Application of artificial intelligence using a convolutional neural network for detecting gastric cancer in endoscopic images

Background

Image recognition using artificial intelligence with deep learning through convolutional neural networks (CNNs) has dramatically improved and been increasingly applied to medical fields for diagnostic imaging. We developed a CNN that can automatically detect gastric cancer in endoscopic images.

Methods

A CNN-based diagnostic system was constructed based on Single Shot MultiBox Detector architecture and trained using 13,584 endoscopic images of gastric cancer. To evaluate the diagnostic accuracy, an independent test set of 2296 stomach images collected from 69 consecutive patients with 77 gastric cancer lesions was applied to the constructed CNN.

Results

The CNN required 47 s to analyze 2296 test images. The CNN correctly diagnosed 71 of 77 gastric cancer lesions with an overall sensitivity of 92.2%, and 161 non-cancerous lesions were detected as gastric cancer, resulting in a positive predictive value of 30.6%. Seventy of the 71 lesions (98.6%) with a diameter of 6 mm or more as well as all invasive cancers were correctly detected. All missed lesions were superficially depressed and differentiated-type intramucosal cancers that were difficult to distinguish from gastritis even for experienced endoscopists. Nearly half of the false-positive lesions were gastritis with changes in color tone or an irregular mucosal surface.

Conclusion

The constructed CNN system for detecting gastric cancer could process numerous stored endoscopic images in a very short time with a clinically relevant diagnostic ability. It may be well applicable to daily clinical practice to reduce the burden of endoscopists.

     

The role of the sympathetic nervous system in radiation-induced apoptosis in jejunal crypt cells of spontaneously hypertensive rats

To evaluate the effect of the sympathetic nervous system on radiation-induced apoptosis in jejunal crypt cells, apoptosis levels were compared in spontaneously hypertensive rats (SHR), animals which are a genetic hyperfunction model of the sympathetic nervous system, and normotensive Wistar-Kyoto rats (WKY). SHR and WKY were exposed to whole body X-ray irradiation at doses from 0.5 to 2 Gy. The apoptotic index in jejunal crypt cells was significantly greater in SHR than in WKY at each time point after irradiation and at each dose. WKY and SHR were treated with reserpine to induce sympathetic dysfunction, and were subsequently exposed to irradiation. Reserpine administration to SHR or WKY resulted in a significant suppression of apoptosis. p53 accumulation was detected in the jejunum in both WKY and SHR after irradiation by Western blotting analysis. There were no significant differences in the levels of p53 accumulation in irradiated intestine between WKY and SHR. These findings suggested that hyperfunction of the sympathetic nervous system is involved in the mechanism of high susceptibility to radiation-induced apoptosis of the jejunal crypt cells.     

CT-controlled stereotactic operations for hypertensive intracerebral hemorrhage Part 2: Cases with small hematomas in the thalamus and the basal ganglia

Theoretical principles and actual operative procedures of "CT-controlled stereotactic operations," which was invented by us, have been reported in the previous paper of part 1. In this paper, it is reported 9 cases, 5 of putaminal hemorrhage and 4 of thalamic hemorrhage, who underwent CT-controlled stereotactic operations for evacuation of their small hematomas. Eight patients were male and one patient was female. The age of patients ranged from 42 to 75 years, with a mean age of 62.7 years and there were 3 patients of over 70 years old. And there were 2 patients with poor general condition preoperatively; one had the implantation of pacemaker because of Adams-Stokes syndrome 5 years ago and the other had total gastrectomy because of gastric neoplasm 1 month ago. Eight cases were in acute stage within three days after the onset. Mean operative timing was 14.6 hrs. after the onset. It was very interesting that three cases, 2 of putaminal and 1 of thalamic hemorrhage, had recovered dramatically by this surgery, just like the course after the hematoma evacuation in cases of chronic subdural hematoma. Namely their hemiparesis are decreased remarkably within a few hours after hematoma evacuation. Practically this surgery has minimum risk with simple procedures. The hematoma evacuation can be done easily with high accuracy of stereotaxy. From our experience, potential usefulness of this surgery was positively suggested in the surgical treatment for small ganglionic hematomas as well as thalamic hematomas.     

Primary small-cell neuroendocrine carcinoma of the breast: Report of a case

Primary small-cell neuroendocrine carcinoma of the breast is a rare and aggressive neoplasm without an established treatment protocol because so few cases have been described. We report a case of primary smallcell neuroendocrine carcinoma in a 31-year-old woman. The patient came to our hospital 10 days after consulting another clinic, where a diagnosis of locally advanced breast cancer suitable for neoadjuvant chemotherapy had been made. Core needle biopsy under ultrasonographic guidance revealed invasive carcinoma. The doubling time of the tumor progression was calculated as 12 days based on ultrasonographic measurement. After three cycles of chemotherapeutic regimens consisting of adriamycin plus docetaxel, the disease was judged to be progressive and the patient underwent surgery. Definitive histopathological examination revealed primary small-cell neuroendocrine carcinoma. Local and mediastinal recurrence with multiple liver metastases developed only 5 weeks after surgery. Cisplatin plus irinotecan combination chemotherapy was started; however, the patient died of aggressive recurrent tumor progression 6 months after surgery, in spite of the transient tumor regression achieved by chemotherapy. This case reinforces the importance of an early correct diagnosis and the standardization of a treatment regimen for this very rare tumor.     

Experimental rat pancreas transplant: Surgical technique and immunological considerations

Vascularized whole pancreas transplantation in the rat was performed on the abdomen using a cuff technique for vascular anastomoses. Two different exocrine drainage procedures, either intestinal or ureter drainage, were used. In the isograft transplant models, hyperglycemia was ameliorated immediately after transplantation and all of the grafts functioned during the observation period. In the allograft transplant models without immunosuppression, graft rejection, as defined by recurrence of hyperglycemia (blood glucose >200 mg/dl) occurred 6–9 days post-transplant. Allograft rejection could be delayed approximately 1 month after transplant with short-term use of FK506. These different models, using either intestinal or ureter exocrine drainage, are similar to dominant clinical pancreas transplantation with enteric exocrine drainage or urinary tract drainage, respectively. It is thus concluded that whole pancreas transplant with either intestinal or ureter exocrine drainage is an ideal model for physiological and immunological experimental studies in pancreas transplantation.     

Phase II study of personalized peptide vaccination for refractory bone and soft tissue sarcoma patients

Refractory bone and soft tissue sarcomas are challenging diseases to treat because of their robustness to chemotherapy. Although cancer vaccines have the potential to become an attractive treatment modality, their progress has been hampered by the presence of many subtypes of sarcomas and different human leukocyte antigen (HLA)‐types. We investigated whether personalized peptide vaccination (PPV) would be feasible for the vast majority of sarcoma patients. Twenty refractory bone and soft tissue sarcoma patients with nine different subtypes and 11 different HLA‐class IA phenotypes were enrolled in this study. A maximum of four HLA‐matched peptides showing higher peptide‐specific IgG responses in pre‐vaccination plasma were selected from 31 pooled peptide candidates applicable for the HLA‐A2, ‐A3, ‐A11, ‐A24, ‐A26, ‐A31, and ‐A33 types, and were subcutaneously administered weekly for 6 weeks and bi‐weekly thereafter. Measurement of peptide‐specific CTL and IgG responses along with other laboratory analyses were conducted before and after vaccination. No patients were excluded by either sarcoma subtypes or different HLA‐types. No severe adverse events associated with PPV were observed in any patients. Peptide‐specific immunological boosting was observed in the post‐vaccination samples from the majority of patients. Tumor reduction of the lung metastasis and a long stable disease was observed in each case, and the median overall survival time of the 20 cases was 9.6 months. Taken together, PPV could be feasible for the vast majority of refractory sarcoma patients because of the safety and higher rates of immunological responses regardless of the presence of different sarcoma subtypes and various HLA‐types.