title: Ocular volumetry using fast high-resolution MRI during visual fixation.
abstract: OBJECTIVE
  Volumetry may be useful for evaluating treatment response and prognosis of intraocular lesions. Phantom, volunteer, and patient studies were performed to determine whether ocular MR volumetry is reproducible.
  
  
  METHODS
  Half-Fourier single-shot RARE and FSPGR sequences at 1.5T with a 76-mm-diameter surface coil were optimized to obtain still ocular images. Volumetry accuracies of each sequence were compared with simulated subretinal phantom volumes. Ocular volumetry was performed in 15 volunteers twice in 1 week by using contiguous axial images of the globes while the subjects stared at a target, and images were acquired in 2 seconds before the subjects were instructed to blink, with this process repeated as necessary. Imaging, intraobserver, and interobserver reproducibility for volumes of the whole eyeball and anterior chamber were assessed. Ocular volumetry was also performed in 6 patients with intraocular tumors before and after treatment.
  
  
  RESULTS
  The phantom study demonstrated that measurement error rates with RARE were significantly lower than with FSPGR (P<.01). The volunteer study demonstrated excellent imaging and intraobserver reproducibility of RARE volumetry for whole eyeballs and anterior chambers (P<.01). Although no interobserver differences were observed in anterior chamber volume measurement (P=.33), there was a significant difference between the 2 observers in eyeball volume measurement (P<.01). Follow-up volumetric data were useful for treatment decisions in all patients.
  
  
  CONCLUSIONS
  Ocular volumetry from contiguous ultrafast RARE images obtained during visual fixation is feasible in volunteer and patient studies and is superior to FSPGR images.
authors.affiliation: Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, and Departmentof Clinical Radiology, Hiroshima University Hospital, Hiroshima, Japan. tntrad@msl.megaegg.ne.jp
authors.forename: K
authors.initials: K
authors.lastname: Tanitame
authors.forename: T
authors.initials: T
authors.lastname: Sone
authors.forename: T
authors.initials: T
authors.lastname: Miyoshi
authors.forename: N
authors.initials: N
authors.lastname: Tanitame
authors.forename: K
authors.initials: K
authors.lastname: Otani
authors.forename: Y
authors.initials: Y
authors.lastname: Akiyama
authors.forename: M
authors.initials: M
authors.lastname: Takasu
authors.forename: S
authors.initials: S
authors.lastname: Date
authors.forename: Y
authors.initials: Y
authors.lastname: Kiuchi
authors.forename: K
authors.initials: K
authors.lastname: Awai
mesh_terms: D000328:Adult; D016477:Artifacts; D002830:Choroid Neoplasms / Q000473:pathology; D005123:Eye / Q000033:anatomy & histology / Q000473:pathology*; D005128:Eye Diseases / Q000473:pathology*; D005131:Eye Injuries / Q000473:pathology; D005134:Eye Neoplasms / Q000473:pathology; D005240:Feasibility Studies; D005260:Female; D006391:Hemangioma / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods* / Q000592:standards*; D008297:Male; D008545:Melanoma / Q000473:pathology; D015588:Observer Variation; D009929:Organ Size; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012163:Retinal Detachment / Q000473:pathology; D012175:Retinoblastoma / Q000473:pathology