Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, WCB90, 330 Brookline Ave, Boston, MB, 02215, USA.
Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
Neuroradiology. 2022 Dec;64(12):2307-2314. doi: 10.1007/s00234-022-02993-y. Epub 2022 Jun 14.
Some patients with idiopathic intracranial hypertension (IIH) have cerebellar tonsillar herniation ≥ 5 mm mimicking Chiari malformation I (CMI), which can result in misdiagnosis and unjustified treatment. Our purpose was to identify IIH patients with tonsillar herniation ≥ 5 mm (IIH) and compare with CMI patients to assess imaging findings that could distinguish the two conditions.
Ninety-eight patients with IIH, 81 patients with CMI, and 99 controls were retrospectively assessed. Two neuroradiologists blindly reviewed MR images. IIH patients were compared with CMI patients and controls regarding the extent of tonsillar herniation (ETH), bilateral transverse sinus stenosis (BTSS), hypophysis-sella ratio (HSR), and bilateral tortuosity of optic nerve (BTON).
13/98 (13.2%) IIH patients had tonsillar herniation ≥ 5 mm (IIH) and were significantly younger and had higher BMI compared with CMI patients and controls. ETH was significantly less in the IIH than CMI (6.5 ± 2.4 mm vs. 10.9 ± 4.4 mm; p < 0.001). BTSS and HSR < 0.5 were more common in IIH than CMI (p < 0.001 and p = 0.003, respectively). No differences were seen between CMI and controls. BTON was significantly more common in IIH compared to control (p = 0.01) but not to the CMI (p = 0.36). Sensitivity and specificity to differentiate IIH from CMI were 69.2% and 96.1% for BTSS and 69.2% and 75.3% for HSR < 0.5.
The presence of BTSS and/or HSR < 0.5 in patients with ETH ≥ 5 mm should suggest further evaluation to exclude IIH before considering CMI surgery.
一些特发性颅内高压（IIH）患者存在小脑扁桃体下疝≥5mm，类似于 Chiari 畸形 I（CMI），这可能导致误诊和不合理的治疗。我们的目的是识别存在小脑扁桃体下疝≥5mm（IIH）的 IIH 患者，并与 CMI 患者进行比较，以评估可区分两种情况的影像学发现。
回顾性评估了 98 例 IIH 患者、81 例 CMI 患者和 99 例对照者。两位神经放射科医生盲法分析了磁共振成像（MRI）图像。IIH 患者与 CMI 患者和对照者比较，评估了小脑扁桃体下疝程度（ETH）、双侧横窦狭窄（BTSS）、垂体-蝶鞍比率（HSR）和双侧视神经迂曲（BTON）。
13/98（13.2%）例 IIH 患者存在小脑扁桃体下疝≥5mm（IIH），与 CMI 患者和对照者相比，这些患者显著更年轻，BMI 更高。IIH 患者的 ETH 明显小于 CMI（6.5±2.4mm 比 10.9±4.4mm；p<0.001）。BTSS 和 HSR<0.5 在 IIH 中比 CMI 更常见（p<0.001 和 p=0.003）。CMI 与对照者之间无差异。与对照者相比，IIH 中 BTON 更常见（p=0.01），但与 CMI 相比无差异（p=0.36）。BTSS 和 HSR<0.5 用于区分 IIH 和 CMI 的敏感性和特异性分别为 69.2%和 96.1%和 69.2%和 75.3%。
存在 ETH≥5mm 且伴有 BTSS 和/或 HSR<0.5 的患者，应进一步评估以排除 IIH，然后再考虑 CMI 手术。
