title: Hippocampal volumes in patients exposed to low-dose radiation to the basal brain. A case-control study in long-term survivors from cancer in the head and neck region.
abstract: BACKGROUND
  An earlier study from our group of long time survivors of head and neck cancer who had received a low radiation dose to the hypothalamic-pituitary region, with no signs of recurrence or pituitary dysfunction, had their quality of life (QoL) compromised as compared with matched healthy controls. Hippocampal changes have been shown to accompany several psychiatric conditions and the aim of the present study was to test whether the patients' lowered QoL was coupled to a reduction in hippocampal volume.
  
  
  METHODS
  Patients (11 men and 4 women, age 31-65) treated for head and neck cancer 4-10 years earlier and with no sign of recurrence or pituitary dysfunction, and 15 matched controls were included. The estimated radiation doses to the basal brain including the hippocampus (1.5 - 9.3 Gy) had been calculated in the earlier study. The hippocampal volumetry was done on coronal sections from a 1.5 T MRI scanner. Measurements were done by two independent raters, blinded to patients and controls, using a custom method for computer assisted manual segmentation. The volumes were normalized for intracranial volume which was also measured manually. The paired t test and Wilcoxon's signed rank test were used for the main statistical analysis.
  
  
  RESULTS
  There was no significant difference with respect to left, right or total hippocampal volume between patients and controls. All mean differences were close to zero, and the two-tailed 95% confidence interval for the difference in total, normalized volume does not include a larger than 8% deficit in the patients.
  
  
  CONCLUSIONS
  The study gives solid evidence against the hypothesis that the patients' lowered quality of life was due to a major reduction of hippocampal volume.
authors.affiliation: Institute of Neuroscience and Physiology, Sahlgrenska University Hospital, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Olsson
authors.forename: Carl
authors.initials: C
authors.lastname: Eckerström
authors.forename: Gertrud
authors.initials: G
authors.lastname: Berg
authors.forename: Magnus
authors.initials: M
authors.lastname: Borga
authors.forename: Sven
authors.initials: S
authors.lastname: Ekholm
authors.forename: Gudmundur
authors.initials: G
authors.lastname: Johannsson
authors.forename: Susanne
authors.initials: S
authors.lastname: Ribbelin
authors.forename: Göran
authors.initials: G
authors.lastname: Starck
authors.forename: Anna
authors.initials: A
authors.lastname: Wysocka
authors.forename: Elisabet
authors.initials: E
authors.lastname: Löfdahl
authors.forename: Helge
authors.initials: H
authors.lastname: Malmgren
mesh_terms: D000328:Adult; D000368:Aged; D001007:Anxiety / Q000209:etiology / Q000523:psychology; D001921:Brain / Q000473:pathology / Q000528:radiation effects*; D016022:Case-Control Studies; D003863:Depression / Q000209:etiology / Q000523:psychology; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000150:complications / Q000401:mortality / Q000532:radiotherapy*; D006624:Hippocampus / Q000473:pathology* / Q000528:radiation effects; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000528:radiation effects; D009367:Neoplasm Staging; D011379:Prognosis; D011788:Quality of Life; D011829:Radiation Dosage; D011836:Radiation Tolerance; D015996:Survival Rate