bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analyzing 3-tesla magnetic resonance imaging units for implementation in radiosurgery
Authors: Mack Andreas , Wolff Robert , Scheib Stefan , Rieker Marcus , Weltz Dirk , Mack G. , Kreiner Hans-Jürg , Pilatus Ulrich , Zanella Friedhelm E. , Böttcher Heinz D. , Seifert Volker 
Published: May 2009

Object.The limiting factor affecting accuracy during gamma knife surgery is image quality. The new generation of magnetic resonance (MR) imaging units with field strength up to 3 teslas promise superior image quality for anatomical resolution and contrast. There are, however, questions about chemical shifts or susceptibility effects, which are the subject of this paper.Methods.The 3-tesla MR imaging unit (Siemens Trio) was analyzed and compared with a 1-tesla unit (Siemens Magnetom Expert) and to a 1.5-tesla unit (Philips Gyroscan). Evaluation of the magnitude of error was performed within transverse slices in two orientations (axial/coronal) by using a cylindrical phantom with an embedded grid. Deviations were determined for 21 targets in a slab phantom with known geometrical positions within the stereotactic frame. Distortions caused by chemical shift and/or susceptibility effects were analyzed in a head phantom. Inhouse software was used for data analyses.The mean deviation was less than 0.3 mm in axial and less than 0.4 mm in coronal orientations. For the known targets the maximum deviation was 1.16 mm. By optimizing these parameters in the protocol these inaccuracies could be reduced to less than 1.1 mm. Due to inhomogeneities a shift in the z direction of up to 1.5 mm was observed for a dataset, which was shown to be compressed by 1.2 mm.Conclusions.The 3-tesla imaging unit showed superior anatomical contrast and resolution in comparison with the established 1-tesla and 1.5-tesla units; however, due to the high field strength the field within the head coil is very sensitive to inhomogeneities and therefore 3-tesla imaging data will have be handled with care.
Does gamma knife surgery stimulate cellular immune response to metastatic brain tumors? A histopathological and immunohistochemical study
Authors: Szeifert György T. , Salmon Isabelle , Rorive Sandrine , Massager Nicolas , Devriendt Daniel , Simon Stephan , Brotchi Jacques , Levivier Marc 
Published: May 2009

Object.The aim of this study was to analyze the cellular immune response and histopathological changes in secondary brain tumors after gamma knife surgery (GKS).Methods.Two hundred ten patients with cerebral metastases underwent GKS. Seven patients underwent subsequent craniotomy for tumor removal between 1 and 33 months after GKS. Four of these patients had one tumor, two patients had two tumors, and one patient had three. Histological and immunohistochemical investigations were performed. In addition to routine H & E and Mallory trichrome staining, immunohistochemical reactions were conducted to characterize the phenotypic nature of the cell population contributing to the tissue immune response to neoplastic deposits after radiosurgery.Light microscopy revealed an intensive lymphocytic infiltration in the parenchyma and stroma of tumor samples obtained in patients in whom surgery was performed over 6 months after GKS. Contrary to this, extensive areas of tissue necrosis with either an absent or scanty lymphoid population were observed in the poorly controlled neoplastic specimens obtained in cases in which surgery was undertaken in patients less than 6 months after GKS. Immunohistochemical characterization demonstrated the predominance of CD3-positive T cells in the lymphoid infiltration.Conclusions.Histopathological findings of the present study are consistent with a cellular immune response of natural killer cells against metastatic brain tumors, presumably stimulated by the ionizing energy of focused radiation.
Radiosurgery of vestibular schwannomas: summary of experience in 829 cases
Authors: Lunsford L. Dade , Niranjan Ajay , Flickinger John C. , Maitz Ann , Kondziolka Douglas 
Published: May 2009

Object.Management options for vestibular schwannomas (VSs) have greatly expanded since the introduction of stereotactic radiosurgery. Optimal outcomes reflect long-term tumor control, preservation of cranial nerve function, and retention of quality of life. The authors review their 15-year experience.Methods.Between 1987 and 2002, some 829 patients with VSs underwent gamma knife surgery (GKS). Dose selection, imaging, and dose planning techniques evolved between 1987 and 1992 but thereafter remained stable for 10 years. The average tumor volume was 2.5 cm3. The median margin dose to the tumor was 13 Gy (range 10–20 Gy).No patient sustained significant perioperative morbidity. The average duration of hospital stay was less than 1 day. Unchanged hearing preservation was possible in 50 to 77% of patients (up to 90% in those with intracanalicular tumors). Facial neuropathy risks were reduced to less than 1%. Trigeminal symptoms were detected in less than 3% of patients whose tumors reached the level of the trigeminal nerve. Tumor control rates at 10 years were 97% (no additional treatment needed).Conclusions.Superior imaging, multiple isocenter volumetric conformal dose planning, and optimal precision and dose delivery contributed to the long-term success of GKS, including in those patients in whom initial microsurgery had failed. Gamma knife surgery provides a low risk, minimally invasive treatment option for patients with newly diagnosed or residual VS. Cranial nerve preservation and quality of life maintenance are possible in long-term follow up.
The long-term results of gamma knife radiosurgery for hemangioblastomas of the brain
Authors: Wang En-Min , Pan Li , Wang Bing-Jiang , Zhang Nan , Zhou Liang-Fu , Dong Ya-Fei , Dai Jia-Zhong , Cai Pei-Wu , Chen Hong 
Published: May 2009

Object. The authors assessed the long-term result of gamma knife surgery (GKS) for hemangioblastomas of the brain (HABs) and show histopathological findings after GKS.
Methods. Thirty-five patients, 28 men and seven women, with a mean age of 36 years underwent GKS. Eighteen patients presented with multiple tumors and 17 with a solitary tumor. Twenty-one patients had von Hippel—Lindau (VHL) disease. The mean tumor diameter was 13 mm (range 5–55 mm). The mean follow up after GKS was 66 months (range 24–114 months). The mean prescription dose was 17.2 Gy (range 12–24 Gy) at the tumor margin. For tumors close to or within the brainstem a prescription dose of 12 to 13 Gy was used.
At the most recent follow up, 29 patients were alive, six were dead, and satisfactory tumor control had been achieved in 29. A stable or improved neurological status was obtained in 21 patients. Eight patients underwent open surgery because of tumor-associated cyst enlargement or the development of new tumors after GKS. Seven patients developed new tumors and five of them required a second GKS. The 1-year tumor control rate was 94%; 2 years, 85%; 3 years, 82%; 4 years, 79%; and 5 years, 71%. Histopathology showed that no tumor cells were found and there was degeneration and necrosis in a tumor nodule 48 months after GKS with a prescription dose of 18 Gy.
Conclusions. Gamma knife surgery was a useful choice for small- or medium-sized, solid HAB in the long term, especially when the tumor margin dose was 18 Gy. Although GKS can treat multiple tumors in a single session, for HABs associated with VHL disease, GKS faces the dual problems of tumor recurrence or development of a new tumor.
Tolerance dose in gamma knife surgery of lesions extending to the anterior visual pathway
Authors: Kenai Hiroyuki , Yamashita Masanori , Nakamura Takaharu , Asano Tomoshige , Sainoh Michifumi , Nagatomi Hirofumi 
Published: May 2009

Object.The authors performed a retrospective analysis of the radiation dose to the anterior visual pathway (AVP) to assess its tolerance to gamma knife surgery.Methods.They examined five cases followed for more than 3 years. The AVP was treated with 10-Gy doses or higher.The mean maximum delivered dose to the AVP was 14 Gy. Ten gray or more was delivered to 25.5% of the ipsilateral AVP, 12 Gy or more to 12.5% of the ipsilateral AVP, and 14 Gy or more to 5.7% of the ipsilateral AVP. Although the mean follow-up period was 40.8 months (36–51 months), no cases of visual function deterioration developed.Conclusions.The tolerance dose of the AVP is considered to be less than 8 to 10 Gy; however, although the delivered dose to the AVP definitely exceeded the tolerance dose in all five cases, no visual disturbance has been identified. Longer follow up is required before any final conclusions may be drawn. Nonetheless, it is suggested that a visual disturbance may be avoided by using careful accurate dose planning even if the dose delivered to the AVP is higher than currently believed to be acceptable.
Microvascular decompression after gamma knife surgery for trigeminal neuralgia: intraoperative findings and treatment outcomes
Authors: Shetter Andrew G. , Zabramski Joseph M. , Speiser Burton L. 
Published: May 2009

Object. The authors sought to determine whether the results of trigeminal microvascular decompression (MVD) are influenced by prior gamma knife surgery (GKS).
Methods. Gamma knife surgery is an established procedure for treating medically intractable trigeminal neuralgia but failures do occur. The authors assessed six patients (two men and four women; mean age 52 years) who experienced pain recurrence after GKS and elected to undergo trigeminal MVD via retrosigmoid craniotomy. Three patients underwent a single GKS to a maximal dose of 80 Gy, whereas three others underwent a second GKS to total of 120 to 135 Gy.
At surgery, none of the six patients demonstrated excess arachnoid thickening, grossly apparent changes in the nerve itself, or any other tissue alterations that made successful mobilization of a blood vessel from the trigeminal root entry zone technically more difficult. A single individual had a small atherosclerotic plaque in the superior cerebellar artery near its contact point with the trigeminal nerve. Follow up at a mean of 25.4 months (range 7.5–42 months) indicated that five patients were pain free. One patient had improved but still relied on medications for pain control.
Conclusions. In the authors' experience, trigeminal MVD can be performed without added difficulty in patients who have previously undergone GKS. The success rates seem similar to those normally associated with MVD. Patients who elect the less invasive option of GKS can be assured that trigeminal MVD remains a viable alternative at a later date if further surgery is required.
Diagnostic value of thallium-201 chloride single-photon emission computerized tomography in differentiating tumor recurrence from radiation injury after gamma knife surgery for metastatic brain tumors
Authors: Serizawa Toru , Saeki Naokatsu , Higuchi Yoshinori , Ono Junichi , Matsuda Shinji , Sato Makoto , Yanagisawa Masamichi , Iuchi Toshihiko , Nagano Osamu , Yamaura Akira 
Published: May 2009

Object.The authors assessed the diagnostic value of201Tl Cl single-photon emission computerized tomography (SPECT), performed after gamma knife surgery (GKS) for metastatic brain tumors in differentiating tumor recurrence from radiation injury.Methods.Of 6503 metastatic brain tumors treated with GKS,201Tl SPECT was required in 72 to differentiate between tumor recurrence and radiation injury. When the Tl index was greater than 5, the lesion was diagnosed as a tumor recurrence. When the index was < 3.0 it was called radiation injury. In cases with a Tl index between 3 and 5,201Tl SPECT was repeated once per month until the Tl index was greater than 5 or less than 3. If the Tl index fluctuated between 3 and 5 for 2 months, the lesion was diagnosed as radiation injury. The final diagnosis was based on histological examination or clinical course.The sensitivity of the method was 91%; thus201Tl SPECT is effective for differentiating between tumor recurrence and radiation injury in metastatic brain tumors treated with GKS. Caution is necessary, however, for the following reasons: 1) simple interinstitutional comparisons of Tl indices are not possible because measurement methods are institute specific; 2) steroid administration decreases the Tl index to a variable degree; and 3) a severe radiation injury lesion, as is often seen after repeated GKS or very high dose GKS, may have a Tl index greater than 5.Conclusions.Used with critical insight201Tl Cl SPECT can be useful in distinguishing between tumor regrowth and radiation necrosis in patients with cerebral metastases.
Racial differences in demographics, acute complications, and outcomes in patients with subarachnoid hemorrhage: a large patient series
Authors: Rosen David , Novakovic Roberta , Goldenberg Fernando D. , Huo Dezheng , Baldwin Maria E. , Frank Jeffrey I. , Rosengart Axel J. , Macdonald R. Loch 
Published: May 2009

Object
Few studies have focused on the impact of racial differences in demographics, clinical characteristics, acute complications, and outcomes of patients with aneurysmal subarachnoid hemorrhage (SAH). The purpose of this study was to examine this issue.

Methods
The authors evaluated prospectively collected data on 1711 adult patients with aneurysmal SAH who were entered into two randomized, double-blind, placebo-controlled trials conducted at neurosurgical centers in North America between 1991 and 1997. Admission characteristics, treatment modalities, in-hospital complications, and 3-month outcomes assessed by application of the Glasgow Outcome Scale were compared using the chi-square test, a t-test, the Wilcoxon rank-sum test, and multiple logistic regressions based on a significance level of 0.05 in 241 African-American, 1342 Caucasian, and 128 other racial minority patients.
Caucasian patients were significantly older than patients of other races (p < 0.0001). African-American patients more frequently had a history of hypertension (p < 0.0001) and an elevated blood pressure at the time of admission (p < 0.0001). African-Americans and other racial minorities were more likely to have internal carotid artery aneurysms and Caucasians were more likely to have posterior circulation aneurysms (p = 0.0002). Rates of in-hospital complications were not significantly different except that pulmonary edema occurred more commonly in Caucasians (p = 0.036). After an adjustment was made for significant admission characteristics, the 3-month outcome was not significantly different among the races.

Conclusions
Race was not found to be a prognostic factor for outcome after aneurysmal SAH. The higher SAH mortality rate previously observed in African-American patients is likely a result of a higher incidence of SAH in this group. These findings highlight the importance of primary prevention programs aimed at modifying risk factors for SAH.
Estrogen therapy for experimental intracerebral hemorrhage in rats
Authors: Nakamura Takehiro , Hua Ya , Keep Richard F. , Park Jung-Weon , Xi Guohua , Hoff Julian T. 
Published: May 2009

Object
The aims of this study were to determine the following: whether there are sex differences in intracerebral hemorrhage (ICH) induced brain injury in rats, whether delayed administration of 17β-estradiol can reduce ICH-induced brain damage, and whether these effects are estrogen receptor (ER)-dependent.

Methods
Male and female Sprague—Dawley rats received an infusion of 100 µl autologous whole blood into the right basal ganglia. Twenty-four hours later the rats were killed. The effects of 17β-estradiol on ICH-induced brain injury were examined by measuring brain edema and neurological deficits. Both ER-α and hemeoxygenase (HO)-1 were investigated through Western blot and immunohistochemical analysis.
Brain edema was significantly less severe in female compared with that in male rats. The ER antagonist ICI 182,780 exacerbated ICH-induced brain edema in female but not in male rats, indicating that ER-α activation during ICH is protective in female rats. Administration of exogenous 17β-estradiol in male, but not in female, rats significantly attenuated brain edema, neurological deficits, and ICH-induced changes in HO-1 when given 2 hours after hemorrhage. The effects of exogenous 17β-estradiol occurred through an ER-independent mechanism.

Conclusions
Results in this study indicate that 17β-estradiol could be a potential therapeutic agent for ICH.
Long-term benefits in quality of life provided by bilateral subthalamic stimulation in patients with Parkinson disease
Authors: Lyons Kelly E. , Pahwa Rajesh 
Published: May 2009

Object. The goals of this study were to evaluate long-term benefits in quality of life in patients with Parkinson disease (PD) after bilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) and to evaluate the relationship between improvements in motor function and quality of life.
Methods. Seventy-one patients who received bilateral STN stimulation implants and participated in follow-up review for at least 12 months were included in the study. Fifty-nine patients participated in a 12-month follow-up review and 43 patients in a follow-up review lasting at least 24 months. Patients' symptoms were assessed preoperatively by using the Unified PD Rating Scale (UPDRS) in the “medication-on” and “medication-off” conditions and quality of life was examined using the 39-item PD Questionnaire (PDQ-39). Patient evaluations were repeated postoperatively during periods of stimulation.
The UPDRS activities of daily living (ADL) and motor scores as well as the PDQ-39 total, mobility, ADL, emotional well-being, stigma, and bodily discomfort scores were significantly improved at 12 months compared with baseline scores; the UPDRS ADL and motor scores as well as the PDQ-39 total, mobility, ADL, stigma, and bodily discomfort scores were significantly improved at the longest follow-up examination compared with baseline scores. There was a strong correlation between UPDRS motor and ADL scores and the PDQ-39 total, mobility, and ADL scores. Further analyses indicated that improvements in tremor were only correlated with PDQ-39 ADL subscale scores and rigidity was not correlated with any aspect of quality of life. Nevertheless, bradykinesia was strongly correlated with improvements in the PDQ-39 total, mobility, and ADL scores.
Conclusions. Improvements in quality of life following bilateral DBS of the STN are maintained in the long term. These improvements are strongly correlated with improvements in motor function, primarily with regard to bradykinesia.
Discordance between functional magnetic resonance imaging during silent speech tasks and intraoperative speech arrest
Authors: Petrovich Nicole , Holodny Andrei I. , Tabar Viviane , Correa Denise D. , Hirsch Joy , Gutin Philip H. , Brennan Cameron W. 
Published: May 2009

Object. The goal of this study was to investigate discordance between the location of speech arrest during awake cortical mapping, a common intraoperative indicator of hemispheric dominance, and silent speech functional magnetic resonance (fMR) imaging maps of frontal language function.
Methods. Twenty-one cases were reviewed retrospectively. Images of silent speech fMR imaging activation were coregistered to anatomical MR images obtained for neuronavigation. These were compared with the intraoperative cortical photographs and the behavioral results of electrocorticography during awake craniotomy. An fMR imaging control study of three healthy volunteers was then conducted to characterize the differences between silent and vocalized speech fMR imaging protocols used for neurosurgical planning.
Conclusions. Results of fMR imaging showed consistent and predominant activation of the inferior frontal gyrus (IFG) during silent speech tasks. During intraoperative mapping, however, 16 patients arrested in the precentral gyrus (PRG), well posterior to the fMR imaging activity. Of those 16, 14 arrested only in the PRG and not in the IFG as silent speech fMR imaging predicted. The control fMR imaging study showed that vocalized speech fMR imaging shifts the location of the fMR imaging prediction to include the motor strip and may be more appropriate for neurosurgical planning.
Microsurgical robotic system for the deep surgical field: development of a prototype and feasibility studies in animal and cadaveric models
Authors: Morita Akio , Sora Shigeo , Mitsuishi Mamoru , Warisawa Shinichi , Suruman Katopo , Asai Daisuke , Arata Junpei , Baba Shoichi , Takahashi Hidechika , Mochizuki Ryo , Kirino Takaaki 
Published: May 2009

Object. To enhance the surgeon's dexterity and maneuverability in the deep surgical field, the authors developed a master—slave microsurgical robotic system. This concept and the results of preliminary experiments are reported in this paper.
Methods. The system has a master control unit, which conveys motion commands in six degrees of freedom (X, Y, and Z directions; rotation; tip flexion; and grasping) to two arms. The slave manipulator has a hanging base with an additional six degrees of freedom; it holds a motorized operating unit with two manipulators (5 mm in diameter, 18 cm in length). The accuracy of the prototype in both shallow and deep surgical fields was compared with routine freehand microsurgery. Closure of a partial arteriotomy and complete end-to-end anastomosis of the carotid artery (CA) in the deep operative field were performed in 20 Wistar rats. Three routine surgical procedures were also performed in cadavers.
The accuracy of pointing with the nondominant hand in the deep surgical field was significantly improved through the use of robotics. The authors successfully closed the partial arteriotomy and completely anastomosed the rat CAs in the deep surgical field. The time needed for stitching was significantly shortened over the course of the first 10 rat experiments. The robotic instruments also moved satisfactorily in cadavers, but the manipulators still need to be smaller to fit into the narrow intracranial space.
Conclusions. Computer-controlled surgical manipulation will be an important tool for neurosurgery, and preliminary experiments involving this robotic system demonstrate its promising maneuverability.