Quantitative imaging analysis of posterior fossa ependymoma location in children.
OBJECTIVE
Imaging descriptions of posterior fossa ependymoma in children have focused on magnetic resonance imaging (MRI) signal and local anatomic relationships with imaging location only recently used to classify these neoplasms. We developed a quantitative method for analyzing the location of ependymoma in the posterior fossa, tested its effectiveness in distinguishing groups of tumors, and examined potential associations of distinct tumor groups with treatment and prognostic factors.


METHODS
Pre-operative MRI examinations of the brain for 38 children with histopathologically proven posterior fossa ependymoma were analyzed. Tumor margin contours and anatomic landmarks were manually marked and used to calculate the centroid of each tumor. Landmarks were used to calculate a transformation to align, scale, and rotate each patient's image coordinates to a common coordinate space. Hierarchical cluster analysis of the location and morphological variables was performed to detect multivariate patterns in tumor characteristics. The ependymomas were also characterized as "central" or "lateral" based on published radiological criteria. Therapeutic details and demographic, recurrence, and survival information were obtained from medical records and analyzed with the tumor location and morphology to identify prognostic tumor characteristics.


RESULTS
Cluster analysis yielded two distinct tumor groups based on centroid location The cluster groups were associated with differences in PFS (p = .044), "central" vs. "lateral" radiological designation (p = .035), and marginally associated with multiple operative interventions (p = .064).


CONCLUSIONS
Posterior fossa ependymoma can be objectively classified based on quantitative analysis of tumor location, and these classifications are associated with prognostic and treatment factors.
Department of Diagnostic Imaging, St. Jude Children's Research Hospital, 262 Danny Thomas Place (MS 220), Memphis, TN, 38105, USA. noah.sabin@stjude.org.
Noah D
ND
Sabin
Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN, USA.
Thomas E
TE
Merchant
Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN, USA.
Xingyu
X
Li
Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN, USA.
Yimei
Y
Li
Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN, USA.|Semmes-Murphey Neurologic and Spine Institute, Memphis, TN, USA.
Paul
P
Klimo
Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN, USA.|Semmes-Murphey Neurologic and Spine Institute, Memphis, TN, USA.
Frederick A
FA
Boop
Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA.
David W
DW
Ellison
Department of Diagnostic Imaging, St. Jude Children's Research Hospital, 262 Danny Thomas Place (MS 220), Memphis, TN, 38105, USA.
Robert J
RJ
Ogg
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004806:Ependymoma / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D015192:Infratentorial Neoplasms / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male
Ependymoma; Image analysis; Pediatric; Quantitative imaging