title: Prediction of postoperative diabetes insipidus using morphological hyperintensity patterns in the pituitary stalk on magnetic resonance imaging after transsphenoidal surgery for sellar tumors.
abstract: OBJECTIVE
  Diabetes insipidus (DI) remains a complication of transsphenoidal surgery (TSS) for sellar and parasellar tumors. Antidiuretic hormone (ADH) appears as hyper intensity (HI) in the pituitary stalk and the posterior lobe of the pituitary gland on T1-weighted magnetic resonance (MR) imaging. Its disappearance from the posterior lobe occurs with DI, indicating a lack of ADH. The appearance of HI in the pituitary stalk indicates disturbances in ADH transport.
  
  
  METHODS
  This retrospective study included 172 patients undergoing TSS for sellar tumors at our institute from 2006 to 2014. Sequential T1-weighted MR images without enhancement were evaluated for HI in the pituitary stalk and the posterior lobe to assess the localization of ADH before and at intervals after TSS. DI was assessed pre- and postoperatively. HI in the pituitary stalk showed the following morphology: (1) ovoid in the distal end of the pituitary stalk (group A), (2) linear in the distal part of the pituitary stalk (group B), (3) linear in the whole pituitary stalk (group C).
  
  
  RESULTS
  Preoperative DI occurred in 6 patients (3.5 %) with no HI observed in the posterior lobe. Postoperative DI was transient in 82 patients (47.7 %), and permanent in 11 (6.4 %). One week after surgery, HI was absent in the posterior lobe in 74 patients (43.0 %), and present in the pituitary stalk in 99 patients (57.6 %); both were significantly correlated with postoperative DI (p < 0.001). The absence of HI in the posterior lobe (A, 48.9 %; B, 68.3 %; C, 92.3 %), persistence of DI (A, 3.7 days; B, 45.9 days; C, 20.5 months), and duration until HI recovery in the posterior lobe (A, 3.6 months; B, 6.8 months; C, 22.9 months) were greatest in group C, followed by group B, and then group A. Fourteen group A patients did not have postoperative DI despite having HI in the pituitary stalk and the posterior lobe. Four group C patients developed permanent DI with persistence HI in the pituitary stalk.
  
  
  CONCLUSIONS
  HI in the pituitary stalk and its absence in the posterior lobe indicated postoperative DI, which was transient if HI was detected in the pituitary stalk. DI duration could be predicted by the length of HI in the pituitary stalk, which corresponded to the degree of ADH transport obstruction.
authors: Department of Neurosurgery, Graduate School of Medical Science, Kanazawa University, Kanazawa, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan. yahayashi@med.kanazawa-u.ac.jp.
authors: Yasuhiko
authors: Y
authors: Hayashi
authors: Department of Neurosurgery, Graduate School of Medical Science, Kanazawa University, Kanazawa, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan.
authors: Daisuke
authors: D
authors: Kita
authors: Department of Neurosurgery, Graduate School of Medical Science, Kanazawa University, Kanazawa, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan.
authors: Takuya
authors: T
authors: Watanabe
authors: Department of Neurosurgery, Graduate School of Medical Science, Kanazawa University, Kanazawa, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan.
authors: Issei
authors: I
authors: Fukui
authors: Department of Neurosurgery, Graduate School of Medical Science, Kanazawa University, Kanazawa, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan.
authors: Yasuo
authors: Y
authors: Sasagawa
authors: Department of Neurosurgery, Graduate School of Medical Science, Kanazawa University, Kanazawa, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan.
authors: Masahiro
authors: M
authors: Oishi
authors: Department of Neurosurgery, Kanazawa Medical University, Kanazawa, Japan.
authors: Osamu
authors: O
authors: Tachibana
authors: Department of Radiology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan.
authors: Fumiaki
authors: F
authors: Ueda
authors: Department of Neurosurgery, Graduate School of Medical Science, Kanazawa University, Kanazawa, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan.
authors: Mitsutoshi
authors: M
authors: Nakada
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003919:Diabetes Insipidus / Q000000981:diagnostic imaging* / Q000453:epidemiology; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010902:Pituitary Gland / Q000000981:diagnostic imaging* / Q000601:surgery; D010911:Pituitary Neoplasms / Q000601:surgery; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000453:epidemiology; D012189:Retrospective Studies; D055815:Young Adult
keywords: Diabetes insipidus; Magnetic resonance imaging; Pituitary stalk; Posterior lobe; Transsphenoidal surgery