Three-dimensional Computed Tomography Angiography Research Articles

Intraoperative assessment of anterior circulation aneurysms using the indocyanine green video angiography technique

We performed a prospective study to evaluate the intraoperative value of indocyanine green (ICG) video angiography in anterior circulation aneurysms. From January 2007 to April 2008, 42 patients with anterior circulation aneurysms who were to undergo aneurysm clipping were enrolled in the study. Intraoperative ICG video angiography was performed using a fluorescence microscope. After the operation, three-dimensional CT angiography (CTA), digital substraction angiography (DSA) and magnetic resonance angiography (MRA) were used to evaluate the use of intraoperative ICG video angiography. Of the 42 patients, on ICG video angiography after initial clip placement, neck remnants of the aneurysm were found in two patients, inadvertent clipping of branching vessels in one patient, and inadvertent clipping of perforating vessels in two patients. ICG video angiography after adjustment of the clip position showed a perfect residual elimination with no abnormal findings. Post-operative DSA, CTA and MRA results corresponded to the intraoperative ICG video angiography findings. Therefore, ICG video angiography is an important tool to monitor residual aneurysm, parent artery stenosis or perforating artery occlusion during intracranial aneurysm clipping.

Three-Dimensional Intravenous Digital Subtraction Angiography Using Flat Panel Detector System in Vascular Mapping of the External Carotid Artery: A Comparison with 3-Dimensional Computed Tomography Angiography

Super-selective intra-arterial infusion chemotherapy for head and neck cancer via the superficial temporal artery is an established procedure. Three-dimensional computed tomography angiography (3D-CTA) has often been used to assess the arterial anatomy. However, 3D-CTA images are sometimes affected by severe metallic artifacts near the oral cavity region, due to the presence of metallic dental materials. This study has evaluated 3-dimensional intravenous digital subtraction angiography (3D-IV-DSA) using a flat panel detector (FPD) system in vascular mapping of the external carotid artery (ECA), in comparison with 3D-CTA. To clarify the vascular anatomy of ECA branches, 15 patients had undergone both 3D-IV-DSA and 3D-CTA. The angiographic images of the ECA were generated using a volume-rendering technique. The 15 patients were also divided into two groups according to the existence of adverse effects due to dental metallic artifacts on 3D-CTA.Images from 3D-IVDSA were statistically significantly superior to 3D-CTA (P < 0.05). In particular, when metallic artifacts affected 3DCTA images, 3D-IV-DSA was able to depict the ECA more clearly. These findings confirm the utility of 3D-IV-DSA, and the technique may be particularly suitable for patients with metallic dental materials. Keywords: 3D-IV-DSA, rotational angiography, 3D-CTA, metallic artifacts, intra-arterial infusion chemotherapy, head and, neck cancer

Three-dimensional CT angiography simulates operative approaches for intracranial aneurysms

Three-dimensional CT angiography simulates operative approaches for intracranial aneurysms

The importance of vertebral artery proximity to the odontoid process during anterior odontoid approaches

The proximity of the vertebral artery (VA) to the odontoid process makes it vulnerable to injury during surgery. Knowledge of the quantitative anatomy of the VA groove is therefore necessary. In this study we assessed the spatial relationship between the VA and the odontoid process on cadavers by direct measurement and in patients by CT angiography. Our goal was to measure the distances from the VA and vertebrobasilar junction to the odontoid tip. The VA and odontoid process of 10 craniocervical cadavers (“cadavers”) and of 20 patients were evaluated and average measurements obtained. The measured parameters were: (i) distance from the right VA to the odontoid tip (right VA–odontoid tip); (ii) distance from the left VA to the odontoid tip (left VA–odontoid tip), and (iii) distance from the vertebrobasilar junction to the odontoid tip (vertebrobasilar–odotoid tip). On the cadavers, the right VA–odontoid tip distance was 11.55 mm, the left VA–odontoid tip was 11.02 mm, and the vertebrobasilar junction–odontoid tip distance was 24.55 mm. In patients, using CT angiography, the right VA–odontoid tip distance was 11.47 mm and the left VA–odontoid tip distance was 11.50 mm. The VA–odontoid tip distance is important in anterior odontoid approaches. Since the odontoid process may be in close contact with the VA, the relationship between them should be evaluated preoperatively in all candidates for odontoid surgery using three-dimensional CT angiography.

Bovine Aortic Arch in Association with Double Inlet Left Ventricle and Pulmonary Atresia: A Novel Association

We report a newborn male who was diagnosed with a double inlet left ventricle with pulmonary atresia antenatally. Postnatally, it was difficult to determine his arch anatomy echocardiographically. Therefore, he underwent three-dimensional computed tomography angiography, which confirmed the echocardiographic findings and demonstrated a bovine aortic arch. He additionally had a single coronary artery. To our knowledge, the association of a single ventricle with a single outlet of bovine morphology is novel.

Radiation dose reduction in time-resolved CT angiography using highly constrained back projection reconstruction

Recently dynamic, time-resolved three-dimensional computed tomography angiography (CTA) has been introduced to the neurological imaging community. However, the radiation dose delivered to patients in time-resolved CTA protocol is a high and potential risk associated with the ionizing radiation dose. Thus, minimizing the radiation dose is highly desirable for time-resolved CTA. In order to reduce the radiation dose delivered during dynamic, contrast-enhanced CT applications, we introduce here the CT formulation of HighlY constrained back PRojection (HYPR) imaging. We explore the radiation dose reduction approaches of both acquiring a reduced number of projections for each image and lowering the tube current used during acquisition. We then apply HYPR image reconstruction to produce image sets at a reduced patient dose and with low image noise. Numerical phantom experiments and retrospective analysis of in vivo canine studies are used to assess the accuracy and quality of HYPR reduced dose image sets and validate our approach. Experimental results demonstrated that a factor of 6–8 times radiation dose reduction is possible when the HYPR algorithm is applied to time-resolved CTA exams.

Endoscopically-assisted resection of a cystic lymphangioma in an adult

We report endoscopically-assisted resection of a cystic lymphangioma in an adult. A 40-year-old female with a cervical swelling was referred to our department. Three-dimensional computed tomography angiography (3D-CTA) was done preoperatively to assess the extent and vascularity of the lesion. We planed endoscopically-assisted resection of cystic lymphangioma as a minimally invasive approach because of multi cystic type. Under general anaesthesia, a 2-cm long skin incision was made in a natural wrinkle just over the centre of the protruding area sufficient to introduce the instruments.

Results of Endovascular Repair of Abdominal Aortic Aneurysms with an Unfavorable Proximal Neck Using Large Stent-Grafts

The purpose of this study was to evaluate the early outcome of endovascular repair of abdominal aortic aneurysms (EVAR) with an unfavorable neck anatomy using extralarge stent-grafts. We carried out a retrospective review of all patients who underwent elective EVAR using large diameter stent-grafts between June 2006 and February 2008. All patients had computed tomography angiography (CTA) for procedure planning, and detailed assessment of the aneurysm neck was performed using a three-dimensional CTA workstation. All patients were followed up with CTA at 3 and 12 months and annual duplex thereafter when appropriate. This analysis included 25 patients (23 men, 2 woman; median age, 76 years; age range, 60-88 years). The median aneurysm diameter was 7 cm, and the median aneurysm neck diameter was 31 mm. Extralarge Cook-Zenith stent-grafts were used in all patients, with a top-end diameter of 36 mm (n=23) and 40 mm (n=2). The follow-up period ranged from 3 to 24 months, with a median of 6 months. Primary and assisted primary technical success rates were 80% and 96%, respectively. Reintervention was required to treat proximal type I endoleak (n=1), iliac limb kink (n=2), and occluded femorofemoral crossover graft (n=1). These early results show that EVAR using extralarge stent-grafts with suprarenal fixation can be a reliable modality to treat infrarenal aortic aneurysms with an unfavorable neck anatomy.

Imaging anatomy and variation of vertebral artery and bone structure at craniocervical junction

The objective of this article is to display the vertebral artery and bone structure at the craniocervical junction (CJVA and C(0-1-2)) with three-dimensional CT angiography (3DCTA) and identify their anatomic features and variations. Eighty-eight subjects without pathology of vertebral artery (VA) and C(0-1-2) were selected from head-neck CTA examination. 3D images were formed with volume rendering (VR) and multiplanar reconstruction (MPR). On the 3D images, CJVA and C(0-1-2) were measured, and their variations were observed. CJVA goes along C(0-1-2) with five curves, of which three curves are visibly away from C(0-1-2), one is 0.0-8.3 mm away at the second curve with 0.0-11.2 mm in width, another is 0.0-9.2 mm away at the fourth with 2.8-14.8 mm and the other is 0.0-6.2 mm away at the fifth. Statistical comparisons show that there is no significant difference in the measurements between left and right, and that the curves become smaller and farther away from C(0-1-2) with the increase of age. CJVA is not equal in size, with the biggest in the fourth curve and the smallest in the fifth. Statistical comparison shows the left CJVA is larger than the right in the fifth curve. Variations were found on CJVA in 16 cases and on C(1) in 12 cases. The anatomy and variations of CJVA and C(0-1-2) are complicated. It is of vital significance to identify their anatomic features in clinical practice.

Evaluation of Clip Artefacts in Three-dimensional Computed Tomography

Recently, three-dimensional CT angiography (3D-CTA) has been used as a diagnostic method in postoperative evaluation after aneurysm clipping. A systematic analysis of possible predictors for good image quality needs to be conducted if 3D-CTA is to replace digital subtraction angiography in the postoperative setting. The aim of this study was to evaluate the influence of clip orientation on image quality and to assess titanium clip artefacts quantitatively on 3D-CTA. Four different Yasargil titanium clips were placed on an acrylic glass tablet. Standardised 3D-CTA scanning was performed at clip-gantry angles of 0 degrees , 45 degrees and 90 degrees . Multiplanar reconstructions of the clips in frontal and lateral projections were performed. 3D-CTA image quality and the severity of titanium artefacts were judged by four observers. Twenty-four images were evaluated. Using frontal reconstructions, clip artefacts at a clip-gantry angle of 0 degrees were almost exclusively distributed along the long axis of the clip, with excellent evaluation quality at the lateral side of the clip branches. With decreasing clip-gantry angle (90 degrees and 45 degrees ) strong artefacts were localised laterally. On lateral reconstructions image quality was not significantly more restricted, regardless of the clip-gantry angles used. 3D-CTA image quality can be severely limited by clip artefacts. The expression and distribution of these artefacts depends on both the clip-gantry angle and the plane of image reconstruction. Overall, there is no correlation between clip-gantry angle and either the severity or the spatial distribution of clip artefacts leading to observable restrictions in the evaluation of surrounding structures.

Follow-up study on in-stent thrombosis after carotid stenting using multidetector CT angiography

The purpose of the present study was to evaluate the role of multidetector three-dimensional computed tomography angiography (3D CTA) for evaluating both the residual arterial lumen and the sequential change in the intraluminal diameter and thrombus formation following carotid artery stenting (CAS). Twenty consecutive patients consisting of 23 successfully stented carotid arteries were examined by 3D CTA with volume-rendering at 2, 4, 8, 12 weeks and 6, 12 months of follow-up. The eccentric in-stent hypodense area could be detected in ten of 23 (43.5%) carotid arteries at 2 weeks of follow-up, and they then gradually declined until they almost disappeared at 12 weeks. Eccentric in-stent hypodense areas in the acute and subacute phase (up to 12 weeks after CAS) were found in nine out of 16 carotid arteries with longer stents (3 or 4 cm in size) deployed across the carotid bifurcation, whereas no eccentric in-stent hypodense area could be observed in the patients with a short stent (2 cm) deployed only to the internal carotid artery. Seven of the ten observed eccentric hypodense areas presented on the dorsal surface at the carotid bifurcation level. Carotid 3D CTA for evaluating residual lumen and in-stent thrombus formation after CAS is considered to be a useful diagnostic method. To avoid stent occlusion, both the acute and subacute phases following CAS (up to 12 weeks) call for the administration of appropriate anti-platelet therapy and careful observations of the patients.

Three-dimensional computed tomography angiography in presurgical planning for treatment of infratentorial dural arteriovenous fistulas

Dural arteriovenous fistulas (DAVFs) with pure leptomeningeal drainage may be cured by simple interruption of their venous side. This report illustrates the cases of 3 patients undergoing surgery for fistulas classified as Borden Type III, involving the posterior cranial fossa. Preoperatively, the surgical anatomy of these lesions was investigated with 3D reformatting of multislice CT angiography, in addition to conventional angiography. Reformatted images clarified the surgical anatomy of the malformation. Reconstructing both the osseous and the vascular structures and simulating the surgical orientation allowed localization of the dural takeoff point of the DAVF's drainage, showing its relationship with osseous landmarks. Precise localization of the DAVF's drainage may help in choosing the most direct and effective approach to treat the malformation. The reported cases could be treated with a standard retrosigmoid exposure, avoiding the need for more complex cranial base approaches.

Anterior Spinal Artery as a Collateral Channel in Patients With Acute Bilateral Vertebral Artery Occlusions -Two Case Reports-

Retrograde flow through the anterior spinal artery (ASA) from the cervical vertebral artery (VA) to the intracranial distal VA due to disrupted perfusion caused by bilateral VA occlusion is rare. We report two cases of hemodynamic vertebrobasilar circulatory insufficiency caused by bilateral VA occlusion. In these patients, the ASA filled in the retrograde direction, and provided collateral support to the ipsilateral posterior inferior cerebellar artery. The patients were treated with drip intravenous infusion of edaravone and/or argatroban. One patient had a good collateral supply from the posterior communicating artery and recovered almost completely within one month, but the other did not and lapsed into a coma, with generalized hyperreflexia, pin-point pupils, and ataxic respiration. Severe calcified lesions on three-dimensional computed tomography angiography at the occlusion site in the second patient indicated direct surgery including right superficial temporal artery to superior cerebellar artery anastomosis, rather than the endovascular approach. Retrograde flow through the ASA may be observed in this type of critical situation, and may be an important source of collateral supply to the posterior fossa territory.

Coil Embolization of an Unruptured Intracranial Aneurysm Associated With Behcet's Disease -Case Report-

A 36-year-old male patient with Behcet's disease consulted our hospital for treatment of an unruptured intracranial aneurysm. He was neurologically intact. He had undergone surgery for an aneurysm of the superior mesenteric artery 2 years ago and had been followed up because of the aneurysm of the left radial artery for 1 year. He had been receiving steroid treatment for 4 years. Three-dimensional computed tomography angiography identified an aneurysm of the left intracranial internal carotid artery. The lesion was treated by coil embolization. He was discharged without complications. Intracranial aneurysm formation is extremely rare in patients with Behcet's disease. The presence of extracranial aneurysms indicates screening for intracranial aneurysms. The present case shows that coil embolization can be used to treat unruptured intracranial aneurysm in patients with Behcet's disease.

Hemorrhagic Infarction Originating From Vertebral Artery Stenosis Caused by an Osteophyte at the C5 Superior Articular Process -Case Report-

A 62-year-old man presented with right upper homonymous quadrihemianopsia. Magnetic resonance imaging showed hemorrhagic infarctions in the bilateral occipital lobes and infarction in the left cerebellar hemisphere. Digital subtraction angiography and three-dimensional computed tomography angiography revealed right vertebral artery (VA) stenosis caused by an osteophyte at the C5 superior articular process. The VA stenosis was aggravated by neck extension. The brain infarctions were attributed to embolism from the right VA stenosis. Unroofing of the anterior root of the right C4 transverse foramen, removal of the osteophyte at the superior articular process of C5, and anterior fusion at C4-5 were performed. His postoperative course was uneventful.

Extent of Aortic Coverage and Incidence of Spinal Cord Ischemia After Thoracic Endovascular Aneurysm Repair

Risk factors for spinal cord ischemia (SCI) after thoracic endovascular aneurysm repair (TEVAR) remain unclear. Aortic coverage was examined as a risk factor for SCI using quantitative three-dimensional computed tomography angiography (CTA) analysis. The medical records, radiographic imaging studies, and a prospectively maintained database of all TEVAR procedures performed during a 7-year period were retrospectively reviewed. Preoperative anatomic dimensions and postoperative graft path lengths were measured from CTAs using curved planar and orthogonal multiplanar reformations along centerline paths. SCI was defined as transient or permanent lower extremity neurologic deficit without associated intracerebral hemispheric events. Of 326 TEVAR cases, 241 patients (74%) had satisfactory imaging. Thirty-three (10%) had SCI. These patients were older (72.7 +/- 10.6 vs 64.7 +/- 15.8 years, p = 0.005) and had longer intraoperative procedure times (137 +/- 65 vs 113 +/- 68 minutes, p = 0.05). Despite similar total lengths of native thoracic aorta (295.0 +/- 36.3 vs 283.1 +/- 39.8 mm, p = 0.17), patients with permanent SCI had a greater absolute (260.5 +/- 40.9 vs 195.8 +/- 81.6 mm, p = 0.002) and proportionate (88.8% +/- 12.1% vs 67.6% +/- 24.0%, p = 0.001) length of aortic coverage. The average length of uncovered aorta proximal to the celiac artery in patients with SCI was 17.3 +/- 21.8 mm vs 63.1 +/- 62.9 mm in patients without SCI (p = 0.0006). Neither the patency of the hypogastric arteries nor left subclavian artery was associated with SCI. The extent and distal location (relative to the celiac artery) of aortic coverage were associated with an increased risk of SCI. Prophylactic measures for spinal cord protection should be considered in patients whose thoracic aortas require extensive coverage.

Bolus injection of contrast agents with various iodine concentrations and delivery rates for intracranial three-dimensional CT angiography: evaluation of intracranial arteriovenous contrast using a multidetector-row CT scanner

We evaluated the difference in computed tomography (CT) attenuation values of the intracranial arterial and venous systems among the various contrast injection protocols (higher iodine delivery rate or higher concentration of the agent) on the source images of intracranial three-dimensional CT angiography (3D-CTA) using a multidetector-row CT (MDCT) scanner. We used 100 ml of iopamidol 300 at an injection rate of 3.0 ml/s, 100 ml of iopamidol 300 at an injection rate of 3.7 ml/s, and 80 ml of iopamidol 370 at an injection rate of 3.0 ml/s. There were 10 patients in each group. Attenuation values of the bilateral internal carotid arteries (ICAs), basilar artery trunk, bilateral cavernous sinuses (CSs), and Galenic vein were measured quantitatively on the axial CT angiographic source images obtained by four-channel MDCT. Injection of the high-concentration contrast with a higher iodine-delivery rate achieved good arteriovenous contrast at the cavernous portion. With the same rate of iodine delivery, injection of the intermediate concentrate agent increased the CT value of not only the ICAs but also the CSs. High-concentration contrast could increase ICA attenuation without intracavernous attenuation gain during the "first-pass" phase.

An 8-year-old boy with vertebral artery dissection with cerebellar ataxia featuring suspected vertebral artery hypoplasia

We report an 8-year-old boy with left vertebral artery dissection featuring cerebellar ataxia in which congenital vertebral artery hypoplasia was suspected as a predisposing factor in the dissection. The patient suddenly suffered from vertigo and vomiting while swimming, and he was brought to our department. The initial brain Computed Tomography (CT) demonstrated no abnormalities, and his symptoms disappeared the next morning. However, one month after onset, brain Magnetic Resonance Imaging (MRI) revealed ischemic changes (infarction) in the left cerebellum. Transfemoral angiography showed complete occlusion at the C2 portion of the left vertebral artery, suggesting dissection and diffuse narrowing of the proximal segment of the occlusion site. Three-dimensional CT angiography also revealed diffuse narrowing of the left vertebral artery from the bifurcation of the subclavian artery. He has since been living daily life without any difficulties. The detailed etiology of cerebral artery dissection remains unknown, but arterial anomalies should be considered as a predisposing factor.

Three-Dimensional Computed Tomographic Findings of Bilateral Tracheal Bronchus

A newborn male was admitted with cyanosis and respiratory distress. Echocardiography showed a right heart isomerism associated with a single right ventricle, a double-outlet right ventricle, and pulmonary atresia. Chest X-ray demonstrated severe left upper lobe emphysema and a shift of the mediastinal structures to the right. Two-dimensional computed tomography (CT) exhibited left upper lobe emphysema and right upper lobe atelectasis. Three-dimensional (3D) spiral CT angiography showed a bilateral tracheal bronchus. The left tracheal bronchus branch was compressed between the descending aorta and the ductus arteriosus. After a right arteriopulmonary shunt operation, the patient's respiratory condition improved dramatically, with spontaneous closure of the ductus arteriosus. Subsequently, 3D-CT clearly exhibited the disappearance of tracheal compression. This combination of bilateral tracheal bronchus and congenital heart anomaly is extremely rare. The 3D-CT is a powerful noninvasive means for dynamically demonstrating the special relationships of arterial and tracheal anomalies.

Posterolateral protrusion of the vertebral artery over the posterior arch of the atlas: quantitative anatomical study using three-dimensional computed tomography angiography

The vertebral artery (VA) often takes a protrusive course posterolaterally over the posterior arch of the atlas. In this study, the authors attempted to quantify this posterolateral protrusion of the VA. Three-dimensional CT angiography images obtained for various cranial or cervical diseases in 140 patients were reviewed and evaluated. Seven patients were excluded for various reasons. To quantify the protrusive course of the VA, the diameter of the VA and 4 parameters were measured in images of the C1-VA complex obtained in the remaining 133 patients. The authors also checked for anomalies and anatomical variations. When there was no dominant side, mean distances from the most protrusive part of the VA to the posterior arch of the atlas were 6.73 +/- 2.35 mm (right) and 6.8 +/- 2.15 mm (left). When the left side of the VA was dominant, the distance on the left side (8.46 +/- 2.00 mm) was significantly larger than that of the right side (6.64 +/- 2.0 mm). When compared by age group (< or = 30 years, 31-60 years, and > or = 61 years), there were no significant differences in the extent of the protrusion. When there was no dominant side, the mean distances from the most protrusive part of the VA to the midline were 30.73 +/- 2.51 mm (right side) and 30.79 +/- 2.47 mm (left side). When the left side of the VA was dominant, the distance on the left side (32.68 +/- 2.03 mm) was significantly larger than that on the right side (29.87 +/- 2.53 mm). The distance from the midline to the intersection of the VA and inner cortex of the posterior arch of the atlas was approximately 12 mm, irrespective of the side of VA dominance. The distance from the midline to the intersection of the VA and outer cortex of the posterior arch was approximately 20 mm on both sides. Anatomical variations and anomalies were found as follows: bony bridge formation over the groove for the VA on the posterior arch of C-1 (9.3%), an extracranial origin of the posterior inferior cerebellar artery (8.2%), and a VA passing beneath the posterior arch of the atlas (1.8%). Conclusions There may be significant variation in the location and branches of the VA that may place the vessel at risk during surgical intervention. If concern is noted about the vulnerability of the VA or its branches during surgery, preoperative evaluation by CT angiography should be considered.