Successful coil embolization of post-hepatectomy arterioportal fistula that reduced ascites and improved liver function

A 71-year-old man had previously undergone S7 + S8 dorsal segmentectomy and S5 partial hepatectomy for hepatocellular carcinomas. Six months later, he experienced abdominal distention. Abdominal computed tomography (CT) showed massive ascites and a significant hepatic arterioportal shunt. The ascites was thought to be caused by portal hypertension due to a high-flow hepatic arterioportal fistula (HAPF). The fistula, located between the right hepatic artery A7 and the right portal vein, was embolized with microcoils under flow control using a balloon catheter. After embolization, the shunt blood flow disappeared and the hepatopetal venous flow was restored. His body weight and abdominal circumference decreased immediately, and his liver function on blood tests improved after the procedure. CT performed 11 days after embolization showed decreased ascites. A HAPF after hepatectomy is extremely rare. Balloon-assisted embolization using microcoils is a useful endovascular procedure for treating a high-flow HAPF.

Cerebral chronic hypoperfusion in mice causes premature aging of the cerebrovasculature

Chronic cerebral hypoperfusion (CCH) is the main characteristic of an aged brain showing cerebrovascular alterations. Our previous study that the morphological changes in the pial arteries accompany a decrease in the cerebral blood flow in aged mouse brains, and it raises the question of whether artificial CCH can induce the same changes in brain vessel morphology. Here, we examined the effect of CCH on cerebrovascular morphology. Using a microcoil-induced chronic cerebral hypoperfusion (MCH) model, we induced CCH for 8 and 12 weeks. The cerebrovasculature morphology was evaluated using three-dimensional vessel analysis and compared with that of aging mice. We found the morphological changes in brain vessels of MCH mice, indicating that the CCH can induce cerebrovascular alteration. However, the changes in brain vessel morphology in the MCH mice were different in detail from those in the aging mice. Aging mice showed an increase in vessel tortuosity and thinned string vessels; MCH mice mainly showed thinned string vessels. This suggests that CCH may be a cause of age-related cerebrovascular alterations.

CT-guided placement of microcoil end in the pleural cavity for video-assisted thoracic surgical resection of ground-glass opacity: a retrospective study

BACKGROUND

The aim of the study was to investigate and summarize the effectiveness and safety of CT-guided microcoil localization before video-assisted thoracic surgery (VATS) for the removal of ground-glass opacity (GGO).

METHODS

A total of 147 patients with GGO who were treated at our hospital between January 2019 and February 2021 were retrospectively analyzed. They were divided into two groups according to the final position at the end of the microcoil: intracavity (n = 78) and extracavity (n = 69), which were compared based on puncture complications and influence of the coil end position on VATS.

RESULTS

The proportions of supine and prone positions in the intracavity group were significantly higher than those in the extracavity group (82.1% vs. 66.7%, P < 0.05). The incidence of intrapulmonary hemorrhage, chest pain, and coil displacement in the intracavity group was significantly lower than that in the extracavity group (28.2% vs. 46.4%, 19.2% vs. 39.1%, 1.3% vs. 11.6%, P < 0.05, respectively); however, the incidence of pneumothorax was not significantly different (P > 0.05). The time of VATS and the rate of conversion to thoracotomy in the intracavity group were significantly lower than those in the extracavity group (103.4 ± 21.0 min vs. 112.2 ± 17.3 min, 0% vs. 5.8%, P < 0.05, respectively).

CONCLUSION

CT-guided placement of the microcoil is a practical, simple, and convenient localization method before VATS, with a high success rate and few complications. Furthermore, it is a better alternative method to place the end of the coil in the pleural cavity because of the lower complication rate, shorter VATS time, and lower rate of thoracotomy conversion.

3T high-resolution magnetic resonance imaging, conventional ultrasonography and ultrasound biomicroscopy of the normal canine eye

Background

Advances in MRI coil technology and increased availability of high-field MRI in veterinary medicine enable the acquisition of images of increasingly high spatial resolution while preserving signal-to-noise ratio.The purpose of the present study was to compare 3T high-resolution magnetic resonance imaging (HR-MRI) with ultrasound (US) and ultrasound biomicroscopy (UBM) in the normal canine eye, to assess its potential to depict normal ocular anatomy.

Results

HR-MRI was compared with US and UBM in 10 eyes from 10 healthy beagle dogs. Ocular structures (cornea, anterior chamber, iridocorneal angle, iris, lens, ciliary body, choroid, vitreous body, posterior wall of the eye, optic nerve and optic nerve sheath, extraocular muscles) were assessed subjectively and central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth (AQD), anteroposterior, mediolateral and dorsoventral lens diameter (APLD, MLLD, DVLD), anteroposterior diameter of the globe including and excluding the scleroretinal rim (APDSRR, APD), vitreous chamber depth (VCD) and optic nerve sheath diameter (ONSD) were measured in HR-MRI and in US. Optic nerve diameter (OND) was measured in HR-MRI. HR-MRI and UBM appearance of the anterior segment were subjectively compared. Detailed reference high-resolution MRI images of normal eyes of Beagle dogs are provided.

Conclusions

HR-MRI allowed assessment of all structures identified with US and UBM. The MRI examinations were performed under general anesthesia with the addition of a neuromuscular blocking agent, while US and UBM examinations were performed in conscious animals. Visibility of the entire ocular wall, the lens, the structures caudal to the ciliary body and the optic nerve and its sheath was superior with HR-MRI. HR-MRI allowed the distinction of retina, choroid and sclera, and the delineation of structures not previously identified in canine eyes with MRI, including Tenon’s capsule and the sub-Tenon’s space.Plane selection was more accurate with HR-MRI compared to US. In general, the range of measurements was narrower for MRI than for US. CCT, AQD, APLD, MLLD, APD, APDSRR and ONSD differed significantly between HR-MRI and US, respectively (p = 0.005-0.027).Micro-MRI may be useful for the assessment of ocular pathologies in the future.

The normalized limit of detection in NMR spectroscopy

We derive the normalized limit of detection for frequency space (nLOD_f) as a parameter to measure the sensitivity of an NMR spectroscopy setup. nLOD_f is independent of measurement settings such as bandwidth or number of measurement points, and allows to compare performances of different setups. We demonstrate the usefulness of the new nLOD_f by comparing the sensitivity of NMR setups from various publications, which all use microcoils. Finally, we want to propose a standard measurement and report format for the sensitivity of new NMR setups.

Modified microcoil for preoperative localization of solitary pulmonary nodules: a prospective, single-arm, multicenter clinical study

PURPOSE

To evaluate the efficacy and safety of placement of a modified microcoil for precise preoperative localization of solitary pulmonary nodules (SPNs) before video-assisted thoracoscopic surgery(VATS).

MATERIALS AND METHODS

This prospective single-arm multicenter study included patients who underwent computed tomography (CT)-guided modified microcoil insertion prior to SPN resection by VATS between January 2018 and June 2018. The patient demographics, nodule characteristics and histopathologic findings were recorded. The primary endpoints included efficacy and safety.

RESULTS

A total of 96 patients (41 males and 55 females; mean age: 59.3 ± 8.9 years) with 96 SPNs were eligible for enrolment in the study. The mean maximal transverse diameter of the nodules was 10.3 ± 5.2 mm (range: 8-20 mm). The mean time between CT-guided microcoil insertion and the start of the surgical procedure was 14.6 hours (range: 12-24 hours). The duration of the preoperative CT-guided microcoil localization procedure was 29 ± 9 minutes (range: 10-35 minutes), and the intraoperative fluoroscopy time was 0.7 ± 0.7 minutes (range: 0.5-3 minutes). The clinical success rate was 96.9%(93/96), and all nodules were successfully resected using VATS. One patient experienced asymptomatic pneumothorax, but there were no cases of pulmonary hemorrhage.

CONCLUSIONS

SPN localization with the modified microcoil is feasible and safe. The modified microcoil can facilitate the thoracoscopic resection of SPNs.

[Preoperative Pulmonary Nodule Localization Methods:A Comparison of Microcoil and Sclerosing Agent]

背景与目的

肺内小结节往往难以进行胸腔镜术中定位，需要术前计算机断层扫描（computed tomography, CT）引导经皮穿刺定位辅助，本研究旨在比较两种不同定位材料即微弹簧圈和硬化剂（聚桂醇）定位的效果及相关并发症，评价优劣。

方法

回顾性分析术前CT引导经皮穿刺定位患者371例，根据采用的不同定位材料分为：微弹簧圈组（microcoil group）167例，定位结节196枚、硬化剂组（sclerosing agent group）204例，定位结节239枚。统计分析两组定位效果、并发症、病理资料及手术方案等相关资料。

结果

微弹簧圈组定位失败率（2.4%）高于硬化剂组（0.5%）（P=0.011），硬化剂定位耗时明显短于微弹簧圈组[（18.78±6.91）min vs（11.99±3.77）min, P=0.000]，但微弹簧圈组较硬化剂组选择定位结节与胸膜间距离更深[（9.59±8.62）mm vs（8.13±6.49）mm, P=0.002]。总体并发症上微弹簧圈组显著高于硬化剂组（P=0.000），其中以气胸为主，通过相关危险因素分析提示不同定位方法是独立危险因子。手术方式以楔形切除为主，病理结果以非浸润性病变为主。

结论

微弹簧圈与硬化剂均是良好的术前定位材料，聚桂醇硬化剂较之微弹簧圈定位失败率更低、并发症更少，定位时长更短，操作简便且费用低廉，值得推广。

Micron-scale magnetic resonance imaging of both liquids and solids

We describe and demonstrate a novel apparatus for magnetic resonance imaging (MRI), suitable for imaging of both liquid and solid samples with micron-scale isotropic resolution. The apparatus includes a solenoidal radio-frequency microcoil with 170 μm inner diameter and a set of planar gradient coils, all wound by hand and supported on a series of stacked sapphire plates. The design ensures efficient heat dissipation during gradient pulses and also facilitates disassembly, sample changes, and reassembly. To demonstrate liquid state (1)H MRI, we present an image of polystyrene beads within CuSO4-doped water, contained within a capillary tube with 100 μm inner diameter, with 5.0 μm isotropic resolution. To demonstrate solid state (1)H MRI, we present an image of NH4Cl particles within the capillary tube, with 8.0 μm isotropic resolution. High-resolution solid state MRI is enabled by frequency-switched Lee-Goldburg decoupling, with an effective rotating frame field amplitude of 289 kHz. At room temperature, pulsed gradients of 4 T/m (i.e., 170 Hz/μm for (1)H MRI) are achievable in all three directions with currents of 10 A or less. The apparatus is contained within a variable-temperature liquid helium cryostat, which will allow future efforts to obtain MRI images at low temperatures with signal enhancement by dynamic nuclear polarization.

Susceptibility cancellation of a microcoil wound with a paramagnetic-liquid-filled copper capillary

Even though microcoils improve the sensitivity of NMR measurement of tiny samples, magnetic-field inhomogeneity due to the bulk susceptibility effect of the coil material can cause serious resonance-line broadening. Here, we propose to fabricate the microcoil using a thin, hollow copper capillary instead of a wire and fill paramagnetic liquid inside the capillary, so as to cancel the diamagnetic contribution of the copper. Susceptibility cancellation is demonstrated using aqueous solution of NiSO4. In addition, the paramagnetic liquid serves as coolant when it is circulated through the copper capillary, effectively transferring the heat generated by radiofrequency pulses.

Magnetic Resonance-guided Active Catheter Tracking

Several advantages of MR imaging compared with other imaging modalities have provided the rationale for increased attention to MR-guided interventions, including its excellent soft tissue contrast, its capability to show both anatomic and functional information, and no use of ionizing radiation. An important aspect of MR-guided intervention is to provide visualization and navigation of interventional devices relative to the surrounding tissues. This article focuses on the methods for MR-guided active tracking in catheter-based interventions. Practical issues about implementation of active catheter tracking in a clinical setting are discussed and several current application examples are highlighted.

The efficacy and long-term outcome of microcoil embolotherapy for acute lower gastrointestinal bleeding

OBJECTIVE

To evaluate the clinical efficacy as well as long-term clinical outcomes of superselective microcoil embolization for lower gastrointestinal bleeding (LGIB).

MATERIALS AND METHODS

Between 1997 and 2009, 26 patients with intended transcatheter embolotherapy for LGIB were retrospectively reviewed. Embolization was performed only when the catheter could be advanced to or distal to the mesenteric border of the bowel. The main purpose of our study was to assess technical success, recurrent bleeding rate and complications. We also evaluated the long-term clinical outcome, including late recurrent LGIB, bowel ischemia and the survival rate.

RESULTS

Twenty-two bleeding sources were in the territory of superior mesenteric artery and four in the inferior mesenteric artery. Technical success was achieved in 22 patients (84.6%). The target vessel of embolization was vasa recta in seventeen patients and marginal artery in the remaining five patients. Early rebleeding occurred in two patients (7.7%) and bowel ischemia in two patients, of whom the embolized points were both at the marginal artery. Delayed recurrent bleeding (> 30 days) occurred in two angiodysplasia patients. Five patients (19.2%) died within the first 30 days of intervention. Long-term follow-up depicted estimated survival rates of 58.2 and 43.1% after one, and five years, respectively.

CONCLUSION

Transcatheter embolotherapy to treat LGIB is effective with low rebleeding and ischemic complications. Considering the advanced age and complex medical problems of these patients, the minimal invasive embolotherapy may be used as both a primary and potentially definitive treatment of LGIB.

Preoperative microcoil embolization of the common hepatic artery for pancreatic body cancer

AIM: To evaluate safety and feasibility of microcoil embolization of the common hepatic artery under proper or distal balloon inflation in preoperative preparation for en bloc celiac axis resection for pancreatic body cancer.

METHODS: Fifteen patients (11 males, 4 females; median age, 67 years) with pancreatic body cancer involving the nerve plexus surrounding the celiac artery underwent microcoil embolization. To alter the total hepatic blood flow from superior mesenteric artery (SMA), microcoil embolization of the common hepatic artery (CHA) was conducted in 2 cases under balloon inflation at the proximal end of the CHA and in 13 cases under distal microballoon inflation at the distal end of the CHA.

RESULTS: Of the first two cases of microcoil embolization with proximal balloon inflation, the first was successful, but there was microcoil migration to the proper hepatic artery in the second. The migrated microcoil was withdrawn to the CHA by an inflated microballoon catheter. Microcoil embolization was successful in the other 13 cases with distal microballoon inflation, with no microcoil migration. Compact microcoil embolization under distal microballoon inflation created sufficient resistance against the vascular wall to prevent migration. Distal balloon inflation achieved the requisite 1 cm patency at the CHA end for vascular clamping. All patients underwent en bloc celiac axis resection without arterial reconstruction or liver ischemia.

CONCLUSION: To impede microcoil migration to the proper hepatic artery during CHA microcoil embolization, distal microballoon inflation is preferable to proximal balloon inflation.

Dual microcatheter retrograde transvenous obliteration of gastric varices: coil embolization as a substitute for balloon occlusion

Dual microcatheter retrograde transvenous obliteration (DMRTO) of gastric varices enables dual microcatheters to be advanced to the gastric varices themselves or to a site adjacent to the varices. The sclerosing agent is infused through the first microcatheter following coil embolization of the outflow vessels through the second microcatheter, which is placed several centimeters back from the varices. We present two cases of gastric varices in whom balloon-occluded retrograde transvenous obliteration failed, because of angulated gastrosubphrenic shunt in case 1 and a tortuous and elongated gastrorenal shunt in case 2. DMRTO successfully achieved eradication of the gastric varices in both cases.