title: Detection of calcifications in retinoblastoma using gradient-echo MR imaging sequences: comparative study between in vivo MR imaging and ex vivo high-resolution CT.
abstract: OBJECTIVE
  Intratumoral calcifications are very important in the diagnosis of retinoblastoma. Although CT is considered superior in detecting calcification, its ionizing radiation, especially in patients with hereditary retinoblastoma, should be avoided. The purpose of our study was to validate T2*WI for the detection of calcification in retinoblastoma with ex vivo CT as the criterion standard.
  
  
  METHODS
  Twenty-two consecutive patients with retinoblastoma (mean age, 21 months; range, 1-71 months) with enucleation as primary treatment were imaged at 1.5T by using a dedicated surface coil. Signal-intensity voids indicating calcification on T2*WI were compared with ex vivo high-resolution CT, and correlation was scored by 2 independent observers as poor, good, or excellent. Other parameters included the shape and location of the signal-intensity voids. In 5 tumors, susceptibility-weighted images were evaluated.
  
  
  RESULTS
  All calcifications visible on high-resolution CT could be matched with signal-intensity voids on T2*WI, and correlation was scored as excellent in 17 (77%) and good in 5 (23%) eyes. In total, 93% (25/27) of the signal-intensity voids inside the tumor correlated with calcifications compared with none (0/8) of the signal-intensity voids outside the tumor. Areas of nodular signal-intensity voids correlated with calcifications in 92% (24/26), and linear signal-intensity voids correlated with hemorrhage in 67% (6/9) of cases. The correlation of signal-intensity voids on SWI was better in 4 of 5 tumors compared with T2*WI.
  
  
  CONCLUSIONS
  Signal-intensity voids on in vivo T2*WI correlate well with calcifications on ex vivo high-resolution CT in retinoblastoma. Gradient-echo sequences may be helpful in the differential diagnosis of retinoblastoma. The combination of funduscopy, sonography, and high-resolution MR imaging with gradient-echo sequences should become the standard diagnostic approach for retinoblastoma.
authors.affiliation: From the Departments of Radiology (F.R., P.d.G., M.C.d.J., J.A.C.) firazia.rodjan@slz.nl.
authors.forename: F
authors.initials: F
authors.lastname: Rodjan
authors.affiliation: From the Departments of Radiology (F.R., P.d.G., M.C.d.J., J.A.C.).
authors.forename: P
authors.initials: P
authors.lastname: de Graaf
authors.affiliation: Pathology (P.v.d.V.).
authors.forename: P
authors.initials: P
authors.lastname: van der Valk
authors.affiliation: Departments of Ophthalmology (T.H.).
authors.forename: T
authors.initials: T
authors.lastname: Hadjistilianou
authors.affiliation: Neuroimaging and Neurointerventional Unit (A.C., P.G.).
authors.forename: A
authors.initials: A
authors.lastname: Cerase
authors.affiliation: Pathology (P.T.), Azienda Ospedaliera e Universitaria, Santa Maria alle Scotte, Siena, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Toti
authors.affiliation: From the Departments of Radiology (F.R., P.d.G., M.C.d.J., J.A.C.).
authors.forename: M C
authors.initials: MC
authors.lastname: de Jong
authors.affiliation: Ophthalmology (A.C.M.), VU University Medical Center, Amsterdam, the Netherlands.
authors.forename: A C
authors.initials: AC
authors.lastname: Moll
authors.affiliation: From the Departments of Radiology (F.R., P.d.G., M.C.d.J., J.A.C.).
authors.forename: J A
authors.initials: JA
authors.lastname: Castelijns
authors.affiliation: Neuroimaging and Neurointerventional Unit (A.C., P.G.).
authors.forename: P
authors.initials: P
authors.lastname: Galluzzi
mesh_terms: D002114:Calcinosis / Q000000981:diagnostic imaging / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D019572:Retinal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D012175:Retinoblastoma / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed