| Part 1 Limitation of MRI plan scan in the diagnosis of BMObjective:To analyze the limitation of MRI plan scan in the diagnosis of BM.Methods:Select 64 BM and suspected BM patients to undergo routine MR examination, including MR scan and 2DE MR. Analyze the findings of BM, from the aspects of signal, site, edema and mass effect on MRI plan scan. Compare the number, size of BM between MRI plan scan and 2DE MR.Results:(1) Positive:in 64 cases,44 cases are positive and 20 cases are negative on 2 DE MR scan; 38 cases are positive and 26 cases are negative on MRI plan scan. On the basis of 2DE MR, the sensitivity of MRI plan is 86.4%, the missed diagnosis rate is 13.6%, the specificity is 76.9%. (2) Number:in 44 positive cases, MRI plan scan finds 199 lesions,2DE MR totally finds 345 lesions. On the basis of 2DE MR, the sensitivity of MRI plan is 57.7%, the missed diagnosis rate is 42.3%. (3) Size:the average size of 164 lesions measured on MRI plan is 11.32+/-0.73mm, the average size measured on 2DE MR is 12.87+/-0.78mm, There is significant difference on size between 2DE MR and MRI plan. The size measured on 2DE MR is bigger than MR plan. (4) Signal:in 199 lesions found on MRI plan, the lesions which have typical long T1 long T2 signal performance account for 44.7%, the rest 55.3% lesions are atypical signal performance. (5) Distribution:there are 55.4% lesions locate between the cortex and medulla,10.7% located in the brain surface,33.9% located in the deep brain. (6) Edema and mass effect:the lesions with severe edema around tumor account for 24.6%, the rest 75.4% lesions have no edema or only have mild-to-moderate edema. About 69.3% lesions have no mass effect, around 29.1% lesions have mild-to-moderate mass effect, only 1.5% lesions have severe mass effect.Conclusion^ 1) Positive rate of BM on 2 DE MR scanning is higher than MRI plan. (2) 2 DE MR sequence has more sensitivity than MRI plan in detecting the BM. The size measured on 2DE MR is more real, more precise; (3) The findings of BM on MRI plan have no specificity, in the aspect of signal and distribution, just half of the lesions are typical; in the aspect of edema and mass effect,only a small number of lesions have typical performance; The above results show that the MRI plan has many limitations in the diagnosis of BM. MR enhancement scanning should become a routine examination method.Part 2 Value of 3DE MR in the diagnosis of multiple BMObjective:To explore the value of 3DE MR in the diagnosis of multiple BM.Methods:Select 64 BM and suspected BM patients to undergo MR plan scan and contrast enhanced scan(2DE MR and 3DE MR). Then according to the findings of 3DE MR and the history of clinic, filter 35 multiple BM patients. Analyze and compare image quality on the two different enhancement scanning modes. At the same time, compare the number, size on these two scanning modes.Results:(1) Quality of images:The average LBR is 1.43+/-0.33, the average SNR is 21.98+/-10.1, average CNR is 7.72+/-4.45 on 3D MR. The average LBR is 1.21+/-0.22, the average SNR is 30.52+/-11.28, the average CNR is 6.63+/-4.60 on 2DE MR. There are significant difference on LBR and SNR between the two kinds of scanning modes. The LBR of 3DE MR is higher than 2DE MR. But the SNR of 2DE MR is higher than 3DE MR. There is no difference on CNR between the two types of scanning. (2) Number:in 35 cases,3DE MR scan finds 457 lesions,2DE MR finds 340 lesions. On the basis of 3DE MR, the sensitivity of 2DE MR plan is 73.5%, the missed diagnosis rate is 26.5%. (3) Size:measure the 336 lesions found by 2DE MR on 2DE MR and 3DE MR separately. The average size is about 8.87+/-0.42mm on 2DE MR and the average size is about 9.76+/-0.43mm on 3DE MR. There is significant difference on size between 2DE MR and 3DE MR. The size measured by 3DE MR is bigger than 2DE MR.Conclusion:3 DE MR is more sensitive in finding BM than 2DE MR. The number, size is displayed better than 2DE MR.3DE MR can obviously reduce missed diagnosis and misdiagnosis rate caused by 2 DE MR scan mode.3DE MR should be considered as the routine enhancement scanning way.Part 3 Value of bSSFP sequence in early diagnosis of BM:A Preliminary StudyObjective:To evaluate the value of bSSFP sequence in early diagnosis of brain metastasesMethods:Select 64 clinical patients with BM and suspected BM patients undergo MRI examination. The scan sequence includes MRI plan scan, bSSFP and 3DE MR sequence. Analyze the datas and compare the value of the 3DE MR and bSSFP in the diagnosis of early BM. Mark the differences on 3DE MR and bSSFP sequences image. Check again after three months, using the same scan sequence and parameters. Analyze datas and put focus on the differences observed by the first scan. Observe whether the differences progress.Results:In the first examination, there are 466 lesions on 3DE MR and 438 abnormal signal on bSSFP. Which of them,there are 418 lesions appearing on the two difference sequences at the same time. The 20 lesions which displayed on bSSFP sequence do not enhanced on 3DE MR. The 38 lesions displayed on 3DE MR sequence are not found on bSSFP. On the basis of 3DE MR, the sensitivity of bSSFP is 89.7%, the missed diagnosis rate is 10.3%. After three months,8 lesions are missed, the rest cases were checked again. The lesions which just observed on bSSFP are same with the first examination.Conclusion:bSSFP sequence can find some of lesions which are not displayed on 3DE MR. bSSFP has a higher sensitivity to the early small lesions. But at the same time, some lesions displayed on 3DE MR are missed on bSSFP. So bSSFP sequence cannot completely replace the enhancement scanning, can be used as a complementary sequence of 3DE MR scan sequence. |
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