ABSTRACT
Purpose To explore the application value of dynamic contrast enhanced MRI (DCE-MRI) in judging and diagnosing metastasis of lung cancer.Material and Methods Sixty-one metastatic spinal tumor patients received DCE-MRI and their images acquired after scanning were post-processed.Signal intensity-time curve,signal intensity amplification in rising period of the curve (Peak SE％),maximum ascending linear slope of the curve (Max Wash-in SE％) and descending slope of the curve (Wash-out SE％) and other semiquantitative parameters were acquired.Double chamber pharmacokinetics was adopted to analyze and obtain Ktrans,rate constant (Kep) and other quantitative parameters.CHAID method was taken to establish tree structure model to confirm optimal sorting parameter and identify optimal division.Results For the DCE-MRI scanning parameters for 61 metastatic spinal tumor patients,differences of Wash-out SE％ and Kep between lung cancer and other tumor spinal metastasis were statistically significant (P＜0.01),while differences of Peak SE％,Max Wash-in SE％ and Ktrans between the two were not statistically significant (P＞0.05).When Wash-out SE％＞-660.6％ and Max Wash-in SE％＞98.0％,original focus of about 94.7％ was possible to come from lung.When taking tree structure model set up in the study for identification,10-fold cross-validation indicated (29.5±5.8)％ error rate.Conclusion Taking DCE-MRI semi-quantitative and quantitative analysis parameters for identification and diagnosis of metastasis of lung cancer is feasible.It can provide reference evidence for source identification of spinal sarcoma and clinical treatment.
ABSTRACT
BACKGROUND: Our study was performed to evaluate the image quality of 3 T MR wrist arthrograms with attention to ulnar wrist structures, comparing image quality of isotropic 3D proton density fat suppressed turbo spin echo (PDFS TSE) sequence versus standard 2D 3 T sequences as well as comparison with 1.5 T MR arthrograms. METHODS: Eleven consecutive 3 T MR wrist arthrograms were performed and the following sequences evaluated: 3D isotropic PDFS, repetition time/echo time (TR/TE) 1400/28.3 ms, voxel size 0.35x0.35x0.35 mm, acquisition time 5 min; 2D coronal sequences with slice thickness 2 mm: T1 fat suppressed turbo spin echo (T1FS TSE) (TR/TE 600/20 ms); proton density (PD) TSE (TR/TE 3499/27 ms). A 1.5 T group of 18 studies with standard sequences were evaluated for comparison. All MR imaging followed fluoroscopically guided intra-articular injection of dilute gadolinium contrast. Qualitative assessment related to delineation of anatomic structures between 1.5 T and 3 T MR arthrograms was carried out using Mann-Whitney test and the differences in delineation of anatomic structures among each sequence in 3 T group were analyzed with Wilcoxon signed-rank test. Quantitative assessment of mean relative signal intensity (SI) and relative contrast measurements was performed using Wilcoxon signed-rank test. RESULTS: Mean qualitative scores for 3 T sequences were significantly higher than 1.5 T (p < 0.01), with isotropic 3D PDFS sequence having highest mean qualitative scores (p < 0.05). Quantitative analysis demonstrated no significant difference in relative signal intensity among the 3 T sequences. Significant differences were found in relative contrast between fluid-bone and fluid-fat comparing 3D and 2D PDFS (p < 0.01). CONCLUSIONS: 3D isotropic PDFS sequence showed promise in both qualitative and quantitative assessment, suggesting this may be useful for MR wrist arthrograms at 3 T. Primary reasons for diagnostic potential include the ability to make reformations in any obliquity to follow the components of ulnar side wrist structures including triangular fibrocartilage complex. Additionally, isotropic imaging provides thinner slice thickness with less partial volume averaging allowing for identification of subtle injuries.
