3D Angiography Images Research Articles

Calculation of virtual 3D subtraction angiographies using conditional generative adversarial networks (cGANs)

ObjectiveSubtraction angiographies are calculated using a native and a contrast-enhanced 3D angiography images. This minimizes both bone and metal artifacts and results in a pure image of the vessels. However, carrying out the examination twice means double the radiation dose for the patient. With the help of generative AI, it could be possible to simulate subtraction angiographies from contrast-enhanced 3D angiographies and thus reduce the need for another dose of radiation without a cutback in quality. We implemented this concept by using conditional generative adversarial networks.MethodsWe selected all 3D subtraction angiographies from our PACS system, which had performed between 01/01/2018 and 12/31/2022 and randomly divided them into training, validation, and test sets (66%:17%:17%). We adapted the pix2pix framework to work on 3D data and trained a conditional generative adversarial network with 621 data sets. Additionally, we used 158 data sets for validation and 164 for testing. We evaluated two test sets with (n = 72) and without artifacts (n = 92). Five (blinded) neuroradiologists compared these datasets with the original subtraction dataset. They assessed similarity, subjective image quality, and severity of artifacts.ResultsImage quality and subjective diagnostic accuracy of the virtual subtraction angiographies revealed no significant differences compared to the original 3D angiographies. While bone and movement artifact level were reduced, artifact level caused by metal implants differed from case to case between both angiographies without one group being significant superior to the other.ConclusionConditional generative adversarial networks can be used to simulate subtraction angiographies in clinical practice, however, new artifacts can also appear as a result of this technology.

Basilar Artery Perforator Aneurysms - The Phantom Menace of the Intracranial Universe.

Cerebral perforators are end-arteries that vascularize specific deep territories in the cerebral hemispheres and brainstem. Due to improved imaging quality, these aneurysms are increasingly diagnosed in clinical routine. High resolution 3D angiographic images are mandatory and in some occasions fusion images might be helpful to detect these aneurysms. Basilar artery perforator aneurysms (or BAPAs) are one of the most common subtypes of perforator aneurysms and might cause subarachnoid hemorrhage along the brainstem (perimesencephalic hemorrhage). Due to the limited evidence, the management of BAPAs may pose a challenge in clinical routine. While some aneurysms can be managed conservatively, a few might require treatment to prevent rebleeding. We present the cases of two patients with BAPAs managed at our center in order to increase the awareness on these potentially underdiagnosed aneurysms.

Physics-Informed Neural Networks for Brain Hemodynamic Predictions Using Medical Imaging.

Determining brain hemodynamics plays a critical role in the diagnosis and treatment of various cerebrovascular diseases. In this work, we put forth a physics-informed deep learning framework that augments sparse clinical measurements with one-dimensional (1D) reduced-order model (ROM) simulations to generate physically consistent brain hemodynamic parameters with high spatiotemporal resolution. Transcranial Doppler (TCD) ultrasound is one of the most common techniques in the current clinical workflow that enables noninvasive and instantaneous evaluation of blood flow velocity within the cerebral arteries. However, it is spatially limited to only a handful of locations across the cerebrovasculature due to the constrained accessibility through the skull's acoustic windows. Our deep learning framework uses in vivo real-time TCD velocity measurements at several locations in the brain combined with baseline vessel cross-sectional areas acquired from 3D angiography images and provides high-resolution maps of velocity, area, and pressure in the entire brain vasculature. We validate the predictions of our model against in vivo velocity measurements obtained via four-dimensional (4D) flow magnetic resonance imaging (MRI) scans. We then showcase the clinical significance of this technique in diagnosing cerebral vasospasm (CVS) by successfully predicting the changes in vasospastic local vessel diameters based on corresponding sparse velocity measurements. We show this capability by generating synthetic blood flow data after cerebral vasospasm at various levels of stenosis. Here, we demonstrate that the physics-based deep learning approach can estimate and quantify the subject-specific cerebral hemodynamic variables with high accuracy despite lacking knowledge of inlet and outlet boundary conditions, which is a significant limitation for the accuracy of the conventional purely physics-based computational models.

Evaluation of the SYNAPSE VINCENT for lateral lymph node dissection in rectal cancer with robotic surgery: a preliminary report

BackgroundEven if 3D angiographic images of preoperative contrast-enhanced computed tomography (CT) are created, the coronal and axial sections can be unclear, and thus, it is difficult to achieve projection awareness similar to that of actual laparoscopic images. In recent years, the technology of analyzing and applying medical images has advanced, and surgical simulation and navigation have been widely used to improve the safety of surgical operations. It is important to understand pelvic anatomy in the area of rectal cancer, and use of the SYNAPSE VINCENT makes it possible to simulate the anatomy before surgery, which is very useful in educating surgeons and their assistants.Materials and methodsAn important objective in surgery is to understand the anatomy of the external/internal iliac arteries and lymph nodes in lateral lymph node dissection (LLD) for rectal cancer. In this study, we explored the accuracy and usefulness of SYNAPSE VINCENT images of pelvic anatomy (especially vascular anatomy) analyzed preoperatively in two cases of LLD for rectal cancer in our department.ResultsThe patients were two men aged 73 and 57 years, respectively. Both patients underwent robotic abdominal perineal resection and LLD with neoadjuvant chemoradiotherapy. The operating times for LLD were 138 and 106 min, estimated blood loss was less than 10 mL and 20 mL, and the harvested lymph nodes were nos. 21 and 22, respectively. The SYNAPSE VINCENT could be used for simulation and navigation before and during surgery. For experienced surgeons, the system helped them carry out operations more accurately.ConclusionIn the future, surgical support using virtual reality, augmented reality, and mixed reality based on medical images will be useful and is expected to improve the safety, accuracy, and efficiency of surgery, which is extremely useful for both young and skilled surgeons preparing for difficult operations.

Points to consider when evaluating three-dimensional digital subtraction angiography of intracranial aneurysms and their effects on treatment

Background/aimIn this study, we aimed to investigate what should be regarded as potential determinants of treatment strategies when evaluating 3D digital subtraction angiography (DSA) images.Material and methodsOur inclusion criteria were as follows: (1) presence of at least one intracranial aneurysm demonstrated by conventional angiography, (2) having both 2D and 3D images, and (3) being over 18 years old. First, two-dimensional (2D) and then 3D angiography images of 226 aneurysms of 150 patients were scanned. Morphological characteristics such as size, configurations, relationship with parent artery, baby counts, and other incidental findings were determined.ResultsOf the 226 aneurysms, 11 (4.9%) were only detected on 3D images. Four of these 11 additional aneurysms were believed to be babies of other aneurysms seen in 2D images. Middle cerebral artery (MCA) M1 segment was the most common localization in terms of missed aneurysms. Of the 28 aneurysms located in the communicating segment of the internal carotid artery, the absolute locations of 7 (25%) could not be detected in 2D images or detected in the wrong location. Of the 24 aneurysms located in the ophthalmic segment, the origin of 8 (33%) could not be clearly identified in 2D images. Truncus relationships of MCAs bifurcation/trifurcation aneurysms were seen in 41 of 63 aneurysms (65%) on 2D images, whereas all were confirmed on 3D images. Fenestrations not seen in 2D images were identified in 3D images of 4 patients (3%).ConclusionThe superiority of 3D images compared to 2D images in determining the morphologic characteristics of intracranial aneurysms has been known for a long time. The contribution of 3D images to the treatment can be summarized as evaluating the parent artery relationship, revealing the number and shapes of aneurysm babies more clearly, detecting fenestrations, and shortening procedure time by finding the correct working angle.

Blebs in intracranial aneurysms: prevalence and general characteristics

BackgroundBlebs are rupture risk factors in intracranial aneurysms (IAs), but their prevalence, distribution, and associations with clinical factors as well as their causes and effects on aneurysm vulnerability remain unclear.MethodsA...

Radiation dose reduction for 3D angiography images in pediatric and congenital cardiology.

The purpose of this study was to investigate the influence of simulated reduced-dose three-dimensional angiography (3DA) on the accuracy and precision of linear measurements derived from 3DA datasets. Three-dimensional angiography is performed during X-ray guided interventional procedures to aid diagnosis and inform treatment strategies for children and adults with congenital heart disease. However, 3DA contributes substantially to patient radiation dose and may lead to an increased radiation-induced cancer risk. Reduced-dose patient 3DA images were simulated by adding quantum noise to the 2D projection angiograms, then reconstructing the projection angiograms into the 3DA dataset. Dose reduction in the range 33-72% was simulated. Five observers performed 46 vessel diameter measurements along prespecified axes within 23 vessel segments from 11 patient 3DA datasets. Statistical tests were performed to assess the influence of radiation dose reduction on the accuracy and precision of vessel diameter measurements. Vessel diameter measurements were in the range 5.9- 22.7 mm. Considering all vessel segments and observers, the influence of dose level on the accuracy of diameter measurements was in the range 0.02 - 0.15 mm (p .05-.8). Interobserver variability increased modestly with vessel diameter, but was not influence by dose level (p = .52). The statistical test for observer recall bias was negative (p = .51). Simulated dose reduction up to 72% did not affect the accuracy or precision of the diameter measurements acquired from 3DA images. These findings may embolden 3DA radiation dose reduction for pediatric and congenital heart disease patients.

Are hemodynamics of irregular small carotid-ophthalmic aneurysms different from those of regular ones and large aneurysms based on numerical simulation?

The purpose of this study is to investigate whether hemodynamics of unruptured, irregular small intracranial aneurysms (SIAs) are different from those of regular ones and large intracranial aneurysms (LIAs) in ophthalmic artery segment of internal carotid artery (ICA). Between April 2015 and June 2018, 106 carotid-ophthalmic artery aneurysms were retrospectively analyzed using 3D angiographic images and computational fluid dynamics (CFD). Three categories were stratified: regular SIAs, irregular SIAs and LIAs. Statistical comparisons of the differences in clinical, morphological and hemodynamic parameters among regular SIA, irregular SIA and LIA groups were performed by one-way analysis of variance (ANOVA) or Kruskal-Wallis Test. The median maximal height of regular SIA, irregular SIA and LIA were 3.03 (interquartile range: 2.49-4.22) mm, 4.59 (interquartile range: 3.86-5.32) mm and 11.06 (interquartile range: 9.28-13.69) mm, all P < 0.05). Low shear-stress area percentage (LSA%) and oscillatory shear index (OSI) of irregular SIAs and LIAs were not significantly different (P = 0.72, P = 0.27 respectively), and were significantly higher than those of regular SIAs (all P < 0.01). Wall shear stress (WSS) and normalized wall shear stress (NWSS) of irregular SIAs were significantly higher than those of LIAs (P < 0.01, P < 0.01 respectively), but lower than those of regular SIAs (P < 0.01, P < 0.01 respectively). Special unruptured irregular SIAs share a similarity of hemodynamic characteristics with LIAs in high LSA% and high OSI, and are different from regular SIAs in hemodynamics.

Effective accuracy of stereoelectroencephalography: robotic 3D versus Talairach orthogonal approaches.

Stereoelectroencephalography (SEEG) was first developed in the 1950s by Jean Talairach using 2D angiography and a frame-based, orthogonal approach through a metallic grid. Since then, various other frame-based and frameless techniques have been described. In this study the authors sought to compare the traditional orthogonal Talairach 2D angiographic approach with a frame-based 3D robotic procedure that included 3D angiographic interoperative imaging guidance. MRI was used for both procedures during surgery, but MRI preplanning was done only in the robotic 3D technique. All study patients suffered from drug-resistant focal epilepsy and were treated at the same center by the same neurosurgical team. Fifty patients who underwent the 3D robotic procedure were compared to the same number of historical controls who had previously been successfully treated with the Talairach orthogonal procedure. The effectiveness and absolute accuracy, as well as safety, of the two procedures were compared. Moreover, in the 3D robotic group, the reliability of the preoperative MRI to avoid vascular structures was evaluated by studying the rate of trajectory modification following the coregistration of the intraoperative 3D angiographic data onto the preoperative MRI-based trajectory plans. Effective accuracy (96.5% vs 13.7%) and absolute accuracy (1.15 mm vs 4.00 mm) were significantly higher in the 3D robotic group than in the Talairach orthogonal group. Both procedures showed excellent safety results (no major complications). The rate of electrode modification after 3D angiography was 43.8%, and it was highest for frontal and insular locations. The frame-based, 3D angiographic, robotic procedure described here provided better accuracy for SEEG implantations than the traditional Talairach approach. This study also highlights the potential safety advantage of trajectory planning using intraoperative frame-based 3D angiography over preoperative MRI alone.

Prediction of restenosis based on hemodynamical markers in revascularized femoro-popliteal arteries during leg flexion

Endovascular therapy in patients suffering from peripheral arterial disease shows high rates of restenosis. The poor clinical outcomes are commonly explained by the demanding mechanical environment due to leg movements, but the mechanisms responsible for restenosis remain unknown. In this study, we hypothesized that restenosis following revascularization is associated with hemodynamical markers derived from blood flow during leg flexion. Therefore, we performed personalized computational fluid dynamics (CFD) analyses of 20 patients, who underwent routine endovascular femoro-popliteal interventions. The CFD analyses were conducted using 3D models of the arterial geometry in straight and flexed positions, which were reconstructed from 2D angiographic images. Based on restenosis rates reported at 6-month follow-up, logistic regression analyses were performed to predict restenosis from hemodynamical parameters. Results showed that severe arterial deformations, such as kinking, induced by leg flexion in stented arteries led to adverse hemodynamic conditions that may trigger restenosis. A logistic regression analysis based solely on hemodynamical markers had an accuracy of 75%, which showed that flow parameters are sufficient to predict restenosis (p = 0.031). However, better predictions were achieved by adding the treatment method in the model. This suggests that a more accurate image acquisition technique is required to capture the localized modifications of blood flow following intervention, especially around the stented artery. This approach, based on the immediate postoperative configuration of the artery, has the potential to identify patients at increased risk of restenosis. Based on this information, clinicians could take preventive measures and more closely follow these patients to avoid complications.

Fluoroscopy with MRA fusion image guidance in endovascular iliac artery interventions: study protocol for a randomized controlled trial (3DMR-Iliac-roadmapping study)

BackgroundEndovascular iliac artery interventions rely on the use of two-dimensional digital subtraction angiographies with an iodinated contrast agent and ionizing radiation. The amount of iodinated contrast agent should be limited because of its potentially nephrotoxic effects. Three-dimensional (3D) image fusion requires registration of a preprocedural magnetic resonance angiogram (MRA) or computed tomography (CT) angiogram to a perprocedurally acquired cone-beam CT or two fluoroscopic orthogonal projections. After registration, the 3D angiography images can be overlaid on the fluoroscopy screen and will follow table and C-arm movements. This study will assess the added value of the 3D image fusion technique in iliac artery interventions regarding the amount of the iodinated contrast agent administered.Methods/DesignThe study cohort will comprise 106 patients (> 18 years) with symptomatic common and/or external iliac artery stenoses or occlusions and a recent (< 6 months) diagnostic MRA from the pelvis through the lower extremities, for which an endovascular intervention is indicated. Patients will be randomized into the control or study group (i.e. treatment without or with 3D image fusion guidance). The primary endpoint is the amount of administered iodinated contrast agent (mL). Secondary outcomes are technical success of the procedure, defined as < 30% residual stenosis over the treated lesion, fluoroscopy time, and radiation dose as dose area product (mGycm2). Patient participation in the study will be completed after hospital discharge.DiscussionThis study is a randomized controlled multicenter trial to provide evidence on the effect of the 3D image fusion technique on the amount of administered iodinated contrast during endovascular common and/or external iliac artery interventions.Trial registrationNederlands Trial Register, NTR5008. Registered on 16 December 2014.

Preoperative Three-Dimensional Angiography May Reduce Ischemic Complications During Clipping of Ruptured Intracranial Aneurysms

Microsurgical clipping of aneurysms demands precise spatial understanding of aneurysm morphology and vascular geometry. We analyzed the impact of preoperative three-dimensional (3D) angiographic imaging on clinical and angiographic outcome after clipping of ruptured intracranial aneurysms. This is a retrospective analysis of consecutive patients who underwent microsurgical clipping during the acute phase of subarachnoid hemorrhage between 2010 and 2017. Surgical planning was made based on two-dimensional (2D) or 3D angiographic images. We retrospectively compared complication rates, morbidity, and angiographic outcome between these 2 groups. A total of 157 patients (mean age: 54.8 ± 13.1 years) were included in the study. Preoperative 3D angiographic imaging was available for 117 cases. The rate of procedure-related ischemia was significantly lower in the 3D group (16.2%) than in the 2D group (35.0%; P= 0.013). In the multivariate analysis, 2D imaging alone remained as independent factor for subsequent brain ischemia (odds ratio: 2.8, 95% confidence interval 1.2-6.6; P= 0.018). Favorable outcome (modified Rankin scale ≤2) was more often attained in the 3D group (70.0%) than in the 2D group (41.9%; P= 0.002). The rate of complete aneurysm occlusion was not significantly different between the 2 groups (P= 0.967). In our study, accurate operation planning using 3D angiography was associated with a lower ischemic complication rate after clipping of ruptured intracranial aneurysms, which may potentially influence clinical outcome.

23. Development of a software based on an anthropomorphic image atlas for image quality optimization in 3D angiography mode dynamic collimation system improving target conformity of spot scanning proton therapy: Comparison of dose calculations for two nozzles

Introduction In order to improve patient dose management [1] , a software was developed to enable the visualization of the effect of 3D angiography (3DA) protocol optimization on Image Quality (IQ) and radiation dose in interventional radiology. Methods For the four most representative anatomic areas of our clinical practice (liver, pelvis, lung, spleen), five reference protocols were set-up in our interventional radiology system (Innova IGS 540, GE Healthcare, Buc, France) with different IQ/dose preferences from low dose to high Image Quality (IQ). These preferences were defined by adjusting the Automatic Dose Rate and Image Quality (ADRIQ) strategy, the detail level and the rotation speed for 3DA sequences. For these 20 protocols, 3D angiography images were acquired on an anthropomorphic phantom (PBU-60, Kyoto Kagaku). All acquired images were qualitatively validated by a senior radiologist. These images were implemented in a home-made software (ProtoEnhanceIR) in order to optimize protocols by displaying the anthropomorphic images and associated Peak Skin Dose (PSD). The radiologist has the ability to select the most suitable protocols in regard with his own clinical practice. Then, the operator has the possibility to import selected protocols in the system. The PSD delivered to the anthropomorphic phantom by our 3DA clinical routine protocol (PSDRoutine) was compared to the PSD for the 3DA optimized protocol chosen by the senior radiologist in ProtoEnhanceIR (PSDProtoEnhanceIR). Results Compared to our 3DA clinical routine protocol, the chosen 3DA optimized protocol proposed by ProtoEnhanceIR allowed an average dose reduction of 69% while keeping clinical IQ (for lung, liver, pelvis and spleen PSDProtoEnhanceIR was 0.98 ± 0.09; 2.95 ± 0.43; 3.07 ± 0.27; 3.11 ± 0.34 mGy while PSDRoutine was 2.79 ± 0.12; 10.02 ± 0.89; 10.94 ± 1.31; 11.20 ± 0.58 mGy respectively). Conclusions The proposed software allows improvement of the IQ/dose balance of IR protocols according to radiologists’ preferences. From our clinical experience, ProtoEnhanceIR offers significant dose reduction opportunities while maintaining validated clinical IQ.

Computer-Assisted Adjuncts for Aneurysmal Morphologic Assessment: Toward More Precise and Accurate Approaches.

Neurosurgeons currently base most of their treatment decisions for intracranial aneurysms (IAs) on morphological measurements made manually from 2D angiographic images. These measurements tend to be inaccurate because 2D measurements cannot capture the complex geometry of IAs and because manual measurements are variable depending on the clinician's experience and opinion. Incorrect morphological measurements may lead to inappropriate treatment strategies. In order to improve the accuracy and consistency of morphological analysis of IAs, we have developed an image-based computational tool, AView. In this study, we quantified the accuracy of computer-assisted adjuncts of AView for aneurysmal morphologic assessment by performing measurement on spheres of known size and anatomical IA models. AView has an average morphological error of 0.56% in size and 2.1% in volume measurement. We also investigate the clinical utility of this tool on a retrospective clinical dataset and compare size and neck diameter measurement between 2D manual and 3D computer-assisted measurement. The average error was 22% and 30% in the manual measurement of size and aneurysm neck diameter, respectively. Inaccuracies due to manual measurements could therefore lead to wrong treatment decisions in 44% and inappropriate treatment strategies in 33% of the IAs. Furthermore, computer-assisted analysis of IAs improves the consistency in measurement among clinicians by 62% in size and 82% in neck diameter measurement. We conclude that AView dramatically improves accuracy for morphological analysis. These results illustrate the necessity of a computer-assisted approach for the morphological analysis of IAs.

WHICH MORPHOLOGIC AND HEMODYNAMIC CHARACTERISTICS PREDICT INTRACRANIAL FUSIFORM ANEURYSMS RUPTURE? A PATIENT-SPECIFIC COMPUTATIONAL FLUID DYNAMICS STUDY

To identify hemodynamic and morphological parameters leading to increased risk of intracranial fusiform aneurysms (IFA) rupture using computational fluid dynamics (CFDs). A total of 24 patient-specific fusiform aneurysms models on vertebral artery were reconstructed from 3D angiography images. 11 ruptured cases and 13 unruptured cases were included. Morphologic parameters were measured and CFD parameters were calculated using CFD simulation. The length of the aneurysm is significantly shorter in ruptured group than in unruptured group. The ratio of the width to the length of an aneurysm (WLR) and the ratio of the cross-section area to the length of an aneurysm (ALR) to the averaged cross sectional areas of the inlet and outlet of the parent artery (ALaR) were significantly higher in ruptured group compared with unruptured group. Wall shear stress (WSS) of the aneurysm was normalized to the WSS of the parent artery. Hemodynamically, only low WSS was associated with higher risk of rupture. Ruptured IFAs are shorter, have bigger WLR, ALaR, and lower WSS, compared with unruptured IFAs.

SU‐F‐I‐74: Dose Evaluation Based On Monte Carlo Simulation of Three‐Dimensional Rotational Angiography During Hepatic Transarterial Chemoembolization Procedures

Purpose:This study was aimed to investigate the dose with patient performing three‐dimensional (3D) angiography imaging during hepatic transarterial chemoembolization (TACE) procedures.Methods:Organ doses and effective doses calculations were retrospectively performed in 88 patients (61 males and 27 females with averaged age of 65.4±12.6 years old) referred for hepatic TACE on a digital flat‐panel angiography system (Bransist safire; Shimadzu) using software (PCXMC; Helsinki, Finland) based on Monte Carlo technique. Patient information (weight and height) and projection data were also used as parameters for dose calculations. Doses were evaluated of the 26 organs in 43 projections at 5° intervals from RAO 120° to LAO 95°. 3D rotational angiography images were acquired three times (before and after contrast, as well as after chemoembolization) using the same exposure techniques (100 kV, 360 mA and 5 ms pulse width) for each patient. Effective doses and dose conversion factors (CFs) were also calculated from the Monte Carlo data.Results:Upper abdominal organs, especially for the dorsal organs, showed the higher dose. Kidney received the highest dose (45.67 mGy) during the whole 3D procedure. Averaged DAP for 88 patients was 394.67±10.85 dGycm2. Averaged effective dose during the 3D procedure were 11.33 mSv. Significant inverse linear relationship was found between effective dose and patient weight (R2 =0.90). Averaged DAP‐to‐effective dose CF were 0.027 mSvdGy−1cm−2 in our study and tend to be decreased as patient weight increased (R2=0.92).Conclusion:Effective dose for the three acquisitions in the 3D rotational angiography of TACE is comparable to the effective dose for one series in the abdominal CT. By utilizing the conversion factors, the DAPs may be useful for estimating the effective dose during 3D abdominal angiographic imaging in the future.

Effects of Non-Newtonian Viscosity on the Hemodynamics of Cerebral Aneurysms

The purpose of this study is to present a comparative study between Newtonian and non-Newtonian blood viscosity models for simulating the hemodynamic wall shear stress (WSS) of cerebral aneurysms. The non-Newtonian blood viscosity was modeled using the Carreau-Yasuda nonlinear model. Two realistic cerebral aneurysm models, derived from 3D angiography imaging, were studied and simulated via computational fluid dynamics solver based on finite volume method, with a pulsating sinusoidal waveform boundary conditions. The maximum wall shear stresses were found at the aneurysm’s neck and apex, the inlet arteriole recorded an average wall shear stress and as for the blebs and tips the wall shear stress values were remarkably low. The comparison indicated that non-Newtonian blood viscosity model predicted a lower range of WSS than of the Newtonian model, which provides more accuracy for simulating aneurysm hemodynamics.

Analysis of superiorly projecting anterior communicating artery aneurysms: anatomy, techniques, and outcome. A proposed classification system.

Superiorly projecting (SP) anterior communicating artery (AComA) aneurysms are typically described as a homogenous group. Clinically and microsurgically, these aneurysms vary in multiple important characteristics. We propose a microsurgical classification system for these complex aneurysms and review its implications regarding presentation, microsurgical techniques, and outcome. This retrospective analysis reviews patients undergoing clipping of SP AComA aneurysms (2005-2013). The classification system is based on the virtual plane created by the A2 segments and its relationship to the aneurysm. Aneurysm type was assessed by intraoperative images and videos. Type 1 is defined by bisection of the dome by the virtual plane. Type 2 is defined by dome projection posterior to this plane. Sagittal rotation of the plane defines type 3. We analyzed clinical presentation, morphology, angiographic characteristics, operative technique, and outcome relative to the classification types. There were 44 SP AComA aneurysms. 3D angiographic images predicted classification type in 83%. Type 1 presented more often with SAH (95.5%, p = 0.0046). There was no statistically significant difference between the types regarding patient demographics or aneurysm characteristics. In type 2, fenestrated clips were used frequently (87.5% p= 0.0016), and there was higher rate of intraoperative rupture (37.5%). Although there was no statistically significant difference between the types in respect to HH grade upon presentation, patients with type 2 aneurysms experienced higher rates of poor GOS (50%). The proposed classification system for SP AComA aneurysms has implications regarding surgical planning, micro-dissection, clipping, and outcome. Type 2 aneurysms carry significant surgical risk.

Evaluation of High-quality Hepatic CT Angiography with Iterative Model Reconstruction

Objectives: To evaluate the quality of three-dimensional (3D) CT angiography images of the liver using iterative model reconstruction (IMR). Materials and Methods: Twenty-four patients with suspected disease of the pancreatobiliary system who had undergone CT reconstruction with filtered back projection (FBP) (Protocol A), iDose (hybrid IR) (Protocol B), and IMR (Protocol C) were evaluated. Contrast-to-noise ratios (CNR) relative to the liver, aorta, and portal vein were measured and recorded. The quality of 3D images under the same CT-threshold was graded on a scale of 1 (poor) to 5 (excellent). Results: The CNR of the artery and portal vein was highest when using protocol C. Mean value (±standard deviation) of the artery-to-liver CNRs for each protocol was as follows: A (6.95 ± 1.53), B (12.05 ± 2.38), and C (33.12 ± 7.93). Mean value (±standard deviation) of the portal vein-to-liver CNRs for each protocol was as follows: A (2.81 ± 0.62), B (5.17 ± 1.40), and C (10.27 ± 3.99). The quality of 3D images significantly differed between the three methods, with that of Protocol C being the highest. Conclusions: Compared to FBP and hybrid IR, abdominal CT scans via IMR produced higher-quality 3D angiography images of the liver at the same radiation dose and with significant improvements in CNR.

Laparoscopic intraoperative navigation surgery for gastric cancer using real-time rendered 3D CT images.

Recent advances in laparoscopic surgical technology have made it possible to perform advanced high-level surgery, such as lymph node dissection for malignancy. Grasping the anatomy during such procedures is important for a safe operation. We have developed a new image information system that provides three-dimensional (3D) reconstructed CT images synchronized with the motion of the laparoscope. This study assesses this new navigation system. Enhanced CT using a custom-made software program can provide 3D angiography images reconstructed as a laparoscopic view. A motion sensor mounted on the laparoscope can detect the direction angle of the laparoscope. The real-time rendered 3D CT images are synchronized with the laparoscopic video images according to the motion of the scope. These 3D CT images are projected on another monitor close to the laparoscopic video monitor. Lymph node dissection can be performed with the help of the real-time navigation system that provides a detailed 3D view of the vasculature. Ten laparoscopic gastrectomies were performed using this navigation system. Real-time intraoperative navigation of the vasculature was available, allowing for an excellent surgical outcome. No complications occurred in this series. Our intraoperative navigation system allows for safe laparoscopic gastric lymph node dissection.