| PART1THE STUDY OF MRI FEATURES OF BRAINMETASTASESObjective: To investigate the MRI features of the brain metastases inorder to improve the accuracy of detection of brain metastases.Methods: Totally68patients with brain metastases underwentconventional MR unenhanced and enhanced scan, and the primary tumorshad been confirmed by pathology. The location, size, number, peritumoraledema, enhanced features and surrounding tissue involvement of brainmetastases were observed and recorded. The performance and detectionrates of brain metastases in all the sequences were analyzed.Results: A total of867lesions were detected in68cases. Single brainmetastases was found in19patients (19/68,27.94%), multiple metastasesin46cases (46/68,67.65%), skull metastasis in3cases (3/68,4.41%); Supratentorial foci were found in38cases (38/68,55.88%) and the mostcommon in the frontal lobes, subtentorial foci in2cases(2/68,2.94%), andcombined occurrence of supratentorial and subtentorial foci were found in25cases (25/68,36.76%).49brain metastases had peritumoral edema,56cases were with cystic degeneration and necrosis, and11cases withbleeding,22cases with meningeal metastasis. For plan scan sequences,T1WI detected165(165/867,19.38%) lesions, including36(36/165,21.82%) lesions with high signal，and the lesions were equal or low signal.The lesions were equal or high signal in T2WI, T2-FLAIR and DWI. Forenhanced scan sequences，867(867/867,100%) lesions were detected inenhanced T1WI. For the enhanced feature,541lesions were nodularenhanced,223lesions were ring enhancement,103lesions were hybridenhanced. The size of the single brain metastasis was0.50～5.77cm,average (2.43±1.48) cm, a common feature of their performance in singlebrain metastasis with other brain metastases..Conclusion: To study the MRI characteristic performance of the brainmetastaseses was conducive to the diagnosis and differential diagnosis, andcould improved the detection rate and the accuracy. PART2THE STUDY OF OPTIMIZATION OF MRI SEQUENCESFOR BRAIN METASTASESObjective: To explore the value of conventional MR sequences andthree-dimensional T1weighted imaging (3D-T1WI) sequence in diagnosisof brain metastases, and to optimize the scanning program.Methods: Totally35patients with brain metastases underwentconventional MR and unenhanced and enhanced3D-T1WI, and theprimary tumors had been confirmed by pathology. The detection rates ofbrain metastases in all the sequences were analyzed, and then the timebetween conventional and three-dimensional scanning programs werecompared.Results: A total of609lesions were detected in35cases. For planscan sequences，101(101/609,16.58%) lesions were detected in T1WI,155(155/609,25.46%) lesions in T2WI,235(235/609,38.59%) lesions inT2-FLAIR,176(176/609,28.90%) lesions in DWI (b=0),228(228/609,37.44%) lesions in3D-T1WI. For enhanced scan sequences，427(427/609,70.11%) lesions were detected in enhanced T1WI and609(609/609,100%)lesions in enhanced3D-T1WI. The diameters of547lesions were＜1.0cm,60lesions were1.0～3.0cm,2lesions were＞3.0cm, and263brain metastases had peritumoral edema. Conventional program took638s,while optimize program took575s for scanning. The detection rate of3D-T1WI plan and enhanced scans for brain metastases was significantlyhigher than those of T1WI (both P＜0.05). No significant difference ofdetection rate was found between DWI (b=0) and T2WI (P＞0.05).Conclusion: The application of3D-T1WI and enhanced MRI scansignificantly increased the detection rate in the diagnosis of brain metastases,esp ecially for the lesions which diameter＜1.0cm without edema. Toimprove the detection rate of brain metastases and save scan time,3D-T1WIcould replace conventional T1WI scans, DWI (b=0) could replace T2WI. |
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