Feasibility of utilizing ultra-low-dose contrast medium for pancreatic artery depiction using the combination of advanced virtual monoenergetic imaging and high-concentration contrast medium: an intra-patient study

Objectives The least amount of contrast medium (CM) should be used under the premise of adequate diagnosis. The purpose of this study is to evaluate the feasibility of utilizing ultra-low-dose (224 mgI/kg) CM for pancreatic artery depiction using the combination of advanced virtual monoenergetic imaging (VMI+) and high-concentration (400 mgI/mL) CM. Materials and methods 41 patients who underwent both normal dose CM (ND-CM, 320 mgI/kg) and low dose CM (LD-CM, 224 mgI/kg) thoracoabdominal enhanced CT for tumor follow-up were prospectively included. The VMI+ at the energy level of 40-kev for LD-CM images was reconstructed. CT attenuation, signal-to-noise ratios (SNRs), and contrast-to-noise ratios (CNRs) of the abdominal artery, celiac artery, and superior mesenteric artery (SMA) and qualitative scores of pancreatic arteries depiction were recorded and compared among the three groups (ND-CM, LD-CM, and VMI+ LD-CM images). ANOVA and Friedman tests were used for statistical analysis. Results All quantitative and qualitative parameters on LD-CM images were lower than that on ND-CM images (all p < 0.01). There were no significant differences of all arteries’ qualitative scores between ND-CM and VMI+ LD-CM images (all p > 0.05). VMI+ LD-CM images had the highest mean CT and CNR values of all arteries (all p < 0.0001). The CM volume was 52.6 ± 9.4 mL for the ND-CM group and 37.0 ± 6.7 mL for the LD-CM group. Conclusion Ultra-low-dose CM (224 mgI/kg) was feasible for depicting pancreatic arteries. Inferior angiographic image quality could be successfully compensated by VMI+ and high-concentration CM.

Efficacy of navigating through the intraplaque route using AnteOwl WR intravascular ultrasound in femoropopliteal chronic total occlusion

Background There is no consensus on the optimal guidewire passage route for femoropopliteal (FP) chronic total occlusion (CTO). If intraplaque wiring can be performed, a stent-less strategy using a drug-coated balloon can be realized even with FP CTO, and there is a high possibility that good expansion can be obtained even when stent deployment is performed. AnteOwl WR (AnteOwl) is a novel intravascular ultrasound (IVUS) device useful for navigating the second guidewire into the intraplaque route under IVUS observation from the subintimal space. Here, we describe representative cases of FP CTO in which CTO-specific IVUS was extremely useful. Case presentation Case 1 involved a 79-year-old man with total occlusion of the left superficial femoral artery (SFA). We used a contralateral antegrade approach, but the guidewire was advanced into the subintimal space. We advanced AnteOwl into the CTO. By utilizing the asymmetric structure of the transducer and the IVUS wire, we were able to reflect the positional relationship among the IVUS transducer, IVUS wire, and target plaque onto the angiographic image. By aiming the wiring in that direction, we succeeded in traversing the center of the plaque and finally succeeded in obtaining good expansion using the drug-coated balloon. Case 2 involved a 76-year-old woman with total occlusion from the SFA to the popliteal artery. We used an ipsilateral antegrade approach. When AnteOwl was placed on the wire and advanced to the popliteal artery, the subintimal space in the middle of the SFA could be visualized. We employed an IVUS-guided parallel wiring technique and succeeded in passing through all intraplaque routes. Although the CTO was long, we could easily advance through the intraplaque route by reflecting the information obtained from AnteOwl in angiography. Conclusions AnteOwl is an effective IVUS for FP CTO and facilitates a complex IVUS-guided procedure.

Deep neuromuscular block improves angiographic image quality during endovascular coiling of unruptured cerebral aneurysm: a randomized clinical trial

BackgroundNeuromuscular block (NMB) used during general anesthesia induces transient skeletal muscle paralysis, but patient movements during endovascular coiling still occur to some degree. Compared with moderate NMB, deep NMB may further improve the intervention condition during endovascular coiling for unruptured cerebral aneurysms; however, little research has focused on the angiographic image quality.MethodsThis prospective, randomized, double-blind clinical trial included 58 patients treated for unruptured cerebral aneurysms with endovascular coiling under general anesthesia. Patients were randomly allocated to either the deep NMB group (post-tetanic count 1 or 2) or the moderate NMB group (train-of-four 1 or 2). The primary outcome was the proportion of patients with a satisfactory intervention condition assessed by surgeons after the procedure using a 5-point intervention condition rating scale (ICRS) from 1 (unable to obtain image) to 5 (optimal); ICRS 5 was defined as satisfactory.ResultsThere were significantly more cases of satisfactory intervention condition in the deep NMB group than in the moderate NMB group (82.1% vs 51.7%, p=0.015). The frequency of each ICRS score was significantly different between the groups (ICRS 5/4/3/2/1: 23/5/0/0/0 vs 15/9/2/3/0, p=0.035). The incidence of major patient movement requiring rescue muscle relaxant was 10.3% in the moderate NMB group and 0% in the deep NMB group (p=0.237). The drugs used to maintain hemodynamic stability were not significantly different between the two groups.ConclusionsDeep NMB improves the intervention condition during endovascular coiling by improving the image quality.

Inter/intra-frame constrained vascular segmentation in X-ray angiographic image sequence

Background Automatic vascular segmentation in X-ray angiographic image sequence is of crucial interest, for instance, for better quantifying coronary arteries in diagnostic and interventional procedures. Methods A novel inter/intra-frame constrained vascular segmentation method is proposed to automatically segment vessels in coronary X-ray angiographic image sequence. First, a morphological filter operator is applied to remove structures undergoing the respiratory motion from the original image sequence. Second, an inter-frame constrained robust principal component analysis (RPCA) is utilized to remove the quasi-static structures from the image sequence. Third, an intra-frame constrained RPCA is employed to smooth the final extracted vascular sequence. Fourth, a multi-feature fusion is designed to improve the vascular contrast and the final vascular segmentation is realized by thresholding-based method. Results Experiments are conducted on 22 clinical X-ray angiographic image sequences. The global and local contrast-to-noise ratio of the proposed method are 6.6344 and 4.2882, respectively. And the precision, sensitivity and F1 value are 0.7378, 0.7960 and 0.7658, respectively. It demonstrates that our method is effective and robust for vascular segmentation from image sequence. Conclusions The proposed method is effective to remove non-vascular structures, reduce motion artefacts and other non-uniform illumination caused noises. Also, the proposed method is online which can just process one image per time without re-optimizing the model.