Aims: To implement a multislice two-dimensional (2D) T2-weighted sequence suitable for subvoxel image registration and to assess its usefulness in detecting change in high-grade intracranial gliomas.
Materials and methods: Twenty patients with high-grade gliomas were studied on two or more occasions. T2-weighted multislice pulse sequences with a Gaussian slice profile, 50% overlapping slices and nearly isotropic voxels were acquired. The images were registered and subtraction images were produced. The images were compared with three-dimensional (3D) T1-weighted registered images and conventional unregistered T2-weighted images. All images were scored for changes in the lesions and ventricular system.
Results: The 2D and 3D registered subtraction images were the most sensitive for detecting changes in both the lesions and other regions in the brain. The mean rank scores were significantly higher for the lesions (chi2=86.742; df=5, n=38, P<0.0001) and for the ventricles (chi2=63.837; df=5, n=35, P<0.0001) compared with the unregistered and registered anatomical images. The subtraction images were also most sensitive for detecting signal intensity changes irrespective of the direction of change.
Conclusion: Rigid body subvoxel registration can be successfully performed with both multislice 2D and 3D imaging. In principle, virtually all forms of clinical MR images of the brain can be accurately registered and subtracted.