T2-mapping is becoming an important tool to detect pathological tissue; however, achieving high isotropic resolution is challenging. This work optimises a T2-prepared 3D compressed-sensing acquisition. Two T2-preparation modules (modified-BIR4, hyperbolic secant) and three Cartesian sampling trajectories (spiral, radial, VC-spiral) are explored. The NIST-ISMRM phantom and three in vivo subjects were scanned to test T2 accuracy and homogeneity. Results show more homogeneous and accurate T2 values with BIR4, due to a decreased sensitivity to B1. In vivo data showed more homogeneous T2 in WM using a radial trajectory. Based on these results, we propose an optimised 3D T2-mapping protocol of 9:48min.