Real-time passive cavitation mapping and B-mode fusion imaging via hybrid adaptive beamformer with modified diagnostic ultrasound platform.

The implementation of real-time, convenient and high-resolution passive cavitation imaging (PCM) is crucial for ensuring the safety and effectiveness of ultrasound applications related to cavitation effects. However, the current B-mode ultrasound imaging system cannot achieve these functions. By developing a hybrid adaptive beamforming algorithm, the current work presented a real-time PCM and B-mode fusion imaging technique, using a modified diagnostic ultrasound platform enabling time-division multiplexing external triggering function. The proposed hybrid adaptive beamformer combined the advantages of delay-multiply-and-sum (DMAS) and minimum variance (MV) methods to effectively suppress the side lobe and tail-like artifacts, improving the resolution of PCM images. A high-pass filter was applied to selectively detect cavitation-specific signals while removing the interference from the tissue scatters. The system enabled synchronous visualization of tissue structure and cavitation activity under ultrasound exposure. Both numerical and experimental studies demonstrated that, compared with DAS, MV-DAS and DMAS methods, the proposed MV-DMAS algorithm performed better in both axial and lateral resolutions. This work represented a significant advancement in achieving high-quality real-time B-mode and PCM fusion imaging utilizing commercial medical ultrasound system, providing a powerful tool for synchronous monitoring and manipulating cavitation activity, which would enhance the safety and efficacy of cavitation-based applications.

G2NPAN: GAN-guided nuance perceptual attention network for multimodal medical fusion image quality assessment.

Multimodal medical fusion images (MMFI) are formed by fusing medical images of two or more modalities with the aim of displaying as much valuable information as possible in a single image. However, due to the different strategies of various fusion algorithms, the quality of the generated fused images is uneven. Thus, an effective blind image quality assessment (BIQA) method is urgently required. The challenge of MMFI quality assessment is to enable the network to perceive the nuances between fused images of different qualities, and the key point for the success of BIQA is the availability of valid reference information. To this end, this work proposes a generative adversarial network (GAN) -guided nuance perceptual attention network (G2NPAN) to implement BIQA for MMFI. Specifically, we achieve the blind evaluation style via the design of a GAN and develop a Unique Feature Warehouse module to learn the effective features of fused images from the pixel level. The redesigned loss function guides the network to perceive the image quality. In the end, the class activation mapping supervised quality assessment network is employed to obtain the MMFI quality score. Extensive experiments and validation have been conducted in a database of medical fusion images, and the proposed method is superior to the state-of-the-art BIQA method.

Three-dimensional ultrasound fusion imaging in precise needle placement for thermal ablation of hepatocellular carcinoma.

PURPOSE: To investigate the value of three-dimensional ultrasound fusion imaging (3DUS FI) technique for guiding needle placement in hepatocellular carcinoma (HCC) thermal ablation. METHODS: A total of 57 patients with 60 HCCs with 3DUS FI-guided thermal ablation were retrospectively included in the study. 3DUS volume data of liver were acquired preoperatively by freehand scanning with the tumor and predetermined 5 mm ablative margin automatically segmented. Plan of needle placement was made through a predetermined simulated ablation zone to ensure a 5 mm ablative margin with the coverage rate toward tumor and ablative margin. With real-time ultrasound and 3DUS fusion imaging, ablation needles were placed according to the plan. After ablation, the ablative margin was immediately evaluated by contrast-enhanced ultrasound and 3DUS fusion imaging. The rate of adequate ablative margin, complete response (CR), local tumor progression (LTP), disease-free survival (DFS), and overall survival (OS) was evaluated. RESULTS: According to postoperative contrast-enhanced CT or MR imaging, the complete response rate was 100% (60/60), and 83% of tumors (30/36) achieved adequate ablative margin (>5 mm) three-dimensionally. During the follow-up period of 6.0-42.6 months, LTP occurred in 5 lesions, with 1- and 2-year LTP rates being 7.0% and 9.4%. The 1- and 2-year DFS rates were 76.1% and 65.6%, and 1- and 2-year OS rates were 98.1% and 94.0%. No major complications or ablation-related deaths were observed in any patients. CONCLUSIONS: Three-dimensional ultrasound fusion imaging technique may improve the needle placement of thermal ablation for HCC and reduce the rate of LTP.

Utilization of three-dimensional fusion images with high-resolution computed tomography angiography for preoperative evaluation of microvascular decompression: patient series.

BACKGROUND: High-resolution computed tomography (CT), outfitted with a 0.25-mm detector, has superior capability for identifying microscopic anatomical structures compared to conventional CT. This study describes the use of high-resolution computed tomography angiography (CTA) for preoperative microvascular decompression (MVD) assessment and explores the potential effectiveness of three-dimensional (3D) image fusion with magnetic resonance imaging (MRI) by comparing it with traditional imaging methods. OBSERVATIONS: Four patients who had undergone preoperative high-resolution CTA and MRI for MVD at Osaka University Hospital between December 2020 and March 2022 were included in this study. The 3D-reconstructed images and intraoperative findings were compared. One patient underwent conventional CTA, thus allowing for a comparison between high-resolution and conventional CTA in terms of radiation exposure and vascular delineation. Preoperative simulations reflected the intraoperative findings for all cases; small vessel compression of the nerve was identified preoperatively in two cases. LESSONS: Compared with conventional CTA, high-resolution CTA showed superior vascular delineation with no significant change in radiation exposure. The use of high-resolution CTA with reconstructed 3D fusion images can help to simulate prior MVD. Knowing the location of the nerves and blood vessels can perioperatively guide neurosurgeons.

The usefulness of three-dimensional fusion imaging of spinal arteriovenous malformation by a workstation connected to angiography systems.

Digital subtraction angiography (DSA) is the most useful technique for diagnosing spinal arteriovenous malformations (AVM). In recent years, with the improvement of imaging capabilities, the usefulness of three-dimensional (3D) imaging by fusing various modalities has been recognized. The use of 3D fusion imaging with a workstation connected to an angiography system has been reported in many cases of intracranial disease, but less frequently for spinal AVM. In this article, we describe two illustrative cases of spinal AVM in which 3D fusion imaging was useful for treatment. Although 3D fusion images using the system have the disadvantage that only a maximum of two images can be fused, it provides spinal surgeons with useful information for preoperative evaluation in a small amount of time.

Efficacy of Utilizing Both 3-Dimensional Multimodal Fusion Image and Intra-Arterial Indocyanine Green Videoangiography in Cerebral Arteriovenous Malformation Surgery.

OBJECTIVE: An understanding of the complex morphology of an arteriovenous malformation (AVM) is important for successful resection. We have previously reported the utility of intra-arterial indocyanine green (ICG) videoangiography for this purpose, but that method cannot detect the angioarchitecture covered by brain tissue. 3-dimensional (3D) multimodal fusion imaging is reportedly useful for this same purpose, but cannot always visualize the exact angioarchitecture due to poor source images and processing techniques. This study examined the results of utilizing both techniques in patients with AVMs. METHODS: Both techniques were applied in 12 patients with AVMs. Both images were compared with surgical views and evaluated by surgeons. RESULTS: Although evaluations for identifying superficial feeders by ICG videoangiography were high in all cases, the more complicated the AVM, the lower the evaluation by 3D multimodal fusion imaging. Conversely, evaluation of the estimated range of the nidus was high in all cases by 3D multimodal fusion imaging, but low in all but one case by ICG videoangiography. Nidus flow reduction was recognized by Flow 800 analysis obtained after ICG videoangiography. CONCLUSIONS: These results showed that utilizing both techniques together was more useful than each modality alone in AVM surgery. This was particularly effective in identifying superficial feeders and estimating the range of the nidus. This technique is expected to offer an optimal tool for AVM surgery.

Clearance of the liver remnant predicts short-term outcome in patients undergoing resection of hepatocellular carcinoma.

BACKGROUND: Estimation of the functional reserve of the remnant liver is important to reduce morbidity and mortality. AIM: To estimate the functional reserve of the remnant liver in patients with hepatocellular carcinoma (HCC). METHODS: We reviewed the medical records of 199 patients who underwent resection of HCC. Hepatic clearance of the remnant liver was calculated using fusion images of 99mTc-labelled galactosyl-human serum albumin liver scintigraphy and computed tomography. Posthepatectomy liver failure (PHLF) was classified according to the International Study Group of Liver Surgery. Complications was classified according to Clavien-Dindo classification. We analyzed by the risk factors for PHLF, morbidity and mortality with multivariate analysis. RESULTS: Twenty-seven (30%) patients had major complications and 23 (12%) developed PHLF. The incidence of major complications increased with increasing albumin-bilirubin (ALBI) grade. The area under the curve values for hepatic clearance of the remnant liver, liver to heart-plus-liver radioactivity at 15 min (LHL15), and ALBI score predicting PHLF were 0.868, 0.629, and 0.655, respectively. The area under the curve for hepatic clearance of the remnant liver, LHL15, and ALBI score predicting major complications were 0.758, 0.594, and 0.647, respectively. The risk factors for PHLF and major complications were hepatic clearance of the remnant liver and intraoperative bleeding. CONCLUSION: The measurement of hepatic clearance may predict PHLF and major complications for patients undergoing resection of HCC.

[Carotid artery stenting using cerebral angiography 3D fusion imaging without contrast agent: a case report].

A 79-year-old-man with a clinical history of type 2 diabetes and hypertension was admitted to our hospital for recurrent right hemiparesis. He was referred to our department with left internal carotid artery stenosis. Cerebral angiography with a slight contrast agent revealed NASCET 86% stenosis at the left internal carotid bifurcation. Although no neurological deficit was observed, he had a renal dysfunction with an estimated glomerular filtration rate of 32.2 ml/min/1.73 m2. We used a 3D fusion image obtained from the initial angiography with B-mode and intravascular ultrasound to avoid aggravating renal function instead of using a contrast medium. Following the procedure, favorable expansion of the stenotic region was achieved, and no evidence of recurrence was seen during the follow-up period. 3D fusion imaging is a valuable and safe method for endovascular treatment of carotid artery stenosis for patients with renal dysfunction.

Usefulness of the Multimodal Fusion Image for Visualization of Deep Sylvian Veins.

The preoperative assessment of cerebral veins is important to avoid unexpected cerebral venous infarction in the neurosurgical setting. However, information is particularly limited regarding deep Sylvian veins, which occasionally disturb surgical procedures for cerebral anterior circulation aneurysms. The predictability of detecting deep Sylvian veins and their tributaries using a modern multimodal fusion image was aimed to be evaluated. Moreover, 51 patients who underwent microsurgery for unruptured cerebral aneurysms with Sylvian fissure dissection were retrospectively reviewed. The visualization of the four components of the deep Sylvian veins in conventional computed tomography (CT) venography and multimodal fusion images was evaluated. To compare the detection accuracy among these radiological images, the sensitivity and specificity for the detection of each of the four venous structures were calculated in comparison with those of intraoperative inspections. The kappa coefficients were also measured and the inter-rater agreement for each venous structure in each radiological image was examined. In all veins, the multimodal fusion image exhibited a high detection rate without statistical difference from intraoperative inspections (P = 1.0). However, CT venography exhibited a low detection rate with a significant difference from intraoperative inspections in the common vertical trunk (P = 0.006) and attached vein (P = 0.008). The kappa coefficients of the fusion image ranged from 0.73 to 0.91 and were superior to those of CT venography for all venous structures. This is the first report to indicate the usefulness of a multimodal fusion image in evaluating deep Sylvian veins, especially for the detection of nontypical, relatively small veins with large individual variability.

Feasibility of Preoperative Magnetic Resonance Angiography/Black-Blood Magnetic Resonance Imaging/Computed Tomography Fusion Imaging Without Contrast Agent for Carotid Endarterectomy.

BACKGROUND: Preoperative identification of the carotid bifurcation (CB) location and plaque and stenosis distal end of the cervical internal carotid artery in relation to bony structures is essential for carotid endarterectomy (CEA). However, for patients with contrast contraindications, cervical 3-dimensional computed tomography angiography (3D-CTA) is unavailable. In this study, we created fusion images of magnetic resonance angiography (MRA), black-blood (BB) magnetic resonance imaging (MRI), and CT to determine if these noncontrast agent images are superior to 3D-CTA for preoperative CEA planning. METHODS: The fusion images showed vascular structures obtained by MRA, plaque observed by BB-MRI, and bone structures shown by CT. Spatial localization accuracy was verified by directly overlaying contrast-enhanced 3D-CTA images on the fusion images. We validated this technique in 50 patients with unilateral ICA stenosis, 28 of whom underwent CEA. The 2D-distance CB MRA-CTA (the 2D distance difference between CB MRA and CB CTA perpendicular to the long axis of the carotid artery) was measured. We also compared the findings of the fusion image regarding the CB location and plaque distal end with the operative findings. RESULTS: The median 2D distance CB MRA-CTA was 1 mm. CB MRA was located distal and proximal to CB CTA in 21and 29 patients, respectively. The CB location and fusion-image plaque were consistent with the intraoperative findings in all CEA patients. CONCLUSIONS: Fusion images created from MRA, BB-MRI, and noncontrast CT were feasible as an alternative to 3D-CTA for patients with contrast contraindications.

How to Precisely Open the Internal Auditory Canal for Resection of Vestibular Schwannoma via the Retrosigmoid Approach.

Objective: The aim of this study was to investigate how to precisely expose the intrameatal portion of vestibular schwannomas (VSs) without damaging the labyrinth. Methods: This was a retrospective study of patients who had undergone retrosigmoid resection of a VS in our institution from April 2018 to December 2021. The patients were divided into microsurgery (MS) and navigation endoscopic-assisted (combined surgery, CS) groups and the effects of image guidance and endoscopy evaluated. The tumors in the CS group were then divided into medial and lateral types by fusion imaging and the differences between the two types analyzed. Results: Data of 84 patients were analyzed. Residual tumor was detected by postoperative MRI at the fundus of the internal auditory canal in 5 of the 31 patients in the MS group and 1 of the 53 in the CS group. The labyrinth was damaged in four patients in the MS group but was not damaged in any of the CS group patients. The CS group included 29 lateral type and 24 medial type schwannomas. Endoscopic-assisted resection of residual tumor in the IAC was performed significantly more often on medial than on lateral tumors. Conclusion: Navigation and endoscopy are useful in assisting the exposure of the intrameatal portion of VSs. Preoperative MRI/CT fusion imaging is helpful in preoperative evaluation and surgical planning in patients undergoing VS surgery. Tumors of the medial type require endoscopic assistance for resection.

Experience in utilizing a novel 3D digital model with CT and MRI fusion data in sarcoma evaluation and surgical planning.

OBJECTIVE: To assess sarcoma margins with more accuracy and aid surgical planning, we constructed three-dimensional (3D) digital models with computed tomography(CT) and magnetic resonance imaging (MRI) image fusion data and validated the preciseness of the models by comparing them with 3D models constructed with CT only data. MATERIALS AND METHODS: We retrospectively reviewed a consecutive set of patients treated in our center who were preoperatively evaluated with the fusion image model. Models based on fusion images or CT-only data were constructed. Volumes of both tumors were calculated and the tumors were overlapped to see the location of differences between the two models. RESULTS: A consecutive 12 cases (4 male vs. 8 female) were included in this study. Most of the tumors were located in the pelvic bone or spine. The volume of the two tumor models was different and the differences were mainly in the peripheral region of the tumor. CONCLUSION: CT and MRI fusion image 3D models are more accurate than models with CT-only data and can be very helpful in preoperative planning of sarcoma patients.

Computational Fractional Flow Reserve From Coronary Computed Tomography Angiography-Optical Coherence Tomography Fusion Images in Assessing Functionally Significant Coronary Stenosis.

Background: Coronary computed tomography angiography (CTA) and optical coherence tomography (OCT) provide additional functional information beyond the anatomy by applying computational fluid dynamics (CFD). This study sought to evaluate a novel approach for estimating computational fractional flow reserve (FFR) from coronary CTA-OCT fusion images. Methods: Among patients who underwent coronary CTA, 148 patients who underwent both pressure wire-based FFR measurement and OCT during angiography to evaluate intermediate stenosis in the left anterior descending artery were included from the prospective registry. Coronary CTA-OCT fusion images were created, and CFD was applied to estimate computational FFR. Based on pressure wire-based FFR as a reference, the diagnostic performance of Fusion-FFR was compared with that of CT-FFR and OCT-FFR. Results: Fusion-FFR was strongly correlated with FFR (r = 0.836, P < 0.001). Correlation between FFR and Fusion-FFR was stronger than that between FFR and CT-FFR (r = 0.682, P < 0.001; z statistic, 5.42, P < 0.001) and between FFR and OCT-FFR (r = 0.705, P < 0.001; z statistic, 4.38, P < 0.001). Area under the receiver operating characteristics curve to assess functionally significant stenosis was higher for Fusion-FFR than for CT-FFR (0.90 vs. 0.83, P = 0.024) and OCT-FFR (0.90 vs. 0.83, P = 0.043). Fusion-FFR exhibited 84.5% accuracy, 84.6% sensitivity, 84.3% specificity, 80.9% positive predictive value, and 87.5% negative predictive value. Especially accuracy, specificity, and positive predictive value were superior for Fusion-FFR than for CT-FFR (73.0%, P = 0.007; 61.4%, P < 0.001; 64.0%, P < 0.001) and OCT-FFR (75.7%, P = 0.021; 73.5%, P = 0.020; 69.9%, P = 0.012). Conclusion: CFD-based computational FFR from coronary CTA-OCT fusion images provided more accurate functional information than coronary CTA or OCT alone. Clinical Trial Registration: [www.ClinicalTrials.gov], identifier [NCT03298282].

Ingenuity using 3D-MRI fusion image in evaluation before and after microvascular decompression for hemifacial spasm.

Background: Hemifacial spasm (HFS) is most often caused by blood vessels touching a facial nerve. In particular, responsible vessels compress the root exit zone (REZ) of the facial nerve. Although we recognize these causes of HFS, it is difficult to evaluate the findings of precise lesion in radiological imaging when vessels compress REZ. Hence, we tried to obtain precise images of pre- and postoperative neuroradiological findings of HFS by creating a fusion image of MR angiography and the REZ of facial nerve extracted by magnetic resonance imaging (MRI) diffusion tensor image (DTI). Case Description: A 52-year-old woman had a 2-year history of HFS on the left side of her face. It was confirmed that the left vertebral artery and anterior inferior cerebellar artery were presented near the facial nerve on MRI. REZ of the facial nerve was visualized using DTI and fusion image was created with vascular components, making it possible to recognize the relationship between compression vessels and REZ of the facial nerve in detail. She underwent microvascular decompression and her HFS completely disappeared. We confirmed that the REZ of the facial nerve was decompressed by MRI imaging, in the same way as before surgery. Conclusion: We describe that the REZ of facial nerve and compressive vessels was delineated in detail on MRI and this technique is useful for pre- and postoperative evaluation of HFS.

Usefulness of 3D CT/MRI Fusion Imaging for the Evaluation of Lumbar Disc Herniation and Kambin's Triangle.

Study design: Prospective study. Objective: The aim of this study is to visualize the morphology of a lumbar herniated disc and Kambin's triangle in three dimensions (3D) based on preoperative CT/MRI fusion images. Methods: CT/MRI fusion images of 23 patients (10 males and 13 females; mean age 58.2 years) were used to evaluate Kambin's triangle, which is created between the superior articular process (SAP), exiting nerve root (ENR), inferiorly by the superior endplate of the lower lumbar vertebra and dural canal medially at 60 degree and 45 degree endoscopic approach angles. The percentage of the safe usage of transforaminal endoscopic approach was evaluated to utilize a 5 mm dilater without partial facet resection in the fusion image. The 3D lumbar nerve root sleeve angulation (3DNRA), which is the angle between the axis of the thecal sac and the nerve root sleeve, was calculated. The herniated discs were also visualized in the CT/MRI fusion image. Results: The 3DNRA became smaller from L2 to S1. The L2 3DNRA was statistically larger than those of the other root, and the S1 3DNRA was significantly smaller than the others (p < 0.05). (L2, 41.0°; L3, 35.6°; L4, 36.4°; L5, 33.9°; and S1, 23.2°). The SAP-ENR distance at 60° was greatest at L4/5 (5.9 mm). Possible needle passages at 60° to each disc level were 89.1% at L2/3, 87.0% at L3/4 and 84.8% at L4/5. However, the safe 5 mm dilater passage at 60° without bony resection to each disc level were 8.7% at L2/3, 28.3% at L3/4 and 37.0% at L4/5. The 60° corridor at L2/3 was the narrowest (p < 0.01). All herniated discs were visualized in the fusion image and the root compression site was clearly demonstrated especially with foraminal/extraforaminal herniations. Conclusion: The 3D lumbar CT/MRI fusion image enabled a combined nerve-bony assessment of Kambin's triangle and herniated disc. A fully endoscopic 5 mm dilater may retract the exiting nerve root in more than 60% of total cases. This new imaging technique could prove to be very useful for the safety of endoscopic lumbar disc surgery.

Percutaneous transhepatic coil and cover technique with small system for the extrahepatic portal vein hemorrhage after pancreaticoduodenectomy.

Post-pancreaticoduodenectomy hemorrhage is a life-threatening complication that usually occurs in skeletonized arteries. Venous hemorrhage is a rarer complication, and surgical management is often challenging. We herein report the case of an 80-year-old man who suffered from prolonged pancreatic fistula and long-term drainage tube placement, which could cause late post-pancreaticoduodenectomy hemorrhage from the confluence of the splenic and extrahepatic portal veins. An intrahepatic posterior portal venous branch was percutaneously punctured, and the splenic vein was embolized using coils and a vascular plug. A balloon-expandable covered stent was also placed from the superior mesenteric vein to the main portal vein to cover the confluence, which required a system as small as 8-F. Portal venography revealed good patency without extravasation. Thereafter, antithrombotic and antibacterial treatments were successfully administered without any additional interventions. He remained well without any evidence of thrombosis or indolent infection 19 months after endovascular treatment. The endovascular coil and cover technique with prolonged adjuvant therapy is a feasible alternative for managing such critical situations.

The Utility of Augmented Reality in Spinal Decompression Surgery Using CT/MRI Fusion Image.

In spine surgery, instrumentation surgery using augmented reality (AR) and navigation systems have become widespread, while decompression surgery using those applications is not so common. However, we sometimes encounter intraoperative problems such as excessive blood loss or bony resection in decompression surgery. Therefore, a practical navigation system is needed for safer spinal decompression surgery. Furthermore, the cost of AR and navigation systems has been expensive. In this study, we report the utility of applying the AR system of the head-mounted display (HMD) at a lower cost to identify the osteotomy area of laminectomy for spinal decompression surgery. 3D CT/MRI fusion images are created preoperatively to generate 3D data consisting of the nerve elements, a dural tube and nerve roots, and the bony elements of the spine. Then, we made the 3D data of the bone after decompression by 3D editing free software. Uploading the created 3D data of both 3D CT/MRI fusion and preoperative planned laminectomy images to the AR software in the HMD, we could confirm the proper decompression area with the 3D images projected through the HMD. This system was useful for cervical and lumbar decompression for confirming the proper decompression area preoperatively. We could perform decompression surgery just designed with this system. This system is a preoperative planning system that allows 3D HMD visualization to keep track of surgical orientation. It does not allow preoperative verification so far. However, this system has various possible applications and is considered a promising system for the future.

Surgical Simulation with Three-Dimensional Fusion Images in Patients with Arteriovenous Malformation.

In arteriovenous malformation (AVM) surgery, vessel structures should be well evaluated with angiography. However, with conventional angiography, it is sometimes difficult to distinguish each feeder and its feeding territory in the nidus. In this study, we used two software systems to create three-dimensional (3D) fusion images using multiple imaging modalities and evaluated their clinical use. In the AVM patient, data were obtained from 3D rotational angiography, rotational venography, computed tomography (CT), and magnetic resonance imaging (MRI) and superimposed into 3D fusion images using imaging software (iPLAN and Avizo). Virtual surgical fields that were quite similar to the real ones were also created with these software programs. Compared with fusion images by iPLAN, those by Avizo have higher resolution and can demarcate not only each feeder but also its supplying territory in the nidus with different colors.In conclusion, 3D fusion images in AVM surgery are helpful for simulation, even though it takes time and requires special skill to create them.

Evaluation of the Efficacy and Toxicity of Radiotherapy for Type III-IV Portal Vein Tumor Thrombi.

BACKGROUND: Type Ⅲ and Ⅳ portal vein tumor thrombi (PVTT) cannot be removed through surgery, and no effective therapeutic procedure is available. Type Ⅲ/Ⅳ PVTT can be downstage to type I/II PVTT by using Radiotherapy, and can further be can be removed surgically. Thus, radiotherapy may be an effective treatment for type Ⅲ/Ⅳ PVTT. This study aims to evaluate the efficacy and toxicity of radiotherapy for type III-IV PVTT. METHODS: This prospective study was conducted from August 1, 2017, to September 30, 2019, for patients with type Ⅲ and Ⅳ PVTT. Patients received radiotherapy with a target dose of 50Gy/25f or 59.5Gy/17 f. Advanced radiological technique such as image fusion technique for CT image and MRI image were utilized to produce more precise lesion localization, and limit the dose to organs at risk in order to get a better downstage rate and less adverse complications. RESULTS: Nine (9) patients with type Ⅲ PVTT and 5 patients with type Ⅳ PVTT were included in this study. 12 patients received a radiotherapy dose of 50Gy/25f, 2 patients received 59.50Gy/17 f. After radiotherapy, 92.9% of patients with PVTT were successfully downstage to type II/I. In patients with primary hepatocellular carcinoma, 8 patients (accounting 88.9%) achieved down-stage. 5 patients with other types of tumors achieved downstage which accounts 100%. In addition, none of the 14 patients observed radiation hepatitis and radiation liver failure. And none of the patients developed gastrointestinal ulcers and thrombocytopenia. CONCLUSION: Radiotherapy is a suitable treatment measure for type Ⅲ and Ⅳ PVTT to get downstage and make the opportunity for surgery. Image fusion technology for precise lesion location such as CT-MRI image fusion, and strict dose limitation of organ at risk, contributed to the improvement of radiotherapy efficiency and the significant decrease in adverse complications.

Microcatheter Re-Shaping Using Fusion Image in Coil Embolization: A Technical Note.

Objective: We report the utility of microcatheter reshaping by referring to fusion images with 3D-DSA and microcatheter 3D images made using non-subtraction and non-contrast (non-SC) rotational images. Case Presentations: Case 1: The patient was a 74-year-old man who had an internal carotid-anterior choroidal artery bifurcation aneurysm with a tortuous proximal parent artery. The initial attempt to introduce the microcatheter into the aneurysm was unsuccessful. During this unsuccessful microcatheter introduction, we created fusion images with 3D-DSA and microcatheter 3D images by acquiring positional information of the microcatheter using the non-SC method. By reshaping the microcatheter with reference to the fusion images, the direction of the distal end of the microcatheter was reshaped to be in accordance with the long axis of the aneurysm, a shape more suitable for coiling. Case 2: The patient was a 47-year-old man who had an anterior communicating (A-com) artery aneurysm with two daughter sacs. We successfully placed two microcatheters in the direction of each sac to make more stable framing by referring to 3D fusion images after the first microcatheter was positioned. In both cases, microcatheter reshaping was necessary because of the vessel and aneurysm anatomy. We have used this technique successfully in 15 patients, for both ruptured and unruptured aneurysms. The average number of microcatheter reshaping was 1.3 times. Conclusion: This method provides effective microcatheter reshaping for coil embolization of aneurysms, particularly those with differences between the axis of the parent artery and the vertical axis of aneurysm, or with a tortuous proximal artery.