Applying the 2022 optic neuritis criteria to noninflammatory optic neuropathies with optic nerve T2-hyperintensity: an observational study

INTRODUCTION

Recent diagnostic criteria for optic neuritis include T2-hyperintensity of the optic nerve (ON), even without associated contrast enhancement. However, isolated ON-T2-hyperintensity is a nonspecific finding found in any optic neuropathy or severe retinopathy. We applied the 2022 optic neuritis diagnostic criteria to a cohort of patients with noninflammatory optic neuropathy and ON-T2-hyperintensity in at least one eye, to assess the rate of optic neuritis misdiagnosis using these criteria.

METHODS

Retrospective study of consecutive patients who underwent brain/orbit MRI with/without contrast between 07/01/2019 and 06/30/2022. Patients with ON-T2-hyperintensity in at least one eye were included. The 2022 optic neuritis diagnostic criteria were applied to patients with noninflammatory optic neuropathies who had an ophthalmologic examination available for review.

RESULTS

Of 150 patients included, 85/150 had compressive optic neuropathy; 32/150 had glaucoma; 12/150 had papilledema; 8/150 had hereditary (3), radiation-induced (3), nutritional (1), traumatic (1) optic neuropathies (none fulfilled the criteria); 13/150 had ischemic optic neuropathy and 4 fulfilled the criteria as definite optic neuritis due to contrast enhancement of the ON head. Seven additional patients would have satisfied the diagnostic criteria if red flags for alternative diagnoses had been overlooked.

DISCUSSION

The application of the 2022 optic neuritis diagnostic criteria in patients with noninflammatory optic neuropathy and ON-T2-hyperintensity in at least one ON resulted in misdiagnosis of optic neuritis in only 4 patients because of ON head enhancement, all with nonarteritic anterior ischemic optic neuropathy. Neuro-ophthalmologic evaluation and exclusion of the ON head as a location in the MRI criteria would have prevented optic neuritis misdiagnosis in our study.

Optic Nerve MRI T2-Hyperintensity: A Nonspecific Marker of Optic Nerve Damage

BACKGROUND

MRI abnormalities are common in optic neuropathies, especially on dedicated orbital imaging. In acute optic neuritis, optic nerve T2-hyperintensity associated with optic nerve contrast enhancement is the typical imaging finding. In chronic optic neuropathies, optic nerve T2-hyperintensity and atrophy are regularly seen. Isolated optic nerve T2-hyperintensity is often erroneously presumed to reflect optic neuritis, frequently prompting unnecessary investigations and neuro-ophthalmology consultations. Our goal was to determine the significance of optic nerve/chiasm T2-hyperintensity and/or atrophy on MRI.

METHODS

Retrospective study of consecutive patients who underwent brain/orbital MRI with/without contrast at our institution between July 1, 2019, and June 6, 2022. Patients with optic nerve/chiasm T2-hyperintensity and/or atrophy were included. Medical records were reviewed to determine the etiology of the T2-hyperintensity and/or atrophy.

RESULTS

Four hundred seventy-seven patients (698 eyes) were included [mean age 52 years (SD ±18 years); 57% women]. Of the 364 of 698 eyes with optic nerve/chiasm T2-hyperintensity without atrophy, the causes were compressive (104), inflammatory (103), multifactorial (49), glaucoma (21), normal (19), and other (68); of the 219 of 698 eyes with optic nerve/chiasm T2-hyperintensity and atrophy, the causes were compressive (57), multifactorial (40), inflammatory (38), glaucoma (33), normal (7), and other (44); of the 115 of 698 eyes with optic nerve/chiasm atrophy without T2-hyperintensity, the causes were glaucoma (34), multifactorial (21), inflammatory (13), compressive (11), normal (10), and other (26). Thirty-six eyes with optic nerve/chiasm T2-hyperintensity or atrophy did not have evidence of optic neuropathy or retinopathy on ophthalmologic examination, and 17 eyes had clinical evidence of severe retinopathy without primary optic neuropathy.

CONCLUSIONS

Optic nerve T2-hyperintensity or atrophy can be found with any cause of optic neuropathy and with severe chronic retinopathy. These MRI findings should not automatically prompt optic neuritis diagnosis, workup, and treatment, and caution is advised regarding their use in the diagnostic criteria for multiple sclerosis. Cases of incidentally found MRI optic nerve T2-hyperintensity and/or atrophy without a known underlying optic neuropathy or severe retinopathy are rare. Such patients should receive an ophthalmologic examination before further investigations.

Glaucoma as a cause of optic nerve abnormalities on magnetic resonance imaging

BACKGROUND/OBJECTIVES

To report a series of patients with glaucoma and optic nerve abnormalities on magnetic resonance imaging (MRI) in at least one-eye, and to determine whether these findings correlate with the severity of glaucoma.

PATIENTS AND METHODS

Retrospective study of all patients who underwent a brain/orbits MRI without and with contrast at our institution between 07/1/2019-6/30/2022. Patients with optic nerve T2-hyperintensity and/or MRI optic nerve atrophy in at least one-eye and a diagnosis of isolated glaucoma in at least one-eye were included. Demographic information, glaucoma clinical characteristics, glaucoma severity parameters, and MRI indication were collected.

RESULTS

Fifty-six patients (112 eyes) (age 65 years-old [range 26-88]; 70% male) had isolated bilateral glaucoma with at least one-eye MRI optic nerve abnormality. The indication for MRI was atypical/asymmetric glaucoma in 91% of patients. Of the 112 eyes, 23 had optic nerve T2-hyperintensity alone; 33 had both optic nerve T2-hyperintensity and MRI optic nerve atrophy; 34 had MRI optic nerve atrophy alone; and 22 did not have abnormal optic nerve MRI-findings. None had optic nerve enhancement. A statistically significant association between optic nerve T2-hyperintensity or MRI optic nerve atrophy and glaucoma severity parameters was found.

CONCLUSIONS

Glaucoma is a clinical diagnosis and MRI brain is usually not required, except in atypical or asymmetric cases. Optic nerve T2-hyperintensity and MRI optic nerve atrophy are nonspecific MRI-findings that can be found in severe glaucomatous optic nerves and should not systematically prompt investigations for another cause of optic neuropathy.

Seizures as the Initial Manifestation of Idiopathic Intracranial Hypertension Spectrum Disorder

Idiopathic intracranial hypertension (IIH) is a syndrome of isolated elevated intracranial pressure of unknown aetiology. The IIH spectrum has evolved over the past decade making the diagnosis and management more challenging. The neurological examination in IIH is typically normal except for papilloedema and possible cranial nerve 6 palsy. Recent publications have highlighted skull base thinning and remodelling in patients with chronic IIH. Resulting skull base defects can cause meningo-encephalocoeles, which are potential epileptogenic foci. We describe the clinical and radiological characteristics of five IIH patients with seizures and meningo-encephalocoeles as the presenting manifestations of IIH spectrum disorder.

Automated Registration and Color Labeling of Serial 3D Double Inversion Recovery MR Imaging for Detection of Lesion Progression in Multiple Sclerosis

Automated co-registration and subtraction techniques have been shown to be useful in the assessment of longitudinal changes in multiple sclerosis (MS) lesion burden, but the majority depend on T2-fluid-attenuated inversion recovery sequences. We aimed to investigate the use of a novel automated temporal color complement imaging (CCI) map overlapped on 3D double inversion recovery (DIR), and to assess its diagnostic performance for detecting disease progression in patients with multiple sclerosis (MS) as compared to standard review of serial 3D DIR images. We developed a fully automated system that co-registers and compares baseline to follow-up 3D DIR images and outputs a pseudo-color RGB map in which red pixels indicate increased intensity values in the follow-up image (i.e., progression; new/enlarging lesion), blue-green pixels represent decreased intensity values (i.e., disappearing/shrinking lesion), and gray-scale pixels reflect unchanged intensity values. Three neuroradiologists blinded to clinical information independently reviewed each patient using standard DIR images alone and using CCI maps based on DIR images at two separate exams. Seventy-six follow-up examinations from 60 consecutive MS patients who underwent standard 3 T MR brain MS protocol that included 3D DIR were included. Median cohort age was 38.5 years, with 46 women, 59 relapsing-remitting type MS, and median follow-up interval of 250 days (interquartile range: 196-394 days). Lesion progression was detected in 67.1% of cases using CCI review versus 22.4% using standard review, with a total of 182 new or enlarged lesions using CCI review versus 28 using standard review. There was a statistically significant difference between the two methods in the rate of all progressive lesions (P < 0.001, McNemar's test) as well as cortical progressive lesions (P < 0.001). Automated CCI maps using co-registered serial 3D DIR, compared to standard review of 3D DIR alone, increased detection rate of MS lesion progression in patients undergoing clinical brain MRI exam.

Association Between Hippocampal Volume and African Neuropsychology Memory Tests in Adult Individuals with Probable Alzheimer's Disease in Democratic Republic of Congo

BACKGROUND

Western studies indicate potential associations between hippocampal volume and memory in the trajectory of Alzheimer's disease (AD). However, limited availability of neuroimaging technology and neuropsychological tests appropriate for sub-Saharan African (SSA) countries makes it difficult to establish neuroanatomical associations of hippocampus and memory in this locale.

OBJECTIVE

This study examined hippocampal volumes and memory in healthy control (HC) and probable AD groups in the Democratic Republic of Congo (DRC).

METHODS

Forty-six subjects with probable AD and 29 HC subjects were screened using the Community Instrument for Dementia and the Alzheimer Questionnaire. Participants underwent neuroimaging in Kinshasa, DRC, and memory was evaluated using the African Neuropsychology Battery (ANB). Multiple linear regression was used to determine associations between hippocampal volumes and memory.

RESULTS

Patients with probable AD performed significantly worse than HCs on ANB memory measures, and exhibited greater cerebral atrophy, which was significantly pronounced in the medial temporal lobe region (hippocampus, entorhinal cortex). Both AD and HC subjects exhibited high rates of white matter hyperintensities compared to international base rate prevalence, which was significantly worse for probable AD. Both also exhibited elevated rates of microhemorrhages. Regression analysis demonstrated a significant association between hippocampal volume and ANB memory tests. Hippocampal atrophy discriminated probable AD from the HC group.

CONCLUSIONS

This study establishes the feasibility of conducting neuroimaging research in the SSA, demonstrates many known neuroimaging findings in probable AD patients hold up using culturally appropriate memory tasks, and suggest cardiovascular problems are a greater issue in SSA than in Western countries.

Intracranial computed tomography histogram analysis detects changes in the setting of elevated intracranial pressure and normal imaging

BACKGROUND

Patients with idiopathic intracranial hypertension (IIH) have elevated intracranial pressure (ICP) of unclear etiology. This study evaluated the ability of quantitative intracranial Hounsfield unit (HU) histogram analysis to detect pathophysiological changes from elevated ICP in the setting of a normal head CT.

METHODS

Retrospective analysis of non-contrast-enhanced head CT images of IIH patients and matched controls. Following skull stripping, total intracranial CT voxels within the range of 0-70 HU were divided into seven 10 HU bins. A measurement of total intracranial HU was also calculated for each patient. Imaging studies for IIH patients were reviewed for features of IIH including transverse sinus stenosis (TSS). Histogram measures were compared between IIH and control groups and correlated with imaging and clinical data.

RESULTS

Fourteen IIH patients with CSF opening pressure ≥25 cm water, and 31 age-, sex-, and ethnicity-matched controls were included. Compared to controls, IIH patients had a significantly greater proportion of voxels in the 40-50, 50-60, and 60-70 HU bins (p = 0.003, 0.001, and 0.003, respectively) but similar proportion in the 0-10 HU range. Severity of TSS significantly correlated with total intracranial HU measures. 50-60 HU and 60-70 HU bins demonstrated high AUCs of 0.81 and 0.80, respectively, in differentiating IIH from normal status.

CONCLUSION

Idiopathic intracranial hypertension patients have a greater proportion of high intracranial HU voxels representing blood volume, which may be explained by TSS causing venous congestion. The pattern provides further insights into the pathophysiology of IIH and may be useful for detecting elevated ICP in the setting of normal head CT imaging.

Carotid-Cavernous Fistula Presenting as Isolated Painful Anisocoria

A painful isolated third nerve palsy is an uncommon presenting sign of a carotid-cavernous fistula (CCF). It mostly occurs in dural CCFs with posterior drainage into the petrosal sinuses. We present a case of a 50-year-old woman who developed acute right periorbital facial pain in the territory of the first branch of the right trigeminal nerve and was noted to have a right dilated unreactive pupil with very subtle right ptosis. She was subsequently diagnosed with a posteriorly draining dural CCF.

Retinal and optic nerve magnetic resonance diffusion-weighted imaging in acute non-arteritic central retinal artery occlusion

OBJECTIVES

Diffusion weighted imaging hyperintensity (DWI-H) has been described in the retina and optic nerve during acute central retinal artery occlusion (CRAO). We aimed to determine whether DWI-H can be accurately identified on standard brain magnetic resonance imaging (MRI) in non-arteritic CRAO patients at two tertiary academic centers.

MATERIALS AND METHODS

Retrospective cross-sectional study that included all consecutive adult patients with confirmed acute non-arteritic CRAO and brain MRI performed within 14 days of CRAO. At each center, two neuroradiologists masked to patient clinical data reviewed each MRI for DWI-H in the retina and optic nerve, first independently then together. Statistical analysis for inter-rater reliability and correlation with clinical data was performed.

RESULTS

We included 204 patients [mean age 67.9±14.6 years; 47.5% females; median time from CRAO to MRI 1 day (IQR 1-4.3); 1.5 T in 127/204 (62.3%) and 3.0 T in 77/204 (37.7%)]. Inter-rater reliability varied between centers (κ = 0.27 vs. κ = 0.65) and was better for retinal DWI-H. Miss and error rates significantly differed between neuroradiologists at each center. After consensus review, DWI-H was identified in 87/204 (42.6%) patients [miss rate 117/204 (57.4%) and error rate 11/87 (12.6%)]. Significantly more patients without DWI-H had good visual acuity at follow-up (p = 0.038).

CONCLUSIONS

In this real-world case series, differences in agreement and interpretation accuracy among neuroradiologists limited the role of DWI-H in diagnosing acute CRAO on standard MRI. DWI-H was identified in 42.6% of patients and was more accurately detected in the retina than in the optic nerve. Further studies are needed with standardized novel MRI protocols.

Superior Verbal Memory Outcome After Stereotactic Laser Amygdalohippocampotomy

Objective: To evaluate declarative memory outcomes in medically refractory epilepsy patients who underwent either a highly selective laser ablation of the amygdalohippocampal complex or a conventional open temporal lobe resection. Methods: Post-operative change scores were examined for verbal memory outcome in epilepsy patients who underwent stereotactic laser amygdalohippocampotomy (SLAH: n = 40) or open resection procedures (n = 40) using both reliable change index (RCI) scores and a 1-SD change metric. Results: Using RCI scores, patients undergoing open resection (12/40, 30.0%) were more likely to decline on verbal memory than those undergoing SLAH (2/40 [5.0%], p = 0.0064, Fisher's exact test). Patients with language dominant procedures were much more likely to experience a significant verbal memory decline following open resection (9/19 [47.4%]) compared to laser ablation (2/19 [10.5%], p = 0.0293, Fisher's exact test). 1 SD verbal memory decline frequently occurred in the open resection sample of language dominant temporal lobe patients with mesial temporal sclerosis (8/10 [80.0%]), although it rarely occurred in such patients after SLAH (2/14, 14.3%) (p = 0.0027, Fisher's exact test). Memory improvement occurred significantly more frequently following SLAH than after open resection. Interpretation: These findings suggest that while verbal memory function can decline after laser ablation of the amygdalohippocampal complex, it is better preserved when compared to open temporal lobe resection. Our findings also highlight that the dominant hippocampus is not uniquely responsible for verbal memory. While this is at odds with our simple and common heuristic of the hippocampus in memory, it supports the findings of non-human primate studies showing that memory depends on broader medial and lateral TL regions.

Prediction of Postoperative Risk of Raised Intracranial Pressure After Spontaneous Skull Base Cerebrospinal Fluid Leak Repair

BACKGROUND

A relationship between idiopathic intracranial hypertension and spontaneous skull base cerebrospinal fluid (CSF) leaks has been proposed, by which CSF leak decreases intracranial pressure (ICP) and masks the symptoms and signs of elevated ICP. These patients are at risk of developing papilledema, symptoms of elevated ICP, or a recurrent CSF leak after CSF leak repair. The objective of this study was to assess whether radiographic signs of raised ICP on preoperative magnetic resonance or computed venography (MRI or CTV) are predictors of postoperative papilledema, recurrence of CSF leak, or need for CSF shunt surgery.

METHODS

We performed a retrospective review of systematically collected demographics, fundus examination, and presurgical brain MRI and magnetic resonance venography/computed tomography venography (MRV/CTV) in patients seen at 1 institution between 2013 and 2019 with spontaneous skull base CSF leak repair. Patients were divided into 2 groups depending on whether they developed papilledema, recurrent CSF leak, or required CSF shunting (Group 1) or not (Group 2).

RESULTS

Fifty-seven patients were included, among whom 19 were in Group 1. There was no difference in demographic characteristics or clinical features between patients in Group 1 and Group 2. Controlling for other imaging features, bilateral transverse venous sinus stenosis (TVSS) on preoperative imaging increased the odds of being in Group 1 by 4.2 times (95% confidence interval [CI], 1.04-21.2, P = 0.04), optic nerve tortuosity decreased the odds of being in Group 1 by 8.3 times (95% CI: 1.4-74.6, P = 0.02).

CONCLUSION

Imaging of the intracranial venous system with MRV or CTV is warranted before repair of spontaneous CSF leak, as bilateral TVSS is an independent risk factor for postoperative papilledema, CSF leak recurrence, or need for a CSF shunting procedure.

Spinal Arachnoid Webs: Presentation, Natural History, and Outcomes in 38 Patients

BACKGROUND

Spinal arachnoid webs are rarely described bands of thickened arachnoid tissue in the dorsal thoracic spine. Much is unknown regarding their origins, risk factors, natural history, and outcomes.

OBJECTIVE

To present the single largest case series, detailing presenting symptoms and outcomes amongst operative and nonoperative patients, to better understand the role of intervention.

METHODS

This retrospective chart review identified 38 patients with arachnoid webs. Patient demographics, radiologic signs, symptoms, and surgical history data were extracted from the electronic medical record. Symptoms were divided by location and character. 28 patients were successfully contacted for follow up outcome surveys.

RESULTS

26 patients (68%) underwent surgical intervention, 12 (32%) were managed non-operatively. 15 (39%) patients had undergone a previous unsuccessful surgery at a different site for their symptoms prior to arachnoid web diagnosis. Commonly presenting symptoms included myelopathy (68%), focal thoracic back pain (68%), lower extremity weakness (45%), numbness and sensory changes (58%), and lower extremity radicular pain (42%), upper extremity weakness (24%), and radicular pain (37%). Focal thoracic pain was associated with thoracic level (P < .02). Myelopathic symptoms were less common in postoperative patients. Postoperative patients described significantly more upper extremity (P < .01) and thoracic (P < .01) numbness and paresthesias. Surveyed nonoperative patients universally described their symptoms as either stable or worsening.

CONCLUSION

Spinal arachnoid webs present with thoracic myelopathy and back pain but can also present with upper extremity symptoms. Surgical intervention stabilizes or improves symptoms and is well received. Nonoperative patients do not spontaneously improve.

Secondary Interpretations of Diagnostic Imaging Examinations: Patient Liabilities and Out-of-Pocket Costs

BACKGROUND

Secondary interpretations of diagnostic imaging examinations are increasingly performed to improve care for complex patients. We sought to determine associated patient-billed liabilities and out-of-pocket payments and to identify patient and imaging study characteristics that correlate with higher patient bills and out-of-pocket payments.

METHODS

Data extracted for 7,740 secondary imaging interpretations performed across our large metropolitan health system over 25 months included total professional charges, insurance payments, patient-billed liabilities, and patient out-of-pocket payments. Multivariable linear regression analyses were performed to identify patient and imaging factors associated with higher patient bills and out-of-pocket payments.

RESULTS

Mean secondary interpretation professional charges, insurance payments, patient-billed liabilities, and patient out-of-pocket payments were $306.50, $108.02, $27.80, and $14.55, respectively. Patients received bills for 47.5% of services and made out-of-pocket payments for 17.1%. Patient-billed liabilities and out-of-pocket payments were higher for patients who were younger and uninsured and for secondary interpretations requested for patients seen in outpatient (versus inpatient) settings. Patient-billed liabilities and out-of-pocket payments were lower for patients who were Black (versus White) and had government-sponsored (versus commercial) insurance and for secondary interpretations performed during the second, third, or fourth (versus first) quarter of each calendar year.

CONCLUSION

Observed differences between patient-billed liabilities and out-of-pocket payments suggest that secondary interpretations of diagnostic imaging examinations can result in small but real patient financial burdens. Improved price transparency and enhanced patient communication about the value of secondary interpretations could reduce potential surprises when patients receive these bills.

Prevalence of Incidentally Detected Signs of Intracranial Hypertension on Magnetic Resonance Imaging and Their Association With Papilledema

Importance

Magnetic resonance imaging (MRI) signs of intracranial hypertension (IH) are traditionally associated with idiopathic intracranial hypertension (IIH), but these signs are also detected among individuals with primary headaches and among asymptomatic individuals without papilledema.

Objective

To examine the prevalence of MRI signs of IH among consecutive outpatients undergoing brain MRI for any clinical indication and to explore their association with papilledema.

Design, Setting, and Participants

This prospective cross-sectional study of outpatients undergoing brain MRI at 1 outpatient imaging facility was conducted between August 1, 2019, and March 31, 2020, with ocular fundus photographs taken concurrently. Radiographic images from consecutive adult patients who were undergoing brain MRI and able to participate in fundus photography were analyzed for MRI signs of IH. A univariate analysis using either Fisher exact tests or t tests was performed.

Main Outcomes and Measures

Prevalence of MRI signs of IH and prevalence of papilledema detected on ocular fundus photographs. Radiographic signs of IH included empty sella, optic nerve head protrusion, posterior scleral flattening, increased perioptic cerebrospinal fluid, optic nerve tortuosity, enlarged Meckel caves, cephaloceles, cerebellar tonsillar descent, and bilateral transverse venous sinus stenosis.

Results

A total of 388 patients were screened for eligibility; of those, 92 patients were excluded (58 declined participation, 16 were unable to consent, 14 were unable to complete fundus photography, and 4 completed MRI and fundus photography twice, so their second set of findings was removed). Among the 296 patients included in the study, the median age was 49.5 years (interquartile range, 37.8-62.0 years), and 188 patients (63.5%) were female. The most common indication for MRI was surveillance of a brain neoplasm (82 patients [27.7%]). Investigations of headaches (26 patients [8.8%]) and disorders of intracranial pressure (4 patients [1.4%]) were uncommon. At least 1 radiographic sign of IH was present in 145 patients (49.0%). Among 296 total study patients, 98 patients (33.1%) had empty sella, 47 patients (15.9%) had enlarged Meckel caves, 32 patients (10.8%) had increased perioptic cerebrospinal fluid, 23 patients (7.8%) had optic nerve tortuosity, 2 patients (0.7%) had scleral flattening, and 4 patients (1.4%) had cephaloceles. Bilateral transverse venous sinus stenosis was present in 6 of 198 patients (3.0%). Five patients (1.7%) had papilledema. Compared with patients without papilledema, those with papilledema had a significantly higher body mass index and history of IIH, in addition to an increased prevalence of empty sella, optic nerve tortuosity, and transverse venous sinus stenosis detected on MRI. The prevalence of papilledema increased from 2.8% among patients with at least 1 MRI sign of IH to 40.0% among patients with 4 or more MRI signs of IH.

Conclusions and Relevance

Magnetic resonance imaging signs of IH were common among patients undergoing brain MRI in this study but rarely associated with papilledema. The management of patients with incidentally detected signs of IH likely does not require systematic lumbar puncture unless concerning symptoms or papilledema are present.

MRI-guided stereotactic laser corpus callosotomy for epilepsy: distinct methods and outcomes

OBJECTIVE

Several small series have described stereotactic MRI-guided laser interstitial thermal therapy for partial callosotomy of astatic and generalized tonic-clonic (GTC) seizures, especially in association with Lennox-Gastaut syndrome. Larger case series and comparison of distinct stereotactic methods for stereotactic laser corpus callosotomy (SLCC), however, are currently lacking. The objective of this study was to report seizure outcomes in a series of adult patients with epilepsy following anterior, posterior, and complete SLCC procedures and to compare the results achieved with a frameless stereotactic surgical robot versus direct MRI guidance frames.

METHODS

The authors retrospectively reviewed sequential adult epilepsy surgery patients who underwent SLCC procedures at a single institution. They describe workflows, stereotactic errors, percentage disconnection, hospitalization durations, adverse events, and seizure outcomes after performing anterior, posterior, and complete SLCC procedures using a frameless stereotactic surgical robot versus direct MRI guidance platforms.

RESULTS

Thirteen patients underwent 15 SLCC procedures. The median age at surgery was 29 years (range 20-49 years), the median duration of epilepsy was 21 years (range 9-48 years), and median postablation follow-up was 20 months (range 4-44 months). Ten patients underwent anterior SLCC with a median 73% (range 33%-80%) midsagittal length of callosum acutely ablated. Following anterior SLCC, 6 of 10 patients achieved meaningful (> 50%) reduction of target seizures. Four patients underwent posterior (completion) SLCC following prior anterior callosotomy, and 1 patient underwent complete SLCC as a single procedure; 3 of these 5 patients experienced meaningful reduction of target seizures. Overall, 8 of 10 patients in whom astatic seizures were targeted and treated by anterior and/or posterior SLCC experienced meaningful improvement. SLCC procedures with direct MRI guidance (n = 7) versus a frameless surgical robot (n = 8) yielded median radial accuracies of 1.1 mm (range 0.2-2.0 mm) versus 2.4 mm (range 0.6-6.1 mm; p = 0.0011). The most serious adverse event was a clinically significant intraparenchymal hemorrhage in a patient who underwent the robotic technique.

CONCLUSIONS

This is the largest reported series of SLCC for epilepsy to date. SLCC provides seizure outcomes comparable to open surgery outcomes reported in the literature. Direct MRI guidance is more accurate, which has the potential to reduce the risks of SLCC. Methodological advancements and larger studies are needed.

Detection of Cortical and Deep Gray Matter Lesions in Multiple Sclerosis Using DIR and FLAIR at 3T

BACKGROUND AND PURPOSE

The comparative detection rates of deep gray matter (GM) multiple sclerosis (MS) lesions using double inversion recovery (DIR) and fluid-attenuated inversion-recovery (FLAIR) on 3T MR imaging remain unknown. We aimed to assess the detectability of cortical and deep GM MS lesions using DIR and FLAIR on 3T clinical exams and evaluate the relationship between deep GM lesions and brain atrophy.

METHODS

One hundred fifty consecutive MS patients underwent routine brain MRI that included 3D DIR and 2D T2 FLAIR on the same 3T scanner. Three neuroradiologists independently reviewed all exams for cortical and deep GM lesions. Statistical parametric mapping (SPM) and FMRIB software library (FSL)-FIRST pipelines were used to determine normalized whole brain and deep GM volumes.

RESULTS

A total of 65 cortical and 98 deep lesions were detected on DIR versus 24 and 20, respectively, on FLAIR. Among all 150 patients, the number and percentage of patients with GM lesions on DIR and FLAIR were as follows: cortical 43 (28.7%) versus 24 (16.0%) (P < .001), thalamus 47 (31.3%) versus 20 (13.3%) (P < .001), putamen 10 (6.7%) versus 3 (2.0%) (P = .02), globus pallidus 9 (6.0%) versus 3 (1.3%) (P = .02), and caudate 5 (3.3%) versus 1 (0.7%) (P = .125). Presence of deep GM lesions weakly correlated with deep GM volume fractions.

CONCLUSION

Deep GM MS lesions can be detected using routine clinical brain MRI including DIR and FLAIR at 3T. Future studies to optimize these sequences may improve the detection rates of cortical and deep GM lesions. The presence of GM lesions showed weak correlation with GM atrophy.

The use of contrast-enhanced, time-resolved magnetic resonance angiography in cerebrovascular pathology

Digital subtraction angiography (DSA) has long been the imaging gold standard in the evaluation, treatment, and follow-up of cerebro- and spinovascular disorders. However, DSA has the disadvantages of invasiveness, contrast allergy or nephropathy, the impracticality of procedural preparation and recovery, and expense. Contrast-enhanced (CE), time-resolved (TR) magnetic resonance angiography (CE TR-MRA) is a sophisticated, relatively novel imaging modality that provides multiphasic contrast-enhanced visualization of the neurovasculature. Given the crucial role of angiography in all aspects of care for patients with complex neurovascular disorders, it is incumbent on those who care for these patients to understand the usefulness and pitfalls of novel imaging in this arena to ensure best practices, and to deliver cutting edge care to these patients in a way that minimizes cost, but does not compromise quality. CE TR-MRA has the potential to play an expanded role in the workup and follow-up across the spectrum of neurovascular disease, and this review is aimed to help neurosurgeons better understand how CE TR-MRA can be used to better manage patients in this cohort.

Appearance of an unusual ring enhancing brain capillary telangiectasia on 3.0T MRI with dynamic susceptibility contrast perfusion

We present the appearance of brain capillary telangiectasia on 3.0T magnetic resonance imaging (MRI) perfusion. A 42-year-old female presented with intermittent left arm weakness and paresthesia. Initial 1.5T MRI obtained 2 months after presentation demonstrated a 6 mm right caudate head lesion with ring-like enhancement, and no significant surrounding edema or mass effect. On gradient echo there was mild associated susceptibility artifact. Follow-up 3.0T MRI demonstrated increased blooming on 3.0T imaging relative to prior 1.5T imaging. The lesion also demonstrated increased blood volume on dynamic susceptibility contrast perfusion. Given these imaging findings and interval stability, a definitive imaging diagnosis of capillary telangiectasia was made. Recognition of the MRI findings of capillary telangiectasia is imperative to avoid misdiagnosis and prevent unnecessary intervention.

Spontaneous Skull Base Cerebrospinal Fluid Leaks and Their Relationship to Idiopathic Intracranial Hypertension

Background

The association between spontaneous skull base cerebrospinal fluid (CSF) leaks and idiopathic intracranial hypertension (IIH) has been suggested, but its significance remains unclear.

Objective

To estimate the prevalence of IIH in spontaneous skull base CSF leak patients.

Methods

Systematic collection of demographics, neuro-ophthalmic and magnetic resonance imaging evaluation of spontaneous skull base CSF leak patients seen pre- and post-leak repair in one neuro-ophthalmology service. Patients with preexisting IIH were diagnosed with definite IIH if adequate documentation was provided; otherwise, they were categorized with presumed IIH. Classic radiographic signs of intracranial hypertension and bilateral transverse venous sinus stenosis were recorded.

Results

Thirty six patients were included (age [interquartile range]: 50 [45;54] years; 94% women; body mass index: 36.8 [30.5;39.9] kg/m2), among whom six (16.7%, [95% confidence interval, CI]: [6.4;32.8]) had a preexisting diagnosis of definite or presumed IIH. Of the remaining 30 patients, four (13.3%, 95%CI: [3.8;30.7]) had optic nerve head changes suggesting previously undiagnosed IIH, while one was newly diagnosed with definite IIH at initial consultation. One out of 29 patients with normal findings of the optic nerve head at presentation developed new onset papilledema following surgery (3.4%, 95%CI: [0.1;17.8]) and was ultimately diagnosed with definite IIH. Overall, the prevalence of definite IIH was 19.4% (95%CI: [8.2;36.0]).

Conclusion

Striking demographic overlap exists between IIH patients and those with spontaneous CSF leak. Definite IIH was present in approximately 20% of our patients. However, its true prevalence is likely higher than identified by using classic criteria. We therefore hypothesize that an active CSF leak serves as an auto-diversion for CSF, thereby “treating” the intracranial hypertension and eliminating characteristic signs and symptoms at initial presentation.

Mechanisms and Risk Factors Contributing to Visual Field Deficits following Stereotactic Laser Amygdalohippocampotomy

Selective laser amygdalohippocampotomy (SLAH) is a minimally invasive surgical treatment for medial temporal lobe epilepsy. Visual field deficits (VFDs) are a significant potential complication. The objective of this study was to determine the relationship between VFDs and potential mechanisms of injury to the optic radiations and lateral geniculate nucleus. We performed a retrospective cross-sectional analysis of 3 patients (5.2%) who developed persistent VFDs after SLAH within our larger series (n = 58), 15 healthy individuals and 10 SLAH patients without visual complications. Diffusion tractography was used to evaluate laser catheter penetration of the optic radiations. Using a complementary approach, we evaluated evidence for focal microstructural tissue damage within the optic radiations and lateral geniculate nucleus. Overablation and potential heat radiation were assessed by quantifying ablation and choroidal fissure CSF volumes as well as energy deposited during SLAH.SLAH treatment parameters did not distinguish VFD patients. Atypically high overlap between the laser catheter and optic radiations was found in 1/3 VFD patients and was accompanied by focal reductions in fractional anisotropy where the catheter entered the lateral occipital white matter. Surprisingly, lateral geniculate tissue diffusivity was abnormal following, but also preceding, SLAH in patients who subsequently developed a VFD (all p = 0.005).In our series, vision-related complications following SLAH, which appear to occur less frequently than following open temporal lobe -surgery, were not directly explained by SLAH treatment parameters. Instead, our data suggest that variations in lateral geniculate structure may influence susceptibility to indirect heat injury from transoccipital SLAH.

Comparison of Unenhanced and Gadolinium-Enhanced Imaging in Multiple Sclerosis: Is Contrast Needed for Routine Follow-Up MRI?

BACKGROUND AND PURPOSE

Gadolinium enhanced MRI is routinely used for follow-up of patients with multiple sclerosis. Our aim was to evaluate whether enhancing multiple sclerosis lesions on follow-up MR imaging can be detected by visual assessment of unenhanced double inversion recovery and FLAIR sequences.

MATERIALS AND METHODS

A total of 252 consecutive MRIs in 172 adult patients with a known diagnosis of multiple sclerosis were reviewed. The co-presence or absence of associated double inversion recovery and FLAIR signal abnormality within contrast-enhancing lesions was recorded by 3 neuroradiologists. In a subset of patients with prior comparisons, the number of progressive lesions on each of the 3 sequences was assessed.

RESULTS

A total of 34 of 252 MRIs (13%) demonstrated 55 enhancing lesions, of which 52 (95%) had corresponding hyperintensity on double inversion recovery and FLAIR. All lesions were concordant between double inversion recovery and FLAIR, and the 3 enhancing lesions not visible on either sequence were small (<2 mm) and cortical/subcortical (n = 2) or periventricular (n = 1). A total of 17 (22%) of the 76 MRIs with a prior comparison had imaging evidence of disease progression: Ten (59%) of these showed new lesions on double inversion recovery or FLAIR only, 6 (35%) showed progression on all sequences, and 1 (6%) was detectable only on postcontrast T1, being located in a region of confluent double inversion recovery and FLAIR abnormality.

CONCLUSIONS

There was a high concordance between enhancing lesions and hyperintensity on either double inversion recovery or FLAIR. Serial follow-up using double inversion recovery or FLAIR alone may capture most imaging progression, but isolated enhancing lesions in confluent areas of white matter abnormality could present a pitfall for this approach.

Structured Curriculum Vitae Scoring as a Standardized Tool for Selecting Interview Candidates for Academic Neuroradiology Faculty Positions

BACKGROUND AND PURPOSE

Interview selection of candidates for academic radiology faculty positions is variable and subject to unconscious biases. The purpose of this study was to retrospectively apply a quantitative curriculum vitae (CV) rubric as a screening tool to identify qualified candidates for further consideration in the hiring process.

MATERIALS AND METHODS

Archived CVs submitted by applicants between 2012 and 2017 for neuroradiology faculty positions at our institution were anonymized. One blinded reviewer scored resumes based on categories that included education, work experience, extracurricular/teaching experience, and research. Logistic regression and receiver operating characteristics analysis were performed. This study was IRB exempted.

RESULTS

Of the total 102 applicants, 17 interviews were conducted and 10 candidates were offered a position. Maximum score of the model was 24 points. Mean score was 14 ± 4 (n = 102, range 5-22). Higher total CV score (P = 0.01), medical school ranking (P = 0.03), and number of published manuscripts (P = 0.03) were significantly associated with interview selection. The area under the curve in the ROC analysis for differentiating interview selection based on total CV scoring was 0.69 (95% confidence interval 0.56-0.82). At a cutoff of 14, the model is 82.4% sensitive, and 54.1% specific.

CONCLUSION

Standardized CV scoring is feasible with a cut-off score of 14 points providing high sensitivity in identifying candidates eligible for interview. This tool can potentially be applied in the future to the hiring process as it is neutral to factors such as gender and race and provides an opportunity to address diversity in academic medicine.

The Intriguing Case of a Double Pituitary Adenoma

BACKGROUND

When distinct pituitary hypersecretory manifestations coexist, the differential diagnosis includes plurihormonal or double pituitary adenomas. We describe a rare case of hypercortisolemia and hyperprolactinemia caused by 2 noncontiguous adenomas that required 2 surgeries.

CASE DESCRIPTION

A 37-year-old woman presented with 6 months of weight gain, amenorrhea, joint pain, leg swelling, and skin changes. She received prednisone for possible systemic lupus erythematosus. Four months later, she presented with headaches and new-onset diabetes with glucose >1000 mg/dL. Work-up revealed a right-sided 1.1-cm pituitary adenoma and prolactin level of 152.9 ng/mL (normal: 3-27 ng/mL). She was advised to stop the prednisone, start bromocriptine, and see a pituitary specialist. Examination revealed centripetal obesity, supraclavicular and dorsocervical fat pads, violaceous wide striae, bilateral leg edema, and galactorrhea. Workup confirmed adrenocorticotrophic hormone-dependent Cushing syndrome, with a central-to-peripheral gradient on inferior petrosal sinus sampling bilaterally. Transsphenoidal adenenomectomy yielded an adenoma diffusely positive for prolactin. Postoperatively prolactin normalized, hypercortisolemia persisted, and magnetic resonance imaging findings raised suspicion for a 2-mm microadenoma. The patient underwent a second operation when an adrenocorticotrophic hormone-positive adenoma was identified. After 4 years, both hypersecretory syndromes remain in biochemical remission.

CONCLUSIONS

A complete clinical and biochemical evaluation is necessary in patients with pituitary adenomas. Repeat surgery may be necessary for noncontiguous double adenomas.

Pre-operative MRI predictors of hormonal remission status post pituitary adenoma resection

INTRODUCTION

Contrast-enhanced (CE) Constructive Interference in Steady State (CISS) and Volumetric Interpolated Breath-hold Examination (VIBE) are MRI sequences used to improve the detection of pituitary adenomas and adjacent cranial nerves. The purpose of this study was to assess image quality and identify imaging predictors of postoperative hormonal remission of functioning pituitary adenomas using CE-T1 weighted image (WI), T2WI, CE-CISS, and CE-VIBE MRI sequences.

MATERIALS AND METHODS

Patients with pre-operative CE-T1WI, T2WI, CE-CISS, and CE-VIBE pituitary MRI sequences were included in this institutional retrospective review. Three raters independently reviewed randomized sequences in a blinded fashion for adenoma characteristics and parasellar invasion. Subgroup analysis of hormonal remission was performed.

RESULTS

A total of 34 functioning pituitary adenoma patients were included (average age 39.3 ± 12.2; female n = 27), 30 of which had post-operative hormonal remission (n = 34; 88.2%). Compared to CE-T1WI, CE-CISS has significantly higher number of sequences rated "good" image quality (p = 0.02). Hormone remission was associated with decreased degrees of pre-operative internal carotid artery (ICA) contact and Knosp score (p ≤ 0.02) on all sequences except for Knosp score on T2WI. On receiver operating characteristic analysis, the area under curve for differentiating endocrine remission ranged from 0.88 to 0.92 for Knosp score and 0.85-0.93 for ICA contact, depending on sequence.

CONCLUSION

Extent of pituitary adenoma cavernous sinus invasion as measured by degrees of ICA contact and Knosp score is associated with postoperative endocrine outcomes. Given improved image quality, inclusion of CE-CISS may be helpful for pre-surgical planning.

Papilloedema from Dural Venous Sinus Compression by Meningiomas

Intracranial mass lesions may cause intracranial hypertension secondary to venous hypertension when they compress the dural venous sinuses (DVS) and may present with isolated papilloedema, mimicking idiopathic intracranial hypertension. We report a series of 16 patients with isolated papilloedema related to meningiomas compressing the DVS seen from 2012 to 2016 at three institutions. Correct diagnosis was delayed in 10/16 patients and treatment required a multidisciplinary approach, often with multiple sequential interventions, including combinations of acetazolamide, cerebrospinal fluid-shunt, optic nerve sheath fenestration, surgical resection of the meningioma, radiation therapy, and endovascular venous stenting. Two patients also received anticoagulation for venous thrombosis secondary to venous sinus compression.

Simultaneous perfusion and permeability assessments using multiband multi-echo EPI (M2-EPI) in brain tumors

PURPOSE

To study a multiband multi-echo EPI (M2-EPI) sequence for dynamic susceptibility contrast (DSC) perfusion imaging with leakage correction and vascular permeability measurements, and to evaluate the benefits of increased temporal resolution provided by this acquisition strategy on the accuracy of perfusion and permeability estimations.

METHODS

A novel M2-EPI sequence was developed, and a pharmacokinetic model accounting for contrast agent extravasation was used to produce perfusion maps and additional vascular permeability maps. The advantage of M2-EPI for DSC perfusion imaging was demonstrated in vivo in 5 patients with brain tumors, and numerical simulations were performed to evaluate the advantage of improved temporal resolution afforded by the technique.

RESULTS

In contrast to underestimations of cerebral blood volume (CBV) in tumors using the single-echo acquisition strategy, M2-EPI provided more plausible estimates of CBV. A quantitative evaluation showed higher estimated values of CBV and mean transit time in tumor tissues using M2-EPI (CBV: 3.08 ± 0.78 mL/100 g versus 1.56 ± 1.38 mL/100 g [P = .006]; mean transit time: 4.94 ± 1.17 seconds versus 1.83 ± 2.06 seconds [P = 0.033]). Numerical simulations showed that higher temporal resolution provided by M2-EPI was associated with more accurate estimates of cerebral blood flow, CBV, and permeability parameters.

CONCLUSION

The novel M2-EPI acquisition strategy for DSC imaging facilitates leakage-corrected perfusion measurements with additional permeability assessments and more accurate estimates of perfusion/permeability parameters, and may be used as a quantitative tool for the diagnosis, prognosis, and treatment monitoring of brain tumors.

Stereotactic laser amygdalohippocampotomy for mesial temporal lobe epilepsy

OBJECTIVE

To evaluate the outcomes 1 year and longer following stereotactic laser amygdalohippocampotomy for mesial temporal lobe epilepsy in a large series of patients treated over a 5-year period since introduction of this novel technique.

METHODS

Surgical outcomes of a consecutive series of 58 patients with mesial temporal lobe epilepsy who underwent the surgery at our institution with at least 12 months of follow-up were retrospectively evaluated. A subgroup analysis was performed comparing patients with and without mesial temporal sclerosis.

RESULTS

One year following stereotactic laser amygdalohippocampotomy, 53.4% (95% confidence interval [CI] = 40.8-65.7%) of all patients were free of disabling seizures (Engel I). Three of 9 patients became seizure-free following repeat ablation. Subgroup analysis showed that 60.5% (95% CI = 45.6-73.7%) of patients with mesial temporal sclerosis were free of disabling seizures as compared to 33.3% (95% CI = 15.0-58.5%) of patients without mesial temporal sclerosis. Quality of Life in Epilepsy-31 scores significantly improved at the group level, few procedure-related complications were observed, and verbal memory outcome was better than historical open resection data.

INTERPRETATION

In an unselected consecutive series of patients, stereotactic laser amygdalohippocampotomy yielded seizure-free rates for patients with mesial temporal lobe epilepsy lower than, but comparable to, the outcomes typically associated with open temporal lobe surgery. Analogous to results from open surgery, patients without mesial temporal sclerosis fared less well. This novel procedure is an effective minimally invasive alternative to resective surgery. In the minority of patients not free of disabling seizures, laser ablation presents no barrier to additional open surgery. Ann Neurol 2018;83:575-587.

Noninvasive Assessment of Intracranial Pressure Status in Idiopathic Intracranial Hypertension Using Displacement Encoding with Stimulated Echoes (DENSE) MRI: A Prospective Patient Study with Contemporaneous CSF Pressure Correlation

BACKGROUND AND PURPOSE

Intracranial pressure is estimated invasively by using lumbar puncture with CSF opening pressure measurement. This study evaluated displacement encoding with stimulated echoes (DENSE), an MR imaging technique highly sensitive to brain motion, as a noninvasive means of assessing intracranial pressure status.

MATERIALS AND METHODS

Nine patients with suspected elevated intracranial pressure and 9 healthy control subjects were included in this prospective study. Controls underwent DENSE MR imaging through the midsagittal brain. Patients underwent DENSE MR imaging followed immediately by lumbar puncture with opening pressure measurement, CSF removal, closing pressure measurement, and immediate repeat DENSE MR imaging. Phase-reconstructed images were processed producing displacement maps, and pontine displacement was calculated. Patient data were analyzed to determine the effects of measured pressure on pontine displacement. Patient and control data were analyzed to assess the effects of clinical status (pre-lumbar puncture, post-lumbar puncture, or control) on pontine displacement.

RESULTS

Patients demonstrated imaging findings suggesting chronically elevated intracranial pressure, whereas healthy control volunteers demonstrated no imaging abnormalities. All patients had elevated opening pressure (median, 36.0 cm water), decreased by the removal of CSF to a median closing pressure of 17.0 cm water. Patients pre-lumbar puncture had significantly smaller pontine displacement than they did post-lumbar puncture after CSF pressure reduction (P = .001) and compared with controls (P = .01). Post-lumbar puncture patients had statistically similar pontine displacements to controls. Measured CSF pressure in patients pre- and post-lumbar puncture correlated significantly with pontine displacement (r = 0.49; P = .04).

CONCLUSIONS

This study establishes a relationship between pontine displacement from DENSE MR imaging and measured pressure obtained contemporaneously by lumbar puncture, providing a method to noninvasively assess intracranial pressure status in idiopathic intracranial hypertension.

Degree of Vascular Encasement in Sphenoid Wing Meningiomas Predicts Postoperative Ischemic Complications

BACKGROUND

Sphenoid wing meningiomas (SWMs) can encase arteries of the circle of Willis, increasing their susceptibility to intraoperative vascular injury and severe ischemic complications.

OBJECTIVE

To demonstrate the effect of circumferential vascular encasement in SWM on postoperative ischemia.

METHODS

A retrospective review of 75 patients surgically treated for SWM from 2009 to 2015 was undertaken to determine the degree of circumferential vascular encasement (0°-360°) as assessed by preoperative magnetic resonance imaging (MRI). A novel grading system describing "maximum" and "total" arterial encasement scores was created. Postoperative MRIs were reviewed for total ischemia volume measured on sequential diffusion-weighted images.

RESULTS

Of the 75 patients, 89.3% had some degree of vascular involvement with a median maximum encasement score of 3.0 (2.0-3.0) in the internal carotid artery (ICA), M1, M2, and A1 segments; 76% of patients had some degree of ischemia with median infarct volume of 3.75 cm 3 (0.81-9.3 cm 3 ). Univariate analysis determined risk factors associated with larger infarction volume, which were encasement of the supraclinoid ICA ( P < .001), M1 segment ( P < .001), A1 segment ( P = .015), and diabetes ( P = .019). As the maximum encasement score increased from 1 to 5 in each of the significant arterial segments, so did mean and median infarction volume ( P < .001). Risk for devastating ischemic injury >62 cm 3 was found when the ICA, M1, and A1 vessels all had ≥360° involvement ( P = .001). Residual tumor was associated with smaller infarct volumes ( P = .022). As infarction volume increased, so did modified Rankin Score at discharge ( P = .025).

CONCLUSION

Subtotal resection should be considered in SWM with significant vascular encasement of proximal arteries to limit postoperative ischemic complications.

Imaging of Intracranial Pressure Disorders

Intracranial pressure (ICP) is the pressure inside the bony calvarium and can be affected by a variety of processes, such as intracranial masses and edema, obstruction or leakage of cerebrospinal fluid, and obstruction of venous outflow. This review focuses on the imaging of 2 important but less well understood ICP disorders: idiopathic intracranial hypertension and spontaneous intracranial hypotension. Both of these ICP disorders have salient imaging findings that are important to recognize to help prevent their misdiagnosis from other common neurological disorders.

Imaging Features of Idiopathic Intracranial Hypertension in Children

Magnetic resonance imaging (MRI) signs of elevated intracranial pressure and idiopathic intracranial hypertension have been well characterized in adults but not in children. The MRIs of 50 children with idiopathic intracranial hypertension and 46 adults with idiopathic intracranial hypertension were reviewed for optic nerve head protrusion, optic nerve head enhancement, posterior scleral flattening, increased perioptic cerebrospinal fluid, optic nerve tortuosity, empty or partially empty sella, tonsillar herniation, enlargement of Meckel's cave meningoceles, and transverse venous sinus stenosis(TSS). Compared to adolescents (11-17 years, n = 40) and adults (>17 years, n = 46), prepubescent children (<11 years, n = 10) had lower frequencies of scleral flattening (50% vs 89% and 85%, P = .02), increased perioptic cerebrospinal fluid (60% vs 84% and 89%, P = .08), optic nerve tortuosity (20% vs 46% and 59%, P = .07), empty or partially empty sella (56% vs 78% and 93%, P = .007), and TSS (67% vs 93% and 96%, P = .04). Children with idiopathic intracranial hypertension have similar MRI findings as adults, but they are less frequent in prepubescent children.

Utility of double inversion recovery MRI in paediatric epilepsy

Detecting focal abnormalities in MRI examinations of children with epilepsy can be a challenging task given the frequently subtle appearance of cortical dysplasia, mesial temporal sclerosis and similar lesions. In this report, we demonstrate the utility of double inversion recovery MRI in the detection of paediatric epileptogenic abnormalities, promoted primarily by increased lesion conspicuity due to complementary suppression of both cerebrospinal fluid and normal white matter signal.

Magnetic Resonance Thermometry-Guided Stereotactic Laser Ablation of Cavernous Malformations in Drug-Resistant Epilepsy: Imaging and Clinical Results

BACKGROUND

Surgery is indicated for cerebral cavernous malformations (CCM) that cause medically refractory epilepsy. Real-time magnetic resonance thermography (MRT)-guided stereotactic laser ablation (SLA) is a minimally invasive approach to treating focal brain lesions. SLA of CCM has not previously been described.

OBJECTIVE

To describe MRT-guided SLA, a novel approach to treating CCM-related epilepsy, with respect to feasibility, safety, imaging, and seizure control in 5 consecutive patients.

METHODS

Five patients with medically refractory epilepsy undergoing standard presurgical evaluation were found to have corresponding lesions fulfilling imaging characteristics of CCM and were prospectively enrolled. Each underwent stereotactic placement of a saline-cooled cannula containing an optical fiber to deliver 980-nm diode laser energy via twist drill craniostomy. MR anatomic imaging was used to evaluate targeting prior to ablation. MR imaging provided evaluation of targeting and near real-time feedback regarding extent of tissue thermocoagulation. Patients maintained seizure diaries, and remote imaging (6-21 months post-ablation) was obtained in all patients.

RESULTS

Imaging revealed no evidence of acute hemorrhage following fiber placement within presumed CCM. MRT during treatment and immediate post-procedure imaging confirmed desired extent of ablation. We identified no adverse events or neurological deficits. Four of 5 (80%) patients achieved freedom from disabling seizures after SLA alone (Engel class 1 outcome), with follow-up ranging 12-28 months. Reimaging of all subjects (6-21 months) indicated lesion diminution with surrounding liquefactive necrosis, consistent with the surgical goal of extended lesionotomy.

CONCLUSION

Minimally invasive MRT-guided SLA of epileptogenic CCM is a potentially safe and effective alternative to open resection. Additional experience and longer follow-up are needed.

The brain connectome as a personalized biomarker of seizure outcomes after temporal lobectomy

OBJECTIVE

We examined whether individual neuronal architecture obtained from the brain connectome can be used to estimate the surgical success of anterior temporal lobectomy (ATL) in patients with temporal lobe epilepsy (TLE).

METHODS

We retrospectively studied 35 consecutive patients with TLE who underwent ATL. The structural brain connectome was reconstructed from all patients using presurgical diffusion MRI. Network links in patients were standardized as Z scores based on connectomes reconstructed from healthy controls. The topography of abnormalities in linkwise elements of the connectome was assessed on subnetworks linking ipsilateral temporal with extratemporal regions. Predictive models were constructed based on the individual prevalence of linkwise Z scores >2 and based on presurgical clinical data.

RESULTS

Patients were more likely to achieve postsurgical seizure freedom if they exhibited fewer abnormalities within a subnetwork composed of the ipsilateral hippocampus, amygdala, thalamus, superior frontal region, lateral temporal gyri, insula, orbitofrontal cortex, cingulate, and lateral occipital gyrus. Seizure-free surgical outcome was predicted by neural architecture alone with 90% specificity (83% accuracy), and by neural architecture combined with clinical data with 94% specificity (88% accuracy).

CONCLUSIONS

Individual variations in connectome topography, combined with presurgical clinical data, may be used as biomarkers to better estimate surgical outcomes in patients with TLE.

Better object recognition and naming outcome with MRI-guided stereotactic laser amygdalohippocampotomy for temporal lobe epilepsy

OBJECTIVES

Patients with temporal lobe epilepsy (TLE) experience significant deficits in category-related object recognition and naming following standard surgical approaches. These deficits may result from a decoupling of core processing modules (e.g., language, visual processing, and semantic memory), due to "collateral damage" to temporal regions outside the hippocampus following open surgical approaches. We predicted that stereotactic laser amygdalohippocampotomy (SLAH) would minimize such deficits because it preserves white matter pathways and neocortical regions that are critical for these cognitive processes.

METHODS

Tests of naming and recognition of common nouns (Boston Naming Test) and famous persons were compared with nonparametric analyses using exact tests between a group of 19 patients with medically intractable mesial TLE undergoing SLAH (10 dominant, 9 nondominant), and a comparable series of TLE patients undergoing standard surgical approaches (n=39) using a prospective, nonrandomized, nonblinded, parallel-group design.

RESULTS

Performance declines were significantly greater for the patients with dominant TLE who were undergoing open resection versus SLAH for naming famous faces and common nouns (F=24.3, p<0.0001, η2=0.57, and F=11.2, p<0.001, η2=0.39, respectively), and for the patients with nondominant TLE undergoing open resection versus SLAH for recognizing famous faces (F=3.9, p<0.02, η2=0.19). When examined on an individual subject basis, no SLAH patients experienced any performance declines on these measures. In contrast, 32 of the 39 patients undergoing standard surgical approaches declined on one or more measures for both object types (p<0.001, Fisher's exact test). Twenty-one of 22 left (dominant) TLE patients declined on one or both naming tasks after open resection, while 11 of 17 right (nondominant) TLE patients declined on face recognition.

SIGNIFICANCE

Preliminary results suggest (1) naming and recognition functions can be spared in TLE patients undergoing SLAH, and (2) the hippocampus does not appear to be an essential component of neural networks underlying name retrieval or recognition of common objects or famous faces.

Patterns of presentation and failure in patients with gliomatosis cerebri treated with partial-brain radiation therapy

BACKGROUND

The patterns of lobar involvement, optimal treatment, and disease course among patients with gliomatosis cerebri (GC) have not been fully characterized. The current study evaluates the clinical presentations and outcomes for patients with GC treated with radiation therapy (RT) at our institution.

METHODS

A total of 26 patients (25 with follow-up) with GC were diagnosed and treated between January 2004 and June 2012. Inclusion criteria consisted of brain magnetic resonance imaging and neuroradiology confirmation of contiguous involvement of ≥ 3 lobes/lobar equivalents with preservation of neural architecture. Patients were treated with either partial-brain RT to involved tumor (25 patients) or whole-brain RT (1 patient). The median RT dose was 54.0 Gray. The median follow-up was 17.3 months.

RESULTS

The median age of the patients at the time of diagnosis was 57 years. Twenty-one patients (81%) and 5 patients (19%) had 3 to 6 and ≥ 7 involved lobes/lobar equivalents, respectively. The median progression-free survival and overall survival were 7.4 months and 14.9 months, respectively. Fifteen patients experienced radiographic disease progression after partial-brain RT, 14 of whom (93%) developed infield disease recurrence. On univariate analysis, higher tumor grade and type II GC (with focal mass) were associated with a poorer progression-free survival. The extent of lobar involvement and chemotherapy were not associated with overall survival.

CONCLUSIONS

Even with partial-brain RT, nearly all disease recurrences were infield and clinical outcomes were similar to previous GC series, thereby suggesting that whole-brain RT is not necessary for this patient population. A greater number of involved lobes did not correlate with inferior outcomes. Further studies are necessary to establish more uniform and optimal treatments for this rare disease.

Fluoroscopic-guided lumbar puncture: fluoroscopic time and implications of body mass index--a baseline study

BACKGROUND AND PURPOSE

Fluoroscopic-guided lumbar puncture is an effective alternative to bedside lumbar puncture in challenging patients. However, no published guidelines are available for an acceptable range of fluoroscopic time for this procedure. The purpose of this study was to set department benchmark fluoroscopic times for lumbar puncture, accounting for body mass index in our patient population.

MATERIALS AND METHODS

We identified and reviewed all patients who underwent fluoroscopic-guided lumbar puncture at 4 hospitals during a 2-year period (July 2011 to June 2013). Data collection included patient information (demographics, body mass index, history of prior lumbar surgery and/or lumbar hardware, scoliosis); procedure details (fluoroscopic time, level of access, approach, needle gauge and length); level of operator experience; and hospital site. A generalized linear model was used to test whether body mass index influenced fluoroscopic time while controlling other factors.

RESULTS

Five hundred eighty-four patients (mean age, 47.8 ± 16.2 years; range, 16-92 years; 33% male) had successful fluoroscopic-guided lumbar puncture s. Mean body mass index and fluoroscopic time were higher in female patients (34.4 ± 9.9 kg/m(2) and 1.07 minutes; 95% CI, 0.95-1.20) than in male patients (29.2 ± 7.3 kg/m(2) and 0.91 minutes; 95% CI, 0.79-1.03). Body mass index (P = .001), hospital site (P < .001), and level of experience (P = .03) were factors significantly affecting fluoroscopic time on multivariate analysis. Benchmark fluoroscopic times in minutes were the following: 0.48 (95% CI, 0.40-0.56) for normal, 0.61 for overweight (95% CI, 0.52-0.71), 0.63(95% CI, 0.58-0.73) for obese, and 0.86 (95% CI, 0.74-1.01) in extremely obese body mass index categories.

CONCLUSIONS

In patients undergoing fluoroscopic-guided lumbar punctures, fluoroscopy time increased with body mass index We established benchmark fluoroscopic-guided lumbar puncture time ranges as related to body mass index in our patient population.

Contrast-enhanced time-resolved MRA for follow-up of intracranial aneurysms treated with the pipeline embolization device

BACKGROUND AND PURPOSE

Endovascular reconstruction and flow diversion by using the Pipeline Embolization Device is an effective treatment for complex cerebral aneurysms. Accurate noninvasive alternatives to DSA for follow-up after Pipeline Embolization Device treatment are desirable. This study evaluated the accuracy of contrast-enhanced time-resolved MRA for this purpose, hypothesizing that contrast-enhanced time-resolved MRA will be comparable with DSA and superior to 3D-TOF MRA.

MATERIALS AND METHODS

During a 24-month period, 37 Pipeline Embolization Device-treated intracranial aneurysms in 26 patients underwent initial follow-up by using 3D-TOF MRA, contrast-enhanced time-resolved MRA, and DSA. MRA was performed on a 1.5T unit by using 3D-TOF and time-resolved imaging of contrast kinetics. All patients underwent DSA a median of 0 days (range, 0-68) after MRA. Studies were evaluated for aneurysm occlusion, quality of visualization of the reconstructed artery, and measurable luminal diameter of the Pipeline Embolization Device, with DSA used as the reference standard.

RESULTS

The sensitivity, specificity, and positive and negative predictive values of contrast-enhanced time-resolved MRA relative to DSA for posttreatment aneurysm occlusion were 96%, 85%, 92%, and 92%. Contrast-enhanced time-resolved MRA demonstrated superior quality of visualization (P = .0001) and a higher measurable luminal diameter (P = .0001) of the reconstructed artery compared with 3D-TOF MRA but no significant difference compared with DSA. Contrast-enhanced time-resolved MRA underestimated the luminal diameter of the reconstructed artery by 0.965 ± 0.497 mm (27% ± 13%) relative to DSA.

CONCLUSIONS

Contrast-enhanced time-resolved MRA is a reliable noninvasive method for monitoring intracranial aneurysms following flow diversion and vessel reconstruction by using the Pipeline Embolization Device.