Bedside detection of acute epidural hematoma by transcranial sonography in a head-injured patient

Sir: A 24 year-old boy was brought to the ED with head injury after a motorcycle accident. On his arrival, he was alert, and his GCS was 14 (V5, M5, E4). A head CT scan was performed, and a small (max width 0.9 cm) temporal epidural hematoma was observed. Since its small dimension, it was not scheduled for surgery, and a new CT scan after 4 h was planned. Transcranial echography (TCE) was performed with a 2.0 MHz transducer insonating in a transverse plane through the temporal acoustic bone window: after identifying the arteries of the circle of Willis, the depth of the insonation window was adjusted (usually 16 cm), so that the butterfly-shaped mesencephalic brainstem and the contralateral skull became visible [1]. In these conditions an epidural hematoma was observed as an hyperechogenic image just inside the skull (Fig. 1). One hour later, the clinical condition was unchanged. TCE was repeated, and an enlargement of the hematoma with a maximum width of 2.5 cm (Fig. 1). CT scan was immediately performed, and the enlargement was confirmed. The hematoma was promptly evacuated, and 7 days later the patient was discharged from the hospital with no neurological deficit. Recently, transcranial sonography of brain parenchyma in adults has been proposed by several authors for the evaluation of the ventricular system, monitoring of midline shift, diagnosis and follow-up of intracranial mass lesions. Seidel G et al. [2] found a good correlation between CT and TCE in the measurements of third (r = 0.83, P \ 0.0001) and lateral ventricles (r = 0.73, P \ 0.0001). Similar agreement between these two imaging techniques were observed by Tang et al. [3] in the measurement of midline shift (gamma = 0.91, P \ 0.01). Maurer et al. [4] used TCE to differentiate ischemic from hemorrhagic stroke. On 151 patients, 18 (12%) had no sufficient acoustic bone window. Of the remaining 133 patients, they observed that a correct sonographic diagnosis was made in the 95% of the cases (126 patients). To our knowledge, this is the first report that shows echographical finding of acute epidural hematoma in adults. Actually, we found that, thanks to the improvement of technology of ultrasound machines, high resolution images of the contralateral skull may be often obtained by the transtemporal approach, so that epidural mass lesion can be rapidly detected by trained physicians. According with recent guidelines [5], morphologic criteria for surgery are based on the volume and thickness of the hematoma, and on the extent of midline shift. All these data may be obtained by transcranial sonography that can be used bedside, together with CT scan, to monitor these patients in case of non-operative management. In conclusion, in our opinion transcranial echography may be a useful tool to monitor epidural hematomas before clinical conditions deteriorate. In all patients with a sufficient acoustic window in the temporal bone, it is a rapid and noninvasive neuroimaging technique that can complement the results of CT scan, and may help to reduce delays in surgical management. Further prospective studies are needed to evaluate sensitivity, specificity and accuracy of this technique