Kazuhiro Furukawa

Diagnosis of the Invasion Depth of Gastric Cancer Using MDCT With Virtual Gastroscopy: Comparison With Staging With Endoscopic Ultrasound

OBJECTIVE The objectives of this study were to retrospectively evaluate the lesion detection rate of gastric cancer using only virtual gastroscopy generated from MDCT images and the accuracy of invasion depth diagnosis (T staging) using virtual gastroscopy together with contrast-enhanced MDCT with multiplanar reconstruction (MPR) images (virtual gastroscopy with MPR), and to compare the diagnostic performance between virtual gastroscopy with MPR images and endoscopic ultrasound. MATERIALS AND METHODS The subjects consisted of 175 patients with a total of 186 endoscopically proven gastric cancer lesions. All patients underwent dynamic MDCT (arterial and venous phase) for preoperative staging and underwent surgery or endoscopic treatment. In 129 patients (135 lesions) who were also examined using endoscopic ultrasound, the T staging accuracy was also compared between the two modalities. Two endoscopists independently evaluated the lesion detection rate on virtual gastroscopy images alone and determined the T stage on virtual gastroscopy with MPR images. The T staging included the ability to differentiate T1a from T1b lesions. RESULTS The overall lesion detection rate was 67.7% (126/186). The detection rates of T1a, T1b, and T2 or deeper were 37.8% (28/74), 75.0% (39/52), and 98.3% (59/60), respectively, showing statistically significant differences (p < 0.001). The T staging accuracies were 82.2% (111/135) using virtual gastroscopy with MPR images and 83.7% (113/135) using endoscopic ultrasound, showing no statistically significant difference (p = 0.850). The main causes of over- and understaging were an ulcer or ulcer scar and poorly differentiated adenocarcinomas, non-solid type, respectively. CONCLUSION Virtual gastroscopy with MPR imaging is a useful modality in the T staging of gastric cancer.

Organ segmentation from 3d abdominal CT images based on atlas selection and graph cut

This paper presents a method for segmenting abdominal organs from 3D abdominal CT images based on atlas selection and graph cut. The training samples are divided into multiple clusters based on the image similarity. The average image and atlas for each cluster are created. For an input image, we select the most similar atlas to the input image by measuring the image similarity between the input and average images. Segmentation of organs based on the MAP estimation using the selected atlas is then performed, followed by the precise segmentation by the graph cut algorithm. We applied the proposed method to a hundred cases of CT images. The experimental results showed that the extraction accuracy could be improved using multiple atlases, achieving more than 90% of the precision rate except for the pancreas.

Simplified magnetic anchor-guided endoscopic submucosal dissection in dogs (with videos)

BACKGROUND Magnetic anchor-guided endoscopic submucosal dissection (MAG-ESD) was developed to reduce adverse events such as bleeding and perforation and to facilitate ESD. However, the external electromagnet required miniaturization to make it suitable for daily clinical practice. OBJECTIVE To evaluate the feasibility of simplified MAG-ESD using permanent magnets. DESIGN Case series. SETTING Nagoya University Hospital. SUBJECTS Beagle dogs. INTERVENTIONS The simplified MAG-ESD was performed on 10 representative areas of the stomachs of beagle dogs. The magnetic anchor consisted of an internal magnet attached to a hemoclip. The external and internal magnets were made from the rare earth neodymium. MAIN OUTCOME MEASUREMENTS The feasibility of countertraction with good visualization using simplified MAG-ESD. The rate of perforation, the time required for preparation, and attaching the magnetic anchor were also evaluated. RESULTS All lesions were successfully resected without perforation. The magnetic anchor could be controlled easily, and direct visualization was maintained by adequate counter traction. Preparing the magnetic anchor and grasping the mucosal edge using the hemoclip was easy and required a median of only 4 minutes (range, 2-7 minutes). LIMITATIONS Animal experiment, low number and lesion size. CONCLUSIONS This simplified MAG-ESD is feasible and allowed excellent visualization in the dog stomach. The feasibility of this system should be assessed in humans.

Usefulness of Helicobacter pylori eradication for precancerous lesions of the gastric remnant.

Secondary stomach cancer in lesions of the remnant stomach occurs relatively soon after distal gastrectomy using the Billroth I reconstruction procedure. Prophylactic eradication of Helicobacter pylori after endoscopic resection of early gastric cancer should be used to prevent the development of metachronous gastric carcinoma. However, the effect of H. pylori eradication on the gastric remnant has not been clearly determined.

Preliminary study on evaluation of the pancreatic tail observable limit of transabdominal ultrasonography using a position sensor and CT-fusion image

BACKGROUND AND AIM Transabdominal ultrasonography (US) is commonly used for the initial screening of bilio-pancreatic diseases in Asian countries due to its widespread availability, the non-invasiveness and the cost-effectiveness. However, it is considered that US has limits to observe the area, namely the blind area. The observation of the pancreatic tail is particularly difficult. The goal of this study was to examine the pancreatic tail region that cannot be visualized on transverse scanning of the upper abdomen using US with spatial positional information and factors related to visualization, and observation of the tail from the splenic hilum. METHODS Thirty-nine patients with pancreatic/biliary tract disease underwent CT and US with GPS-like technology and fusion imaging for measurement of the real pancreatic length and the predicted/real unobservable (PU and RU) length of the pancreatic tail. RU from US on transverse scanning and the real pancreatic length were used to determine the unobservable area (UA: RU/the real pancreatic length). Relationships of RU with physical and hematological variables that might influence visualization of the pancreatic tail were investigated. RESULTS The real pancreatic length was 160.9 ± 16.4mm, RU was 41.0 ± 17.8mm, and UA was 25.3 ± 10.4%. RU was correlated with BMI (R=0.446, P=0.004) and waist circumferences (R=0.354, P=0.027), and strongly correlated with PU (R=0.788, P<0.001). The pancreatic tail was visible from the splenic hilum in 22 (56%) subjects and was completely identified in 13 (33%) subjects. CONCLUSIONS Combined GPS-like technology with fusion imaging was useful for the objective estimation of the pancreatic blind area.

Automatic abdominal lymph node detection method based on local intensity structure analysis from 3D x-ray CT images

This paper presents an automated method of abdominal lymph node detection to aid the preoperative diagnosis of abdominal cancer surgery. In abdominal cancer surgery, surgeons must resect not only tumors and metastases but also lymph nodes that might have a metastasis. This procedure is called lymphadenectomy or lymph node dissection. Insufficient lymphadenectomy carries a high risk for relapse. However, excessive resection decreases a patients quality of life. Therefore, it is important to identify the location and the structure of lymph nodes to make a suitable surgical plan. The proposed method consists of candidate lymph node detection and false positive reduction. Candidate lymph nodes are detected using a multi-scale blob-like enhancement filter based on local intensity structure analysis. To reduce false positives, the proposed method uses a classifier based on support vector machine with the texture and shape information. The experimental results reveal that it detects 70.5% of the lymph nodes with 13.0 false positives per case.

Meiosis specific transcription and functional proteins

We have discussed and/or demonstrated the following: 1. Many enzymes and structural proteins have been identified as meiosis-specific proteins. These can be classified according to their metabolic behavior. 2. We obtained and analyzed 18 cDNA clones from lily meiocytes. One of them, LIM15, was similar to known genes like RecA, RAD57, and DMC1/ISC2, and might function in pairing and recombination. 3. Transcription of these genes is regulated by their regulator region(s). When such a regulator, mei2 promoter sequence isolated from S. pombe, was ligated with the proper vector and transfected, it functioned specifically in meiotic cells but not in the somatic cells tested. 4. Presence of a new lamin, lamin B3 was identified in mammalian spermatocytes and the transfection of lamin B3 gene (inserted into vector) into somatic cells alters the nuclear shape, possibly expressing a characteristic shape of meiotic nuclei. Lamin B3 was synthesized after meiosis-specific processing of lamin B2 mRNA. Other protein specific to meiotic nuclear-skeleton (MNS1) were found and characterized. All these events were studied basically focussing on homologous pairing and recombination which take place in meiosis I. We recognize the necessity of further studies on these and other events like the structure and segregation of chromosomes and the suppression of somatic gene expression during meiosis.

Clinical factors related to false-positive rates of patency capsule examination

Background Retention is the most common complication of capsule endoscopy (CE), and is reported to occur in 0–13% of cases. To avoid retention, a PillCam patency capsule (PC) is used in patients with suspected intestinal stenosis. However, a relatively low positive predictive value of the PC examination has been reported previously. The aims of this study were to clarify the accuracy of PC examination and to evaluate clinical factors related to cases of false-positive detection. Methods We performed a retrospective single-center study of 282 consecutive patients referred for PC examination. Patients in which the PC could not pass through the small bowel within 33 h were classified into the ‘no patency’ group. The ‘no patency’ group was investigated for evidence of significant stenosis upon further examinations, including CE, double-balloon endoscopy, and small bowel follow-through after PC examination. Clinical factors related to small bowel patency and false-positive cases were evaluated. Results We included 161 male (57.1%) and 121 female (42.9%) patients with a mean age of 47.5 ± 17.7 years. Of the 282 patients enrolled, 27 patients exhibited ‘no patency’ upon PC examination. Multivariate analysis showed that clinical factors related to ‘no patency’ included Crohn’s disease, abdominal symptoms, stenosis upon imaging, and previous abdominal surgery. Upon further examination, nine cases in the ‘no patency’ group had significant stenosis. Sensitivity, specificity, and negative and positive predictive values of PC examination for detecting small bowel stenosis were 93.8%, 96.6%, 99.6%, and 62.5%, respectively, and the only clinical factor related to false-positive cases was constipation (p < 0.05). Conclusion We found a relatively low positive predictive value of PC examination and that constipation was related to false-positive results. To extend the implications of CE indications, clinical study focusing on these results is expected.

Colonoscope navigation system using colonoscope tracking method based on line registration

This paper presents a new colonoscope navigation system. CT colonography is utilized for colon diagnosis based on CT images. If polyps are found while CT colonography, colonoscopic polypectomy can be performed to remove them. While performing a colonoscopic examination, a physician controls colonoscope based on his/her experience. Inexperienced physicians may occur complications such as colon perforation while colonoscopic examinations. To reduce complications, a navigation system of colonoscope while performing the colonoscopic examinations is necessary. We propose a colonoscope navigation system. This system has a new colonoscope tracking method. This method obtains a colon centerline from a CT volume of a patient. A curved line (colonoscope line) representing the shape of colonoscope inserted to the colon is obtained by using electromagnetic sensors. A coordinate system registration process that employs the ICP algorithm is performed to register the CT and sensor coordinate systems. The colon centerline and colonoscope line are registered by using a line registration method. The position of the colonoscope tip in the colon is obtained from the line registration result. Our colonoscope navigation system displays virtual colonoscopic views generated from the CT volumes. A viewpoint of the virtual colonoscopic view is a point on the centerline that corresponds to the colonoscope tip. Experimental results using a colon phantom showed that the proposed colonoscope tracking method can track the colonoscope tip with small tracking errors.

Automated abdominal lymph node segmentation based on RST analysis and SVM

This paper describes a segmentation method for abdominal lymph node (LN) using radial structure tensor analysis (RST) and support vector machine. LN analysis is one of crucial parts of lymphadenectomy, which is a surgical procedure to remove one or more LNs in order to evaluate them for the presence of cancer. Several works for automated LN detection and segmentation have been proposed. However, there are a lot of false positives (FPs). The proposed method consists of LN candidate segmentation and FP reduction. LN candidates are extracted using RST analysis in each voxel of CT scan. RST analysis can discriminate between difference local intensity structures without influence of surrounding structures. In FP reduction process, we eliminate FPs using support vector machine with shape and intensity information of the LN candidates. The experimental result reveals that the sensitivity of the proposed method was 82.0 % with 21.6 FPs/case.