Dystrophic intracranial calcification: CT evidence of 'cerebral steal' from arteriovenous malformation

Pediatric intracranial calcified arteriovenous malformation: A case report

Background:

Brain arteriovenous malformations (AVMs) are intracranial lesions that consist of a complex tangle of abnormal blood vessels. They can occasionally become hard and calcified. This may render these lesions difficult to resect and lead to neurological complications. There are very few reported cases of calcified brain AVMs in the literature.

Case Description:

We report the case of an 11-year-old patient who presented with headaches and seizures exacerbated in the past 3 months. Preoperative imaging confirmed a large, right parasagittal AVM, with significant internal calcifications seen on the computed tomography angiogram. We performed a successful microsurgical resection of the calcified AVM and confirmed the diagnosis on histopathological analysis.

Conclusion:

Dense internal calcifications within AVMs are a clinical rarity and can be challenging cases for microsurgical resection.

Intracranial calcification in venous congestion

Background

Intracranial calcification is a common finding on brain imaging which can be non-specific. The calcification can be physiological or pathological. Likewise, subcortical calcification is a non-specific finding on non-contrast-enhanced computed tomography. This could be secondary to multiple underlying diseases such as Sturge-Weber syndrome, tuberous sclerosis, Fahr disease, post-chemoradiotherapy change, and metabolic disorders secondary to parathyroid or thyroid gland abnormalities. On the other hand, subcortical calcification secondary to arteriovenous malformation and dural venous fistula are uncommon findings. We report two cases with subcortical calcification secondary to these vascular malformations. We aim to highlight the importance of recognising subcortical calcification as one of the possible imaging appearances of dural venous fistula and arteriovenous malformation.

Case presentation

We report two cases, whom were a 45-year-old lady and a 20-year-old man, with subcortical calcification on non-contrast-enhanced computed tomography, which were later confirmed to be secondary to chronic venous congestion as the results of dural venous fistula and arteriovenous malformation, respectively. Both patients underwent magnetic resonance imaging of the brain and digital substraction angiography to confirm the diagnosis. Subsequently, both patients were offered embolisation with the 45-year-old lady opting for conservative management and the 20-year-old man waiting for the procedure, at the time of writing.

Conclusion

Venous congestion secondary to intracranial vascular malformation is an important differential diagnosis for extensive subcortical and basal ganglia calcification. Knowledge on the possibility of vascular malformation to present with subcortical calcification is crucial to avoid misdiagnosis and mismanagement of the patients.

Intracranial Gorgon: Surgical Case Report of a Large Calcified Brain Arteriovenous Malformation

Patient: Male, 55-year-old

Final Diagnosis: Right frontal arteriovenous malformation, partially calcified • multiple generalised epileptic seizures • chronic headache

Symptoms: Epilectic seizure • headache

Medication: —

Clinical Procedure: Neurosurgical resection of the right frontal AVM

Specialty: Neurosurgery

Epidemiology, genetics, pathophysiology, and prognostic classifications of cerebral arteriovenous malformations

Arteriovenous malformations (AVMs) are vascular deformities involving fistula formation of arterial to venous structures without an intervening capillary bed. Such anomalies can prove fatal as the high arterial flow can disrupt the integrity of venous walls, thus leading to dangerous sequelae such as hemorrhage. Diagnosis of these lesions in the central nervous system can often prove challenging as intracranial AVMs represent a heterogeneous vascular pathology with various presentations and symptomatology. The literature suggests that most brain AVMs (bAVMs) are identified following evaluation of the etiology of acute cerebral hemorrhage, or incidentally on imaging associated with seizure or headache workup. Given the low incidence of this disease, most of the data accrued on this pathology comes from single-center experiences. This chapter aims to distill the most important information from these studies as well as examine meta-analyses on bAVMs in order to provide a comprehensive introduction into the natural history, classification, genetic underpinnings of disease, and proposed pathophysiology. While there is yet much to be elucidated about AVMs of the central nervous system, we aim to provide an overview of bAVM etiology, classification, genetics, and pathophysiology inherent to the disease process.

Diffuse Proliferative Cerebral Angiopathy: A case report and review of the literature

Diffuse proliferative cerebral angiopathy is a distinct entity from cerebral arterio-venous malformations; characterized by multiple small arterial feeders and draining veins with normal brain parenchyma seen in-between the abnormal vessels. It is usually seen in younger age group. Here we report a case of diffuse cerebral proliferative angiopathy in a 78-year-old female patient along with discussion of the neuro-imaging findings and review of the literature. It is important to recognize this entity to avoid aggressive surgery or intervention and thus preventing permanent damage to the normal intermingled brain tissue.

Calcifications associated with pediatric intracranial arterial aneurysms: incidence and correlation with pathogenetic subtypes

BACKGROUND AND PURPOSE

Little is known about calcifications associated with pediatric intracranial arterial aneurysms (IAA). We sought to characterize calcifications associated with pediatric IAA according to aneurysm pathogenetic subtype.

MATERIALS AND METHODS

Patients with IAA less than 20 years of age were retrospectively identified. Three fellowship-trained neuroradiologists independently reviewed each patient's CT studies for calcifications of the parent artery or aneurysm. Aneurysmal calcification (ANC) was correlated with characteristics of the patient (age, sex) and aneurysm pathogenetic subtype, size, morphology, rupture status, and location.

RESULTS

Thirty-three patients (mean age 10 years) with 43 IAA were analyzed. There were no parent artery calcifications. Nine IAA were calcified. IAA in children with non-hemodynamic risk factors (arteriopathy, trauma, infection, tumor) were more commonly calcified than idiopathic IAA (p = 0.029). More than one third of the pediatric IAAs in this group (arteriopathy, infection trauma, tumor) were calcified. IAA ≥ 10 mm were more likely to be calcified (p = 0.03). IAA that were ruptured at presentation were less likely to be calcified (p = 0.03). ANC was not significantly associated with patient age (≤10 years vs. >10 years), sex, morphology (fusiform vs. saccular) or location (anterior vs. posterior circulation).

CONCLUSION

Aneurysmal but not parent artery calcifications are associated with a significant minority of pediatric IAA. Pediatric ANCs are associated with underlying non-hemodynamic vascular risk factors (arteriopathy, infection, trauma, and tumor), size ≥10 mm and non-hemorrhagic presentation.

Dural arteriovenous fistula involving an isolated sinus treated using transarterial onyx embolization

The authors present a case of isolated dural arteriovenous fistula (DAVF) in the transverse sinus, which developed six years after microvascular decompression caused by hemifacial spasm via suboccipital craniectomy. The lesion was successfully treated by transarterial embolization using Onyx. We reviewed the related radiologic and therapeutic features of DAVF involving an isolated sinus and described the feasibility of the use of Onyx.

Intracranial Calcifications

Brain calcifications are a common radiographic finding. The pathogenesis is diverse and ranges from benign physiological calcifications to a variety of pathological disorders. Whereas certain calcifications are considered an incidental finding, their presence can sometimes be crucial in making a specific diagnosis. Several pathological conditions affecting the brain parenchyma are associated with calcifications and their recognition and location might help in narrowing the differential. Knowledge of physiological calcifications is essential to avoid misinterpretation. This review illustrates a broad spectrum of CNS disorders associated with calcifications, and tries to highlight the salient radiological findings.

Large vascular malformation in a child presenting with vascular steal phenomenon managed with pial synangiosis

The management of large and giant arteriovenous malformations (AVMs) in patients presenting with nonhemorrhagic neurological deficits secondary to vascular steal phenomenon is challenging and controversial. In many cases, large AVMs cannot be completely excised or cured, leaving patients with residual or partially treated AVMs, the natural history of which is unknown. Additionally, large, diffuse vascular malformations with multiple, small feeders, slow flow, or so-called cerebral proliferative angiopathy represent a related but distinct clinical and angiographic entity that may require a different therapeutic approach than traditional brain AVMs. The current management of children with other conditions of chronic cerebral hypoperfusion, such as moyamoya disease, involves consideration of surgical revascularization to enhance blood flow to the compromised hemisphere. Here, the authors present the case of a young child with a large thalamic vascular malformation who presented with clinical and radiological features of vascular steal and ischemia. In an effort to augment flow to the hypoperfused brain and protect against future ischemia, the authors treated the child with unilateral pial synangiosis. At 12 months, postoperative angiography demonstrated robust neovascularization, and the child has not sustained any further ischemic events. The authors discuss concept of vascular malformation-related hypoperfusion and the utility of indirect revascularization for inoperable vascular malformations presenting with ischemic symptoms.

Unilateral calcification of the caudate and putamen: association with underlying developmental venous anomaly

Stenosis of a DVA may result in chronic venous ischemia. We present 6 patients (3 men, 3 women; age range, 30-79 years; mean age, 53 years) with unilateral calcification of the caudate and putamen on noncontrast CT. This calcification typically spared the anterior limb of the internal capsule. No patient presented with symptoms referable to the basal ganglia or had an underlying metabolic disorder or other process associated with calcium deposition. All patients subsequently underwent gadolinium-enhanced MR imaging and/or CTA or conventional angiography demonstrating the presence of an adjacent DVA. We hypothesize that chronic venous ischemia in the drainage territory of the DVA causes the abnormal mineralization. Greater recognition of this entity will prevent misinterpretation of this finding as acute hemorrhage and will prevent unnecessary and sometimes invasive evaluation in such patients. Furthermore, this entity should be considered in the differential diagnosis of unilateral basal ganglia hyperattenuation.

Cerebral arteriovenous malformations. Part 2: physiology

Object

The scientific understanding of the nature of arteriovenous malformations (AVMs) in the brain is evolving. It is clear from current work that AVMs can undergo a variety of phenomena, including growth, remodeling, and/or regression—and the responsible processes are both molecular and physiological. A review of these complex processes is critical to directing future therapeutic approaches. The authors performed a comprehensive review of the literature to evaluate current information regarding the genetics, pathophysiology, and behavior of AVMs.

Methods

A comprehensive literature review was conducted using PubMed to reveal the angioarchitecture and cerebral hemodynamics of AVMS as they relate to lesion development.

Results

Feeding artery pressures, brain AVM compartmentalization, venous drainage, flow phenomena, and vascular steal are discussed.

Conclusions

The dynamic nature of brain AVMs is at least in part attributable to hemodynamic and flow-related phenomena. These forces acting on an evolving structure are critical to understanding the challenges in endovascular and surgical therapy. As knowledge in this field continues to progress, the natural history and predicted behavior of these AVMs will become more clearly elucidated.

Intracerebral atypical calcification in nongalenic pial arteriovenous fistula: a case report

Nongalenic intradural arteriovenous fistulas, although uncommon, are clinically important. Choosing the appropriate therapeutic approach has been a controversial issue within the last decade.

A 15-year-old male was presented with a calcified nongalenic arteriovenous fistula in the left parietal region, supplied by the left middle cerebral artery, and draining into the left lateral sinus. The patient was managed surgically with traditional clipping the feeder artery, along with piecemeal resection of the huge calcified mass. Although endovascular methods may be the treatments of choice in similar cases, in such huge calcified lesion, non-amenable to endovascular occlusion, open surgery seems to be preferred.

Association of cerebral arteriovenous malformations and spontaneous occlusion of major feeding arteries: clinical and therapeutic implications

OBJECTIVE

The spontaneous occlusion of a cerebral arteriovenous malformation (AVM) occurs rarely. Occlusion of a parent artery feeding the AVM is even more rare, and its incidence is unknown. We undertook this study to determine the incidence of occlusion of a major artery feeding an AVM and to recommend a management strategy for such an AVM.

METHODS

We identified AVMs associated with an occluded artery by performing a retrospective angiographic analysis of 500 patients with AVMs who presented to Henry Ford Hospital from 1976 to 1998.

RESULTS

A review of the angiograms revealed that 7 (1.4%) of 500 patients with an AVM had occlusion of one or more major arteries feeding the nidus. In four patients, an internal carotid artery and its bifurcation were occluded; in two patients, the M1 segment of the middle cerebral artery was occluded, and in one patient, a vertebral artery was occluded. Pial collaterals and/or a moyamoya pattern of anastomoses developed in all patients, with the exception of one who had vertebral artery occlusion. Five patients underwent definitive treatment: one received radiosurgery, and four underwent surgical excision. One of the surgically treated patients died of complications from excessive blood loss and coagulopathy, but the other three had no postoperative complications.

CONCLUSION

The occlusion of a major artery feeding an AVM occurs rarely (1.4%). These AVMs are moderate to large in size (>3 cm). To prevent collateral flow-related complications of cortical "steal" and hemorrhage, as well as the usual risk of hemorrhage from the AVM itself, surgical management should be considered for these AVMs.

Extensive intracranial calcification secondary to hypoxia, presenting with dyspraxic gait

The imaging appearances of a case of extensive intracranial calcification presenting with dyspraxic gait are described. Computed tomography showed bilateral calcification in the anterior, posterior and central watershed areas and in the basal ganglia. It is believed that the changes are secondary to previous hypoxaemia and hypotension, and that subsequent development of the symptoms is due to calcification in the dystrophic tissue.

Clinical and radiological evaluation of angiographically occult, calcified intracranial vascular malformation. Case report

In this study, we present an angiographically occult, calcified intracranial vascular malformation. This lesion is rare and has some therapeutic difficulties and different approaches by authors. In this article, we also discuss the clinical, radiological characteristic features of this lesion. We pay attention on the totally calcified malformation.

Arteriovenous fistulas of the brain and the spinal cord

Arteriovenous (AV) fistulas of cerebral and spinal arteries are characterized angiographically by an immediate AV transition without a capillary bed or "nidus" as occurs in AV malformations (AVM's). The clinical presentation, morphology, radiology, and treatment of 12 patients with cerebral AV fistulas and of 12 patients with spinal AV fistulas are reviewed. In the patients with cerebral lesions, headache and seizure disorders were the most common presentations followed by subarachnoid hemorrhage, cardiac failure, progressive neurological dysfunction, and incidental detection on prenatal ultrasound study. In patients with spinal AV fistulas, weakness and sensory disturbance in the lower extremities were the most frequent clinical presentations followed by back pain, disturbances of micturition, and grand mal seizure. The etiology of the symptom complex produced by AV fistulas in each of these locations differed, with venous hypertension being important in spinal cord lesions. Of the patients with cerebral lesions, nine had a single AV fistula, one had two fistulas, and two had multiple fistulas. An AVM was observed in five patients with fistulas (two large, three small). Nine patients exhibited extramedullary AV fistulas of the spine, of whom eight had a single fistula and one had three fistulas; three patients had intramedullary spinal AV fistulas. An arterial aneurysm was found in association with two fistulas, one cerebral and one spinal. Venous ectasias or varices, frequently exhibiting mural calcification, were observed to be prominent in all AV fistulas involving cerebral arteries and in two involving spinal arteries. The location and size of the venous complexes reflected the diameter of the fistula. In addition to conventional imaging techniques (cerebral angiography, computerized tomography, and magnetic resonance (MR) imaging), MR angiography was a helpful adjunct in the evaluation of fistulas. Treatment strategies employed for AV fistulas in both locations included open surgical and endovascular procedures, frequently used in combination. A satisfactory outcome was observed in all patients.