Woon Wee Chong, Yee Yau Chian, Nurul Marliana Md Zaid, G Kalai Amuthan Gurusamy, Khai Yen Lim, Mohd Boniami Yazid, Mohammad Zikri Ahmad, Mohd Hashairi Fauzi, Shaik Farid Abdull Wahab

AIM

To demonstrate sonography of foreign body within cranial cavity via temporal window of transcranial ultrasonography in pediatric.

METHODS

A 5- year -old girl was brought in to the emergency room with a history of sudden fall from a couch following loud thudding noise at home with bleeding from the left frontal region of the scalp.

Post-fall noted the child have expressive aphasia and having weakness over the right side of the body. Physical examination revealed upper motor neuron lesion involving the left corticospinal and corticobulbar tract.

Cranial nerves and cerebellar function was intact. There was a penetrating wound over the scalp, but no foreign body was detected around the wound.

Immediate skull radiograph done in the district hospital showed presence of an oval shaped radiopaque object. Bedside ultrasound was performed on the cranium.

Linear ultrasound probe was placed over bilateral temporal of the child to obtain both transverse and vertical view.

A 2.9cm X 1.65cm oval shaped hyperechoic structure with an acoustic shadowing was identified over the left temporal region suspecting of bullet. The findings was subsequently confirmed by computer tomography of the brain.

RESULTS

Penetrating wound injury is common presentation in Emergency Department, but ones that had retained foreign body intracranially is not common.

Failure to identify the foreign body can lead to multiple complications.

This child presented with penetrating wound over the left frontal scalp had neurological deficit including left corticospinal and corticobulbar tract. High index of suspicion of foreign body and intracranial bleed need to be excluded.

The skull radiograph confirm presence of foreign body but the exact location is indeterminate.

Sonography has a reported sensitivity up to 95% detection of foreign body. Non-opaque foreign bodies are visualized as hyper-echoic foci with accompanying acoustic shadows. A hypoechoic halo surrounding the foreign body is sometimes seen, which represents edema, abscess or granulation tissue.

A high-frequency probe is favourable as it generates short wavelength ultrasound and therefore better axial resolution, will allow for detection of the smallest and superficial foreign bodies.

In this case, it was a great challenge to detect an intracranial foreign body via transcranial ultrasound after closure of anterior fontanelle. As ultrasound wave unable to transmit well through high density structure (such as skull) because of reflection.

Temporal window was the preferred acoustic window in this case as temporal bone is the thinnest among the cranial bones.

CONCLUSION

Despite of limited acoustic window of transcranial ultrasound approach and attenuation of the ultrasound energy transmission through thickness and porosity of the bone around the acoustic window, ultrasound could still be an inexpensive and convenient tool to be used during initial assessment to detect the intracranial retained foreign body.