Lateral Spinal CSF Leaks in Patients with Spontaneous Intracranial Hypotension: Radiologic-Anatomic Study of Different Variants.

BACKGROUND AND PURPOSE: Spinal CSF leaks cause spontaneous intracranial hypotension. Several types of leaks have been identified, and one of these types is the lateral dural tear. Performing myelography with the patient in the decubitus position allows precise characterization of these leaks. The purpose of the current study was to describe the different variants of spontaneous lateral CSF leaks. MATERIALS AND METHODS: This retrospective cohort study included a consecutive group of patients with spontaneous intracranial hypotension and lateral CSF leaks who underwent digital subtraction myelography in the decubitus position and underwent surgery to repair the CSF leak between July 2018 and June 2023. RESULTS: The mean age of the 53 patients (37 women and 16 men) was 35.5 years. Three different variants of lateral CSF leak could be identified. Forty-nine patients (92.5%) had a lateral dural tear associated with the nerve root sleeve. The dural tear was at the axilla of the nerve root sleeve in 36 patients (67.9%) and at the shoulder in 13 patients (24.5%). Four patients (7.5%) had a lateral dural tear at the level of the pedicle that was not associated with the nerve root sleeve. Findings on digital subtraction myelography were concordant with intraoperative findings in all patients. An extradural CSF collection was seen in all patients with a lateral dural tear associated with the nerve root sleeve but in only 2 of the 4 patients with the pedicular variant of a lateral dural tear. CONCLUSIONS: We identified 3 variants of spontaneous lateral dural tears. Most lateral dural tears are associated with extradural CSF collections and arise from either the axilla (67.9%) or the shoulder (24.5%) of the nerve root sleeve. Lateral dural tears at the level of the pedicle (7.5%) not associated with the nerve root sleeve are uncommon and may require specialized imaging for their detection.

Optic Nerve Sheath MR Imaging Measurements in Patients with Orthostatic Headaches and Normal Findings on Conventional Imaging Predict the Presence of an Underlying CSF-Venous Fistula.

BACKGROUND AND PURPOSE: Spontaneous spinal CSF leaks typically cause orthostatic headache, but their detection may require specialized and invasive spinal imaging. We undertook a study to determine the value of simple optic nerve sheath MR imaging measurements in predicting the likelihood of finding a CSF-venous fistula, a type of leak that cannot be detected with routine spine MR imaging or CT myelography, among patients with orthostatic headache and normal conventional brain and spine imaging findings. MATERIALS AND METHODS: This cohort study included a consecutive group of patients with orthostatic headache and normal conventional brain and spine imaging findings who underwent digital subtraction myelography under general anesthesia to look for spinal CSF-venous fistulas. RESULTS: The study group consisted of 93 patients (71 women and 22 men; mean age, 47.5 years; range, 17-84 years). Digital subtraction myelography demonstrated a CSF-venous fistula in 15 patients. The mean age of these 8 women and 7 men was 56 years (range, 23-83 years). The mean optic nerve sheath diameter was 4.0 mm, and the mean perioptic subarachnoid space was 0.5 mm in patients with a CSF-venous fistula compared with 4.9 and 1.2 mm, respectively, in patients without a fistula (P < .001). Optimal cutoff values were found at 4.4 mm for optic nerve sheath diameter and 1.0 mm for the perioptic subarachnoid space. Fistulas were detected in about 50% of patients with optic nerve sheath diameter or perioptic subarachnoid space measurements below these cutoff values compared with <2% of patients with optic nerve sheath diameter or perioptic subarachnoid space measurements above these cutoff values. Following surgical ligation of the fistula, optic nerve sheath diameter increased from 4.0 to 5.3 mm and the perioptic subarachnoid space increased from 0.5 to 1.2 mm (P < .001). CONCLUSIONS: Concerns about a spinal CSF leak should not be dismissed in patients with orthostatic headache when conventional imaging findings are normal, and simple optic nerve sheath MR imaging measurements can help decide if more imaging needs to be performed in this patient population.

Postoperative Spinal Cerebrospinal Fluid-Venous Fistulas Associated With Dural Tears in Patients With Intracranial Hypotension or Superficial Siderosis-A Digital Subtraction Myelography Study.

BACKGROUND: Postoperative spinal cerebrospinal fluid (CSF) leaks are common but rarely cause extensive CSF collections that require specialized imaging to detect the site of the dural breach. OBJECTIVE: To investigate the use of digital subtraction myelography (DSM) for patients with extensive extradural CSF collections after spine surgery. METHODS: A retrospective review was performed to identify a consecutive group of patients with extensive postoperative spinal CSF leaks who underwent DSM. RESULTS: Twenty-one patients (9 men and 12 women) were identified. The mean age was 46.7 years (range, 17-75 years). The mean duration of the postoperative CSF leak was 3.3 years (range, 3 months to 21 years). MRI showed superficial siderosis in 6 patients. DSM showed the exact location of the CSF leak in 19 (90%) of the 21 patients. These 19 patients all underwent surgery to repair the CSF leak, and the location of the CSF leak could be confirmed intraoperatively in all 19 patients. In 4 (19%) of the 21 patients, DSM also showed a CSF-venous fistula at the same location as the postoperative dural tear. CONCLUSION: In this study, DSM had a 90% detection rate of visualizing the exact site of the dural breach in patients with extensive postoperative spinal CSF leaks. The coexistence of a CSF-venous fistula in addition to the primary dural tear was present in about one-fifth of patients. The presence of a CSF-venous fistula should be considered if CSF leak symptoms persist in spite of successful repair of a durotomy.

Prospective Evaluation of Incidental Pituitary Imaging Findings in the Sella Turcica.

PURPOSE: Reported rates of incidentally discovered pituitary sellar lesions vary widely, at least in part because of the inadvertent inclusion of patients with a history suspicious for a pituitary disorder. We prospectively evaluated the incidence of truly incidental sellar findings detected on imaging at a large academic medical center. METHODS: Deidentified data were extracted from the electronic medical record of adults who underwent diagnostic computed tomography (CT) or magnetic resonance imaging (MRI) over a 1-year period for any cause unrelated to known or suspected pituitary disorder both in inpatient and outpatient settings. Patients with International Classification of Diseases, Ninth Revision, (ICD-9) and Tenth Revision (ICD-10) codes indicative of a sellar lesion and those with symptoms suggestive of sellar/parasellar mass effects were excluded. RESULTS: Of 9572 scans performed during the 1-year study period, 3840 met the inclusion criteria to comprise the study cohort; 13 were manually excluded because of findings or symptoms of sellar masses not otherwise captured. The overwhelming majority of evaluable images (n = 3782) showed no sellar lesions. Truly incidental sellar findings were detected in 45 (1.2%), most commonly among inpatients (P < .001). Partially empty sella and empty sella were the most frequent findings, and were twice as likely to be detected on MRI vs CT. All other incidentally discovered lesions, including one microadenoma and one macroadenoma, were detected only by MRI. CONCLUSION: Frequency of incidental sellar lesions in patients with no known or suspected history of pituitary disorder is low. Given the small likelihood of aggressive behavior in these lesions, the clinical significance of truly incidentally discovered sellar lesions should not be overestimated.

Spontaneous intracranial hypotension secondary to congenital spinal dural ectasia and genetic mosaicism for tetrasomy 10p: illustrative case.

BACKGROUND: Spontaneous intracranial hypotension has historically been a poorly understood pathology that is often unrecognized and undertreated. Even more rarely has it been described in pediatric patients with an otherwise benign past medical history. OBSERVATIONS: Herein the authors describe one of the youngest patients ever reported, a 2-year-old girl who developed severe headaches, nausea, and vomiting and experienced headache relief after lying down. Imaging revealed tonsillar herniation 14 mm below the foramen magnum, presumed to be a Chiari malformation, along with extensive dural cysts starting from thoracic level T2 down to the sacrum. She was found to have streaky skin pigmentary variation starting from the trunk down to her feet. Genetic analysis of skin biopsies revealed mosaicism for an isodicentric marker chromosome (10p15.3-10q11.2 tetrasomy) in 27%-50% of cells. After undergoing a suboccipital and cervical decompression at an outside institution, she continued to be symptomatic. She was referred to the authors' hospital, where she was diagnosed with spontaneous intracranial hypotension. LESSONS: After receiving a series of epidural blood patches, the patient experienced almost complete relief of her symptoms. To the authors' knowledge, this is the first time this chromosomal anomaly has ever been reported in a living child, and this may represent a new genetic association with dural ectasia.

Magnetic Resonance Vessel Wall Imaging in Central Nervous System Vasculitides: A Case Series.

INTRODUCTION: We aim to report 3 cases of central nervous system (CNS) vasculitides, in which high-resolution magnetic resonance vessel wall imaging (HR-VWI) findings were instrumental in the diagnosis and management. CASE REPORT: Case 1: A 41-year-old obese, smoker female with arterial hypertension presented with recurrent transient ischemic attacks. Computed topography angiography demonstrated bilateral middle cerebral artery (MCA) stenosis. HR-VWI revealed uniform enhancement and thickening of the arterial wall, suggestive of MCA vasculitis. The patient reported chronic calf rash that was biopsied and revealed unspecified connective tissue disease. With immunomodulation, patient remained asymptomatic and 6-month surveillance HR-VWI showed improved MCA stenoses.Case 2: A 56-year-old male with herpes simplex virus 1 encephalitis was treated with antiviral therapy and improved clinically. Two months later, the brain magnetic resonance imaging revealed new temporo-parietal edema and distal MCA hyperintense vessels. HR-VWI showed MCA concentric smooth contrast enhancement, that was attributed to postinfectious vasculitis and had resolved on follow-up HR-VWI.Case 3: A 41-year-old male presented with 1-week of headache and encephalopathy. Brain magnetic resonance imaging revealed punctate multifocal acute ischemic infarcts and no contrast-enhancement. HR-VWI showed multifocal diffuse enhancement of distal cerebral vasculature. Patient subsequently developed branch retinal artery occlusion and hearing loss and was diagnosed with Susac syndrome. No recurrent symptoms were noted after immunotherapy initiation. CONCLUSIONS: In these 3 cases, HR-VWI identified distinctive vascular inflammatory changes, which were crucial to guide the etiological workup, positive diagnosis, surveillance neuroimaging, and targeted treatment. HR-VWI is an important diagnostic tool in CNS vasculitides, by providing nuanced information about arterial wall integrity and pathology.

Spontaneous retroclival hematoma in pituitary apoplexy: case series.

OBJECT: Pituitary apoplexy is a rare and potentially life-threatening disorder that is most commonly characterized by a combination of sudden headache, visual disturbance, and hypothalamic/hormonal dysfunction. In many cases, there is hemorrhagic infarction of an underlying pituitary adenoma. The resulting clinical symptoms are due to compression of the remaining pituitary, cavernous sinuses, or cranial nerves. However, there are only 2 case reports in the literature describing spontaneous retroclival expansion of hemorrhage secondary to pituitary apoplexy. Ten cases of this entity with a review of the literature are presented here. METHODS: This is a single-institution retrospective review of 2598 patients with sellar and parasellar masses during the 10-year period between 1999 and 2009. The pituitary and brain MRI and MRI studies were reviewed by 2 neuroradiologists for evidence of apoplexy, with particular attention given to retroclival extension. RESULTS: Eighteen patients (13 men and 5 women; mean age 54 years) were identified with presenting symptoms of sudden onset of headache and ophthalmoplegia, and laboratory findings consistent with pituitary apoplexy. Ten of these patients (8 men and 2 women; mean age 55 years) had imaging findings consistent with retroclival hematoma. CONCLUSIONS: Retroclival hemorrhage was seen in the majority of cases of pituitary apoplexy (56%), suggesting that it is more common than previously thought.

Differentiation of benign angiomatous and microcystic meningiomas with extensive peritumoral edema from high grade meningiomas with aid of diffusion weighted MRI.

OBJECTIVE: To determine whether angiomatous and microcystic meningiomas which mimic high grade meningiomas based on extent of peritumoral edema can be reliably differentiated as low grade tumors using normalized apparent diffusion coefficient (ADC) values. METHODS: Preoperative magnetic resonance imaging (MRI) of seventy patients with meningiomas was reviewed. Morphologically, the tumors were divided into 3 groups. Group 1 contained 12 pure microcystic, 3 pure angiomatoid and 7 mixed angiomatoid and microcystic tumors. Group 2 included World Health Organization (WHO) grade II and WHO grade III tumors, of which 28 were atypical and 9 were anaplastic meningiomas. Group 3 included WHO grade I tumors of morphology different than angiomatoid and microcystic. Peritumoral edema, normalized ADC, and cerebral blood volume (CBV) were obtained for all meningiomas. RESULTS: Edema index of tumors in group 1 and group 2 was significantly higher than in group 3. Normalized ADC value in group 1 was higher than in group 2, but not statistically significant between groups 1 and 3. CBV values showed no significant group differences. CONCLUSION: A combination of peritumoral edema index and normalized ADC value is a novel approach to preoperative differentiation between true aggressive meningiomas and mimickers such as angiomatous and microcystic meningiomas.

Anti-NMDA encephalitis: an uncommon, autoimmune mediated form of encephalitis.

We report an interesting case of a 19 year old female with findings on MRI suggestive of viral encephalitis. An extensive workup was negative for infectious causes and she was subsequently diagnosed with anti-NMDA encephalitis. Anti-NMDA encephalitis is a highly lethal but treatable form of autoimmune encephalitis that has recently been characterized. It is frequently found in young women and associated with an underlying teratoma. Although rare, this diagnosis should be considered in young females for whom a rapid onset of encephalitis cannot be explained by more common causes.

Pituitary magnetic resonance imaging for sellar and parasellar masses: ten-year experience in 2598 patients.

CONTEXT: Sellar and parasellar masses present with overlapping clinical and radiological features ranging from asymptomatic incidental presentations and hormonal effects to compressive local mass effects. Pituitary masses are diagnosed with increased frequency with magnetic resonance imaging (MRI) advancements and availability, but indications and diagnostic outcomes of MRI screening for sellar lesions are not defined. Although pituitary adenomas are the most frequently encountered sellar mass lesions, other etiologies should be considered in the differential diagnosis of a sellar mass. SETTING: The study was conducted at a tertiary pituitary center. PATIENTS: This study was a retrospective review of 2598 subjects undergoing at least one pituitary MRI scan from 1999 to 2009. MAIN OUTCOME MEASURE: Prevalence and diagnosis of specific sellar and parasellar masses as screened by pituitary MRI. RESULTS: The most common indications for pituitary imaging, excluding known mass follow-up, were for evaluation of hyperprolactinemia or hypogonadism. A normal pituitary gland was reported in 47% of subjects undergoing pituitary MRI. The most common pituitary adenomas initially identified by MRI included prolactinoma (40%), nonfunctioning adenoma (37%), and GH adenoma (13%). Nonadenomatous sellar masses accounted for 18% of visible lesions, of which the most common were Rathke's cleft cyst (19%), craniopharyngioma (15%), and meningioma (15%). Metastases accounted for 5% of nonpituitary lesions and breast cancer was the most common primary source. CONCLUSIONS: Half of all pituitary MRI scans performed in a large patient population yielded no visible lesion. Nonadenomatous pituitary lesions should be considered in the diagnosis of sellar masses observed on MRI, and a high clinical suspicion is required to exclude the presence of a nonfunctioning pituitary adenoma.