Diffuse pachymeningeal hyperintensity and subdural effusion/hematoma detected by fluid-attenuated inversion recovery MR imaging in patients with spontaneous intracranial hypotension

Spontaneous intracranial hypotension: Exploring the viability of non-contrast FLAIR as a substitute for contrast-enhanced T1WI in assessing pachymeningeal thickening

PURPOSE

To avoid contrast administration in spontaneous intracranial hypotension (SIH), some studies suggest accepting diffuse pachymeningeal hyperintensity (DPMH) on non-contrast fluid-attenuated inversion recovery (FLAIR) as an equivalent sign to diffuse pachymeningeal enhancement (DPME) on contrast-enhanced T1WI (T1ce), despite lacking thorough performance metrics. This study aimed to comprehensively explore its feasibility.

METHODS

In this single-center retrospective study, between April 2021 and November 2023, brain MRI examinations of 43 patients clinically diagnosed with SIH were assessed using 1.5 and 3.0 Tesla MRI scanners. Two radiologists independently assessed the presence or absence of DPMH on FLAIR and DPME on T1ce, with T1ce serving as a gold-standard for pachymeningeal thickening. The contribution of the subdural fluid collections to DPMH was investigated with quantitative measurements. Using Cohen's kappa statistics, interobserver agreement was assessed.

RESULTS

In 39 out of 43 patients (90.7%), pachymeningeal thickening was observed on T1ce. FLAIR sequence produced an accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 72.1%, 71.8%, 75.0%, 96.6%, and 21.4% respectively, for determining pachymeningeal thickening. FLAIR identified pachymeningeal thickening in 28 cases; however, among these, 21 cases (75%) revealed that the pachymeningeal hyperintense signal was influenced by subdural fluid collections. False-negative rate for FLAIR was 28.2% (11/39).

CONCLUSION

The lack of complete correlation between FLAIR and T1ce in identifying pachymeningeal thickening highlights the need for caution in removing contrast agent administration from the MRI protocol of SIH patients, as it reveals a major criterion (i.e., pachymeningeal enhancement) of Bern score.

The presence of pachymeningeal hyperintensity on non-contrast flair imaging in patients with spontaneous intracranial hypotension

PURPOSE

Traditionally, in the work-up of patients for spontaneous intracranial hypotension, T1 post-contrast imaging is performed in order to assess for pachymeningeal enhancement. The aim of this study is to assess whether pachymeningeal hyperintensity can be identified on a non-contrast FLAIR sequence in these patients as a surrogate sign for pachymeningeal enhancement.

METHODS

The patient cohort was identified from a prospectively maintained database of patients with a clinical diagnosis of intracranial hypotension. Patients who had both a post-contrast T1 sequence brain as well as non-contrast FLAR sequence of the brain were reviewed. Imaging was retrospectively reviewed by three independent neuroradiologists. Each study was assessed for the presence or absence of pachymeningeal hyperintensity on the FLAIR sequence.

RESULTS

From January 2010 to July 2022, 177 patients were diagnosed with spontaneous intracranial hypotension. In total, 121 were excluded as post-contrast imaging was not performed during their work-up. Twenty-four were excluded as the FLAIR sequence was performed after administration of contrast. Six were excluded as there was no pachymeningeal thickening present on T1 post-contrast imaging, although there were other signs of intracranial hypotension. The study group therefore consisted of 26 patients. Pachymeningeal thickening was correctly identified on the non-contrast FLAIR sequence in all patients (100%).

CONCLUSION

Where present, diffuse pachymeningeal hyperintensity can be accurately identified on a non-contrast FLAIR sequence in patients with spontaneous intracranial hypotension. This potentially obviates the need for gadolinium base contrast agents in the work-up of these patients.

MRI Findings after Recent Image-Guided Lumbar Puncture: The Rate of Dural Enhancement and Subdural Collections

BACKGROUND AND PURPOSE

The rate of abnormal intracranial MR imaging findings including subdural collections and dural enhancement after recent lumbar puncture is not known. The purpose of our study was to examine the intracranial MR imaging findings after recent image-guided lumbar puncture.

MATERIALS AND METHODS

Patients who underwent contrast-enhanced MR imaging of the brain within 7 days of a CT-guided lumbar puncture between January 2014 and April 2021 were included. Contrast-enhanced MR images were reviewed for diffuse dural enhancement, morphologic findings of brain sag, dural venous sinus distension, and subdural collections.

RESULTS

Of the 160 patients who met the inclusion criteria, only 6 patients (3.9%) had new diffuse dural enhancement, though none had dural enhancement when the MR imaging was within 2 days of lumbar puncture. All 6 patients with dural enhancement had small, concurrent subdural collections. Two additional patients had subdural collections, for a total of 5.2% of our population.

CONCLUSIONS

Our study is the first to examine intracranial MR imaging after recent lumbar puncture and has 2 key findings: First, 5.2% of patients had small, bilateral subdural collections after recent lumbar puncture, suggesting that asymptomatic subdural collections after recent lumbar puncture are not atypical and do not require further work-up. Additionally, when MR imaging was performed within 2 days of lumbar puncture, none of our patients had diffuse dural enhancement. This argues against the commonly held practice of performing MR imaging before lumbar puncture to avoid findings of dural enhancement, and should not delay diagnostic work-up.

Parenchymal Insults in Abuse—A Potential Key to Diagnosis

Subdural hemorrhage is a key imaging finding in cases of abusive head trauma and one that many radiologists and radiology trainees become familiar with during their years of training. Although it may prove to be a marker of trauma in a young child or infant that presents without a history of injury, the parenchymal insults in these young patients more often lead to the debilitating and sometimes devastating outcomes observed in this young population. It is important to recognize these patterns of parenchymal injuries and how they may differ from the imaging findings in other cases of traumatic injury in young children. In addition, these parenchymal insults may serve as another significant, distinguishing feature when making the medical diagnosis of abusive head injury while still considering alternative diagnoses, including accidental injury. Therefore, as radiologists, we must strive to look beyond the potential cranial injury or subdural hemorrhage for the sometimes more subtle but significant parenchymal insults in abuse.

Spontaneous intracranial hypotension: the role of radiology in diagnosis and management

Spontaneous intracranial hypotension (SIH) is a condition that results from leakage of cerebrospinal fluid (CSF) from the spine, and which typically presents with debilitating orthostatic headache, but can be associated with a wide range of other symptoms. The causes of spontaneous CSF leaks that lead to SIH include dural tears, leaking meningeal diverticula, and CSF-venous fistulas. Imaging plays a central role in the initial diagnosis of SIH and in its subsequent investigation and management. This article reviews the typical neuroimaging manifestations of SIH and discusses the utility of different myelographic techniques for localising spinal CSF leaks as well as the role of image-guided treatment.

Delayed diagnosis of bilateral subdural effusions complicating intracranial hypotension in a patient presenting with post lumbar puncture headache

A 34-year-old woman presented with an unrelenting headache which had been ongoing since discharge from hospital 4 days before. She initially presented 2 weeks earlier with a 7 days history of severe headache, for which she had a CT scan, lumbar puncture and treatment for possible viral meningitis. The headache got worse 4 days after the lumbar puncture. Despite analgesics and bed rest, the headache persisted. A subsequent magnetic imaging scan demonstrated bilateral subdural effusions. She was given supportive treatment, which included advice concerning strict bed rest and analgesia. The headache took several months to abate. A third of patients suffer from post lumbar puncture headaches and this should be explained during informed consenting and post procedure. Not all post lumbar puncture headaches are simple headaches. A post lumbar puncture headache continuing for more than 7-14 days after the procedure requires further investigation to exclude life-threatening intracranial complications.

Computed tomography findings after head injury preceding chronic subdural hematoma

OBJECTIVE

Head CT is sometimes performed immediately after minor head injury; however, which cases develop into chronic subdural hematoma (CSDH) remains unclear. Here, the authors retrospectively reviewed the rare cases of CSDH treated surgically in which early head CT had been performed after the initial head trauma.

METHODS

A total of 172 patients (133 male and 39 female, median age 76 years) underwent surgery for CSDH at Gunma University Hospital between April 2010 and December 2017. Among these patients were 23 who had visited Gunma University Hospital or a nearby hospital and had undergone head CT within 7 days after the initial head trauma. Characteristics of the initial head CT were examined to identify indicators of subsequent CSDH.

RESULTS

Among the 23 CSDH cases (17 male and 6 female, median age 80 years), CT scans were obtained on the day of the initial injury (day 0) in 19 cases (25 sides) and 1-7 days after injury in 12 cases (19 sides); scans were obtained during both periods in 8 cases (12 sides), so that a total of 44 sides were examined. These CT scans were divided into two groups according to when they were obtained; cases in which scans were taken during both periods were included in both groups. Head CT performed on the day of injury showed normal findings in 5 (20%) of 25 sides, thin subdural effusion (SDE) ≤ 6 mm in 16 (64%) of 25 sides, thick SDE > 6 mm in 3 (12%) of 25 sides, and acute subdural hematoma (ASDH) in 1 (4%) of 25 sides. CT from 1-7 days after trauma showed thick SDE in 9 (47%) of 19 sides, thin SDE in 8 (42%) of 19 sides, and ASDH in 2 (11%) of 19 sides. A high-density line in the lateral direction (onion skin-like) was found between the skull and the brain in 9 (35%) of 26 sides with SDE on initial CT 0-7 days after the injury.

CONCLUSIONS

ASDH was not a common cause of CSDH. Head CT at the time of trauma that precedes CSDH often showed SDE. Such SDE that precedes CSDH was often close to the detection limit of CT immediately after the injury but became more apparent from the day after the injury.

Epidural blood patch for spontaneous intracranial hypotension (SIH): a report of two cases

One of the latest diagnoses that need to be considered when evaluating patients with persistent headache is spontaneous (postural) intracranial hypotension (SIH). The diagnosis can be clinched by magnetic resonance imaging (MRI) findings of subdural collections, meningeal enhancement and tonsillar descent. Cerebrospinal fluid leak has been postulated as the cause, and both medical and surgical treatment options have been documented. The treatment of choice is, however, an epidural blood patch. Here we discuss two cases of SIH treated successfully with epidural blood patch.

Imaging of the Spontaneous Low Cerebrospinal Fluid Pressure Headache: A Review

Spontaneous intracranial hypotension (SIH) is a significant cause of chronic, postural headaches. Spontaneous intracranial hypotension is generally believed to be associated with cerebrospinal fluid (CSF) leaks, and these leaks can be posttraumatic, iatrogenic, or idiopathic in origin. An integral part of the management of patients with this condition consists of localizing and stopping the leaks. Radiologists play a central role in the workup of this condition detecting leaks using computed tomography, magnetic resonance imaging, or nuclear imaging. In this article, we briefly review SIH and the various imaging modalities, which can be used to identify and localize a spontaneous CSF leak.

MRI Findings of Spontaneous Intracranial Hypotension: Usefulness of Straight Sinus Distention

OBJECTIVE. Spontaneous intracranial hypotension (SIH) shows various characteristic MRI findings. We evaluated the usefulness of straight sinus distention compared with transverse sinus distention and also evaluated other MRI findings of SIH. MATERIALS AND METHODS. Forty-three consecutive patients (28 female and 15 male patients) treated for SIH and 43 age- and sex-matched control subjects at two institutions from 2012 through 2014 were included in this study. Two reviewers determined whether the transverse sinus distention sign and straight sinus distention sign were present on MRI. Diagnostic performance values and interobserver agreement were calculated. Reviewers also assessed MRI examinations in consensus for the presence of the following findings: pachymeningeal enhancement, subdural effusion or hematoma, enlargement of the pituitary gland, and downward displacement of the brainstem and tonsils. RESULTS. The sensitivity, specificity, and diagnostic accuracy of the transverse sinus distention sign for SIH were 76.7%, 83.7%, and 80.2%, whereas those of the straight sinus distention sign were 79.1%, 95.4%, and 87.2%, respectively. The specificity of the straight sinus distention sign for SIH was significantly higher (p = 0.025) than that of the transverse sinus distention sign. In addition, the straight sinus distention sign showed substantial agreement (κ = 0.79), whereas the transverse sinus distention sign showed moderate agreement (κ = 0.60). The diagnostic accuracy of the presence of either transverse or straight sinus distention (83.7%) was significantly higher than that of pachymeningeal enhancement (80.2%, p = 0.032). CONCLUSION. The straight sinus distention sign could be helpful for the diagnosis of SIH because it has sensitivity comparable to other imaging findings and higher specificity and higher level of interobserver agreement than other imaging findings.

Spontaneous intracranial hypotension and its complications

Spontaneous intracranial hypotension (SIH) is a syndrome that was unknown until the advent of magnetic resonance imaging (MRI). It is a cause of orthostatic headache, which remains underdiagnosed and, rarely, can result in several complications including dural venous sinus thrombosis, subdural hematoma and subarachnoid hemorrhage. Some of these complications are potentially life-threatening and should be recognized promptly, mainly by imaging studies. We reviewed the MRI of nine patients with SIH and describe the complications observed in three of these patients. Two of them had subdural hematoma and one had a dural venous sinus thrombosis detected by computed tomography and MRI. We concluded that MRI findings are of great importance in the diagnosis of SIH and its complications, which often influence the clinical-surgical treatment of the patient.

Diagnostic Imaging and Clinical Features of Intracranial Hypotension - Review of Literature

Intracranial hypotension (IH) is an uncommon, benign, and usually self-limiting condition caused by low cerebrospinal fluid (CSF) pressure, usually due to CSF leakage. The dominant clinical finding is an orthostatic headache. Other common clinical features include fever, nausea, vomiting, and tinnitus.

Magnetic resonance imaging (MRI) plays an important role in the diagnosis and follow-up of patients with IH. Specific MRI findings include intracranial pachymeningeal enhancement, sagging of the brain, pituitary enlargement, and subdural fluid collections.

Intracranial hypotension can mimic other conditions such as aseptic meningitis or pituitary adenomas. Differential diagnosis is important, because misdiagnosis may lead to unnecessary procedures and prolonged morbidity.

Infectious and inflammatory diseases of the central nervous system-the spectrum of imaging findings and differential diagnosis

The infectious and inflammatory diseases of the central nervous system (CNS) including the brain and spine can present with a wide spectrum of clinical symptoms, locations, and appearance. The purpose of this exhibit is to review the different patterns of their presentations, to illustrate their imaging characteristics and techniques, and to discuss their clinical features and pathology so that the correct diagnosis can be made and prompt intervention can be initiated on a timely fashion.

Treatment of Idiopathic Intracranial Hypotension With Tea: A Case Report

INTRODUCTION

The syndrome of spontaneous intracranial hypotension has been increasingly diagnosed since its discovery through magnetic resonance imaging (MRI). It is a rare syndrome that is due to the leakage of cerebrospinal fluid (CSF) from a tear in the dura and can occur at any age, even among adolescents, but is most frequently seen among females in late middle age.

CASE PRESENTATION

Here, we describe a 32-year-old woman with a two-month history of headaches and occasional nausea and vomiting (N/V). MRI without gadolinium was normal, but meningeal enhancement was seen in MRI with gadolinium. The lumbar puncture revealed a low opening pressure. Computed tomography myelography (CT myelography) showed no leakage; Therefore, idiopathic intracranial hypotension was diagnosed. Treatment was started using tea, and the patient's headache got significantly better in about a day.

CONCLUSIONS

Conservative therapy, such as bed rest and caffeine treatment with eight cups of tea daily, yielded a significant improvement in our patient. Effectively, the patient constitutes a case of idiopathic intracranial hypotension due to undetectable CSF leakage or hyper-absorption, with good response to conservative management through tea-drinking. Further investigations with an appropriate sample size are needed in order to confirm this intervention in the treatment of idiopathic intracranial hypotension.

Sex- and Age-Related Differences in the Clinical and Neuroimaging Characteristics of Patients With Spontaneous Intracranial Hypotension: A Records Review

BACKGROUND

The significance of sex- and age-related differences in the clinical course of spontaneous intracranial hypotension (SIH) was investigated.

METHODS

We retrospectively studied 40 consecutive patients (female:male = 28:12, median age 41.5 years) treated under clinical diagnoses of SIH satisfying the International Classification of Headache Disorders 3rd edition criteria, including 37 patients (92.5%) with diffuse pachymeningeal enhancement. The patients were divided into two groups by age and sex, and the clinical and neuroimaging findings in each group were investigated.

RESULTS

Acute onset (female:male = 82.1%:50.0%, P = .042), severe headache (75.0%:41.7%, P = .045) occurred with higher frequency in females than in males, and SDH occurred with lower frequency in females than in males (28.6%:75.0%, P = .006). Duration until the consultation (2:14 days, P = .022), SDH thickness (0:7.1 mm, P = .001), and iter displacement (1.6:7.1 mm, P = .004) was greater in males. Acute onset (Younger [≤40 years]: older [>40 years] = 94.1%:56.5%, P = .012), occurred with higher frequency in younger patients, and duration until the consultation (1:5 days, P = .001), frequency of SDH (17.7%:60.9%, P = .010), SDH thickness (0:5.9 mm, P = .003), in older patients. All nine patients with thunderclap headache were female, with median age of 37 years.

CONCLUSIONS

More severe clinical symptoms with acute onset were observed in females and younger patients of SIH. Comparatively rare subdural hygroma/hematoma on magnetic resonance imaging might result from the shorter duration to diagnosis in females and younger patients.

KEY WORDS

spontaneous intracranial hypotension, sex, age, magnetic resonance imaging, thunderclap headache.

Prevalence of and Factors Associated with Dural Thickness in Patients with Mild Cognitive Impairment and Alzheimer's Disease

BACKGROUND AND PURPOSE

We performed this study to evaluate the prevalence of and factors associated with dural thickening in patients with mild cognitive impairment and Alzheimer's disease.

METHODS

Alzheimer's disease neuroimaging initiative participants with axial FLAIR sequence magnetic resonance imaging (MRI) images were analyzed. Dural thickness was defined by a linear strip of hyperintense tissue signal along the dura mater observed in at least two different images without evidence of leptomeningeal involvement.

RESULTS

Dural thickening was seen in 83 (34%) of 242 persons analyzed (mean age [±SD] 74±7 years: 150 were men) with either mild cognitive impairment or Alzheimer's disease. The mini mental score was not different in persons with (26±0.3) and without (26±0.2) dural thickening (p = 0.6). The proportion of patients with moderate or severe cognitive impairment (defined by mini mental status score) was similar at baseline and at 12-month evaluations. The rates of annual progression according to Alzheimer's disease assessment scale (p = 0.06) and clinical dementia scale (p = 0.001) were higher in persons without dural thickening. The annual rate of volume loss in entorhinal cortex was higher among persons with dural thickening.

CONCLUSIONS

We found relatively high prevalence of dural thickening in patients with mild cognitive impairment and Alzheimer's disease.

Postoperative intraspinal subdural collections after pediatric posterior fossa tumor resection: incidence, imaging, and clinical features

BACKGROUND AND PURPOSE

Postoperative intraspinal subdural collections in children after posterior fossa tumor resection may temporarily hinder metastasis detection by MR imaging or CSF analysis, potentially impacting therapy. We investigated the incidence, imaging and clinical features, predisposing factors, and time course of these collections after posterior fossa tumor resection.

MATERIALS AND METHODS

Retrospective review of postoperative spine MRI in 243 children (5.5 ± 4.6 years of age) from our clinical data base postresection of posterior fossa tumors from October 1994 to August 2010 yielded 37 (6.0 ± 4.8 years of age) subjects positive for postoperative intraspinal subdural collections. Their extent and signal properties were recorded for postoperative (37/37), preoperative (15/37), and follow-up spine (35/37) MRI. Risk factors were compared with age-matched internal controls (n = 37, 5.9 ± 4.5 years of age). Associations of histology, hydrocephalus and cerebellar tonsillar herniation, and postoperative intracranial subdural collections with postoperative intraspinal subdural collections were assessed by the Fisher exact test or χ(2) test. The association between preoperative tumor volume and postoperative intraspinal subdural collections was assessed by the Wilcoxon rank sum test.

RESULTS

The overall incidence of postoperative intraspinal subdural collections was 37/243 (15.2%), greatest ≤7 days postoperatively (36%); 97% were seen 0-41 days postoperatively (12.9 ± 11.0 days). They were T2 hyperintense and isointense to CSF on T1WI, homogeneously enhanced, and resolved on follow-up MR imaging (35/35). None were symptomatic. They were associated with intracranial subdural collections (P = .0011) and preoperative tonsillar herniation (P = .0228).

CONCLUSIONS

Postoperative intraspinal subdural collections are infrequent and clinically silent, resolve spontaneously, and have a distinctive appearance. Preoperative tonsillar herniation appears to be a predisposing factor. In this series, repeat MR imaging by 4 weeks documented improvement or resolution of these collections in 88%.

Spontaneous Intracranial Hypotension: Recommendations for Management

A literature search found no clinical trials or guidelines addressing the management of spontaneous intracranial hypotension (SIH). Based on the available literature and expert opinion, we have developed recommendations for the diagnosis and management of SIH. For typical cases, we recommend brain magnetic resonance (MR) imaging with gadolinium to confirm the diagnosis, and conservative measures for up to two weeks. If the patient remains symptomatic, up to three non-directed lumbar epidural blood patches (EBPs) should be considered. If these are unsuccessful, non-invasive MR myelography, radionuclide cisternography, MR myelography with intrathecal gadolinium, or computed tomography with myelography should be used to localize the leak. If the leak is localized, directed EPBs should be considered, followed by fibrin sealant or neurosurgery if necessary. Clinically atypical cases with normal brain MR imaging should be investigated to localize the leak. Directed EBPs can be used if the leak is localized; non-directed EBPs should be used only if there are indirect signs of SIH.

Spontaneous intracranial hypotension with magnetic resonance localisation of spinal cerebrospinal fluid leak

To increase the awareness of spontaneous intracranial hypotension (SIH), we report in this paper a middle-aged woman who presented with an intractable headache that worsened in sitting and standing positions (a postural headache). Magnetic resonance imaging (MRI) of the spine demonstrated a cerebrospinal fluid (CSF) leak at the level of the cervical spine, in addition to typical features in a brain MRI, including symmetrical subdural collections, circumferential dural enhancement and features of midbrain sagging. The patient underwent a surgical repair of the cervical CSF leak which resulted in a dramatic symptomatic improvement that was confirmed by follow-up imaging.

Intracranial hypotension with multiple complications: an unusual case report

Background. Undiagnosed intracranial hypotension can result in several complications including subdural hematoma (SDH), subarachnoid hemorrhage (SAH), dural venous sinuses thrombosis (CVT), cranial nerve palsies, and stupor resulting from sagging of the brain. It is rare to see all the complications in one patient. Furthermore, imaging of the brain vasculature may reveal incidental asymptomatic small aneurysms. Given the combination of these imaging findings and a severe headache, the patients are often confused to have a primary subarachnoid hemorrhage. Case Report. We present a patient with spontaneous intracranial hypotension (SIH) who had an incidental ophthalmic artery aneurysm on MR imaging, and this presentation led to coiling of the aneurysm. The key aspect in the history "postural headaches" was missed, and this led to life threatening complications and unnecessary interventions. Revisiting the history and significant improvement in symptoms following an epidural blood patch resulted in the diagnosis of SIH. Conclusion. We strongly emphasize that appropriate history taking is the key in the diagnosis of SIH and providing timely treatment with an epidural blood patch could prevent potentially life threatening complications.

Cerebral venous sinus thrombosis complicated by subdural hematomas: Case series and literature review

Background:

Cerebral venous sinus thrombosis (CVST) can cause elevated intracranial pressure, hemorrhagic venous infarct, and cortical subarachnoid hemorrhage. We present a case series and literature review to illustrate that CVST can also present with subdural hematoma (SDH).

Case Description:

Chart review was completed on a retrospective case series of CVST with spontaneous SDH. We also conducted a literature search. Over a 6 year interval, three patients with CVST and SDH were admitted to the neurointensive care unit. A 38-year-old woman had both SDH and a hemorrhagic venous infarct associated with a transverse sinus thrombosis. She was managed conservatively with long-term anticoagulation. A 68-year-old woman presented with an acute SDH requiring craniotomy and a thrombosed cortical vein was noted intraoperatively. Computed tomography venography showed thrombosis of the superior sagittal sinus. She had polycythemia vera with the V617 Jak2 gene mutation and was managed with aspirin and hydroxyurea. A 60-year-old male had recurrence of a spontaneous convexity SDH requiring reoperation. Neuroimaging identified ipsilateral transverse sinus thrombosis with retrograde flow into the opposite sinus. Manometry demonstrated elevated venous pressures and these normalized after thrombectomy. Angiography performed after endovascular treatment demonstrated a normal venous drainage pattern. There have been limited reports of SDH complicating CVST in the literature.

Conclusion:

This case series and literature review demonstrates that CVST can also present with spontaneous SDH with or without associated venous infarctions. Treatment must be individualized. This is the first published description of endovascular thrombectomy for recurrent symptomatic SDH due to CVST.

Reversal in the diameter of the superior ophthalmic vein after an epidural blood patch in a case of spontaneous intracranial hypotension

Spontaneous intracranial hypotension (SIH) is caused by single or multiple cerebrospinal fluid (CSF) leaks in the spine with the prototypical symptom of postural headache. One of the characteristic MRI features in SIH is intracranial venous engorgement. This report presents a case of SIH with engorgement of the bilateral superior ophthalmic veins (SOVs) which resume their normal diameters by the third day of successful epidural blood patches (EBPs). We define this phenomenon as the "reversal of the SOV" sign.

Childhood moyamoya disease and moyamoya syndrome: a pictorial review

Moyamoya disease is an uncommon chronic cerebrovasculopathy, characterized by progressive stenosis of the terminal portion of the internal carotid artery and its main branches, in association with the development of compensatory collateral vessels at the base of the brain. The etiology is unknown, and was originally considered exclusive to East Asia, with particular prevalence in Japan. Moyamoya disease is increasingly diagnosed throughout the world, and represents an important cause of childhood stroke in Western countries. In some cases, similar angiographic features are evident in children with other medical conditions, such as sickle cell disease and Down syndrome. In these instances, the term "moyamoya syndrome" is used. Diagnosing the vasculopathy, excluding possible associated conditions, and planning treatment and follow-up imaging comprise important aspects of clinical management. We review the key imaging features of childhood moyamoya disease and syndrome, present examples of its associations, and discuss new neuroradiologic methods that may be useful in management.

Cranial nerve III palsy resulting from intracranial hypotension caused by cerebrospinal fluid leak after paraspinal tumor resection: etiology and treatment options

BACKGROUND CONTEXT

Intracranial hypotension typically occurs spontaneously. Acquired or secondary intracranial hypotension is less common but has been reported after spinal procedures, such as lumbar puncture. Cranial nerve (CN) III palsy is a rare sequela of intracranial hypotension. There are currently no established or standard interventions to treat intracranial hypotension.

PURPOSE

To describe a case of delayed CN III palsy resulting from intracranial hypotension because of a spinal cerebrospinal fluid (CSF) leak occurring during resection of a paraspinous tumor.

STUDY DESIGN

Case report.

METHODS

A 41-year-old woman underwent resection of a large thoracic schwannoma complicated by dural tear. Postoperatively, the patient was neurologically normal. She subsequently became acutely unresponsive and required reintubation. She awakened with intermittent headaches and was noted to have a right ptosis, which progressed to a complete right CN III palsy.

RESULTS

Initial head computed tomography showed evidence of a small, right-sided subdural hematoma. Magnetic resonance imaging (MRI) of the brain showed diffuse leptomeningeal enhancement and crowding of the foramen magnum consistent with intracranial hypotension. The patient's symptoms were treated successfully with flat bed rest. She fully recovered by time of discharge and at 6-month follow-up was neurologically normal.

CONCLUSIONS

Spinal surgery complicated by CSF leak is a potential cause of intracranial hypotension. Although most commonly associated with positional headaches, intracranial hypotension can cause uncommon symptoms, including acute mental status changes and CN deficits. Symptoms highly suspicious for intracranial hypotension accompanied by MRI of the brain are important for establishing a diagnosis of intracranial hypotension. Conservative treatment should be considered before attempting invasive intervention. As in the case presented, simple bed rest was a successful treatment option.

Imaging of the meninges and the extra-axial spaces

The separate meningeal layers and extraaxial spaces are complex and can only be differentiated by pathologic processes on imaging. Differentiation of the location of such processes can be achieved using different imaging modalities. In this pictorial review we address the imaging techniques, enhancement and location patterns, and disease spread that will promote accurate localization of the pathology, thus improving accuracy of diagnosis. Typical and unusual magnetic resonance (MR), computed tomography (CT), and ultrasound imaging findings of many conditions affecting these layers and spaces are described.

The contribution of imaging in diagnosis, preoperative assessment, and follow-up of moyamoya disease

The aim of this review was to evaluate the imaging tools used in diagnosis and perioperative assessment of moyamoya disease, with particular attention to the last decade.