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Cranial dural fistulae are rare; when they occur, it is usually difficult to detect them at an early stage. With a view to the question of possible progress in diagnosis we now report on seven patients with lateral dural fistulae fed by branches of the external carotid artery. The examination was carried out before selective arteriography using cw-Doppler sonography and colour coded duplex sonography in combination. Sonographic criteria for detection of hyperperfusion take account of flow velocity as well as pulsatility. In all cases hyperperfusion of the external carotid artery was detected. In most of these cases pathologic findings were also observed at the occipital artery, and more rarely in the contralateral external carotid artery or the ipsilateral vertebral artery, in addition. A possible source of error arising from confusion of blood vessels was present with the cw-Doppler sonography, but not for colour coded duplex sonography. Therefore, cranial dural fistulae characterized by a high shunt volume can be diagnosed correctly by indirect Doppler sonographic criteria using cw-Doppler and duplex sonography. Direct visualization of the fistula and its nidus requires additional selective arteriography, in the course of which endovascular embolization may be performed.

The aim of this study was to assess the current value of extracranial continuous wave (cw) Doppler sonography in routine use as compared to color-coded duplex sonography. For this purpose, 500 carotid and 500 vertebral arteries were examined by a user experienced in both methods. The error rate of Doppler sonography was determined only when the methods allowed a clear decision to be made about the status of the vessel (normal findings including common variants, stenosis, and occlusion). In 85.4% of the carotid arteries and 88% of the vertebral arteries, the Doppler findings fulfilled the diagnostic differentiation unequivocally. For these cases, false findings were obtained in 1.9% of the carotid arteries and 0.2% of the vertebral arteries. Accordingly, a clear Doppler sonographic finding, normal or pathologic, is still of large diagnostic value. However, ambiguous or uncertain findings requiring further diagnostic workup are not uncommon. Thus, the sole use of cw Doppler sonography is no longer sufficient in a stroke center but still retains its utility in the practitioner's office.

Spontaneous or traumatic arteriovenous fistulae between vertebral artery and the surrounding venous plexus may cause vertebrobasilar hypoperfusion by steal effects. We report on a 71-year-old man presenting with vertigo. Duplex sonography revealed a vertebral arteriovenous fistula at the C4/5 level with the typical perivascular color Doppler artifact and hyperperfusion in the supplying arteries and draining veins. Angiography confirmed the findings; the consequently performed endovascular embolization using platin coils and silicon balloon removed the symptoms immediately. Ultrasonographic follow-up examinations within 5 months demonstrated the success of therapy showing only low-flow fistula yet. This case demonstrates that early detection of a vertebral arteriovenous fistula by duplex sonography is highly beneficial because efficient treatment modalities are available.

Cranial dural fistulae are rare; when they occur, it is usually difficult to detect them at an early stage. With a view to the question of possible progress in diagnosis we now report on seven patients with lateral dural fistulae fed by branches of the external carotid artery. The examination was carried out before selective arteriography using cw-Doppler sonography and colour coded duplex sonography in combination. Sonographic criteria for detection of hyperperfusion take account of flow velocity as well as pulsatility. In all cases hyperperfusion of the external carotid artery was detected. In most of these cases pathologic findings were also observed at the occipital artery, and more rarely in the contralateral external carotid artery or the ipsilateral vertebral artery, in addition. A possible source of error arising from confusion of blood vessels was present with the cw-Doppler sonography, but not for colour coded duplex sonography. Therefore, cranial dural fistulae characterized by a high shunt volume can be diagnosed correctly by indirect Doppler sonographic criteria using cw-Doppler and duplex sonography. Direct visualization of the fistula and its nidus requires additional selective arteriography, in the course of which endovascular embolization may be performed.