Faculty Collaboration Database

Indeterminate orbital masses: restricted diffusion at MR imaging with echo-planar diffusion-weighted imaging predicts malignancy. Radiology 2010 Aug;256(2):554-64

Date

07/27/2010

Pubmed ID

20656840

DOI

10.1148/radiol.10091956

Scopus ID

2-s2.0-77955148880 (requires institutional sign-in at Scopus site)   132 Citations

Abstract

PURPOSE: To determine whether magnetic resonance (MR) imaging with diffusion-weighted (DW) imaging can help discriminate between radiologically indeterminate benign and malignant orbital masses and to identify optimal apparent diffusion coefficient (ADC) thresholds for such discrimination.

MATERIALS AND METHODS: Informed consent was waived for this HIPAA-compliant institutional review board-approved retrospective study. Forty-seven orbital masses imaged with echo-planar DW imaging were identified in 47 patients (25 female patients, 22 male patients; average age, 35 years). A fellowship-trained orbital surgeon determined reference-standard diagnoses on the basis of chart review, and a neuroradiology fellow and senior neuroradiologist who were blinded to the diagnoses selected a region of interest for each lesion by consensus. ADC was calculated from signal intensity on DW images obtained with b = 1000 and b = 0 sec/mm(2). Lesion ADC was also compared with that of normal-appearing white matter (ADC ratio). The Student t test was used to compare groups. Receiver operating characteristic analysis was performed. Intraobserver agreement was assessed with a repeat data collection.

RESULTS: Malignant lesions had lower ADCs than benign lesions, irrespective of patient age (P < .02) and in adults specifically (P < .05). Lymphomas had lower ADCs than pseudotumors (P < .001). An ADC of less than 1.0 x 10(-3) mm(2)/sec and an ADC ratio of less than 1.2 were optimal for predicting malignancy (sensitivity, 63% for both; specificity, 84% and 90%, respectively; and accuracy, 77% and 81%, respectively). Lymphoma was differentiated from pseudotumor with 100% accuracy (in 16 of 16 cases) by using these values. Infiltrative lesions that were hypointense on T2-weighted images were better characterized with DW imaging than lesions that were hyperintense or well defined.

CONCLUSION: Echo-planar DW MR imaging can help characterize indeterminate orbital masses.

Author List

Sepahdari AR, Aakalu VK, Setabutr P, Shiehmorteza M, Naheedy JH, Mafee MF

Author

Vinay Kumar Aakalu MPH, MD Chair, Professor in the Ophthalmology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adolescent
Adult
Aged
Aged, 80 and over
Child
Child, Preschool
Diffusion Magnetic Resonance Imaging
Echo-Planar Imaging
Female
Humans
Infant
Infant, Newborn
Male
Middle Aged
Orbital Neoplasms
Reproducibility of Results
Sensitivity and Specificity
Subtraction Technique
Young Adult