TRANSSPHENOIDAL PITUITARY MACROADENOMAS RESECTION GUIDED BY POLESTAR N20 LOW-FIELD INTRAOPERATIVE MAGNETIC RESONANCE IMAGING

Neurosurgery ◽  
2009 ◽  
Vol 65 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Jin-Song Wu ◽  
Xue-Fei Shou ◽  
Cheng-Jun Yao ◽  
Yong-Fei Wang ◽  
Dong-Xiao Zhuang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Transsphenoidal Surgery ◽  
High Field ◽  
Intraoperative Imaging ◽  
Tumor Resection ◽  
Residual Tumor ◽  
Resonance Imaging ◽  
Low Field ◽  
Pituitary Macroadenomas

ABSTRACT OBJECTIVE To evaluate the applicability of low-field intraoperative magnetic resonance imaging (iMRI) during transsphenoidal surgery of pituitary macroadenomas. METHODS Fifty-five transsphenoidal surgeries were performed for macroadenomas (modified Hardy's Grade II–IV) resections. All of the surgical processes were guided by real-time updated contrast T1-weighted coronal and sagittal images, which were acquired with 0.15 Tesla PoleStar N20 iMRI (Medtronic Navigation, Louisville, CO). The definitive benefits as well as major drawbacks of low-field iMRI in transsphenoidal surgery were assessed with respect to intraoperative imaging, tumor resection control, comparison with early postoperative high-field magnetic resonance imaging, and follow-up outcomes. RESULTS Intraoperative imaging revealed residual tumor and guided extended tumor resection in 17 of 55 cases. As a result, the percentage of gross total removal of macroadenomas increased from 58.2% to 83.6%. The accuracy of imaging evaluation of low-field iMRI was 81.8%, compared with early postoperative high-field MRI (Correlation coefficient, 0.677; P <0.001). A significantly lower accuracy was identified with low-field iMRI in 6 cases with cavernous sinus invasion (33.3%) in contrast to the 87.8% found with other sites (Fisher's exact test, P <0.001). CONCLUSION The PoleStar N20 low-field iMRI navigation system is a promising tool for safe, minimally invasive, endonasal, transsphenoidal pituitary macroadenomas resection. It enables neurosurgeons to control the extent of tumor resection, particularly for suprasellar tumors, ensuring surgical accuracy and safety, and leading to a decreased likelihood of repeat surgeries. However, this technology is still not satisfying in estimating the amount of the parasellar residual tumor invading into cavernous sinus, given the false or uncertain images generated by low-field iMRI in this region, which are difficult to discriminate between tumor remnant and blood within the venous sinus.

Limited Benefit of Intraoperative Low-field Magnetic Resonance Imaging in Craniopharyngioma Surgery

Neurosurgery ◽  
2003 ◽  
Vol 53 (1) ◽  
pp. 72-81 ◽  
Author(s):  
Christopher Nimsky ◽  
Oliver Ganslandt ◽  
Bernd Hofmann ◽  
Rudolf Fahlbusch
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Transsphenoidal Surgery ◽  
Intraoperative Imaging ◽  
Complete Removal ◽  
Resonance Imaging ◽  
Tumor Removal ◽  
Low Field ◽  
Low Field Mri

Abstract OBJECTIVE To investigate the benefit of intraoperative low-field magnetic resonance imaging (MRI) in craniopharyngioma surgery. METHODS We used a 0.2-T Magnetom Open scanner (Siemens Medical Solutions, Erlangen, Germany) that was located in a radiofrequency-shielded operating theater for intraoperative MRI. The head of the patient was placed in the fringe field of the scanner, so that standard microinstruments could be used. In transsphenoidal surgery, T1-weighted coronal and sagittal images were acquired. In transcranial surgery, a three-dimensional, gradient echo, T1-weighted, fast low-angle shot sequence was measured, thus allowing multiplanar reformatting. RESULTS A total of 21 surgical procedures in craniopharyngioma patients were investigated. In 10 patients, a bifrontal-translaminar approach was used; in 6 patients, the craniopharyngioma was removed via a transsphenoidal approach; and in 5 patients, intraoperative MRI was used to monitor cyst puncture and aspiration. In the craniotomy group, intraoperative imaging depicted a clear tumor remnant in one patient, which was subsequently removed. In another patient, an area of contrast enhancement was interpreted as artifact; however, postoperative follow-up at 3 months was suspicious for a minor remnant. Two of the eight patients with complete removal developed a recurrence during the follow-up period. In the group of patients who underwent primary transsphenoidal surgery (n = 4), complete removal was estimated by the surgeon in three cases. Intraoperative imaging depicted a remaining tumor in one case, leading to further tumor removal; however, follow-up revealed recurrent cysts. CONCLUSION Intraoperative low-field MRI allows an ultraearly evaluation of the extent of tumor removal in craniopharyngioma surgery in most cases. Imaging showing an incomplete resection offers the chance for further tumor removal during the same operation. However, intraoperative low-field MRI depicting a complete resection does not exclude craniopharyngioma recurrence.

Quantification of Glioma Removal by Intraoperative High-Field Magnetic Resonance Imaging: An Update

Neurosurgery ◽  
2011 ◽  
Vol 69 (4) ◽  
pp. 852-863 ◽  
Author(s):  
Daniela Kuhnt ◽  
Oliver Ganslandt ◽  
Sven-Martin Schlaffer ◽  
Michael Buchfelder ◽  
Christopher Nimsky
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Field ◽  
Tumor Volume ◽  
Tumor Resection ◽  
World Health ◽  
Incomplete Resection ◽  
Resonance Imaging ◽  
Glioma Surgery ◽  
Who Grade

Abstract BACKGROUND: The beneficial role of the extent of resection (EOR) in glioma surgery in correlation to increased survival remains controversial. However, common literature favors maximum EOR with preservation of neurological function, which is shown to be associated with a significantly improved outcome. OBJECTIVE: In order to obtain a maximum EOR, it was examined whether high-field intraoperative magnetic resonance imaging (iMRI) combined with multimodal navigation contributes to a significantly improved EOR in glioma surgery. METHODS: Two hundred ninety-three glioma patients underwent craniotomy and tumor resection with the aid of intraoperative 1.5 T MRI and integrated multimodal navigation. In cases of remnant tumor, an update of navigation was performed with intraoperative images. Tumor volume was quantified pre- and intraoperatively by segmentation of T2 abnormality in low-grade and contrast enhancement in high-grade gliomas. RESULTS: In 25.9% of all cases examined, additional tumor mass was removed as a result of iMRI. This led to complete tumor resection in 20 cases, increasing the rate of gross-total removal from 31.7% to 38.6%. In 56 patients, additional but incomplete resection was performed because of the close location to eloquent brain areas. Volumetric analysis showed a significantly (P < .01) reduced mean percentage of tumor volume following additional further resection after iMRI from 33.5% ± 25.1% to 14.7% ± 23.3% (World Health Organization [WHO] grade I, 32.8% ± 21.9% to 6.1% ± 18.8%; WHO grade II, 24.4% ± 25.1% to 10.8% ± 11.0%; WHO grade III, 35.1% ± 27.3% to 24.8% ± 26.3%; WHO grade IV, 34.2% ± 23.7% to 1.2% ± 16.2%). CONCLUSION: MRI in conjunction with multimodal navigation and an intraoperative updating procedure enlarges tumor-volume reduction in glioma surgery significantly without higher postoperative morbidity.

IMPACT OF INTRAOPERATIVE HIGH-FIELD MAGNETIC RESONANCE IMAGING GUIDANCE ON GLIOMA SURGERY

Neurosurgery ◽  
2009 ◽  
Vol 64 (6) ◽  
pp. 1073-1081 ◽  
Author(s):  
Mustafa Aziz Hatiboglu ◽  
Jeffrey S. Weinberg ◽  
Dima Suki ◽  
Ganesh Rao ◽  
Sujit S. Prabhu ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Field ◽  
Residual Tumor ◽  
Gross Total Resection ◽  
Resonance Imaging ◽  
Tumor Removal ◽  
Total Resection ◽  
Glioma Resection ◽  
Additional Tumor

Abstract OBJECTIVE To determine the impact of intraoperative magnetic resonance imaging (iMRI) on the decision to proceed with additional glioma resection during surgery and to maximize extent of resection (EOR). METHODS Patients who underwent craniotomy for glioma resection with high-field iMRI guidance were prospectively evaluated between September 2006 and August 2007. Volumetric analysis and EOR were assessed with iMRI, using postcontrast T1-weighted images for tumors showing contrast enhancement and T2-weighted images for nonenhancing tumors. RESULTS Forty-six patients underwent resection using iMRI guidance, with iMRI being used to evaluate the EOR in 44 patients and for reregistration in 2 patients. Surgery was terminated after iMRI in 23 patients (52%) because gross total resection was achieved or because of residual tumor infiltration in an eloquent brain region. Twenty-one patients (47%) underwent additional resection of residual tumor after iMRI. For enhancing gliomas, the median EOR increased significantly from 84% (range, 59%–97%) to 99% (range, 85%–100%) with additional tumor removal after iMRI (P < 0.001). For nonenhancing gliomas, the median EOR increased (from 63% to 80%) with additional tumor removal after iMRI, but not significantly, owing to the small sample size (7 patients). Overall, the EOR increased from 76% (range, 35%–97%) to 96% (range, 48%–100%) (P < 0.001). Gross total resection was achieved after additional tumor removal after iMRI in 15 of 21 patients (71%). Overall, 29 patients (65%) experienced gross total resection, and in 15 (52%), this was achieved with the contribution of iMRI. CONCLUSION High-field iMRI is a safe and reliable technique, and its use optimizes the extent of glioma resection.

Usefulness of Intraoperative Ultra Low-field Magnetic Resonance Imaging in Glioma Surgery

2008 ◽  
Vol 63 (suppl_4) ◽  
pp. ONS257-ONS267 ◽  
Author(s):  
Christian Senft ◽  
Volker Seifert ◽  
Elvis Hermann ◽  
Kea Franz ◽  
Thomas Gasser
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Tumor Resection ◽  
Extent Of Resection ◽  
Resonance Imaging ◽  
Complete Tumor Resection ◽  
Glioma Surgery ◽  
Low Field ◽  
Low Field Mri ◽  
Complete Tumor

Abstract Objective: The aim of this study was to demonstrate the usefulness of a mobile, intraoperative 0.15-T magnetic resonance imaging (MRI) scanner in glioma surgery. Methods: We analyzed our prospectively collected database of patients with glial tumors who underwent tumor resection with the use of an intraoperative ultra low-field MRI scanner (PoleStar N-20; Odin Medical Technologies, Yokneam, Israel/Medtronic, Louisville, CO). Sixty-three patients with World Health Organization Grade II to IV tumors were included in the study. All patients were subjected to postoperative 1.5-T imaging to confirm the extent of resection. Results: Intraoperative image quality was sufficient for navigation and resection control in both high-and low-grade tumors. Primarily enhancing tumors were best detected on T1-weighted imaging, whereas fluid-attenuated inversion recovery sequences proved best for nonenhancing tumors. Intraoperative resection control led to further tumor resection in 12 (28.6%) of 42 patients with contrast-enhancing tumors and in 10(47.6%) of 21 patients with noncontrast-enhancing tumors. In contrast-enhancing tumors, further resection led to an increased rate of complete tumor resection (71.2 versus 52.4%), and the surgical goal of gross total removal or subtotal resection was achieved in all cases (100.0%). In patients with noncontrast-enhancing tumors, the surgical goal was achieved in 19 (90.5%) of 21 cases, as intraoperative MRI findings were inconsistent with postoperative high-field imaging in 2 cases. Conclusion: The use of the PoleStar N-20 intraoperative ultra low-field MRI scanner helps to evaluate the extent of resection in glioma surgery. Further tumor resection after intraoperative scanning leads to an increased rate of complete tumor resection, especially in patients with contrast-enhancing tumors. However, in noncontrast-enhancing tumors, the intraoperative visualization of a complete resection seems less specific, when compared with postoperative 1.5-T MRI.

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