Comprehensive CT Imaging Analysis of Primary Colorectal Squamous Cell Carcinoma: A Retrospective Study.

The aim of this study was to evaluate the findings of CT scans in patients with pathologically confirmed primary colorectal squamous-cell carcinoma (SCC). The clinical presentation and CT findings in eight patients with pathologically confirmed primary colorectal squamous-cell carcinoma were retrospectively reviewed by two gastrointestinal radiologists. Hematochezia was the most common symptom (n = 5). The tumors were located in the rectum (n = 7) and sigmoid colon (n = 1). The tumors showed circumferential wall thickening (n = 4), bulky mass (n = 3), or eccentric wall thickening (n = 1). The mean maximal wall thickness of the involved segment was 29.1 mm ± 13.4 mm. The degree of tumoral enhancement observed via CT was well enhanced (n = 4) or moderately enhanced (n = 4). Necrosis within the tumor was found in five patients. The mean total number of metastatic lymph nodes was 3.1 ± 3.3, and the mean short diameter of the largest metastatic lymph node was 16.6 ± 5.7 mm. Necrosis within the metastatic node was observed in six patients. Invasions to adjacent organs were identified in five patients (62.5%). Distant metastasis was detected in only one patient. In summary, primary SCCs that arise from the colorectum commonly present as marked invasive wall thickening or a bulky mass with heterogeneous well-defined enhancement, internal necrosis, and large metastatic lymphadenopathies.

Thermal Injury to the Subhepatic Appendix Following Percutaneous Ultrasound-Guided Radiofrequency Ablation for Hepatocellular Carcinoma: A Case Report.

We present the first documented case of a fistula between the treated zone and the appendix after RFA in a patient with HCC. Contrast-enhanced CT and MRI revealed a subcapsular hepatic nodule with image findings of HCC located adjacent to the ascending colon and cecum. An ultrasound-guided core needle biopsy was subsequently performed to distinguish between hepatic metastasis and HCC. Post-RFA imaging identified a low-attenuating ablated area adjacent to an air-filled appendix. The patient later experienced complications, including increased liver enzymes and an abscess at the ablation site. Imaging revealed a fistulous tract between the RFA zone and the appendix. Over the following months, the patient underwent conservative treatment involving intravenous antibiotics and repeated percutaneous drainage, exhibiting eventual symptom relief and an absence of the fistulous tract upon subsequent imaging. This case highlights the rare complications that can arise during RFA due to peculiar anatomical variations, such as a subhepatic appendix, resulting from midgut malrotation and previous surgery. It is imperative for operators to be cognizant of potential anatomical variations when considering RFA treatment, ensuring comprehensive pre-procedural imaging and post-procedure monitoring. This case also emphasizes the potential viability of nonoperative management in complex scenarios in which surgical interventions pose significant risks.

Estimation of brain tissue response by electrical stimulation in a subject-specific model implemented by conductivity tensor imaging.

Electrical stimulation such as transcranial direct current stimulation (tDCS) is widely used to treat neuropsychiatric diseases and neurological disorders. Computational modeling is an important approach to understand the mechanisms underlying tDCS and optimize treatment planning. When applying computational modeling to treatment planning, uncertainties exist due to insufficient conductivity information inside the brain. In this feasibility study, we performed in vivo MR-based conductivity tensor imaging (CTI) experiments on the entire brain to precisely estimate the tissue response to the electrical stimulation. A recent CTI method was applied to obtain low-frequency conductivity tensor images. Subject-specific three-dimensional finite element models (FEMs) of the head were implemented by segmenting anatomical MR images and integrating a conductivity tensor distribution. The electric field and current density of brain tissues following electrical stimulation were calculated using a conductivity tensor-based model and compared to results using an isotropic conductivity model from literature values. The current density by the conductivity tensor was different from the isotropic conductivity model, with an average relative difference |rD| of 52 to 73%, respectively, across two normal volunteers. When applied to two tDCS electrode montages of C3-FP2 and F4-F3, the current density showed a focused distribution with high signal intensity which is consistent with the current flowing from the anode to the cathode electrodes through the white matter. The gray matter tended to carry larger amounts of current densities regardless of directional information. We suggest this CTI-based subject-specific model can provide detailed information on tissue responses for personalized tDCS treatment planning.

Pleural Effusion after Hepatic Radiofrequency Ablation with Artificial Ascites: Clinical Spectrum and Significance.

PURPOSE: To retrospectively investigate incidence, clinical outcome, and risk factors of iatrogenic pleural effusion in patients with hepatic tumors undergoing radiofrequency (RF) ablation using artificial ascites (AA). MATERIALS AND METHODS: Patients (N = 163) who underwent RF ablation using AA were classified into pleural effusion and non-pleural effusion groups according to the presence of pleural effusion on immediate follow-up CT and chest radiograph after RF ablation. The pleural effusion group included asymptomatic and symptomatic subgroups. The incidence and subsequent clinical outcomes of patients developing pleural effusion after RF ablation were evaluated. RESULTS: Overall, 96 patients (58.9%) developed pleural effusion, which resolved in 4.4 d ± 3.1. Hospital length of stay in the pleural effusion group was longer than the non-pleural effusion group (6.5 d ± 2.6 vs 5.7 d ± 2.8, P < .01). The pleural effusion group had longer AA infusion time (P = .01), larger infused AA volume (P < .01), and longer ablation time (P < .01) than the non-pleural effusion group. Eighteen patients (18.8%) developed symptomatic pleural effusion and had a larger infused AA volume than asymptomatic patients with pleural effusion (P < .01). Pleural effusion duration and hospital length stay were also longer in the symptomatic pleural effusion subgroup than in the asymptomatic subgroup (P < .01). Infused AA volume was the only independent prognostic factor of pleural effusion duration in multivariate analysis (P = .038). CONCLUSIONS: Pleural effusion frequently occurs after RF ablation using AA. Although generally considered negligible, pleural effusion could be a clinical problem and prolong hospitalization. Therefore, operators should be careful not to infuse too much AA when performing RF ablation.

Multidetector CT findings differ between surgical grades of pancreatic fistula after pancreaticoduodenectomy.

OBJECTIVES: To define and correlate multidetector CT (MDCT) findings of pancreatic fistula after pancreaticoduodenectomy with surgical grading based on the 2016 Revised International Study Group of Pancreatic Fistula (ISGPF) classification. METHODS: Between May 2011 and December 2016, 235 patients with periampullary tumor underwent pancreaticoduodenectomy and postoperative MDCT. Patients were classified into three groups (clinically no pancreatic fistula (cNo-PF), grade B, and grade C) according to the ISGPF classification. MDCT images were retrospectively evaluated by two radiologists in consensus for the presence of pancreaticojejunostomy (PJ) dehiscence, PJ dehiscence diameter, PJ defect, acute necrotic collection (ANC), peripancreatic fluid collection, and imaging findings of complications. Categorical MDCT findings were compared among the three groups using Pearson's chi-square test, and PJ dehiscence diameter was compared using the Kruskal-Wallis test. RESULTS: There was no significant difference in patient demographics among the groups (cNo-PF = 133, grade B = 68, and grade C = 34), but the MDCT findings were significantly different regarding the presence of PJ dehiscence (p < 0.001), PJ defect (p < 0.001), ANC (p = 0.002), and imaging findings of total complications (p < 0.001). The diameters of PJ dehiscence were significantly different among the groups (cNo-PF [0.42 ± 1.54 mm], grade B [1.47 ± 2.33 mm], and grade C [5.38 ± 6.45 mm]) (p < 0.001). CONCLUSION: With respect to the presence of PF, postoperative MDCT findings may differ between surgical grading based on the ISGPF classification. KEY POINTS: • Regarding the presence of pancreatic fistula, the postoperative multidetector CT findings correlate well with surgical grading based on the International Study Group of Pancreatic Fistula classification. • Multidetector CT may provide reliable information to suggest pancreatic fistula after pancreaticoduodenectomy.

Effect of levan's branching structure on antitumor activity.

Levan produced from Microbacterium laevaniformans KCTC 9732 (M-levan) was isolated and treated with an inulinase to modify its branching structure. The chemical structures of levans were characterized, and the modified levans were applied on animal tumor cells to evaluate their antitumor activity. The GC-MS analysis indicated that beta-(2,1)-linked branches of M-levan were specifically hydrolyzed. As the ratio of applied inulinase to levan increased, the branching degree decreased proportionally. Sequential degrees of branching were obtained from 12.3 to 4.2%. Strong levan-induced inhibition of cell growth was detected on SNU-1 and HepG2 tumor cell lines. As the branching degree of M-levan reduced, antitumor activity on SNU-1 linearly decreased (r2=0.96). In HepG2, the antitumor activity rapidly dropped when the branching reached up to 9.3%, then slightly increased as the branching degree of M-levan further decreased. These results suggested that the branch structure would play a crucial role in levan's antitumor activity.

Antitumor activity of levan polysaccharides from selected microorganisms.

Levans were isolated from the cultures of Gluconoacetobacter xylinus (G-levan; Mw = 40,000), Microbacterium laevaniformans (M; Mw = 710,000), Rahnella aquatilis (R; Mw = 380,000), and Zymomonas mobilis (Z; Mw = 570,000). The levans were composed mainly of fructose residues when analyzed by TLC and HPLC, and their main backbones were beta-(2,6)-linkages with beta-(2,1)-branches by GC-MS and NMR. In the in vitro antitumor activity test of the levans against eight different tumor cell lines, relatively stronger activity was observed from the SNU-1 and HepG2. The M- (52.54-62.05%) and R-levan (52.15-58.58%) showed the significantly high activity against SNU-1, while M-levan showed the highest (49.93-61.82%) activity against HepG2. During the in vivo analysis of inhibitory activity of the levans against Sarcoma-180 growth, M-, R- and Z-levans showed strong antitumor activity (average 66%) but G-levan (42%) had significantly lower activity.