Figure 3

(A) T1-weighted fat-suppressed MR imaging without contrast; and MR imaging after contrast in (B) arterial phase, (C) portal phase, and (D) late phase. In T1-weighted images without contrast, the signal in the periphery of the mass (arrow) is similar to the muscle signal; the center of the lesion clearly shows a hypointense signal (*). Although impregnation of both components began in the arterial phase, the peripheral region (arrow) showed a stronger signal during the arterial and portal phases, followed by signal decay in the late phase due to relatively rapid washout, indicative of hypervascularization. The enhancement of the central component is far more intense in the late phase (*), probably due to a large interstitial space and slow flow through the vascular components.