Arterial spin labeling and diffusion-weighted MR imaging: Utility in differentiating idiopathic orbital inflammatory pseudotumor from orbital lymphoma

• Published in: Clinical imaging Vol. 71; pp. 63 - 68
• Main Authors: Eissa, Lamya, Abdel Razek, Ahmed Abdel Khalek, Helmy, Eman
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-03-2021; Elsevier Limited
• Subjects: Archives & records; Arterial spin labeling; Biopsy; Blood flow; Diagnosis, Differential; Diffusion; Diffusion coefficient; Diffusion Magnetic Resonance Imaging; Diffusion-weighted imaging; Humans; Inflammation; Labeling; Lymphoma; Magnetic resonance imaging; Observers; Orbital Neoplasms; Orbital Pseudotumor; Pathology; Pseudotumors; Retrospective Studies; Spin labeling; Spin Labels; Standard deviation; Thresholds; Diffusion-weighted imaging; DWI; Arterial spin labeling; Orbital pseudotumor; ASL; Lymphoma; IOIP
• ISSN: 0899-7071; 1873-4499
• DOI: 10.1016/j.clinimag.2020.10.057

To assess arterial spin-labeling (ASL) and diffusion-weighted imaging (DWI) and in combination for differentiating between idiopathic orbital inflammatory pseudotumor (IOIP) and orbital lymphoma.
A retrospective study was done on 37 untreated patients with orbital masses, suspected to be IOIP or orbital lymphoma that underwent ASL and DWI of the orbit. Quantitative measurement of tumor blood flow (TBF) and apparent diffusion coefficient (ADC) of the orbital lesion was done.
There was a significant difference (P = 0.001) in TBF between patients with IOIP (n = 21) (38.1 ± 6.2, 40.3 ± 7.1 ml/100 g/min) and orbital lymphoma (n = 16) (55.5 ± 7.1, 56.8 ± 7.9 ml/100 g/min) for both observers respectively. Thresholds of TBF used for differentiating IOIP from orbital lymphoma were 48, 46 ml/100 g/min revealed area under the curve (AUC) of (0.958 and 0.921), and accuracy of (86% and 83%) for both observers respectively. There was a significant difference (P = 0.001) in ADC between patients with IOIP (1.04 ± 0.19, 1.12 ± 0.23 × 10−3 mm2/s) and orbital lymphoma (0.69 ± 0.10, 0.72 ± 0.11 × 10−3 mm2/s) for both observers respectively. Thresholds of ADC used for differentiating IOIP from orbital lymphoma were 0.84 and 0.86 × 10−3 mm2/s with AUC of (0.933 and 0.920), and accuracy of 89% and 90% for both observers respectively. The combined TBF and ADC used for differentiating IOIP from orbital lymphoma had AUC of (0.973 and 0.970) and accuracy of (91% and 89%) for both observers respectively.
TBF and ADC alone and in combination are useful for differentiating IOIP from orbital lymphoma.
•Significant difference (P = 0.001) in TBF between patients with IOIP and orbital lymphoma•Significant difference (P = 0.001) in ADC between patients with IOIP and orbital lymphoma•Combined TBF and ADC can differentiate IOIP from orbital lymphoma.