PMC8769462_01
Preoperative radiological images: Head CT on day 1 revealed right ASDH (A). On day 2, CT revealed no hematoma expansion (B). On day 3, T2WI and FLAIR image did not show brain edema nor SCLI (blue arrowheads in C), and ASL image described increased CBF against the brain compression (circle in C). On day 7, T2WI and FLAIR image showed no brain edema, but mild SCLI was observed (yellow arrowheads in D). ASL image showed no left-right difference of the CBF (D). On day 14, FLAIR image revealed more apparent SCLI just under the brain compression (red arrowheads in E), then we performed surgical hematoma removal. ASL: arterial spin labeling, CBF: cerebral blood flow, CT: computed tomography, FLAIR: fluid-attenuated inversion recovery, SCLI: subcortical low intensity, T2WI: T2-weighted image.
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F1
Head computed tomography (CT) revealed right ASDH with 11 mm thickness (Fig. 1A). On the next day, head CT revealed no hematoma expansion (Fig. 1B). On day 3, T2-weighted image (T2WI) and FLAIR image did not show brain edema nor SCLI (blue arrowheads in Fig. 1C), and ASL image described increased CBF against the brain compression by the hematoma (circle in Fig. 1C). T2WI and FLAIR image on day 7 also showed no brain edema, but mild SCLI was observed (yellow arrowheads in Fig. 1D). ASL image showed no left-right difference of the CBF (Fig. 1D). FLAIR image revealed more apparent SCLI just under the ASDH compressing the brain (red arrowheads in Fig. 1E). T2WI (Fig. 1E), we determined to perform a burr hole and drainage surgery under local anesthesia. The patient's head was rotated contralateral to the hematoma side and placed on a horseshoe headrest. As a side note, the diffusion-weighted image and apparent diffusion coefficient map consistently revealed a slightly low-intensity area in the same regions where SCLI was observed on FLAIR images (Supplementary Figs. 1 and 2; Supplementary figures are available online).
Preoperative CT image (A). A 3-cm linear skin incision was made parallel to the coronal suture, and a burr hole was made on the point under which the hematoma thickness was largest (B). Rigid hematoma (red arrow in C) was endoscopically evacuated by suction cannula (gray arrow in C). Some of the hematoma was too stiff to be evacuated (D), so we used micro-scissors to remove the hematoma as piecemeal (E). We intentionally left some part of the hard hematoma in the parietal and posterior regions (green arrow in F). As endoscopic findings, the outer membrane seemed red, suggesting inflammation (blue arrows in C, F). The postoperative CT showed sufficient decompression (G) with small craniotomy (H). CT: computed tomography.
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F2
We took emergent CT (Fig. 2A) and determined to perform a surgical intervention. A 3-cm linear skin incision was made parallel to the coronal suture, and a burr hole was made on the point under which the hematoma thickness was largest (Fig. 2B). Under the endoscopic observation, rigid hematoma (red arrow in Fig. 2C) was evacuated by suction cannula (gray arrow in Fig. 2C). Some of the hematoma was too stiff to be evacuated (Fig. 2D), so we sometimes used micro-scissors to remove the hematoma as piecemeal (Fig. 2E). The hematoma just above the primary motor cortex seemed to be adequately removed, so we intentionally left some part of the hard hematoma in the parietal and posterior regions, which was not associated with her paresis (green arrow in Fig. 2F). As endoscopic findings, the outer membrane seemed red, suggesting inflammation (blue arrows in Figs. 2C, 2F). The postoperative CT showed sufficient decompression (Fig. 2G) with small craniotomy (colored yellow in Fig. 2H). As a side note, the diffusion-weighted image and apparent diffusion coefficient map consistently revealed a slightly low-intensity area in the same regions where SCLI was observed on FLAIR images (Supplementary Figs. 1 and 2; Supplementary figures are available online).
Postoperative radiological images: On day 15, T2WI and FLAIR images showed no brain edema nor hemorrhage, but SCLI was still observed (red arrowheads in A). ASL image showed CBF increase in the cortex, especially under the removed hematoma (circle in A). On day 23, the SCLI remained in the FLAIR image (red arrowheads in B), but ASL image showed normalized CBF (B). SCLI was consistently observed in the FLAIR images on days 30 and 37 (red arrowheads in C and D). However, CBF easily changed depending on the blood pressure increase (circle in C) and decrease (D). FLAIR: fluid-attenuated inversion recovery, SCLI: subcortical low intensity, T2WI: T2-weighted image.
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F3
T2WI and FLAIR images showed no brain edema nor hemorrhage, but SCLI was still observed (red arrowheads in Fig. 3A). ASL image showed CBF increase in the cortex, especially under the removed hematoma (circle in Fig. 3A). The SCLI was still observed on the FLAIR image on day 23 (red arrowheads in Fig. 3B), but ASL image showed normalized CBF (Fig. 3B). However, the SCLI was still observed on the FLAIR image on day 30 (red arrowheads in Fig. 3C), and ASL image showed CBF increase (circle in Fig. 3C). ASL image showed normalized CBF (Fig. 3D). As we described above, consistently after the surgery, the SCLI on the FLAIR image had been observed, and CBF was changed easily depending on the blood pressure in the chronic phase.