Ultrasound to Evaluate Neonatal Spinal Dysraphism: A First‐Line Alternative to CT and MRI

The embryologic development of the spinal cord is a remarkably complex process. Spinal abnormalities can occur in isolation or be part of a clinical syndrome commonly summarized as spinal dysraphism. Proper evaluation of spinal malformations with imaging is required for early diagnosis prior to counseling and selection of postnatal treatment options. The preferred imaging modality of the spine in newborns up to 3 months of age are ultrasound (US) and magnetic resonance imaging (MRI). The diagnostic workup should preferably start with the safe, minimal invasive (no need for sedation), cost‐effective, and bedside US as a screening procedure. On the other hand, need for sedation, thermal instability of infants, and high cost make the use of spinal MRI impracticable for screening purposes. US is also a well‐established imaging modality to investigate the spinal cord and canal during pregnancy. It is critical to follow a strict protocol in an attempt to precisely identify all imaging findings, one should be familiar with the normal ultrasonographic appearance of bony and soft tissue structures in the various planes and one should be able to correlate the abnormal findings with spinal cord embryology as it aids in identifying the etiology. US should be considered as a first‐line imaging for neonates suspected of spinal anomalies. In this article, we discuss up‐to‐date US technique of the spine, the most frequently encountered neonatal spinal malformations seen with US and correlate these findings with the relevant embryologic processes.     

Contrast-enhanced Ultrasound in Dermatomyositis- and Polymyositis

Objective To evaluate prospectively contrast-enhanced ultrasound (CEUS) in patients suspected of having dermatomyositis or polymyositis. Methods In 35 patients (23 women, 12 men; mean age, 51 years ± 16 years) who were suspected of having dermatomyositis or polymyositis, perfusion in clinically affected skeletal muscles was quantified with contrast-enhanced intermittent power Doppler ultrasound. By applying a modified model that analyzed the replenishment kinetics of microbubbles, the perfusion-related parameters blood flow, local blood volume and blood flow velocity were measured. Findings were compared with muscle biopsy appearances and with the results of MRI that was performed with a 1.5-Tesla unit. Receiver operating characteristic analysis was performed and optimum thresholds for diagnosis of myositis were determined. Results Eleven patients had histologically confirmed dermatomyositis or polymyositis and showed significantly higher blood flow velocity (P = .01 for dermato- and P < .001 for polymyositis), blood flow (P < .001 for dermato- and polymyositis), and blood volume (P = .007 for dermato- and P < .001 for polymyositis) on contrast-enhanced ultrasound than those who did not have myositis. An increase in signal intensity on T2-weighted MR images was found in all patients with myositis. MRI had a sensitivity, specificity, positive (PPV), and negative predicting values (NPV) of 100%, 88%, 77%, and 100% for diagnosis of myositis, respectively. CEUS blood flow was the best ultrasound measure for diagnosis of dermato- or polymyositis with sensitivity, specificity, PPV, and NPV of 73%, 91%, 80%, and 88%, respectively. Conclusions Increased skeletal muscle perfusion measured by CEUS could serve as an additional measurer for the diagnosis of an inflammatory myopathy. Received in revised form: 6 June 2006 An erratum to this article is available at .     

Combined contrast-enhanced ultrasound and rt-PA treatment is safe and improves impaired microcirculation after reperfusion of middle cerebral artery occlusion

In monitoring of recanalization and in sonothrombolysis, contrast-enhanced ultrasound (CEUS) is applied in extended time protocols. As extended use may increase the probability of unwanted effects, careful safety evaluation is required. We investigated the safety profile and beneficial effects of CEUS in a reperfusion model. Wistar rats were subjected to filament occlusion of the right middle cerebral artery (MCA). Reperfusion was established after 90 minutes, followed by recombinant tissue-type plasminogen activator (rt-PA) treatment and randomization to additional CEUS (contrast agent: SonoVue; 60 minutes). Blinded outcome evaluation consisted of magnetic resonance imaging (MRI), neurologic assessment, and histology and, in separate experiments, quantitative 3D nano-computed tomography (CT) angiography (900 nm³ voxel size). Nano-CT revealed severely compromised microcirculation in untreated animals after MCA reperfusion. The rt-PA partially improved hemispheric perfusion. Impairment was completely reversed in animals receiving rt-PA and CEUS. This combination was more effective than treatment with either CEUS without rt-PA or rt-PA and ultrasound or ultrasound alone. In MRI experiments, CEUS and rt-PA treatment resulted in a significantly reduced ischemic lesion volume and edema formation. No unwanted effects were detected on MRI, histology, and intracranial temperature assessment. This study shows that CEUS and rt-PA is safe in the situation of reperfusion and displays beneficial effects on the level of the microvasculature.     

TCD, MRA and MRI in acute cerebral ischemia

Objectives - The aim of this study was to determine accuracy of transcranial Doppler ultrasound (TCD) and compare efficacy of three non-invasive tests [TCD, magnetic resonance angiography (MRA), and magnetic resonance imaging (MRI)] in patients with acute cerebral ischemia. Material and methods - This prospective study involved 30 patients. MRI, MRA, and TCD were performed within 24 h after onset of ictus. The 2nd MRI was repeated at 48–72 h and was used as the standard for the evaluation of sensitivity and specificity of MRA, TCD, and initial MRI. Results - TCD showed a sensitivity of 96% and a specificity of 33% for recognizing abnormal cerebral blood flow velocities. MRA showed a sensitivity of 46% and a specificity of 75% for assessing intracranial vascular anatomy, while initial MRI revealed a sensitivity of 84% and a specificity of 100% for evaluation of ischemic parenchymal changes. Conclusion - Our results revealed that TCD is an accurate indicator of blood flow status and correlated well with MRI, MRA abnormalities in acute stroke.     

基于人工智能斑块分割超声图像的影像组学在颈动脉斑块稳定性评估中的应用

目的 探讨基于人工智能斑块分割超声图像的影像组学评估颈动脉斑块的稳定性,以及其对颈动脉易损斑块与稳定性斑块的诊断效能.方法 171例缺血性脑卒中患者通过颈动脉彩超检查分为易损斑块组(83例)与稳定斑块组(88例).在人工智能斑块分割超声图像上提取369个影像组学特征,采用最小绝对收缩和选择算子方法 对影像组学特征进行降...     

Emerging technologies in neuromuscular ultrasound

Neuromuscular ultrasound is an accepted and valuable element in the evaluation of peripheral nerve and muscle disease. However, ultrasound has several limitations to consider, including operator dependency and lack of a viable contrast agent. Fortunately, new technological advances show promise in resolving these issues. Ultra-high resolution ultrasound enables imaging of the nerve at the fascicular level. Shear wave elastography imaging can provide measures of tissue stiffness that can act as a surrogate measure of nerve and muscle health. Photoacoustic imaging may overcome neuromuscular ultrasound's current lack of contrast agents to detect inflammation and other functional changes within nerve and muscle, while artificial intelligence stands to address operator dependency and improve diagnostic imaging. The basic principles of each of these technologies are discussed along with current research and potential future applications in neuromuscular imaging.     

The current role of diagnostic imaging in the preoperative workup for refractory neonatal brachial plexus palsy

Introduction

Despite recent improvements in perinatal care, the incidence of neonatal brachial plexus palsy (NBPP) remains relatively common. CT myelography is currently considered to be the optimal imaging modality for evaluating nerve root integrity. Recent improvements in MRI techniques have made it an attractive alternative to evaluate nerve root avulsions (preganglionic injuries).

Aim

We demonstrate the utility of MRI for the evaluation of normal and avulsed spinal nerve roots. We also show the utility of ultrasound in providing useful preoperative evaluation of the postganglionic brachial plexus in patients with NBPP.

     

Advanced Pediatric Neurosonography Techniques: Contrast‐Enhanced Ultrasonography,Elastography, and Beyond

Recent technical advances in neurosonography continue broadening the diagnostic utility, sensitivity, and specificity of ultrasound for detecting intracranial abnormalities bed side. The clinical and functional applications of neurosonography have significantly expanded since the 1980s when transcranial Doppler sonography first allowed anatomic and hemodynamic delineation of the intracranial vessels through the thin temporal skull. In the past few years, contrast‐enhanced ultrasonography, elastography, 3D/4D reconstruction tools, and high‐resolution microvessel imaging techniques have further enhanced the diagnostic significance of neurosonography. Given these advances, a thorough familiarity with these new techniques and devices is crucial for a successful clinical application allowing improved patient care. It is essential that future neurosonography studies compare these advanced techniques against the current “gold standard” computed tomography and magnetic resonance imaging to assure the accuracy of their diagnostic potential. This review will provide a comprehensive update on currently available advanced neurosonography techniques.     

Prenatal diagnosis of suprasellar arachnoid cyst and postnatal endoscopic treatment

Arachnoid cysts are benign developmental anomalies that occur in the cerebrospinal axis in relation to the arachnoid membrane. An antenatal ultrasound scan first raises the suspicion of arachnoid cysts, but misdiagnoses have been reported. Confirmatory antenatal magnetic resonance imaging (MRI) is very useful to delineate anatomical detail and help in correct diagnosis. This helps proper counselling and treatment planning. Controversy also surrounds the surgical management, in terms of both the indications and the procedures employed. We report the successful endoscopic treatment, in a neonate, of an arachnoid cyst diagnosed by antenatal ultrasound and MRI. In this case accurate diagnosis and detailed assessment led to objective counselling and helped to optimise neonatal management.     

Neurological, electrophysiological and MRI abnormalities in infants with extensive cystic leukomalacia

Twenty infants, diagnosed by cranial ultrasound as having extensive cystic leukomalacia, had visual evoked responses (VER) and electroencephalograms (EEG) in the neonatal period and MRI scans later in infancy. The early ultrasound findings and results from the electrophysiological tests were correlated with later MRI findings and functional abilities. In infants with periventricular leukomalacia (PVL), the cysts were usually no longer visible by ultrasonography, beyond 40 weeks postmenstrual age (PMA), but later MRI scans showed a consistent pattern of delayed myelination around the irregularly dilated occipital horns of the lateral ventricles. VER's were present in the neonatal period and vision was maintained, although all infants developed a marked squint. EEG's were either normal or abnormal initially, but improvement was noted within several weeks. In those with subcortical or mixed lesions, cysts were noted to persist beyond 40 weeks PMA. Later MRI scans showed very poor myelination, with poor progress on subsequent scans and cortical atrophy. VER's were absent and all infants later became cortically blind. EEG's were severely abnormal and recovery was very poor. The infants with PVL developed spastic diplegia with moderate developmental delay, while those with mixed or subcortical lesions developed quadriplegia with severe mental retardation. An integrated approach, consisting of ultrasound imaging and electrophysiological recordings in the neonatal period and MRI imaging later in infancy, may provide a more reliable prediction of the pattern of later deficits.     

Comparative neuroimaging with pathologic correlates in Alexander's disease

We describe a case of pathologically confirmed Alexander's disease in which serial cranial ultrasound studies demonstrated unique findings of enlarging subependymal cysts with evolving periventricular hyperechogenicity. Computed tomographic scan of the head showed low attenuation of the periventricular white matter and centrum semiovale. Magnetic resonance imaging (MRI) demonstrated diffuse, confluent high signal predominantly in frontal white matter. These imaging modalities, particularly cranial ultrasound and MRI, may be useful tools in the diagnostic evaluation of children with degenerative neurologic disease, megalencephaly, and suspected Alexander's disease.     

Ultrasound elastography for the evaluation of peripheral nerves: A systematic review

Peripheral nerve disorders are commonly encountered in clinical practice. Electrodiagnostic studies remain the cornerstone of the evaluation of nerve disorders. More recently, ultrasound has played an increasing complementary role in the neuromuscular clinic. Ultrasound elastography is a technique that measures the elastic properties of tissues. Given the histological changes that occur in diseased peripheral nerves, nerve ultrasound elastography has been explored as a noninvasive way to evaluate changes in nerve tissue composition. Studies to date suggest that nerve stiffness tends to increase in the setting of peripheral neuropathy, regardless of etiology, consistent with loss of more compliant myelin, and replacement with connective tissue. The aim of this systematic review is to summarize the current literature on the use of ultrasound elastography in the evaluation of peripheral neuropathy. Limitations of ultrasound elastography and gaps in current literature are discussed, and prospects for future clinical and research applications are raised.     

The prediction of postoperative hydrocephalus in patients with spina bifida

Object The object was to derive a prediction rule for the development of postoperative hydrocephalus in patients with spina bifida by the measurement of cranial ventricular diameters using ultrasound.Methods Eighty-nine patients with spina bifida were studied prospectively. Each child had preoperative cranial ultrasound with measurement of the bifrontal diameter, bicaudate diameter and maximum transverse diameter of the body of the lateral ventricle by a single blinded observer. Repair of meningomyelocele was then undertaken and the patients followed up for development or progression of hydrocephalus. Logistic regression analysis determined the lowest values of the three cranial ventricular diameters associated with the maximum sensitivity and specificity for predicting postoperative hydrocephalus. These values were—bifrontal diameter >26 mm, bicaudate diameter >20 mm and body of lateral ventricle diameter >26 mm.Conclusions It is possible to predict the development of postoperative hydrocephalus in patients with spina bifida by measuring cranial ventricular dimensions using preoperative ultrasound.     

Predictive value of neonatal MRI with respect to late MRI findings and clinical outcome. A study in infants with periventricular densities on neonatal ultrasound

PURPOSE: The aim of this study was to correlate hypoxic-ischemic white matter damage on neonatal MRI with MRI appearance and neurological outcome at the age of 1 1/2 years. PATIENTS AND METHODS: A sequential cohort of infants with periventricular densities on neonatal ultrasound was studied with neonatal MRI. Images of 46 infants with a mean gestational age of 31 weeks were obtained at a mean age of 20 days after birth and at 1 1/2 years. To establish agreement between the neonatal and follow-up MRI (general, motor, and visual scores), the weighted Cohen's kappa test was used. To establish the predictive power of neonatal MRI with respect to the neurologic indices at the age of 1 1/2 years, the sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS: There was a moderately good to good agreement between the general, motor, and visual neonatal and follow-up MRI scores: weighted kappa = 0.59 (95% CI: 0.44 - 0.74), 0.82 (95% CI: 0.72 - 0.93), and 0.70 (95% CI: 0.56 - 0.84), respectively. Neonatal MRI scores provided a good prediction of the three neurological outcome measures (developmental delay, cerebral palsy, and cerebral visual impairment): sensitivity, specificity, and predictive values were high, with little difference between the three MRI scores. The 32 patients with (nearly) normal neonatal MRI scores were neurologically (nearly) normal at 1 1/2 years on all three outcome measures, whereas 8 patients with seriously abnormal neonatal MRI scores were neurologically abnormal at 1 1/2 years on all three outcome measures. CONCLUSION: Neonatal MRI is able to predict the precise localization and size of perinatal leukomalacia on follow-up MRI and provides a good prediction of neurological outcome at 1 1/2 years.     

经硬膜下入路显微手术切除大型海绵窦血管瘤

目的探讨大型海绵窦血管瘤(cavernous sinus hemangiomas,CSH)的影像学表现及治疗方式。方法对经手术术后病理证实的4例大型CSH的影像学及临床资料进行回顾性分析,并复习相关文献。4例患者均做头颅MRI、头颅CTA扫描,后经硬膜下入路行显微外科手术治疗。结果病变在头颅MRI上呈等T1、边缘锐利的短T2表现、FLAIR高信号,增强后快速均匀强化或延迟欠均匀强化(最终达到均匀强化),肿瘤不同程度向中颅窝、鞍区、鞍上生长;头颅CTA显示肿瘤无明显供血动脉,但周边细小血管丰富;4例患者均只做到部分切除。术中平均失血3425 ml,术后3例出现颅神经功能障碍。结论根据头颅MRI特征性表现基本能诊断CSH,相比显微手术潜在的风险,射波刀放疗效果显著,可能会逐步成为本病的首选治疗方式。     

A systematic review of tests to predict cerebral palsy in young children

Aim

This systematic review evaluates the accuracy of predictive assessments and investigations used to assist in the diagnosis of cerebral palsy (CP) in preschool‐age children (<5y).

Method

Six databases were searched for studies that included a diagnosis of CP validated after 2 years of age. The validity of the studies meeting the criteria was evaluated using the Standards for Reporting Diagnostic Accuracy criteria. Where possible, results were pooled and a meta‐analysis was undertaken.

Results

Nineteen out of 351 studies met the full inclusion criteria, including studies of general movements assessment (GMA), cranial ultrasound, brain magnetic resonance imaging (MRI), and neurological examination. All studies assessed high‐risk populations including preterm (gestational range 23–41wks) and low‐birthweight infants (range 500–4350g). Summary estimates of sensitivity and specificity of GMA were 98% (95% confidence interval [CI] 74–100%) and 91% (95% CI 83–93%) respectively; of cranial ultrasound 74% (95% CI 63–83%) and 92% (95% CI 81–96%) respectively; and of neurological examination 88% (95% CI 55–97%) and 87% (95% CI 57–97%) respectively. MRI performed at term corrected age (in preterm infants) appeared to be a strong predictor of CP, with sensitivity ranging in individual studies from 86 to 100% and specificity ranging from 89 to 97% There was inadequate evidence for the use of other predictive tools.

Summary

This review found that the assessment with the best evidence and strength for predictive accuracy is the GMA. MRI has a good predictive value when performed at term‐corrected age. Cranial ultrasound is as specific as MRI and has the advantage of being readily available at the bedside. Studies to date have focused on high‐risk infants. The accuracy of these tests in low‐risk infants remains unclear and requires further research.     

Carotid Body Tumors: Advantages of Contrast Ultrasound Investigation

Carotid body tumors are rare neoplasms that have to be considered in the evaluation of all lateral neck mass. Early surgical removal has been recommended to avoid possible cranial nerve injury, the most common perioperative complication. Computed tomography (CT) and magnetic resonance imaging (MRA) angiographies are the preferred pre-operative diagnostic imaging investigations, as well as the 111 In-pentetreotide scintigraphic scan, whereas the standard ultrasound investigations have poor sensitivity in characterizing of the blood flows of the parenchimal structure of the carotid body tumors. We describe a case of a patient with a carotid body tumor assessed with contrast ultrasonography that clearly improved the quality of the standard color Duplex. This technique may represent a non-invasive method, easy to use and to repeat, and able to achieve high diagnostic accuracy.     

多模态超声评价颈动脉斑块易损性的多因素分析

目的 将二维超声、微血管成像技术、超声造影颈动脉斑块相关的声像图特征及临床卒中的危险因 素纳入Logistic回归，明确对缺血性卒中最有影响的斑块特征及危险因素，明确超声联合诊断效能。      

磁共振成像预测颅内肿瘤质地的研究进展

术前对颅内肿瘤质地的准确评估对于手术入路的选择以及预后的评估极为重要。目前,对颅内肿瘤质地的预测方法主要是通过磁共振成像。本文分别对磁共振常规序列、弥散序列、弹性序列及其他序列预测肿瘤质地研究相关的文献进行综述和分析。我们认为常规序列和弥散序列预测肿瘤质地的有效性尚存在争议;磁共振波谱、灌注加权成像及稳态进动平衡序列目前研究数据较少,不能得出有效的结论;弹性序列是目前预测肿瘤质地最有效的评价指标。     

闭塞性脑血管病经颅多谱勒超声和脑血管造影的比较

观察经颅多谱勒超声对颈部和颅内血管狭窄诊断的可靠性。方法收集患者１１０例，分为非脑血管病，非闭塞性脑血管病、闭塞性脑血管病三组。分别用２Ｈｚ和４Ｈｚ多谱勒探头检查颅脑和颈部大动脉的血流速度，然后做数字减影血管造影。结果在闭塞性脑血管病驵菘检查血管７７１条，多谱勒超声发现狭窄血管１２４条，６４７条正常，其中１１３第与ＤＳＡ所见一致，ＤＳＡ发现另外１８条狭窄的智力 。