MRI Findings and Their Correlation with IDH Mutational Status in Diffuse Gliomas: A Possible Poor Man's Surrogate Marker for IDH Status

Introduction: Many neurosurgeons and radiologists have noticed that IDH mutant and wild type does have certain peculiar features such as the following:

Tumor location

Cortical involvement

Surrounding/peritumoral edema

Presence of cystic features

v. The contrast enhancement pattern that correlates directly with IDH status of diffuse glioma.

In limited resource settings, these MRI features can be efficiently used as surrogate markers for the presence of IDH mutation.

Objective:

• Having discussed the significance of IDH status, what if we cannot assess it in our setups?

• In LMICs, we lack the resources to afford genetic testing and it is also not widely available and feasible.

• It is therefore prudent to look for “surrogate markers.”

Methodology:

• We retrospectively studied data of 24 patients retrieved from brain tumor database. The patient data were collected from different sources.

• We correlated their IDH status with their MRI findings.

Results:

• Cystic areas were present in only 6% of IDH-WT, while 52% IDH-MTT exhibited cystic areas.

• Necrotic areas were noted in 80% of IDH-WT and only in 18% of IDH-MT.

• Frontal tumors were more predominantly IDH-mutant 52%.

• Regarding the presence of edema, mild-moderate edema was shown in 19.8% IDH-mutant, while marked edema was seen in 70% IDH-WT.

• Contrast enhancement for IDH-MT was 24.5% (mostly <50% of the area was enhancing), while for IDH-WT it was 81.5% (with contrast enhanced area >50%).

• IDH-MT Cho/Crt was 2.1 and for IDH-WT it was 3.35.

• IDH-MT ADC <1.45 × 10−3 mm²/s vs. IDH-WT <0.81 × 10−3 mm²/s.

• These findings were statistically significant.

Conclusion:

• We suggest that MRI findings can be used as a surrogate marker for IDH status for diffuse.

• We even suggest a new category of “IDH radio” which maybe more useful than IDH NOS.

Publication History

Article published online:
15 February 2022