Multifocal Signal Loss at Bridging Veins on Susceptibility-Weighted Imaging in Abusive Head Trauma

Is bridging vein rupture/thrombosis associated with subdural hematoma at birth?

BACKGROUND

The combination of bridging vein rupture/thrombosis and subdural hematoma in infants has recently gained attention as highly suggestive of abusive head trauma. While subdural hematomas are frequently observed at birth, there are no previous studies of bridging vein rupture/thrombosis prevalence in that context.

OBJECTIVE

To evaluate the prevalence of bridging vein rupture/thrombosis in newborns with and without subdural hematoma.

MATERIALS AND METHODS

This bicentric retrospective study (2012-2019) looked at all brain MRIs performed in neonates. We noted delivery method, demographic data and intracranial injuries and analyzed any clots at the vertex as potential markers of bridging vein rupture/thrombosis.

RESULTS

We analyzed 412 MRIs in 412 neonates. Age was (mean ± standard deviation [SD]) 5.4±2.2 days and 312 (76%) infants were full term (38.3±2.9 weeks from last menstrual period). The delivery method was vaginal birth for 42% (n=174), cesarean section for 43% (n=179), and unknown for 14% (n=59). Subdural hematoma was present in 281 MRIs (68.0%, [95% confidence interval = 63.3-72.5]). Six MRIs showed at least one clot at the vertex, assumed to be possible bridging vein rupture/thrombosis (1.5%, [0.5-3.1%]). Only one MRI showed more than two clots at the vertex, in a context of maternal infection. There was no significant difference in terms of gestational age at birth, delivery method or the presence of subdural hematoma or parenchymal injuries between those 6 infants and the 406 others.

CONCLUSION

Bridging vein rupture/thrombosis at birth is very rare and unlikely to be related to subdural hematoma.

Chronic subdural hemorrhage predisposes to development of cerebral venous thrombosis and associated retinal hemorrhages and subdural rebleeds in infants

For infants presenting with subdural hemorrhage, retinal hemorrhage, and neurological decline the "consensus" opinion is that this constellation represents child abuse and that cerebral venous sinus thrombosis and cortical vein thrombosis is a false mimic. This article contends that this conclusion is false for a subset of infants with no evidence of spinal, external head, or body injury and is the result of a poor radiologic evidence base and misinterpreted data. Underdiagnosis of thrombosis is the result of rapid clot dissolution and radiologic under recognition. A pre-existing/chronic subdural hemorrhage predisposes to development of venous sinus thrombosis/cortical vein thrombosis, triggered by minor trauma or an acute life-threatening event such as dysphagic choking, variably leading to retinal and subdural hemorrhages and neurologic decline. These conclusions are based on analysis of the neuroradiologic imaging findings in 11 infants, all featuring undiagnosed cortical vein or venous sinus thrombosis. Subtle neuroradiologic signs of and the mechanisms of thrombosis are discussed. Subarachnoid hemorrhage from leaking thrombosed cortical veins may be confused with acute subdural hemorrhage and probably contributes to the development of retinal hemorrhage ala Terson's syndrome. Chronic subdural hemorrhage rebleeding from minor trauma likely occurs more readily than bleeding from traumatic bridging vein rupture. Radiologists must meet the challenge of stringent evaluation of neuro imaging studies; any infant with a pre-existing subdural hemorrhage presenting with neurologic decline must be assumed to have venous sinus or cortical vein thrombosis until proven otherwise.

Thrombosis is not a marker of bridging vein rupture in infants with alleged abusive head trauma

Aim

Thrombosis of bridging veins has been suggested to be a marker of bridging vein rupture, and thus AHT, in infants with subdural haematoma.

Methods

This is a non‐systematic review based on Pubmed search, secondary reference tracking and authors’ own article collections.

Results

Radiological studies asserting that imaging signs of cortical vein thrombosis were indicative of traumatic bridging vein rupture were unreliable as they lacked pathological verification of either thrombosis or rupture, and paid little regard to medical conditions other than trauma. Autopsy attempts at confirmation of ruptured bridging veins as the origin of SDH were fraught with difficulty. Moreover, microscopic anatomy demonstrated alternative non‐traumatic sources of a clot in or around bridging veins. Objective pathological observations did not support the hypothesis that a radiological finding of bridging vein thrombosis was the result of traumatic rupture by AHT. No biomechanical models have produced reliable and reproducible data to demonstrate that shaking alone can be a cause of bridging vein rupture.

Conclusion

There is no conclusive evidence supporting the hypothesis that diagnostic imaging showing thrombosed bridging veins in infants correlates with bridging vein rupture. Hence, there is no literature support for the use of thrombosis as a marker for AHT.

[Nonaccidental traumatic brain injury in infants and children]

Violent traumatic brain injury (TBI) can cause brain dysfunction and injury. Accidental and nonaccidental trauma are still the leading cause of childhood death worldwide. It is assumed that about 20% of TBI in children under 2 years of age are nonaccidentally caused. In all cases, nonaccidental TBI is caused by the violent impact on the brain and spinal cord by the massive shaking of the child held by the upper arms or body. This can lead to a rupture of blood vessels, especially bridge veins, as well as axonal shear injuries to the nerve connections and brain swelling. Involvement of the brain stem can lead to initial short-term respiratory arrest. The resulting clinical symptoms include poor drinking, drowsiness, apathy, cerebral seizures, breathing disorders, temperature disorders, and vomiting as a result of increased intracranial pressure. Long-term disorders can include neurological and neuropsychological disorders, hearing disorders, visual disorders up to blindness, and poor school performance. In addition, there are metaphyseal fractures and rib fractures of various forms, also of different ages. Since shaking trauma has a poor prognosis, preventive measures are useful: education!

Venous injury in pediatric abusive head trauma: a pictorial review

Abusive head trauma (AHT) is the leading cause of fatal head injuries in children younger than 2 years. An intracranial pathology can exist even in the setting of a normal physical exam. A delay in the diagnosis of AHT can have serious life-threatening consequences for the child and increases the potential the child will be abused again. In this article, we review the traumatic subdural hematoma as well as various morpho-structural patterns of shearing injuries and thrombosis of intracranial bridging veins. This work serves as a summary of patterns of imaging features of intracranial venous injury in AHT, as described in the literature, to facilitate familiarity and early detection of abusive head trauma in the pediatric population. Essentially, in AHT there is a traumatic injury to the bridging vein with either partial or complete tear. This can secondarily result in thrombosis at the terminal end of the bridging vein with blood clots adjacent to the bridging vein.

Venous injury in pediatric abusive head trauma: a pictorial review

Abusive head trauma (AHT) is the leading cause of fatal head injuries in children younger than 2 years. An intracranial pathology can exist even in the setting of a normal physical exam. A delay in the diagnosis of AHT can have serious life-threatening consequences for the child and increases the potential the child will be abused again. In this article, we review the traumatic subdural hematoma as well as various morpho-structural patterns of shearing injuries and thrombosis of intracranial bridging veins. This work serves as a summary of patterns of imaging features of intracranial venous injury in AHT, as described in the literature, to facilitate familiarity and early detection of abusive head trauma in the pediatric population. Essentially, in AHT there is a traumatic injury to the bridging vein with either partial or complete tear. This can secondarily result in thrombosis at the terminal end of the bridging vein with blood clots adjacent to the bridging vein.

Shaken Baby Syndrome: Magnetic Resonance Imaging Features in Abusive Head Trauma

In the context of child abuse spectrum, abusive head trauma (AHT) represents the leading cause of fatal head injuries in children less than 2 years of age. Immature brain is characterized by high water content, partially myelinated neurons, and prominent subarachnoid space, thus being susceptible of devastating damage as consequence of acceleration–deceleration and rotational forces developed by violent shaking mechanism. Diagnosis of AHT is not straightforward and represents a medical, forensic, and social challenge, based on a multidisciplinary approach. Beside a detailed anamnesis, neuroimaging is essential to identify signs suggestive of AHT, often in absence of external detectable lesions. Magnetic resonance imaging (MRI) represents the radiation-free modality of choice to investigate the most typical findings in AHT, such as subdural hematoma, retinal hemorrhage, and hypoxic-ischemic damage and it also allows to detect more subtle signs as parenchymal lacerations, cranio-cervical junction, and spinal injuries. This paper is intended to review the main MRI findings of AHT in the central nervous system of infants, with a specific focus on both hemorrhagic and non-hemorrhagic injuries caused by the pathological mechanisms of shaking. Furthermore, this review provides a brief overview about the most appropriate and feasible MRI protocol to help neuroradiologists identifying AHT in clinical practice.

Novel in vivo depiction of optic nerves hemorrhages in child abuse: a 3D-SWI pilot study

Purpose

Until now, the diagnosis of optic nerves hemorrhages in abusive head trauma (AHT) has been obtained only in the postmortem setting. The aim of the IRB-approved study was to assess the presence of optic nerves hemorrhages in AHT patients using 3D-SWI.

Methods

Thirteen children with a final confirmed multidisciplinary diagnosis of AHT underwent coronal and axial 3D-SWI imaging of the orbits. The presence of optic nerve sheath (ONS) hemorrhages was defined by thickening and marked 3D-SWI hypointensity of the ONS, resulting in mass effect upon the CSF space. Optic nerve (ON) hemorrhages were defined by areas of susceptibility artifacts in the ON parenchyma. Superficial siderosis was defined by susceptibility artifact coating the ON. Furthermore, data about post-traumatic deformity of the ONS at the head of the optic nerve were collected.

Results

The average age of the population was 7.9 ± 5.9 months old. The average GCS was 11.8 ± 4.5. The male to female ratio was 7:6. ONS hemorrhages were identified in 69.2% of cases. Superficial siderosis and ON hemorrhages were identified in 38.5 and 76.9% of cases, respectively. 3D-SWI also depicted traumatic deformity of the ONS at the level of the optic nerve head in 10 cases (76.9%). No statistical correlations were identified between RetCam findings and 3D-SWI findings or GCS and ON hemorrhages.

Conclusion

This research shows that dedicated MRI with volumetric SWI of the orbits can depict hemorrhages in the ON, ONS, and ONS injury, in AHT victims.

[Bridging vein injuries in shaken baby syndrome : Forensic-radiological meta-analysis with special focus on the tadpole sign]

Shaken baby syndrome is a common variant of the abusive head trauma in infants and toddlers and is still subject of intensive research. In recent years, a number of radiological studies on the diagnostic and forensic relevance of injured bridging veins were conducted using different imaging modalities. The present article will give an overview on the current state of research in this field and will discuss the forensic implications. The meta-analysis of the seven currently existing studies revealed that injuries of the bridging veins and bridging vein thromboses, respectively, frequently appear as rounded, enlarged, and/or tubular structures. The "tadpole sign" may serve as a valuable tool for the identification of these formations. Especially, T2*/SWI (susceptibility-weighted imaging) sequences allow for good detectability of these lesions and should always be generated when abusive head trauma is suspected. In conclusion, it can be recommended that the presence of radiologically detectable bridging vein injuries should give reason to search for other manifestations of physical child abuse.

The characteristics of brain injury following cerebral venous infarction induced by surgical interruption of the cortical bridging vein in mice

Cerebral venous infarction (CVI) caused by the injury of cortical bridging veins (CBVs), is one of the most serious complications following neurosurgical craniotomy. Different from cerebral artery infarction, this CVI pathological process is more complicated, accompanied by acute venous hypertension, brain edema, cerebral ischemia and hemorrhage in the veins bridged brain area. Therefore, a reliable and stable small animal model is particularly important for the pathological study of CVI induced by surgical CBV interruption (CBVi). A mouse model established by cutting off the right CBVs from bregma to lambda with microsurgical technique is used for the assessment of the pathological process. Adult male mice underwent craniotomy after transection of the parietal skin under anesthesia. The right CBVs were exposed by removing the right skull along the right lateral edge of the sagittal sinus (forming a 4 mm × 3 mm bone window from bregma to lambda) with a drill under the operating microscope. Following the final inspection of the cerebral veins, the CBVs (30% one, 60% two, 10% none) were sacrificed using bipolar coagulation technique. Intracranial pressure (ICP) monitoring, motor function examination, brain edema assessment and brain histopathological observation after perfusion were performed at different time points (6 h, 12 h, 24 h, and 48 h) in the postoperative mice. Cerebral hemisphere swelling, midline shift and subcortical petechial hemorrhage were found on histological sections 6 h after CBVs dissection. The change of ICP was consistent with cerebral edema and peaked at 12 h after surgery, as well as the disruption of the blood-brain barrier assessed by Evans Blue staining. Tissue necrosis, nerve cell loss and monocytes infiltration were also dynamically increased in the postoperative hemispheric cortex. Behavioral tests showed obvious somato- and forelimb-motor dysfunction, and severe somatosensory disorder on the operative mice at 12 h, which were substantially recovered at 48 h. Our study provided a novel mouse model of CVI caused by surgical CBVi that was close to clinical practice, and preliminarily confirmed its pathological process. This model might become an important tool to study the clinical pathology and the molecular mechanism of nerve injury following CVI.

Ocular and Intracranial MR Imaging Findings in Abusive Head Trauma

Abusive head trauma (AHT) is a form of inflicted head injury. AHT is more frequent in 2-year-old or younger children. It is an important cause of neurological impairment and the major cause of death from head trauma in this age group. Brain magnetic resonance imaging allows the depiction of retinal hemorrhages, injured bridging veins, and identifying and localizing extra- and intra-axial bleeds, contusions, lacerations, and strokes. The diagnosis of AHT is a multidisciplinary team effort which includes a careful evaluation of social, clinical, laboratory, and radiological findings. Notwithstanding, the introduction in the current clinical practice of high-resolution techniques is adding forensic evidence to the recognition of AHT.

Parasagittal vertex clots on head CT in infants with subdural hemorrhage as a predictor for abusive head trauma

BACKGROUND

Abusive head trauma (AHT) is the most common cause of subdural hemorrhage (SDH) in infants younger than 12 months old. Clot formation in the parasagittal vertex seen on imaging has been associated with SDH due to AHT. There have been very few studies regarding these findings; to our knowledge, no studies including controls have been performed.

OBJECTIVE

To describe parasagittal vertex clots on head computed tomography (CT) in infants with SDH and AHT compared to patients with SDH and accidental trauma, and to evaluate for parasagittal vertex clots in the absence of SDH in the setting of known accidental head trauma.

MATERIALS AND METHODS

All infants younger than 12 months old with SDH present on CT scan were retrospectively identified from 2004 to 2014. Blinded, independent review of all CT scans for clot formation at the parasagittal vertex was performed by a pediatric neuroradiologist.

RESULTS

Ninety-nine patients were eligible for analysis. Mean age was 4 months. Fifty-seven (57.6%) were male. Fifty-five (55.6%) patients were identified as having AHT and 22 (22.2%) had accidental trauma. Forty-five (81.2%) patients with AHT had parasagittal vertex clots present on CT scan compared to 8 (36.4%) patients with accidental trauma. Compared to patients without parasagittal vertex clots, those with parasagittal vertex clots were more likely to have AHT (66.2% vs. 32.3%, P=0.001), no known mechanism of injury (69.1% vs. 32.3%, P=0.015), retinal hemorrhage (75% vs. 35.5%, P=0.002) and hypoxic-ischemic changes (25% vs. 0%, P=0.002). Patients with parasagittal vertex clots have eight times the odds of AHT compared to patients without parasagittal vertex clots. Age-matched control patients who underwent head CT scan due to a history of accidental head injury without SDH were identified (n=87); no patient in the control group had parasagittal vertex clots.

CONCLUSION

The finding of parasagittal vertex clots on CT scans should raise suspicion for abuse and prompt further investigation, especially in the setting of no known, uncertain or inconsistent mechanism of injury.

[Shaken baby syndrome]

The shaken baby syndrome (SBS) or shaking trauma describes the occurrence of subdural hematoma, retinal hemorrhage and diffuse injury to the brain by vigorous shaking of an infant that has a poor prognosis. Rapid cranial acceleration and deceleration leads to tearing of bridging veins, retinal hemorrhages and diffuse brain injuries. In addition to clinical symptoms, such as irritability, feeding difficulties, somnolence, apathy, seizures, apnea and temperature regulation disorders, vomiting also occurs due to increased intracranial pressure. Milder forms of SBS often go undiagnosed and the number of unreported cases (grey area) is probably much higher. Up to 20 % of patients die within days or weeks due to SBS and survivors often show cognitive deficits and clinical symptoms, such as physical disabilities, impaired hearing, impaired vision up to blindness, epilepsy and mental retardation as well as a combination of these conditions; therefore, prevention is very important.

[Child abuse from a pediatric perspective]

CLINICAL ISSUE

Child abuse is the physical, sexual or emotional maltreatment, or neglect of a child or children. Child maltreatment is defined as any act or series of acts of commission or omission by a parent or other caregiver that results in harm, potential for harm, or threat of harm to a child. Child abuse can occur in a child's home, or in the organizations, schools or communities the child interacts with. There are four major categories of child abuse: neglect, physical abuse, psychological or emotional abuse, and sexual abuse.

DIAGNOSTIC WORK-UP

In child abuse, establishing an early diagnosis is essential. Apart from taking a detailed history and performing a meticulous physical examination, including forensic evaluation as indicated, further diagnostic steps (imaging studies, ophthalmic examination/funduscopy, laboratory studies, etc.) may be warranted.

PRACTICAL RECOMMENDATIONS

In addition to providing acute medical help, longer-term, multidisciplinary interventions have to be put in place in cases of child abuse. This article summarizes the most important facts pertinent to this subject.

In Vivo Demonstration of Traumatic Rupture of the Bridging Veins in Abusive Head Trauma

OBJECTIVE

In victims of abusive head trauma, bridging vein thrombosis is a common finding on magnetic resonance imaging. We aimed to evaluate the utility of high-resolution coronal susceptibility-weighted imaging (SWI) in depicting bridging vein thrombosis as well as to verify the morphology of the bridging vein thrombosis on axial SWI. We additionally analyzed the correlations between bridging vein thrombosis or bridging vein deformation and other magnetic resonance imaging findings that often occur in association with abusive head trauma.

METHODS

Seventeen patients with abusive head trauma were retrospectively evaluated for the presence of thrombosis on axial SWI. The affected veins were localized on coronal SWI, and the strength of association between the presence of bridging vein thrombosis on axial versus high-resolution coronal SWI was determined.

RESULTS

Of 11 patients identified with thrombosis on axial SWI, high-resolution coronal SWI verified bridging vein thrombosis in four individuals (36%). The previously reported "tadpole sign" on axial images did not predict bridging vein thrombosis on coronal SWI (odds ratio = 0.3 [0.02, 5.01], P = 0.538). Volumetric coronal SWI disclosed additional irregularities of the bridging vein walls which was associated with the presence of subdural hematoma on magnetic resonance imaging (P = 0.03), suggesting traumatic injury.

CONCLUSION

Coronal SWI confirmed thrombosis of the bridging veins only in a minority of cases. Diffusely irregular contours of the veins observed on high-resolution coronal SWI was a major finding in our study. Disruption of the normal anatomy of the bridging veins in abusive head trauma further supports the traumatic nature of the disease.

Immobile cerebral veins in the context of positional brain shift: an undescribed risk factor for acute subdural hemorrhage

BACKGROUND

Changes in head position are thought to cause a degree of brain shift in the intracranial cavity. However, little is known on the concurrent shift of the cerebral veins. The present study aimed to investigate the positional shift of the cerebral veins that accompanies brain shift.

METHODS

Sagittal T2-weighted magnetic resonance imaging was performed on 21 consecutive patients lying in the supine and prone positions, using the same sequence. For each patient, imaging data were obtained for the two positions as a pair of images with morphologically best-matched cerebral contours.

RESULTS

The subarachnoid spaces in the parasagittal frontal convexity showed variable reductions related to a postural change from a supine to a prone position, with a mean percent reduction (%Δ) of 17.8 ± 11.7%. Additionally, cerebral cisterns ventral to the brainstem and upper cervical cord were reduced in most patients when lying in a prone position, with a mean %Δ of 16.6 ± 8.7%. In contrast, none of these 130 pairs of identical venous segments located in the parasagittal cerebral convexity showed positional shift. Cadaveric dissections found that the major cortical veins were superficially upheld by the arachnoid membranes.

CONCLUSIONS

The parasagittal major cortical and bridging veins do not seem to show positional shifts. Positional change in the posterior-anterior direction causes a shearing between the frontal cortices and the distributing veins and can be a risk factor for acute subdural hemorrhage, in case of severe head trauma.

Frequency and appearance of hemosiderin depositions after aneurysmal subarachnoid hemorrhage treated by endovascular therapy

INTRODUCTION

It is still unclear how often subarachnoid hemorrhage (SAH) leads to chronic hemosiderin depositions. In this study, we aimed to determine the frequency of chronic hemosiderin depositions after aneurysmal SAH in patients who did not undergo surgery. Furthermore, we analyzed typical MRI patterns of chronic SAH and sought to obtain information on the temporal course of MRI signal changes.

METHODS

We retrospectively analyzed 90 patients who had undergone endovascular treatment for acute aneurysmal SAH. In all patients, initial CT studies and at least one T2*-weighted MRI obtained 6 months or later after SAH were analyzed for the presence and anatomical distribution of SAH or chronic hemosiderin depositions. In total, 185 T2*-weighted MRI studies obtained between 2 days and 148 months after SAH were evaluated (mean follow-up 30.2 months).

RESULTS

On MRI studies obtained later than 6 months after SAH, subpial hemosiderin depositions were found in 50 patients (55.5%). Most frequent localizations were the parenchyma adjacent to the frontal and parietal sulci and the insular cisterns. While the appearance of hemosiderin depositions was dynamic within the first 3 months, no changes were found during subsequent follow-up. MR signal changes were not only conclusive with subarachnoid hemosiderin depositions but in many cases also resembled those that have been associated with cortical hemosiderosis.

CONCLUSIONS

T2*-weighted MRI is an effective means of diagnosing prior SAH. Our study suggests that chronic hemosiderin depositions can be found in a considerable number of patients after a single event of subarachnoid hemorrhage.

Recent progress and future issues in the management of abusive head trauma

Head trauma is the leading cause of death in child abuse cases and one of the important issues in the care of abused children. Since the Child Abuse Prevention Law was enforced in 2000 in Japan, various measures have been taken to prevent child abuse over the following decade. Accordingly, medical research on abusive head trauma (AHT) has advanced, leading to significant progress in the medical diagnosis of AHT. This progress has been brought about by (1) the widespread establishment of child protection teams (CPTs) at core hospitals, (2) the progress in neuroradiological imaging and ophthalmoscopic technologies, and (3) the introduction of postmortem imaging. However, the pathological condition of patients with AHT, particularly that of the diffuse brain swelling type, still remains poorly understood. As a result, no clear treatment strategies for AHT have been developed and no treatment outcomes have been improved to date. The development of new treatment strategies for AHT and the construction of a comprehensive database that supports clinical studies are required in the future.

Imaging of bridging vein thrombosis in infants with abusive head trauma: the "Tadpole Sign"

OBJECTIVES

Abusive head trauma (AHT) in infants is usually diagnosed using a multi-disciplinary approach by investigating the circumstances and identifying morphological indicators, for example, subdural hematomas (SDHs), subdural hygromas (SDHys), retinal haemorrhages and encephalopathy. The present morphological study investigates the incidence, radiological characteristics and non-radiological co-factors of bridging vein thrombosis (BVT) in infants with AHT.

METHODS

From 2002 to 2013, computed tomography (CT) and magnetic resonance imaging (MRI) material of 628 infants aged 0-2 years were analysed retrospectively. If available, medicolegal expert opinions were additionally considered. Cases with SDHs and/or SDHys were identified and systematically evaluated as to the presence and characteristics of BVT.

RESULTS

SDHs and/or SDHys were present in 29 of the 81 cases exhibiting morphological abnormalities in the initial CT. Among these, 11 cases (40%) had BVT (mean age = 5.0 months). BVT could be best depicted in the T1-weighted spin echo and T2*/susceptibility-weighted MRI. In one case, BVT could be depicted indirectly using time-of-flight MR venography. The predominant (73%) BVT shape was found to be tadpole-like ("Tadpole Sign").

CONCLUSIONS

In the absence of appropriate accidental trauma, BVT appears to be a strong indicator of AHT. Therefore, the BVT/Tadpole Sign represents compelling cause to search for other signs of AHT.

KEY POINTS

• BVT is an excellent indicator of AHT in SDH/SDHy cases. • Accidental trauma must be ruled out before diagnosing AHT. • The Tadpole Sign appears to be the most characteristic shape of BVT. • BVT can be depicted using CT, MRI and MR venography. • The Tadpole Sign suggests searching for other signs of AHT.