PAPER Second harmonic imaging: a new ultrasound technique to assess human brain tumour perfusion

Background: Second harmonic imaging is a new ultrasound technique that allows evaluation of brain tissue perfusion after application of an ultrasound contrast agent. Objective: To evaluate the potential of this technique for the assessment of abnormal echo contrast characteristics of different brain tumours. Methods: 27 patients with brain tumours were studied. These were divided into four groups: gliomas, WHO grade III–IV (n = 6); meningiomas (n = 9); metastases (n = 5); and others (n = 7). Patients were examined by second harmonic imaging in a transverse axial insonation plane using the transtemporal approach. Following intravenous administration of 4 g (400 mg/ml) of a galactose based echo con-trast agent, 62 time triggered images (one image per 2.5 seconds) were recorded and analysed off-line. Time–intensity curves of two regions of interest (tumour tissue and healthy brain tissue), includin