Bell Jonathan B, Sheriff Sulaiman, Goryawala Mohammed Z, Cullison Kaylie, Azzam Gregory A, Meshman Jessica, Abramowitz Matthew C, Ivan Michael E, de la Fuente Macarena I, Mellon Eric A
Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, 1475 NW 12th Ave, Miami, FL, 33136, USA.
Department of Radiology, Miller School of Medicine, University of Miami, Miami, FL, USA.
Radiat Oncol. 2025 May 22;20(1):86. doi: 10.1186/s13014-025-02666-z.
Outcomes in glioblastoma are improved by surgical resection and adjuvant radiation (RT). In primary GBM (pGBM), large clinical target volume (CTV) margins typically cover occult invasion. In recurrent GBM (rGBM), RT often uses tiny CTV margins that likely omit occult invasion due to re-RT radiation necrosis concerns. Whole-brain spectroscopic MRI (sMRI) is an emerging technique with similar resolution to PET that may help define the CTV for rGBM.
Patients with pGBM (n = 18) and rGBM (n = 19) underwent sMRI with RT simulation. T1-post contrast (T1PC) and T2/FLAIR MRI volumes were contoured. sMRI generated choline/N-acetylaspartate > 2x (Cho/NAA > 2x) volumes are known to correlate with high-risk invasion. Hausdorff distances were calculated to define the margin necessary to cover Cho/NAA > 2x in pGBM and rGBM. In rGBM, mock CTV expansions from T1PC volumes were created to determine non-selective CTV expansion sizes needed to cover Cho/NAA > 2x volumes.
For pGBM, the median T1PC, Cho/NAA > 2x, and T2/FLAIR volumes were 32.3 cc, 45.0 cc, and 74.8 cc respectively. For rGBM, the median T1PC, Cho/NAA > 2x, and T2/FLAIR volumes were 21.7 cc, 58.9 cc, and 118.3 cc, respectively. T2/FLAIR volumes increased more relative to T1PC volumes in rGBM than pGBM (p ≤ 0.001). Meanwhile, the median Hausdorff distance between T1PC and Cho/NAA > 2x was 22.9 mm in pGBM and 25.7 mm in rGBM, suggesting that the high-risk volume does not significantly change. In rGBM, it is common to use no CTV expansion from the T1PC volume which only included 61% of high-risk Cho/NAA > 2x volume. Conversely, T1PC expansions of 10-, 15-, and 20-mm covered 87%, 94%, and 98% of Cho/NAA > 2x volume.
sMRI Cho/NAA > 2x delineates high-risk occult disease in glioblastoma and extends beyond T1PC MRI borders. Typical large CTV expansions in pGBM mostly include Cho/NAA > 2x volumes. However, small CTV expansions commonly used in rGBM poorly cover Cho/NAA > 2x, suggesting that larger CTV expansions or Cho/NAA > 2x guidance may be of benefit.
手术切除和辅助放疗（RT）可改善胶质母细胞瘤的预后。在原发性胶质母细胞瘤（pGBM）中，较大的临床靶体积（CTV）边界通常覆盖隐匿性浸润。在复发性胶质母细胞瘤（rGBM）中，由于再次放疗导致放射性坏死的担忧，放疗通常使用很小的CTV边界，这可能会遗漏隐匿性浸润。全脑磁共振波谱成像（sMRI）是一种新兴技术，其分辨率与PET相似，可能有助于确定rGBM的CTV。
pGBM患者（n = 18）和rGBM患者（n = 19）接受了带有放疗模拟的sMRI检查。对T1加权增强（T1PC）和T2/液体衰减反转恢复（FLAIR）磁共振成像体积进行了轮廓勾画。已知sMRI生成的胆碱/ N - 乙酰天门冬氨酸> 2倍（Cho/NAA > 2倍）的体积与高风险浸润相关。计算豪斯多夫距离以确定在pGBM和rGBM中覆盖Cho/NAA > 2倍所需的边界。在rGBM中，从T1PC体积创建模拟CTV扩展，以确定覆盖Cho/NAA > 2倍体积所需的非选择性CTV扩展大小。
对于pGBM，T1PC、Cho/NAA > 2倍和T2/FLAIR体积的中位数分别为32.3立方厘米、45.0立方厘米和74.8立方厘米。对于rGBM，T1PC、Cho/NAA > 2倍和T2/FLAIR体积的中位数分别为21.7立方厘米、58.9立方厘米和118.3立方厘米。与pGBM相比，rGBM中T2/FLAIR体积相对于T1PC体积增加得更多（p≤0.001）。同时，pGBM中T1PC与Cho/NAA > 2倍之间的豪斯多夫距离中位数为22.9毫米，rGBM中为25.7毫米，表明高风险体积没有显著变化。在rGBM中，通常不从仅包含61%高风险Cho/NAA > 2倍体积的T1PC体积进行CTV扩展。相反，10毫米、15毫米和20毫米的T1PC扩展分别覆盖了87%、94%和98%的Cho/NAA > 2倍体积。
sMRI的Cho/NAA > 2倍可描绘胶质母细胞瘤中的高风险隐匿性疾病，且超出T1PC磁共振成像边界。pGBM中典型的大CTV扩展大多包括Cho/NAA > 2倍体积。然而，rGBM中常用的小CTV扩展对Cho/NAA > 2倍的覆盖较差，这表明更大的CTV扩展或Cho/NAA > 2倍引导可能有益。
