Emerging research findings suggest that T2-weighted (T2w) magnetic resonance imaging (MRI) and/or T2 fluid-attenuated inversion recovery (FLAIR) MRI are significantly more useful than contrast-enhanced T1-weighted (CET1w) MRI in monitoring adult patients with diffuse glioma.
For the retrospective multicenter study, recently published in European Radiology, researchers compared CET1w MRI and T2w/T2w-FLAIR MRI in 108 patients with adult-type diffuse glioma to detect glioma progression. The cohort included 53 patients with grade 2 glioma, 21 patients with grade 3 presentations and 34 patients with grade 4 gliomas, according to the study.
The study authors detected glioma progression in 82 patients and 72 percent of the cases (59 patients) were diagnosed on CET1w and T2w/T2w-FLAIR MRI.
“We found that in almost all cases an increase in CET1w abnormalities was accompanied by an increase in T2w/T2w-FLAIR abnormalities, which raises the question of whether the routine administration of GBCA is always necessary in long-term survivors of glioma,” wrote lead study author Marcus Cakmak, MSc, who is affiliated with the Department of Radiology and Nuclear Medicine at Amsterdam University Medical Center in Amsterdam, the Netherlands, and colleagues.
For the remaining 23 cases, the researchers found that only three cases of glioma progression were based solely on CET1w MRI scans (3.7 percent). Out of the 20 cases of glioma progression identified solely with T2w/T2w-FLAIR MRI (24.4 percent), 19 patients had low-grade glioma (LGG), according to the study authors.
“These data are particularly relevant for patients with LGG, who were shown to have a substantially longer follow-up time until progression compared to patients with HGG, thus receiving many GBCA administrations during their radiological follow-up,” emphasized Cakmak and colleagues. “Once patients have remained stable for a longer period, the question of whether repeat GBCA (gadolinium-based contrast agent) administration is needed becomes particularly relevant.”
The researchers pointed out that increased abnormalities on T2w/T2w-FLAIR occurred in 44 percent of the cases involving glioma progression and were evident at a median of nearly eight months prior to detection of progression.
Three Key Takeaways
1. T2w/T2w-FLAIR MRI is more sensitive than CET1w MRI. The study found that T2w/T2w-FLAIR MRI detected glioma progression in 96.3 percent of cases, compared to 75.6 percent with CET1w MRI, suggesting that it may be more effective in monitoring glioma progression.
2. Routine GBCA administration may not always be necessary. Since T2w/T2w-FLAIR abnormalities accompanied CET1w abnormalities in almost all cases, and CET1w-only progression was rare (3.7 percent), the necessity of frequent gadolinium-based contrast agent (GBCA) use in long-term glioma survivors is questioned.
3. Particularly relevant for low-grade glioma (LGG) patients. T2w/T2w-FLAIR MRI identified glioma progression in 24.4 percent of cases where CET1w MRI failed, and most of these cases (19 out of 20) involved patients with low-grade glioma, patients who typically have longer follow-up periods and may benefit from reduced GBCA exposure.
Overall, the study authors determined that T2w/T2w-FLAIR had over a 20 percent higher detection rate for glioma progression (96.3 percent) in comparison to CET1w MRI (75.6 percent).
“Our work provides the first indication that GBCA administration may not be routinely useful in long-term survivors of glioma,” maintained Cakmak and colleagues.
(Editor’s note: For related content, see “Can Gadolinium-Free MRI Be a Viable Pre-Op Option for Differentiating Diffuse Gliomas?,” “Study: Advanced MRI Neuroimaging May Have Changed Treatment for 44 Percent of Patients with High-Grade Gliomas” and “Emerging PET Agent Gets FDA Fast Track Designation for Glioma Imaging.”)
In regard to study limitations, the authors acknowledged a degree of uncertainty with respect to the timing of tumor progression given the retrospective nature of the study. Noting that the cohort was drawn from patients undergoing follow-up maintenance for gliomas, the researchers conceded the possibility of patient selection bias. They also pointed out that corticosteroid use may have had an impact on imaging for a small number of patients at the time of tumor progression.
