Tomsick T A, Wang L L, Zuccarello M, Ringer A J
From the Department of Radiology (T.A.T., L.L.W.)
From the Department of Radiology (T.A.T., L.L.W.).
AJNR Am J Neuroradiol. 2021 Apr;42(4):801-806. doi: 10.3174/ajnr.A7046. Epub 2021 Mar 11.
Cervical spine axial MRI T2-hyperintense fluid signal of the anterior median fissure and round hyperintense foci resembling either the central canal or base of the anterior median fissure are associated with a craniocaudad sagittal line, also simulating the central canal. On the basis of empiric observation, we hypothesized that hyperintense foci, the anterior median fissure, and the sagittal line are seen more frequently in patients with Chiari malformation type I, and the sagittal line may be the base of the anterior median fissure in some patients.
Saggital line incidence and the incidence/frequency of hyperintense foci and anterior median fissure in 25 patients with Chiari I malformation and 25 contemporaneous age-matched controls were recorded in this prospective exploratory study as either combined (hyperintense foci+anterior median fissure in the same patient), connected (anterior median fissure extending to and appearing to be connected with hyperintense foci), or alone as hyperintense foci or an anterior median fissure. Hyperintense foci and anterior median fissure/patient, hyperintense foci/anterior median fissure ratios, and anterior median fissure extending to and appearing to be connected with hyperintense foci were compared in all, in hyperintense foci+anterior median fissure in the same patient, and in anterior median fissure extending to and appearing to be connected with hyperintense foci in patients with Chiari I malformation and controls.
Increased sagittal line incidence (56%), hyperintense foci (8.5/patient), and anterior median fissure (4.0/patient) frequency were identified in patients with Chiari I malformation versus controls (28%, 3.9/patient, and 2.7/patient, respectively). Increased anterior median fissure/patient, decreasing hyperintense foci/anterior median fissure ratio, and increasing anterior median fissure extending to and appearing to be connected with hyperintense foci/patient were identified in Chiari subgroups. A 21%-58% increase in observed anterior median fissure extending to and appearing connected to hyperintense foci in the entire cohort and multiple sagittal line subgroups compared with predicted occurred.
In addition to the anticipated increased incidence/frequency of sagittal line and hyperintense foci in patients with Chiari I malformation, an increased incidence and frequency of anterior median fissure and anterior median fissure extending to and appearing to be connected with hyperintense foci/patient were identified. We believe an anterior median fissure may contribute to a saggital line appearance in some patients with Chiari I malformation. While thin saggital line channels are usually ascribed to the central canal, we believe some may be due to the base of the anterior median fissure, created by pulsatile CSF hydrodynamics.
颈椎轴位MRI上，前正中裂的T2高信号液体信号以及类似中央管或前正中裂底部的圆形高信号灶与一条头尾向矢状线相关，该矢状线也模拟中央管。基于经验观察，我们推测I型Chiari畸形患者中高信号灶、前正中裂和矢状线更为常见，并且在某些患者中矢状线可能是前正中裂的底部。
在这项前瞻性探索性研究中，记录了25例I型Chiari畸形患者和25例年龄匹配的同期对照者的矢状线发生率以及高信号灶和前正中裂的发生率/频率，分为合并（同一患者中高信号灶+前正中裂）、相连（前正中裂延伸并似乎与高信号灶相连）或单独作为高信号灶或前正中裂。比较了I型Chiari畸形患者和对照者中所有患者、同一患者中高信号灶+前正中裂以及前正中裂延伸并似乎与高信号灶相连的患者的高信号灶和前正中裂/患者、高信号灶/前正中裂比值，以及前正中裂延伸并似乎与高信号灶相连的情况。
与对照组相比，I型Chiari畸形患者的矢状线发生率（56%）、高信号灶（8.5/患者）和前正中裂（4.0/患者）频率增加（分别为28%、3.9/患者和2.7/患者）。在Chiari亚组中，发现前正中裂/患者增加，高信号灶/前正中裂比值降低，前正中裂延伸并似乎与高信号灶相连的患者增加。与预测值相比，整个队列和多个矢状线亚组中观察到的前正中裂延伸并似乎与高信号灶相连的情况增加了21%-58%。
除了预期的I型Chiari畸形患者中矢状线和高信号灶的发生率/频率增加外，还发现前正中裂以及前正中裂延伸并似乎与高信号灶相连的发生率和频率增加。我们认为前正中裂可能在某些I型Chiari畸形患者中导致矢状线的出现。虽然细的矢状线通道通常归因于中央管，但我们认为有些可能是由于搏动性脑脊液流体动力学形成的前正中裂底部。
