Kiyohisa Kamimura

Pancreatic Adenocarcinoma: Variability of Diffusion-weighted MR Imaging Findings

PURPOSE To compare the apparent diffusion coefficients (ADCs) of pancreatic adenocarcinomas that appear hyperintense with clearly defined borders (clear hyperintense) with those that do not show clear hyperintense borders on diffusion-weighted magnetic resonance (MR) images. MATERIALS AND METHODS Institutional review board approval was obtained and informed consent was waived. Eighty patients with histologically confirmed pancreatic adenocarcinoma (mean tumor size, 32 mm) underwent fat-suppressed single-shot echo-planar 3.0-T diffusion-weighted MR imaging with diffusion gradients (b = 1000 sec/mm(2)). ADC values of the pancreatic adenocarcinomas (n = 80) and proximal (n = 51) and distal (n = 70) pancreas were compared by using the Friedman test, followed by the Wilcoxon signed-rank test, and the difference in serum amylase levels between pancreatic adenocarcinomas with and without clear hyperintensity was evaluated by using the x(2) test. RESULTS In 38 of 80 patients, pancreatic adenocarcinomas showed clear hyperintensity relative to the surrounding pancreas; 26 were hyperintense with unclear distal borders; 12, isointense; and four, hypointense. In all patients, the mean ADC (± standard deviation) of the tumors (1.16 × 10(-3) mm(2)/sec ± 0.22) was significantly lower than those of the proximal pancreas (1.33 × 10(-3) mm(2)/sec ± 0.16, P < .001) and the distal pancreatic parenchyma (1.24 × 10(-3) mm(2)/sec ± 0.23, P = .004). No significant difference in ADC was seen between the pancreatic adenocarcinomas without clear hyperintensity and the distal pancreas. The frequency of serum amylase levels greater than 120 U/L (2.00 μkat/L) was significantly higher than in those with clear hyperintense pancreatic adenocarcinomas (P < .001). CONCLUSION Diffusion-weighted MR imaging was not useful for delineating 47% of pancreatic adenocarcinomas, because of hyperintensity of the pancreatic parenchyma distal to the cancer.

Abnormal glucose metabolism in the anterior cingulate cortex in patients with schizophrenia

Changes in glucose metabolism were studied in the brains of schizophrenic patients treated with neuroleptics, using [(18)F]fluoro-deoxy-glucose positron emission tomography (FDG-PET). Fourteen male and eight female patients in their thirties and forties were studied in a resting state. Data from FDG-PET were processed with an anatomic standardization method, three-dimensional stereotactic surface projections (3D-SSP), which provided relative glucose metabolic values that mitigated the contamination of brain atrophy. Z-score maps indicating metabolic differences between the patient and control groups were also acquired. Metabolic values in 19 regions were evaluated in the right and left hemispheres. Patients showed decreased values in the frontal cortex, primary sensory regions and anterior cingulate cortex, more in the rostral affective subdivision than the dorsal cognitive subdivision in both hemispheres, and increased metabolic values in left and right basal ganglia, left temporal and right medial parietal regions. Values were more decreased in both anterior cingulate regions, and more increased in the right thalamus in male than female patients, suggesting gender-related dysfunction in the anterior cingulate and thalamus in schizophrenia. FDG-PET demonstrated that schizophrenia may be a disorder with a dysfunction of fronto-striatal-thalamic circuitry including the cingulate cortex.

Quantitative evaluation of liver function with T1 relaxation time index on Gd-EOB-DTPA-enhanced MRI: Comparison with signal intensity-based indices

To evaluate whether the reduction rate of T1 relaxation time of the liver (T1 relaxation time index) before and 20 minutes after gadolinium‐ethoxybenzyl‐diethylenetriaminepentaacetic acid (Gd‐EOB‐DTPA) injection has the potential to serve as an magnetic resonance imaging (MRI)‐based liver function test in comparison with signal intensity‐based indices.

Role of gastric distention with additional water in differentiating locally advanced gastric carcinomas from physiological uptake in the stomach on 18f-fluoro-2-deoxy-d-glucose Pet

PurposeIn this study, we investigated the role of gastric distention with additional water to determine whether it is beneficial for the differentiation of locally advanced gastric carcinomas from physiological 18F-fluoro-2-deoxy-D-glucose (FDG) uptake in the stomach and to characterize the FDG uptake of gastric carcinomas by relating it to the histopathological properties of the tumours. MethodsSixteen patients with locally advanced gastric carcinomas and 20 control patients were studied by FDG-PET. After whole-body PET imaging, the patients drank 400 ml of water and then spot imaging with additional water of the stomach was performed. The final diagnosis was determined from the results of surgery. The gastric areas were divided into the upper, middle, and lower parts. The degree of FDG uptake in the stomach was qualitatively evaluated by visual grading into three degrees. For quantitative analysis, the regional tumour uptake was measured by mean standardized uptake values using a region of interest technique. ResultsIn visual analysis, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PET without additional water ingestion were 100, 50, 62, 100 and 72%, respectively, and those of PET with additional water ingestion were 88, 100, 100, 91 and 94%, respectively. Using spot imaging under the condition with additional water ingestion, four gastric carcinomas were depicted more clearly. ConclusionGastric distention as a result of patients drinking a glass of water is a simple and noninvasive method for improving the diagnostic accuracy of FDG-PET in patients with locally advanced gastric carcinoma.

Contrast-enhanced CT and diffusion-weighted MR imaging: Performance as a prognostic factor in patients with pancreatic ductal adenocarcinoma

OBJECTIVE To determine whether contrast enhancement of CT and apparent diffusion coefficient on diffusion-weighted MR imaging are important parameters that can predict outcomes for patients with pancreatic ductal adenocarcinoma. MATERIALS AND METHODS Ninety-two patients with histologically confirmed pancreatic ductal adenocarcinoma who underwent quadriphasic CT (including unenhanced, pancreatic parenchymal, portal venous and delayed phases) and fat-suppressed single-shot echo-planar diffusion-weighted MR imaging at 3.0 T were retrospectively analyzed to investigate prognostic factors. Overall survival curves were drawn using the Kaplan-Meier method. Effects on survival of variables including age, sex, tumor location, tumor size, TNM stage, carbohydrate antigen 19-9, carcinoembryonic antigen, treatment, tumor contrast enhancement and apparent diffusion coefficient values were analyzed in univariate analysis using the log-rank test. Variables were analyzed in multivariate analyses using the Cox proportional hazards regression model. RESULTS Median survival for the entire patient population was 18.2 months. Higher contrast enhancement during all phases was associated with significantly longer overall survival (P<0.001 for all phases). The difference in overall survival between groups divided by median apparent diffusion coefficient value was not significant (P=0.672). TNM stage (P=0.026) and tumor contrast enhancement on CT (P=0.027) were significantly related to survival in multivariate analysis. CONCLUSIONS Poor enhancement of pancreatic adenocarcinomas on enhanced CT is associated with reduced patient survival.

Gd-EOB-DTPA-enhanced magnetic resonance imaging features of hepatic hemangioma compared with enhanced computed tomography.

AIM To clarify features of hepatic hemangiomas on gadolinium-ethoxybenzyl-diethylenetriaminpentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) compared with enhanced computed tomography (CT). METHODS Twenty-six patients with 61 hepatic hemangiomas who underwent both Gd-EOB-DTPA-enhanced MRI and enhanced CT were retrospectively reviewed. Hemangioma appearances (presence of peripheral nodular enhancement, central nodular enhancement, diffuse homogenous enhancement, and arterioportal shunt during the arterial phase, fill-in enhancement during the portal venous phase, and prolonged enhancement during the equilibrium phase) on Gd-EOB-DTPA-enhanced MRI and enhanced CT were evaluated. The degree of contrast enhancement at the enhancing portion within the hemangioma was visually assessed using a five-point scale during each phase. For quantitative analysis, the tumor-muscle signal intensity ratio (SIR), the liver-muscle SIR, and the attenuation value of the tumor and liver parenchyma were calculated. The McNemar test and the Wilcoxons signed rank test were used to assess the significance of differences in the appearances of hemangiomas and in the visual grade of tumor contrast enhancement between Gd-EOB-DTPA-enhanced MRI and enhanced CT. RESULTS There was no significant difference between Gd-EOB-DTPA-enhanced MRI and enhanced CT in the presence of peripheral nodular enhancement (85% vs 82%), central nodular enhancement (3% vs 3%), diffuse enhancement (11% vs 16%), or arterioportal shunt (23% vs 34%) during arterial phase, or fill-in enhancement (79% vs 80%) during portal venous phase. Prolonged enhancement during equilibrium phase was observed less frequently on Gd-EOB-DTPA-enhanced MRI than on enhanced CT (52% vs 100%, P < 0.001). On visual inspection, there was significantly less contrast enhancement of the enhancing portion on Gd-EOB-DTPA-enhanced MRI than on enhanced CT during the arterial (3.94 ± 0.98 vs 4.57 ± 0.64, respectively, P < 0.001), portal venous (3.72 ± 0.82 vs 4.36 ± 0.53, respectively, P < 0.001), and equilibrium phases (2.01 ± 0.95 vs 4.04 ± 0.51, respectively, P < 0.001). In the quantitative analysis, the tumor-muscle SIR and the liver-muscle SIR observed with Gd-EOB-DTPA-enhanced MRI were 0.80 ± 0.24 and 1.28 ± 0.33 precontrast, 1.92 ± 0.58 and 1.57 ± 0.55 during the arterial phase, 1.87 ± 0.44 and 1.73 ± 0.39 during the portal venous phase, 1.63 ± 0.41 and 1.78 ± 0.39 during the equilibrium phase, and 1.10 ± 0.43 and 1.92 ± 0.50 during the hepatobiliary phase, respectively. The attenuation values in the tumor and liver parenchyma observed with enhanced CT were 40.60 ± 8.78 and 53.78 ± 7.37 precontrast, 172.66 ± 73.89 and 92.76 ± 17.92 during the arterial phase, 152.76 ± 35.73 and 120.12 ± 18.02 during the portal venous phase, and 108.74 ± 18.70 and 89.04 ± 7.25 during the equilibrium phase, respectively. Hemangiomas demonstrated peak enhancement during the arterial phase, and both the SIR with Gd-EOB-DTPA-enhanced MRI and the attenuation value with enhanced CT decreased with time. The SIR of hemangiomas was lower than that of liver parenchyma during the equilibrium and hepatobiliary phases on Gd-EOB-DTPA-enhanced MRI. However, the attenuation of hemangiomas after contrast injection was higher than that of liver parenchyma during all phases of enhanced CT. CONCLUSION Prolonged enhancement during the equilibrium phase was observed less frequently on Gd-EOB-DTPA-enhanced MRI than enhanced CT, which may exacerbate differentiating between hemangiomas and malignant tumors.

Assessment of diastolic function using 16-frame 201Tl gated myocardial perfusion SPECT: a comparative study of QGS2 and pFAST2

ObjectiveThe objective of the present study is to investigate the correlations across various types of interface software for 201Tl gated myocardial perfusion SPECT (MPS) in calculating two common diastolic function parameters (DFx), peak-filling rates (PFR), and time-to-peak filling (TTPF).MethodsA total of 109 patients (66 men and 43 women; age 35–78 years) were studied. All patients were classi-fied into three groups (i.e., ND, no-defect group; SD, small-defect group; LD, large-defect group) to clarify the influence of perfusion defects possibly affecting the analysis. Two kinds of available software, namely, quantitative gated SPECT (QGS2) and perfusion and functional analysis for gated SPECT (pFAST2) with cardioGRAF were used to obtain PFR and TTPF. Finally, we analyzed the correlation between DFx obtained with the two different kinds of software.ResultsThe values of LVEF, PFR, and TTPF were assessed in all patients. In both the ND (correlation coefficients were 0.92, 0.79, and 0.99, respectively) and SD groups (correlation coefficients were 0.74, 0.88, and 0.98, respectively), a strong correlation was observed. In contrast, PFR did not show a significant correlation in the LD group.ConclusionsWith the two different kinds of software, QGS2 and pFAST2, the calculated PFR was almost equal and showed good correlations in both ND and SD groups. In contrast, the numerical value varied between the two methods, and its correlation was poor in the LD group. However, TTPF showed a good correlation regardless of the presence of perfusion defects, and the values were equal. TTPF was confirmed to be a stable diastolic index across the two kinds of software, QGS2 and pFAST2, in 201Tl gated MPS.

Histogram Analysis of Apparent Diffusion Coefficient in Differentiating Pancreatic Adenocarcinoma and Neuroendocrine Tumor.

AbstractThe aim of this study was to investigate whether histogram analysis in diffusion-weighted (DW) magnetic resonance imaging (MRI) can help differentiate pancreatic adenocarcinomas from neuroendocrine tumors.Sixty-four patients with histologically confirmed 53 pancreatic adenocarcinomas or 19 neuroendocrine tumors underwent DW MRI. We evaluated the pixel distribution histogram parameters (mean, skewness, kurtosis, and entropy) of the apparent diffusion coefficient (ADC) values derived from b-values of 0 and 200 (ADC200), 0 and 400 (ADC400), or 0 and 800 (ADC800) s/mm2. Histogram parameters were compared between pancreatic adenocarcinomas and neuroendocrine tumors, and the diagnostic performance was evaluated by using receiver operating characteristic (ROC) analysis.The mean ADC200 and ADC400 were significantly higher in neuroendocrine tumors than in pancreatic adenocarcinomas (P = 0.001 and P = 0.019, respectively). Pancreatic adenocarcinomas showed significantly higher skewness and kurtosis on ADC400 (P = 0.007 and P = 0.001, respectively) and ADC800 (P = 0.001 and P = 0.001, respectively). With all b-value combinations, the entropy of ADC values was significantly higher in pancreatic adenocarcinomas (P < 0.001 for ADC200; P = 0.001 for ADC400; P < 0.001 for ADC800), and showed the highest area under the ROC curve for diagnosing adenocarcinomas (0.77 for ADC200, 0.76 for ADC400, and 0.78 for ADC800).ADC histogram analysis of DW MRI can help differentiate pancreatic adenocarcinomas from neuroendocrine tumors.

Effect of percutaneous endoscopic gastrostomy on gastrointestinal motility: evaluation by gastric-emptying scintigraphy.

PurposeFirstly, to assess the effect of percutaneous endoscopic gastrostomy (PEG) tube placement on gastric emptying, gastrointestinal (GI) tract motility and the rate of gastroesophageal reflux (GER). Secondly, to confirm whether correlations exist between drug absorption behaviour and GI tract motility using the combination method of absorption function analysis with the motility study. MethodsSubjects comprised 11 patients with neurological dysphagia. Gastric-emptying scintigraphy was performed both before PEG via nasogastric tube feeding and after PEG placement. After fasting for more than 8 h, each patient was administered 111 MBq of 99mTc-labelled diethylenetriaminepentaacetic acid (DTPA) with a 100 ml liquid meal via a nutrition tube. Dynamic imaging was performed immediately after administration of a radiolabelled liquid meal for a 1 h period and static imaging was performed after 1, 2, 3 and 6 h. Gastric emptying half-time (T50) was calculated in each patient, and GER ratio and GI transit rate were also evaluated. Simultaneously, we administered 10 mg of famotidine in six of the 11 patients and measured serum concentrations of famotidine at 0, 1, 2, 3 and 6 h. Using the time–concentration curve of famotidine, the maximum concentration of famotidine (Cmax) and area under the curve of famotidine (AUCf) were calculated for each patient. ResultsIn seven of 11 patients, T50 changed after PEG placement, but not significantly. The GER ratio was significantly decreased and complicated pneumonia improved after PEG placement. GI transit rate for each GI segment was unchanged after PEG placement. Significant linear correlations were identified between T50 and both Cmax and AUCf. ConclusionGastric-emptying scintigraphy with 99mTc-DTPA was effective in the evaluation of GI transit before and after PEG, as well as in assessing GER. Motility and famotidine absorption were maintained after PEG placement. Significant linear correlations were found between T50 and both Cmax and AUCf. These findings suggest that drug absorption may have some relationship between T50. The result may be more reliable with a larger population.

CASE REPORT: Successful Balloon-Occluded Retrograde Transvenous Obliteration for Ruptured Gastric Fundal Varices in a Patient with Child–Pugh C Cirrhosis: Case Report and Literature Review

The rupture of gastroesophageal varices is one of the leading causes of death in cirrhotic patients. Once gastric fundal varices bleed, the mortality rate is particular very high. Surgical procedures such as Hassab’s devascularization and transection have a limitation in urgent treatment of ruptured gastric varices because of poor underlying hepatic reserves. Endoscopic sclerotherapy, transjugular intrahepatic portsystemic shunt, and percutaneous transhepatic obliteration for ruptured gastric fundal varices can achieve temporary hemostasis but have unsatisfactory results and many complications. Child–Pugh C patients with bleeding from gastric fundal varices, in particular, have a higher mortality rate compared with Child A or B patients. Balloon-occluded retrograde obliteration with ethanolamine oleate–iopamidol is a promising treatment for ruptured gastric fundal varices. A case of successful balloon-occluded retrograde transvenous obliteration and the follow-up management for ruptured gastric fundal varices in a patient with Child–Pugh C cirrhosis is reported, and the literature reviewed.