MR-Based Electrical Conductivity Imaging of Liver Fibrosis in an Experimental Rat Model.

BACKGROUND: Liver fibrosis is characterized by the excessive accumulation of extracellular matrix proteins. Electrical conductivity imaging at low frequency can provide novel contrast because the contrast mechanisms originate from the changes in the concentration and mobility of ions in the extracellular space. PURPOSE: To evaluate the feasibility of an MR-based electrical conductivity imaging that can detect the changes in a tissue condition associated with the progression of liver fibrosis. STUDY TYPE: Prospective phantom and animal study. ANIMAL MODEL: Fibrosis was induced by weekly intraperitoneal injection of dimethylnitrosamine (DMN) in 45 male Sprague-Dawley rats. FIELD STRENGTH/SEQUENCE: 3T MRI with a multispin-echo pulse sequence. ASSESSMENT: The percentage change of conductivity (Δσ, %) in the same region-of-interest (ROI) was calculated from the DMN-treated rats based on the values of the normal control rats. The percentage change was also calculated between the ROIs in each DMN-treated group. STATISTICAL TESTS: One-way analysis of variance (ANOVA) and a two-sample t-test were performed. RESULTS: Liver tissues in normal control rats showed a uniform conductivity distribution of 56.6 ± 4.4 (mS/m). In rats more than 5 weeks after induction, the fibrous region showed an increased conductivity of ≥12% compared to that of the corresponding normal control rats. From regional comparisons in the same liver, the fibrous region showed an increased conductivity of ≥11% compared to the opposite, less induced region of rats more than 5 weeks after induction. Liver samples from the fibrous region represent tissue damages such as diffuse centrilobular congestion with marked dilatation of central veins from the histological findings. Immunohistochemistry revealed significant levels of attenuated fibrosis and increased inflammatory response. DATA CONCLUSION: The increased conductivity in the fibrous region is related to the changes of the extracellular space. The correlation between the collagen deposition and conductivity changes is essential for future clinical studies. Level of Evidence 2 Technical Efficacy Stage 2 J. MAGN. RESON. IMAGING 2021;53:554-563.

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.

Multidetector CT findings differ between surgical grades of pancreatic fistula after pancreaticoduodenectomy.

OBJECTIVES: To define and correlate multidetector CT (MDCT) findings of pancreatic fistula after pancreaticoduodenectomy with surgical grading based on the 2016 Revised International Study Group of Pancreatic Fistula (ISGPF) classification. METHODS: Between May 2011 and December 2016, 235 patients with periampullary tumor underwent pancreaticoduodenectomy and postoperative MDCT. Patients were classified into three groups (clinically no pancreatic fistula (cNo-PF), grade B, and grade C) according to the ISGPF classification. MDCT images were retrospectively evaluated by two radiologists in consensus for the presence of pancreaticojejunostomy (PJ) dehiscence, PJ dehiscence diameter, PJ defect, acute necrotic collection (ANC), peripancreatic fluid collection, and imaging findings of complications. Categorical MDCT findings were compared among the three groups using Pearson's chi-square test, and PJ dehiscence diameter was compared using the Kruskal-Wallis test. RESULTS: There was no significant difference in patient demographics among the groups (cNo-PF = 133, grade B = 68, and grade C = 34), but the MDCT findings were significantly different regarding the presence of PJ dehiscence (p < 0.001), PJ defect (p < 0.001), ANC (p = 0.002), and imaging findings of total complications (p < 0.001). The diameters of PJ dehiscence were significantly different among the groups (cNo-PF [0.42 ± 1.54 mm], grade B [1.47 ± 2.33 mm], and grade C [5.38 ± 6.45 mm]) (p < 0.001). CONCLUSION: With respect to the presence of PF, postoperative MDCT findings may differ between surgical grading based on the ISGPF classification. KEY POINTS: • Regarding the presence of pancreatic fistula, the postoperative multidetector CT findings correlate well with surgical grading based on the International Study Group of Pancreatic Fistula classification. • Multidetector CT may provide reliable information to suggest pancreatic fistula after pancreaticoduodenectomy.

Conventional Chemoembolization Plus Radiofrequency Ablation versus Surgical Resection for Single, Medium-Sized Hepatocellular Carcinoma: Propensity-Score Matching Analysis.

PURPOSE: To retrospectively compare long-term outcomes of conventional chemoembolization plus radiofrequency (RF) ablation vs those of surgical resection in patients with a single 3-5-cm hepatocellular carcinoma (HCC). MATERIALS AND METHODS: From January 2008 to December 2017, 139 of 623 patients who underwent surgical resection and 60 of 186 patients who underwent chemoembolization/RF ablation in a single center were compared with respect to local tumor progression (LTP), intrahepatic distant recurrence (IDR), disease-free survival (DFS), overall survival (OS), major complications, and hospital stay before and after propensity-score matching. RESULTS: Mean follow-up periods were similar in the chemoembolization/RF ablation and surgical resection groups (41.9 mo vs 48.4 mo). Three (5%) and 17 (28.3%) patients in the chemoembolization/RF ablation group and 12 (8.6%) and 57 (41.0%) patients in the surgical resection group showed LTP and IDR (P = .366 and P =.114, respectively). At 1, 3, and 5 years, respective DFS rates were 88.1%, 65.3%, and 49.0% for chemoembolization/RF ablation and 84.2%, 58.2%, and 46.5% for surgical resection (P = .294). Moreover, respective OS rates were 95.0%, 73.5%, and 54.0% for chemoembolization/RF ablation and 97.1%, 87.4%, and 75.0% for surgical resection (P = .055). After matching (n = 52), therapeutic outcomes remained similar (P = .370, P = .110, P = .230, and P = .760, respectively). Surgical resection was associated with higher complication rates (P = .015) and longer hospital stays (8.4 d ± 3.7 vs 16.9 d ± 7.0; P < .001). CONCLUSIONS: Conventional chemoembolization combined with RF ablation may be feasible for single 3-5-cm HCCs, with comparable therapeutic outcomes vs surgical resection and shorter hospital stays.

Combined Therapy with Transarterial Chemoembolization and Radiofrequency Ablation for Hepatocellular Carcinoma: Does the Degree of Ethiodized Oil Accumulation within the Tumor Affect the Therapeutic Efficacy?

PURPOSE: To evaluate the effects of the degree of ethiodized oil accumulation achieved by transarterial chemoembolization followed by radiofrequency (RF) ablation on the treatment efficacy for a single intermediate-sized hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A total of 153 consecutive patients who underwent chemoembolization and RF ablation for a single intermediate-sized HCC (2-5 cm) were included. On the basis of the degree of ethiodized oil accumulation in HCC on cone-beam CT images, patients who underwent chemoembolization and RF ablation were classified into 2 groups: compact accumulation (≥ 75%) and noncompact accumulation (< 75%). The rates of cumulative local tumor progression (LTP), disease-free survival (DFS), and overall survival (OS) were compared between groups. RESULTS: Of the 153 patients, 89 were classified into the compact ethiodized oil accumulation group and 64 in the noncompact ethiodized oil accumulation group. There were no significant differences in patient demographic or HCC characteristics between groups except for the incidence of liver cirrhosis (P = .038) and the tumor margin morphology (P = .008). The cumulative LTP rate was significantly lower in the compact accumulation group than in the noncompact accumulation group (P = .013). There were no significant differences in the incidences of complications, DFS rates (P = .055), or OS rates (P = .184). CONCLUSIONS: The degree of ethiodized oil accumulation does not play a role in decreasing the OS or DFS rate after chemoembolization and RF ablation for intermediate-sized HCC; however, it may contribute to reducing the rate of LTP.

Electrical conductivity-based contrast imaging for characterizing prostatic tissues: in vivo animal feasibility study.

BACKGROUND: Electrical conductivity-based magnetic resonance (MR) imaging may provide unique information on tissue condition because its contrast originates from the concentration and mobility of ions in the cellular space. We imaged the conductivity of normal canine prostate in vivo and evaluated tissue contrast in terms of both the conductivity distribution and anatomical significance. METHODS: Five healthy laboratory beagles were used. After clipping the pelvis hair, we attached electrodes and placed each dog inside the bore of an MRI scanner. During MR scanning, we injected imaging currents into two mutually orthogonal directions between two pairs of electrodes. A multi spin echo pulse sequence was used to obtain the MR magnitude and magnetic flux density images. The projected current density algorithm was used to reconstruct the conductivity image. RESULTS: Conductivity images showed unique contrast depending on the prostatic tissues. From the conductivity distribution, conductivity was highest in the center area and lower in the order of the middle and outer areas of prostatic tissues. The middle and outer areas were, respectively, 11.2 and 25.5% lower than the center area. Considering anatomical significance, conductivity was highest in the central zone and lower in the order of the transitional and peripheral zones in all prostates. The transitional and peripheral zones were, respectively, 7.5 and 17.8% lower than the central zone. CONCLUSIONS: Current conductivity-based MR imaging can differentiate prostatic tissues without using any contrast media or additional MR scans. The electrical conductivity images with unique contrast to tissue condition can provide a prior information on tissues in situ to be used for human imaging.

Combined Therapy of Transcatheter Arterial Chemoembolization and Radiofrequency Ablation versus Surgical Resection for Single 2-3 cm Hepatocellular Carcinoma: A Propensity-Score Matching Analysis.

PURPOSE: To compare therapeutic outcomes of radiofrequency (RF) ablation combined with transcatheter arterial chemoembolization vs surgical resection (SR) for single 2-3 cm hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Seventy patients underwent combined chemoembolization/RF ablation therapy and 84 underwent SR. Local tumor progression (LTP), intrahepatic distant recurrence (IDR), disease-free survival (DFS), and overall survival (OS) rates, as well as major complications and duration of hospital stay, were compared between groups before and after propensity-score matching. RESULTS: LTP and IDR had developed in 9 (12.9%) and 24 (34.3%) patients in the combined treatment group and in 7 (8.3%) and 24 (28.6%) patients in the SR group (P = .262 and P = .252, respectively). The 1-, 3-, 4-, and 5-year DFS rates were similar between groups (82.6%, 53.2%, 53.2%, and 37.6%, respectively, vs 84.5%, 63.6%, 59.2%, and 52.1%, respectively; P = .278), and 1-, 3-, 4-, and 5-year OS rates were also comparable (94.2%, 81.2%, 74.1%, and 59.4%, respectively, vs 95.2%, 86.3%, 84.0%, and 80.3%, respectively; P = .081). After matching (n = 98), LTP, IDR, DFS, and OS rates were still similar (P = .725, P = .826, P = .484, and P = .578, respectively). Major complication rate was not significantly different (2.9% vs. 6.0%; P = .596); however, after matching, major complication rate was higher in SR group (2.0% vs. 6.1%; P < .001). Hospital stays were significantly longer in the SR group (16.6 ± 6.7 d vs 8.5 ± 4.1 d; P < .001). CONCLUSIONS: Before and after matching, there were no significant differences in long-term therapeutic outcomes between combined chemoembolization/RF ablation and SR groups. Therefore, combined chemoembolization/RF ablation therapy may be an alternative treatment for single 2-3 cm HCCs.

Volumetric analysis and indocyanine green retention rate at 15 min as predictors of post-hepatectomy liver failure.

OBJECTIVES: The actual future liver remnant (aFLR) is calculated as the ratio of remnant liver volume (RLV) to total functional liver volume (TFLV). The standardized future liver remnant (sFLR) is calculated as the ratio of RLV to standard liver volume (SLV). The aims of this study were to compare the aFLR with the sFLR and to determine criteria for safe hepatectomy using computed tomography volumetry and indocyanine green retention rate at 15 min (ICG R15). METHODS: Medical records and volumetric measurements were obtained retrospectively for 81 patients who underwent right hemi-hepatectomy for malignant hepatic tumours from January 2010 to November 2013. The sFLR was compared with the aFLR, and a ratio of sFLR to ICG R15 as a predictor of postoperative hepatic function was established. RESULTS: In patients without cirrhosis, the sFLR showed a stronger correlation with the total serum bilirubin level than the aFLR (R(2) = 0.499 versus R(2) = 0.239). Post-hepatectomy liver failure developed only in the group with an sFLR of <25%, regardless of ICG R15. In patients with cirrhosis, the aFLR and sFLR had no correlation with postoperative total serum bilirubin. An sFLR : ICG R15 ratio of >1.9 showed 66.7% sensitivity and 100% specificity. CONCLUSIONS: Regardless of ICG R15, an sFLR of ≥ 25% in patients without cirrhosis, and an sFLR of ≥ 25% with an sFLR : ICG R15 ratio of >1.9 in patients with cirrhosis indicate acceptable levels of safety in major hepatectomy.

Prognostic factors for survival after curative resection of distal cholangiocarcinoma: perineural invasion and lymphovascular invasion.

PURPOSE: The purpose of this study was to elucidate the prognostic factors for distal cholangiocarcinoma after curative resection, and to assess the significance of perineural invasion (PNI) and lymphovascular invasion (LVI) as prognostic factors. METHODS: A retrospective analysis of 91 patients who underwent radical surgery for distal cholangiocarcinoma between March 2004 and October 2011 was performed. We analyzed the survival rate and prognostic factors affecting the survival. RESULTS: The overall 1-, 3- and 5-year survival rates were 84.1, 49.7 and 38.9 %, respectively. In the univariate analysis, the prognostic factors influencing the survival were the histological differentiation, lymph node (LN) involvement and TNM stage. In the multivariate analysis, LN metastasis was the only independent prognostic factor. Although patients with PNI tended to show poorer survival, it was not a statistically significant factor (3- and 5-year OS; 62.0 and 54.6 % vs. 42.8 and 30.9 %, P = 0.166). In the patients with a total lymph node count (TLNC) of 11 or less, PNI was a significant prognostic factor; however, it was not a significant factor in the patients with a TLNC over 11. Overall, the LVI had no influence on the patient survival. CONCLUSIONS: LN metastasis was the only significant prognostic factor after the curative resection of distal cholangiocarcinoma. In cases where adequate dissection was performed, it appeared that the PNI and LVI had no influence on the survival.

Differential diagnosis of thyroid nodules using heterogeneity quantification software on ultrasound images: correlation with the Bethesda system and surgical pathology.

Ultrasonography (US)-guided fine-needle aspiration cytology (FNAC) is the primary modality for evaluating thyroid nodules. However, in cases of atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS), supplemental tests are necessary for a definitive diagnosis. Accordingly, we aimed to develop a non-invasive quantification software using the heterogeneity scores of thyroid nodules. This cross-sectional study retrospectively enrolled 188 patients who were categorized into four groups according to their diagnostic classification in the Bethesda system and surgical pathology [II-benign (B) (n = 24); III-B (n = 52); III-malignant (M) (n = 54); V/VI-M (n = 58)]. Heterogeneity scores were derived using an image pixel-based heterogeneity index, utilized as a coefficient of variation (CV) value, and analyzed across all US images. Differences in heterogeneity scores were compared using one-way analysis of variance with Tukey's test. Diagnostic accuracy was determined by calculating the area under the receiver operating characteristic (AUROC) curve. The results of this study indicated significant differences in mean heterogeneity scores between benign and malignant thyroid nodules, except in the comparison between III-M and V/VI-M nodules. Among malignant nodules, the Bethesda classification was not observed to be associated with mean heterogeneity scores. Moreover, there was a positive correlation between heterogeneity scores and the combined diagnostic category, which was based on the Bethesda system and surgical cytology grades (R = 0.639, p < 0.001). AUROC for heterogeneity scores showed the highest diagnostic performance (0.818; cut-off: 30.22% CV value) for differentiating the benign group (normal/II-B/III-B) from the malignant group (III-M/V&VI-M), with a diagnostic accuracy of 72.5% (161/122). Quantitative heterogeneity measurement of US images is a valuable non-invasive diagnostic tool for predicting the likelihood of malignancy in thyroid nodules, including AUS or FLUS.

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.

Sclerosing angiomatoid nodular transformation of the spleen related to IgG4-associated disease: report of a case.

Sclerosing angiomatoid nodular transformation (SANT) of the spleen is a rare benign vascular mass, with fewer than 100 cases documented. It is generally recognized as a vascular lesion that develops in the red pulp of the spleen; however, its pathogenesis is not clearly defined. We report a case of SANT of the spleen, which presents evidence to support the hypothesis that this disease entity is associated with IgG4-associated disease. Microscopically, the tumor was composed of multiple vascular structures separated by fibrous connective tissue and immunohistochemical examination revealed positive staining for CD31, CD34, factor VIII, and IgG4. Further research based on large number of cases is warranted to clarify the pathogenesis of this tumor.

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.

Pancreatic metastasis from papillary thyroid cancer: a case report and literature review.

Pancreatic metastasis from papillary thyroid cancer (PTC) is extremely rare; only 18 cases have been reported in the literature. However, several reviews have highlighted similar characteristics between metastatic and primary pancreatic tumors. The patient was a 51-year-old male with a history of total thyroidectomy, modified radical neck dissection, and radioactive iodine ablation for PTC in 2014. Nodules suspected of metastasis were found in both lungs on chest computed tomography (CT). However, after 6 months, a follow-up chest CT showed no increase in size; thus, a follow-up observation was planned. Six years after his initial diagnosis, abdominal CT and pancreas magnetic resonance imaging revealed a 4.7 cm cystic mass with a 2.5 cm enhancing mural nodule in the pancreas tail. We diagnosed the pancreatic lesion as either metastatic cancer or primary pancreas cancer. The patient underwent distal pancreato-splenectomy. After surgery, the pathological report revealed that the mass was metastatic PTC. Pancreatic metastasis from PTC indicates an advanced tumor stage and poor prognosis. However, pancreatectomy can increase the survival rate when the lesion is completely resectable. Therefore, surgical resection should be considered as a treatment for pancreatic metastasis from PTC.

Carcinosarcoma of the gallbladder: report of two cases.

Adenocarcinoma is the predominant histological type of carcinoma of the gallbladder, accounting for more than 80% of all gallbladder carcinomas. In contrast, carcinosarcoma of the gallbladder is an extremely atypical subset of gallbladder malignancies. It is characterized by the presence of both epithelial and mesenchymal components. Currently, fewer than 100 cases have been reported in the English literature. Therefore, knowledge and experience regarding this disease are limited. Recently, we experienced two cases of gallbladder carcinosarcoma, which were diagnosed as gallbladder carcinoma based on the preoperative clinical and radiological examinations. Cholecystectomies were performed in both cases, and the malignant tumor cells included carcinomatous and sarcomatous components histologically. The final pathological diagnoses were carcinosarcoma of the gallbladder. We herein report these two cases of gallbladder carcinosarcoma and review the previous pertinent literature.

Primary extragastrointestinal stromal tumor arising in the pancreas: report of a case.

Primary extragastrointestinal stromal tumors (EGISTs) arising in the pancreas are extremely rare, with only ten cases documented to our knowledge. We report a further case of EGIST of the pancreas. The patient was a 55-year-old man who presented with postprandial abdominal discomfort. Abdominal computed tomography and magnetic resonance imaging showed a lobulated heterogenous enhancing mass, 11 cm in diameter, in the abdominal cavity. No regional lymphadenopathy, ascites, or metastasis was seen radiologically. There was no obvious lesion in the stomach or small intestine. The initial diagnosis was a solid pseudopapillary tumor or serous cystic neoplasm. The patient underwent distal pancreatectomy with splenectomy. Microscopically, the tumor consisted of spindle cells arranged in short fascicles. Mitotic figures were seen in 7/50 high-power fields. Immunohistochemical examination revealed strongly positive staining for CD117. Based on these findings, the final pathologic diagnosis was a primary EGIST of the pancreas. This case consolidates the possibility that this rare tumor can involve the pancreas as a primary site and should be included in the differential diagnosis of cystic lesions in this site.

The prognostic value of the lymph node ratio in patients with distal cholangiocarcinoma after curative intended surgery: A single-center retrospective study.

Backgrounds/Aims: The goal of the present study was to evaluate the prognostic value of lymph node ratio (LNR) in distal cholangiocarcinoma (DCC) after curative intended surgery. Methods: Clinicopathological data of 162 DCC patients who underwent radical intended surgery between 2012 and 2020 were analyzed retrospectively. Prognostic factors related to overall survival (OS) and disease-free survival (DFS) were evaluated. Results: Median OS time and DFS time were 41 and 29 months, and 5-year OS rate and DFS rate were 44.7% and 38.1%, respectively. In the univariate analysis, significant prognostic factors for OS were histologic differentiation, American Joint Committee on Cancer (AJCC) stage, positive lymph node count, LNR, R1 resection, and perineural invasion. Preoperative carcinoembryonic antigen, carbohydrate antigen 19-9, infiltrative type, histologic differentiation, AJCC stage, positive lymph node count, LNR, R1 resection, perineural invasion, and lymph-vascular invasion were significant prognostic factors for DFS in the univariate analysis. In the multivariate analysis, histologic differentiation, R1 resection, and LNR were the independent prognostic factors for both OS and DFS. The LNR ≥ 0.2 group had a significantly poor prognosis in terms of OS (hazard ratio, 3.915; p = 0.002) and DFS (hazard ratio, 5.840; p < 0.001). Conclusions: LNR has significant value as a prognostic factor of DCC related to OS and DFS. LNR has the potential to be used as a modified staging system with furthermore studies.

Effects of Irradiation on Brain Tumors Using MR-Based Electrical Conductivity Imaging.

Ionizing radiation delivers sufficient energy inside the human body to create ions, which kills cancerous tissues either by damaging the DNA directly or by creating charged particles that can damage the DNA. Recent magnetic resonance (MR)-based conductivity imaging shows higher sensitivity than other MR techniques for evaluating the responses of normal tissues immediately after irradiation. However, it is still necessary to verify the responses of cancer tissues to irradiation by conductivity imaging for it to become a reliable tool in evaluating therapeutic effects in clinical practice. In this study, we applied MR-based conductivity imaging to mouse brain tumors to evaluate the responses in irradiated and non-irradiated tissues during the peri-irradiation period. Absolute conductivities of brain tissues were measured to quantify the irradiation effects, and the percentage changes were determined to estimate the degree of response. The conductivity of brain tissues with irradiation was higher than that without irradiation for all tissue types. The percentage changes of tumor tissues with irradiation were clearly different than those without irradiation. The measured conductivity and percentage changes between tumor rims and cores to irradiation were clearly distinguished. The contrast of the conductivity images following irradiation may reflect the response to the changes in cellularity and the amounts of electrolytes in tumor tissues.

Clinical features and surgical outcome of solid pseudopapillary tumor of the pancreas: 30 consecutive clinical cases.

BACKGROUND/AIM: This study examined the clinical characteristics and surgical outcomes of solid pseudopapillary tumors of the pancreas (SPT). METHODOLOGY: Cases of SPT encountered in our hospital between January 1994 and December 2009 were reviewed retrospectively. The clinicopathological factors in the benign and malignant cases were compared to determine what features of the tumor could suggest malignant potential. RESULTS: Thirty patients with SPT were identified: 26 females and 4 males with a average age of 30.5 years (range 9-66). The median size of the tumors was 6.2cm (range 1.25 to 15.0). Tumors were located in the head (50%), neck (3.3%), body (16.7%) and tail (30%) of the pancreas. Surgical procedures included a local tumor resection (10 cases) or radical resection, such as a pancreaticoduodenectomy (6 cases), central pancreatectomy (1 case) or distal pancreatectomy (13 cases). There was no recurrence after the surgical resection. All patients were alive at a median follow-up of 58 months (range 6 to 187). Among the clinico-pathological factors, the presence of calcification was associated with the malignant potential (OR=16.000, 95% CI=1.451-176.451, p=0.024). CONCLUSIONS: SPT is a less aggressive pancreatic neoplasm that differs from other pancreatic cancers. The prognosis is favorable after a surgical resection. The presence of calcification is a predictive factor for a malignant SPT.