'Low grade glioma': an update for radiologists

Abstract

With the recent publication of a new World Health Organization brain tumour classification that reflects increased understanding of glioma tumour genetics, there is a need for radiologists to understand the changes and their implications for patient management. There has also been an increasing trend for adopting earlier, more aggressive surgical approaches to low-grade glioma (LGG) treatment. We will summarize these changes, give some context to the increased role of tumour genetics and discuss the associated implications of their adoption for radiologists. We will discuss the earlier and more radical surgical resection of LGG and what it means for patients undergoing imaging.

Figure 1.

An axial fluid attenuation inversion-recovery image with gadolinium showing the contour around the tumour margin used to calculate tumour volume. The overall tumour volume is the product of the contoured areas on each axial slice, the slice thickness and interslice gap. A, anterior; I, inferior; L, left; P, posterior; R, right; S, superior.

Figure 2.

A flow diagram of the new diffuse glioma classification system adapted from Louis et al. The 2016 World Health Organization Classification of Tumors of the Central Nervous System: a summary. Acta Neuropathol 2016; 131: 803–20. ATRX, alpha thalassaemia/mental retardation syndrome X-linked; IDH, isocitrate dehydrogenase; NOS, not otherwise specified; TP53, tumour protein 53.