Verifying complete obliteration of carotid artery-cavernous sinus fistula: role of color Doppler ultrasonography

Paradoxical exacerbation of symptoms with obstruction of the venous outflow after gamma knife radiosurgery for treatment of a dural arteriovenous fistula of the cavernous sinus

A 59-year-old female presented with progressive right proptosis, chemosis and ocular pain. An imaging work-up including conventional catheter angiography showed a right-sided dural arteriovenous fistula of the cavernous sinus, which drained into the right superior petrosal sinus, right superior ophthalmic vein, and right inferior ophthalmic vein, and cortical venous reflux was seen via the right petrosal vein in the right posterior fossa. After failure of transvenous embolization, the patient underwent Gamma Knife radiosurgery (GKRS). At one month after GKRS, she developed increasing ocular pain and occipital headache. Repeat angiography showed partial obliteration of the fistula and loss of drainage via the superior and inferior ophthalmic veins with severe congestion, resulting in slow flow around the right cerebellar hemisphere. Prompt transarterial embolization relieved the patient's ocular symptoms and headache. We report on a case of paradoxical exacerbation of symptoms resulting from obstruction of the venous outflow after GKRS for treatment of a dural arteriovenous fistula of the cavernous sinus.

Diagnosis and follow-up study of carotid cavernous fistulas with color Doppler ultrasonography: analysis of 33 cases

OBJECTIVE

The purpose of this study was to observe image characteristics and hemodynamic changes of carotid-cavernous sinus fistulas (CCFs) and to evaluate the efficacy of interventional treatment for CCFs by color Doppler ultrasonography (CDUS).

METHODS

Thirty-three patients with suspected CCFs were studied with CDUS. Forty-six volunteers took part in this study as controls. Scanning was performed through temporal, orbital, and occipital windows to measure the blood flow parameters of the internal carotid artery (ICA) and related vessels. All results were confirmed by cerebral angiography. Nineteen patients were followed after interventional treatment.

RESULTS

Thirty-two patients (97%) were found to have CCFs by CDUS. Irregular mosaic flashes were observed in the cavernous sinus region, the cross-section areas of which were significantly larger than those of the normal intracranial ICA (1.7-5.2 versus 0.2-0.5 cm(2); P < .01). A lower resistive index of the ICA in the affected side was revealed with spectral analysis of relevant vessels. The peak velocity of vessels distal to the fistula was significantly lower than that of the healthy side and control group (P < .05). Superior ophthalmic veins had a reversed arterialized flow pattern with a mean velocity of 34.5 cm/s and an average resistive index +/- SD of 0.31 +/- 0.08. In follow-up study, the mosaic flashes and turbulence flow disappeared in 14 patients and remained in 5 after the interventional operation.

CONCLUSIONS

Combined with the direct sign of an irregular mosaic flash in the cavernous sinus region, hemodynamic changes in relevant branch vessels, and a reversed arterialized flow pattern in superior ophthalmic veins, CDUS has great value in confirming diagnosis and follow-up study of CCFs.

Diagnosis of intracranial dural arteriovenous fistulas by carotid duplex sonography

OBJECTIVE

To validate carotid duplex sonography (CDS) in diagnosis of intracranial dural arteriovenous fistulas (AVFs) against the standard of cerebral catheter angiography.

METHODS

We investigated 35 patients with dural AVFs and 64 patients without dural AVFs confirmed by the catheter angiographic studies. Twenty CDS parameters in 4 categories, including resistive index (RI), flow volume, peak systolic velocity, and end-diastolic velocity, were evaluated. Abnormal CDS findings were defined as the data above 95th percentile or below 5th percentile values from 180 control subjects. We determined the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in each CDS parameter.

RESULTS

The parameter of RI of the external carotid artery (ECA; cutoff points: right, 0.72; left, 0.71) yielded the highest sensitivity (74%), specificity (89%), positive predictive value (79%), negative predictive value (86%), and accuracy (84%) for predicting dural AVFs. All other ECA-related parameters yielded sensitivity lower than 70%, and those related to the internal carotid artery were lower than 30%. The sensitivity values for the parameter of RI of the ECA in different locations of dural AVFs were 54% (7 of 13 patients) in cavernous sinus dural AVFs and 86% (19 of 22 patients) in non-cavernous sinus dural AVFs (P = .05).

CONCLUSIONS

The RI of the ECA is the best CDS parameter for predicting intracranial dural AVFs. Carotid duplex sonography can be used as the initial screening tool for diagnosis in patients having symptoms related to dural AVFs.

Carotid and transcranial color-coded duplex sonography in different types of carotid-cavernous fistula

BACKGROUND AND PURPOSE

Patients with carotid-cavernous fistula (CCF) may undergo direct or indirect shunting. Ultrasonography has value that is complementary to angiography in the assessment and follow-up of these patients. The aim of this study was to characterize findings provided by carotid duplex sonography (CDS) and transcranial color-coded duplex sonography (TCCD) in patients with different types of CCF.

METHODS

CDS and TCCD were independently performed by technologists and neurologists. Digital subtraction or MR angiography was interpreted by a neuroradiologist. Ultrasonographic studies were categorized into 4 types: I, direct shunting only; II, direct shunting with a carotid aneurysm; III, indirect shunting only; and IV, mixed (direct and indirect) shunting. In addition to carotid and intracranial flow velocities, volume, and pulsatility, other direct and indirect ultrasound signs of shunting were evaluated. The direct sign of CCF was a mosaic flash detected by TCCD. Alteration of hemodynamic parameters on CDS and demonstration of draining veins with the use of TCCD were considered indirect signs.

RESULTS

Fifteen patients (8 men, 7 women) were included in the study. According to angiographic results, patients in ultrasonographic classification types I (n=7) and II (n=3) corresponded to type A of Barrow's classification. Patients with type III (n=8) were Barrow's type C. Type IV (n=1) had a combination of Barrow's types A and C. On ultrasound, both direct and indirect signs were seen in types I, II, and IV CCF. The presence of a 2-colored oval mass divided by a zone of separation without turbulence differentiated type I from type II CCF. All patients with type III CCF had indirect signs, and only 1 patient had direct signs on TCCD. Abnormal TCCD findings were most commonly seen through the transorbital window (100%), followed by the transtemporal window (63%) and transforaminal window (40%).

CONCLUSIONS

If only indirect ultrasonographic signs of CCF are present, TCCD can be used to predict an indirect CCF type on the basis of the origin of the fistula. With direct communication between carotid artery and cavernous sinus, both direct and indirect ultrasonographic signs can be found. The combination of CDS/TCCD may provide a noninvasive and reliable way to classify patients with CCF.