The Application Of Cerebral Blood Volume Software In Assessing The Cerebral Blood Volume Comparative Study On The Clinical Manifestations Before And After BOTwith Hypotension

Background: Clinically, in the treatment of cerebrovascular disease, such as traumatic internal carotid artery(ICA) cavernous Sinus Fistula (Carotid-cavernous Sinus Fistula, CCF) and internal carotid artery pseudoaneurysm, Sometimes it need to occlude the lesions and internal carotid artery at the same time. Therefore it must be considered that insufficient blood supply, even disability and death may occur for that the internal carotid artery blood flow is temporary or permanent blocking. Therefore it need to determine the brain’tolerrance of occluding the internal carotid artery to avoid irreversible brain damage, and make the corresponding processing to increase the patients’tolerance of occluding the ICA for who didn’t tolerate the occluding, such as intracranial vascular bypass surgery, oppression, training methods and so on. Then according to the results make a selective decision. So the susceptibility of effective judgment method for clinical guidance and special significance is obvious. There are many auxiliary methods to evaluate whether ICA can be occluded. the most commonly used is the balloon occlusion test. BOT is used to assess the tolerance of vascular occlusion pre-operation. Clinical judgment for BOT negative patients, however, there are still some patients after permanent occlusion of ICA will occur ischemic complications. Less serious cases crippled, the person serious will lead to large area cerebral infarction and death. Cloughesy TF reported5%～20%incidence of cerebral infarction, and data showed that patients with internal carotid artery or ligation of common carotid arteries ligation side even to the contralateral side of the incidence of ischemic stroke was14%～20%, and25times than that of normal people. In addition, some patients with BOT shows poor compensatory, but for some reason did not appear any complications after permanent occlusion of internal carotid. So only judging from clinical manifestation, conventional methods of BOT is not accurate enough. Ma Lian-ting treated528cases of traumatic internal carotid artery cavernous sinus fistula in our hospital and21%of which need to occluded internal carotid artery. At the same time, due to strictly adhere to the BOT with hypotension(mean arterial pressure drop to around70mmHg and high blood pressure patients drop to two-thirds of the original blood pressure levels), only2cases with mild symptoms of nerve function loss (recovery) after treatment, all cured. There is no death and disability. Therefore, we regard BOT as the gold standard for evaluating whether ICA can be occluded. Blood pressure BOT as a gold standard mainly from clinical judgment and lack of objective quantitative or semi-quantitative objective basis.At present, along with the popularity of angiography system equipped with a flat-panel detector. Flat CT (flat panel detector computer tomography, FDCT) as a representative for the advanced features get more and more widely used in clinical application. Through this technology, we can get interior parenchymal CT images in the tube. It is very useful for physician to determine intraoperative hemorrhage complication and postoperative evaluation of stent implantation. With the progress of technology, through FDCT already we can get whole brain cerebral blood volume (cerebral blood volume, CBV). The application value of this method has been confirmed in the animal experiments, and began at the center of the minority of clinical research at home and abroad. But the inspection method hasn’t been widely used for its accuracy has to be confirmed further. FDCT-CBV is a new kind of hemodynamic evaluation technology that obtained from the post-processing software developed by Siemens company for its big tablet DSA machine. It can real-time monitoring of cerebral hemodynamic changes in catheter indoor. Its basic principle is the contrast agent through the brain will cause the change of CT density and the dynamic scanning method for contrast agents for the first time by the time when the brain tissue density curve. According to a certain mathematical model calculation can obtain CBV that as measurement index of cerebral blood volume, and reflect the hemodynamic changes in the body compensatory. CBV decreased often prompted local brain microcirculation. Also the scholar thinks, CBV absolute value change is the most accurate parameters reflect the cerebral infarction. Schramm’research indicated that CBV changes combined with CT scan can be used to distinguish ischemic necrosis half dark zone and the core of the infarction area. If CBV damage range is obvious, at the same time, CT scan has visible low-density lesions, we can infer that the area of the brain can’t restored. Syngo Dyna PBV Neuro as a perfusion imaging software that can be finished on DSA machine and complete CBV measurement. So it is extremely promising, getting more and more attention of people. Scholars at home and abroad by animal and clinical studies have proved that FDCT-CBV with traditional PCT-CBV results have good consistency. The differences of CBV by two methods are very small. So we think that the CBV that we finished on DSA machine, although can’t reflect the comprehensive information of cerebral perfusion, but for acute ischemic stroke, already can help doctors determine infarction. The biggest advantage of CBV is conducted on DSA machine, so it is hopeful to be an important imaging reference index for developing clinical treatment and evaluating curative effect. On this basis, Aiming to find an objective indicator for Balloon Occlusion Test with hypotension which is the gold standard of occluding internal carotid artery(ICA). The change of mean rCBV that acquired from FDCT-CBV was compared with the change of clinical manifestations before and after Ballon Occlusion Test with hypotension and its consistency was analyzed.Objective: To discuss the application of Cerebral Blood Volume Software in assessing the CBV comparative study on the clinical manifestations before and after BOT with hypotension. Aiming to find an objective indicator for Balloon Occlusion Test with hypotension which is the gold standard of occluding internal carotid artery(ICA).Method:In October2012to October2013, patients conformed to the standard in our department through the whole brain blood vessels (6) the entire stage (arterial blood capillary-vein-venous sinus) angiography. Specific criteria included: older than18years old; patients who need underwent BOT to evaluate whether a permanent ICA occlusion can be performed:(1) intractable aneurysms or false aneurysm that can’t chip or failed to interventional therapy, need to block parent artery trunk;(2) skull base surgery or interface treatment that may cause the ICA or basal artery rupture, need to block the artery;(3) head and neck tumor surgery, lesions involving or package around the major cerebral arteries;(4) internal carotid artery cavernous sinus fistula treated may affect the ICA;(5) arterial hemorrhage caused by trauma, infection and tumor; Agree to sign the informed consent.(1) After the perfect preoperative preparation, the patients was placed in supine position and received intravenous sedation plus local anesthesia. Seldinger arterial puncture technique was then used by placing an8-French sheath into right femoral artery and a5-French sheath into left femoral artery. Next, A CBV map was acquired using the same FDCT system15minutes before the test. This CBV map generation consisted of dual3D image acquisition steps. For it, a3D mask image was acquired first and at the same time,60ml CM(Iopromide Injection,370mgI/ml) was injected intravenously by a power injector (250psi) at the rate of4ml/s. To ensure that the contrast enhancement in the brain tissue has reached the steady state, the second3D image acquisition started manually by monitoring the angiography using2frames/s until superior sagittal sinus filling was observed. During the second3D image acquisition, the C-arm rotated for200°in8s, with angle increment of0.5°. As an output, a total number of397projection images were generated with X-ray dose of0.36μGy/frame. The post-processing was performed using commercially available software (syngo DynaPBV Neuro, Siemens Healthcare, Germany).(2) Next BOT with hypotension: an8-French guiding catheter was advanced to the artery to be tested under fluoroscopic guidance. A non-detachable balloon (MagicB2, Balt, Montmorency, France) was positioned and inflated to block blood flowing through the artery. Complete occlusion of the carotid artery was visually verified by manual injection of contrast medium through the guiding catheter. A5-French angiographic catheter was inserted on the other side ICA or vertebral artery to assess collateral supply from the contra-lateral carotid arteries. At the same time mean arterial pressure was lowered to70-80mmHg for patients without history of hypertension, and to two thirds of the baseline for patient with hypertension.15minutes later CBV maps acquired using the same method as above (if BOT’result is positive, the balloon was deflated immediately to restore the normal blood flow and5minutes later CBV maps acquired). The balloon was left in place for approximately30minutes, during which the patient was neurologically monitored. Complete occlusion of the carotid artery was visually verified by manual injection of contrast medium through the guiding catheter before the test is over. In the cases that collateral supply from the contra-lateral carotid arteries or vertebrobasilar system was insufficient such that changes in sensory function were detected, the test was considered positive. A test is considered negative or passed if no neurologic deficit could be observed.Three anatomically characteristic planes were selected crossing frontal, parietal lobes and basal ganglia regions. Circular ROIs with area of2cm2were manually defined on axial planes to cover the ICA territories of both hemispheres, in an attempt to have major vessels excluded. Spatially averaged CBV value in the ROIs before and during the BOT were extracted and compared. Relative CBV (rCBV) values were then calculated by:rCBV=CBV_affected/CBV_unaffected, where CBV affected and CBV unaffected were the mean CBV value extracted from the ROIs at affected and unaffected hemispheres, respectively. The changes of rCBV and manifestation were compared.Result: Each patient underwent one ICA BOT and two CBV image acquisitions. There were no procedural complications detected. It can be seen that before the BOT, for all the10patients, a stable symmetry of perfusion could be found for two hemispheres with averaged rCBV values0.98-/+0.03in plane1,1.03-/+0.07in plane2, and1.01-/+0.08in plane3, where all the calculated rCBV were close to1.00.10patients were involved in this study, of which, no ischemic complications were recognized in8patients. Including6cases of CCF,1case of Giant aneurysm on ICA cavernous sinus segment, and1case of CCF and pseudoaneurysm. Good perfusion symmetry was detected with averaged rCBV0.96±0.05before BOT with hypotension and averaged rCBV1.02±0.06during BOT with hypotension; In those8patients,1patient underwent permanent ICA occlusion with a detachable balloon without acute or delayed neurologic deficit perceived. The others underwent nidus embolization with coils with keeping ICA unobstructed and got well recovered. Two patients failed to tolerate the BOT test with hypotension that developed in disturbance of consciousness and the contralateral limb hemiplegia. CBVs from the affected hemisphere were significantly lower than those from the unaffected hemisphere in the corresponding regions with mean rCBV reduction close to24%and21%.2patients underwent indus embolization with coils with keeping ICA unobstructed and got well recovered.Conclusion CBV maps have a good consistency with clinical manifestations before and after balloon occlusion test with hypotension. It can be an objective indicator for the gold standard of occluding ICA.