Cullison Kaylie, Samimi Kayla, Bell Jonathan B, Maziero Danilo, Valderrama Alessandro, Breto Adrian L, Jones Kolton, De La Fuente Macarena I, Kubicek Gregory, Meshman Jessica, Azzam Gregory A, Ford John C, Stoyanova Radka, Mellon Eric A
Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida; Department of Biomedical Engineering, University of Miami, Coral Gables, Florida; Medical Scientist Training Program, University of Miami Miller School of Medicine, Miami, Florida.
Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida.
Int J Radiat Oncol Biol Phys. 2024 Sep 30. doi: 10.1016/j.ijrobp.2024.09.028.
Glioblastoma changes during chemoradiation therapy are inferred from magnetic resonance imaging (MRI) before and after treatment but are rarely investigated due to logistics of frequent MRI. Using a combination MRI-linear accelerator (MRI-linac), we evaluated changes during daily chemoradiation therapy.
Patients with glioblastoma were prospectively imaged daily during chemoradiation therapy on 0.35T MRI-linac and at 3 timepoints with and without contrast on standalone high-field MRI. Tumor or edema (lesion) and resection cavity dynamics throughout treatment were analyzed and compared with standalone T1 postcontrast (T1+C) and T2 volumes.
Of 36 patients included in this analysis, 8 had cavity only, 12 had lesion only, and 16 had both cavity and lesion. Of these, 64% had lesion growth and 46% had cavity shrinkage during treatment on MRI-linac scans. The average MRI-linac migration distance was 1.3 cm (range, 0-4.1 cm) for lesion and 0.6 cm (range, 0.1-2.1 cm) for cavity. Standalone versus MRI-linac volumes correlated strongly with R values: 0.991 (T2 vs MRI-linac cavity), 0.972 (T1+C vs MRI-linac cavity), and 0.973 (T2 vs MRI-linac lesion). There was a moderate correlation between T1+C and MRI-linac lesion (R = 0.609), despite noncontrast MRI-linac inability to separate contrast enhancement from surrounding nonenhancing tumor and edema. From pretreatment to posttreatment in patients with all available scans (n = 35), T1+C and MRI-linac lesions changed together-shrank (n = 6), grew (n = 12), or unchanged (n = 8)-in 26 (74%) patients. Another 9 patients (26%) had growth on MRI-linac, although the T1+C component shrank. In no patient did T1+C lesion grow while MRI-linac lesion shrank.
Anatomic changes are seen in patients with glioblastoma imaged daily on MRI-linac throughout the chemoradiation therapy course. As surgical resection cavities shrink, margins may be reduced to save normal brain. Patients with unresected or growing lesions may require margin expansions to cover changes. Limited volume glioblastoma boost trials could consider triggered gadolinium contrast administration for evaluation of adaptive radiation therapy when lesion growth is seen on noncontrast MRI-linac.
胶质母细胞瘤在放化疗期间的变化可通过治疗前后的磁共振成像（MRI）推断，但由于频繁进行MRI检查的实际困难，相关研究较少。我们使用MRI直线加速器（MRI-linac）组合设备，评估了每日放化疗期间的变化情况。
胶质母细胞瘤患者在0.35T MRI-linac上进行放化疗期间每天进行前瞻性成像，并在3个时间点在独立的高场MRI上进行有对比剂和无对比剂成像。分析整个治疗过程中肿瘤或水肿（病变）及切除腔的动态变化，并与独立的T1加权增强扫描（T1+C）和T2加权像体积进行比较。
本分析纳入的36例患者中，8例仅有腔隙，12例仅有病变，16例既有腔隙又有病变。其中，在MRI-linac扫描中，64%的患者病变有生长，46%的患者腔隙有缩小。病变在MRI-linac上的平均迁移距离为1.3 cm（范围0 - 4.1 cm），腔隙为0.6 cm（范围0.1 - 2.1 cm）。独立MRI与MRI-linac的体积与R值有很强的相关性：0.991（T2与MRI-linac腔隙）、0.972（T1+C与MRI-linac腔隙）和0.973（T2与MRI-linac病变）。T1+C与MRI-linac病变之间存在中度相关性（R = 0.609），尽管无对比剂的MRI-linac无法将对比增强与周围未增强的肿瘤和水肿区分开来。在所有有可用扫描的患者（n = 35）中，从治疗前到治疗后，T1+C和MRI-linac病变在26例（74%）患者中一起变化——缩小（n = 6）、生长（n = 12）或不变（n = 8）。另外9例患者（26%）在MRI-linac上病变生长，尽管T1+C部分缩小。没有患者出现T1+C病变生长而MRI-linac病变缩小的情况。
在整个放化疗疗程中，每天在MRI-linac上成像的胶质母细胞瘤患者可观察到解剖学变化。随着手术切除腔隙缩小，可缩小边缘以保留正常脑组织。未切除或病变生长的患者可能需要扩大边缘以涵盖变化。有限体积的胶质母细胞瘤强化试验在非对比剂MRI-linac上观察到病变生长时，可考虑触发钆对比剂给药以评估自适应放射治疗。
