[Effects of Subject Position on Metal Artifact Reduction of a Reverse Shoulder Prosthesis Using Computed Tomography].

PURPOSE: To validate the effects of subject position on single energy metal artifact reduction (SEMAR) of a reverse shoulder prosthesis using computed tomography (CT). METHODS: A water phantom with a reverse shoulder prosthesis was scanned at four positions on the XY plane of the CT gantry (on-center, 50 mm, 100 mm, and 150 mm from on-center in the negative direction of the X axis, respectively). We obtained images with and without SEMAR. The artifact index (AI) was measured via physical assessment. Scheffé's (Ura) paired comparison methods were performed with the amount of metal artifact by ten radiological technologists via visual assessment. RESULTS: The AI was significantly reduced when using SEMAR. As the phantom moved away from the on-center position, the AI increased, and metal artifacts increased in Scheffé's methods. CONCLUSION: SEMAR reduces metal artifacts of a reverse shoulder prosthesis, but metal artifacts may increase as the subject position moves away from the on-center position.

[New Method of Paired Comparison for Improved Observer Shortage Using Deep Learning Models].

PURPOSE: The aim of this study was to validate the potential of substituting an observer in a paired comparison with a deep-learning observer. METHODS: Phantom images were obtained using computed tomography. Imaging conditions included a standard setting of 120 kVp and 200 mA, with tube current variations ranging from 160 mA, 120 mA, 80 mA, 40 mA, and 20 mA, resulting in six different imaging conditions. Fourteen radiologic technologists with >10 years of experience conducted pairwise comparisons using Ura's method. After training, VGG16 and VGG19 models were combined to form deep learning models, which were then evaluated for accuracy, recall, precision, specificity, and F1value. The validation results were used as the standard, and the results of the average degree of preference and significance tests between images were compared to the standard if the results of deep learning were incorporated. RESULTS: The average accuracy of the deep learning model was 82%, with a maximum difference of 0.13 from the standard regarding the average degree of preference, a minimum difference of 0, and an average difference of 0.05. Significant differences were observed in the test results when replacing human observers with AI counterparts for image pairs with tube currents of 160 mA vs. 120 mA and 200 mA vs. 160 mA. CONCLUSION: In paired comparisons with a limited phantom (7-point noise evaluation), the potential use of deep learning was suggested as one of the observers.

[Effects of Changing the Source-to-image Receptor Distance Parameter of Scattered X-ray Correction after Exposure on Image Quality in Portable Chest Radiography].

PURPOSE: To validate the effects of changing the source-to-image receptor distance (SID) parameter of scattered X-ray correction after exposure on the image quality in portable chest radiography. METHODS: The actual SID and tube current-time product (mAs) were varied such that the direct X-ray dose to a flat panel detector (FPD) remained constant. We created two groups as follows: Group A (with the SID parameter unchanged) and Group B (with the SID parameter changed to the actual SID after a phantom chest exposure). The image contrast ratio and standard deviation (SD) were measured on the chest radiographs for physical assessment. Observer studies were performed by seven radiological technologists. Scheffé's (Ura) paired comparison methods were performed with image contrast, noise, and overall assessment as the assessment items. Receiver operating characteristic (ROC) analysis for lung nodules was performed. RESULTS: The image contrast ratio and SD in Group A changed, whereas the changes in Group B were less than those in Group A for both these properties. The observer study with Scheffé's methods showed a statistically significant difference (p<0.05) for all assessment items in Group A but not in Group B. The ROC analysis did not indicate any statistically significant differences in either group. CONCLUSION: Changing the SID parameter of scattered X-ray correction after exposure can possibly maintain image contrast and noise in portable chest radiography if the actual SID changes.

The 1-year outcomes after pancreaticogastrostomy using vertical versus horizontal mattress suturing for gastric wrapping.

PURPOSE: To investigate the differences in nutritional status 1 year after pancreaticogastrostomy (PG) using vertical suturing (VS) vs. twin square horizontal mattress (HMS) suturing in patients undergoing pancreaticoduodenectomy (PD). METHODS: The subjects of this study were 134 patients who underwent PD, followed by PG, which was closed by VS in 52 and by HMS in 82. We evaluated the peri- and postoperative factors, nutritional parameters, diameter of the remnant main pancreatic duct, and glucose intolerance 1 year postoperatively. RESULTS: Forty-five (87%) patients from the VS group and 75 (91%) patients from the HMS group survived for more than 1 year. The incidences of intraabdominal abscess and pancreatic fistula were significantly lower in the HMS group than in the VS group (19.2% vs. 6.6% and19.2% vs. 2.6%, respectively). There were no significant changes in the total protein, serum albumin, and HbA1c levels 1 year postoperatively. The postoperative expansion ratio of the main pancreatic duct diameter was significantly smaller in the HMS group than in the VS group. The strongest risk factor for body weight loss 1 year postoperatively was a non-soft pancreas texture. CONCLUSION: HMS was superior to VS for preventing early postoperative complications and did not affect pancreatic function.

[A Case of Fournier's Gangrene Due to Perforation of Lower Rectal Cancer during Chemotherapy].

Fournier's gangrene is a rapidly progressing bacterial infection, involving the subcutaneous and deep fascia. Although intestinal perforation after treatment with bevacizumab is well known, Fournier's gangrene rarely occurs during chemotherapy. A 73-year-old man with unresectable rectal cancer during chemotherapy involving the mFOLFOX6 plus bevacizumab regimen had a consciousness disorder and was admitted to our hospital on emergency. Computed tomography scans indicated a necrotizing soft tissue infection with large amounts of pneumoderma throughout the perineum. He was diagnosed as having Fournier's gangrene via perforation of rectal cancer, and urgent operation was performed. After debridement of the skin and soft tissue around the perineum, loop sigmoidostomy was performed. A nice granulated tissue bed over the perineum was formed via daily lavage with sarin. Although the patient was taken back to the operation theater for ileostomy, he could resume chemotherapy involving mFOLFOX6 without bevacizumab 50 days after the initial operation. It is necessary to pay attention to Fournier's gangrene via perforation during chemotherapy with bevacizumab in patients with lower rectal cancer.

Comparison of Arterial Spin-labeling Perfusion Images at Different Spatial Normalization Methods Based on Voxel-based Statistical Analysis.

PURPOSE: Spatial normalization is a significant image pre-processing operation in statistical parametric mapping (SPM) analysis. The purpose of this study was to clarify the optimal method of spatial normalization for improving diagnostic accuracy in SPM analysis of arterial spin-labeling (ASL) perfusion images. METHODS: We evaluated the SPM results of five spatial normalization methods obtained by comparing patients with Alzheimer's disease or normal pressure hydrocephalus complicated with dementia and cognitively healthy subjects. We used the following methods: 3DT1-conventional based on spatial normalization using anatomical images; 3DT1-DARTEL based on spatial normalization with DARTEL using anatomical images; 3DT1-conventional template and 3DT1-DARTEL template, created by averaging cognitively healthy subjects spatially normalized using the above methods; and ASL-DARTEL template created by averaging cognitively healthy subjects spatially normalized with DARTEL using ASL images only. RESULTS: Our results showed that ASL-DARTEL template was small compared with the other two templates. Our SPM results obtained with ASL-DARTEL template method were inaccurate. Also, there were no significant differences between 3DT1-conventional and 3DT1-DARTEL template methods. In contrast, the 3DT1-DARTEL method showed higher detection sensitivity, and precise anatomical location. CONCLUSIONS: Our SPM results suggest that we should perform spatial normalization with DARTEL using anatomical images.

[A Case of Esophageal Cancer in a Patient with CMV Reactivation after Neoadjuvant Chemoradiation Therapy].

A 68-year-old woman was diagnosed with advanced esophageal cancer with lymph node metastasis, for which she received neoadjuvant chemoradiotherapy. During therapy, she had loss of appetite and weight; therefore, we inserted a nasal feeding tube for her nutrition, after which, she gained weight soon. After therapy, she had a high fever with lymphocytopenia and was diagnosed with cytomegalovirus infection because of significantly high CMV antigenemia. Ganciclovir was administered immediately, and she recovered soon. Two months later, we performed esophagectomy, and she recovered without complications. Immediate diagnosis of CMV infection, ganciclovir administration, and nutrition through a feeding tube were useful for the esophageal cancer patient in this report who had immunosuppression and malnutrition during chemoradiation.

Impaired wound healing and expansion of a large ulcer after bevacizumab with paclitaxel for skin metastases from breast cancer: report of a case.

A 48-year-old Japanese woman was found to have local recurrence of breast cancer in the chest wall following neoadjuvant chemotherapy, total mastectomy with axillary lymphadenectomy, postoperative radiation therapy to the chest wall, and adjuvant systemic therapy using trastuzumab. As a third line of treatment after recurrence, bevacizumab with paclitaxel was initiated for several metastatic lesions on the skin of the chest wall, left internal costal lymph nodes, and right axillary lymph nodes. The wound on the chest wall continued to expand in diameter and depth after the third course of bevacizumab with paclitaxel until the rib was exposed. After stopping the bevacizumab, granulation tissue expanded and by 3 months, had covered the bottom of the ulcer. The patient died soon thereafter, despite systemic chemotherapy with eribulin; however, there was no further bleeding from the ulcer on the chest wall or the exposed ribs.

[A case of esophageal cancer with septic disseminated intravascular coagulation treated with recombinant human soluble thrombomodulin during chemoradiation therapy].

A 70-year-old woman was diagnosed with synchronous advanced esophageal cancer and early renal cancer. During chemoradiation therapy for the esophageal cancer, she suffered from septic shock due to pneumonia. She got worse despite the administration of antibiotics and gglobulin. On the following day, she was diagnosed with septic disseminated intravascular coagulation(DIC)on the basis of the diagnostic criterion for acute DIC. Recombinant human soluble thrombomodulin(rTM) was administered to treat the DIC. The patient responded promptly to rTM treatment and recovered from the DIC in just 1 day. rTM is thought to be an effective drug for sepsis-induced DIC during chemoradiation therapy.