CT and MRI findings of intraorbital wooden foreign bodies

Abstract

AIM: To characterize the computed tomography (CT) and magnetic resonance imaging (MRI) findings of intraorbital wooden foreign bodies (IOWFB) and to evaluate their diagnostic value.

MATERIALS AND METHODS

CT and MRI findings of 10 patients with surgically proven IOWFB were retrospectively examined. The image features of IOWFB assessed included location, geometry, margin, size, attenuation on CT, and signal intensity on MRI.

RESULTS

On CT (n=10) and MRI (n=5), the IOWFB appeared as rods in eight cases and as wedges in two cases. All 10 IOWFB exhibited clear margins. The sizes of IOWFB ranged from 8 × 6.4 mm to 46 × 5.5 mm, with a mean of 26.6 × 5.4 mm. Hypoattenuation between the attenuation of fat and air was observed in eight patients (acute stage) with IOWFB, with a mean value of −252.77 HU (Hounsfield Unit) on CT. One of these patients (subacute stage) showed hyperattenuation with a mean value of 97.28 HU above that of extraocular muscle on CT performed 15 days post injury. In two patients (chronic stage), the IOWFB exhibited hyperattenuation on CT and were encapsulated by granulation tissue with attenuation of 79.08 HU and 212.95 HU. On the MRI of all five patients, the IOWFB showed hypointense signal intensity on T1-weighted images and hypointense signal intensity on T2-weighted/fat-suppressed T2-weighted images.

CONCLUSION

CT and MRI offer respective advantages in the diagnosis of IOWFB. CT is the preferred modality for patients with suspected IOWFB, while MRI provides valuable supplementary information.