The role of diffusion-weighted MRI in the evaluation of pediatric patient with orbital masses

Background
Orbital lesions represent a spectrum of benign and malignant lesions in children that can be challenging to diagnose and treat. Imaging plays an important role in diagnosis, owing to a potentially limited clinical examination and risks associated with biopsy. MRI is a powerful tool for imaging the orbit, owing to the excellent tissue contrast it provides.


Aim
This study aims at assessing the ability of diffusion-weighted MRI to differentiate the benign from malignant orbital lesions.


Patients and methods
This study population included 50 pediatric patients; they all attended with orbital lesions. All patients had fulfilled specific inclusion and exclusion criteria. The patients were evaluated by MRI orbit and diffusion study in an attempt to differentiate the benign orbital lesions from malignant ones.


Results
The pool of our study is 50 pediatric patients (26 females and 24 males) with orbital lesions. The patients’ age ranged from 3 weeks to 18 years. A total of 27 (54%) patients were diagnosed as having malignant masses and 23 (46%) patients had benign lesions. Retinoblastoma is the commonest between the pathological diagnoses (28%) followed by rhabdomyosarcoma (18%). The calculated apparent diffusion coefficient (ADC) values of the lesions ranged from 0.69 to 0.95×10−3 mm2/s, with cutoff value of 1.04×10−3 mm2/s between benign and malignant orbital masses.


Conclusion
We concluded that the combination of conventional MRI finding and ADC calculation together with clinical finding could improve the diagnostic efficacy of MRI in the differentiation between benign and malignant orbital masses in pediatric age group with considering the cutoff ADC value between benign and malignant orbital masses.