Effect of visceral fat area on outcomes of laparoscopyassisted distal gastrectomy for gastric cancer: subgroup analysis by gender and parameters of obesity.

PURPOSE: The aim of this study was to investigate the impact of the visceral fat area (VFA) of patients with gastric cancer undergoing laparoscopic surgery on operative outcomes such as number of retrieved lymph nodes (LNs) and operative time. METHODS: We retrospectively reviewed the medical records and the CT scans of 597 patients with gastric cancer who underwent laparoscopy assisted distal gastrectomy (LADG) with partial omentectomy and LN dissection (>D1 plus beta). Patients were stratified by gender, VFA, and body mass index (BMI), and the clinicopathologic characteristics and operative outcomes were evaluated. Multiple linear regression analysis was used to assess the effects of VFA and BMI on the number of retrieved LNs and operative time in male and female patients. RESULTS: The mean number of retrieved LNs was significantly decreased for both male and female patients with high VFA. The operative time was significantly longer for both male and female patients with high VFA. The number of retrieved LNs had a statistically significant negative correlation with VFA in both men and women, but not with BMI. The operative time had a statistically significant positive correlation with VFA in men, whereas the operative time had a statistically significant positive correlation with BMI in women. CONCLUSION: The preoperative VFA of male patients with gastric cancer who undergo LADG may affect the number of retrieved LNs and operative time. VFA was more useful than BMI for predicting outcomes of LADG.

Usefulness of acoustic radiation force impulse elastography in the differential diagnosis of benign and malignant solid pancreatic lesions.

PURPOSE: The aim of this study was to evaluate the tissue stiffness of solid pancreatic lesions by using acoustic radiation force impulse (ARFI) elastography to differentiate benign from malignant pancreatic lesions. METHODS: ARFI elastography was performed in 26 patients who had 27 focal solid pancreatic lesions, including 8 benign lesions (mass-forming pancreatitis, 5; autoimmune pancreatitis, 3) and 19 malignant lesions (pancreatic adenocarcinoma, 16; metastasis from colorectal cancer, 2; malignant neuroendocrine tumor, 1). On the elastographic images of virtual touch tissue imaging (VTI), the echogenicity of the mass was categorized on a 5-grade scale. On the elastographic image of virtual touch tissue quantification (VTQ), the shear wave velocities (SWVs) of the lesion and surrounding parenchyma were measured. RESULTS: On the VTI images, the mean echogenicity score of the malignant lesions (3.7±1.0) was higher than that of the benign lesions (3.1±0.4; P=0.023). On the VTQ images, there were no statistical differences in the mean SWV between the benign (2.4±1.1 m/sec) and malignant (3.3±1.0 m/sec) lesions (P=0.101). However, the mean SWV difference values between the lesion and background parenchyma of the malignant lesions (1.5±0.8 m/sec) were higher than those of the benign lesions (0.4±0.3 m/sec; P=0.011). CONCLUSION: ARFI elastography can determine the relative stiffness between a lesion and the background pancreatic parenchyma using VTI and VTQ, which is helpful in the differentiation between benign and malignant solid pancreatic lesions.

Focal thickening at the fundus of the gallbladder: computed tomography differentiation of fundal type adenomyomatosis and localized chronic cholecystitis.

BACKGROUND/AIMS: The objective of our study was to identify useful computed tomography (CT) findings for differentiating fundal type adenomyomatosis from localized chronic cholecystitis involving the fundus of the gallbladder. METHODS: We retrospectively identified cases of 41 patients with pathologically proven adenomyomatosis (n=21) or chronic cholecystitis (n=20) who had fundal thickening of the gallbladder on preoperative abdominal CT. Analysis of the CT findings included evaluation of the thickness, contour, border, intralesional cystic area, adjacent gallbladder wall thickening, presence of inner layer enhancement, enhancement grade, enhancement pattern, and presence of stones. Statistical analyses were performed using the Mann-Whitney U test and Fisher exact test. RESULTS: Oval contour, inner layer enhancement and intralesional cystic area were more frequently noted in adenomyomatosis than in chronic cholecystitis (p<0.05 for each finding). Flat contour and adjacent gallbladder wall thickening were more frequently observed in chronic cholecystitis than in adenomyomatosis. No differences between adenomyomatosis and chronic cholecystitis in terms of the thickness, enhancement grade, enhancement pattern and presence of stones were apparent. CONCLUSIONS: CT may help to differentiate fundal type adenomyomatosis from localized chronic cholecystitis involving the fundus of the gallbladder.

Epididymal lymphoma: report of two cases and imaging findings.

Epididymal lymphoma is a very rare tumor that is difficult to differentiate radiologically from other paratesticular tumors. Most cases of epididymal lymphoma are secondary involvement of the epididymis in patients with testicular lymphoma. However, isolated epididymal lymphoma is very rare. We herein report two cases of isolated epididymal lymphoma with different imaging findings. Patient 1 was a 52-year-old man who presented with a painless scrotal mass. Patient 2 was a 65-year-old man who presented with painless scrotal swelling. Ultrasound (US) demonstrated different imaging findings: US in patient 1 showed a well-defined round mass in the tail of the epididymis with hypervascularity confined to the epididymis, while US in patient 2 showed diffuse infiltrative enlargement with hypervascularity confined to the epididymis. Orchiectomy performed in both patients revealed diffuse large B-cell lymphoma confined to the epididymis.

Application of 31P MR spectroscopy to the brain tumors.

OBJECTIVE: To evaluate the clinical feasibility and obtain useful parameters of (31)P magnetic resonance spectroscopy (MRS) study for making the differential diagnosis of brain tumors. MATERIALS AND METHODS: Twenty-eight patients with brain tumorous lesions (22 cases of brain tumor and 6 cases of abscess) and 11 normal volunteers were included. The patients were classified into the astrocytoma group, lymphoma group, metastasis group and the abscess group. We obtained the intracellular pH and the metabolite ratios of phosphomonoesters/phosophodiesters (PME/PDE), PME/inorganic phosphate (Pi), PDE/Pi, PME/adenosine triphosphate (ATP), PDE/ATP, PME/phosphocreatine (PCr), PDE/PCr, PCr/ATP, PCr/Pi, and ATP/Pi, and evaluated the statistical significances. RESULTS: The brain tumors had a tendency of alkalization (pH = 7.28 ± 0.27, p = 0.090), especially the pH of the lymphoma was significantly increased (pH = 7.45 ± 0.32, p = 0.013). The brain tumor group showed increased PME/PDE ratio compared with that in the normal control group (p = 0.012). The ratios of PME/PDE, PDE/Pi, PME/PCr and PDE/PCr showed statistically significant differences between each brain lesion groups (p < 0.05). The astrocytoma showed an increased PME/PDE and PME/PCr ratio. The ratios of PDE/Pi, PME/PCr, and PDE/PCr in lymphoma group were lower than those in the control group and astrocytoma group. The metastasis group showed an increased PME/PDE ratio, compared with that in the normal control group. CONCLUSION: We have obtained the clinically applicable (31)P MRS, and the pH, PME/PDE, PDE/Pi, PME/PCr, and PDE/PCr ratios are helpful for differentiating among the different types of brain tumors.

US screening for detection of nonpalpable locoregional recurrence after mastectomy.

PURPOSE: To assess the value of screening ultrasonography (US) in the detection of nonpalpable locoregional recurrence following mastectomy for breast cancer and to describe the US appearances of occult recurrent cancers. MATERIALS AND METHODS: During a 36-month period, 1180 consecutive US screenings were performed for mastectomy sites and ipsilateral axillary fossae in 468 asymptomatic women who had undergone mastectomy for breast cancer. All US results were divided into three groups: negative findings, probably benign nodules, and suspicious for malignant nodules. The final diagnoses were based on pathology results and clinical or sonographic follow-up for more than 12 months. The diagnostic performance of US for detecting nonpalpable locoregional recurrence was assessed. The US appearances of occult recurrent cancers were retrospectively reviewed. RESULTS: Of the 468 patients assessed, 19 (4.1%) showed "suspicious for malignant nodules"; of these lesions, 10 were malignant. One false-negative case was identified. The sensitivity and specificity were 90.9% and 98.0%, respectively. A biopsy positive predictive value of 52.6% was observed. Cancer detection rates were 2.1% with US screenings of mastectomy sites and ipsilateral axillary fossae. The common US features of occult recurrences at the mastectomy sites were irregular shaped, not-circumscribed marginated, and hypoechoic masses with intratumoral vascularities. The most common location was within the deep muscle layer. CONCLUSION: Although locoregional recurrence infrequently occurs after mastectomy for breast cancer, screening US enables detection of nonpalpable cancer before it can be detected by clinical examination. Routine follow-up US can be advocated for early detection of nonpalpable locoregional recurrent cancer.

Triple rule-out acute chest pain evaluation using a 320-row-detector volume CT: a comparison of the wide-volume and helical modes.

The purpose of this study was to investigate the image quality and radiation dose of triple rule-out computed tomography (TROCT) using a 320-row-detector volume CT system to compare the wide-volume and helical modes of this CT system. Sixty-four patients with noncritical chest pain were allocated to one of 2 groups according to the type of CT examination mode used. Group 1 patients were examined using the wide-volume (non-spiral) mode and group 2 patients were examined using the 160-detector row helical mode, with the same contrast injection protocol in both methods [biphasic injection protocol; injection rate of 4 ml/s, median volume, 70 ml (range 65-100 ml)]. Attenuations of the pulmonary trunk, ascending aorta, and coronary arteries were measured in Hounsfield units; a subjective overall patient-based image quality score of 1-3 was awarded to each study. Effective doses, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Average effective dose was significantly lower in group 1 than group 2 (9.7 ± 5.1 vs. 16 ± 5.9 mSv, P < 0.001). The mean attenuation of the main pulmonary trunk was significantly higher in group 1 than group 2 (P = 0.04) and mean attenuations in other vessels were not significant different. SNR and CNR were not significantly different between the groups. The proportion of diagnostic image qualities for chest CT angiography (CTA) was similar between the groups (93.5 vs. 93.9 %). In coronary CTA, group 1 showed a higher proportion of diagnostic image qualities than group 2 (100 vs. 87.9 %). The use of wide-volume mode of 320-detector CT reduces the overall effective radiation dose and results in similar attenuation and image quality for TROCT as compared with the helical mode.

Acoustic radiation force impulse elastography for hepatocellular carcinoma-associated radiofrequency ablation.

AIM: To evaluate the potential usefulness of acoustic radiation force impulse (ARFI) images for evaluation of hepatocellular carcinomas (HCC)-associated radiofrequency ablation. METHODS: From January 2010 to June 2010, a total of 38 patients with HCC including recurred HCCs after RFA underwent ARFI elastography. The brightness of tumor was checked and the shear wave velocity was measured for the quantification of stiffness. According to the brightness, the tumors were classified as brighter, same color and darker compared with adjacent parenchyma. Using the same methods, 8 patients with recurred HCCs after RFA state were evaluated about the brightness compared with adjacent RFA ablation area. RESULTS: In the 38 patients with HCCs, 20 (52.6%) were brighter than surrounding cirrhotic parenchyma. Another 13 (34.2%) were darker. The others (5 cases, 13.2%) were seen as the same color as the adjacent liver parenchyma. Post-RFA lesions were darker than previous tumor and surrounding parenchyma in all 38 cases. However, recurred HCCs were brighter than the treated site in all 8 cases. CONCLUSION: Using ARFI technique is helpful for differential diagnosis in order to detect recurred HCCs more easily in patients with confusing status.

Actinomycosis of the appendix mimicking appendiceal tumor: a case report.

Actinomycosis is an uncommon chronic infectious disease. Common sites of involvement include the cervicofacial, thoracic and abdominopelvic regions. In abdominopelvic actinomycosis, the ileocecal region, including the appendix, is the most commonly involved site. In some reports, limited appendiceal actinomycosis has revealed a thickened appendiceal wall with peri-appendiceal inflammation as acute appendicitis or perforated appendicitis. We experienced pathologically confirmed intraluminal limited appendiceal actinomycosis without peri-appendiceal infiltration. Here, we report the computed tomography and ultrasound findings.

Radiofrequency ablation of renal VX2 tumors with and without renal artery occlusion in a rabbit model: feasibility, therapeutic efficacy, and safety.

The purpose of this study was to determine the therapeutic efficacy of radiofrequency ablation for treating renal VX2 tumors with and without renal artery occlusion in a rabbit model. Twenty-four New Zealand White rabbits were percutaneously implanted with renal VX2 tumors. Fifteen days after implantation, both kidneys were surgically exposed, and radiofrequency ablation was conducted. Group A (n=12) was treated with renal artery occlusion, and group B (n=12) was treated without occlusion. In each rabbit, the serum creatinine was measured to evaluate renal damage after arterial occlusion. Two days after radiofrequency ablation, computed tomography was performed to evaluate the difference in therapeutic results between the two groups. We also compared histopathologic findings after radiofrequency ablation. The mean tumor size was 2.4 cm (range, 1.2-3.1 cm). Radiofrequency ablation of renal tumors was technically feasible in all cases. Complete ablation was achieved in 11 of the 12 rabbits (92%) in group A but in only eight of the 12 rabbits (67%) in group B (P<0.05). The average time of radiofrequency application was shorter in group A (mean, 547 s) than in group B (mean, 826 s) (P<0.05). After radiofrequency ablation, the serum creatinine increased from 1.54 to 1.82 mg/dl in group A and from 1.46 to 1.78 mg/dl in group B. However, there was no significant difference between the two groups (P>0.05). In conclusion, radiofrequency ablation with renal artery occlusion can decrease the duration of treatment and increase the therapeutic efficacy for renal VX2 tumors.

Radiofrequency ablation treatment for renal cell carcinoma: early clinical experience.

OBJECTIVE: To evaluate the early clinical experience associated with radiofrequency (RF) ablation in patients with renal cell carcinoma (RCC). MATERIALS AND METHODS: The RF ablation treatment was performed on 17 tumors from 16 patients (mean age, 60.5 years; range, 43-73 years) with RCC. The treatment indications were localized, solid renal mass, comorbidities, high operation risk, and refusal to perform surgery. All tumors were treated by a percutaneous CT (n = 10), followed by an US-guided (n = 2), laparoscopy-assisted US (n = 2), and an open (n = 2) RF ablation. Furthermore, patients underwent a follow-up CT at one day, one week, one month, three and six months, and then every six months from the onset of treatment. We evaluated the technical success, technical effectiveness, ablation zone, benign periablation enhancement, irregular peripheral enhancement, and complications. RESULTS: All 17 exophytic tumors (mean size, 2.2 cm; range, 1.1-5.0 cm) were completely ablated. Technical success and effectiveness was achieved in all cases and the mean follow-up period was 23.8 months (range, 17-33 months). A local recurrence was not detected in any of the cases; however, five patients developed complications as a result of treatment, including hematuria (n = 2), mild thermal injury of the psoas muscle (n = 1), mild hydronephrosis (n = 1), and fistula formation (n = 1). CONCLUSION: The RF ablation is an alternative treatment for exophytic RCCs and represents a promising treatment for some patients with small RCCs.

Benign submucosal lesions of the stomach and duodenum: imaging characteristics with endoscopic and pathologic correlation.

Benign submucosal lesions of the stomach and duodenum are occasionally encountered during endoscopy. But endoscopy has its limitations in the diagnosis and differentiation of these lesions, because submucosal lesions are often difficult to visualize at endoscopy due to minimal change of the overlying mucosa. Furthermore, endoscopic biopsy may not always yield adequate tissue for diagnosis due to the submucosal location of the lesions. For this reason, the role of radiologic imaging is important in the diagnosis of submucosal lesions of the stomach and duodenum. Recent advances in computed tomography (CT) and sonographic technology are helpful in narrowing the differential diagnosis of gastroduodenal submucosal lesions. In contrast to endoscopy and barium studies, CT or ultrasonography (US) provides information about both the gastric wall and the extragastric extent of the disease. Arterial phase contrast enhanced CT enables us to discriminate a mass of submucosal from that of a mucosal origin in the differential diagnosis of gastric or duodenal lesions. Although endoscopic sonography has been considered the better modality in the diagnosis of gastroduodenal submucosal lesions, transabdominal sonography can still be an alternative method to endoscopic sonography in assessing of the origin and character of the submucosal lesions. Some gastroduodenal submucosal lesions have similar radiologic findings that make differentiation difficult. But despite overlaps in radiologic findings, some lesions have characteristic radiologic features that may suggest a specific diagnosis. Knowledge of the differential diagnosis of benign submucosal lesions in the stomach and duodenum may promote correct diagnosis and appropriate treatment.

[Prognostic factors for survival in patients with hepatocellular carcinoma after radiofrequency ablation].

BACKGROUND/AIMS: Currently there is no consensus on which staging system is the best in predicting the survival of patients with hepatocellular carcinoma (HCC). The aim of this study was to identify independent factors to predict survival and to compare 4 available prognostic staging systems in patients with early HCC after radiofrequency ablation. METHODS: We retrospectively studied 100 Korean patients with early HCC. Prognostic factors for survival were analysed by univariate and multivariate analysis using the Kaplan-Meier method and Cox proportional hazard regression models. Okuda, Cancer of the Liver Italian Program (CLIP), TNM and Japanese integrated staging score (JIS score) were evaluated before the treatments. RESULTS: Overall survival rates of 12, 24 and 36 months were 89%, 76%, and 64% respectively and the mean survival duration was 45 months. Multivariable analysis showed that albumin, total bilirubin and size of tumor were independent prognostic factors. Multivariate analysis showed that TNM and JIS score staging systems were significant staging systems for the prediction of prognosis. CONCLUSIONS: Both TNM and JIS score are more effective than the Okuda and CLIP staging systems in stratifying patients into different risk groups with early HCC. However, JIS score gives better prediction of prognosis in patients with HCC after radiofrequency ablation.

Extrapulmonary small-cell carcinoma of the liver.

A 53-year-old man was admitted to our hospital for the evaluation of a mass (13 x 10 cm) in the left lobe of the liver seen by imaging studies. On subsequent biopsy of the mass, the lesion was histologically diagnosed as malignant small round-cell tumor, consistent with metastatic small-cell carcinoma. Segment IV segmentectomy was performed. On pathological examination, the mass showed a yellowish-gray granular appearance with multifocal hemorrhage and necrosis. The phenotypes shown by immunohistochemistry revealed characteristic patterns of small-cell carcinoma (neuron-specific enolase [NSE]+, synaptophysin+, c-Kit+, cluster designation [CD]56+, epithelial membrane antigen [EMA]+, cytokeratin [CK]7-). High resolution-computed tomography (HRCT) revealed inactive pulmonary tuberculosis with small calcified tuberculoma in the right upper lobe. Sputum cytology was negative for malignancy. The postoperative course was uneventful, and platinum-based chemotherapy (cisplatin, etoposide) was initiated.

Perfusion imaging of the brain using Z-score and dynamic images obtained by subtracting images from before and after contrast injection.

OBJECTIVE: The aim of this study was to examine the feasibility of perfusion imaging of the brain using the Z-score and subtraction dynamic images obtained from susceptibility contrast MR images. MATERIALS AND METHODS: Five patients, each with a normal MRI, Moya-moya, a middle cerebral artery occlusion, post-trauma syndrome, and a metastatic brain tumor, were selected for a presentation. A susceptibility-contrast echo-planar image after a routine MRI was taken as the source image with a rapid manual injection of 0.1 mmol/kg of Gd-DTPA. The inflow and washout patterns were observed from the time-signal intensity curve of the serial scans using the standard program of an MRI machine. The repeated Z-score images of the peak and late phases were made using the threshold Z-score values between 1.4 and 2.0 in four to five studies of the pre-contrast, peak, and late phases. Dynamic subtraction images were produced by subtracting sequential post-contrast images from a pre-contrast image and coloring these images using a pseudocolor mapping method. RESULTS: In the diseases with perfusion abnormalities, the Z-score images revealed information about the degree of perfusion during the peak and late phases. However, the quality varied with the Z-score threshold and the studies selected in a group. The dynamic subtraction images were of sufficient quality with no background noise and more clearly illustrated the temporal changes in perfusion and delayed perfusion. CONCLUSION: The Z-scores and dynamic subtraction images illustrated the degree of perfusion and sequential changes in the pattern of perfusion, respectively. These images can be used as a new complimentary method for observing the perfusion patterns in brain diseases.

Ultrasonographic evidence of phenotypic instability during hepatocarcinogenesis in N-nitrosomorpholine-treated rats.

Carcinogen-induced hepatoma in immunocompetent animal models has shown a progress similar to the clinical course of human hepatoma. Ultrasonography (US) was used for consecutive evaluation of the phenotypic changes in Sprague-Dawley rats exposed for 8 weeks to N-nitrosomorpholine (NNM, 200 mg/L). Three distinctive US findings were ascites, coarseness (defined as small and heterogeneously widespread increased echogenecity), and nodularity (defined as a >0.6-cm-sized echogenic region and clearly showing a tumor-like mass). Abdominal ascites was observed in 5 of 26 rats at week 8 NNM posttreatment and the number of rats showing ascites gradually increased. Coarseness (22 of 26 rats) and nodularity (1 of 18) appeared at weeks 8 and 17 NNM posttreatment, respectively. The gross and histological findings indicated that coarseness and nodularity shown in US reflected fibrosis and hepatocellular carcinoma or cholangiofibroma, respectively. The computer-aided quantification of coarseness and nodularity showed that the regression-linked phenotypic instability was present in coarseness but not in nodularity. We conclude that the heterogeneity of preneoplasia in NNM-treated rats might be induced by phenotypic instability rather than random initiating events of preneoplastic lesion.