), Cho (23.19 ± 6.91), Lac (12.51 ± 3.42), Lac / Ace (1.09 ± 0.56); Cho / NAA (1.34 ± 1.10), Lac / NAA (0.70 ± 0.55). According to the different characteristics of Cho, Cr, Lac, Ace peak integral value and the ratio of each integral value, it is helpful for the correct diagnosis of nasal mucosa polyp.