Search Results

Object

The mean level of the conus medullaris (CM) has been estimated to lie opposite the L1/2 disc space in several previous studies using ultrasound, CT myelography, and magnetic resonance (MR) imaging, but these studies have been limited in examining only the lumbar spine and including patients being evaluated for back pain and sciatica (creating a selection bias). Moreover, significant variability was found in the termination of the CM, with a small subset of subjects having a CM as low as the mid-body of L4. The authors sought to determine the normal level of the CM and its variability.

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Children with brain or spinal cord tumors who underwent whole-spine surveillance MR imaging were identified retrospectively. The level of the CM was identified in each subject by counting down from C1. Vertebral anomalies, such as lumbarized S1, sacralized L5, or fewer rib-bearing segments, and the presence of fatty filum were noted.

Results

Findings regarding the level of termination of the CM were tightly grouped; the average was at the lower third of L1 and the mode of the distribution was at the L1/2 disc space, with very little variation. No CM ended below the mid-body of L2. The level of the CM was not significantly different among individuals with lumbarized or sacralized vertebrae or 11 rib-bearing segments.

Conclusions

The CM terminates most commonly at the L1–2 disc space and in the absence of tethering, the CM virtually never ends below the mid-body of L2. A CM that appears more caudal on neuroimages should be considered tethered.

Object

神经影像学abnor的外观和演化malities following abusive head trauma (AHT) is important for establishing the time frame over which these injuries might have occurred. From a legal perspective this frames the timing of the abuse and therefore identifies and excludes potential perpetrators. A previous pilot study involving 33 infants with AHT helped to refine the timing of these injuries but was limited by its small sample size. In the present study, the authors analyzed a larger group of 210 cases involving infants with AHT to chronicle the first appearance and evolution of radiological (CT, MRI) abnormalities.

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All children younger than 24 months admitted to the Penn State Hershey Medical Center with AHT over a 10-year period were identified from a medical record review; the time of injury was determined through an evaluation of the clinical records. All imaging studies were analyzed, and the appearance and evolution of abnormalities were chronicled on serial neuroimaging studies obtained in the days and weeks after injury.

Results

One hundred five infants with specific injury dates and available imaging studies were identified; a subset of 43 children additionally had documented times of injury. In infants with homogeneously hyperdense subdural hematomas (SDHs) on initial CT scans, the first hypodense component appeared within the SDH between 0.3 and 16 days after injury, and the last hyperdense subdural component disappeared between 2 and 40 days after injury. In infants with mixed-density SDHs on initial scans, the last hyperdense component disappeared between 1 and 181 days. Parenchymal hypodensities appeared on CT scans performed as early as 1.2 hours, and all were visible within 27 hours after the injury. Rebleeding into SDHs was documented in 17 cases (16%) and was always asymptomatic.

Magnetic resonance imaging of the brain was performed in 49 infants. Among those with SDH, 5 patterns were observed. Patterns I and II reflected homogeneous SDH; Pattern I (T1 hyperintensity and T2/FLAIR hypointensity, “early subacute”) more commonly appeared on scans performed earlier after injury compared with Pattern II (T1 hyperintensity and T2/FLAIR hyperintensity, “late subacute”), although there was considerable overlap. Patterns III and IV reflected heterogeneous SDH; Pattern III contained relatively equal mixtures having different intensities, whereas Pattern IV had fluid that was predominantly T1 hypointense and T2/FLAIR hyperintense. Again, Pattern III more commonly appeared on scans performed earlier after injury compared with Pattern IV, although there was significant overlap.

Conclusions

这些数据扩展的初步数据报告Dias and colleagues and provide a framework upon which injuries in AHT can be timed as well as the limitations on such timing estimates.