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| Item Type: | Article |
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| Title: | Fractal dimension of high-risk neuroblastoma vascularity in MRI is associated with chemotherapy response and event-free survival |
| Creators Name: | Michallek, Florian, Dewey, Marc, Hero, Barbara, Hauptmann, Kathrin, Veldhoen, Simon, Paulsen, Verena, Astrahantseff, Kathy, Deubzer, Hedwig E., Simon, Thorsten, Eggert, Angelika and Thole-Kliesch, Theresa M. |
| Abstract: | PURPOSE: To assess therapeutic and prognostic implications of perfusion characterization by fractal analysis using routine MRI in high-risk primary neuroblastomas and to establish a pathophysiologic connection between vascularity phenotype, perfusion imaging characteristics, and treatment response. MATERIALS AND METHODS: In a retrospective cohort study across 30 centers, MRI data of patients with high-risk neuroblastoma (June 2005–February 2021) were collected at the time point of diagnosis (TP1) and after induction chemotherapy before surgery (TP2), with data split into separate discovery (single-center) and validation cohorts (29 centers). Fractal analysis was performed on contrast-enhanced, fat-saturated, T1-weighted sequences at both time points to obtain voxel-wise local fractal dimension (FD) maps for predicting volumetric tumor response. The association of global FD with event-free survival (EFS) was assessed using a Cox proportional hazards model. Additionally, FD was calculated from CD34-stained endothelium in selected histologic tumor samples. Accuracy of response prediction, prognostic value for EFS, and correlation between FD of immunohistochemical vascularity and MRI-derived perfusion were also evaluated. RESULTS: In 73 patients (median age, 3 years [IQR, 3]; 39 male patients; discovery cohort, n = 36; validation cohort, n = 37), local FD maps helped predict volumetric tumor response to induction chemotherapy between TP1 and TP2 with good accuracy (root mean squared error, 47.78 mL; R(2) = 0.94; P < .001), visualizing intratumor high perfusion complexity in areas with low response potential. In multivariate Cox proportional hazards modeling, MYCN status (hazard ratio, 2.30; 95% CI: 1.16, 4.55; P = .017) and global FD at TP2 (hazard ratio, 0.65; 95% CI: 0.47, 0.88; P = .006) were significantly associated with EFS. Complexity of both CD34-immunohistochemical microvascularity (1.23 ± 0.09 [SD] to 1.44 ± 0.07, P < .001) and MRI perfusion (3.40 ± 0.04 to 3.53 ± 0.07, P < .001) increased throughout induction chemotherapy. CONCLUSION: Fractal analysis of MRI-derived perfusion complexity was associated with spatial heterogeneity of chemotherapy response and stratified prognosis in MYCN nonamplified high-risk neuroblastoma, supporting its potential as an imaging biomarker linked to microvascular architecture. |
| Keywords: | Pediatrics, MR-Imaging, Nervous-Peripheral, Fractal Analysis, Tissue Characterization, Tumor Response |
| Source: | Radiology: Imaging Cancer |
| ISSN: | 2638-616X |
| Publisher: | Radiological Society of North America |
| Volume: | 8 |
| Number: | 1 |
| Page Range: | e250070 |
| Date: | 1 January 2026 |
| Official Publication: | https://doi.org/10.1148/rycan.250070 |
| PubMed: | View item in PubMed |
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