[Clinical value of bedside ultrasonography in craniectomized patients]

Twenty-five patients underwent bedside ultrasonographic examination through a postoperative skull defect, and the images were compared with axial computed tomography (CT) scans. The patients included 12 with cerebrovascular disease, two with brain tumor, one with a brain abscess, and 10 with head injury. Clear ultrasonographic images were obtained in all patients except one who had undergone a suboccipital craniectomy. Ultrasound was most useful when hydrocephalus was present, in which cases, regardless of the cause, hypo-echoic dilated third and lateral ventricles were demonstrated. In one case, it was decided to emplace a ventriculoperitoneal shunt on the basis of the results of serial sonography, which documented ventricular enlargement. Intracerebral hematomas also were identified by ultrasonography. Acute hematomas, such as subarachnoid blood clots persisting after clipping of an aneurysm, appeared as hyper-echoic images, whereas, late hematomas were depicted as hypo-echoic images. In one case, a recurrent brain tumor was depicted as a hyper-echoic mass. In multiple-trauma patients with head injury who were too unstable to be moved for CT scanning, ultrasound was extremely useful. So-called "delayed traumatic intracerebral hematoma" was identified in two cases subsequent to removal of an acute subdural hematoma. These results that serial ultrasonographic examination of the lateral ventricles through a craniectomy can supplement CT scanning in the evaluation of hydrocephalus and is also useful in evaluating cerebrovascular disease, brain tumors, infection, and head injury.