Grading of astrocytomas using the PRESTO (principles of echo-shifting with a train of observations) magnetic resonance imaging sequence

•PRESTO grading can predict the growth potential of astrocytic tumors.•No spotty signal on PRESTO is associated with low-grade glioma.•PRESTO grading is associated with the proliferation ability of astrocytic tumors. Changes in brain tissue can be detected sensitively using PRESTO (principles of echo-shifting with a train of observations) magnetic resonance imaging (MRI). The aim of this study was to evaluate the correlation between the proliferative ability of astrocytoma and intratumoral spotty signal voids seen as hypo-intense dots on PRESTO MRI. Fifty-seven astrocytic tumors, comprising 14 astrocytomas, 12 anaplastic astrocytomas, and 31 glioblastomas, were included in this retrospective study. The tumors were classified independently by blinded radiologists according to the number of spotty signal voids detected on PRESTO-MRI as follows: spot-free (grade 0), less than 3 spots (grade 1), or more than 3 spots or a large spot (grade 2). Thirteen patients (92.9%) with astrocytoma were classified as PRESTO grade 0 and 1 patient (7.1%) was classified as grade 1. Seven patients (58.3%) with anaplastic astrocytoma were classified as PRESTO grade 0, 1 (8.3%) as grade 1, and 4 as grade 2 (33.3%). Three patients (9.7%) with glioblastoma were classified as grade 0, 6 (19.4%) as grade 1, and 22 (70.9%) as grade 2. There was a strong correlation between PRESTO tumor grade and the mean MIB-1 index. These results indicate that a grading system based on the number of spotty signal voids detected on PRESTO images would be useful for the diagnosis of astrocytic tumors and predicting their proliferative ability.