Three-dimensional Computed Tomography Angiography Research Articles

Detection and Evaluation of Intracranial Aneurysms with 3D-CT Angiography and Compatibility of Simulation View with Surgical Observation.

The aim of this study was to report our experience with a 64-channel computerized tomography (CT) scanner as the primary choice on the detection of intracranial aneurysms. Comparison of intracranial aneurysms with the simulated images obtained via three-dimensional computed tomography angiography (3D-CTA) in pterional approach was also aimed. Among 288 consecutive patients who had intracranial aneurysms detected on 64-slice CTA, a total of 337 aneurysms were detected. CTA simulation images and intraoperative images were compared with regards to size, shape, and orientation. In one of the 22 CTA-negative cases, one aneurysm was detected in DSA and an additional aneurysm was detected in a patient operated with CTA. Aneurysm size, shape and direction were error free except a few cases. However, CTA was found to be insufficient to show particularly perforating arteries that were smaller than 2 mm in size. As a fast and noninvasive technique, CTA can be used as an initial examination in subarachnoid hemorrhage. Keeping the fact that there can be insufficiency in showing particularly small aneurysms in mind, DSA should be performed on CTA-negative cases and required cases.

Doppler sonography and 3D CT Angiography of Acquired Uterine Arteriovenous Malformations: Report of Two Cases

Uterine Arteriovenous Malformations (AVMs) are rare but life threatening causes of abnormal vaginal bleeding. Accurate clinical and radiological diagnosis is essential because uterine instrumentation that is often used for management of other sources of abnormal bleeding, can lead to massive hemorrhage. Timely diagnosis and early proper treatment can markedly reduce the associated disease mortality. Ultrasound with colour and spectral doppler is the initial imaging modality of choice. Three-dimensional computed tomography (CT) angiography can determine the actual extent of the vascular malformation and helps in pre-interventional planning noninvasively. Uterine AVM can be either congenital or acquired in nature with latter being more common. We hereby report two cases of acquired AVMs diagnosed by color doppler sonography and confirmed by three-dimensional CT angiography. Both the cases reported here had previous history of dilation and curettage for abortion. Clinically one patient presented with profuse uterine bleeding and another with meno-metrorrhagia and both cases underwent surgical removal of uterus.

Anterior communicating artery aneurysms and an unusual variations of anterior comminicating artery detected by 3-D CT angiography

Aneurysmal subarachnoid haemorrhage which has a serious mortality and morbitity ratio, occurs approximately 10/100.000 population per year and it is usally caused by rupture of a cerebral artery aneurysm. Aneurysms are classified saccular, fusiform or dissecan by morphological description. Vascular congenital anomalies of the cerebral vessels contribute to saccular aneurysm formation by increasing hemodynamic stress on the vessel wall. Although anterior communicating artery (ACoA) is the most seen site of vascular anomalies associated with aneurysmal formation, the agenesis of the anterior commmunicating artery is very rare. Here, we present unusual anatomical variations of ACoA detected by three-dimensional CT angiography after subarachnoid hemorrhage.

Three Dimensional Microanatomy of the Ophthalmic Artery: Spontaneous Intracranial-Extracranial Anastomosis Site within the Orbital Cavity.

The aim was to evaluate three-dimensional structure of the ophthalmic artery (OphA). The raw data of the Three-dimensional Computerized Tomography Angiography (3D-CTA) were transferred to computer and recorded in a software program. The study group consisted of 45 (24 female and 21 male) patients. The mean age of the patients was 56 ± 9.5 years. It was found that the entry point of the OphA to the orbital cavity was inferior to the optic foramen in 29 (64.44%) of the cases. The length of the postcanalicular-prelacrimal was 0.54 ± 0.13 centimeters at the right side and 0.51 ± 0.13 centimeters at the left side. The distance of the postlacrimal-presupraorbital segment was 0.43 ± 0.11 centimeters at the right and left sides. The location of the anastomosing site was 0.97 ± 0.42 centimeters from the supraorbital notch. The results of this study showed us that this technique could be used in the evaluation of the three-dimensional microsurgical anatomy of the OphA and its critical extracranial-intracranial anastomosing site.

Three-Dimensional Microsurgical Anatomy of the Choroid Plexus Using the Volume Rendering Technique.

The choroid plexus (CP) is a specific anatomical structure producing cerebrospinal fluid into the ventricular space. The three-dimensional anatomical structure of the choroid plexus located within the lateral ventricle may be evaluated by using the three dimensional volume rendering technique (3D-VRT) from acquired two-dimensional contrast enhanced computerized tomographic images. The raw data of Three-dimensional Computerized Tomography Angiography (3D-CTA) were transferred into the computer and recorded in a software program. These images were evaluated in terms of anatomical shape, borders, extensions length and dimensions. The patient group consisted of 57 (27 female and 30 male) patients. The mean age of the patients was 55±9 years. In male individuals, the distance of the superior tip from Frazier's point was 7.96±0.71 centimeters at the right side. In males, the distance of the inferior tip of the CP was estimated as 1.93±0.26 centimeters posterior-lateral from the anterior clinoid process, 1.64±0.23 centimeters posterior-lateral from the bifurcation of internal carotid artery, and 2.86±0.23 centimeters posterior-medial from the bifurcation of middle cerebral artery on the right side. The results of this study showed us that this technique could be used in the three-dimensional evaluation of some anatomical structures such as the choroid plexus.

Fusiform Enlargement of the Superficial Temporal Artery in the Cases with Intracranial Aneurysm.

The superficial temporal artery is one of the main terminal branches of the external carotid artery. This artery ascends through the lateralposterior margin of the zygomatic arch to reach the temporal region of the scalp. The superficial temporal artery divides its frontal and parietal branches around the zygomatic arch. The raw data of the Three-dimensional Computerized Tomography Angiography (3D-CTA) were transferred to computer and recorded in a software program. This software program created the three-dimensional images of the superficial temporal artery using these transferred raw data with volume rendering technique. Fifteen cases (5 female and 10 male, mean age 54.26 ± 12.35 years) with intracranial aneurysm were evaluated in terms of the type, location and dimensions of the fusiform enlargements. Fusiform enlargement was bilateral in eleven of the cases. Remaining four cases have unilateral fusiform enlargement of the superficial temporal artery. Fusiform enlargement of the superficial temporal artery may be seen in the cases with intracranial aneurysms. 3D-CTA should be carefully evaluated in the demonstration of extracranial-intracranial vascular pathologies.

The preparation of anastomosis site at the insular segment of middle cerebral artery.

Background:An anastomosis at the insular segment of the middle cerebral artery (M2) is often required in cerebral reconstruction with high- or low-flow bypass. It is necessary to create a shallow, wide, fixed, and bloodless anastomosis field to achieve a safe and quick anastomosis for low surgical morbidity. We describe a method to perform a safe and quick anastomosis.Methods:From 2009 to 2013, the technique was used in 20 procedures to create an extracranial M2 high-flow bypass. The Sylvian fissure was dissected wide open to expose the M2. A silicon sheet was laid under M2 and the absorbable gelatin-compressed sponges were inserted between M2 and the insula cortex to lift up the M2 and fix it. The rolling surgical sheets were placed at each edge of the dissected Sylvian fissure, instead of brain spatulas. Finally, a small suction tube was placed at the Sylvian fissure and cerebrospinal fluid was continuously sucked. The postoperative patency of the bypass was evaluated by three-dimensional computed tomographic angiography (3D-CTA) in the acute and chronic stages.Results:In all cases, the operation field acquired for the anastomosis was adequate. The average time required for the procedure was 19 min 27 s. Good patency of all high-flow grafts was confirmed by postoperative three-dimensional computed tomography angiography (3D-CTA).Conclusion:In our series, there were no technical complications related to the anastomosis at M2 performed according to our method.

Is three-dimensional CT angiography safer than conventional cerebral angiography in detecting aneurysms in acute subarachnoid hemorrhage ?

Is three-dimensional CT angiography safer than conventional cerebral angiography in detecting aneurysms in acute subarachnoid hemorrhage ?

Preliminary study of whole-brain CT perfusion imaging in patients with intracranial tumours adjacent to large blood vessels

To explore the value of whole-brain computed tomography perfusion (WBCTP) imaging in patients with intracranial tumours adjacent to large blood vessels. WBCTP with 320-row CT was performed in 35 patients with clinically and pathologically diagnosed intracranial tumours adjacent to large blood vessels. Three-dimensional CT perfusion (3D-CTP) parameter maps of cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and dynamic CT angiography (4D-CTA) images were obtained simultaneously. Three-dimensional CT angiography (3D-CTA) images, including volume rendering (VR), minimum intensity projection (MIP), and fusion images of the tumour with CTA, were reconstructed using post-processing techniques. The image quality, CTP and CTA characteristics were analysed. All WBCTP images could be evaluated without artefacts. Abnormal perfusion areas were identified on 3D-CTP maps. Significant differences in CBF and CBV were detected between meningioma (n = 18) and glioma (n = 16; p < 0.05). The blood supplying and draining veins of the tumour could be observed on CTA in 30 cases. The surrounding large arteries were compressed and dislocated by tumours in 18 cases and were wrapped up in six cases. Compression and mild deformation of the venous sinuses were visualized in 10 cases, and in four cases, the superior sagittal sinus was invaded and the vessel lumen was partially blocked. Comprehensive evaluation of intracranial tumours adjacent to large blood vessels could be achieved with the WBCTP technique. This technique has great value for the diagnosis of intracranial tumours and for evaluation of the relationship of intracranial tumours to surrounding large blood vessels.

Evaluation of the relationship between extremity soft tissue sarcomas and adjacent major vessels using contrast-enhanced multidetector CT and three-dimensional volume-rendered CT angiography: a preliminary study

Accurate description of the relationship between extremity soft tissue sarcoma and the adjacent major vessels is crucial for successful surgery. In addition to magnetic resonance imaging (MRI) or in patients who cannot undergo MRI, two-dimensional (2D) postcontrast computed tomography (CT) images and three-dimensional (3D) volume-rendered CT angiography may be valuable alternative imaging techniques for preoperative evaluation of extremity sarcomas. To preoperatively assess extremity sarcomas using multidetector CT (MDCT), with emphasis on postcontrast MDCT images and 3D volume-rendered MDCT angiography in evaluating the relationship between tumors and adjacent major vessels. MDCT examinations were performed on 13 patients with non-metastatic extremity sarcomas. Conventional CT images and 3D volume-rendered CT angiography were evaluated, with focus on the relationship between tumors and adjacent major vessels. Kappa consistency statistics were performed with surgery serving as the reference standard. The relationship between sarcomas and adjacent vessels was described as one of three patterns: proximity, adhesion, and encasement. Proximity was seen in five cases on postcontrast CT images or in eight cases on volume-rendered images. Adhesion was seen in three cases on both postcontrast CT images and volume-rendered images. Encasement was seen in five cases on postcontrast CT images or in two cases on volume-rendered images. Compared to surgical results, postcontrast CT images had 100% sensitivity, 83.3% specificity, 87.5% positive predictive value, 100% negative predictive value, and 92.3% accuracy in the detection of vascular invasion (κ = 0.843, P = 0.002). 3D volume-rendered CT angiography had 71.4% sensitivity, 100% specificity, 100% positive predictive value, 75% negative predictive value, and 84.6% accuracy in the detection of vascular invasion (κ = 0.698, P = 0.008). On volume-rendered images, all cases with adhesion or encasement had arterial stenosis and all tumors' feeding arteries were clearly depicted. 2D postcontrast CT images are superior to 3D volume-rendered CT angiography in evaluating the relationship between extremity sarcomas and adjacent major vessels. 3D volume-rendered CT angiography is good at assessing the tumor's blood supply, the longitudinal extent of vascular involvement, and the vascular narrowing due to the tumor.

Three-dimensional Ultrasound Improves the Accuracy of Diameter Measurement of the Residual Sac in EVAR Patients

Discrepancy between maximum diameters obtained with two-dimensional ultrasound and computed tomography (CT) after endovascular aneurysm repair (EVAR) is well known. The maximal diameter is ideally measured perpendicular to the centerline, a methodology so far only feasible with three-dimensional (3D) CT and magnetic resonance angiography (MRA). We aimed to investigate the agreement between 3D ultrasound and 3D CT and to determine reproducibility measures. Prospective study comparing 3D ultrasound with 3D CT in 124 consecutive patients seen 3 or 12 month after EVAR. Replacing 2D with 3D ultrasound, the mean difference was improved from 6.0 mm to -1.3 mm (p < .001), and the range of variability was reduced from 9.4 mm to 6.6 mm (p = .009) using 3D CT as the gold standard. The mean difference between 3D ultrasound and 3D CT maximum diameter of the residual sac was -1.3 mm with upper and lower limits of agreement of 5.2 mm and -7.9 mm, respectively. Reproducibility measures of 3D ultrasound were ± 4 mm. 3D ultrasound correlate significantly better to 3D CT than the currently used 2D ultrasound method when assessing maximum diameter of the residual sac after EVAR, and reproducibility measures were within clinical acceptable values.

A TREX1 mutation causing cerebral vasculopathy in a patient with familial chilblain lupus

The patient regularly developed chilblains on her fingers and toes, particularly prominent during the winter beginning at 1 year of age (Fig. 1a). At 18, 19 and 21 years of age, she suffered from cerebral infarctions. At 21 years of age, the patient presented with digital gangrene that subsequently led to finger amputation. A skin biopsy suggested small vessel angitis. Steroid therapy was administered and the chilblain improved. The dose of prednisolone was gradually decreased from 30 mg/day. At 28 years of age, the patient presented with left hemiparesis while being treated with 7.5 mg/day of prednisolone. The patient was alert and at presentation there was no finding suggestive of encephalopathy. Brain magnetic resonance imaging (MRI) disclosed an infarction in the internal capsule. Three-dimensional computed tomography angiography (3D-CTA) demonstrated multiple cerebral aneurysms (Fig. 1b). She had no history of either cocaine use or other stimulant drug abuse. Ophthalmic examinations showed no finding of retinal vasculopathy. Laboratory investigations were unremarkable, except for the presence of antinuclear antibodies, with a titer of 1:20 and a speckled pattern. A hypercoagulable panel (lupus anticoagulant and anticardiolipin antibody titers, the protein C and S levels and the antithrombin III level) and tests for cryoglobulinemia were negative. A cerebrospinal fluid (CSF) examination revealed an increased interleukin-6 (IL6) level of 37.9 pg/ml (normal range B4.3 pg/ml). The dose of prednisolone was increased to 60 mg/day. After 2 months, 3D-CTA showed reduced cerebral aneurysms (Fig. 1c). At 29 years of age, the patient presented with dysarthria after the dose of prednisolone was reduced to 5 mg/day. Brain MRI revealed a thalamic infarction (Fig. 1d). Old small infarctions were observed on T2-weighted images (Fig. 1e–g). 3D-CTA demonstrated no obvious cerebral aneurysms. However, a detailed evaluation of cerebral angiography demonstrated multiple small aneurysms (Fig. 1h). The dose of prednisolone was increased to 15 mg/day. After 1 month, a CSF examination showed a decreased IL-6 level of 7.6 pg/ml. The patient’s mother, grandmother, brother and sister also had chilblains starting in early childhood (Fig. 1i). However, none of them had any history of stroke except for the grandmother, who had died from a subarachnoid hemorrhage at 45 years of age. Blood samples for a genetic analysis were collected from the patient and other family members with a history of chilblains. We performed direct sequencing of all coding exons of TREX1. A heterozygous TREX1 p.Asp18Asn mutation was identified in the present family (Fig. 1j). Chilblain lupus erythematosus is a rare chronic form of cutaneous lupus erythematosus characterized by coldinduced skin lesions in acral locations that usually affect middle-aged females [1]. A familial form of chilblain lupus manifesting in early childhood was first described by LeeKirsh et al. in 2006 [2]. To date, heterozygous mutations in TREX1 [3–7] and SAMHD1 [8] have been reported in patients with familial chilblain lupus (FCL). TREX1 is the major 30 ? 50 exonuclease in mammalian cells. Mutation of TREX1 results in accumulation of altered DNA, which triggers an abnormal innate immune response [3, 4]. Mutations in TREX1 are also responsible for autoimmune diseases including systemic lupus erythematosus, K. Yamashiro (&) R. Tanaka Y. Li M. Mikasa N. Hattori Department of Neurology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan e-mail: kazuo-y@juntendo.ac.jp

Intracranial extravasation of contrast medium during diagnostic CT angiography in the initial evaluation of subarachnoid hemorrhage: report of 16 cases and review of the literature

IntroductionThree-dimensional CT angiography (3D-CTA) is increasingly used in the initial evaluation of subarachnoid hemorrhage (SAH). However, there is a risk of aneurysm re-rupture in the hyperacute phase. We sought to clarify the incidence of re-rupture and characterize the subgroup in which extravasation of contrast media was seen on 3D-CTA.MethodsWe examined the records of 356 consecutive patients presenting to our institution with non-traumatic SAH between October 2003 and December 2011. After resuscitation, patients with poor grade SAH underwent CT then 3D-CTA while sedated, mechanically ventilated and with a target systolic blood pressure of 120 mmHg.Results336 patients underwent 3D-CTA; 20 died without return of spontaneous circulation. Extravasated contrast medium was seen in 16 (4.8%), 15 (4.5%) at the initial evaluation. Their World Federation of Neurosurgical Societies Grade was V; one patient was resuscitated from cardiac arrest. The mean times from onset to arrival and to CTA were 43.7 minutes and 71.8 minutes, respectively. Ten patients (62.5%) had episodes suggestive of aneurysm re-rupture before 3D-CTA. Surgical clipping, evacuation of hematoma and wide decompressive craniectomy was completed in six patients and one underwent coil embolization. Two of 16 patients survived: one with moderate disability and one made a good recovery.ConclusionsContrast extravasation was detected by 3D-CTA in 4.5% of cases despite intensive resuscitation, suggesting that continuous or intermittent rebleeding may occur frequently in the hyperacute phase. The consequences of rebleeding are devastating; however, favorable results can be obtained with immediate aneurysm repair with decompression and intensive neurocritical care.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-413) contains supplementary material, which is available to authorized users.

Three-dimensional renal CT angiography for guiding segmental renal artery clamping during laparoscopic partial nephrectomy

To evaluate the effectiveness of three-dimensional (3D) renal computed tomography angiography (CTA) in guiding segmental renal artery clamping during laparoscopic partial nephrectomy (LPN). Forty-three patients with renal tumours undergoing renal CTA before LPN were retrospectively enrolled in this study. 3D arteriogram reconstructed images were created to identify the renal tumour-supplying arteries. The number and location of these targeted vessels were annotated on 3D images preoperatively and compared with the clamped vessels during LPN. The consistency between target vessels annotated at CTA and clamped arteries at LPN was compared both using a patient-based analysis and vessel-based analysis. The χ(2) test was applied to analyse the influence of tumour size, location, and growth pattern on the number of clamped segmental renal branches. On patient-based analysis, the number of targeted vessels was consistent with the clamped vessels during LPN in 33 of 43 patients. On vessel-based analysis, 56 of 65 target vessels annotated at CTA were clamped during LPN. More segmental renal branches (p=0.04) were clamped in patients with tumours of larger size. Tumour location and growth pattern had no association with the number of clamped segmental branches during LPN. High-quality CTA images and 3D reconstruction images can detect detailed information of tumour-supplying arteries to renal tumours. 3D renal CTA is an effective way to guide segmental renal artery clamping during LPN.

Planning of segmentectomy using three-dimensional computed tomography angiography with a virtual safety margin: Technique and initial experience

ObjectivesIn preoperative segmentectomy simulation for primary lung cancer, it is important to identify the intersegmental pulmonary veins and the relationship between them and the surgical safety margin. We have adopted a method that incorporates a virtual safety margin into three-dimensional computed tomography angiography images in order to plan adequate segmentectomy for lung cancer patients. In this study, we describe the new preoperative planning technique and review cases in which we performed segmentectomy based on its results. MethodsWe reviewed clinical, radiological, and pathological records and selected patients who underwent segmentectomy for a primary lung cancer lesion with a diameter of 2cm or less. These segmentectomies were planned using preoperative three-dimensional computed tomography angiography with a virtual safety margin. ResultsA total of 17 primary lung cancers in 16 patients (11 male and 5 female, aged 52–82 years) were removed by segmentectomy, planned using the new technique. In 6 of 17 tumors (35%) were non-solid type adenocarcinomas, 3 tumors (18%) were partly solid type adenocarcinomas, 6 tumors (35%) were solid type adenocarcinomas and 2 tumors (12%) were squamous cell carcinomas. Pathological examination revealed no positive surgical margins and no lymph node metastases in any patients. ConclusionsThree-dimensional computed tomography angiography with a virtual safety margin was able to non-invasively visualize the three-dimensional distances and the relationships between the primary tumor and intersegmental pulmonary veins. It was able to aid in the preoperative planning of a suitable segmentectomy procedure for patients with a primary lung cancer lesion of 2cm or less in diameter.

Extralobar Pulmonary Sequestration in a 55-Year-Old Man

Pulmonary sequestration is a rare congenital lung malformation that more commonly occurs in the left lung, mainly near the lower mediastinum. It is rarely observed in patients with extralobar sequestration in adulthood. We report the case of a 55-year-old man with recurrent fever and cough lasting for about 1 month, who was admitted to our hospital. His past history was unremarkable. The final diagnosis of extralobar sequestration was dependent on three-dimensional computed tomography angiography (3D CTA), which showed an abnormal blood supply vessel to the consolidation from the aortic arch. The patient underwent a left pulmonary sequestration resection, and the pathological examination also verified the diagnosis postoperatively. 3D CTA images can provide an aberrant vessel anatomy map for the surgeon and play a decisive role in the detection of pulmonary sequestration.

The anatomical study of the corona mortis artery on three-dimensional computerized tomography angiography and its clinical significance

Objective To investigate the incidence and location of the corona mortis artery by means of three dimensional (3D) reconstruction of computerized tomography angiography (CTA) as well as the clinical significance of the knowledge in the treatment of pelvic and acetabular fractures via ilioinguinal and Stoppa approaches.Methods Radiological and clinical data from 80 patients (160 hemi-pelvises) undergoing aorta abdominalis CTA between Deeember 2010 and May 2012 were collected.This study involved 34 males and 46 females,aged from 19 to 84 years (average,47.2 years).The.dicom format CTA data were used for 3D reconstruction using the Mimics software.The incidence and origin of the corona mortis artery crossing the superior pubic ramus into the obturator foramen were observed and the distances between the corona mortis artery and the pubic symphysis were measured on the 3D reconstruction images.The incidences were compared between hemi-pelvises,genders and age groups of ≤50 and ＞ 50 years.Results In the 160 hemi-pelvises,altogether 29 corona mortis arteries were detected,giving a total incidence of 18.1％ (29/160).Of them,14(14/80,17.5％) were found on the left side and 15 (15/80,18.8％) on the right; 16(16/92,17.4％) in the female patients and 13 (13/68,19.1％) in the male patients; 14 (14/98,14.3％) in the ≤50 age group and 15(15/62,24.2％) in the ＞ 50 age group.There were no significant differences regarding the incidence between hemi-pelvises,genders or age groups (P ＞ 0.05).The distances between the corona mortis artery and the pubic symphysis averaged 53.70 ±4.00 mm.Conclusions Since CTA 3D reconstruction images can clearly demonstrate the corona mortis artery,abdominal aorta CTA should be recommended before operative treatment of pelvic and acetabular fractures via the ilioinguinal and Stoppa approaches to make sure that no operative accident will occur due to presence of the corona mortis artery.We should be alert to this artery variation when stripping the suprapubic area 53.70 ± 4.00 mm to the edge of the pubic symphysis. Key words: Artery; Imaging, three-dimensional; Anatomy

Image fusion for hybrid repair of dislocated superior mesenteric branch of a branched endovascular aortic graft

Recent advances in imaging technology allow the projection of volumetric imaging data from the preacquired computed tomography angiography over live fluoroscopy during interventions. This "fusion" technology is currently underused, although its application carries distinct advantages. We introduce a case in which fusion technology was used for the placement of two thoracic and one branched abdominal aortic endograft and to treat late dislocation of its side branch using a hybrid technique.

Abstract WMP30: Risk Analysis Of Growth And Rupture In Unruptured Intreacranial Aneurysms : Single Institutional Cohort Study

Introduction: Risk of growth and rupture in unruptured intracranial saccular aneurysm (UIA) are still unclear. Hypothesis: Gowth and risk of UIA may be correlated and they were evaluated our single center large cohort. Methods: Between January 2003 and March 2011, a total of 2122 patients with 2756 UIA were referred to our institution. 1403 patients with 2037 UIAs were assigned for conservative management. The mean follow up duration was 6201 aneurysm-years. Bi-annual three-dimensional computed tomography angiography (3D CTA) was performed and aneurysm growth was evaluated using 3D workstation. The aneurysm growth was defined as size increase more than 1mm. Results: During observation, 14.6% aneurysms increased their size. Female and male growth rate were 16% and 11% respectively. 130 patients stopped observation and therapeutic intervention was performed due to increase their size or anxiety. During observation 50 UIAs ruptured resulting in a 0.8% rupture rate per year. Aneurysm growth, IC-pcom aneurysms, posterior circulation, female, and SAH associated multiple aneurysms were risk factor for aneurysm rupture. Growing aneurysm was 10 times higher relative risk of rupture compare to stable aneurysm. No aneurysm demonstrated reduction of their size after rupture. Conclusions: Risk of Aneurysm growth and rupture may be correlated. Risk of rupture of UIAs was similar that was reported before but even small aneurysms can be rupture during observation. Growing UIAs should be considered to treat as soon as possible even in small size.

Posterior Fixation for Atlantoaxial Subluxation in a Case With Complex Anomaly of Persistent First Intersegmental Artery and Assimilation in the C1 Vertebra

We report a very rare case of atlantoaxial subluxation (AAS) with persistent first intersegmental artery (PFIA) and assimilation in the atlas (C1) vertebra. This case demonstrates the difficulty of deciding on a surgical strategy for complex anomalies. A 63-year-old man presented with gait disturbance, neck pain, and severe dysesthesia in his left arm. Past history included a whiplash injury. Dynamic X-ray studies demonstrated an irreducible AAS and assimilation of C1. This subluxation was slightly deteriorated in an extended position. A three-dimensional computed tomography angiography (3DCTA) indicated that the PFIA was located on the left side. We performed a C1 posterior arch resection and C1 lateral mass–axis pedicle screw (C1LM–C2PS) fixation using the modified technique of skewering the occipital condyle and C1 lateral mass. The patient had no postoperative morbidity and his symptoms disappeared immediately after operation. Complex anomalies cause difficulty in determining surgical strategy although several surgical methods for simple craniovertebral junction anomaly have been reported. To avoid significant morbidities associated with vertebral artery injury, surgical strategies for these complex conditions are discussed. The modified technique of a C1 lateral mass screw penetrating the occipital condyle is a viable treatment option.