title: Transsphenoidal pituitary macroadenomas resection guided by PoleStar N20 low-field intraoperative magnetic resonance imaging: comparison with early postoperative high-field magnetic resonance imaging.
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).
  
  
  CONCLUSIONS
  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.
authors: Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors: Jin-Song
authors: JS
authors: Wu
authors: Xue-Fei
authors: XF
authors: Shou
authors: Cheng-Jun
authors: CJ
authors: Yao
authors: Yong-Fei
authors: YF
authors: Wang
authors: Dong-Xiao
authors: DX
authors: Zhuang
authors: Ying
authors: Y
authors: Mao
authors: Shi-Qi
authors: SQ
authors: Li
authors: Liang-Fu
authors: LF
authors: Zhou
mesh_terms: D000236:Adenoma / Q000473:pathology* / Q000601:surgery; D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007432:Intraoperative Period / Q000295:instrumentation* / Q000379:methods; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods; D019635:Neurosurgical Procedures / Q000295:instrumentation / Q000379:methods; D010911:Pituitary Neoplasms / Q000473:pathology* / Q000601:surgery; D011388:Prolactin / Q000378:metabolism; D012658:Sella Turcica / Q000473:pathology* / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D011388:Prolactin