MR-Guided Sclerotherapy of Low-Flow Vascular Malformations Using T-2-Weighted Interrupted bSSFP (T2W-iSSFP): Comparison of Pulse Sequences for Visualization and Needle Guidance

作者：Xu Di; Herzka Daniel A; Gilson Wesley D; McVeigh Elliot R; Lewin Jonathan S; Weiss Clifford R^*

来源：Journal of Magnetic Resonance Imaging, 2015, 41(2): 525-535.

DOI：10.1002/jmri.24552

• low-flow vascular malformations
• MR-guided sclerotherapy
• real-time guidance of needle placement
• T-2-weighted fat suppressed magnetic resonance imaging
• real-time MR imaging

PurposeImage-guided treatment of low-flow vascular (venous or lymphatic) malformations presents a challenging visualization problem, regardless of the imaging modality being used for guidance. The purpose of this study was to employ a new magnetic resonance imaging (MRI) sequence, T-2-weighted interrupted balanced steady-state free precession (T2W-iSSFP), for real-time image guidance of needle insertion.
Materials and MethodsT(2)W-iSSFP uses variable flip angle balanced steady-state free precession (bSSFP, a.k.a. SSFP) to establish T-2-weighting and fat suppression. Swine (n = 3) and patients (n = 4, three female, all with venous malformations) were enrolled in the assessment. T-2-weighted turbo spin echo (T-2-TSE) with spectral adiabatic inversion recovery (SPAIR), SPAIR-T-2-TSE or T-2-TSE for short, was used as the reference. T-2-weighted half Fourier acquired single shot turbo spin echo (T-2-HASTE) with SPAIR (SPAIR-T-2-HASTE, T-2-HASTE for short), fat saturated bSSFP (FS-SSFP), and T2W-iSSFP were imaged. Numeric metrics, namely, contrast-to-noise ratio (CNR) efficiency (CNR divided by the square root of acquisition time) and local sharpness (the reciprocal of edge width), were used to assess image quality. MR-guided sclerotherapy was performed on the same patients using real-time T2W-iSSFP to guide needle insertion.
ResultsComparing the visualization of needles in the images of swine, the local sharpness (mm(-1)) was: 0.21 0.06 (T-2-HASTE), 0.48 +/- 0.02 (FS-SSFP), and 0.49 +/- 0.03 (T2W-iSSFP). T2W-iSSFP is higher than T-2-HASTE (P < 0.001). For the patient images, their CNR efficiencies were: 797 +/- 66 (T-2-HASTE), 281 +/- 44 (FS-SSFP), and 860 +/- 29 (T2W-iSSFP). T2W-iSSFP is higher than FS-SSFP (P < 0.02). The frame rate of T2W-iSSFP was 2.5-3.5 frames per second. All MR-guided sclerotherapy procedures were successful, with all needles (six punctures) placed in the targets.
ConclusionT(2)W-iSSFP provides effective lesion identification and needle visualization. This new pulse sequence can be used for MR-guided sclerotherapy of low-flow vascular malformations. It may have potential use in other MR-guided procedures where heavily T-2-weighted real-time images are needed. J. Magn. Reson. Imaging 2015;41:525-535.

• 出版日期2015-2