The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Adam E Hansen - One of the best experts on this subject based on the ideXlab platform.
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evaluation of dynamic contrast enhanced t1 weighted perfusion mri in the differentiation of tumor recurrence from Radiation Necrosis
Neuroradiology, 2013Co-Authors: Vibeke Andree Larsen, H Simonsen, Ian Law, Henrik Larsson, Adam E HansenAbstract:Introduction To investigate if perfusion measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to differentiate Radiation Necrosis from tumor recurrence in patients with high-grade glioma.
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evaluation of dynamic contrast enhanced t1 weighted perfusion mri in the differentiation of tumor recurrence from Radiation Necrosis
Neuroradiology, 2013Co-Authors: Vibeke Andree Larsen, H Simonsen, Henrik Larsson, Adam E HansenAbstract:Introduction To investigate if perfusion measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to differentiate Radiation Necrosis from tumor recurrence in patients with high-grade glioma.
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evaluation of dynamic contrast enhanced t1 weighted perfusion mri in the differentiation of tumor recurrence from Radiation Necrosis
Neuroradiology, 2013Co-Authors: Vibeke Andree Larsen, Ian Law, Henrik Larsson, Helle J Simonsen, Adam E HansenAbstract:To investigate if perfusion measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to differentiate Radiation Necrosis from tumor recurrence in patients with high-grade glioma. The study was approved by the institutional review board and informed consent was obtained from all subjects. 19 patients were recruited following surgery and Radiation therapy for glioma. Patients had contrast enhancing lesions, which during the standard MRI examination could not be exclusively determined as recurrence or Radiation Necrosis. DCE-MRI was used to measure cerebral blood volume (CBV), blood–brain barrier (BBB) permeability and cerebral blood flow (CBF). Subjects also underwent FDG-PET and lesions were classified as either metabolically active or inactive. Follow-up clinical MRI and lesion histology in case of additional tissue resection was used to determine whether lesions were regressing or progressing. Fourteen enhancing lesions could be classified as progressing (11) or regressing (three). An empirical threshold of 2.0 ml/100 g for CBV allowed detection of regressing lesions with a sensitivity of 100 % and specificity of 100 %. FDG-PET and DCE-MRI agreed in classification of tumor status in 13 out of the 16 cases where an FDG-PET classification was obtained. In two of the remaining three patients, MRI follow-up and histology was available and both indicated that the DCE-MRI answer was correct. CBV measurements using DCE-MRI may predict the status of contrast enhancing lesions and give results very similar to FDG-PET with regards to differentiation between tumor recurrence and Radiation Necrosis.
Vibeke Andree Larsen - One of the best experts on this subject based on the ideXlab platform.
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evaluation of dynamic contrast enhanced t1 weighted perfusion mri in the differentiation of tumor recurrence from Radiation Necrosis
Neuroradiology, 2013Co-Authors: Vibeke Andree Larsen, H Simonsen, Ian Law, Henrik Larsson, Adam E HansenAbstract:Introduction To investigate if perfusion measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to differentiate Radiation Necrosis from tumor recurrence in patients with high-grade glioma.
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evaluation of dynamic contrast enhanced t1 weighted perfusion mri in the differentiation of tumor recurrence from Radiation Necrosis
Neuroradiology, 2013Co-Authors: Vibeke Andree Larsen, H Simonsen, Henrik Larsson, Adam E HansenAbstract:Introduction To investigate if perfusion measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to differentiate Radiation Necrosis from tumor recurrence in patients with high-grade glioma.
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evaluation of dynamic contrast enhanced t1 weighted perfusion mri in the differentiation of tumor recurrence from Radiation Necrosis
Neuroradiology, 2013Co-Authors: Vibeke Andree Larsen, Ian Law, Henrik Larsson, Helle J Simonsen, Adam E HansenAbstract:To investigate if perfusion measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to differentiate Radiation Necrosis from tumor recurrence in patients with high-grade glioma. The study was approved by the institutional review board and informed consent was obtained from all subjects. 19 patients were recruited following surgery and Radiation therapy for glioma. Patients had contrast enhancing lesions, which during the standard MRI examination could not be exclusively determined as recurrence or Radiation Necrosis. DCE-MRI was used to measure cerebral blood volume (CBV), blood–brain barrier (BBB) permeability and cerebral blood flow (CBF). Subjects also underwent FDG-PET and lesions were classified as either metabolically active or inactive. Follow-up clinical MRI and lesion histology in case of additional tissue resection was used to determine whether lesions were regressing or progressing. Fourteen enhancing lesions could be classified as progressing (11) or regressing (three). An empirical threshold of 2.0 ml/100 g for CBV allowed detection of regressing lesions with a sensitivity of 100 % and specificity of 100 %. FDG-PET and DCE-MRI agreed in classification of tumor status in 13 out of the 16 cases where an FDG-PET classification was obtained. In two of the remaining three patients, MRI follow-up and histology was available and both indicated that the DCE-MRI answer was correct. CBV measurements using DCE-MRI may predict the status of contrast enhancing lesions and give results very similar to FDG-PET with regards to differentiation between tumor recurrence and Radiation Necrosis.
Henrik Larsson - One of the best experts on this subject based on the ideXlab platform.
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evaluation of dynamic contrast enhanced t1 weighted perfusion mri in the differentiation of tumor recurrence from Radiation Necrosis
Neuroradiology, 2013Co-Authors: Vibeke Andree Larsen, H Simonsen, Ian Law, Henrik Larsson, Adam E HansenAbstract:Introduction To investigate if perfusion measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to differentiate Radiation Necrosis from tumor recurrence in patients with high-grade glioma.
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evaluation of dynamic contrast enhanced t1 weighted perfusion mri in the differentiation of tumor recurrence from Radiation Necrosis
Neuroradiology, 2013Co-Authors: Vibeke Andree Larsen, H Simonsen, Henrik Larsson, Adam E HansenAbstract:Introduction To investigate if perfusion measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to differentiate Radiation Necrosis from tumor recurrence in patients with high-grade glioma.
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evaluation of dynamic contrast enhanced t1 weighted perfusion mri in the differentiation of tumor recurrence from Radiation Necrosis
Neuroradiology, 2013Co-Authors: Vibeke Andree Larsen, Ian Law, Henrik Larsson, Helle J Simonsen, Adam E HansenAbstract:To investigate if perfusion measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to differentiate Radiation Necrosis from tumor recurrence in patients with high-grade glioma. The study was approved by the institutional review board and informed consent was obtained from all subjects. 19 patients were recruited following surgery and Radiation therapy for glioma. Patients had contrast enhancing lesions, which during the standard MRI examination could not be exclusively determined as recurrence or Radiation Necrosis. DCE-MRI was used to measure cerebral blood volume (CBV), blood–brain barrier (BBB) permeability and cerebral blood flow (CBF). Subjects also underwent FDG-PET and lesions were classified as either metabolically active or inactive. Follow-up clinical MRI and lesion histology in case of additional tissue resection was used to determine whether lesions were regressing or progressing. Fourteen enhancing lesions could be classified as progressing (11) or regressing (three). An empirical threshold of 2.0 ml/100 g for CBV allowed detection of regressing lesions with a sensitivity of 100 % and specificity of 100 %. FDG-PET and DCE-MRI agreed in classification of tumor status in 13 out of the 16 cases where an FDG-PET classification was obtained. In two of the remaining three patients, MRI follow-up and histology was available and both indicated that the DCE-MRI answer was correct. CBV measurements using DCE-MRI may predict the status of contrast enhancing lesions and give results very similar to FDG-PET with regards to differentiation between tumor recurrence and Radiation Necrosis.
Samuel T Chao - One of the best experts on this subject based on the ideXlab platform.
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Radiation Necrosis from stereotactic radiosurgery how do we mitigate
Current Treatment Options in Oncology, 2021Co-Authors: Balamurugan Vellayappan, Tresa Mcgranahan, Jerome J Graber, Lynne Taylor, Vyshak Alva Venur, Richard G Ellenbogen, Andrew E Sloan, Kristin J Redmond, Matthew Foote, Samuel T ChaoAbstract:Intracranial stereotactic radiosurgery (SRS) is an effective and convenient treatment for many brain conditions. Data regarding safety come mostly from retrospective single institutional studies and a small number of prospective studies. Variations in target delineation, treatment delivery, imaging follow-up protocols and dose prescription limit the interpretation of this data. There has been much clinical focus on Radiation Necrosis (RN) in particular, as it is being increasingly recognized on follow-up imaging. Symptomatic RN may be treated with medical therapy (such as corticosteroids and bevacizumab) with surgical resection being reserved for refractory patients. Nevertheless, RN remains a challenging condition to manage, and therefore upfront patient selection for SRS remains critical to provide complication-free control. Mitigation strategies need to be considered in situations where the baseline risk of RN is expected to be high—such as large target volume or re-irRadiation. These may involve reduction in the prescribed dose or hypofractionated stereotactic Radiation therapy (HSRT). Recently published guidelines and international meta-analysis report the benefit of HSRT in larger lesions, without compromising control rates. However, careful attention to planning parameters and SRS techniques still need to be adhered, even with HSRT. In cases where the risk is deemed to be high despite mitigation, a combination approach of surgery with or without post-operative Radiation should be considered.
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treatment of cerebral Radiation Necrosis with bevacizumab the cleveland clinic experience
American Journal of Clinical Oncology, 2015Co-Authors: Neda H Sadraei, Samuel T Chao, Erin S Murphy, John H Suh, Saurabh Dahiya, Kwabena Oseiboateng, Hao Xie, David M Peereboom, Glen StevensAbstract:Background:Cerebral Radiation Necrosis (RN) is a devastating complication of Radiation therapy for brain tumors. Recent studies have explored the role of bevacizumab, a humanized monoclonal antibody directed against vascular endothelial growth factor in the treatment of RN of the brain. We report 24
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challenges with the diagnosis and treatment of cerebral Radiation Necrosis
International Journal of Radiation Oncology Biology Physics, 2013Co-Authors: Samuel T Chao, Manmeet S Ahluwalia, Gene H Barnett, Glen Stevens, Erin S Murphy, Abigail L Stockham, Kevin Shiue, John H SuhAbstract:The incidence of Radiation Necrosis has increased secondary to greater use of combined modality therapy for brain tumors and stereotactic radiosurgery. Given that its characteristics on standard imaging are no different that tumor recurrence, it is difficult to diagnose without use of more sophisticated imaging and nuclear medicine scans, although the accuracy of such scans is controversial. Historically, treatment had been limited to steroids, hyperbaric oxygen, anticoagulants, and surgical resection. A recent prospective randomized study has confirmed the efficacy of bevacizumab in treating Radiation Necrosis. Novel therapies include using focused interstitial laser thermal therapy. This article will review the diagnosis and treatment of Radiation Necrosis.
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conventional mri does not reliably distinguish Radiation Necrosis from tumor recurrence after stereotactic radiosurgery
Journal of Neuro-oncology, 2012Co-Authors: Abigail L Stockham, Gene H Barnett, John H Suh, Andrew L Tievsky, Shlomo A Koyfman, Chandana A Reddy, Michael A Vogelbaum, Samuel T ChaoAbstract:Distinguishing Radiation Necrosis (RN) from tumor recurrence after stereotactic radiosurgery (SRS) for brain metastases is challenging. This study assesses the sensitivity (SN) and specificity (SP) of an MRI-based parameter, the “lesion quotient” (LQ), in characterizing tumor progression from RN. Records of patients treated with SRS for brain metastases between 01/01/1999 and 12/31/2009 and with histopathologic analysis of a subsequent contrast enhancing enlarging lesion at the treated site at a single institution were examined. The LQ, the ratio of maximal nodular cross sectional area on T2-weighted imaging to the corresponding maximal cross sectional area of T1-contrast enhancement, was calculated by a neuroradiologist blinded to the histopathological outcome. Cutoffs of 0.6 have been previously suggested to have correlated with RN, mixed findings and tumor recurrence, respectively. These cutoff values were evaluated for SN, SP, positive predictive value (PPV) and negative predictive value (NPV). Logistic regression analysis evaluated for associated clinical factors. For the 51 patients evaluated, the SN, SP, PPV and NPV for identifying RN (LQ 0.6) were 59, 41, 62 and 39 %, respectively. Standard MRI techniques do not reliably discriminate between tumor progression and RN after treatment with SRS for brain metastases. Additional imaging modalities are warranted to aid in distinguishing between these diagnoses.
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laser interstitial thermal therapy for focal cerebral Radiation Necrosis a case report and literature review
Stereotactic and Functional Neurosurgery, 2012Co-Authors: Gazanfar Rahmathulla, Samuel T Chao, Pablo F Recinos, Jose E Valerio, G O BarnettAbstract:Whole-brain radiotherapy and stereotactic radiosurgery (SRS) play a central role in the treatment of metastatic brain tumors. Radiation Necrosis occurs in 5% of patients and can be very difficult to treat. The available treatment options for Radiation Necrosis include prolonged high-dose corticosteroids, hyperbaric oxygen, anticoagulation, bevacizumab, and surgical resection. We present the first report and results using laser-interstitial thermal therapy (LITT) for medically refractory radioNecrosis. A 74-year-old diabetic patient who had a history of non-small cell lung cancer with brain metastases and subsequent treatment with SRS, presented with a focal lesion in the left centrum semiovale with progressively worsening edema. Image findings were consistent with Radiation Necrosis that was refractory despite prolonged, high-dose steroid therapy. His associated comorbidities obviated alternative interventions and the lesion was not in a location amenable to surgical resection. We used laser thermal ablation to treat the biopsy-proven radioNecrosis. The procedure was tolerated well and the patient was discharged 48 hours postoperatively. Imaging at 7-week follow-up showed near complete resolution of the edema and associated mass effect. Additionally, the patient was completely weaned off steroids. To our knowledge this is the first report using LITT for the treatment of focal Radiation Necrosis. LITT may be an effective treatment modality for patients with medically refractory Radiation Necrosis with lesions not amenable to surgical decompression.
William A Friedman - One of the best experts on this subject based on the ideXlab platform.
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can standard magnetic resonance imaging reliably distinguish recurrent tumor from Radiation Necrosis after radiosurgery for brain metastases a radiographic pathological study
Neurosurgery, 2008Co-Authors: Ivan M Dequesada, Ronald G Quisling, Anthony T Yachnis, William A FriedmanAbstract:OBJECTIVE: Stereotactic radiosurgery is a commonly used treatment method in the management of metastatic brain tumors. When lesions enlarge after radiosurgery, it may represent tumor regrowth, Radiation Necrosis, or both. The purpose of this study was to determine whether standard magnetic resonance imaging (MRI) sequences could reliably distinguish between these pathological possibilities. METHODS: A total of 619 patients, reported in a previous study, were treated with radiosurgery for metastatic brain tumors. Of those patients, 59 underwent subsequent craniotomy for symptomatic lesion enlargement. Of those 59 patients, 32 had complete preoperative MRI studies as well as surgical pathology reports. The following MRI features were analyzed in this subset of patients: arteriovenous shunting, gyriform lesion or edema distribution, perilesional edema, cyst formation, and pattern of enhancement. A novel radiographic feature, called the lesion quotient, which is the ratio of the nodule as seen on T2 imaging to the total enhancing area on T1 imaging, was also analyzed. RESULTS: Sensitivity, specificity, and predictive values were computed for each radiographic characteristic. Lesions containing only Radiation Necrosis never displayed gyriform lesion/edema distribution, marginal enhancement, or solid enhancement. All lesions exhibited perilesional edema. A lesion quotient of 0.6 or greater was seen in all cases of recurrent tumor, a lesion quotient greater than 0.3 was seen in 19 of 20 cases of combination pathology, and a lesion quotient of 0.3 or less was seen in 4 of 5 cases of Radiation Necrosis. The lesion quotient correlated with the percentage of tumor identified on pathological specimens. CONCLUSION: The lesion quotient appears to reliably identify pure Radiation Necrosis on standard sequence MRI. Other examined radiographic features, including arteriovenous shunting, gyriform lesion/edema distribution, enhancement pattern, and cyst formation, achieved 80% or greater predictive value but had either low sensitivity or low specificity.
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can standard magnetic resonance imaging reliably distinguish recurrent tumor from Radiation Necrosis after radiosurgery for brain metastases a radiographic pathological study
Neurosurgery, 2008Co-Authors: Ivan M Dequesada, Ronald G Quisling, Anthony T Yachnis, William A FriedmanAbstract:OBJECTIVE: Stereotactic radiosurgery is a commonly used treatment method in the management of metastatic brain tumors. When lesions enlarge after radiosurgery, it may represent tumor regrowth, Radiation Necrosis, or both. The purpose of this study was to determine whether standard magnetic resonance imaging (MRI) sequences could reliably distinguish between these pathological possibilities. METHODS: A total of 619 patients, reported in a previous study, were treated with radiosurgery for metastatic brain tumors. Of those patients, 59 underwent subsequent craniotomy for symptomatic lesion enlargement. Of those 59 patients, 32 had complete preoperative MRI studies as well as surgical pathology reports. The following MRI features were analyzed in this subset of patients: arteriovenous shunting, gyriform lesion or edema distribution, perilesional edema, cyst formation, and pattern of enhancement. A novel radiographic feature, called the lesion quotient, which is the ratio of the nodule as seen on T2 imaging to the total enhancing area on T1 imaging, was also analyzed. RESULTS: Sensitivity, specificity, and predictive values were computed for each radiographic characteristic. Lesions containing only Radiation Necrosis never displayed gyriform lesion/edema distribution, marginal enhancement, or solid enhancement. All lesions exhibited perilesional edema. A lesion quotient of 0.6 or greater was seen in all cases of recurrent tumor, a lesion quotient greater than 0.3 was seen in 19 of 20 cases of combination pathology, and a lesion quotient of 0.3 or less was seen in 4 of 5 cases of Radiation Necrosis. The lesion quotient correlated with the percentage of tumor identified on pathological specimens. CONCLUSION: The lesion quotient appears to reliably identify pure Radiation Necrosis on standard sequence MRI. Other examined radiographic features, including arteriovenous shunting, gyriform lesion/edema distribution, enhancement pattern, and cyst formation, achieved 80% or greater predictive value but had either low sensitivity or low specificity.
