Recent imaging progresses were reviewed for the diagnosis of pancreatic disorders. The advent of the ultrasound contrast agents (Levovist^®and Sonazoid^®) enabled the combined diagnosis of plain B-mode images and contrast-enhanced images. This progress became applicable for endoscopic ultrasonography diagnosis with the electronic scanning method. Diffusion weighted imaging, which utilizes an image enhanced by the proton diffusion of a water molecule within cellular cytoplasm or extracellular fluid, and perfusion CT may be important to recognize the present status of diagnostic imaging.

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The usefulness of endoscopic ultrasonography(EUS) for diagnosing pancreatic disorders is widely recognized; on the other hand, the characteristic vascularity of each disorder is well known. Further improvement of the diagnostic accuracy using second-generation ultrasound contrast agents has recently been experienced. We investigated the usefulness of contrast-enhanced EUS(CE-EUS) for the differential diagnosis of pancreatic disorders. Patients with pancreatic ductal cancer(PC), autoimmune pancreatitis(AIP), mass-forming pancreatitis(MFP), and pancreatic endocrine tumor(PET) who underwent CE-EUS at our institute were analyzed retrospectively. The contrast agent, Sonazoid^® (Daiichi Sankyo, Tokyo, Japan), was injected intravenously. Time-intensity curve (TIC)-based quantitative evaluation of the pancreatic disorders and performance of EUS in combination with TIC was performed to diagnose benignancy or malignancy. The echo-intensity reduction rate at 1 minute was significantly greater in PC than AIP, MFP and PET. The CE-EUS with the dynamic quantitative analysis of TIC increased the diagnostic accuracy for pancreatic disorders.

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We have reported that CE-US coupled with hemodynamics is useful in the diagnosis of pancreatic diseases, in particular the differentiation between pancreatic mass and cystic lesions, like pancreatic cancer and mass-forming pancreatitis in mass lesions, and the evaluation of the level of cancer progression. However, in evaluating the hemodynamics that reflects tissue conditions, the use of the high MI contrast agent, Levovist^® has had limitations and therefore a precise evaluation was difficult. Thus, a new ultrasonography technique using the second generation low MI contrast agent, Sonazoid^® was developed. The aim of our study is to evaluate whether this new sonography technique will be able to be applied in pancreatic diseases, and to compare it with CE-US using the conventional contrast agent, Levovist^®.
The results of pancreatic diseases in which Sonazoid^® was used showed that on the whole, more detailed contrast images were obtained compared to Levovist^®. Moreover, contrast evaluations that were more precise, compared to previous methods, were possible. In addition, detailed movements of microbubbles in the capillaries that were difficult to visualize with Levovist^® could be visualized repeatedly in real-time with Sonazoid^®. The performance of CE-US in pancreatic diseases was greatly improved when Sonazoid^® was used compared to the conventional method using Levovist^®, and was therefore favorable in the differential diagnosis.

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Endoscopic ultrasonography(EUS) is superior to any other modality with respect to spatial resolution, and plays an important role in the detection of small pancreatic carcinomas, particularly those measuring 2cm or less. However, it is sometimes difficult to characterize a hypoechoic mass detected by conventional EUS. We developed a new EUS system that enabled the use of contrast harmonic imaging in the field of EUS. Contrast-enhanced harmonic EUS(CH-EUS) categorized solid pancreatic lesions into 4 vascular patterns: avascular, hypovascular, isovascular and hypervascular. The sensitivity and specificity in diagnosing pancreatic carcinomas as hypovascular masses by CH-EUS are 89-96% and 64-89%, respectively. In particular, CH-EUS is superior to MDCT in diagnosing small carcinomas (2cm or less). With respect to pancreatic cystic lesions, the use of contrast enhancement excludes avascular regions (mucous clots), resulting in a clear depiction of the mural nodule of intraductal papillary mucinous neoplasms.

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The clinical course of chronic pancreatitis(CP) leads to a high rate of morbidity and mortality over a 20- to 25-year period. Therefore, it is important to diagnose it at its early stage for optimal management. Endoscopic ultrasonography(EUS) provides excellent detail of the pancreatic parenchyma and duct which are not detectable by other standard imaging modalities such as CT scan, transabdominal ultrasound and ERCP, because of its ability to place the transducer in close proximity to the pancreas. Therefore, EUS can detect minimal changes in the pancreatic duct and parenchyma, and may reveal early CP. Several investigators have demonstrated the usefulness of EUS for the diagnosis of CP. However, the images obtained are operator-dependent and inter-observer variability limits the accuracy of EUS in CP. In spite of its limitations, EUS is the most sensitive imaging test for screening of CP. In 2009, EUS findings were included in the new criteria for CP diagnosis. Indeed, EUS could play a critical role in diagnosing early stage CP.

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Pancreatic cancer is a severe disease with a poor prognosis; therefore, early diagnosis is critically important. Progress of various imaging studies is remarkable and the number of small pancreatic cancers detected has been increasing because of the development of MDCT and MRI equipment as well as EUS and improved skills. 693 patients were clinically diagnosed with pancreatic cancer at our institution. 152 (22.2%) patients underwent surgical resection, 32 (4.6%) patients were histopathologically confirmed as TS1 pancreatic cancer. The rate of mass detection was 92.3% by MDCT, 77.8% by DWI, and 100% by EUS. The rate of accurate diagnosis was 84.6% by MDCT, 77.8% by EUS, and 96.8% by EUS. Comprehensive diagnosis by their combination enabled us to diagnose all those cases as pancreatic cancer. We consider that diagnosis of small pancreatic cancers is now feasible by utilizing MDCT, DWI, and EUS.

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The mode of extension of branch-duct intraductal papillary mucinous neoplasms of the pancreas(IPMN) and its diagnosis with endoscopic ultrasonography(EUS) and intraductal ultrasonography(IDUS) were reviewed. Our follow-up study on branch-duct IPMN (93 patients) with EUS revealed that most papillary protrusions show a slow increase in size (48%) or development of lateral spread (LS) (38%). During the follow-up of these patients, 2% developed invasive cancer derived from IPMN and 1% developed invasive cancer concomitant with IPMN. There were two characteristic EUS findings reflecting two different patterns of invasive carcinomas derived from IPMN: The mixed-echo pattern is a finding of the pathway from intestinal-type IPMN to colloid carcinoma, whereas the solid-echo pattern is a finding of the pathway from pancreatobiliary type, oncocytic type and high-grade gastric type to tubular adenocarcinoma. LS along the main pancreatic duct(MPD) was observed in 54% of the 24 patients with branch-duct IPMNs who had undergone preoperative IDUS and surgery, its mean length being 25mm (5-50mm). The diameter of the MPD in the group with LS was 6mm or larger, significantly greater than that in the group without LS (p=0.03). The overall accuracy of IDUS in the detection of LS was 92%. In conclusion, in patients with branch-duct IPMN, EUS is the most adequate imaging modality for the assessment of surgical indication. Preoperative IDUS may be beneficial for the determination of the resection line, especially in patients with an MPD 6mm or greater in diameter.

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Perfusion computed tomography(P-CT) is now available for the analysis of pancreatic blood flow. The aim of this study was to clarify pancreatic blood perfusion in AIP patients and the changes after steroid treatment. Color map imaging of P-CT and pancreatic time CT density curve(TDC) demonstrated that the pancreatic blood flow was attenuated in AIP patients. Pancreatic volumetric blood flow F_V values of 11 AIP patients (82.7/min) were significantly lower than those of 12 normal controls (163.5/min, p=0.0006). AIP patients received steroid treatment and were re-examined, of these, 9 patients showed significantly elevated F_V values after treatment (76.2/min and 109.8/min, p=0.0391, respectively). However, the changes of the values after the treatment differed in varying degrees among the individuals. P-CT is a useful method for the analysis of the blood flow in pancreatic diseases.

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Introduction: We investigated the existence of an ischemic penumbra, which indicates ischemic but still viable lesion, in the early stage of severe acute pancreatitis (SAP).
Methods: Seventy-one consecutive patients with SAP were enrolled. We divided the pancreas into three regions, the head, body and tail, and measured pancreatic blood flow(F_V) and volume(V_D) in each region by perfusion CT with one compartment method within three days after the onset of symptoms. Three weeks later, all patients underwent contrast-enhanced CT to diagnose each region for the development of pancreatic necrosis.
Results: Of the 227 pancreatic regions from 71 SAP patients, 30 regions were diagnosed as positive for pancreatic necrosis. F_V and V_D in regions that developed pancreatic necrosis were significantly lower than those in regions without necrosis (35.7±50.7 vs. 197.0±227.6ml/min, p<0.01 and 2.0±2.6 vs. 8.5±8.8 (%), p<0.01). All 19 regions with F_V <37.5ml/min and V_D <3.4% developed pancreatic necrosis. Of 60 regions with F_V ≥37.5ml/min and V_D <3.4%, 7 (11.7%) developed necrosis and of 7 regions with F_V <37.5ml/min and V_D ≥3.4%, 4 (11.7%) developed necrosis. None of 141 regions with F_V ≥37.5ml/min and V_D ≥3.4% developed necrosis.
Discussion: If F_V or V_D was low, not all regions developed pancreatic necrosis; therefore, we considered that these regions could include zones of ischemic penumbra.

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We have been aggressively performing extensive surgical resections for pancreatic cancer. A cancer-free dissected peripancreatic tissue margin is the most important prognostic factor. To accurately diagnose the extent of peripancreatic tissue invasion intraoperatively, we used both intraoperative ultrasound and intraportal endovascular ultrasonography(IPEUS). For the intraoperative diagnosis of liver metastasis, we used Real-time tissue elastography RTE. With regards to IPEUS technique, we used an 8-French catheter with a rotating radial 20-MHz transducer. IPEUS was the most reliable modality for the diagnosis of portal vein invasion. Intraoperative differential diagnosis of liver metastases is also important for adequate surgical management. The development of RTE has made it possible to visualize tissue elasticity. Using intraoperative RTE enabled us to distinguish accurately between benign tumors and liver metastases. Intraoperative examinations are important in order to perform a successful surgical resection for pancreatic cancer.

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Magnetic resonance(MR) diffusion-weighted imaging(DWI) is a method to visualize the molecular diffusion phenomena. DWI also can measure the diffusivity of molecules as an apparent diffusion coefficient(ADC) value. This study revealed the usefulness of ADC measurement for distinguishing autoimmune pancreatitis from pancreatic carcinoma. ADC measurement can be applied for the differentiation between mucinous cystic neoplasm and intraductal papillary mucinous neoplasm of the pancreas. It is well known, however, that DWI also has major limitation for quantitative evaluation. A new quantitative MR technique, intravoxel incoherent motion(IVIM)-DWI model, might be a solution to this problem.

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The aim of this study was to clarify the role of the accessory papilla in ABP. We examined 4964 cases undergoing endoscopic retrograde cholangiopancreatography(ERCP) which was performed between 1996 and 2008. Forty-six cases in which gallstones were considered to have fallen into the common bile duct and accessory pancreatic duct, clearly identified by ERCP, were included in this study. ABP was diagnosed in 23 cases (ABP group) and in the remaining 23 cases, ABP was not diagnosed but transient acute cholangitis occurred without pancreatitis (AC group). Accessory papilla was patent in one case (1/23: 4%) in the ABP group and in 10 cases (10/23: 43%) in the AC group. Thus, rate of the patency of accessory papilla was significantly lower in the ABP group than in the AC group. Patency of accessory papilla is considered to have a significant impact on the occurrence of ABP in cases where gallstones fall into the common bile duct.

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We investigated the circumstance of antimicrobial therapy for severe acute pancreatitis in elderly patients (70 years or older, n=2111) using the administrative database associated with the Diagnosis Procedure Combination system. Patients were divided into two groups: mild (n=1888) and severe cases (n=223). The proportion of meropenem and imipenem administrated was significantly higher in severe cases than mild cases (p<0.001). In addition, the number of kinds of antimicrobial drugs administrated was also significantly higher in severe cases than mild cases, and the in-hospital mortality rate of patients with severe acute pancreatitis in which five or more antimicrobial drugs had been administrated was significantly high (52.6%). Our results suggest a good compliance of antimicrobial therapy that has been recommended in clinical practice guidelines for severe acute pancreatitis and a difficulty of antimicrobial management for elderly patients.

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The patient, a 62-year-old male, underwent a check-up that indicated an increased serum elastase level. Endoscopic retrograde pancreatography(ERP) revealed irregular stenosis of the main pancreatic duct in the pancreatic tail region and dilatation of the bifurcated pancreatic duct at the same site. Because pancreatic cancer could not be ruled out, a distal pancreatectomy was performed. Histopathological findings of the resected specimen did not suggest malignancy. In the lesion site, a strong PAS-positive, eosinophilic membranaceous foreign body with multinucleated giant cells with features of phagocytosis was discovered adjacent to the main pancreatic duct. Consequently, granulation tissue formation with marked fibrosis was observed. The presence of a PAS-positive foreign body suggested a parasite-mediated etiology. However, no parasite was detected in the resected specimen. Pancreatic disorders in which the involvement of a parasite is suspected are rare; however, some case reports have been published. The present condition should be differentiated from malignant pancreatic diseases.

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A sixteen year old male was admitted to our hospital complaining of anorexia and weight loss. Abdominal echo and CT examination showed a huge mass in the pancreas head. The second portion of duodenum and common bile duct were compressed by a tumor arising from the pancreas head which expanded laterally. A cystic component was seen in the mass, suggesting intratumoral bleeding. The main pancreatic duct was not dilated. A pancreatoblastoma was suspected based on the image findings, patient's age, and high level of serum AFP.
A pancreatoduodenectomy was performed and histopathological examination of resected specimen revealed that the tumor was encapsulated and contained cells with large round nuclei and proliferated to form small ducts or sheet-like patterns. Squamoid corpuscles were seen, and the tumor was diagnosed as pancreatoblastoma. AFP, α-1 antitrypsin, and chromogranin A were stained by immunohistochemistry.
The patient is alive and well now 8 years 5 months after the operation.

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