title: Comparison of single time-point [111-In] pentetreotide SPECT/CT with dual time-point imaging of neuroendocrine tumors.
abstract: OBJECTIVE
  to determine whether single time-point single-photon emission computed tomography-computed tomography (SPECT/CT) somatostatin receptor imaging can replace traditional dual time-point planar and SPECT somatostatin receptor scintigraphy for evaluation of neuroendocrine tumors.
  
  
  METHODS
  twenty-four patients (9 males, 15 females; mean age: 56 years; range: 14-82 years) underwent [111-In] pentetreotide scintigraphy, with planar whole-body images acquired at 24 and 48 hours after injection and abdominal SPECT/CT at 24 hours postinjection. Two blinded readers independently interpreted each study, using single time-point (24 hours planar and SPECT/CT) and separately using dual time-point (24- and 48-hours planar, and 24-hour SPECT without CT) image information. Consensus interpretations were compared with surgical pathology, or clinical and radiologic follow-up for at least 12 months.
  
  
  RESULTS
  Interobserver agreement was excellent (κ = 0.86) for single time-point imaging, and good (κ = 0.56) with dual time-point imaging. After consensus review, single time-point imaging identified pathologic lesions in 11 of 12 subjects with diagnosis of NET at follow-up, and in 0 of 12 subjects without NET (sensitivity 92%; specificity 100%). Dual time-point imaging performed similarly, but missed an additional NET case (sensitivity 83%; specificity 100%). After review of SPECT/CT, the readers considered that additional 48 hours imaging was not necessary in the majority of cases, indicating high degree of confidence with the single time-point imaging.
  
  
  CONCLUSIONS
  [111-In] pentetreotide SPECT/CT imaging at 24 hours identifies pathologic disease sites and distinguishes physiologic activity equally well compared to traditional strategies using 2 imaging days. Routine use of SPECT/CT will allow single time-point imaging without loss of diagnostic accuracy, enhancing patient convenience, and clinical throughput.
authors.affiliation: Departments of Nuclear Medicine, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Ka Kit
authors.initials: KK
authors.lastname: Wong
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Wynn
authors.forename: Jamie
authors.initials: J
authors.lastname: Myles
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Ackermann
authors.forename: Kirk A
authors.initials: KA
authors.lastname: Frey
authors.forename: Anca M
authors.initials: AM
authors.lastname: Avram
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging*; D013004:Somatostatin / Q000031:analogs & derivatives*; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging; D055815:Young Adult
chemical_list: D013004:Somatostatin; C081788:pentetreotide