title: 3 Tesla magnetic resonance imaging with and without corticotropin releasing hormone stimulation for the detection of microadenomas in Cushing's syndrome.
abstract: OBJECTIVE
  We sought to determine if higher resolution 3 Tesla (T) magnetic resonance imaging (MRI) with or without ovine corticotropin releasing hormone (o-CRH) stimulation would increase the sensitivity for detection of pituitary microadenomas in ACTH-dependent Cushing's syndrome (CS).
  
  
  METHODS
  We prospectively identified 23 patients over a 2-year period with clinical and biochemical evidence of ACTH-dependent CS with no lesion (n = 11) or equivocal lesion (n = 10) on 1.5T MRI. Subsequently, two additional MRIs were performed in random order: 3T nonstimulated MRI or 3T MRI with o-CRH in all patients. Three neuroradiologists reviewed all examinations in a randomized blinded fashion. Patients were divided into four groups, depending on the outcome of their evaluation and treatment for CS. Two patients had to be excluded, and so we report on 21 subjects.
  
  
  RESULTS
  Both 3T MRI without (P < 0.016) and with o-CRH stimulation (P < 0.013) was significantly more sensitive for detection of pituitary microadenomas than 1.5T MRI for Group 1 (definitive proof of Cushing's disease, n = 10). Group 2 (those in group 1, plus three patients where dynamic/invasive testing suggested pituitary source) also showed a significant (P < 0.012) advantage for 3T. There was no difference between the 3T and the 3T o-CRH examinations for any of the pulse sequences. We did not observe a statistically significant difference in other patient groups [patients with recurrent CD (n = 6) and patients with ectopic CS (n = 2)].
  
  
  CONCLUSIONS
  The results of our prospective blinded studies suggest that 3T MRI of pituitary gland should be considered in evaluation of patients with ACTH-dependent CD when 1.5T imaging is negative or equivocal.
authors.affiliation: Division of Endocrinology, Metabolism and Nutrition, Mayo College of Medicine, Rochester, MN 55905, USA.
authors.forename: Dana
authors.initials: D
authors.lastname: Erickson
authors.forename: Bradley
authors.initials: B
authors.lastname: Erickson
authors.forename: Robert
authors.initials: R
authors.lastname: Watson
authors.forename: Alice
authors.initials: A
authors.lastname: Patton
authors.forename: John
authors.initials: J
authors.lastname: Atkinson
authors.forename: Fredric
authors.initials: F
authors.lastname: Meyer
authors.forename: Todd
authors.initials: T
authors.lastname: Nippoldt
authors.forename: Paul
authors.initials: P
authors.lastname: Carpenter
authors.forename: Neena
authors.initials: N
authors.lastname: Natt
authors.forename: Adrian
authors.initials: A
authors.lastname: Vella
authors.forename: Prabin
authors.initials: P
authors.lastname: Thapa
mesh_terms: D049913:ACTH-Secreting Pituitary Adenoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000236:Adenoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000328:Adult; D000368:Aged; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology / Q000627:therapeutic use*; D003480:Cushing Syndrome / Q000000981:diagnostic imaging*; D003940:Diagnostic Techniques, Endocrine; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D013268:Stimulation, Chemical; D047368:Tumor Burden / Q000187:drug effects / Q000502:physiology; D055815:Young Adult
chemical_list: D003346:Corticotropin-Releasing Hormone