Chiasmal Glioma Research Articles

LGG-04. TRAMETINIB COMBINED WITH CHEMOTHERAPY FOR INFANT BRAF-FUSED CHIASMATIC GLIOMA

Abstract BACKGROUND Infant chiasmatic gliomas present a major therapeutic challenge due to large size, threat to vision and progressive nature. Infants <1 year respond poorly to Vincristine/Carboplatinum chemotherapy (SIOP-LGG2). BRAF fusion is common, so MEK inhibitors have been used second line in older children, but time to response is slow (median ~20 months). Data on the use of these drugs in infants is limited as is data on the safety and efficacy of combining chemotherapy with MEK inhibitors. METHODS We report two infants treated successfully for BRAF fused chiasmatic glioma - both presented age 5 months with nystagmus and diencephalic syndrome. Both had significant tumor progression within 6 weeks of starting Vincristine/ Carboplatin which responded rapidly to the addition of Trametinib. RESULTS Case 1 required tumor debulking at week 6 of chemotherapy due to progressive hyponatremia, hydrocephalus and brainstem compression. Surgery caused diabetes insipidus, hemianopia and hemiparesis. Tumor growth continued despite reinstating chemotherapy. Addition of trametinib caused tumor shrinkage by 75% within 12 weeks and 90% by 1 year. Minirin doses were reduced by 80% on Trametinib. After 1.3 years, chemotherapy was stopped & Trametinib continued alone. Case 2 - tumor growth and severe hyponatremia by week 6 of chemotherapy prompted addition of Trametinib without surgery. There was tumor reduction of 50% over 6 months and improvement of severe failure to thrive. Hyponatremia, requiring sodium and urea supplementation, stabilized. Bilateral vision and age-appropriate development are maintained. Hypertension developed early, but resolved completely after stopping and then gradually reintroducing Trametinib. Recurrent diarrhea required dose reduction. CONCLUSIONS We show the safety and efficacy of combined treatment with chemotherapy and MEK inhibition in infants and postulate that both the combination and the young age at initiation of therapy may have contributed to the excellent outcome. We urge for clinical trials of combination therapy in this age group.

Comparison of MRI findings of hypothalamic-optic chiasmatic gliomas and craniopharyngiomas.

Differential diagnosis of hypothalamic-optic chiasmatic gliomas (HOCGs) and craniopharyngiomas on magnetic resonance imaging (MRI) can be quite challenging. To compare the MRI features of HOCGs and cranipharyngiomas. Patients diagnosed with HOCG or craniopharyngioma in histopathological evaluation between 2012 and 2022 and who underwent preoperative contrast-enhanced brain MRI were included. Various MRI features were retrospectively evaluated for each lesion: T2-weighted imaging and fluid attenuation inversion recovery hyperintensity, calcification, cystic change, T1-weighted (T1W) imaging hyperintensity of the cystic component, hemorrhage, involvement of sellar, suprasellar or other adjacent structures, lobulated appearance, presence of hydrocephalus, and contrast enhancement pattern. Apparent diffusion coefficient (ADC) values were also evaluated and compared. Among 38 patients included, 13 (34%) had HOCG and 25 (66%) had craniopharyngioma. Craniopharyngiomas had a significantly higher rate of cystic changes, calcification, and T1W imaging hyperintensity of the cystic component than HOCGs (P <0.05). Of HOCGs, 92% had chiasm involvement, 23% had optic nerve involvement, and 31% had brain stem involvement. On the other hand, chiasm involvement was observed in 8% of craniopharyngiomas, but none had optic nerve and/or brain stem involvement (P <0.05). While 62% (8/13) of HOCGs had diffuse homogeneous enhancement, 80% (20/25) of craniopharyngiomas had a diffuse heterogeneous enhancement pattern. Mean ADC values were significantly higher in craniopharyngiomas compared to HOCGs (2.1 vs. 1.6 ×10-3mm2/s, P <0.05). Although some neuroimaging findings may overlap, features such as presence of cyst and calcification, brain stem and optic pathway involvement, different enhancement patterns, and ADC values may be helpful in the differential diagnosis of HOCGs and craniopharyngiomas.

Chiasm gliomas in pediatric patients. Part 1. Сlinical manifestations

Chiasm gliomas are very important heterogeneous group of tumors manifesting in the first and second decades of life and is the second leading cause of blindness in children with neurosurgical pathology. It is a benign, slow-growing piloid astrocytoma, accounting for 1–5% of intracranial gliomas in children. The incidence of neurofibromatosis type 1 among patients with chiasm glioma ranges from 7 to 60%. The location of the tumor is determined based on ophthalmological symptoms, neuroimaging data (MRI), and surgical findings. The initial growth of the tumor occurs in the anterior visual pathway structures (optic nerves, chiasm, optic tracts) and leads to ophthalmological symptoms, which are dominant in the clinical manifestations of the disease. Chiasm damage may occur in one or both optic nerves, in one or both optic tracts. Damage to the chiasm manifests as bitemporal heteronymous hemianopsia. Moreover, the spread of the tumor to the optic nerves is accompanied by decreased visual acuity. Damage to the optic tract is manifested by homonymous hemianopia and normal visual acuity. However, isolated damage to the optic tract is uncommon and usually occurs with chiasm and optic nerve lesions; hence, visual disturbances are more complex. Lesions in the optic nerve fibers in the chiasm and optic nerves/tracts lead to primary descending atrophy of the optic nerves. Papilledema with optic nerve atrophy indicates occlusive hydrocephalus. Delayed diagnosis of the disease affects treatment results.

Chiasmatic gliomas with diencephalic syndrome in infants: challenges in the diagnosis and treatment

Chiasmatic gliomas with diencephalic syndrome in infants: challenges in the diagnosis and treatment

Рідкісний випадок гліоми хіазми у жінки, хворої на гіпогонадотропний гіпогонадизм і ожиріння

Пухлина хіазми — рідкісне захворювання, що характеризується зниженням полів зору. Описаний випадок із практики пухлини хіазми із супутнім гіпогонадизмом і ожирінням. Встановлено, що репродуктивна функція у пацієнтки віком 25 років з пухлиною хіазми порушена внаслідок супутнього гіпоталамо-гіпофізарного захворювання, що спричинило розвиток гіпогонадотропного гіпогонадизму, центрального нецукрового діабету, дефіциту соматотропного гормону (пангіпопітуїтаризм).

Homonymous Retinal Ganglion Cell Layer Atrophy With Asymptomatic Optic Tract Glioma in Neurofibromatosis Type I

Approximately 20% of patients with Neurofibromatosis type 1 (NF1) develop optic pathway gliomas (OPGs). Not all OPGs in NF1 necessarily become vision compromising and predicting which patients might develop visual decline is difficult at present time. Optical coherence tomography (OCT) has emerged as a useful tool able to directly assess the morphology and thickness of individual retinal layers. The ganglion cell layer (GCL) is composed of the retinal ganglion cells which receive information from photoreceptors via interneurons, while the retinal nerve fiber layer (RNFL) contains the retinal ganglion cell unmyelinated axons that merge to form the optic nerve. Lesions of the anterior visual pathway result in retrograde axonal degeneration from ganglion cell death and ultimately manifest as thinning of the RNFL and/or GCL. In this report we highlight a case of a 38 year-old woman with an NF1 associated left chiasmal and optic tract glioma who had normal visual fields and visual acuity. However, using OCT we demonstrate a homonymous pattern of GCL atrophy that corresponds with her left optic tract glioma. Given this homonymous pattern of atrophy in the GCL and the left optic tract lesion, one would expect a right homonymous hemianopia. To our knowledge this is the first reported case of a homonymous pattern of GCL-IPL atrophy in an adult with an NF1 related OPG involving the optic chiasm and optic tract, but without objective visual field or acuity deficits. This case is important because, mechanistically, it suggests that a necessary threshold of GCL atrophy may be needed before visual concerns can be detected and, secondly, it invites future studies to evaluate whether OCT may serve as a potential screening tool for those with NF1 related OPGs.

Radiation-induced meningiomas: analysis of 33 cases

Development of meningiomas correlating with irradiation has been described in the last century. Different biological features of radiation-induced meningiomas depending on dose and type of irradiation have been observed in recent years. There were 8848 patients (women - 74.3%) with intracranial meningiomas for the period from 2000 to 2014 who underwent surgery at the Burdenko Neurosurgical Center. Radiation-induced meningiomas were identified in 33 patients (13 (38%) men and 20 (62%) women) aged 16-76 years (median 56 years). Medical data were retrospectively analyzed. Follow-up period ranged from 5 to 22 years (median 12) after verification of histological diagnosis. Meningiomas were preceded by X-ray irradiation of the scalp for ringworm (microsporia or trichophytosis) in 26 cases (79%) (group A). Group B enrolled 7 (21%) patients after previous radiotherapy for other tumors (retinoblastoma, chiasmal glioma, pituitary adenoma, basalioma). Data were compared using Mann-Whitney and Fisher's exact tests. Incidence of radiation-induced meningiomas was 0.37% in our sample. Meningioma diagnosis dates after X-ray epilation (median 52 years) significantly differed from that after radiotherapy (median 22 years) (Mann-Whitney test, p=0.0003). Primary multiple meningiomas were diagnosed only in the 1st group (Fisher's exact test, p=0.0005). Recurrent meningiomas after the first surgery were more common in the first group (58%) compared to the second one (14%) (Mann-Whitney test, p=0.0003). The latency period is shorter after radiotherapy (median 22 years compared to 52 years after X-ray epilation). Incidence of atypical and malignant meningiomas directly correlates with irradiation dose. Approximately equal incidence of radiation-induced meningiomas after X-ray epilation in women and men can indicate other mechanisms of development of these tumors in comparison with spontaneous ones. Radiotherapy is followed by occurrence of meningiomas within the irradiated area. These tumors are usually single. In case of X-ray epilation, the tumors may be localized anywhere within the intracranial space (convexital and/or parasagittal localization in 77% of cases). Multiple neoplasms occur in 42% of cases. Refusal of head X-ray epilation for the treatment of a ringworm for the last 50 years may be followed by reduced incidence of radiation-induced meningiomas, especially multiple ones. However, extended indications for radiotherapy of various brain diseases can result an increase of the incidence of meningiomas within the irradiated area.

Visual Function, Brain Imaging, and Physiological Factors in Children With Asymmetric Nystagmus due to Chiasmal Gliomas

PurposeAsymmetric nystagmus can be an important presenting sign of optic pathway gliomas in young children. We investigated the causes of asymmetric nystagmus in children with chiasmal or suprasellar optic pathway gliomas compared with children with similar optic pathway gliomas and stable gaze. MethodsLongitudinal magnetic resonance imaging before and after treatment, age-corrected visual acuity, ocular examinations, video-oculography, visual evoked potentials, and retinal nerve fiber layer thickness were retrospectively reviewed. ResultsTwenty-two children were included (eight with asymmetric nystagmus and 14 with stable gaze). Subjects with asymmetric nystagmus presented at a younger age than those with stable gaze (2.0 vs 5.6 years; P < 0.001). None had neurofibromatosis type 1. Visual acuity, visual evoked potentials, nerve fiber layer, severity of optic atrophy, hydrocephalus, tumor volume, and tumor locations did not differ between those with asymmetric nystagmus and stable gaze. Asymmetric nystagmus resolved shortly after treatment, even though the average visual acuity did not improve. Changes in visual acuity or tumor volume were not different between those with asymmetric nystagmus and stable gaze after treatment. Eye movement recording from two subjects with asymmetric nystagmus revealed an asymmetric pendular-oscillation with vertical components. One subject with stable gaze developed asymmetric nystagmus with tumor growth into the rostral midbrain and associated unilateral vision loss. Another subject with tumor growth into the rostral midbrain acquired vertical saccade dysmetria. ConclusionWe hypothesize that asymmetric nystagmus associated with optic pathway gliomas is caused by subclinical abnormalities to retinal axons that connect to gaze holding centers in the rostral midbrain. Direct compression of the rostral midbrain was a possible factor to asymmetric nystagmus in some subjects. However, many subjects with stable gaze also show midbrain compression.

Current and emerging treatment strategies for children with progressive chiasmatic-hypothalamic glioma diagnosed as infants: a web-based survey

Treatment of infant hypothalamic chiasmatic glioma (iCHG) is challenging, about 30% of the children progress during chemotherapy. Despite subsequent treatments the 5 year overall-survival rate is only 70%. This study investigates treatment strategies currently applied for progressive iCHG. A web-based questionnaire was sent out to the members of the SIOPE Brain Tumour Group asking for current second and third line strategies at progression during and after the end of first line therapy. The questionnaire was answered by 47 paediatric oncologists from 15 countries. iCHG progressing during first line therapy with carboplatin-vincristine would be considered for treatment with alternative chemotherapy by 17 (36%) and with surgery plus chemotherapy by 27 respondents (58%). Components suggested for second line were vinblastine (62%), cisplatin (34%) and cyclophosphamide (26%). For third line therapy bevacizumab (BVZ) was considered as suitable by respondents in 53% (often with irinotecan 40%) and vinblastine by 34% respectively. Experience with BVZ in CHG is shown by 53% of respondents regarding at least 95 patients (median treated 1–5 patients per respondent at any age) with a median BVZ administration over 12 months. Effectiveness was reported varying between stable disease and regression while complications were rarely stated (proteinuria, hypertension, bleeding). BVZ would be available to 85% of respondents as therapeutic option for iCHG patients. Multiple anti-neoplastic drug regimens are applied for progressive iCHG, partly considered in combination with surgery if safely feasible. BVZ is commonly used at a satisfactory level in third line, mainly combined with irinotecan.

Pediatric Suprasellar Tumors.

The various childhood suprasellar tumors, while pathologically distinct, present similar clinical and surgical challenges as a result of their common anatomic location. These lesions are in close proximity to or may invade the optic nerve and chiasm, pituitary gland and infundibulum, hypothalamus, and third ventricle, leading to presenting features including visual field loss, impairment in visual acuity, endocrine dysfunction, and hydrocephalus. Though many suprasellar lesions are relatively benign in pathology, treatment may be complicated by high surgical morbidity resulting from damage to the hypothalamic-pituitary axis. Here we review the most frequent pediatric lesions occurring in the suprasellar region: craniopharyngioma, chiasmatic glioma, germ cell tumor, Rathke cleft and arachnoid cysts, pituitary adenoma, and histiocytosis. This review outlines both common presenting features and differentiating aspects of these lesions. It also includes classic radiographic presentations and treatment considerations for each lesion.

Glioblastoma multiforme of the optic chiasm: A rare case of common pathology.

Background:Malignant optic and chiasmatic gliomas are extremely rare, and are classified pathologically as anaplastic astrocytoma or glioblastoma multiforme (GBM). Approximately 40 cases of optic GBM in adults have been reported in the literature, and only five of them were described to originate from the optic chiasm.Case Description:An 82-year-old male patient with a past medical history of diabetes mellitus type 2, melanoma, and bladder cancer presented with gradual vision loss of the left eye in a period of 1 month. After neuro-ophthalmological examination, the decision of thither magnetic resonance imaging (MRI) studies was made. It showed a contrast enhancing mass in the region of the optic chiasm. In this case, imaging study was not enough to establish an accurate diagnosis and a left pterional craniotomy for biopsy and resection of the optic chiasmal mass was performed. After histological evaluation of the mass tissue, the diagnosis of GBM was made. Taking into account the patient's poor condition and unfavorable prognosis he was moved to inpatient hospice. The patient deceased within 2 months after surgery.Conclusion:Chiasmal GBM is an extremely rare condition where a biopsy is necessary for accurate diagnosis and optimal treatment. Differential diagnosis for such lesions can be very difficult and include demyelinating optic neuritis and non-demyelinating inflammatory optic neuropathy (e.g., sarcoid), vascular lesions (e.g., cavernoma), compressive lesions of the optic apparatus, metastatic malignancy, and primary tumors of the anterior optic pathway. The role of chemotherapy and radiotherapy including novel stereotaxic radiosurgery methods is still unclear and will need to be evaluated.

QOL-15QUALITY OF LIFE IN MASSIVE OPTICOHYPOTHALAMIC GLIOMA. AN ANALYSIS OF AN EXPERIENCE IN 73 CASES TREATED OVER 18 YEARS

BACKGROUND: Visual pathway gliomas represent 1% to 5% of childhood brain tumors. About 43% occur in children <10 years old. Although benign, opticohypothalamic chiasmatic gliomas can have aggressive course in young children. PATIENTS AND METHODS: Seventy-three cases of opticohypothalamic chiasmatic were surgically treated in our department over the past 18 years (1990-2011). A retrospective analysis is presented. A semi-structured interview for disease domain specific quality of life (QOL) was performed in a focused group of 30 patients to elicit themes to provide a thematic analysis. RESULTS: The average age of presentation was 14.8 years and duration of complaints was 3 months. Headaches, vomiting and dimunition of vision were the most common complaints. The average size of the tumor was 7.4 cm. All patients underwent only biopsy of the tumor. The subfrontal approach was used in all patients. Ventriculoperitoneal shunt was required in 19 patients postoperatively. The average follow-up period was 7 years. Nonsymptomatic recurrence was noted in 8 patients. Overall, the median time to tumor progression was 55 months. The 5- and 10-year survival probabilities were 93 and 74%, respectively. The functional activity assessed by Barthel's Index is maintained in children with low grade optochiasmal gliomas treated with conformal RT. The decline in functional activity is seen in patients with tumor recurrence and in complications. However, there was improvement of functional activity after RT due to tumour control and rehabilitative support. The maximum improvement was seen in visually impaired patients. CONCLUSION: Barthel's Index is a simple, reproducible, quick and easy to perform. It is especially applicable for older children and adolescents and may be used as an outcome measure tool in clinics with resource limitations. The approach towards quality of life issues should be more aggressive including psychosocial intergration. There is a need for more objective and better quality of life studies.

Acquired nystagmus as the initial presenting sign of chiasmal glioma in young children.

The aim of the study was to investigate the incidence of nystagmus at diagnosis in children with optic pathway glioma involving the chiasm and hypothalamus. Twenty-two patients with a measurable optic pathway/hypothalamic glioma (without neurofibromatosis-1) were followed in our center from 2001 to 2013. The medical files were retrospectively reviewed for demographic and clinical findings, and the imaging scans, for tumor characteristics. There were 9 boys and 13 girls of mean age 3.5±4.4years at diagnosis; 15 were aged <2 years. Tumor size ranged from 10×6mm to 62×29mm. Mean duration of follow-up was 8.3±5.4 years. Nystagmus was detected at diagnosis in 10 children (45%), all <2 years old (66.6% of the younger group); no child older than 2 years presented with nystagmus. Nystagmus, once present, did not resolve and continued throughout follow-up. There were no cases of new onset of nystagmus during follow-up in the children in whom it was not detected at diagnosis. Treatment consisted of partial resection/biopsy with/without shunting (n=13) and chemotherapy (n=19) with (n=2) or without adjuvant radiation. Of the 22 children, 6 had a radiographic response to treatment, 8 remained stable, and 8 (all of whom received chemotherapy) showed disease progression despite treatment. In conclusion, monocular nystagmus is a more common presenting sign of optic pathway/hypothalamic glioma in children <2 years old than previously estimated. Although subtle, nystagmus has a very narrow differential diagnosis, and its presence should raise suspicions of a chiasmal tumor with prompt referral for imaging. The visual prognosis is moderate to poor.

Chiasmal Glioma in Spasmus Nutans

: We diagnosed chiasmal glioma in an 8-month-old infant who had spasmus nutans that spontaneously resolved. Magnetic resonance imaging showed no interval change in tumor size over the next 8 months. Clinical resolution of spasmus nutans does not preclude chiasmal glioma as the underlying cause.

The optic pathways gliomas in children with neurofibromatosis 1

Optic pathways gliomas have the maximal clinical expression in childhood around the age of 5, being the second tumor in neurofibromatosis type 1 in frequency. Considering their location, it describes three types of optic pathways gliomas: type I - retrobulbar gliomas, type II - optic tracts gliomas and type III - chiasmatic gliomas. Neuroimaging exams are essential in diagnosis and selection surgical patients. Management of these tumors is often difficult even they exhibit histological benign features. Patients harboring optic nerve gliomas with symptomatic and documented neuroimaging progression have indication of tumor resection. Optic nerve gliomas associated with neurofibromatosis type 1 have generally a good prognosis. Unfavorable prognostic factors are represented by the early clinical onset under 6 years of age and chiasmatic and retrochiasmatic location.

Hourly oral sodium chloride for the rapid and predictable treatment of hyponatremia

Hypertonic NaCl is first-line therapy for acute, severe and symptomatic hyponatremia; however, its use is often restricted to the intensive care unit (ICU). A 35-year-old female inpatient with an optic chiasm glioma and ventriculoperitoneal shunt for hydrocephalus developed acute hyponatremia (sodium 122 mEq/L) perhaps coinciding with haloperidol treatment. The sum of her urinary sodium and potassium concentrations was markedly hypertonic vis-à-vis plasma; it was inferred that serum sodium concentration would continue to fall even in the complete absence of fluid intake. Intravenous (IV) 3% NaCl was recommended; however, a city-wide public health emergency precluded her transfer to the ICU. She was treated with hourly oral NaCl tablets in a dose calculated to deliver the equivalent of 0.5 mL/kg/h of 3% NaCl with an objective of increasing the serum sodium concentration by 6 mEq/L. She experienced a graded and predictable increase in serum sodium concentration. A slight overshoot to 129 mEq/L was rapidly corrected with 0.25 l of D5W, and she stabilized at 127 mEq/L. We conclude that hourly oral NaCl, in conjunction with careful monitoring of the serum sodium concentration, may provide an attractive alternative to IV 3% NaCl for selected patients with severe hyponatremia.

Paediatric brain tumours—when to operate?

Surgical intervention in children with hypothalamic chiasmatic low-grade glioma, diffuse intrinsic pontine glioma, or high-grade glioma is controversial, and randomized controlled trials are lacking. A recent consensus statement provides recommendations for optimal management of these patients, including situations in which surgical resection represents the preferred option.

A multi-disciplinary consensus statement concerning surgical approaches to low-grade, high-grade astrocytomas and diffuse intrinsic pontine gliomas in childhood (CPN Paris 2011) using the Delphi method

Astrocytic tumors account for 42% of childhood brain tumors, arising in all anatomical regions and associated with neurofibromatosis type 1 (NF1) in 15%. Anatomical site determines the degree and risk of resectability; the more complete resection, the better the survival rates. New biological markers and modern radiotherapy techniques are altering the risk assessments of clinical decisions for tumor resection and biopsy. The increasingly distinct pediatric neuro-oncology multidisciplinary team (PNMDT) is developing a distinct evidence base. A multidisciplinary consensus conference on pediatric neurosurgery was held in February 2011, where 92 invited participants reviewed evidence for clinical management of hypothalamic chiasmatic glioma (HCLGG), diffuse intrinsic pontine glioma (DIPG), and high-grade glioma (HGG). Twenty-seven statements were drafted and subjected to online Delphi consensus voting by participants, seeking >70% agreement from >60% of respondents; where <70% consensus occurred, the statement was modified and resubmitted for voting. Twenty-seven statements meeting consensus criteria are reported. For HCLGG, statements describing overall therapeutic purposeand indications for biopsy, observation, or treatment aimed at limiting the risk of visual damage and the need for on-going clinical trials were made. Primary surgical resection was not recommended. For DIPG, biopsy was recommended to ascertain biological characteristics to enhance understanding and targeting of treatments, especially in clinical trials. For HGG, biopsy is essential, the World Health Organization classification was recommended; selection of surgical strategy to achieve gross total resection in a single or multistep process should be discussed with the PNMDT and integrated with trials based drug strategies for adjuvant therapies.

Pituicytoma: Report of three cases with review of literature

Pituicytoma is a rare low-grade tumor (WHO Grade I) of pituicytes involving the sellar–suprasellar region, and originating from the specialized glial cells of the neurohypophysis. Clinically and radiologically, they closely mimic pituitary adenoma or meningioma. Diagnosis requires histopathological examination of the resected tissue. This uncommon glial neoplasm is a rarity, with only 57 cases reported in the literature so far. We report three cases of pituicytoma (aged between 7 and 24 years) presenting with reduced vision, headache and features of hypercortisolism in one case. Radiologically, these lesions mimicked meningioma, hypothalamic chiasmatic glioma and pituitary microadenoma, respectively. The second case is a 7-year-old girl, the youngest case on record. Since this tumor is uncommon, it is frequently misdiagnosed. Awareness of this entity is essential for planning management and treatment. We present a brief review of all cases reported in the medical literature, and describe the clinical symptomatology, associated endocrinological abnormalities, imaging characteristics, behavior and outcome.

Magnetic resonance diffusion tensor imaging (MRDTI) of the optic nerve and optic radiations at 3T in children with neurofibromatosis type I (NF-1)

Optic pathway glioma (OPG) is a characteristic hallmark of neurofibromatosis type I (NF-I). To evaluate the feasibility of magnetic resonance diffusion tensor imaging (MRDTI) at 3T to detect abnormalities of the optic nerves and optic radiations in children with NF-I. 3-T MRDTI was prospectively performed in 9 children with NF-I (7 boys, 2 girls, average age 7.8years, range 3-17years) and 44 controls (25 boys, 19 girls, average age 8.1years, range 3-17years). Fractional anisotropy (FA) and mean diffusivity were determined by region-of-interest analysis for the optic nerves and radiations. Statistical analysis compared controls to NF-I patients. Two NF-I patients had bilateral optic nerve gliomas, three had chiasmatic gliomas and four had unidentified neurofibromatosis objects (UNOs) along the optic nerve pathways. All NF-I patients had statistically significant decreases in FA and elevations in mean diffusivity in the optic nerves and radiations compared to age-matched controls. MRDTI can evaluate the optic pathways in children with NF-I. Statistically significant abnormalities were detected in the diffusion tensor metrics of the optic nerves and radiations in children with NF-I compared to age-matched controls.