Contrast-enhanced MR Imaging of Metastatic Brain Tumor at 3 Tesla: Utility of T1-weighted SPACE Compared with 2D Spin Echo and 3D Gradient Echo Sequence

Abstract

We evaluated the newly developed whole-brain, isotropic, 3-dimensional turbo spin-echo imaging with variable flip angle echo train (SPACE) for contrast-enhanced T(1)-weighted imaging in detecting brain metastases at 3 tesla (T). Twenty-two patients with suspected brain metastases underwent postcontrast study with SPACE, magnetization-prepared rapid gradient-echo (MP-RAGE), and 2-dimensional T(1)-weighted spin echo (2D-SE) imaging at 3T. We quantitatively compared SPACE, MP-RAGE, and 2D-SE images by using signal-to-noise ratios (SNRs) for gray matter (GM) and white matter (WM) and contrast-to-noise ratios (CNRs) for GM-to-WM, lesion-to-GM, and lesion-to-WM. Two blinded radiologists evaluated the detection of brain metastases by segment-by-segment analysis and continuously-distributed test. The CNR between GM and WM was significantly higher on MP-RAGE images than on SPACE images (P<0.01). The CNRs for lesion-to-GM and lesion-to-WM were significantly higher on SPACE images than on MP-RAGE images (P<0.01). There was no significant difference in each sequence in detection of brain metastases by segment-by-segment analysis and the continuously-distributed test. However, in some cases, the lesions were easier to detect in SPACE images than in other sequences, and also the vascular signals, which sometimes mimic lesions in MP-RAGE and 2D-SE images, were suppressed in SPACE images. In detection of brain metastases at 3T magnetic resonance (MR) imaging, SPACE imaging may provide an effective, alternative approach to MP-RAGE imaging for 3D T(1)-weighted imaging.

Detection of Brain Metastases by 3-Dimensional Magnetic Resonance Imaging at 3 T

“…The major advantage of imaging at 3T is the possible acquisition of high-quality isotropic 3D imaging in short scan time  due to high signal-to-noise ratio (SNR) (17,18). Another advantage is improved CNR between the enhancing lesions and background brain parenchyma on the contrast-enhanced T1-weighted images  due to suppression of signal from the normal brain parenchyma associated with prolonged T1 relaxation time and magnetization transfer effect (19,20). Superiority of 3T over 1.5T in detection of brain tumors including metastases has been reported (10).…”

“…Although the contrast-enhanced T1-weighted 3D-FSE images improve detection of brain metastases at 3T, these images have poorer gray-white matter contrast than the 3D-GRE images (17)(18)(19)(20). To alleviate this issue, some vendors have introduced T1-weighted fluid-attenuated inversion recovery (T1-FLAIR) imaging (19).…”

Volume Isotropic Simultaneous Interleaved Black- and Bright-blood Imaging: A Novel Sequence for Contrast-enhanced Screening of Brain Metastasis

“…An aggressive method is needed to detect brain metastases smaller than 10 mm because of the significantly higher rate of local control of small lesions of the brain by radiosurgery. 2 Contrast-enhanced 3-dimensional (3D) T 1 -weighted imaging based on gradient recalled echo (GRE) is widely used to detect small brain metastases 3,4 but may not allow easy differentiation of (enhanced) vessels and tumor because contrast materials remain in both blood and the tumor parenchyma. 4 To solve this problem, black-blood versions of T 1 -weighted images based on turbo spin echo (TSE) applied with the so-called motion-sensitized driven equilibrium (MSDE) pre-pulse have recently come into use.…”

“…2 Contrast-enhanced 3-dimensional (3D) T 1 -weighted imaging based on gradient recalled echo (GRE) is widely used to detect small brain metastases 3,4 but may not allow easy differentiation of (enhanced) vessels and tumor because contrast materials remain in both blood and the tumor parenchyma. 4 To solve this problem, black-blood versions of T 1 -weighted images based on turbo spin echo (TSE) applied with the so-called motion-sensitized driven equilibrium (MSDE) pre-pulse have recently come into use. 5,6 The MSDE pre-pulse comprises a series of radiofrequency (RF) pulses with 90°/ 180°/¹90°flip angles (i.e., T 2 -prep pulse) and motion-sensitization gradients that are placed symmetrically around the 180°pulse.…”

Improvement of T1 Contrast in Whole-brain Black-blood Imaging using Motion-sensitized Driven-equilibrium Prepared 3D Turbo Spin Echo (3D MSDE-TSE)

“…[1][2][3] However, differentiating enhanced vessels and tumors may be difficult because contrast agents remain in blood and tumor parenchyma. 3 To overcome this problem, blackblood T 1 -weighted 3D rapid acquisition with relaxation enhancement (RARE) (e.g., turbo spin echo [TSE]) imaging has recently come into use.…”