| Objectives To explore the optimal contrast agent concentration,dose,and timing of scanning of enhanced T2 FLAIR using 3.0T MR in vitro experiments and try to apply the results to the clinic.Using high field strength MR scanner to study normal brain tissue and various craniocerebral diseases,and explore the differences between the enhanced T1 WI and enhanced T2 FLAIR in the early detection of different craniocerebral diseases,providing an important basis for the early diagnosis of diseases.Methods 1 In vitro experiments: Dimeglumine Gadopentetic Acid Injection(Guangzhou Kangchen)and Gadoleric Acid Meglumine Salt Injection(Jiangsu Hengrui)of different concentrations(4.8mmol/L,2.4mmol/L,1.2mmol/L,0.6mmol/L,0.3mmol/L,0.15mmol/L,0.075mmol/L)were injected into 14 plastic test tubes(10ml).All test tubes was placed in the center of the MR scanner head coil.All test tubes were scanned on T1 WI and T2 FLAIR.The scan level was vertical to the long axis of the test tube.The signal intensity of each test tube was measured separately,and the results were analyzed statistically.The difference was statistically significant with P<0.05.2 Clinical trials:From January 2019 to January 2020,a total of 30 patients with normal brain MR scans and enhanced scans as volunteers,including 15 males and 15 females,aged 13-76.68 patients with craniocerebral disease who underwent magnetic resonance plain scan and enhanced scan for various craniocerebral diseases and clinically or pathologically confirmed as case group.Among them,there were 14 cases of meningiomas,12 cases of metastases,7 cases of glioma and glioma postoperative review,33 cases of cerebral infarction,1 case of cerebral hemorrhage,and 1 case of schwannomas.All subjects lay supine on the scanning bed with their heads placed in the center of the coil,and performed a craniocerebral MRI scan(axial T2 WI,axial and sagittal T1 WI,axial T2 FLAIR).After injection contrast agent,the axial enhanced T1 WI was scanned.At last,scanning axial T2 FLAIR.The main evaluations were enhanced T2 FLAIR and enhanced T1 WI sequences.In the normal group,the cortical blood vessels,venous sinuses,choroid plexus,and fourth ventricular lateral crypt veins were observed and recorded on T1 WI and T2 FLAIR images.In the case group,observing and recording the enhancement of the lesion on the T1 WI and T2 FLAIR images,whether it was enhanced,the degree of enhancement,the number and extent of lesions.The results were analyzed statistically,and P <0.05 was considered statistically significant.Results 1 In vitro experiments: There was no significant difference in signal intensity between different contrast agents on T1WI(t=-0.141,P=0.892>0.05)or T2 FLAIR(t=-1.536,P=0.175>0.05).2 On T1 WI,with the reduction in concentration,the signal intensity remained at a relatively stable high level.When the contrast agent concentration was around 0.3mmol/L-0.15mmol/L,the signal intensity began to decrease,the contrast signal intensity was significantly reduced at 0.075mmol/L,.There was a difference in signal enhancement between different concentrations of contrast agents(H=35.867,P<0.001);On T2 FLAIR,with the reduction in concentration,the signal intensity gradually increased,and the signal intensity was the largest at 0.15 mmol/L,and then the signal intensity started to decrease.There were differences in signal enhancement between different concentrations of contrast agents(H=39.257,P<0.001).3 When the contrast agent concentration was 4.8mmol/L,the signal intensity of T1 WI was significantly higher than T2 FLAIR(t=73.447,P<0.001);When the contrast agent concentration was 2.4mmol/L,the signal intensity of T1 WI was significantly higher than T2 FLAIR(Z=-2.201,P=0.028<0.05).When the contrast agent concentration was 1.2mmol/L,the signal intensity of T1 WI was significantly higher than FLAIR(Z=-2.207,P=0.027<0.05);when the contrast agent concentration was 0.6 mmol/L,the signal intensity of T1 WI was higher than T2 FLAIR(Z=-2.207,P=0.027<0.05);when the contrast agent concentration was 0.3 mmol/L,there was no statistical difference in signal intensity between T1 WI and T2 FLAIR sequences(t=1.477,P=0.200>0.05);When the concentration was 0.15mmol/L,the signal intensity of T2 FLAIR was slightly higher than T1WI(Z=-2.201,P=0.028<0.05);When the contrast agent concentration was 0.075mmol/L,the signal intensity of T2 FLAIR was higher than T1WI(t=-9.163,P<0.001).4 The intraventricular choroid plexus was significantly enhanced on T1 WI,and most of them were enhanced on T2 FLAIR,the difference was no statistically significant(P=0.237>0.05),but the enhancement degree on T2 FLAIR was slightly weaker;the cortical blood vessels were all obvious on T1 WI,there was no enhancement on T2 FLAIR,and the difference was statistically significant(P<0.001);the sinuses were significantly enhanced on T1 WI,and partially enhanced on T2 FLAIR,the difference was statistically significant(P<0.001),The range was small and the degree of enhancement was weak;some of the fourth ventricular lateral crypt veins were enhanced on T1 WI and T2 FLAIR,and the difference was statistically significant(P=0.002<0.05).5 Among 14 cases of meningiomas,three patients had lesions with edge enhancement on T2 FLAIR,but no enhancement on T1 WI,it was confirmed that the microvessels on the tumor surface were abundant during and after the operation,on T1 WI and T2 FLAIR images,there was no difference in enhancement score(?2=1.929,P=0.165>0.05),most lesions could be directly identified as enhancement(P=1.000>0.05).Among the 12 metastatic tumors,11 were parenchymal metastases(26 metastases were found),and 1 was meningeal metastases.Whether T1 WI or T2 FLAIR,most of them could show metastases better,there was no difference in enhancement score(?2=0.111,P=0.739>0.05),most lesions could be directly identified as enhancement(P=1.000>0.05).Two cases of diffuse astrocytoma on T1 WI and T2 FLAIR enhancement scans showed no abnormal enhancement;one case of anaplastic astrocytoma and one case of tumor recurrence after glioma showed no differenceon of enhancement on T1 WI and T2 FLAIR;two cases after glioma operation showed no enhancement on T1 WI and T2 FLAIR;one case had meningeal enhancement at one week after surgery,and the meningeal enhancement disappeared after 1 year of review.Three patients with acute cerebral infarction-enhanced T1 WI showed brain gyrus and strip-like enhancement,However,on T2 FLAIR,it is difficult to determine whether the lesion is enhanced because of the high signal before the contrast injection.There was no enhancement of the old infarcts on T1 WI or T2 FLAIR.Conclusions 1 When the clinical need to supplement the T2 FLAIR,the scanning time should be after the T1 WI.2 The enhancement of T2 FLAIR can avoid the influence of cortical vein on T1 WI,which is beneficial to the display of meningeal and cortical lesions,it can avoid the interference of venous sinus and the display the posterior fossa lesions,it can avoid the interference of obvious enhancement of choroid plexus and facilitate the display of intraventricular lesions.3 Patients with meningioma and metastatic tumors can increase the T2 FLAIR after routine T1 WI enhancement,enhanced T2 FLAIR could be a useful complement to enhanced T1 WI.Figure13;Table 8;Reference 90... |
PDF Full Text Request