Diagnostic Performance of Ultrafast Brain MRI for Evaluation of Abusive Head Trauma

BACKGROUND AND PURPOSE:MR imaging with sedation is commonly used to detect intracranial traumatic pathology in the pediatric population. Our purpose was to compare nonsedated ultrafast MR imaging, noncontrast head CT, and standard MR imaging for the detection of intracranial trauma in patients with potential abusive head trauma.MATERIALS AND METHODS:A prospective study was performed in 24 pediatric patients who were evaluated for potential abusive head trauma. All patients received noncontrast head CT, ultrafast brain MR imaging without sedation, and standard MR imaging with general anesthesia or an immobilizer, sequentially. Two pediatric neuroradiologists independently reviewed each technique blinded to other modalities for intracranial trauma. We performed interreader agreement and consensus interpretation for standard MR imaging as the criterion standard. Diagnostic accuracy was calculated for ultrafast MR imaging, noncontrast head CT, and combined ultrafast MR imaging and noncontrast head CT.RESULTS:Interreader agreement was moderate for ultrafast MR imaging (κ = 0.42), substantial for noncontrast head CT (κ = 0.63), and nearly perfect for standard MR imaging (κ = 0.86). Forty-two percent of patients had discrepancies between ultrafast MR imaging and standard MR imaging, which included detection of subarachnoid hemorrhage and subdural hemorrhage. Sensitivity, specificity, and positive and negative predictive values were obtained for any traumatic pathology for each examination: ultrafast MR imaging (50%, 100%, 100%, 31%), noncontrast head CT (25%, 100%, 100%, 21%), and a combination of ultrafast MR imaging and noncontrast head CT (60%, 100%, 100%, 33%). Ultrafast MR imaging was more sensitive than noncontrast head CT for the detection of intraparenchymal hemorrhage (P = .03), and the combination of ultrafast MR imaging and noncontrast head CT was more sensitive than noncontrast head CT alone for intracranial trauma (P = .02).CONCLUSIONS:In abusive head trauma, ultrafast MR imaging, even combined with noncontrast head CT, demonstrated low sensitivity compared with standard MR imaging for intracranial traumatic pathology, which may limit its utility in this patient population.

The incidence of abusive head trauma (AHT) in the United States from 2000 to 2009 was 39.8 per 100,000 children younger than 1 year of age and 6.8 per 100,000 children 1 year of age.¹ The outcomes of patients with AHT are worse than those of children with accidental traumatic brain injury, including higher rates of mortality and permanent disability from neurologic impairment.^2–5 The diagnosis of AHT is frequently not recognized when affected patients initially present to a physician, and up to 28% of children with a missed AHT diagnosis may be re-injured, leading to permanent neurologic damage or even death.⁶ Because neuroimaging plays a central role in AHT, continued improvement in neuroimaging is necessary.Common neuroimaging findings of AHT include intracranial hemorrhage, ischemia, axonal injury, and skull fracture, with advantages and disadvantages for both CT and MR imaging for the detection of AHT.⁷ A noncontrast head CT (nHCT) is usually the initial imaging study in suspected AHT due to its high sensitivity for the detection of acute hemorrhage and fracture and the high level of accessibility from the emergency department, and it can be performed quickly and safely without the need for special monitoring equipment.^8,9 The disadvantages of CT include ionizing radiation, particularly in children, and the reduced sensitivity in detecting microhemorrhages, axonal injury, and acute ischemia compared with MR imaging.¹⁰MR imaging is frequently performed in AHT and adds additional information in 25% of all children with abnormal findings on the initial CT scan.¹¹ Brain MR imaging can also be useful for identifying bridging vein thrombosis, differentiating subdural fluid collections from enlarged subarachnoid spaces, characterizing the signal of subdural blood, and demonstrating membrane formation within subdural collections.^12–16 Brain MR imaging findings have correlated with poor outcomes associated with findings on diffusion-weighted imaging and susceptibility-weighted imaging in AHT; however, disadvantages of MR imaging continue to include the need for sedation in children and compatible monitoring equipment.^17–22 Although there is greater accessibility of CT compared with MR imaging, the availability of MR imaging is relatively high and imaging techniques that allow neuroimaging in patients with potential AHT without sedation would be valuable, particularly given the potential adverse effects of sedation on the developing brain.^23,24A potential solution for diagnostic-quality brain MR imaging without sedation in AHT is the use of ultrafast MR imaging (ufMRI) sequences, also termed “fast MR imaging,” “quick MR imaging,” or “rapid MR imaging.” Ultrafast MR imaging uses pulse sequences that rapidly acquire images, potentially reducing motion artifacts and the need for sedation. ufMRI has been most commonly used in pediatric neuroradiology for the evaluation of intracranial shunts in children with hydrocephalus, and most of the reported ufMRI brain protocols include only multiplanar T2-weighted HASTE sequences.^25–34 Consequently, previously reported limitations of ufMRI in detecting intracranial hemorrhage is primarily due to the lack of blood sensitive sequences.³⁵Recently, an ufMRI protocol incorporating sequences in addition to T2 sequences has been reported in pediatric patients with trauma.³⁶ This study did not compare findings with those of a standard MR imaging (stMRI) and included a wider age range of pediatric patients, so the value of ufMRI in pediatric abusive head trauma remains uncertain.³⁶ Therefore, the purpose of our study was to evaluate an ufMRI brain protocol performed without sedation for feasibility in terms of scanning time and diagnostic value as well as diagnostic accuracy compared with nHCT and stMRI of the brain for the detection of intracranial traumatic pathology in patients with suspected AHT.     

Brain Trauma Inside a Football Helmet

‘Highlights’ offers readers practical information gleaned from recent medical literature and meetings.     

非原发中枢神经系统非霍奇金淋巴瘤脑实质病变影像表现分析

目的探讨首发部位为非中枢神经系统的非霍奇金淋巴瘤(NHL)病例的脑实质病变影像学表现特点。方法经病理确诊为体部非霍奇金淋巴瘤,行CT和/或MR I扫描发现脑实质异常的病例8例。对所有病灶增强CT扫描及MR I表现分类分析。另取有结节强化表现的其他脑转移瘤73例,与NHL病例组比较。结果CT增强扫描8例,共计病灶13个,分为①强化后低密度病灶(10/13,77%),边界均较模糊;②强化后高密度病灶(3/13,23%),其中环形强化结节1个。所有病灶均未见与脑转移病灶有关的脑室扩张和占位效应,有强化表现的结节周围未见水肿带。行MR I检查4例中3例呈长T1长T2信号,增强后无特殊信号改变。1例呈中央长T1长T2信号,周边长T1中长T2信号,增强后周边环形强化,无水肿带。73例有结节强化表现的其他脑转移瘤中89%的病灶CT可见灶周不同程度水肿。结论本组病例中部分病灶表现不同于文献描述的NHL脑转移征象。而与其他脑转移瘤相比,周边无水肿带的结节状强化病灶也是本组病例的特殊表现之一。     

Ventricular Ectopy as a Predictor of Death

‘Best of the Literature’ presents summaries of sports medicine—related articles culled from more than 30 medical journals. Experts comment on what the new findings add to current medical thinking and on the implications for practice     

Intraprocedural Parenchymal Blood Volume Is a Predictor of Treatment Response for Chemoembolization in Hepatocellular Carcinoma: Results of a Prospective Study

Purpose

To evaluate cone-beam parenchymal blood volume (PBV) before and after embolization as a predictor of radiographic response to transarterial chemoembolization in unresectable hepatocellular carcinoma (HCC).

Parenchymal echotexture changes as a predictor of viability in testicular torsion

Emergency Radiology - Preoperative test that can predict the salvageability of the torsed testis may add essential information to the surgeon managing testicular torsion (TT), this can assist with...     

大鼠不同程度脑损伤模型的建立

建立了一个可定量的不同程度脑损伤模型。方法应用自由落体方法造成大鼠轻、中、重三型脑损伤模型,进行含水量,血脑屏障定量测定和超微结构观察。结果损伤越重,脑挫裂伤灶越明显,血脑屏障破坏越明显,脑水肿越重,脑水肿程度和损伤程度相关。结论建立了稳定的不同程度脑损伤模型。     

水通道蛋白-4在人脑挫裂伤早期脑水肿的作用机制探讨

目的探讨人脑挫裂伤后早期AQP4在脑水肿形成中的作用机制,为颅脑损伤后脑水肿的治疗和预后提供客观依据。方法选取经颅脑CT证实为脑挫裂伤且需手术治疗的患者。手术过程中切取脑挫裂伤区组织标本60例为观察组,10例非功能区相对正常脑组织标本为对照组。对照组不做任何处理,观察组按伤后时间分为2h、6h、8h、12h、24h、72h6个亚组,每组10只（n=10）。采用免疫组化和图像分析技术测定各组相应时间点水肿区AQP4的表达水平,同时用干湿重法检测脑水肿含水量。结果与对照组相比较,观察组在伤后2hAQP4表达开始增加（P〈0．05）,6h、8h、12h明显增加（P〈0．01）,24h-72h达到最高（P〈0．01）。AQP4表达与脑含水量的变化规律趋于一致（r=0．912,P〈0．01）。结论脑挫裂伤后AOP4表达明显增强,提示AQP4可能与颅脑损伤的发生、发展过程密切相关,在损伤后脑水肿的形成过程中起重要作用。     

Correction to: Parenchymal echotexture changes as a predictor of viability in testicular torsion

Emergency Radiology -     

64例脑外伤死亡CT回顾分析

目的:就64例脑外伤致死的CT资料,研究其外伤类型的CT征像。以提高脑外伤的CT诊断水平,探讨提示预后不良的主要类型和CT特点,以指导临床治疗。材料与方法:回顾分析64例脑外伤死亡病例的CT资料,按其具有若干种损伤分类统计,并就各种损伤表现作一总结。结果:单一损伤4例,两种损伤同时存在10例,三种损伤同时存在36例,四种以上损伤14例。结论:多种复合颅脑损伤是最常见的死亡原因,而单一损伤中弥漫性脑轴索损伤(DAI),原发全脑室出血是致死的主要原因。复合损伤中,广泛硬膜下血肿、半球脑肿胀、脑干损伤更具危险性。病灶大小和占位效应与预后有明显关系。CT检查及随访可客观反映颅脑损伤的严重程度、动态观察病情变化,为临床诊断和治疗提供可靠依据。