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.

Image-Based Evaluation of Irradiation Effects in Brain Tissues by Measuring Absolute Electrical Conductivity Using MRI.

Radiation-induced injury is damage to normal tissues caused by unintentional exposure to ionizing radiation. Image-based evaluation of tissue damage by irradiation has an advantage for the early assessment of therapeutic effects by providing sensitive information on minute tissue responses in situ. Recent magnetic resonance (MR)-based electrical conductivity imaging has shown potential as an effective early imaging biomarker for treatment response and radiation-induced injury. However, to be a tool for evaluating therapeutic effects, validation of its reliability and sensitivity according to various irradiation conditions is required. We performed MR-based electrical conductivity imaging on designed phantoms to confirm the effect of ionizing radiation at different doses and on in vivo mouse brains to distinguish tissue response depending on different doses and the elapsed time after irradiation. To quantify the irradiation effects, we measured the absolute conductivity of brain tissues and calculated relative conductivity changes based on the value of pre-irradiation. The conductivity of the phantoms with the distilled water and saline solution increased linearly with the irradiation doses. The conductivity of in vivo mouse brains showed different time-course variations and residual contrast depending on the irradiation doses. Future studies will focus on validation at long-term time points, including early and late delayed response and evaluation of irradiation effects in various tissue types.

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.