Article Figures & Data
Figures
- FIGURE 1.
Schematic representation of T1 signal produced by longitudinal relaxation. Proton dipoles have net magnetism in magnetic field (left) but become aligned after radiofrequency pulse (middle) and produce T1 signal on relaxation (right). B0 = magnetic field; M = magnetism; RF = radiofrequency.
- FIGURE 2.
Schematic representation of difference between T1 (top) and T2 (bottom) signal production. For T1, proton dipoles become aligned after radiofrequency pulse and produce T1 signal on relaxation. T2 signals relate to precession of proton dipoles relaxing back to ground state. FID = free induction decay; RF = radiofrequency.
- FIGURE 3.
Schematic representation of MR sequences. Spin echo uses 90° followed by 180° radiofrequency pulse to produce echo. Fast spin echo uses 90° followed by multiple 180° radiofrequency pulse to produce multiple echoes. Dual spin echo, as name suggests, produces 2 echoes from 90° followed by repeated 180° radiofrequency pulse. TE = echo time; TR = repetition time.
- FIGURE 4.
(Top) Schematic representation of GRE in which 90° radiofrequency pulse is followed by bipolar gradients first dephasing free induction decay and then rephasing free induction decay. (Bottom) Schematic representation of inversion recovery spin echo in which 180° radiofrequency pulse is followed by 90° radiofrequency pulse. RF = radiofrequency; TE = echo time; TR = repetition time.
- FIGURE 5.
Flowchart of example of PET/MRI sequence used for whole-body oncology studies. 3D = 3-dimensional; AC = attenuation correction; ax = axial; cor = coronal; DCE = dynamic contrast-enhanced; DSC = dynamic susceptibility contrast; fs = fat saturation; FSE = fast spin echo; Gd = gadolinium; IV = intravenous injection; LGE = late gadolinium enhancement; SPAIR = spectral attenuated inversion recovery; T1WI = T1-weighted imaging.
- FIGURE 6.
Flowchart of example of PET/MRI sequence used for brain studies (top) and cardiac studies (bottom). 3D = 3-dimensional; AC = attenuation correction; ax = axial; DCE = dynamic contrast-enhanced; DSC = dynamic susceptibility contrast; FSE = fast spin echo; Gd = gadolinium; IV = intravenous injection; LGE = late gadolinium enhancement; SPAIR = spectral attenuated inversion recovery; T1WI = T1-weighted imaging.
