Sonographic Harmonic Grey Scale Imaging of Brain Perfusion: Scope of a New Method Demonstrated in Selected Cases

Abstract AIM: Transient response harmonic transcranial sonography is a new bed-side technique which provides information on brain tissue perfusion. This paper demonstrates the scope of perfusion transcranial sonography (p-TCS). METHODS: P-TCS was performed in an axial insonation plane through the thalamus and third ventricle in a case with Moyamoya disease and a patient with bilateral thalamic oedema due to thrombosis of the internal cerebral veins, and compared to results in 10 healthy controls. Signal increase induced by a bolus of an echo-contrast agent (Optison™) was quantified in regions of interest (ROI) in the thalamus (TH), lentiform nucleus (LN) and the cerebral white matter (WM). RESULTS: In Moyamoya disease p-TCS could demonstrate a decreased perfusion in the WM and LN as a result of bilateral, high-grade stenoses of the intracranial part of the internal carotid artery. Peak intensity was increased in the TH due to collateral cross-over flow from the vertebrobasilar system. TH perfusion was decreased in thrombosis of the internal cerebral vein thrombosis with normal LN perfusion. The extention of the thalamic oedema into the white matter could also be demonstrated by decreased perfusion in the adjacent WM. ROI ratios of different tissues proved helpful in quantifying the perfusion results. CONCLUSION: P-TCS is a new, promising technique that can supply information on pathological brain tissue perfusion at the patient's bed-side.