Gaku Ohira

Relation between Hepatic and Portal Veins in the Right Paramedian Sector: Proposal for Anatomical Reclassification of the Liver

Although a right liver graft without a middle hepatic vein resulted in potential venous congestion in the right paramedian sector, the details of the hepatic venous distribution in the right paramedian sector have not been established. In this study, the ramification patterns of the hepatic veins draining the right anterosuperior segment (S8) and the relation between the hepatic and portal veins were assessed using multislice computed tomography in 44 patients without lesions in the liver. All 52 drainage veins of the ventral area of S8 joined the middle hepatic vein, and all 48 drainage veins of the dorsal area joined the right hepatic vein. The hepatic vein crossing between the ventral and dorsal areas was observed in each patient examined. Therefore, we propose a reclassification wherein the right paramedian sector is divided into ventral and dorsal segments. This new classification may contribute to the development of new and safer surgical procedures, including more limited resection and right lobe adult living donor liver transplantation to avoid graft congestion.

Role of Perfusion CT in Assessing Tumor Blood Flow and Malignancy Level of Gastric Cancer

Background/Aims: Intratumoral hemodynamics or tumor perfusion is useful in understanding the pathological background of the cancer. A parameter for a non-invasive, preoperative assessment of tumor perfusion has yet to be developed. Methods: The study included 50 patients who underwent surgery for gastric cancer. Perfusion computed tomography (P-CT) was performed using a 16-row multidetector CT, and tumor blood flow (ml/min/100 g tissue) values were measured. We compared blood flow with histopathological characteristics and evaluated its correlation with microvessel density and tumor stromal density and calculated the ratio of vessels and stromal tissue. Results: There was a significant decrease in blood flow in advanced tumor depth, peritoneal dissemination and undifferentiated subtypes. Cases with Lauren’s diffuse type carcinoma were found to have decreased blood flow compared to the mixed or intestinal type. As for the stromal structure, despite the lack of correlation with microvessel density, blood flow significantly decreased with increased stromal density. Conclusions: Decreased blood flow value acquired from P-CT may reflect a progressive state of gastric cancer. The pathological background for this relation involves the tumor stroma. Tumor perfusion decreased as the stage and malignant character of the tumor advanced, and therefore P-CT could be a better strategy to estimate the malignancy level of cancer.

New prognostic factor influencing long-term survival of patients with advanced gallbladder carcinoma

BACKGROUND Although the safety of operations has generally improved in recent years, the mortality of extended operations for advanced gallbladder carcinoma (GBC) remains high, and the outcomes of patients with advanced GBC requiring major surgery are poor. In this study, a newly formulated original stage classification of advanced GBC was evaluated to clarify prognostic factors affecting long-term survival. METHODS A total of 149 patients with resected GBC infiltrating beyond the propria muscle layer were analyzed retrospectively. These patients were classified into F0 (n = 50), F1 (n = 38), F2 (n = 38), and F3 (n = 23) according to the number of positive histopathologic factors, consisting of direct invasion to the liver, invasion to the hepatoduodenal ligament, and lymph node metastasis. Overall survival rates were compared with the Union Internationale Contre le Cancer TNM classification (6th edition). RESULTS Overall 5-year survival rates of patients with F0, F1, F2, and F3 were 60%, 35%, 5%, and 0%, respectively. Significant differences were observed, except between F2 and F3. In 38 patients with F1, there were no significant differences between 13 patients with direct invasion to the liver, 4 patients with invasion to the hepatoduodenal ligament, and 21 patients with lymph node metastasis. Multivariate analysis revealed that F classification was the most important independent risk factor to predict survival. CONCLUSION Patients with advanced GBC are expected to survive long if only 1 of hepatic invasion, hepatoduodenal ligament invasion, or lymph node metastasis is positive.

Utility of arterial phase of dynamic CT for detection of intestinal ischemia associated with strangulation ileus

AIM To clarify the usefulness of arterial phase scans in contrast computed tomography (CT) imaging of strangulation ileus in order to make an early diagnosis. METHODS A comparative examination was carried out with respect to the CT value of the intestinal tract wall in each scanning phase, the CT value of the content in the intestinal tract, and the CT value of ascites fluid in the portal vein phase for a group in which ischemia was observed (Group I) and a group in which ischemia was not observed (Group N) based on the pathological findings or intra-surgical findings. Moreover, a comparative examination was carried out in Group I subjects for each scanning phase with respect to average differences in the CT values of the intestinal tract wall where ischemia was suspected and in the intestinal tract wall in non-ischemic areas. RESULTS There were 15 subjects in Group I and 30 subjects in Group N. The CT value of the intestinal tract wall was 41.8 ± 11.2 Hounsfield Unit (HU) in Group I and 69.6 ± 18.4 HU in Group N in the arterial phase, with the CT value of the ischemic bowel wall being significantly lower in Group I. In the portal vein phase, the CT value of the ischemic bowel wall was 60.6 ± 14.6 HU in Group I and 80.7 ± 17.7 HU in Group N, with the CT value of the ischemic bowel wall being significantly lower in Group I; however, no significant differences were observed in the equilibrium phase. The CT value of the solution in the intestine was 18.6 ± 9.5 HU in Group I and 10.4 ± 5.1 HU in Group N, being significantly higher in Group I. No significant differences were observed in the CT value of the accumulation of ascites fluid. The average difference in the CT values between the ischemic bowel wall and the non-ischemic bowel wall for each subject in Group I was 33.7 ± 20.1 HU in the arterial phase, being significantly larger compared to the other two phases. CONCLUSION This is a retrospective study using a small number of subjects; however, it suggests that there is a possibility that CT scanning in the arterial phase is useful for the early diagnosis of strangulation ileus.

Suture Granuloma With False-Positive Findings on FDG-PET/CT Resected via Laparoscopic Surgery

A 61-year-old woman who had undergone total hysterectomy 16 years previously exhibited a pelvic tumor on computed tomography (CT). F-18 fluorodeoxyglucose (FDG) combined positron emission tomography (PET)/CT imaging revealed a solitary small focus of increased FDG activity in the pelvis. A gastrointestinal stromal tumor originating in the small intestine or another type of tumor originating in the mesentery (desmoid, schwannoma, or foreign body granuloma) was suspected; therefore, laparoscopic resection was conducted. A white, hard tumor was found to originate from the mesentery of the sigmoid colon and adhered slightly to the small intestine. The tumor was resected with a negative margin, and the pathologic diagnosis was suture granuloma. The possibility of suture granuloma should be kept in mind in cases of tumors with positive PET findings and a history of surgery close to the lesion. However, it is difficult to preoperatively diagnose pelvic tumors using a biopsy. Therefore, considering the possibility of malignancy, it is necessary to achieve complete resection without exposing the tumor.

Computed tomography perfusion imaging as a potential imaging biomarker of colorectal cancer

Neovascularization was reported to arise early in the adenoma-carcinoma sequence in colorectal cancer (CRC), and the importance of angiogenesis in cancer progression has been established. Computed tomography (CT) perfusion (CTP) based on high temporal resolution CT images enables evaluation of hemodynamics of tissue in vivo by modeling tracer kinetics. CTP has been reported to characterize tumor angiogenesis, and to be a sensitive marker for predicting recurrence or survival in CRC. In this review, we will discuss the biomarker value of CTP in the management of CRC patients.

Heterogeneity of Glucose Metabolism in Esophageal Cancer Measured by Fractal Analysis of Fluorodeoxyglucose Positron Emission Tomography Image: Correlation between Metabolic Heterogeneity and Survival

Background: Intratumoral heterogeneity is a well-recognized characteristic feature of cancer. The purpose of this study is to assess the heterogeneity of the intratumoral glucose metabolism using fractal analysis, and evaluate its prognostic value in patients with esophageal squamous cell carcinoma (ESCC). Methods: 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) studies of 79 patients who received curative surgery were evaluated. FDG-PET images were analyzed using fractal analysis software, where differential box-counting method was employed to calculate the fractal dimension (FD) of the tumor lesion. Maximum standardized uptake value (SUVmax) and FD were compared with overall survival (OS). Results: The median SUVmax and FD of ESCCs in this cohort were 13.8 and 1.95, respectively. In univariate analysis performed using Coxs proportional hazard model, T stage and FD showed significant associations with OS (p = 0.04, p < 0.0001, respectively), while SUVmax did not (p = 0.1). In Kaplan-Meier analysis, the low FD tumor (<1.95) showed a significant association with favorable OS (p < 0.0001). In wthe multivariate analysis among TNM staging, serum tumor markers, FD, and SUVmax, the FD was identified as the only independent prognostic factor for OS (p = 0.0006; hazards ratio 0.251, 95% CI 0.104-0.562). Conclusion: Metabolic heterogeneity measured by fractal analysis can be a novel imaging biomarker for survival in patients with ESCC.

Preoperative hepatic CT perfusion as an early predictor for the recurrence of esophageal squamous cell carcinoma: Initial clinical results

Reports suggest that hepatic blood flow may have an association with cancer progression. The aim of the present study was to evaluate whether the hepatic blood flow measured by CT perfusion (CTP) may identify patients at high-risk for postoperative recurrence of esophageal squamous cell carcinoma (ESCC). Prior to surgery, hepatic CTP images were obtained using a 320-row area detector CT. The data were analyzed by a commercially available software based on the dual input maximum slope method, and arterial blood flow (AF, ml/min/100 ml tissue), portal blood flow (PF, ml/min/100 ml tissue) and perfusion index [PI (%) = AF/AF + PF × 100] were measured. These parameters were compared with the pathological stage and outcome of the ESCC patients. Forty-five patients with ESCC were eligible for this study. The median follow-up period was 17 months, and recurrences were observed in 9 patients (20%). The preoperative PI values of the 9 patients with recurrence were significantly higher than those of the 36 patients without recurrence (23.9 vs. 15.9, P=0.0022). Patients were categorized into the following two groups; high PI (>20) and low PI (<20). The recurrence-free survival of the low PI group was significantly better than that of the high PI group (P<0.0001). A multivariate analysis showed that a high PI was an independent risk factor for recurrence (odds ratio, 19.1; P=0.0369). Therefore, the preoperative PI of the liver may be a useful imaging biomarker for predicting the recurrence of patients with esophageal cancer.

Hemoperitoneum secondary to exophytic leiomyoma: Report of a case

We report herein the case of a 63-year-old male with hemoperitoneum secondary to exogastric leiomyoma. The patient had been receiving anticoagulation therapy for a cerebral embolism and complained of sudden, severe abdominal pain. A sonogram and computed tomography scan showed an exogastric mass and massive ascites. A peritoneal puncture proved the presence of an intraperitoneal hemorrhage. An emergency laparotomy revealed a pedunculated bleeding tumor, thus confirming the preoperative diagnosis of a ruptured exogastric tumor. A microscopic analysis of the excised tumor demonstrated gastric leiomyoma. Other authors have reported hemoperitoneum secondary to gastric myogenic tumors, but no cases of leiomyomas could be found in the literature.

Incidence and risk factor of outlet obstruction after construction of ileostomy

There are several reports on the usefulness of diverting ileostomy for decreasing the incidence of anastomotic leakage and the severity of pelvic peritonitis. However, a number of complications induced by ileostomy itself have also been reported, including a special condition induced by obstruction at the outlet of the stoma known as “outlet obstruction.” In this study, we examined the frequency and risk factors of this complication based on the data of ileostomy cases in our institution. Methods: One hundred and seven patients who received ileostomy creation at our department from January 2010 to December 2015 were included. The incidence of outlet obstruction and risk factors were analyzed. Results: Outlet obstruction occurred in 18 cases (16.8%). The incidence was significantly higher in total colectomy or proctocolectomy cases as well as in those with left side construction and laparoscopic surgery than in other patients in a univariate analysis. However, in a multivariate analysis, no risk factors were extracted. Conclusions: To determine the true cause of this disease, a prospective study with a large number of cases is needed. Since multiple terms are used for this condition, resulting in confusion, a consensus on the appropriate terms is also important.