Improved Brain Tumor Conspicuity at 3 T Using Dark Blood, Fat-Suppressed, Dixon Unbalanced T1 Relaxation-Enhanced Steady-State MRI

Abstract

Objectives: Contrast-enhanced magnetic resonance imaging (MRI) is the cornerstone for brain tumor diagnosis and treatment planning. We have developed a novel dual-echo volumetric dark blood pulse sequence called Dixon unbalanced T1 relaxation-enhanced steady-state (uT 1 RESS) that improves the visibility of contrast-enhancing lesions while suppressing the tissue signals from blood vessels and fat. The purpose of this study was to test the hypothesis that Dixon uT 1 RESS would significantly improve the conspicuity of brain tumors compared with magnetization-prepared rapid gradient echo (MPRAGE), as well as to determine potential limitations of the technique. Materials and Methods: This retrospective study was approved by the hospital institutional review board. Forty-seven adult patients undergoing an MRI scan for a brain tumor indication were included. Contrast-enhanced MRI of the brain was performed at 3 T using both MPRAGE and Dixon uT 1 RESS. To control for any impact of contrast agent washout during the scan procedure, Dixon uT 1 RESS was acquired in approximately half the subjects immediately after MPRAGE, and in the other half immediately before MPRAGE. Image quality, artifacts, and lesion detection were scored by 3 readers, whereas lesion apparent signal-to-noise ratio and lesion-tobackground Weber contrast were calculated from region-of-interest measurements. Results: Image quality was not rated significantly different between MPRAGE and Dixon uT 1 RESS, whereas motion artifacts were slightly worse with Dixon uT 1 RESS. Comparing Dixon uT 1 RESS with MPRAGE, the respective values for mean lesion apparent signal-to-noise ratio were not significantly different (199.31 ± 99.05 vs 203.81 ± 110.23). Compared with MPRAGE, Dixon uT 1 RESS significantly increased the tumor-to-brain contrast (1.60 ± 1.18 vs 0.61 ± 0.47 when Dixon uT1RESS was acquired before MPRAGE and 1.94 ± 0.97 vs 0.82 ± 0.55 when Dixon uT 1 RESS was acquired after MPRAGE). In patients with metastatic disease, Dixon uT 1 RESS detected at least 1 enhancing brain lesion that was missed by MPRAGE on average in 24.7% of patients, whereas Dixon uT 1 RESS did not miss any lesions that were demonstrated by MPRAGE. Dixon uT 1 RESS better detected vascular and dural invasion in a small number of patients. Conclusions: In conclusion, brain tumors were significantly more conspicuous at 3 Tusing Dixon uT 1 RESS compared with MPRAGE, with an approximately 2.5-fold improvement in lesion-to-background contrast irrespective of sequence order. It outperformed MPRAGE for the detection of brain metastases, dural or vascular involvement. These results suggest that Dixon uT 1 RESS could prove to be a useful adjunct or alternative to existing neuroimaging techniques for the postcontrast evaluation of intracranial tumors.

Dark Blood Contrast‐Enhanced Brain MRI Using Echo‐uT1RESS

“…Compared with MPRAGE, single‐echo and dual‐echo Dixon versions of fid‐uT 1 RESS have been reported to provide significant improvements in tumor‐to‐brain contrast after gadolinium administration, 7,10 which was also observed in the present study. While both FISP and PSIF are gradient‐spoiled SSFP pulse sequences, a potential concern with substituting a PSIF readout for FISP is that the images will be more strongly T2 weighted due to the absence of an FID signal component 19 .…”

“…With FISP, a free induction decay (FID) signal is produced by the preceding radiofrequency (RF) excitation (along with smaller contributions from alternative signal pathways), so we will refer to this original version of the technique as fid‐uT 1 RESS . Compared with MPRAGE, fid‐uT 1 RESS significantly improves tumor conspicuity while reducing intravascular signal intensity 10 . However, the blood pool is not as dark as with T1 SPACE.…”

“…Compared with MPRAGE, fid-uT 1 RESS significantly improves tumor conspicuity while reducing intravascular signal intensity. 10 However, the blood pool is not as dark as with T1 SPACE.…”

Detection of Brain Metastases by Contrast-Enhanced MRI: Comparison of Gadopiclenol and Gadobenate in a Mouse Model

“…These factors are closely associated with neoangiogenesis, as well as the size and location of the lesions 7 . The optimization of the MRI sequences and postcontrast image processing software including artificial intelligence algorithms are also part of the detection performance, as demonstrated by recent works 8,9 . The contrast enhancement also depends on the performance of the contrast agent itself, directly linked to its relaxivity.…”

“…7 The optimization of the MRI sequences and postcontrast image processing software including artificial intelligence algorithms are also part of the detection performance, as demonstrated by recent works. 8,9 The contrast enhancement also depends on the performance of the contrast agent itself, directly linked to its relaxivity. An optimized MRI protocol including a highly sensitive contrast agent is therefore of great interest for identifying the smallest lesions as early as possible.…”