title: Three-dimensional susceptibility-weighted imaging and two-dimensional T2*-weighted gradient-echo imaging of intratumoral hemorrhages in pediatric diffuse intrinsic pontine glioma.
abstract: BACKGROUND
  We compared the sensitivity and specificity of T2*-weighted gradient-echo imaging (T2*-GRE) and susceptibility-weighted imaging (SWI) in determining prevalence and cumulative incidence of intratumoral hemorrhages in children with diffuse intrinsic pontine glioma (DIPG) undergoing antiangiogenic and radiation therapy.
  
  
  METHODS
  Patients were recruited from an institutional review board-approved prospective phase I trial of vandetanib administered in combination with radiation therapy. Patient consent was obtained before enrollment. Consecutive T2*-GRE and SWI exams of 17 patients (F/M: 9/8; age 3-17 years) were evaluated. Two reviewers (R1 and R2) determined the number and size of hemorrhages at baseline and multiple follow-ups (92 scans, mean 5.4/patient). Statistical analyses were performed using descriptive statistics, graphical tools, and mixed-effects Poisson regression models.
  
  
  RESULTS
  Prevalence of hemorrhages at diagnosis was 41% and 47%; the cumulative incidences of hemorrhages at 6 months by T2*-GRE and SWI were 82% and 88%, respectively. Hemorrhages were mostly petechial; 9.7% of lesions on T2*-GRE and 5.2% on SWI were hematomas (>5 mm). SWI identified significantly more hemorrhages than T2*-GRE did. Lesions were missed or misinterpreted in 36/39 (R1/R2) scans by T2*-GRE and 9/3 scans (R1/R2) by SWI. Hemorrhages had no clinically significant neurological correlates in patients.
  
  
  CONCLUSIONS
  SWI is more sensitive than T2*-GRE in detecting hemorrhages and differentiating them from calcification, necrosis, and artifacts. Also, petechial hemorrhages are more common in DIPG at diagnosis than previously believed and their number increases during the course of treatment; hematomas are rare.
authors.affiliation: Department of Radiological Sciences, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Mail Stop 220, Memphis, TN 38105, USA.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Löbel
authors.forename: Jan
authors.initials: J
authors.lastname: Sedlacik
authors.forename: Noah D
authors.initials: ND
authors.lastname: Sabin
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kocak
authors.forename: Alberto
authors.initials: A
authors.lastname: Broniscer
authors.forename: Claudia M
authors.initials: CM
authors.lastname: Hillenbrand
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Patay
mesh_terms: D000293:Adolescent; D020295:Brain Stem Neoplasms / Q000098:blood supply / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005910:Glioma / Q000150:complications* / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D020300:Intracranial Hemorrhages / Q000209:etiology* / Q000473:pathology*; D008297:Male; D011149:Pons / Q000098:blood supply / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity