Sanjiv Bhatia

Measurement of whole temporal lobe and hippocampus for MR volumetry Normative data

We measured the volumes of the entire length of temporal lobe and hippocampal formation from coronal images in 29 healthy young adults to take into account normal side-to-side variation. Although whole-brain, temporal lobe, and left hippocampal volumes were significantly smaller in women, normalizing measurements for the whole brain eliminated intersex temporal lobe and hippocampal differences. There was a weak but significant inverse correlation between age and normalized hippocampal, but not temporal lobe or whole-brain, volume. In contrast to previous studies, we found no significant side-to-side differences in the sizes of temporal lobes or hippocampi. When performing MR volumetry, it is important to include the entire length of the hippocampal formation.

FDG-PET and volumetric MRI in the evaluation of patients with partial epilepsy

Article abstract-We performed interictal FDG-PET- and MRI-based hippocampal volumetric measurements on 18 adult patients with complex partial epilepsy of temporal lobe origin in whom we had identified their ictal focus by video-telemetry EEG. Sixteen patients (89%) had regional hypometabolism, 11 (61%) had focal 1.5-tesla T2-weighted MRI (two structural abnormalities, nine hippocampal formation (HF) increased T2 signal), and nine (50%) had absolute HF atrophy ipsilateral to the temporal ictal focus. Ten (55%) had abnormal L/R HF ratios, nine ipsilateral to the EEG focus. All patients with abnormal MRI volumetric studies had focal PET abnormalities. Only seven had both abnormal HF volume ratios and T2 MRI (all increased HF T2 signal). There was a significant correlation between hippocampal volume and inferior mesial and lateral temporal lobe cerebral metabolic rate of glucose asymmetry index (p < 0.01), suggesting that hypometabolism may reflect hippocampal atrophy. PET is more sensitive than MRI volumetry in identifying the ictal focus but does not provide additional information when HF atrophy is present. NEUROLOGY 1995;45: 123-126

Epilepsy surgery in patients with normal or nonfocal MRI scans: Integrative strategies offer long‐term seizure relief

Purpose: Excisional surgery achieves seizure freedom in a large proportion of children with intractable lesional epilepsy, but the outcome for children without a focal lesion on MRI is less clear. We report the outcome of a cohort predominantly of children with nonlesional intractable partial epilepsy undergoing resective surgery.

MR-guided laser interstitial thermal therapy for pediatric drug-resistant lesional epilepsy

To report the feasibility, safety, and clinical outcomes of an exploratory study of MR‐guided Laser Interstitial Thermal Therapy (MRgLITT) as a minimally invasive surgical procedure for the ablation of epileptogenic foci in children with drug‐resistant, lesional epilepsy.

Outcomes in pediatric patients with Chiari malformation Type I followed up without surgery: Clinical article

OBJECT The natural history of untreated Chiari malformation Type I (CM-I) is poorly defined. The object of this study was to investigate outcomes in pediatric patients with CM-I who were followed up without surgical intervention. METHODS The authors retrospectively reviewed 124 cases involving patients with CM-I who presented between July 1999 and July 2008 and were followed up without surgery. The patients ranged in age from 0.9 to 19.8 years (mean 7 years). The duration of follow-up ranged from 1.0 to 8.6 years (mean 2.83 years). Imaging findings, symptoms, and findings on neurological examinations were noted at presentation and for the duration of follow-up. RESULTS The mean extent of tonsillar herniation at presentation was 8.35 mm (range 5-22 mm). Seven patients had a syrinx at presentation. The syrinx size did not change in these patients on follow-up imaging studies. No new syrinxes developed in the remaining patients who underwent subsequent imaging. The total number of patients with presenting symptoms was 81. Of those 81 patients, 67 demonstrated symptoms that were not typical of CM-I. Of the 14 patients with symptoms attributed to CM-I, 9 had symptoms that were not severe or frequent enough to warrant surgery, and surgery was recommended in the remaining 5 patients. Chiari malformation Type I was also diagnosed in 43 asymptomatic patients who had imaging studies performed for various reasons. No new neurological deficits were noted in any patient for the duration of follow-up. CONCLUSIONS The majority of patients with CM-I who are followed up without surgery do not progress clinically or radiologically. Longer follow-up of this cohort will be required to determine if symptoms or new neurological findings develop over the course of many years.

Endoscopic Fenestration of Middle Fossa Arachnoid Cysts: A Technical Description and Case Series

Background: Arachnoid cysts are intra-arachnoidal cerebrospinal fluid collections most frequently seen in the middle cranial fossa. The optimal method of treatment for symptomatic arachnoid cysts remains controversial and includes cyst shunting, open craniotomy and endoscopic fenestration. All these techniques, however, have been associated with the development of postoperative subdural fluid collections. We describe a new endoscopic transcortical technique that attempts to avoid this complication. Methods: Six patients with middle cranial fossa arachnoid cysts were treated with endoscopic fenestration at our institution between January 2002 and December 2005. Three cases were approached directly through the cyst, while the other 3 were approached by passing the endoscope through the rim of adjacent cortex. Results: All six endoscopic fenestrations were successful in treating the arachnoid cysts. Among the 3 patients treated via a direct cyst entry, 2 cases developed significant subdural hygromas, 1 of which required aspiration. On the other hand, 1 of the 3 cases treated using a transcortical technique developed an insignificant postoperative extra-axial collection that resolved at 3 months without intervention. Conclusion: Endoscopic fenestration is an effective treatment for symptomatic arachnoid cysts. Endoscopic fenestration via a transcortical approach attempts to minimize cerebrospinal fluid drainage into the subdural space, avoiding the development of significant postoperative extra-axial collections, while promoting flow into the basal cisterns.

Neurogenic stunned myocardium after acute hydrocephalus

Neurogenic stunned myocardium (NSM) is a syndrome of cardiac stunning after a neurological insult. It is commonly observed after aneurysmal subarachnoid hemorrhage but is increasingly being reported after other neurological events. The underlying mechanism of NSM is believed to be a hypothalamic-mediated sympathetic surge causing weakened cardiac contractility and even direct cardiac myocyte damage. The authors report 2 cases of NSM in pediatric patients after acute hydrocephalus. Both patients experienced severe cardiac dysfunction in the acute phase but ultimately had a good neurological outcome and a full cardiac recovery. The identification, treatment, and outcome in 2 rare pediatric cases of NSM are discussed, and the history of the brain-cardiac connection is reviewed.

Endoscopic third ventriculostomy and choroid plexus cauterization in posthemorrhagic hydrocephalus of prematurity.

OBJECT The aim of this study was to determine the role of endoscopic third ventriculostomy and choroid plexus cauterization (ETV/CPC) in the management of posthemorrhagic hydrocephalus of prematurity (PHHP) and to analyze which factors affect patient outcomes. METHODS This study retrospectively reviewed medical records of 27 premature infants with intraventricular hemorrhage (IVH) and hydrocephalus treated with ETV and CPC from 2008 to 2011. All patients were evaluated using MRI before the procedure to verify the anatomical feasibility of ETV/CPC. Endoscopic treatment included third ventriculostomy, septostomy, and bilateral CPC. After ETV/CPC, all patients underwent follow-up for a period of 6-40 months (mean 16.2 months). The procedure was considered a failure if the patient subsequently required a shunt. The following factors were analyzed to determine a relationship to patient outcomes: gestational age at birth, corrected age and weight at surgery, timing of surgery after birth, grade of IVH, the status of the prepontine cistern and cerebral aqueduct on MRI, need for a ventricular access device prior to the endoscopic procedure, and scarring of the prepontine cistern noted at surgery. RESULTS Seventeen (63%) of 27 patients required a shunt after ETV/CPC, and 10 patients did not require further CSF diversion. Several factors studied were associated with a higher rate of ETV/CPC failure: Grade IV hemorrhage, weight 3 kg or less and age younger than 3 months at the time of surgery, need for reservoir placement, and presence of a normal cerebral aqueduct. Two factors were found to be statistically significant: the patients corrected gestational age of less than 0 weeks at surgery and a narrow prepontine cistern on MRI. The majority (83%) of ETV/CPC failures occurred in the first 3 months after the procedure. None of the patients had a complication directly related to the procedure. CONCLUSIONS Endoscopic third ventriculostomy/CPC is a safe initial procedure for hydrocephalus in premature infants with IVH and hydrocephalus, obviating the need for a shunt in selected patients. Even though the success rate is low (37%), the lower rate of complications in comparison with shunt treatment may justify this procedure in the initial management of hydrocephalus. As several of the studied factors have shown influence on the outcome, patient selection based on these observations might increase the success rate.

Predictors of seizure freedom after incomplete resection in children

Objective: Incomplete resection of the epileptogenic zone (EZ) is the most important predictor of poor outcome after resective surgery for intractable epilepsy. We analyzed the contribution of preoperative and perioperative variables including MRI and EEG data as predictors of seizure-free (SF) outcome after incomplete resection. Methods: We retrospectively reviewed patients <18 years of age with incomplete resection for epilepsy with 2 years of follow-up. Fourteen preoperative and perioperative variables were compared in SF and non-SF (NSF) patients. We compared lesional patients, categorized by reason for incompleteness, to lesional patients with complete resection. We analyzed for effect of complete EEG resection on SF outcome in patients with incompletely resected MRI lesions and vice versa. Results: Eighty-three patients with incomplete resection were included with 41% becoming SF. Forty-eight lesional patients with complete resection were included. Thirty-eight percent (57/151) of patients with incomplete resection and 34% (47/138) with complete resection were excluded secondary to lack of follow-up or incomplete records. Contiguous MRI lesions were predictive of seizure freedom after incomplete resection. Fifty-seven percent of patients incomplete by MRI alone, 52% incomplete by EEG alone, and 24% incomplete by both became SF compared to 77% of patients with complete resection (p = 0.0005). Conclusions: Complete resection of the MRI- and EEG-defined EZ is the best predictor of seizure freedom, though patients incomplete by EEG or MRI alone have better outcome compared to patients incomplete by both. More than one-third of patients with incomplete resection become SF, with contiguous MRI lesions a predictor of SF outcome.

Diffuse reflectance spectroscopy for in vivo pediatric brain tumor detection

The concept of using diffuse reflectance spectroscopy to distinguish intraoperatively between pediatric brain tumors and normal brain parenchyma at the edge of resection cavities is evaluated using an in vivo human study. Diffuse reflectance spectra are acquired from normal and tumorous brain areas of 12 pediatric patients during their tumor resection procedures, using a spectroscopic system with a handheld optical probe. A total of 400 spectra are acquired at the rate of 33 Hz from a single investigated site, from which the mean spectrum and the standard deviation are calculated. The mean diffuse reflectance spectra collected are divided into the normal and the tumorous categories in accordance with their corresponding results of histological analysis. Statistical methods are used to identify those spectral features that effectively separated the two tissue categories, and to quantify the spectral variations induced by the motion of the handheld probe during a single spectral acquisition procedure. The results show that diffuse reflectance spectral intensities between 600 and 800 nm are effective in terms of differentiating normal cortex from brain tumors. Furthermore, probe movements induce large variations in spectral intensities (i.e., larger standard deviation) between 400 and 600 nm.