title: Comparison of accelerated 3-D spiral chemical shift imaging and single-voxel spectroscopy at 3T in the pediatric age group.
abstract: Single-voxel spectroscopy (SVS) is usually used in the pediatric population when a short acquisition time is crucial. To overcome the long acquisition time of 3-D phase-encoded chemical shift imaging (CSI) and lack of spatial coverage of single-voxel spectroscopy, efficient encoding schemes using spiral k-space trajectories have been successfully deployed, enabling acquisition of volumetric CSI in <5 min. We assessed feasibility of using 3-D spiral CSI sequence routinely in pediatric clinical settings by comparing its reconstructed spectra against SVS spectra. Volumetric spiral CSI obtained spectra from 2-cc isotropic voxels over a 16×16×10-cm region. SVS acquisition encoded a 3.4-cc (1.5-mm) isotropic voxel. Acquisition time was 3 min for every technique. Data were gathered prospectively from 11 random pediatric patients. Spectra from left basal ganglia were obtained using both techniques and were processed with post-processing software. The following metabolite ratios were calculated: N-acetylaspartate/creatine (NAA/Cr), choline/creatine (Cho/Cr), lactate/creatine (Lac/Cr) and N-acetylapartate/choline (NAA/Cho). We collected data on 11 children ages 4 days to 10 years. In 10/11 cases, spectral quality of both methods was acceptable. Considering 10/11 cases, we found a statistically significant difference between SVS and 3-D spiral CSI for all three ratios. However, this difference was fixed and was probably caused by a fixed bias. This means that 3-D spiral CSI can be used instead of SVS by removing the mean difference between the methods for each ratio. Accelerated 3-D CSI is feasible in pediatric patients and can potentially substitute for SVS.
authors.affiliation: Department of Radiology, Boston Children's Hospital and Harvard Medical School, 300 Longwood Ave., Boston, MA, 02115, USA, sandrineyazbek@gmail.com.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Yazbek
authors.forename: Sanjay P
authors.initials: SP
authors.lastname: Prabhu
authors.forename: Pauline
authors.initials: P
authors.lastname: Connaughton
authors.forename: Patricia E
authors.initials: PE
authors.lastname: Grant
authors.forename: Borjan
authors.initials: B
authors.lastname: Gagoski
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D057054:Molecular Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers
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