title: Impact of ultra-low-field intraoperative magnetic resonance imaging on extent of resection and frequency of tumor recurrence in 104 surgically treated nonfunctioning pituitary adenomas.
abstract: OBJECTIVE
  To analyze the impact of intraoperative ultra-low-field magnetic resonance imaging (MRI) on the extent of tumor resection in nonfunctioning pituitary adenomas (NFPAs).
  
  
  METHODS
  Retrospective analysis was performed of 104 consecutive cases undergoing intraoperative MRI-guided transsphenoidal surgery for NFPA. General patient data; endocrinologic parameters; neurologic examinations; preoperative and postoperative symptoms; preoperative, intraoperative, and postoperative imaging; and proliferation index were evaluated with an overall mean follow-up of 34 months.
  
  
  RESULTS
  The use of intraoperative MRI led to an increase of the overall remission rate by 52.2%, from 44.2% to 67.3%. Tumor characteristics such as size and invasiveness had an important impact on postoperative remission rate. In patients with macroadenoma and without previous pituitary surgery, a remission rate of 82.2% was achieved. Overall, the sensitivity of intraoperative MRI in the study was 32.4%. There were no false-positive interpretations. A higher proliferation index was found in the 15 patients with postoperative enlargement of residual adenomas or tumor recurrence compared with the other patients of the study group.
  
  
  CONCLUSIONS
  This study shows that the outcome of surgical treatment of NFPAs was improved by the use of intraoperative MRI owing to more radical resection. The remission rate seems to depend on tumor characteristics. Recurrent disease might be reduced by the use of intraoperative MRI leading to more complete surgical resection of NFPAs.
authors.affiliation: Department of Neurosurgery, Division of Endocrinology and Diabetes, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Hlavica
authors.forename: David
authors.initials: D
authors.lastname: Bellut
authors.forename: Doreen
authors.initials: D
authors.lastname: Lemm
authors.forename: Christoph
authors.initials: C
authors.lastname: Schmid
authors.forename: René Ludwig
authors.initials: RL
authors.lastname: Bernays
mesh_terms: D000236:Adenoma / Q000473:pathology* / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods / Q000592:standards; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D010911:Pituitary Neoplasms / Q000473:pathology* / Q000601:surgery*; D011182:Postoperative Care / Q000379:methods; D011183:Postoperative Complications / Q000473:pathology; D011300:Preoperative Care / Q000379:methods; D012074:Remission Induction; D012086:Reoperation; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D055815:Young Adult