Evaluating the Possibility of Defining Cut-Off Points for ΔFA% in Order to Differentiate Four Major Types of Peri-Tumoral White Matter Tract Involvement

Abstract

Background:Diffusion tensor imaging (DTI) and its different scalar values such as fractional anisotropy (FA) have recently been used for evaluation of peri-tumoral white matter (WM) involvement to help define safer surgical excision margins.Objectives:The purpose of this study is to evaluate the possibility of defining diagnostic cut-off points for differentiating four major types of peri-tumoral WM involvement using FA.Patients and Methods:DTI was performed in 12 patients with high presumption of having brain tumors, on a 1.5 T MRI scanner. DTI data was processed by MedINRIA software. Two-hundred region of interests (ROI) were evaluated: 100 in the lesion zone and the rest in the normal WM in the contralateral hemisphere. FA value related to each ROI was measured, and the percentage of FA decrement (ΔFAs%) was calculated.Results:Of the 100 ROIs on the lesion side, 74 were related to high-grade lesions, 23 to low-grade ones, and three to “gliosis”. There were 54 “infiltrated”, 22 “displaced”, 15 “disrupted”, and 9 “edematous” tracts. The major type of fiber involvement, both in low-grade and high-grade tumors was “infiltrated, whereas “edematous” fibers comprised the minority. ΔFA% was more than -35 for “displaced” and “edematous” fibers, and less than -35 for the majority of “disrupted” ones, but “infiltrated” fibers had scattered distribution. Mean ΔFA% was the least for “disrupted”, followed by “infiltrated”, “edematous” and “displaced” parts.Conclusion:Introducing definite diagnostic cut-points was not possible, due to overlap. Based on the fact that “disruption” is the most aggressive process, a sensitivity analysis was carried out for “disrupted” fibers for several presumptive cut-off points.

The Assessment of White Matter Integrity Alteration Pattern in Patients with Brain Tumor Utilizing Diffusion Tensor Imaging: A Systematic Review

“…Prevalence of displacement was higher in benign tumors compared to malignant tumors. [31] Infiltration was the major pattern for HGG and LGG. Edematous comprised the minority.…”

“…In addition, edematous and disruption caused an FA decrement significantly less than displacement [23]. In a recent study, Deilami et al (2015) discovered that the percentage decrement of the FA was more than −35% for displaced and edematous fiber and less than −35% for the majority of disrupted fibers. This is in agreement with Yen et al (2009), who showed a 30% decrement; however, the paper by Yen et al (2009) included infiltration into the 0% to −30% range.…”

“…These selected papers comprised retrospective [1,7,17,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] and prospective studies [18,[36][37][38][39][40]. A total of 1163 patients ranging in age between 2 and 85 were studied in the 25 selected papers.…”

“…As described in Table 2, some of the papers discussed the cut-off point relative to the FA calculations, which is one of the parameters of DTI in the pattern of WMT alteration, which could be the indicator for classifying the pattern. Deilami et al (2015) and Yen et al (2009) studied the percentage of FA changes between the affected tract and the contralateral, unaffected hemisphere [23,31]. Yen et al (2009) showed the sole characterization of each WMT that was being assessed.…”

“…Infiltration fiber was scattered in the distribution of the cut-off by Deilami et al (2015), and similar to Wende et al (2021), infiltration fiber bundles, in terms of the FA cut-off value, should be vigilant, as 0.1 should also be considered, and it required a lower FA cut-off value [23,31,40]. Deilami et al (2015) concluded that disruption was the most presumptive cut-off point [31]. The investigation of the utilization of DTI in determining the WMT characterization pattern of its microstructure integrity in preoperative and clinical settings is summarized in Table 6.…”