Treatment of dural sinus thrombosis by urokinase infusion.

PURPOSETo gain a preliminary understanding of the role of thrombolytic therapy for the thrombosed dural sinus, we retrospectively reviewed our initial experience.METHODSSeven patients, ages 25 to 71, who presented with symptomatic dural sinus thrombosis and who failed a trial of medical therapy were treated with direct infusion of urokinase into the thrombosed sinus. Patients received urokinase doses ranging from 20,000 to 150,000 U/h with a mean infusion time of 163 hours (range 88 to 244 hours).RESULTSPatency of the affected dural sinus was achieved with antegrade flow in all patients. Six patients either improved neurologically over their prethrombolysis state or were healthy after thrombolysis; one of them required angioplasty. The other patient improved after surgical repair of a residual dural arteriovenous fistula. The only complications were an infected femoral access site which resolved after treatment with antibiotics and hematuria which cleared after discontinuation of anticoagulation.CONCLUSIONSThrombolysis of the thrombosed dural sinus shows promise as a safe and efficacious treatment. The results of this study should provide the impetus for further research.     

血管内介入治疗颅内静脉窦血栓形成

目的 探讨血管内介入方法治疗颅内静脉窦血栓形成的疗效和安全性.方法 对27例抗凝治疗无效的颅内静脉窦血栓形成患者行血管内介入治疗,其中19例行局部静脉窦溶栓及机械性破栓治疗,5例行局部静脉窦溶栓、机械性破栓及动脉溶栓治疗,3例行静脉窦支架置入术.结果 23例患者的症状、体征明显改善,其中头痛消失18例,视力改善12例;3例症状无改善,出院前22例患者测脑脊液压力正常,血管造影等检查证实21例患者静脉窦主干通畅,皮层静脉和深静脉恢复正常;3例部分再通,皮层静脉和深静脉部分代偿.结论 血管内介入治疗是颅内静脉窦血栓形成安全、有效的治疗手段.     

Randomized comparison of intra-arterial and intravenous thrombolysis in a canine model of acute basilar artery thrombosis

We compared the rates of recanalization cerebral infarct and hemorrhage between intra-arterial (IA) reteplase and intravenous (IV) alteplase thrombolysis in a canine model of basilar artery thrombosis. Thrombosis was induced by injecting a clot in the basilar artery of 13 anesthetized dogs via superselective catheterization. The animals were randomized in a blinded fashion, 2 h after clot injection and verification of arterial occlusion, to receive IV alteplase 0.9 mg/kg over 60 min and IA placebo, or IA reteplase 0.09 units/kg over 20 min, equivalent to one-half the alteplase dose, and IV placebo. Recanalization was studied for 6 h after treatment with serial angiography; the images were later graded in a blinded fashion. Blinded interpretation of postmortem MRI was performed to assess the presence of brain infarcts and/or hemorrhage. At 3 h after initiation of treatment, partial or complete recanalization was observed in one of six dogs in the IV alteplase group and in five of seven in the IA reteplase group ( P =0.08). At 6 h, no significant difference in partial or complete recanalization was observed between the groups (two of six vs. five of seven; P =0.20). Postmortem MRI revealed infarcts in four of six animals treated with IV alteplase and three of seven treated with IA reteplase ( P =0.4). Intracerebral hemorrhage was more common in the IV alteplase group (four of six vs. none of seven; P =0.02). This study thus suggests that IA thrombolysis affords a recanalization rate similar to that of IV thrombolysis, but with a lower rate of intracerebral hemorrhage.     

多途径联合血管内治疗颅内静脉窦血栓形成

目的研究血管内治疗颅内静脉窦血栓形成的疗效和安全性。方法自2000年10月至2001年10月，12例难治性颅内静脉窦血栓形成患者接受了包括经静脉接触性溶栓、机械性破栓、经颈动脉溶栓和静脉窦内支架置入多途径联合血管内治疗。所有病人均有颅内静脉窦血栓形成的危险因素。术后积极治疗原发病，抗凝治疗6个月。术后随访17～29个月，平均23个月。结果12例患者均接受了经静脉途径溶栓治疗，其中10例患者同时接受联合机械性血栓切割。2例患者同时接受经颈动脉途径溶栓治疗。出院时，所有患者闭塞静脉窦均再通，临床症状改善和颅内压恢复，未出现与血管内治疗相关的并发症。Glasgow评分由术前平均12分，恢复到出院时14分。平均随访23个月，无一例血栓再形成。结论血管内治疗是颅内静脉窦血栓安全、有效的治疗手段。     

MR staging of acute dural sinus thrombosis: correlation with venous pressure measurements and implications for treatment and prognosis.

PURPOSETo correlate parenchymal brain changes, venous sinus pressure measurements, and outcome in 29 patients with acute dural sinus thrombosis.METHODSA retrospective review of 29 patients with angiographically proved acute dural sinus thrombosis was made from January 1989 to December 1993. MR examinations were performed on either a 0.5- or 1.5-T superconductive scanner in multiple planes. Direct dural sinus venography, cerebral angiography, and MR venography were performed. Venous sinus pressure measurements were obtained in 11 of 29 patients.RESULTSWe identified five distinct stages of brain parenchymal changes; each stage correlated with increasing intradural sinus pressure. The pressures measured in this study ranged from 20 to 50 mm Hg. Brain parenchymal changes were reversible up to stage III if thrombolytic treatment was performed. Beyond stage III, there were some residual changes, even after thrombolysis. All stage V patients died.CONCLUSIONAcute dural sinus thrombosis leads to distinct stages of parenchymal changes, the severity of which depends on the degree of venous congestion, which, in turn, is closely related to intradural sinus pressure. As intradural sinus pressure increases, progression from mild parenchymal change to severe cerebral edema and/or hematoma may occur if thrombolysis is delayed.     

Catheter-Directed Thrombolysis with a Continuous Infusion of Low-Dose Urokinase for Non-Acute Deep Venous Thrombosis of the Lower Extremity

Objective

We wanted to evaluate the feasibility of catheter-directed thrombolysis with a continuous infusion of low-dose urokinase for treating non-acute (less than 14 days) deep venous thrombosis of the lower extremity.

Materials and Methods

The clinical data of 110 patients who were treated by catheter-directed thrombolysis with a continuous infusion of low-dose urokinase for lower extremity deep venous thrombosis was analysed. Adjunctive angioplasty or/and stenting was performed for the residual stenosis. Venous recanalization was graded by pre- and post-treatment venography. Follow-up was performed by clinical evaluation and Doppler ultrasound.

Results

A total of 112 limbs with deep venous thrombosis with a mean symptom duration of 22.7 days (range: 15-38 days) were treated with a urokinase infusion (mean: 3.5 million IU) for a mean of 196 hours. After thrombolysis, stent placement was performed in 25 iliac vein lesions and percutaneous angioplasty (PTA) alone was done in five iliac veins. Clinically significant recanalization was achieved in 81% (90 of 112) of the treated limbs; complete recanalization was achieved in 28% (31 of 112) and partial recanalization was achieved in 53% (59 of 112). Minor bleeding occurred in 14 (13%) patients, but none of the patients suffered from major bleeding or symptomatic pulmonary embolism. During follow-up (mean: 15.2 months, range: 3-24 months), the veins were patent in 74 (67%) limbs. Thirty seven limbs (32%) showed progression of the stenosis with luminal narrowing more than 50%, including three with rethrombosis, while one revealed an asymptomatic iliac vein occlusion; 25 limbs (22%) developed mild post-thrombotic syndrome, and none had severe post-thrombotic syndrome. Valvular reflux occurred in 24 (21%) limbs.

Conclusion

Catheter-directed thrombolysis with a continuous infusion of low-dose urokinase combined with adjunctive iliac vein stenting is safe and effective for removal of the clot burden and for restoration of the venous flow in patients with non-acute lower extremity deep venous thrombosis.     

Cerebral Venous Sinus Thrombosis Treated with Vacuum Aspiration Thrombectomy without Thrombolysis: A Descriptive and Retrospective Study of 5 Years’ Experience at a Single Center

PurposeCerebral venous sinus thrombosis (CVST) is a rare but life-threatening condition. Mechanical thrombectomy is a treatment option for patients who deteriorate or do not improve despite anticoagulation treatment or those who have a major contraindication to anticoagulation. The purpose of this study was to describe the authors’ 5 years of experience in treating CVST with vacuum aspiration thrombectomy without thrombolysis.Materials and MethodsFor this retrospective study, data were collected from consecutive patients with CVST who received anticoagulation as initial medical treatment and were treated with vacuum aspiration thrombectomy without thrombolysis. Patients were followed up at 3 months and after 1 year.ResultsThe 9 patients included in the study had a median age of 37 years, and 5 were women. All 9 patients had headaches at presentation; 7 had focal neurologic deficits, and 7 had intracranial hypertension. Risk factors for CVST were identified in 8 patients, and poor prognostic factors were identified in 7 patients. In the 9 patients, 24 CVST locations were treated; complete (70.8%) or partial (29.2%) recanalization was achieved in all CVST locations. No procedure-related complications occurred. One patient died of parenchymal hemorrhagic transformation of CVST and vasogenic edema, 6 hours after the procedure. Two patients required neurosurgical intervention. After 1 year (range, 13–30 months), all 8 surviving patients had good functional outcomes (modified Rankin Scale score 0–2).ConclusionsFor appropriately selected patients with CVST, vacuum aspiration thrombectomy without thrombolysis seemed to be an effective therapy.     

Combined aspiration thrombectomy and continuous intrasinus thrombolysis for cerebral venous sinus thrombosis: technical note and case series

Cerebral venous sinus thrombosis is an uncommon cause of stroke with high morbidity and mortality rates from venous infarction, intracranial hemorrhage, and extensive cerebral edema. Endovascular treatment with various devices has been proposed as a salvage treatment when standard medical treatment with systemic anticoagulation is ineffective, especially in long segment dural sinus thrombosis. We describe our technique of transvenous endovascular aspiration thrombectomy with large bore thrombectomy catheters, followed by placement of microcatheter for local thrombolytic infusion at the site of thrombosis. We report a retrospective study of angiographic and clinical outcome of six consecutive patients treated with this approach. Endovascular aspiration thrombectomy with large bore catheters followed by continuous local thrombolytic infusion appeared to be a safe and effective salvage treatment for selected patients with cerebral dural venous sinus thrombosis refractory to medical treatment.     

Complete recovery after early intraarterial recombinant tissue plasminogen activator thrombolysis of carotid T occlusion

Carotid T occlusion (intracranial carotid bifurcation occlusion with involvement of A1 and M1 segments) is associated with poor outcome. In most cases, treatment with intraarterial thrombolysis within a 6-hour window has been unsuccessful. We describe the case of a 26-year-old woman who presented with severe neurologic deficits (National Institutes of Health Stroke Scale score of 23) secondary to angiographically proved right carotid T occlusion. She was treated with intraarterial infusion of recombinant tissue plasminogen activator that was started less than 3 hours after symptom onset (26 mg administered during 2 hours 15 minutes). Thrombolysis resulted in recanalization of all major intracranial vessels and complete neurologic recovery. Early intraarterial thrombolysis may be effective in the treatment of patients with carotid T occlusion and should be considered for appropriate candidates.     

Relationship between clot location and outcome after basilar artery thrombolysis.

PURPOSETo identify factors that predict survival and good neurologic outcome in patients undergoing basilar artery thrombolysis.METHODSOver a 42-month period, 20 of 22 consecutive patients with angiographic proof of basilar artery thrombosis were treated with local intraarterial urokinase. Brain CT scans, neurologic examinations, symptom duration, clot location, and degree of recanalization were analyzed retrospectively.RESULTSOverall survival was 35% at 3 months. Survival in patients with only distal basilar clot was 71%, while survival in patients with proximal or midbasilar clot was only 15%. At 3 months, 29% of patients with distal basilar clot and 15% of patients with proximal or midbasilar clot had good neurologic outcomes (modified Rankin score of 0 to 2 and Barthel index of 95 to 100). Complete recanalization was achieved in 50% of patients; 60% of those survived and 30% had good neurologic outcomes. Of patients with less than complete recanalization, only 10% survived. Neither duration of symptoms before treatment (range, 1 to 79 hours), age (range, 12 to 83 years), nor neurologic status at the initiation of treatment (Glasgow Coma Scale score range, 3 to 15) predicted outcome. Pretreatment CT findings (positive or negative for related ischemic changes) did not predict outcome or hemorrhagic transformation.CONCLUSIONThe single best predictor of survival after basilar thrombosis and intraarterial thrombolysis was distal clot location. Complete recanalization favored survival. Radiologically evident related infarctions, advanced age, delayed diagnosis, and poor pretreatment neurologic status did not predict poor outcome and therefore should not be considered absolute contraindications for intraarterial thrombolysis in patients with basilar artery thrombosis.     

Rheolytic catheter thrombectomy, balloon angioplasty, and direct recombinant tissue plasminogen activator thrombolysis of dural sinus thrombosis with preexisting hemorrhagic infarctions

We describe the case of a 28-year-old obtunded woman who presented with bilateral anterior parietal lobe cortical hemorrhages associated with thrombosis of the superior sagittal sinus, both transverse and sigmoid sinuses, and multiple cortical veins draining into the sagittal sinus. Initial heparin therapy was not effective. A combination of AngioJet rheolytic catheter thrombectomy, balloon angioplasty, and continuous direct superior sagittal sinus recombinant tissue plasminogen activator infusion led to venous recanalization with a successful clinical outcome, without worsening of the preexisting intracranial hemorrhages.     

重症硬脑膜静脉窦血栓的局部溶栓治疗

目的 研究重症硬脑膜静脉窦血栓的局部溶栓治疗的方法及疗效。方法 总结我院自2000年以来6例重症硬脑膜静脉窦血栓的局部溶栓治疗经验，男4例，女2例，其中4例采用一侧股动脉及对侧股静脉Seldinger穿刺，2例采用股动脉Seldinger穿刺及上矢状窦前1／3穿刺。导管置入一侧颈内动脉及静脉窦血栓处后，于颈内动脉及静脉窦血栓处先后各用尿激酶50万U，以每分钟1万U泵入，再于静脉窦血栓处泵入尿激酶持续溶栓，维持外周血中纤维蛋白原含量1．0～1．5g／L，同时予全身肝素化，维持外周血活化部分凝血活酶时间正常值的2～3倍。结果 本组6例，5例痊愈，颅内压转正常，头痛消失，无神经功能障碍，其中4例数字减影血管造影(DSA)见浅表静脉扩张消失，静脉窦显影正常，1例浅表静脉扩张明显改善，静脉窦显影较前好转；1例好转，颅内压较前降低，头痛好转，DSA见浅表静脉扩张消失，静脉窦显影正常，抗凝治疗1个月后颅内压正常，头痛消失，神经功能恢复正常。结论 重症硬脑膜静脉窦血栓采用动静脉系统联合应用尿激酶局部溶栓治疗是快速、安全、有效的方法，经股静脉途径不易到达静脉窦血栓处者，可以行上矢状窦入路。     

Intra-arterial tirofiban infusion for thromboembolic complication during coil embolization of ruptured intracranial aneurysms

Introduction

Intra-arterial (IA) thrombolytic intervention for acute thrombosis has been challenged due to the risk of bleeding during the endovascular treatment of ruptured aneurysms. We present the results of IA tirofiban infusion for thromboembolic complications during coil embolization in patients with ruptured intracranial aneurysms.

Methods

Thromboembolic events requiring thrombolytic intervention occurred in 39 (10.5%) cases during coil embolization of 372 consecutive ruptured intracranial aneurysms. Maximal aneurysm diameters of 39 patients (mean age, 54.7 ± 13.2 years; 23 female, 16 male) ranged from 2.1 to 13.1 mm (mean, 6.6 ± 3.0 mm). The anterior communicating artery was the most common site (n = 13), followed by the middle cerebral artery (n = 9) and the posterior communicating artery (n = 7). In this series, we used intracranial stents in 10 patients during the procedure. Superselective IA tirofiban infusion through a microcatheter was performed to resolve thrombi and emboli. We assessed the efficacy and safety of IA tirofiban infusion in patients with ruptured aneurysms.

Results

Intraarterially administered tirofiban doses ranged from 0.25 to 1.25 mg (mean, 0.71 ± 0.26 mg). Effective thrombolysis or recanalization was achieved in 34 patients (87.2%), and three patients (7.7%) suffered distal migration of clots with partial recanalization. The rest (5.1%) had no recanalization. Nonconsequent intracerebral hemorrhage occurred in two patients (5.1%) after the procedure. Thromboemboli-related cerebral infarction developed in eight patients, and only two patients remained infarction related disabilities.

Conclusion

IA tirofiban infusion seems to be efficacious and safe for thrombolysis during coil embolization in patients with ruptured intracranial aneurysms.     

Local intraarterial fibrinolysis of thromboemboli occurring during endovascular treatment of intracerebral aneurysm: a comparison of anatomic results and clinical outcome.

PURPOSEWe describe our therapeutic strategy and correlate the anatomic results and clinical outcomes in patients who received immediate fibrinolytic therapy for thromboembolic complications occurring during endovascular treatment of an intracerebral aneurysm.METHODSThe medical records and angiographic examinations of 19 patients were reviewed. All endovascular procedures were performed with the patients under general anesthesia and fully heparinized. Thirteen patients received an intravenous bolus injection of aspirin. Thromboemboli occurred during catheterization or insertion of embolic material (Guglielmi detachable coils or mechanical detachable spirals) or in the first hours after the intervention. Clot distribution was within the MCA territory in 14 patients, the ACA in three patients, and the basilar trunk in two patients. A continuous intraarterial injection of urokinase was administered immediately, either superselectively distal to the thrombus or selectively within or closely proximal to the thrombus. In nine cases, chemical lysis was combined with mechanical clot fragmentation. Initial anatomic recanalization as well as clinical outcome at 3 months were evaluated.RESULTSTen patients showed complete recanalization and nine patients showed partial recanalization. Fourteen patients had a good clinical recovery. One patient was moderately disabled and two were severely disabled according to their scores on the Glasgow outcome scale. Two patients died, one as a consequence of the preexisting subarachnoid hemorrhage and the other because of a large intracerebral hematoma that developed after fibrinolysis. Of the 14 patients with a good clinical outcome, nine exhibited complete recanalization and five partial recanalization.CONCLUSIONPharmacological thrombolysis seems to be a safe and efficient therapy that facilitates the natural fibrinolytic process, increasing the rate of recanalization in thromboembolic events. Clot fragmentation and superselective drug infusion appear to improve the rate of recanalization. Complete recanalization increases the chance of a better clinical outcome; however, clinical outcome does not always correspond to recanalization and vice versa.     

Daily catheter-directed single dosing of t-PA in treatment of acute deep venous thrombosis of the lower extremity

The strong fibrin affinity of recombinant tissue plasminogen activator (rt-PA) theoretically obviates continuous infusion or replacement of t-PA after direct intrathrombic injection. This hypothesis led the authors to evaluate single daily catheter-directed injection of rt-PA as a thrombolytic treatment for acute deep vein thrombosis of the lower extremity. Once-daily injection of rt-PA was performed in large thrombosed veins (popliteal or larger) with use of pulse-spray catheters and in small thrombosed veins in patients' calves with use of 3-4-F coaxial catheters. Patients received only full systemic anticoagulation on his/her patient care unit. This dosing regimen has been tested in 10 patients (12 legs) with a maximum dose of 50 mg per leg per day. Extensive thrombolysis was achieved in nine patients and partial thrombolysis was achieved in one patient, at an average total dose of 106 mg of rt-PA per leg. Minor bleeding was seen in three patients and no transfusions were needed. Our technique and the rationale for this pilot study is the focus of this article.     

Endovascular Venous Thrombolysis in Children Younger than 24 Months

PurposeTo evaluate the technical feasibility and safety of percutaneous endovascular thrombolysis for extremity deep venous thrombosis (DVT) in children < 24 months old.Materials and MethodsA retrospective chart review of a clinical and imaging database was performed for pediatric patients who underwent endovascular therapy for DVT between January 2010 and July 2013. Indications, techniques, technical and clinical success, and complications were reviewed. Techniques for thrombolysis included catheter-directed therapy (CDT) using alteplase infusion via a multi–side hole catheter, mechanical thrombectomy, and angioplasty. Short-term outcomes were assessed using surgical and imaging follow-up examinations for patency of the targeted vessel. Patients included 11 children (mean age, 9 mo; range, 3 wk–23 mo) who consecutively underwent endovascular thrombolysis for upper extremity (n = 6) or lower extremity (n = 5) DVT. The most common indication was preservation of venous access for future cardiac surgery or medical therapy.ResultsThe most common risk factor was the presence of a central venous catheter (10 of 11 patients). All patients with upper extremity DVT had congenital heart disease. CDT and angioplasty were performed in all patients. Venous patency was established in all patients. A grade III (95%–100%) thrombolysis response was achieved in seven patients, and a grade II (50%–95%) thrombolysis response was achieved in four patients. A major complication of pulmonary embolism occurred in one patient with upper extremity thrombolysis and was managed by intravenous systemic alteplase and heparin. No recurrence of thrombosis was found on average follow-up of 11.8 months (range, 1–41 mo).ConclusionsPercutaneous endovascular thrombolysis for extremity DVT is safe and technically feasible in children < 24 months old.     

Local thrombolysis for patients of severe cerebral venous sinus thrombosis during puerperium

Objective

To explore and evaluate the efficacy of intrasinus thrombolysis (IST) in patients with cerebral venous sinus thrombosis (CVST) during postpartum period.

Methods

11 patients during postpartum period with CVST who received IST during July 2007–November 2011 were included. Urokinase was infused into the sinuses via a microcatheter. Magnetic resonance venography (MRV) was performed to assess the recanalization of venous sinuses.

Results

Before discharge, the intracranial pressure in 11 patients was under 200 mmH₂O. MRV confirmed that venous sinus of 9 patients were smooth. The cortex venous and deep venous recovered to normal. Venous sinus of 2 patients recanalized partly, and cortex venous and deep venous had compensation. 9 patients had good outcome and 2 patients had only mild deficits.

Conclusion

Intrasinus thrombolysis is safe and effective in patients with severe cerebral venous sinus thrombosis during postpartum period.     

Diffusion- and perfusion-weighted MR imaging of dural sinus thrombosis

A patient with dural sinus thrombosis had progressively worsening symptoms and signs that resolved after intradural thrombolysis. Intradural sinus pressures were 54 mm Hg. Echo-planar MR imaging revealed complex abnormalities of diffusion and widespread delay in mean transit time that improved immediately after thrombolysis. This case suggests that diffusion- and perfusion-weighted imaging can provide valuable information noninvasively to help triage patients with dural sinus thrombosis between conservative and aggressive management.     

Alteplase for hemodialysis access graft thrombolysis

PURPOSE: To evaluate the efficacy and safety of alteplase, a recombinant tissue plasminogen activator, in hemodialysis access graft thrombolysis. MATERIALS AND METHODS: From November 1999 to May 2001, 68 episodes of occlusion in 50 grafts (in 49 patients) were included in the study. Occlusion was treated with pulse-spray (n = 41) or lyse-and-wait (n = 27) thrombolysis with use of alteplase. Balloon angioplasty of all identified stenoses was performed. The arterial plug was mobilized with the Fogarty maneuver. RESULTS: Procedural success was achieved in 64 of 68 episodes (94%) with a dose of 2-10 mg (mean = 4.13 mg) of alteplase, allowing successful hemodialysis within 24 hours. Failures (6%) were the result of PTA perforation (one of 68), nonnegotiable outflow occlusion (one of 68), delayed bleeding (one of 68), and balloon bursting and shearing becoming occlusive within the graft (one of 68). Primary and secondary patency rates were 72% and 87% at 30 days, 57% and 80% at 90 days, and 44% and 72% at 180 days, respectively. Arterial emboli (two of 68) were treated by Fogarty balloon retrieval and alteplase infusion locally over the course of 20 minutes. One of two PTA perforations was controlled by balloon tamponade. CONCLUSION: Alteplase can be used successfully for hemodialysis graft thrombolysis.     

Documented development of a dural arteriovenous fistula in an infant subsequent to sinus thrombosis: case report and review of the literature

Controversy exists as to whether sinus thrombosis is the cause or the result of dural arteriovenous fistula (DAVF) and to whether DAVF are congenital or acquired lesions, especially in children. An infant presented with rupture of an anterior communicating artery aneurysm diagnosed with computed tomography angiography and catheter angiography. Pretreatment hospital course was complicated by extensive dural sinus thrombosis. Subsequent arteriography showed a new adult-type dural arteriovenous fistula to the previously thrombosed right sigmoid sinus. This is the first report of definitive angiographic documentation of the development of an adult-type DAVF after recanalization of a thrombosed dural sinus in a child. This case confirms the acquired etiology of at least one type of DAVF in children, even at this young age. We review the previously documented cases of formation of DAVF subsequent to sinus thrombosis with serial angiography in adults.