Role of Magnetic Resonance Imaging in the Screening of Closed Spinal Dysraphism.

Closed spinal dysraphism (CSD) encompasses a heterogeneous group of spinal cord deformities, which can be accompanied by several types of skin stigmata. These skin stigmata may include inconspicuous features, such as sacral dimples and deformed gluteal clefts, but the association between such mild skin stigmata and CSD is uncertain. This study aimed to reevaluate the indication for magnetic resonance imaging (MRI) in patients with skin stigmata while considering the indication for surgery. A retrospective analysis was conducted on magnetic resonance images of 1255 asymptomatic children with skin stigmata between 2003 and 2015. Skin stigmata classification was based on medical chart data. All subtypes of CSDs except for filum terminale lipomas (FTL), FTL thicker than 2 mm or with low conus medullaris, were considered to meet the surgical indication. CSD prevalence was estimated while considering the surgical indications and assessed after excluding all FTL cases. Skin stigmata were classified into seven types, dimple, deformed gluteal cleft, hair, subcutaneous mass, appendage, discoloration, and protruding bone, and included 1056 isolated and 199 complex ones. The prevalence of CSD was 19.5%, 6.8%, and 0.5% among patients with isolated dimples (n = 881) and 13.9%, 5.8%, and 0.7% among those with isolated deformed gluteal clefts (n = 136) for all cases, surgical indications, and patients without FTL, respectively. Dimples and deformed gluteal clefts had a low prevalence of CSD requiring surgical intervention, and cases without FTL were rare. Asymptomatic patients with mild skin stigmata may not require immediate MRI.

[Surgery for Spinal Lipoma of the Conus Medullaris].

Lipoma of the conus medullaris(LCM)can cause neurological symptoms known as tethered cord syndrome(TCS). The symptoms can be seen at diagnosis and during long-term follow-up. Even after surgical treatment, some patients can present with neurological deterioration indicating a TCS, defined as retethered cord syndrome(ReTCS). In this report the surgical technique for conus lipoma comprising wide osteoplastic laminotomy with confirmed whole spinal lipoma and adjacent normal spinal tissue is described, with dissection performed from the proximal side to the distal side with confirmed normal spinal cord and roots under operative microscope, expansive dural plasty aiming to get low cord/sac ratio was reported. Considering that some patients with LCM show postoperative neurological symptoms due to TCS in a long-term follow-up period, careful postoperative follow-up is necessary.

[Moyamoya Disease in Infants and Toddlers].

Treatment for moyamoya disease in infants and toddlers is challenging, because of the progressiveness of the disease. Revascularization surgery is the first-line therapy and should be performed as early as possible after diagnosis to prevent additional cerebral infarction. This review describes in detail the changes in the new "Diagnostic Criteria 2021 for moyamoya disease", and discusses the concept of treatment including indirect and combined bypass surgery in infants and toddlers. Surgical technique and perioperative management based on our experience are also precisely described.

Transcortical Endoscopic Removal of Residual Craniopharyngioma in the Third Ventricle: Surgical Video.

Excision through craniotomy is used for pediatric craniopharyngioma removal. However, residual tumors can sometimes be found in the blind spot of the microscopic field, such as the third ventricle wall, back of the optic chiasm, and brainstem surface, during surgery. Video 1 demonstrates the surgery using a flexible endoscope for the removal of residual tumor located within the blind spot of the first resection. The written consent was obtained from the patient's family. A 4-year-old child complained of vomiting, and the radiologic findings showed obstructive hydrocephalus and a calcified suprasellar mass lesion that extended to the third ventricle. The tumor was treated with a right frontotemporal craniotomy. The pathologic diagnosis was craniopharyngioma. Postoperative magnetic resonance imaging showed residual tumor detected at the roof of the third ventricle, back of the optic chiasm, and interpeduncular fossa. The residual tumors were removed using a flexible endoscope via a transcortical, transventricular approach. Postoperative magnetic resonance imaging showed no residual tumors. Although histologically benign, craniopharyngiomas may be locally aggressive and their close proximity to vital structures makes them one of our controversial management dilemmas. Recurrence may occur following even a presumed total excision and radiation therapy. Residual tumors located in the third ventricle are resected through various approaches, such as the transsphenoidal or transcallosal approach. Our approach using a flexible endoscope was minimally invasive and useful for the removal of residual tumor of the third ventricle in craniopharyngioma surgery because the approach offered a wide field of view and visual angle and forceps could be applied according to the view.

Ocular Ischemic Syndrome due to Internal Carotid Artery Occlusion with Neurofibromatosis Type 1.

Neurofibromatosis type 1 (NF-1) is associated with multiple vascular abnormalities, including internal carotid artery (ICA) stenosis/occlusion. Depending on the site of stenosis/occlusion of the ICA, both cerebral circulation and ocular circulation can be impaired. We describe a rare pediatric case of ocular ischemic syndrome (OIS) due to ICA occlusion in NF-1. The patient diagnosed with NF-1 suffered right ICA occlusion at 12 years of age, and developed right dense vitreous hemorrhage due to OIS at 13 years of age. The patient underwent right cerebral revascularization surgery to improve cerebral and ocular ischemia, but the visual acuity of the right eye did not improve. This case suggests that attention should be paid not only to cerebral ischemia but also to ocular ischemia in patients with ICA stenosis/occlusion of NF-1. Surgical interventions such as cerebral revascularization surgery should be considered in the early stages of OIS to protect visual function, and careful follow-up is required.

Retethering risk in pediatric spinal lipoma of the conus medullaris.

OBJECTIVE: Lipoma of the conus medullaris (LCM) causes neurological symptoms known as tethered cord syndrome (TCS). The symptoms can be seen at diagnosis and during long-term follow-up. In this report, pediatric patients with LCMs who underwent untethering surgery, under the policy of performing surgery if diagnosed regardless of symptoms, were retrospectively reviewed to evaluate long-term surgical outcomes. Possible risk factors for retethered cord syndrome (ReTCS) were evaluated in the long-term follow-up period. METHODS: A total of 51 consecutive pediatric patients with LCMs who underwent a first untethering surgery and were followed for > 100 months were retrospectively analyzed. The surgery was performed with the partial removal technique. Pre- and postoperative clinical and radiological data were reviewed to analyze the outcomes of surgery and identify potential risk factors for ReTCS. RESULTS: During follow-up, 12 patients experienced neurological deterioration due to ReTCS. The overall 10-year and 15-year progression-free survival rates were 82.3% and 75.1%, respectively. On univariate analysis, a lipoma type of lipomyelomeningocele (OR 11, 95% CI 2.50-48.4; p = 0.0014), patient age at the time of surgery (OR 0.41, 95% CI 0.14-1.18; p = 0.0070), and the mean patient growth rate after surgery (OR 2.00, 95% CI 1.12-3.41; p = 0.0040) were significant factors associated with ReTCS. Cox proportional hazard models showed that a lipoma type of lipomyelomeningocele (HR 5.16, 95% CI 1.54-20.1; p = 0.010) and the mean growth rate after surgery (HR 1.88, 95% CI 1.00-3.50; p = 0.040) were significantly associated with the occurrence of ReTCS. CONCLUSIONS: More complex lesions and a high patient growth rate after surgery seemed to indicate increased risk of ReTCS. Larger prospective studies and registries are needed to define the risks of ReTCS more adequately.

Preoperative Risks of Cerebral Infarction in Pediatric Moyamoya Disease.

Background and Purpose: In pediatric moyamoya disease, there have been few reports of the risk factors for preoperative cerebral infarction, especially during the waiting period before surgery. The clinical and radiological findings of surgically treated pediatric moyamoya patients were evaluated to analyze the risk factors for cerebral infarction seen from onset to surgery. Methods: Between August 2003 and September 2019, 120 hemispheres of 71 patients under 18 years of age with moyamoya disease were surgically treated by direct and indirect bypass procedures. The mean age of all surgical hemispheres at diagnosis was 6.7±3.9 years (6 months­17 years). The potential risk factors for preoperative infarction were examined statistically. Results: Multivariate logistic regression analysis showed that risk factors for infarction at the time of diagnosis were age at diagnosis (odds ratio [OR], 0.68 [95% CI, 0.57­0.82]; P<0.0001) and the magnetic resonance angiography (MRA) score (OR, 2.29 [95% CI, 1.40­3.75]; P=0.001). Univariate analysis showed that risk factors for infarction while waiting for surgery were age at diagnosis (OR, 0.61 [95% CI, 0.46­0.80]; P<0.0001), the MRA score (OR, 1.75 [95% CI, 1.26­2.41]; P=0.0003), and onset of infarction (OR, 40.4 [95% CI, 5.08­322.3]; P<0.0001). Multiple comparisons showed that patients under 4 years of age were at a significantly high risk of infarction at the time of diagnosis and while waiting for surgery. Time from diagnosis to surgery of >2 months was a significant risk factor for infarction while waiting for surgery in patients under 6 years of age. Conclusions: Young age at diagnosis and a high MRA score may be associated with rapid disease progression and result in preoperative infarction. We recommend that surgery be performed within 2 months of diagnosis for the patients under 4 years of age with a high MRA score (>5) and cerebral infarction. Further study is needed to define the optimal timing of surgery.

Reconversion to ventriculoperitoneal shunt following ventriculoatrial shunt malfunction in children.

PURPOSE: To analyze the long-term efficacy of the ventriculoatrial shunt (VAS) in pediatric patients with hydrocephalus, focusing on the atrial catheter and suitable revision procedures of the distal catheter following VAS malformation performed at our institution. METHODS: The authors retrospectively analyzed data of 28 pediatric patients under the age of 10 years who were treated with VAS for hydrocephalus and who had a follow-up period of at least 5 years. RESULTS: A total of 42 atrial tube revision procedures were performed in 28 patients during the study period. The median atrial tube survival time due to atrial tube obstruction was 2.32 years (n = 31, range: 0.4-8.08 years). Atrial tube survival time was shorter in younger children (p < 0.0001) and in children who were shorter in height (p = 0.0001). As a revision procedure following atrial tube malfunction, 22 (78.6%) out of the 28 patients who had an inserted VAS had the VAS reconversion into a VPS at the last follow-up. CONCLUSIONS: VAS can be a useful alternative to VPS, but it requires frequent atrial tube revisions, especially in younger children. Reconversion to VPS after VAS malfunction is a reasonable option and is associated with longer shunt survival time despite its previously observed difficulties.

Progressive Hydrocephalus after Endoscopic Third Ventriculostomy in Pediatric Patients with Blake's Pouch Cyst.

The pathophysiology and optimal treatment for hydrocephalus with Blake's pouch cyst (BPC) remain controversial. The authors present two pediatric cases of hydrocephalus associated with BPC, in which the patients' hydrocephalus progressed after endoscopic third ventriculostomy (ETV), despite a patent stoma of the third ventricular floor. Case 1: A 4-year-old girl with delayed gait development was diagnosed with BPC-associated hydrocephalus and received ETV. Postoperatively, the patient presented headaches and nausea. Computed tomography (CT) scans demonstrated larger ventricles than those observed on the preoperative images. Because phase-contrast cine magnetic resonance imaging (MRI) and constructive interference in steady state (CISS) MRI revealed patent cerebrospinal fluid (CSF) flow at the third ventricular floor level, a ventriculoperitoneal shunt (VPS) was placed using a programmable pressure valve to treat the hydrocephalus. Case 2: A 6-year-old girl with newly developed repeated convulsive seizures was diagnosed with BPC-associated hydrocephalus and received ETV. Phase-contrast cine MRI on the 5th postoperative day showed hyperdynamic CSF flow at the third ventricular floor level. She also developed vomiting and headache 6 weeks after ETV. CT scans demonstrated much larger tetraventricular hydrocephalus than that observed on the preoperative images. VPS placement improved her hydrocephalus. Referencing the previous literature, we discuss the CSF dynamics and the mechanism of BPC-associated hydrocephalus, focusing on the third ventricular floor bulging. We hope our experience will help elucidate the pathophysiology and treatment strategies for BPC-associated hydrocephalus.

Progressive Cerebral Ischemia and Intracerebral Hemorrhage after Indirect Revascularization for a Patient with Cerebral Proliferative Angiopathy.

We previously reported a patient with cerebral proliferative angiopathy (CPA) who showed cerebral ischemia in resting and acetazolamide-stressed N-isopropyl-p-[123I] iodoamphetamine single-photon emission computed tomography (123I-IMP-SPECT). At onset, the patient was treated conservatively. However, during the 2 years following initial onset, his hemiparesis and aphasia had gradually aggravated and his IQ scores were markedly decreased. MRI revealed progressive vascular proliferation and brain atrophy. 123I-IMP-SPECT showed more severely impaired cerebral blood flow (CBF) and cerebrovascular reactivity over the affected hemisphere. We performed an indirect revascularization to augment CBF; however, his neurological deficits were not improved and new arteriovenous shunts via extracranial-intracranial bypass were developed, followed by an asymptomatic small intracerebral hemorrhage. There are no reports on CPA patients who have shown cerebral hemorrhage after indirect revascularization. Treatments for CPA are still challenging and controversial. Cases with severe stenosis of the proximal arteries may benefit from indirect revascularization. But indirect bypass should not be indicated for such patients without main arterial stenosis, even if they have persistent ischemia.

Posterior cerebral artery stenosis and posterior circulation revascularization surgery in pediatric patients with moyamoya disease.

OBJECTIVE Some pediatric patients with moyamoya disease (MMD) present with posterior cerebral artery (PCA) stenosis before and after anterior circulation revascularization surgery and require posterior circulation revascularization surgery. This study evaluated the factors associated with PCA stenosis and assessed the efficacy of posterior circulation revascularization surgery, including occipital artery (OA)-PCA bypass, in pediatric patients with MMD. METHODS The presence of PCA stenosis before and after anterior circulation revascularization surgery and its clinical characteristics were investigated in 62 pediatric patients (< 16 years of age) with MMD. RESULTS Twenty-three pediatric patients (37%) with MMD presented with PCA stenosis at the time of the initial diagnosis. A strong correlation between the presence of infarction and PCA stenosis before anterior revascularization was observed (p < 0.001). In addition, progressive PCA stenosis was observed in 12 patients (19.4%) after anterior revascularization. The presence of infarction and a younger age at the time of initial diagnosis were risk factors for progressive PCA stenosis after anterior revascularization (p < 0.001 and p = 0.002, respectively). Posterior circulation revascularization surgery, including OA-PCA bypass, was performed in 9 of the 12 patients with progressive PCA stenosis, all of whom showed symptomatic and/or radiological improvement. CONCLUSIONS PCA stenosis is an important clinical factor related to poor prognosis in pediatric MMD. One should be aware of the possibility of progressive PCA stenosis during the postoperative follow-up period and consider performing posterior circulation revascularization surgery.

Minimally Invasive Surgical Approach to Filum Lipoma.

Filum terminale lipoma (FTL) causes various spinal symptoms known as tethered cord syndrome. The treatment for FTL is surgical untethering by sectioning the FTL, which can prevent symptom progression and often results in improvement of symptoms. This report describes a minimally invasive surgical strategy that we have introduced for FTL sectioning. The pediatric patients with FTL since 2007 were treated using this minimally invasive surgical strategy, which we refer to as an interlaminar approach (ILA). In summary, the surgical technique involves: minimal skin incision to expose the unilateral ligamentum flavum in the lower lumbar region; ligamentum flavum incision to expose the dural sac, and dural incision followed by identification and sectioning of the filum. Postoperatively, no bed rest was required. Prior to introducing ILA, we had used standard one level laminectomy/laminotomy (LL) with more than 1 week of postsurgical bed rest until 2007, providing an adequate control group for the benefit of the ILA. A total of 49 consecutive patients were treated using ILA. While 37 patients were treated using LL. Surgical complications that need surgery were seen only in one patient, who developed cerebrospinal fluid (CSF) leak in LL patients. No retethering or additional neurological symptoms were seen during follow-up. All patients complained of minimal postsurgical back pain, but no patients required postoperative bed rest in ILA patients, while LL patients need postsurgical bed rest because of back pain. The ILA strategy provides the advantage of a minimal tissue injury, associated with minimal postoperative pain, blood loss, and bed rest.

Shunt placement after cyst fenestration for middle cranial fossa arachnoid cysts in children.

OBJECT Some pediatric patients with middle cranial fossa arachnoid cysts present with symptoms of increased intracranial pressure (ICP) and require shunt placement after a cyst fenestration. However, factors concerning increased ICP after fenestration followed by shunt placement have not been elucidated. This study evaluated factors that are associated with shunt placement following cyst fenestration in pediatric patients with middle cranial fossa arachnoid cysts. METHODS Twenty-six pediatric patients with middle cranial fossa arachnoid cysts who were surgically treated at a single institution between 2004 and 2013 were retrospectively identified. The surgical indications for middle cranial fossa arachnoid cysts were as follows: 1) arachnoid cysts associated with symptoms such as headache and abnormally enlarging head circumference; 2) progressively expanding arachnoid cysts; and 3) large arachnoid cysts such as Galassi Type III. A cyst fenestration was performed as a first-line treatment, and shunt placement was required if symptoms associated with increased ICP were found following fenestration. The risk factors evaluated included age, sex, presenting symptoms, the presence of head enlargement, progressive cyst expansion, and subdural hematoma/hygroma. RESULTS Four patients (15.4%) required shunt placement after cyst fenestration. Younger age, abnormal head enlargement, and progressive cyst expansion before fenestration were significantly associated with the need for shunt placement following fenestration. Arachnoid cysts decreased in size in 22 patients (84.6%) after fenestration and/or shunt placement. The presence of symptoms was not associated with postoperative cyst size in this study. CONCLUSIONS In this study, younger age, abnormal head enlargement, and progressive cyst expansion were risk factors for shunt placement after cyst fenestration in pediatric patients with middle cranial fossa arachnoid cysts. It is important to consider that cyst fenestration may not be effective because of a latent derangement of CSF circulation in patients with these risk factors.

123I-IMP-SPECT in a patient with cerebral proliferative angiopathy: a case report.

Cerebral proliferative angiopathy (CPA) is a new clinical entity demonstrating a diffuse network of densely enhanced vascular abnormalities with intermingled normal brain parenchyma and is distinguishable from classical arteriovenous malformations by specific clinical and imaging markers. However, the pathophysiological nature of this disease is unclear, and there is no consensus on the treatment. We describe cerebral perfusion abnormalities in a patient with CPA by using N-isopropyl-p-[123I] iodoamphetamine single-photon emission computed tomography (123I-IMP-SPECT) and perfusion-weighted magnetic resonance imaging. The patient, a 13-year-old boy, had reversible focal neurological deficits unrelated to cerebral hemorrhage. 123I-IMP-SPECT at resting state showed preserved uptake within the vascular lesion, yet lower uptake in the area adjacent to the lesion. In addition, acetazolamide-stressed 123I-IMP-SPECT exhibited severely impaired cerebrovascular reactivity over the affected hemisphere, suggesting that his focal neurological deficits were related to the cerebral ischemia. The perfusion abnormalities on 123I-IMP-SPECT in a CPA patient have never been previously reported. The concept of vascular malformation-related hypoperfusion is discussed.

Surgical treatment of scaphocephaly with sinus pericranii.

A 1-year-old female was admitted with a subcutaneous, pulsatile soft mass in the midline parietal region, and abnormal head shape. Fundus examination showed papilledema, suggesting elevated intracranial pressure. Radiological findings showed sagittal suture craniosynostosis with sinus pericranii. Magnetic resonance venography showed that the drainage through the sinus pericranii was not essential for the venous outflow from the brain. The patient underwent surgical resection of the sinus pericranii and total cranial remodeling. Ligation of the stalk-like orifice attached to the superior sagittal sinus with resection of the sinus pericranii and total cranial reconstruction were performed concurrently. The postoperative course was uneventful, and her papilledema resolved. No recurrence of the sinus pericranii has occurred for 3 years. This case describes a unique one-staged operation to treat sinus pericranii with sagittal suture craniosynostosis.

Surgical indication and outcome in patients with postoperative retethered cord syndrome.

OBJECT: After untethering of spinal dysraphism, some patients present with neurological deterioration, defined as retethered cord syndrome. It is known that surgical untethering is an option for improving the symptoms of retethered cord syndrome. Previous reports have shown that postoperative improvement in retethered cord syndrome was noted in the majority of patients presenting with pain, and in more patients with motor weakness than in those with urological symptoms. The authors speculate that subjective symptoms may be detected while symptoms are still reversible. In contrast, changes in urological function are less easy to diagnose, and delays in treatment may be complicated by advanced symptoms. In this study, patients with retethered cord syndrome were evaluated to investigate the benefits of performing routine urodynamic study to detect detrusor overactivity, which is considered to be a subclinical change of urological function, and to investigate the efficacy of early untethering surgery on the symptoms of retethered cord syndrome. METHODS: Surgical indications and outcomes of 78 untethering operations (20 for myelomeningocele, 58 for spinal lipoma) for retethered cord syndrome were examined. Diagnosis of retethered cord syndrome was defined by a multidisciplinary spina bifida team, and included routine urodynamic study. RESULTS: Preoperative symptoms included urological symptoms (70%), lower-extremity symptoms (45%), and others. The most frequent urological symptom was detrusor overactivity detected by urodynamic study (88.7%). Urinary incontinence was only found in 9.4% of patients. Postoperatively, progressive motor weakness improved in all patients, and sensory symptoms improved in 94%. Urological symptoms improved in 80% of the patients with urinary incontinence and in 75% of the patients with detrusor overactivity. Postoperative urodynamic study showed a significant increase in bladder volume (p < 0.05). The most common complication was temporary lower leg paresthesia that recovered at follow-up. Aggravated dysuria was noted in 3 patients. CONCLUSIONS: Early untethering operations offer symptomatic relief to patients with retethered cord syndrome. Urodynamic study findings, especially detrusor overactivity, are considered to be the most significant indicators for early diagnosis of retethered cord syndrome.

Efficacy of intraoperative irrigation with saline for preventing shunt infection.

OBJECT: The rate of infection following shunt procedures is unacceptably high. The authors have hypothesized that the key to reducing the shunt infection rate is in reducing bacteria in the operating field and wound. This hypothesis has been tested in a prospective nonrandomized controlled manner. METHODS: Data obtained in all patients undergoing shunt insertions or revisions for hydrocephalus performed between October 1, 2003, and June 12, 2009, were reviewed. Starting in August 2006, we began routinely irrigating the operating field and wound with saline solution from a syringe. Prior to this, we had not used any irrigation techniques, providing an adequate control group (Group A) for the effect of the irrigation technique. Prior to November 2007, we used saline containing amikacin for irrigation (Group B). After that date, we used saline only for irrigation (Group C). RESULTS: A total of 150 shunt procedures were performed in 79 girls and 71 boys during the study period. The mean age of all patients was 44.0 +/- 59.1 months. Groups A, B, and C comprised 61, 40, and 49 shunt procedures, respectively. There was no statistical difference in age among the 3 groups. Nine infections occurred within 90 days in the postoperative period. The overall infection rate was 6.0%. Eight infections occurred before introducing the irrigation procedure (infection rate 13.1%). One infection was noted after introducing irrigation (Group B [0.0%] + Group C [2.0%]; combined B and C infection rate = 1.1%). There was a statistical difference in the infection rate between Group A and Groups B and C combined (p = 0.003), Groups A and B (p = 0.021), and Groups A and C (p = 0.035). In contrast, no statistical difference was observed between Groups B and C (p > 0.99). Six of the 9 infections were due to staphylococcal species. CONCLUSIONS: An irrigation technique used to reduce bacteria in the operating field and wound is effective for preventing shunt infection. Irrigation alone, and not antibiotics, contributed to the prophylaxis of shunt infection.

Clock genes regulate neurogenic transcription factors, including NeuroD1, and the neuronal differentiation of adult neural stem/progenitor cells.

The circadian clock system plays multiple roles in our bodies, and clock genes are expressed in various brain regions, including the lateral subventricular zone (SVZ) where neural stem/progenitor cells (NSPCs) persist and postnatal neurogenesis continues. However, the functions of clock genes in adult NSPCs are not well understood. Here, we first investigated the expression patterns of Clock and Bmal1 in the SVZ by immunohistochemistry and then verified how the expression levels of 17 clock and clock-related genes changed during differentiation of cultured adult NSPCs using quantitative RT-PCR. Finally, we used RNAi to observe the effects of Clock and Bmal1 on neuronal differentiation. Our results revealed that Clock and Bmal1 were expressed in the SVZ and double-stained with the neural progenitor marker Nestin and neural stem marker GFAP. In cultured adult NSPCs, the clock genes changed their expression patterns during differentiation, and interestingly, Bmal1 started endogenous oscillation. Moreover, gene silencing of Clock or Bmal1 by RNAi decreased the percentages of neuronal marker Map2-positive cells and expression levels of NeuroD1 mRNA. These findings suggest that clock genes are involved in the neuronal differentiation of adult NSPCs and may extend our understanding of various neurological/psychological disorders linked to adult neurogenesis and circadian rhythm.

Hippocampal and thalamic diffusion abnormalities in children with temporal lobe epilepsy.

PURPOSE: Previous studies using diffusion MRI in patients with temporal lobe epilepsy have shown abnormal water diffusion in the hippocampus. Because thalamus and lentiform nuclei are considered important for the regulation of cortical excitability and seizure propagation, we analyzed diffusion tensor imaging (DTI) abnormalities in these subcortical structures and in hippocampus of children with partial epilepsy with and without secondary generalization. METHODS: Fourteen children with partial epilepsy involving the temporal lobe underwent MRI including a DTI sequence. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained in the hippocampus, thalamus, and lentiform nucleus, and compared with DTI data of 14 control children with no epilepsy, as well as glucose positron emission tomography (PET) findings. RESULTS: Decreased FA (p < 0.001) and increased ADC (p = 0.003) values were found in the hippocampi ipsilateral to the seizure focus. Significant FA decreases (p = 0.002) also were seen in the contralateral hippocampi, despite unilateral seizure onset and excellent surgical outcome in patients who underwent surgery. ADC values showed a trend for increase in the thalami ipsilateral to the epileptic focus in the seven children with secondarily generalized seizures (p = 0.09). No group differences of ADC or FA were found in the lentiform nuclei. The DTI variables did not correlate with regional glucose metabolism in any of the structures analyzed. CONCLUSIONS: Increased ADC values in hippocampus can assist in lateralizing the seizure focus, but decreased FA in the contralateral hippocampus suggests that it too may be dysfunctional despite unilateral seizure onset. Less-robust thalamic abnormalities of water diffusion in patients with secondarily generalized seizures suggest secondary involvement of the thalamus, perhaps due to recruitment of this structure into the epileptic network; however, this must be confirmed in a larger population. DTI appears to be a sensitive method for detection abnormalities in children with partial epilepsy, even in structures without apparent changes on conventional MRI.