The Position and Role of Four-Dimensional Computed Tomography Angiography in the Diagnosis and Treatment of Spinal Arteriovenous Fistulas.

BACKGROUND: Localization of the arteriovenous fistula (AVF) is a crucial step in the diagnosis and treatment of spinal vascular malformations (VMs). Noninvasive angiographic techniques such as dynamic magnetic resonance angiography and three-dimensional computed tomography angiography (CTA) have been used as standard modalities to localize AVF. With the increasing prevalence of high-specification computed tomography scanners, four-dimensional (4D) CTA is being increasingly used in the evaluation of cerebrovascular disorders. However, application of 4D-CTA in spinal lesions has been limited. The position and role of 4D-CTA, among various modalities, in the evaluation of spinal VMs has not been elucidated. METHODS: We retrospectively review our clinical experience with 4D-CTA used for spinal AVFs. 4D-CTA images were acquired in 10 cases of spinal VMs consisting of 8 dural/epidural AVFs and 2 perimedullary AVFs. Imaging findings of 4D-CTA and digital subtraction angiography were reviewed to validate the usefulness of 4D-CTA. RESULTS: In 9 of 10 cases, 4D-CTA accurately localized the AVF. The scan visualized direction of flow in the perimedullary veins in all cases. Regarding perimedullary AVFs, 4D-CTA showed dynamic images of feeding arteries, AVF, and perimedullary drainage. Information provided by 4D-CTA was beneficial as a reference in subsequent DSA. CONCLUSIONS: In the diagnostic process of spinal VMs, the position of 4D-CTA is the third choice for noninvasive angiography, after dynamic MRA and three-dimensional CTA. However, the role of 4D-CTA might be decisive in difficult-to-find spinal dural AVFs. We believe that this novel imaging technique can be applied in spinal VMs.

Comparison of dual protection and distal filter protection as a distal embolic protection method during carotid artery stenting: a single-center carotid artery stenting experience.

There are several protection methods used to prevent distal embolism during carotid artery stenting (CAS). The aim of this study was to compare the dual protection method (proximal balloon and distal filter protection) with the distal filter protection during CAS performed at a single center. Between April 2008 and November 2013, 78 consecutive patients with internal carotid artery stenosis were treated with CAS at Istukaichi Memorial Hospital. Twenty-four consecutive patients were treated with CAS using distal filter protection (distal filter protection group), and 54 consecutive patients were treated with CAS using dual protection with a proximal balloon and distal filter protection (dual protection group). We examined the hyperintensity lesions on diffusion-weighted imaging (DWI) and perioperative complications after CAS. All stenotic lesions were successfully dilated. DWI showed hyperintensity lesions among 54.2 % (13/24 patients) in the distal filter protection group and in 27.8 % (15/54 patients) in the dual protection group (p = 0.024). The average number of hyperintensity lesions on DWI was 1.75 (range, 0 to 6) in the distal filter protection group and 0.59 (range, 0 to 5) in the dual protection group (p = 0.0087). Postprocedural persistent ischemic complications occurred in 4.2 % (1/24 patients) in the distal filter protection group and 3.7 % (2/54 patients) in the dual protection group (p = 0.67). In this study, the dual protection method reduced the number of hyperintensity lesions seen on DWI when compared with the distal filter protection method when used for distal embolic protection during CAS.

Carotid artery stenting using the proximal or dual protection method for near occlusion of the cervical internal carotid artery.

The treatment for patients with near occlusion of the cervical internal carotid artery (ICA) is controversial. The aim of this study was to examine the results of carotid artery stenting (CAS) as a surgical treatment for ICA near occlusion. Between April 2008 and September 2012, 14 patients (all men; mean age, 75.4 years) with ICA near occlusion were treated with CAS. This represents 5.2% of a total of 267 patients treated with CAS during the study period. All patients were treated with CAS using an embolic protection device. The proximal balloon protection method was performed in five patients, and the dual protection method using a proximal balloon and distal filter protection was used in nine patients. We examined the change of stenotic lesion, hyperintensity spot in diffusion-weighted imaging (DWI), and perioperative complications after CAS. All near occlusions were successfully dilated. Among 2 of 14 patients, DWI showed 1 and 4 hyperintensity spots. Transient and persistent complications, including neurological deficits, did not occur in any patients. In this small number of cases, CAS using the proximal or dual embolic protection method seems to be a safe and beneficial treatment for ICA near occlusion.

Application of 4D-CTA using 320-row area detector computed tomography on spinal arteriovenous fistulae: initial experience.

Time-resolved computed tomography angiography (4D-CTA) using a 320-row area detector CT scanner has recently been applied in the evaluation of cranial vascular disorders. However, application of 4D-CTA to spinal vascular disorder evaluation has never before been described. The authors herein report their initial experience of 4D-CTA in the evaluation of spinal arteriovenous fistulas (AVFs) and compare this novel modality with other imaging modalities. Four consecutive patients with spinal AVF underwent time-resolved contrast-enhanced magnetic resonance angiography (trMRA), 4D-CTA, and selective catheter angiography (CA). In 4D-CTA, volume data was transformed into 3D volume-rendered images and maximum intensity projection. These images were also evaluated by time-resolved serial phases. Then, images of each modality were compared, focusing on the detection of perimedullary draining veins and the prediction of AVF location and drainage flow direction. All modalities successfully detected perimedullary draining veins in all cases. Location of the AVF was detected in all cases by CA. trMRA and 4D-CTA detected the AVF in three out of the four cases. With regard to flow direction, while 4D-CTA successfully depicted ascending or descending drainage flow in the spinal canal, CA failed to detect the flow direction in one case while trMRA failed in two cases. In the case with epidural AVF, 4D-CTA was the only technique to detect the flow direction of perimedullary drainage. Although this is only an initial experience of the application of 4D-CTA to spinal vascular diseases, 4D-CTA was capable of detecting the dynamic vascular flow of spinal AVFs. The authors believe that 4D-CTA can be a useful option in the evaluation of spinal AVFs.

Endovascular stenting of symptomatic innominate artery stenosis under distal balloon protection of the internal carotid and vertebral artery for cerebral protection: a technical case report.

The use of cerebral protection devices in endovascular treatment for innominate artery (IA) stenosis is not well established. We describe a novel technique for cerebral protection during endovascular stenting of symptomatic IA stenosis. An 82-year-old man presented with acutely scattered brain infarction by artery-to-artery embolism due to IA stenosis. Endovascular treatment for symptomatic IA stenosis was planned to prevent recurrent attacks. Endovascular stenting for IA stenosis via the right femoral artery approach was performed under simultaneous distal balloon protection of the right internal carotid artery (ICA) and vertebral artery (VA) via the right brachial artery approach. Successful treatment of symptomatic IA stenosis was achieved with no complications. The technique with simultaneous distal balloon protection of the ICA and VA provided excellent cerebral protection in stenting of IA stenosis.

Transient headache related to enlargement of the contralateral vertebral artery after vertebral artery occlusion.

BACKGROUND: Endovascular proximal parent artery occlusion has been performed for VA dissection. We describe a case that presented with headache associated with transient enlargement of contralateral VA after VA occlusion. CASE DESCRIPTION: A 54-year-old man presented with constant occipital headache on the left due to left VA dissection. Proximal parent artery occlusion of the left VA with detachable coils was performed, and the headache disappeared after coil occlusion. However, the patient presented with occipital headache on the right 1 week later. The MRI showed enlargement of the right VA compared with before the procedure. Four weeks later, the right occipital headache disappeared, and MRI showed improvement of enlargement of the right VA. CONCLUSION: The patient might present with right occipital headache related to transient enlargement of contralateral VA after VA occlusion. Careful postoperative neuroradiological examination of the contralateral VA is required because contralateral VA enlargement may be caused by hemodynamic stress after VA occlusion.