Noninvasive assessment of intracranial fistulas and other small arteriovenous malformations

Comparison of MRI, MRA, and DSA for Detection of Cerebral Arteriovenous Malformations in Hereditary Hemorrhagic Telangiectasia

BACKGROUND AND PURPOSE

Patients with hereditary hemorrhagic telangiectasia (HHT) have a high prevalence of brain vascular malformations, putting them at risk for brain hemorrhage and other complications. Our aim was to evaluate the relative utility of MR imaging and MRA compared with DSA in detecting cerebral AVMs in the HHT population.

MATERIALS AND METHODS

Of 343 consecutive patients evaluated at the University of California, San Francisco HTT Center of Excellence, 63 met the study inclusion criteria: definite or probable hereditary hemorrhagic telangiectasia defined by meeting at least 2 Curacao criteria or positive genetic testing, as well as having at least 1 brain MR imaging and 1 DSA. MRIs were retrospectively reviewed, and the number of AVMs identified was compared with the number of AVMs identified on DSA.

RESULTS

Of 63 patients, 45 (71%) had AVMs on DSA with a total of 92 AVMs identified. Of those, 24 (26%) were seen only on DSA; 68 (74%), on both DSA and MR imaging; and 5 additional lesions were seen only on MR imaging. Of the 92 lesions confirmed on DSA, 49 (53.3%) were seen on the 3D-T1 postgadolinium sequence, 52 (56.5%) were seen on the 2D-T1 postgadolinium sequence, 35 (38.0%) were seen on the SWI sequence, 24 (26.1%) were seen on T2 sequence, and 25 (27.2%) were seen on MRA. The sensitivity and specificity of MR imaging as a whole in detecting AVMs then confirmed on DSA were 80.0% and 94.4%, respectively, and the positive and negative predictive values were 97.3% and 65.4%, respectively.

CONCLUSIONS

This study reinforces the use of MR imaging as a primary screening tool for cerebral AVMs in patients with hereditary hemorrhagic telangiectasia and suggests that 3D-T1 postgadolinium and 2D-T1 postgadolinium performed at 3T are the highest yield sequences.

Transcranial Doppler study of cerebral arteriovenous malformations after gamma knife radiosurgery

The aim of this study was to evaluate the clinical value of the Transcranial Doppler (TCD) in follow-up examinations after gamma knife radiosurgery (GKS) for arteriovenous malformations (AVM). We performed TCD after GKS in 18 patients who had cerebral AVMs to evaluate the hemodynamic effects of the procedure. Ten patients underwent TCD within 12 months after GKS, and eight between 12 and 24 months. The mean blood velocity (Vm) and pulsatility index (PI) were primarily analyzed in the feeding arteries (FAs) and non-FAs. Fifteen healthy volunteers served as control patients. The Vm values in the FAs after GKS ranged from 31 cm/s to 90 cm/s, with PI values ranging from 0.48 to 1.03. The Vm values in the comparable normal arteries ranged from 28 cm/s to 87 cm/s, and the PI values in these arteries ranged from 0.62 to 1.02. The Vm and PI values in every FA in all patients were normal compared to the values in the non-FAs (p=0.67 and 0.38, respectively). Our results suggest that AVM vessels with high Vm and low PI values return to normal as the nidus of the AVM is obliterated after GKS. Although there was a trend toward a reduction of the Vm values after obliteration, this trend was not significant, except when the < 12 month subgroup was compared to the 12-24 month subgroup. In our limited study, TDC proved to be a reliable, safe and non-invasive method to monitor the outcome of GKS for cerebral AVMs.

[Carotido-cavernous fistula after traumatic brain injury: an unusual vascular complication]

The authors reported the case of a young man who suffered a cranial traumatism and showed neurological, ophthalmic and orbital signs with orbital bruit, cranial nerve palsy and chemosis while he was in the intensive care unit. Further examinations of imagery made it possible to highlight a high-flow carotid-cavernous fistula which was the origin of these symptoms and which was successfully treated by endovascular way. The aim of this article is to remind the reader of the characteristics of this pathology, in terms of epidemiology, physiopathology, clinical and paraclinical presentation, and therapeutic care.

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.

The benign course of carotid-cavernous fistula in a child

Carotid-cavernous fistulas (CCF) are reported very rarely in childhood and their clinical course and prognosis are uncertain. We report a 9-year-old boy presented with left eye swelling, neck pain and headache. The MRI findings suggested a CCF with enlarged left superior ophthalmic vein. Ocular Doppler ultrasonography revealed enlarged left superior ophthalmic vein, and arterialization of Doppler wave form. The cerebral angiogram showed normal anatomy. Control Doppler examination findings supported the diagnosis of closure of fistula. The clinical and radiological findings of this unusual presentation are discussed.

Hemodynamic changes in arterial feeders and draining veins during embolotherapy of arteriovenous malformations: an experimental study in a swine model

OBJECTIVE

Transcatheter assessment of changes in draining vein (DV) flow velocity has been proposed recently as a potentially useful procedure for hemodynamic monitoring of the progression of embolotherapy in cerebral arteriovenous malformations (AVMs). We compared and contrasted changes in hemodynamic parameters of arterial feeders (AFs) and DVs during experimental AVM embolotherapy.

METHODS

Carotid-jugular fistula-type AVM models were surgically created in eight swine. Pre- and postembolization transcatheter mean AF and DV pressures, DV-time average spectral peak velocity, and AF and DV pulsatility indices were assessed. An expression, the peak systolic velocity minus end-diastolic velocity (Vs - Ved), was also used in evaluating the transvenous Doppler spectra. Pre- and postembolization hemodynamic parameters were compared statistically.

RESULTS

Pre-embolization DV flow was pulsatile (Vs - Ved, 12 +/- 4.8 cm/s), with a mean DV velocity of 39.3 +/- 11.4 cm per second. Postembolization, this changed to a less/nonpulsatile pattern (Vs - Ved, 5.4 +/- 2.7 cm/s; P = 0.0035) with a lower mean DV-average spectral peak velocity of 7.0 +/- 3.1 cm per second (P = 0.0001). The mean DV pressure was also reduced from 52.0 +/- 8.2 to 45.5 +/- 8.7 mm Hg (P = 0.0023). The mean AF pressure increased from a mean of 79.5 +/- 15.5 to 96.8 +/- 16.2 mm Hg (P = 0.0004). The DV pulsatility index values also increased from a mean of 0.3 +/- 0.2 to 1.1 +/- 0.5 (P = 0.0003). Periembolization objective hemodynamic changes were detected in the DVs earlier than were the visually subjective angiographic changes observed within the nidus.

CONCLUSION

This preliminary study indicates that transvenous assessment of average spectral peak velocity and wave pattern (Vs - Ved) may be useful in the hemodynamic evaluation of AVM shunting. The convergence of these two parameters to a range less than 10 cm per second after nidus embolization may afford a theoretical advantage over AF pressure measurements when used for objective and quantitative monitoring of endovascular embolotherapy.

Diagnosis and follow-up of carotid-cavernous fistulas by carotid duplex sonography and transcranial color Doppler imaging

To investigate the suitability of extracranial carotid duplex (ECD) and transcranial color Doppler imaging (TCDI) in the diagnosis and follow-up of treatment in patients with carotid-cavernous fistulas (CCF), combined ECD and TCDI examinations were studied in seven patients with traumatic CCF. According to angiography, four patients had direct CCF, two indirect CCF and one both direct and indirect CCF. In ECD, hemodynamic parameters of the feeding artery showed an abnormally increased flow volume and decreased resistivity indices in five direct CCFs from the internal carotid artery and one indirect CCF from the external carotid artery. Direct visualization of the CCF was achieved in patients with direct CCF only, and revealed itself as a heterogeneous mosaic flash resulting from high flow velocities and turbulence. Patterns of venous drainage were detected via the transorbital and transforaminal windows in seven and five patients (four direct and one indirect CCF patients), respectively. These abnormal findings were improved or even normalized after successful treatment. In conclusion, combined ECD and TCDI examinations appear to be useful for the diagnosis and follow-up of CCF.

Early discovery of a traumatic carotid-cavernous sinus fistula by jugular venous oxygen saturation monitoring. Case report

This report describes the early diagnosis, due to an acute increase of jugular venous oxygen saturation occurring 20 hours after trauma, of a traumatic carotid-cavernous sinus fistula after severe head injury. Hyperemia in severe head injury should be treated only after an intracerebral arteriovenous communication has been excluded.