Risk factors for rectal bleeding after volumetric-modulated arc radiotherapy of prostate cancer.

Background: It is crucially important to understand the risk factors for rectal bleeding after volumetric-modulated arc radiotherapy (VMAT) for prostate cancer to prevent subsequent rectal bleeding. We assayed clinical and dosimetric data to investigate the risk factors for rectal bleeding after VMAT of prostate cancer. Materials and methods: This study included 149 patients with prostate cancer who received VMAT from February, 2012 to June, 2020. Irradiated total doses were 78 Gy/39 fractions in 33 patients (22.1%), 76 Gy/38 fractions in 89 (59.7%), 74 Gy/37 fractions in 4 (2.7%), and 72 Gy/36 fractions in 23 (15.4%). We investigated multiple clinical and dosimetric factors with reference to rectal bleeding. Results: The median observation period was 38 months. Fourteen patients (9.4%) experienced rectal bleeding: five (3.4%) were classified as Grade 2, and nine (6.0%) as Grade 1. There were significant differences between Grade ≥ 1 and Grade 0 patients in the overlap region of the planning target volume (PTV) and the rectum, the rectal V30-75, and the mean rectal dose (p < 0.05). There were significant differences between Grade 2 and Grade 0-1 patients in rectal V30-65 and mean rectal dose (p < 0.05). Conclusions: Rectal bleeding occurred, but its grades and rate of occurrence were permissible. Higher rectal doses were shown to be related to rectal bleeding, and reduction of low/intermediate and mean rectal doses will be important for preventing rectal bleeding.

Direct Carotid Cavernous Fistulas.

A direct carotid cavernous fistula (CCF) is an abnormal shunt between the internal carotid artery (ICA) and the cavernous sinus (CS). Traumatic CCF is the most common type, accounting for up to 75% of all CCFs. For the management of direct CCF, endovascular therapy has become the standard. For successful endovascular therapy, evaluation of the size and location of orifice of the CCF, venous drainage, and tolerance for ICA occlusion on cerebral angiography is necessary. Multi-planner reformatted images of 3D rotation angiography are useful to visualize the fistula and compartments of the CS precisely. Due to the limited commercial availability of detachable balloons, detachable coils have become a widely employed endovascular tool for the treatment of direct CCFs. The advantageous aspects of coil application are their easy retrievability and better control. In the case of large/multiple fistulas, adjunctive techniques, including balloon- and stent-assisted techniques, are often needed to occlude the CCF while preserving the ICA. To avoid cranial nerve palsy related to over-packing of the CS with detachable coils or a detachable balloon, selective embolization of the fistula portion is required. Use of liquid embolic materials and covered stents was recently reported as another adjunctive technique. In cases in which it is impossible to occlude the CCF while preserving the ICA, parent artery occlusion (PAO) is considered. The selection of additional/alternative techniques and devices depends on the anatomy and hemodynamics of each CCF, and the skill and experience of individual operators.

MDCT features of strangulated ileus due to an appendix epiploica of the sigmoid colon: four cases and a review of the literature.

PURPOSE: The aim of this study was to investigate the multidetector computed tomography (MDCT) features of strangulated ileus caused by epiploic appendix of the sigmoid colon. METHODS: We retrospectively evaluated MDCT images of four patients who underwent surgery in our hospital between 2011 and 2014. Patients were aged from 66 to 79 years, and two were female. RESULTS: Closed loop obstruction of the small bowel was confirmed in all patients. A fatty peritoneal band around the orifice of the ileus was detected in two patients, but was equivocal in the other two patients. Traction of the sigmoid colon toward the hilum of the closed loop of the small bowel was obvious in three patients. CONCLUSION: When traction of the sigmoid colon is detected in MDCT in a case of closed loop obstruction of the small bowel, strangulated ileus caused by an epiploic appendix should be considered in the differential diagnosis.

Renal Arteriovenous Shunts: Clinical Features, Imaging Appearance, and Transcatheter Embolization Based on Angioarchitecture.

Renal arteriovenous (AV) shunt, a rare pathologic condition, is divided into two categories, traumatic and nontraumatic, and can cause massive hematuria, retroperitoneal hemorrhage, pain, and high-output heart failure. Although transcatheter embolization is a less-invasive and effective treatment option, it has a potential risk of complications, including renal infarction and pulmonary embolism, and a potential risk of recanalization. The successful embolization of renal AV shunt requires a complete occlusion of the shunted vessel while preventing the migration of embolic materials and preserving normal renal arterial branches, which depends on the selection of adequate techniques and embolic materials for individual cases, based on the etiology and imaging angioarchitecture of the renal AV shunts. A classification of AV malformations in the extremities and body trunk could precisely correspond with the angioarchitecture of the nontraumatic renal AV shunts. The selection of techniques and choice of adequate embolic materials such as coils, vascular plugs, and liquid materials are determined on the basis of cause (eg, traumatic vs nontraumatic), the classification, and some other aspects of the angioarchitecture of renal AV shunts, including the flow and size of the fistulas, multiplicity of the feeders, and endovascular accessibility to the target lesions. Computed tomographic angiography and selective digital subtraction angiography can provide precise information about the angioarchitecture of renal AV shunts before treatment. Color Doppler ultrasonography and time-resolved three-dimensional contrast-enhanced magnetic resonance angiography represent useful tools for screening and follow-up examinations of renal AV shunts after embolization. In this article, the classifications, imaging features, and an endovascular treatment strategy based on the angioarchitecture of renal AV shunts are described.

Anatomical variations in termination of the uncal vein and its clinical implications in cavernous sinus dural arteriovenous fistulas.

INTRODUCTION: The aim of the study was to investigate the variations in the uncal vein (UV) termination and its clinical implication in cavernous sinus dural arteriovenous fistulas (CSDAVFs). METHODS: Biplane cerebral angiography in 80 patients (160 sides) with normal cerebral venous return (normal group) was reviewed with special interest in the termination of the UV. Frequency and types of uncal venous drainage from CSDAVFs in consecutive 26 patients were also analyzed. RESULTS: In the normal group, the UV was identified in 118 sides (74 %). The UV terminated into cavernous sinus (CS) in 41 sides (34 %), the superficial middle cerebral vein (SMCV) in 58 sides (48 %), the laterocavernous sinus (LCS) in 15 sides (13 %), and the paracavernous sinus (PCS) in 4 sides (3 %). Cerebral venous blood via the UV draining into the CS directly (n=41) or through the SMCV and/or the LCS (n=45) was observed in 86 sides (54 %). Uncal venous drainage from CSDAVFs was found in 13 patients (50 %). The CSDAVFs drained directly into the UV in two patients, drained via LCS into the UV in two patients, and drained through the SMCV into the UV in the remaining nine patients. All cases were successfully treated by transvenous embolization with special attention given to uncal venous drainage. CONCLUSION: There are several variations in UV termination according to the embryological development of the primitive tentorial sinus and the deep telencephalic vein. Careful attention should be paid to uncal venous drainage for the treatment of CSDAVFs.

Maxillary artery: functional and imaging anatomy for safe and effective transcatheter treatment.

The maxillary artery is a terminal branch of the external carotid artery. Although the main maxillary artery trunk and most of its branches course within the extracranial space and supply the organs and muscles of the head and neck, other surrounding soft tissues, and the oral and rhinosinusal cavities, other branches supply the dura mater and cranial nerve and can anastomose to the internal carotid artery (ICA). Various pathologic conditions of the intracranial, head, and neck regions can involve the branches of the maxillary artery. Many of these diseases can be treated with endovascular approaches; however, there is a potential risk of complications in the brain parenchyma and cranial nerves related to the meningoneuronal arterial supply and anastomoses to the ICA. Therefore, familiarity with the functional and imaging anatomy of the maxillary artery is essential. In the past, conventional angiography has been the standard imaging technique for depicting the maxillary artery anatomy and related pathologic findings. However, recent advances in computed tomographic, magnetic resonance, and rotational angiography have further elucidated the maxillary artery anatomy by means of three-dimensional representations. Understanding the functional and imaging anatomy of the maxillary artery allows safe and successful transcatheter treatment of pathologic conditions in the maxillary artery territories.

Selective transarterial embolization with n-butyl-2-cyanoacrylate for the treatment of arterial hemorrhage after third molar extraction.

INTRODUCTION: Comprehensive reports concerning selective embolization for arterial bleeding from third molar removal have not been published. We analyzed cases of arterial bleeding from third molar extraction that required transarterial embolization, and we demonstrate representative cases. METHODS: Five consecutive patients (three men and two women, aged 24 to 37 years) who underwent transarterial embolization at our institution were included in this study. Four of them showed postoperative bleeding after lower third molar removal, and one suffered bleeding after upper third molar extraction. The period of time from extraction to embolization varied from 5 h to 5 weeks. RESULTS: Angiography revealed pseudoaneurysms at the inferior alveolar artery in four cases and at the superior alveolar artery in one case. The pseudoaneurysms were selectively embolized using 25-33 % n-butyl-2-cyanoacrylate (NBCA)-lipiodol. All of the cases showed good results angiographically and clinically. Transit hypoesthesia at the region of the mental nerve was observed in one patient. CONCLUSION: Selective transarterial embolization is an effective technique for arterial bleeding from third molar removal when it is difficult to obtain hemostasis by dental procedures. Injection of NBCA can be useful when the alveolar artery is too small to embolize with coils.

Abdominal CT: comparison of low-dose CT with adaptive statistical iterative reconstruction and routine-dose CT with filtered back projection in 53 patients.

OBJECTIVE: The purpose of this article is to retrospectively compare radiation dose, noise, and image quality of abdominal low-dose CT reconstructed with adaptive statistical iterative reconstruction (ASIR) and routine-dose CT reconstructed with filtered back projection (FBP). MATERIALS AND METHODS: Fifty-three patients (37 men and 16 women; mean age, 60.8 years) underwent contrast-enhanced abdominal low-dose CT with 40% ASIR. All 53 patients had previously undergone contrast-enhanced routine-dose CT with FBP. With the scanning techniques masked, two radiologists independently graded images for sharpness, image noise, diagnostic acceptability, and artifacts. Quantitative measures of radiation dose and image noise were also obtained. All results were compared on the basis of body mass index (BMI). RESULTS: The volume CT dose index (CTDI(vol)), dose-length product, and radiation dose for low-dose CT with ASIR were 17 mGy, 860 mGy, and 13 mSv, respectively, compared with 25 mGy, 1,193 mGy, and 18 mSv for routine-dose CT with FBP, representing an approximate overall dose reduction of 33%. Low-dose CT with ASIR had significantly reduced (p < 0.001) quantitative and qualitative assessment of image noise. Image sharpness, however, was significantly reduced for low-dose CT with ASIR (p < 0.001), although diagnostic acceptability and artifact scores were nearly identical to those for routine-dose CT with FBP. The average CTDI(vol) dose reduction was 66% for patients with a BMI of less than 20 and 23% for patients with a BMI of 25 or greater. CONCLUSION: Compared with routine-dose CT with FBP, abdominal low-dose CT with ASIR significantly reduces noise, thereby permitting diagnostic abdominal examinations with lower (by 23-66%) radiation doses. Despite reduced image sharpness in average and small patients, low-dose CT with ASIR had diagnostic acceptability comparable to that of routine-dose CT with FBP.

Endovascular recanalization of acute intracranial vertebrobasilar artery occlusion using local fibrinolysis and additional balloon angioplasty.

INTRODUCTION: Vertebrobasilar artery occlusion (VBO) produces high mortality and morbidity due to low recanalization rate utilization in endovascular therapy. The use of percutaneous transluminal angioplasty (PTA) to improve recanalization rate additional to local intra-arterial fibrinolysis (LIF) was investigated in this study. Results obtained following recanalization therapy in acute intracranial VBO are reported. METHODS: Eighteen consecutive patients with acute VBO underwent LIF with or without PTA, from August 2000 to May 2006. Eight patients were treated using LIF alone, and ten required additional PTA. Rate of recanalization, neurological status before treatment, and clinical outcomes were evaluated. RESULTS: Of 18 patients, 17 achieved recanalization. One procedure-related complication of subarachnoid hemorrhage occurred. Overall survival rate was 94.4% at discharge. Seven patients achieved good outcomes [modified Rankin scale (mRS) 0-2], and the other 11 had poor outcomes (mRS 3-6). Five of six patients who scored 9-14 on the Glasgow Coma Scale (GCS) before treatment displayed good outcomes, whereas ten of 12 patients who scored 3-8 on the GCS showed poor outcomes. GCS prior to treatment showed a statistically significant correlation to outcomes (p < 0.05). Moreover, the National Institutes of Health Stroke Scale (NIHSS) before treatment correlated well with mRS (correlation coefficient 0.487). No statistical difference between the good and poor outcome groups was observed for the duration of symptoms, age, etiology, and occlusion site. CONCLUSIONS: Endovascular recanalization can reduce mortality and morbidity of acute VBO. Good GCS and NIHSS scores prior to treatment can predict the efficacy of endovascular recanalization.

Arterial supply to the pancreas; variations and cross-sectional anatomy.

The pancreas has complex arterial supplies. Therefore, special attention should be paid in pancreatic arterial intervention for patients with acute pancreatitis and pancreatic carcinomas. Knowledge of pancreatic arterial anatomy and arterial territory is important not only to perform pancreatic arterial intervention, but to read the pancreatic angiography and cross-sectional image. We reviewed 226 selective abdominal angiography and CT scans during selective arteriography (CTA) of common hepatic artery, superior mesenteric artery, splenic artery, or peripancreatic arteries including posterior superior pancreaticoduodenal artery, anterior superior pancreaticoduodenal artery, inferior pancreaticoduodenal artery, and dorsal pancreatic artery. CTA images were evaluated to clarify the cross-sectional anatomy of the pancreatic arterial territory. Variations of the peripancreatic arteries were also investigated. In this exhibit, schemes and illustrative cases demonstrate pancreatic arterial territory and variations.

Basal cerebral venous drainage from cavernous sinus dural arteriovenous fistulas.

INTRODUCTION: This study aimed to define the patterns of basal cerebral venous drainage (BCVD) from cavernous sinus dural arteriovenous fistulas (CSDAVFs). MATERIALS AND METHODS: Forty sets of selective angiographic data from 36 patients with spontaneous CSDAVFs (age range, 53-79 years) were retrospectively analyzed for their drainage patterns. Three types of BCVD were observed, i.e., superolateral type, BCVD via the deep middle cerebral vein or uncal vein; posterolateral type, BCVD via the superior petrosal sinus and petrosal vein; and posteromedial type, BCVD via the bridging vein and the anterior pontomesencephalic vein. MR images and/or 3D-DSA images were also reviewed when available. RESULTS: BCVD from CSDAVF was found in 12 patients (30%), and the other drainage routes included the superior ophthalmic vein in 25 (63%), the inferior petrosal sinus in 17 (43%), the superficial middle cerebral vein in 17 (43%), intercavernous sinus in 15 (38%), the superior petrosal sinus in seven (18%), and pterygoid plexus in two (5%), respectively. In 12 patients with BCVD, superolateral type was found in four (33%), posterolateral type in five (42%), and posteromedial type in seven (58%). Four cases of posteromedial type were associated with other types of BCVD. CONCLUSION: CSDAVFs are often associated with BCVD via three different pathways. The posteromedial type via the bridging vein is the most frequent type of BCVD.

The anterior medullary-anterior pontomesencephalic venous system and its bridging veins communicating to the dural sinuses: normal anatomy and drainage routes from dural arteriovenous fistulas.

INTRODUCTION: We evaluated the normal venous anatomy of the anterior medullary/anterior pontomesencephalic venous (AMV/APMV) system and bridging veins connected to the dural sinuses using magnetic resonance (MR) imaging and demonstrated cases of dural arteriovenous fistulas (DAVFs) with bridging venous drainage. MATERIALS AND METHODS: MR images obtained using a 3D gradient echo sequence in 70 patients without lesions affecting the deep or posterior venous channels were reviewed to evaluate the normal anatomy of the AMV/APMV system and bridging veins. MR images and digital subtraction angiography in 80 cases with intracranial or craniocervical junction DAVFs were reviewed to evaluate the bridging venous drainage from DAVFs. RESULTS: MR images clearly revealed AMV/APMV in 35 cases. Fifteen cases showed a direct connection between AMV and APMV, while 15 cases showed an indirect communication via the transverse pontine vein or the bridging vein. In the five remaining cases, the AMV and APMV end separately to the bridging vein or the transverse pontine vein. Bridging veins were identified in 34 cases, connecting to the cavernous sinus in 33, to the suboccipital cavernous sinus in 11, and the inferior petrosal sinus in five cases. In 80 DAVF cases, seven of 40 cavernous sinus DAVFs, two craniocervical junction DAVFs, and one inferior petrosal sinus DAVF drained via bridging veins to the brain stem. CONCLUSION: The AMV/APMV and bridging veins showed various anatomies and frequently showed a connection to the cavernous sinus. Knowledge of the venous anatomy is helpful for the diagnosis and intravascular treatment of DAVFs.

Hypothermia protects cultured human retinal pigment epithelial cells against indocyanine green toxicity.

PURPOSE: The aim of this study was to determine whether indocyanine green (ICG) is toxic to cultured human retinal pigment epithelial (ARPE-19) cells, and whether hypothermia can protect the ARPE-19 cells against the ICG toxicity. METHODS: Cultured ARPE-19 cells were exposed to 0.25, 0.5, 1, 2.5, and 5 mg/mL of ICG dye at 37 and 4 degrees C for 30 min. The percentage of ARPE-19 cells that survived was determined by resazurin 1 day after the exposure. RESULTS: Exposure of the RPE cells to a hypotonic saline solution with an osmolarity equal to 5 mg/mL of ICG did not induce a statistically significant decrease in the percentage of RPE cells that survived. Exposure of the ARPE-19 cells to ICG induced a significant decrease in the percentage of cell survival at all concentrations of ICG (P<0.05), except in 0.25 mg/mL at 37 degrees C. At 4 degrees C, on the other hand, ICG induced a statistically significant decrease in the percentage of RPE cell survival only at 5 mg/mL of ICG (P<0.05). CONCLUSIONS: These results indicate that ICG is toxic to human RPE cells in culture, and that cell death cannot be attributed to the low osmolarity. Hypothermia of 4 degrees C has a protective effect against ICG toxicity.

Visual function with acupuncture tested by visual evoked potential.

Visual evoked potential (VEP) testing is used frequently and is an important ophthalmologic physiological test to examine visual functions objectively. The VEP is a complicated waveform consisting of negative waveform named N75 and N135, and positive waveform named P100. Delayed P100 latency and greatly attenuated amplitude on VEP are known characteristics for diagnosing optic nerve disease. Acupuncture has been used to treat wide clinical symptoms with minimal side effects. The confirmation of the efficacy of acupuncture generally relies on subjective symptoms. There is not much scientific evidence supporting the acupuncture treatments for eye diseases up to today. However, the VEP test can evaluate objectively and numerically the efficacy of the treatment by the acupuncture. We analyzed 19 healthy subjects (38 eyes). The P100 latencies in the group of less than 101.7 msec (total average) before acupuncture stimulations were not different than those after treatment (98.2 +/- 3.0 msec, 98.2 +/- 4.0 msec, respectively, p = 0.88, n = 17), but the latencies in those subjects with longer or equal to 101.7 msec were statistically different after acupuncture (104.6 +/- 2.8 msec, 101.9 +/- 3.7 msec, respectively, p = 0.006, n = 21). These results show that the acupuncture stimulation contributes to the P100 latencies of pattern reversal (PR)-VEP to some subjects who have delayed latencies, and this electrophysiological method is a valuable technique in monitoring the effectiveness of acupuncture therapy in the improvements of visual functions. The purpose of this study is to evaluate the physiological effects by acupuncture stimulations using PR-VEP in normal subjects.

Hypothermia of 8 degrees C protects cultured retinal pigment epithelial cells and retinal ganglion cells against trypan blue toxicity.

PURPOSE: To determine whether hypothermia of 8 degrees C can protect cultured human retinal pigment epithelial (ARPE-19) cells and rat retinal ganglion cells (RGC-5) against trypan blue (TB) toxicity. DESIGN: Laboratory investigation. METHODS: ARPE-19 cells and RGC-5 were exposed to balanced salt solution as controls, and 0.05% and 0.5% TB at 37 degrees C, and at 8 degrees C for one minute. The percentage of surviving cells was determined by the resazurin test. RESULTS: TB induced a statistically significant decrease in the percentage of ARPE-19 cells surviving at 0.5% TB at 37 degrees C (P < .01). Conversely, TB induced a statistically significant decrease in the percentage of RGC-5 surviving at all conditions except for 0.05% TB at 8 degrees C (0.05% 37 degrees C; P < .05, 0.5% 37 degrees C and 8 degrees C; P < .01). CONCLUSIONS: These results indicate that reducing the temperature to 8 degrees C has a protective effect against the TB toxicity for ARPE-19 cells and RGC-5 in culture.

Hypothermia protects cultured human retinal pigment epithelial cells against trypan blue toxicity.

PURPOSE: To determine whether trypan blue (TB) is toxic to cultured human retinal pigment epithelial (ARPE-19) cells, and whether hypothermia can protect ARPE-19 cells against TB toxicity. METHODS: ARPE-19 cells were cultured and exposed to balanced salt solution as a control, while other cells were exposed to 0.05, 0.2, and 0.5% TB dye at 37 and 4 degrees C for 5 and 30 min. The percentage of ARPE-19 cells that survived was determined by resazurin 1 day after the exposure. RESULTS: A statistically significant decrease in the percentage of ARPE-19 cells surviving was found after exposure to 0.2 and 0.5% TB at any temperature or for any exposure duration (p < 0.01). The percentage of RPE cells surviving at 0.05% was not significantly different from that of controls except for a 30-min exposure at 37 degrees C. The percentage of cells surviving at 4 degrees C for a 5-min exposure to 0.5% TB and a 30-min exposure to 0.2 and 0.5% was significantly higher than that at 37 degrees C under each condition (p < 0.01 for all). CONCLUSIONS: These results indicate that TB is toxic to human RPE cells, and the toxicity is dose- and exposure duration-dependent. Exposing the cells at 4 degrees C had a protective effect against higher concentrations or longer exposure durations of TB compared to exposure at 37 degrees C.

Recombinant AAV-transduced iris pigment epithelial cell transplantation may transfer vector to native RPE but suppress systemic dissemination.

PURPOSE: To determine whether adenoassociated virus (AAV) vectors transduced into iris pigment epithelial (IPE) cells and transplanted into the subretinal space of rats will transfer the AAV genome to the host cells and whether the vectors are disseminated systemically. METHODS: Recombinant (r)AAV was transduced into rat IPE cells and transplanted into the subretinal space of rats. For the control, rAAVs alone were injected subretinally. The transplanted IPE cells were detected by LacZ staining. Immunohistochemistry, electron microscopy, electroretinography, and fluorescein-dextran angiography were performed. DNA was extracted from various organs and blood and examined for the AAV genome by polymerase chain reaction. RESULTS: No toxicity from rAAV transduction was observed in vitro. LacZ was expressed in the transplanted cells 1 and 2 weeks after transplantation. At 4 and 12 weeks, fewer transplanted cells were detected than at 1 week, and LacZ expression was occasionally detected at the level of host retinal pigment epithelial (RPE) cells. Expression was also detected in ciliary body epithelial cells. The electroretinograms and fluorescein-dextran angiography were only mildly altered. Significantly lower levels of AAV genome were detected in the organs and blood of rats receiving rAAV-IPE cell transplants than with direct intravenous injection of AAV vectors. CONCLUSIONS: AAV-mediated LacZ was expressed in the transplanted cells after subretinal transplantation, and the transplanted IPE cells may transfer the rAAV to host tissues, such as RPE cells, long after the transplantation. This method of gene delivery did not lead to systemic dissemination of the vectors.

Limitations of three-dimensional reconstructed computerized tomography angiography after clip placement for intracranial aneurysms.

OBJECT: The authors compared the usefulness of three-dimensional (3D) reconstructed computerized tomography (CT) angiography with 3D digital subtraction (DS) angiography in assessing intracranial aneurysms after clip placement. A retrospective review of clinical cases was performed. METHODS: Between May 2001 and May 2003, 17 patients with a total of 20 intracranial aneurysms underwent 3D CT and 3D DS angiography following clip placement. The authors assessed the presence or absence of residual aneurysm necks and stenoocclusive changes in the parent artery and the neighboring artery. The efficacy of CT angiographic visualization was also evaluated. In 12 of the 20 aneurysms, both 3D modalities similarly demonstrated the residual aneurysm neck and stenoocclusive changes in the parent artery and neighboring artery. Three-dimensional CT angiography failed to demonstrate three of the aneurysms, and the studies were not considered suitable for evaluation because of the presence of metallic artifacts. In the remaining five studies, the 3D CT angiograms did not effectively demonstrate the neighboring and parent arteries. The detectability of residual aneurysm necks was correlated with the clip material and with the number of clips applied. CONCLUSIONS: Three-dimensional DS angiography is still necessary in cases involving multiple clips or with cobalt alloy clips because the clips appear as metal artifacts on 3D CT angiography.