Quantitative Diagnosis And Analysis Of Arachnoid Cysts In Cisterna Magna By Low B Value DWI Of Magnetic Resonance

Objective:To study the value of low b value DWI sequence of magnetic resonance quantitative analysis of arachnoid cysts in cisterna magna.Methods:Prospective analysis of clinical and imaging data of cases of lesions in cistern magna in Yuxi City People’s Hospital of the Sixth Affiliated Hospital of Kunming Medical University from September 2020 to December 2020.A total of 46 patients with lesions in cistern magna underwent examination.Both routine cranial MRI,PC cine MRI(Phase-contrast cine MRI)and high and low b-value(1000、100 s/mm2)DWI examinations were performed.The Q-FLOW analysis software was used to quantitatively analyze the average velocity-time curve of the lesion,the prepontic cistern,and the adjacent cerebellar parenchyma within a cardiac cycle to diagnose whether the lesion is a cisterna magna arachnoid cyst.The high and low b value DWI sequence scan data are automatically reconstructed by the post-processing software to obtain the ADC maps,which are ADC 1000 map and ADC 100 map,respectively.Observe the ADC image with the naked eye,and define it as high,equal,or low signal based on the comparison of the signal intensity of the lesion in cisterna magna with the signal intensity of the cerebellar parenchyma or the cerebrospinal fluid of the pontine cistern.Combined with the axial T2WI,DWI,ADC image and PC cine MRI performance,the ADC image reconstructed in the two groups of b value(b value=1000、100 s/mm2)area(arachnoid cyst in cisterna magna,widened cisterna magna,Prepontic cistern,adjacent cerebellar parenchyma)are pre-defined,ROI is selected in each pre-defined area,and ADC value is measured.The ADC value of arachnoid cyst in cistern major is ADCAC;the prepontic cistern is ADCP,and the adjacent cerebellar parenchyma is ADCc.The SPSS23.0 software is used for statistical analysis.The ADC value between the low b value 100 s/mm2 and the high b value 1000 s/mm2 was compared by using t-test.It was statistically significant when P<0.05.Results:①A total of 46 patients with cisterna magna lesions were examined:45 patients were diagnosed as the cisterna magna arachnoid cysts,31 were males and 14 were females,males were(49.7±15.2)years old;females(47.4 ± 13.7)years old,a total of 60 cisterna magna arachnoid cysts;another patient was diagnosed as the mega cisterna magna,,a female,80 years old.②The average velocity time curve of 86.67%cisterna magna arachnoid cysts in one cardiac cycle showed serrated waveform.Another 13.33%of cysts showed sinusoidal or nearly sinusoidal curves.100%of the anterior cistern curves were sinusoidal or approximately sinusoidal.The curve of 100%adjacent cerebellar parenchyma was zigzag.③Arachnoid cyst in cisterna magna shows a low signal on the b=100 s/mm2 ADC map,a high signal on the b=1000 s/mm2 ADC map,which was similar to the signal of the prepontic cistern;There is no obvious difference in the ADC map of the two b values,that is,the prepontic cistern shows high signal on both high and low b value ADC maps,and the adjacent cerebellar parenchyma shows low signal on both high and low b value ADC maps.④The ADC values of arachnoid cyst in cistern major,prepontic cistern,and adjacent cerebellar parenchyma in the b=100 s/mm2 group were(3.08±0.18)×10-3mm2/s、(23.95±3.12)× 10-3mm2/s、(1.02±0.23)× 10-3mm2/s;in the b=1000 s/mm2 group were(2.99±0.08)× 10-3mm2/s、(2.96±0.28)×10-3mm2/s、(0.67±0.04)±10-3mm2/s;The difference between the high and low b-values of each predefined area was statistically significant(P<0.001).⑤The average value of ADC100AC was compared with the average value of ADC100p and ADC 100C,and the difference was statistically significant(P<0.001);Pairwise comparison between the mean value of ADC1000AC and ADC1000P,the difference was not statistically significant(P>0.05);pairwise comparison between the mean value of ADC1000AC and the mean value of ADC 1000c,the difference was statistically significant(P<0.001).⑥The values of ADC100P/AC and ADC 1 000P/AC were 7.81 ± 1.08、0.33±0.07,and the difference between pairwise comparisons was statistically significant(P<0.001);the mean values of ADC 100C/AC and ADC 1000C/AC were 0.99±0.10、0.22±0.01,the difference between pairwise comparison was statistically significant(P<0.001).Conclusion(s):Low b value DWI sequence of magnetic resonance can be used as a new functional magnetic resonance imaging method to diagnose arachnoid cyst of cistern magnum occipitum quickly and accurately,which has clinical practical value.