CT Cisternography Research Articles

3D-CT Epidurography Can Detect Cerebrospinal-Fluid Leakage in a Patient with Spontaneous Intracranial Hypotension: A Case Report.

Spontaneous intracranial hypotension presents with many symptoms including orthostatic headache, dizziness, and nausea due to cerebrospinal-fluid (CSF) leakage from the spinal dural sac. Although CSF leakage can be estimated by radioisotope (RI) cisternography or computed tomography/magnetic resonance imaging myelography, it is not easy to detect the leakage point using these modalities. Here, we describe a patient with spontaneous intracranial hypotension in whom three-dimensional computed tomography (3D-CT) performed just after an epidural blood patch (EBP) containing contrast medium detected leakage point. The contrast medium injected into the epidural space at the L3/4 level migrated into the intradural space at the lower cervical spine level. RI cisternography performed before EBP did not show the CSF leakage point or any intracranial extension of the tracer. The rostral extension of the RI may be blocked by the collapse of the CSF space due to a large amount of CSF leakage, and due to the compression of the intradural CSF space by epidural CSF. 3D-CT epidurography may be useful to detect the fistula of a CSF leakage even in patients where other modalities including MRI, CT, or RI cisternography cannot specify the leakage point.

The results of the surgical treatment of spontaneous rhinorrhea via craniotomy and the contribution of CT cisternography to detection of exact leakage site of csf

To share the results of conventional surgery in rhinorrhea and the contribution of computerized tomography (CT) cisternography to determination of the site of cerebrospinal fluid (CSF) leak. Twelve cases treated for spontaneous rhinorrhea were included in this study. All the cases underwent cranial CT and magnetic resonance imaging (MRI). CT cisternography was performed in four patients whose bone defect or leakage site could not be detected by CT and MRI. In order to repair the defect, either the galea or galea together with collagen matrix was used and the procedure was supported with fibrin glue. In the cases, postoperative rhinorrhea was seen in neither the early nor the late follow up period. We observed no complications related to CT cisternography or craniotomy. The leakage area was successfully detected with CT cisternography when the other methods failed. Bone defect can usually be shown by means of CT. However, when bone-defect cannot be shown or the dura in the defective area is intact, CT cisternography is useful to show the CSF leak. Conventional surgery was very succesful in the treatment of spontaneous rhinorrhea but it was cosmetically problematic. In the patients both treated with galea and galea together with collagen matrix, the repair of the defect was successful.

Evaluation of posttraumatic recurrent bacterial meningitis in adults.

Acute bacterial meningitis may develop as a complication after head trauma. The aim of this study was to present the demographic, clinical, microbiological and radiological characteristics of adult patients who presented with recurrent bacterial meningitis attacks after trauma. Using a retrospective approach, the medical records of patients with acute recurrent bacterial meningitis (RBM) were reviewed, and those who had a history of trauma were included into the study. RBM was diagnosed based on clinical, bacteriologic and laboratory results. Demographic characteristics, clinical course, laboratory test results including cerebrospinal fluid analysis (CSF), radiological images, and the applied treatments were evaluated. A total of two hundred and twelve patients with acute bacterial meningitis were included into the study. RBM was diagnosed in twenty-five patients (11.8%), and in 18 of these patients (8.5%), the attacks had occurred subsequent to a trauma. In the CSF cultures of four patients, S. pneumoniae growth was observed. CT cisternography indicated CSF leaks in eleven patients. Moreover, bone fractures were observed in the CT images of ten patients. Ceftriaxone therapy was prescribed to 83% of the patients. Eight patients had a history of a fall in childhood, and five were involved in traffic accidents before acute bacterial meningitis. Four of the patients developed epilepsy and one developed deafness as sequelae. Since RBM attacks are frequently observed following trauma, in patients with a history of trauma who present with meningitis, the risk of recurrence should be considered.

3T MRI and 128‐slice dual‐source CT cisternography images of the cranial nerves a brief pictorial review for clinicians

There is a broad community of health sciences professionals interested in the anatomy of the cranial nerves (CNs): specialists in neurology, neurosurgery, radiology, otolaryngology, ophthalmology, maxillofacial surgery, radiation oncology, and emergency medicine, as well as other related fields. Advances in neuroimaging using high-resolution images from computed tomography (CT) and magnetic resonance (MR) have made highly-detailed visualization of brain structures possible, allowing normal findings to be routinely assessed and nervous system pathology to be detected. In this article we present an integrated perspective of the normal anatomy of the CNs established by radiologists and neurosurgeons in order to provide a practical imaging review, which combines 128-slice dual-source multiplanar images from CT cisternography and 3T MR curved reconstructed images. The information about the CNs includes their origin, course (with emphasis on the cisternal segments and location of the orifices at the skull base transmitting them), function, and a brief listing of the most common pathologies affecting them. The scope of the article is clinical anatomy; readers will find specialized texts presenting detailed information about particular topics. Our aim in this article is to provide a helpful reference for understanding the complex anatomy of the cranial nerves.

Endoscopic Management of Meningoencephaloceles and other Cranial Base Defects using Septal Cartilage

ABSTRACTObjectiveTo study and analyze 40 cases managed endoscopically of meningoencephaloceles and other cranial base defects using septal cartilage.DesignProspective, interventional case series.Materials and methodsThis study was conducted in the Department of Otorhinolaryngology SMS Medical College from 2006 to 2011. The study consisted of evaluations of self-reported and referred patients who presented to ENT OPD and emergency. In all the cases a detailed history and clinical examination was done. All the patients underwent nasal endoscopic examination. Computed tomographic (CT) scans were obtained for all cases. Magnetic resonance imaging (MRI) and CT cisternography was done in some of the cases.ResultsSuccess of the treatment was defined as resolution of symptoms, stoppage of leak, no recurrence, no complication and regular follow-up. A total of 40 cases were managed between 2006 and 2011 and were reviewed. The main presentation was of cerebrospinal fluid (CSF) leak in 22 cases with most common cause being traumatic. Fovea ethmoidalis being the most common site involved in 19 cases.ConclusionEndoscopic repair is the most modern and best result-oriented tool in the armamentarium of a surgeon to handle CSF leaks and with use of septal cartilage the results are less burdened with recurrences and failures.How to cite this articleMehta R, Sonkhya D, Sonkhya N . Endoscopic Management of Meningoencephaloceles and other Cranial Base Defects using Septal Cartilage. Clin Rhinol An Int J 2013;6(2):67-71.

Spontaneous cerebrospinal fluid rhinorrhoea: computed tomography and magnetic resonance imaging findings

Spontaneous cerebrospinal fluid rhinorrhoea is a rare clinical entity. The accurate localisation of the leakage site is essential for surgical planning. Imaging techniques such as high-resolution computed tomography (CT), CT cisternography and magnetic resonance cisternography in variable combinations are performed for this purpose. This pictorial essay aims to present the spectrum of imaging findings in cases of spontaneous cerebrospinal fluid rhinorrhoea, which may be useful for radiologists in the determination of the site of cerebrospinal fluid leakage.

Effect of Severity of Laryngopharyngeal Reflux Measured by Clinical Parameters on Laryngeal Mucin Gene Expression

Effect of Severity of Laryngopharyngeal Reflux Measured by Clinical Parameters on Laryngeal Mucin Gene Expression Background: Cerebrospinal fluid (CSF) fistulae that present as intermittent rhinorrhea can be a diagnostic challenge. Many imaging modalities are currently used for detection of a CSF fistula, including invasive techniques such as CT Cisternography and Radionuclide Cisternography. The purpose of this study is to present our experience with non-invasive imaging of intermittent CSF rhinorrhea. Methods: Retrospective chart review of New York University Medical Center patient database with suspected intermittent CSF rhinorrhea. Results: Nine patients were included in this study; a β2-transferrin assay was performed when possible. All patients had imaging that included High-Resolution CT (HRCT), MR Cisternography (MRC), or a combination of the two. When HRCT was combined with MRC the sensitivity and accuracy of detecting and localizing a CSF fistula were both 100%. Conclusion: Intermittent CSF rhinorrhea may be evaluated with HRCT and MR Cisternography, as these two modalities have good reliability and are non-invasive techniques.

Non-invasive Radiologic Evaluation of Intermittent CSF Rhinorrhea

Non-invasive Radiologic Evaluation of Intermittent CSF Rhinorrhea Background: Cerebrospinal fluid (CSF) fistulae that present as intermittent rhinorrhea can be a diagnostic challenge. Many imaging modalities are currently used for detection of a CSF fistula, including invasive techniques such as CT Cisternography and Radionuclide Cisternography. The purpose of this study is to present our experience with non-invasive imaging of intermittent CSF rhinorrhea. Methods: Retrospective chart review of New York University Medical Center patient database with suspected intermittent CSF rhinorrhea. Results: Nine patients were included in this study; a β2-transferrin assay was performed when possible. All patients had imaging that included High-Resolution CT (HRCT), MR Cisternography (MRC), or a combination of the two. When HRCT was combined with MRC the sensitivity and accuracy of detecting and localizing a CSF fistula were both 100%. Conclusion: Intermittent CSF rhinorrhea may be evaluated with HRCT and MR Cisternography, as these two modalities have good reliability and are non-invasive techniques.

The diagnosis and surgical treatment of occult otogenic CSF leakage

Conclusions: The diagnosis of occult otogenic cerebrospinal fluid (CSF) leakage is challenging and it can easily be misdiagnosed. Some characteristics of clinical presentation can supply important clues and confirmed diagnosis should be obtained according to these clues and suitable imaging studies before meningitis develops. Different surgical techniques should be adopted to treat the CSF leakage according to different leakage etiologies, and good results can be obtained. Objective: The aim of the study was to evaluate the diagnosis and surgical treatment of occult otogenic CSF leakage, including the characteristics of clinical presentation, imaging studies, and operation methods in order to decrease the rate of misdiagnosis and obtain a good curative effect. Methods: We performed a retrospective review of 11 cases of CSF leakage that were all misdiagnosed and accompanied by meningitis, operated in our department from 2007 to 2012 after a mean follow-up of 3 years. In this context, the characteristics of clinical presentation, imaging studies, and management of CSF leakage were studied. Results: The CSF leakage had arisen traumatically (n = 9) or congenitally (n = 2). The medical history and special clinical presentation such as repeated otorrhea or rhinorrhea, fever, headache, and unilateral deafness can supply important diagnostic clues. Imaging studies including high-resolution noncontrast CT (HRCT), CT cisternography, and magnetic resonance imaging (MRI) are very important diagnostic methods. The surgical repairs were performed via a transmastoid approach (n = 8), packing the vestibule (n = 1) or a translabyrithine approach (n = 2). Recurrent leakage did not occur.

CT cisternography in intracranial symptomatic arachnoid cysts: Classification and treatment

ObjectivesThe symptom and neuroimaging as indications for treating arachnoid cysts (ACs) are not adequate. Understanding the communication between cyst and subarachnoid space is helpful for decision-making. We took a dynamic study of ACs using CT cisternography (CTC) and proposed a classification of arachnoid cysts. Materials and methodsTotal 52 symptomatic patients with ACs were enrolled in this prospective study. CTC images were ordered, in all enrolled patients, at the 1, 3, 6, 12, 24 and 48h after the intrathecal Omnipaque administration. Enhancement in cysts was measured quantitatively and was compared with neighboring subarachnoid spaces. All enrolled patients were allocated randomly in 2 groups. The CTC result was considered before treatment in one group (CTC group), while another group was surgically treated without considering CTC results (surgical group). ResultsACs in our study were classified into 3 types: complete (cyst filling time at 1h), incomplete (filling time began at 3h) and noncommunicating cysts (no or slight filling after 24h). Twenty-two patients in CTC group with incomplete communicating, or noncommunicating cysts underwent surgeries. And other 6 patients with complete communicating cysts were closely observed. In CTC group, the symptom of all surgical patients was relieved, and 5 out of 6 observational patients showed clinical improvement or no deterioration during the follow-up. In surgical group, only 18 out of 24 patients showed clinical improvement after surgeries, and there were 6 patients showing no difference before and after surgeries in symptom and in imaging. ConclusionsThis classification based on dynamic CT cisternography is useful for the decision of surgical indication. Some symptomatic patients with complete communicating ACs may not need surgical intervention.

CT cisternography role in posttraumatic basal liquorrhea diagnostics

Введение. Посттравматическую базальную ликворею (ПБЛ) обнаруживают у 2-3% пострадавших при черепно-мозговой травме (ЧМТ). Частота возникновения менингита у пострадавших с посттравматическими ликворными фистулами (ПЛФ) составляет 3-50%. Точность КТ-цистернографии в диагностике ПБЛ от 22 до 100%. Методы. В целях определения эффективности КТ цистернографии в диагностике ПБЛ обследованы 29 больных. Эндолюмбально вводили контрастное вещество ультравист-240 из расчета 0,15 мл на 1 кг массы тела больного. Осуществляли сканирования во фронтальной плоскости от заднего края пирамиды височной кости до передней стенки лобной пазухи на 2-срезовом спиральном компьютерном томографе CTe-Dual (фирмы «General Electric», США). Результаты. Наличие менингоэнцефалоцеле и проникновение контрастированной спинномозговой жидкости за пределы субарахноидального пространства установлено при использовании метода КТ-цистернографии у 28 (96,6%) больных. У 25 больных обнаружена одна ПЛФ, в 4 - по две. Диагноз во всех наблюдениях подтвержден во время оперативного вмешательства. Выводы. КТ-цистернография - «золотой стандарт» в диагностике ПБЛ, в 96,6% наблюдений позволяет правильно установить локализацию и количество ПЛФ. Уточнение особенностей истечения спинномозговой жидкости позволяет провести КТ-цистернографию в момент лучшего контрастирования ПЛФ. Полная информация о ПЛФ обеспечивает правильное определение необходимого доступа, а также характер подхода к ней.

Spontaneous CSF Rhinorrhea Our Experience

To analyse the possible factors contributing to spontaneous cerebrospinal fluid (CSF) rhinorrhea and to assess the outcome of Transnasal endoscopic repair at our centre. Retrospective case series of patients with spontaneous CSF rhinorrhea at our institution from Jan 2006 to May 2010. 7 patients were diagnosed with spontaneous CSF rhinorrhea. 5 of the 7 patients were obese, middle aged females managed with Transnasal endoscopic repair with fascia lata auto graft. Successful repair of CSF rhinorrhea was achieved in all the patients with a single endoscopic procedure; no patient required a revision procedure. Spontaneous CSF rhinorrhea is a rare condition seen mostly in middle aged obese females with the anterior part of the cribriform plate being the most common site of leak. HRCT paranasal sinus (1mm cuts) was an effective modality of investigation in our study with ancillary investigations been CT Cisternography, CSF analysis and MRI for inactive leaks. In the absence of a large breech of the skull base, endoscopic repair of CSF rhinorrhea carries a high success rate with a high safety margin and very low morbidity rate.

Contrast ventriculo-cisternography: an auxiliary test for suspected fourth ventricular outlet obstruction

Fourth ventricular outlet obstruction (FVOO) causes obstructive hydrocephalus. Often, despite high-quality MRI sequences, differentiation between FVOO and communicating (absorptive) hydrocephalus is not easy. We describe our initial experience with five children with suspected FVOO that underwent CT ventriculography (CTV) or cisternography (CTC), to assist with this difficult diagnosis. Over 2.5 years, five children with suspected FVOO (5 months-7.5 years old) underwent CTV or CTC. Technical and clinical data were retrospectively collected. Four children had progressive macrocephaly, and one child had progressive ventriculomegaly. On CTV/CTC, four of five children showed communication between the ventricular system and spinal subarachnoid space or prepontine cistern, as evidenced by passage of contrast material. One child had a FVOO and therefore underwent an endoscopic third ventriculostomy, and is since, symptom and shunt free for 2.5 years. CT ventriculography in infants, and CT cisternography in elder children, may assist to differentiate between FVOO and communicating hydrocephalus. The importance of these tests is for children with MRI suggestive of FVOO related hydrocephalus, but with no clear demonstration of the obstruction site. The implication of this differentiation may be for deciding between treatment of hydrocephalus with a ventriculoperitoneal shunt or with an endoscopic third ventriculostomy.

Endoscopic fenestrations for suprasellar arachnoid cysts

The endoscopic treatment of a suprasellar arachnoid cyst (SAC) consists mainly of ventriculocystostomy (VC) and ventriculocystocisternostomy (VCC). However, the most appropriate treatment for these cysts has not been fully determined yet. The authors report on the effectiveness of endoscopic VC for SACs communicating with the basal cisterns, which is demonstrated by preoperative CT cisternography. The authors retrospectively analyzed the surgical results of patients with an SAC treated using endoscopic fenestration. The patient charts were reviewed for demographic data, clinical presentations, surgical therapies, and clinical outcomes. Six consecutive patients with SAC were surgically treated using endoscopic fenestration (VC or VCC) between March 2004 and February 2011. The mean age was 18.5 months (range 5 days to 37 months). Five patients were previously untreated, and 1 patient had previously undergone ventriculoperitoneal shunt placement. Five patients underwent preoperative CT cisternography, and communication between the SAC and the basal cisterns was demonstrated in 3 patients, very slight communication in 1, and no communication in 1. Four patients, including the 3 with communication between the SAC and basal cisterns, underwent VC. Two patients with very slight or no communication underwent VCC. In all patients the SAC decreased in size and hydrocephalus improved postoperatively. Five patients (3 treated with VC and 2 with VCC [83%]) have been stable without reoperation (mean follow-up 32.7 months). All 3 patients with an SAC communicating with the basal cisterns have been stable without reoperation following VC. Preoperative cisternography may be useful for selecting the optimal endoscopic treatment method for SAC. If an SAC communicates with the basal cisterns, a VC could be an effective, safe, and simpler treatment option.

小児神経疾患におけるMetrizamideの使用経験 脊髄腔造影, 脳室撮影, CT cisternography

小児神経疾患におけるMetrizamideの使用経験 脊髄腔造影, 脳室撮影, CT cisternography

Computed tomography-guided gamma knife stereotactic radiosurgery for trigeminal neuralgia

Gamma knife stereotactic radiosurgery (GKSR) is an effective minimally invasive option for the treatment of medically refractory trigeminal neuralgia (TN). Optimal targeting of the retrogasserian trigeminal nerve target requires thin-slice, high-definition stereotactic magnetic resonance imaging (MRI). The purpose of this study was to evaluate management outcomes in TN patients ineligible for MRI and who instead underwent GKSR using computed tomography (CT). The authors reviewed their experience with CT-guided GKSR in 21 patients (median age: 75 years) with idiopathic TN. Contraindications to MRI included implanted pacemakers (n = 16), aneurysm clips (n = 2), cochlea implants (n = 1), metallic vascular stents (n = 1) or severe obesity (weight of 163 kg, n = 1). Contrast-enhanced CT at 1- or 1.25-mm intervals was acquired in all patients. One patient also underwent CT cisternography. The median target dose for GKSR was 80 Gy. The median follow-up was 35 months after GKSR. Treatment outcomes were compared to 459 patients who underwent MRI-guided GKSR for TN at our institute in the same time interval. Targeting of the trigeminal nerve guided by CT scan was feasible in all patients. Stereotactic frame titanium pin-related artifacts that interfered with full visualization of the trigeminal nerve were found in one patient who had the ipsilateral posterior pin placed near the inion. After GKSR, 90% of patients achieved initial pain relief that was adequate or better, with or without medication (Barrow Neurological Institute pain scores I-IIIb). Median time to pain relief was 2.6 weeks. Pain relief was maintained in 81% at 1 year, 66% at 2 years, and 46% at 5 years. Eight (42%) of 19 patients who achieved initial pain relief reported some recurrent pain at a median of 18 months after GKSR. Some degree of facial sensory dysfunction occurred in 19% of patients within 24 months of GKSR. These results are comparable to those of patients who had MRI-guided GKSR. CT-guided GKSR provides a similar rate of pain relief as MRI-guided radiosurgery. The posterior pins should be placed at least 1 cm away from the inion to reduce pin and frame-related artifacts on the targeting CT scan. This study indicates that GKSR using CT targeting is appropriate for patients with medically refractory TN who are unsuitable for MRI.

Sternberg′s canal as a cause of encephalocele within the lateral recess of the sphenoid sinus: A report of two cases

Background:Intrasphenoidal encephaloceles are extremely rare findings. Sternberg's canal is a lateral craniopharyngeal canal resulting from incomplete fusion of the greater wings of the sphenoid bone with the basisphenoid. It acts as a weak spot of the skull base, which may lead to develop a temporal lobe encephalocele protruding into the lateral recess of the sphenoid sinus (SS).Case Description:We present two cases of intrasphenoidal encephalocele due to persistence of the lateral craniopharyngeal canal. The first case presented with cerebrospinal fluid (CSF) rhinorrhea and the second one was referred to the neurosurgical department with CSF rhinorrhea and meningitis. Radiological investigations consisted of computed tomography (CT) scan, CT cisternography and magnetic resonance images in both cases. These imaging studies identified a herniated temporal lobe through a bony defect which communicates the middle cranial fossa with the lateral recess of the SS. Both patients underwent a transcranial repair of the encephalocele because of the previous failure of the endoscopic surgery. There was no complication related to the surgical procedure and no recurrence of CSF leakage occurred 2 and 3 years after surgery, respectively.Conclusion:Encephalocele within the lateral recess of the SS is a rare entity which must be suspected in patients who present with spontaneous CSF rhinorrhea. Congenital intrasphenoidal encephaloceles, which are located medial to the foramen rotundum, seem to be due to persistence of the Sternberg's canal. Transcranial approach is a good option when a transnasal approach had failed previously.

A dosimetric comparison between Gamma Knife and CyberKnife treatment plans for trigeminal neuralgia

Object The Leksell Gamma Knife and the Accuray CyberKnife systems have been used in the radiosurgical treatment of trigeminal neuralgia. The 2 techniques use different delivery methods and different treatment parameters. In the past, CyberKnife treatments have been associated with an increased incidence of treatment-related complications, such as facial numbness. The goal of this study was to develop a method for planning a CyberKnife treatment for trigeminal neuralgia that would reproduce the dosimetric characteristics of a Gamma Knife plan. A comparison between Gamma Knife and CyberKnife treatment plans obtained with this method is presented. Methods Five patients treated using the Gamma Knife Perfexion Unit were selected for this study. All patients underwent CT cisternography to accurately identify the position of the trigeminal nerve. The Gamma Knife plans used either one 4-mm-diameter collimator or two coincident 4-mm collimators (one open and one with sector blocking) placed at identical isocenter coordinates. A maximum local dose of 80 Gy was prescribed. Critical structures and representative isodose lines were outlined in GammaPlan and exported to the CyberKnife treatment planning platform. CyberKnife treatments were developed using the 5-mm-diameter cone and the trigeminal node set, which provides an effective collimation diameter of 4 mm at the isocenter. The 60-Gy isodose volume imported from GammaPlan was used as the target in the CyberKnife plans. The CyberKnife treatments were optimized to achieve target dose and critical structure sparing similar to the Gamma Knife plans. Isocentric and nonisocentric delivery techniques were investigated. Treatment plans were compared in terms of dosimetric characteristics, delivery, and planning efficiency. Results CyberKnife treatments using the 5-mm cone and the trigeminal node set can closely reproduce the dose distribution of Gamma Knife plans. CyberKnife isocentric and nonisocentric plans provide comparable results. The average length of the trigeminal nerve receiving a dose of 60 Gy was 4.5, 4.5, and 4.4 mm for Gamma Knife, nonisocentric CyberKnife, and isocentric CyberKnife, respectively. However, minimizing the dose to the critical structures was more difficult with the CyberKnife and required the use of tuning structures. In addition, the dose falloff away from the target was steeper in Gamma Knife plans, probably due to the larger number of beams (192 beams for Perfexion vs ~ 100 beams for CyberKnife). While the treatment time with the CyberKnife is generally shorter, the planning time is significantly longer. Conclusions CyberKnife radiosurgical parameters can be optimized to mimic the dose distribution of Gamma Knife plans. However, Gamma Knife plans result in superior sparing of critical structures (brainstem, temporal lobe, and cranial nerves VII and VIII) and in steeper dose falloff away from the target. The clinical significance of these effects is unknown.

Cerebrospinal fluid dynamics between the basal cisterns and the subarachnoid space of the optic nerve in patients with papilloedema

AimsTo determine cerebrospinal fluid (CSF) dynamics between intracranial CSF spaces and CSF in the subarachnoid space (SAS) of optic nerves (ONs) in 10 patients with papilloedema.MethodsProspective assessment of 10 patients...

Editorial

The Leksell Gamma Knife and the Accuray CyberKnife systems have been used in the radio surgical treatment of trigeminal neuralgia. The 2 techniques use different delivery methods and different treatment parameters. In the past, CyberKnife treatments have been associated with an increased incidence of treatment-related complications, such as facial numbness. The goal of this study was to develop a method for planning a CyberKnife treatment for trigeminal neuralgia that would reproduce the dosimetric characteristics of a Gamma Knife plan. A comparison between Gamma Knife and CyberKnife treatment plans obtained with this method is presented.Five patients treated using the Gamma Knife Perfexion Unit were selected for this study. All patients underwent CT cisternography to accurately identify the position of the trigeminal nerve. The Gamma Knife plans used either one 4-mm-diameter collimator or two coincident 4-mm collimators (one open and one with sector blocking) placed at identical isocenter coordinates. A maximum local dose of 80 Gy was prescribed. Critical structures and representative isodose lines were outlined in GammaPlan and exported to the CyberKnife treatment planning platform. CyberKnife treatments were developed using the 5-mm-diameter cone and the trigeminal node set, which provides an effective collimation diameter of 4 mm at the isocenter. The 60-Gy isodose volume imported from GammaPlan was used as the target in the CyberKnife plans. The CyberKnife treatments were optimized to achieve target dose and critical structure sparing similar to the Gamma Knife plans. Isocentric and nonisocentric delivery techniques were investigated. Treatment plans were compared in terms of dosimetric characteristics, delivery, and planning efficiency.CyberKnife treatments using the 5-mm cone and the trigeminal node set can closely reproduce the dose distribution of Gamma Knife plans. CyberKnife isocentric and nonisocentric plans provide comparable results. The average length of the trigeminal nerve receiving a dose of 60 Gy was 4.5, 4.5, and 4.4 mm for Gamma Knife, nonisocentric CyberKnife, and isocentric CyberKnife, respectively. However, minimizing the dose to the critical structures was more difficult with the CyberKnife and required the use of tuning structures. In addition, the dose fall off away from the target was steeper in Gamma Knife plans, probably due to the larger number of beams (192 beams for perfexion vs ~ 100 beams for cyberknife). While the treatment time with the cyberknife is generally shorter, the planning time is significantly longer.CyberKnife radiosurgical parameters can be optimized to mimic the dose distribution of Gamma Knife plans. However, Gamma Knife plans result in superior sparing of critical structures (brainstem, temporal lobe,and cranial nerves VII and VIII) and in steeper dose fall off away from the target. The clinical significance of these effects is unknown. (DOI: 10.3171/2010.8.GKS101002)