Histomorphological assessment of isolated abdominal organs after targeted perfusion with the contrast agent Angiofil® in postmortem computed tomography angiography.

The current literature about histological alterations and artefacts associated with postmortem computed tomography angiography (PMCTA) is scarce and limited to qualitative research. The aim of this study was to describe and quantify histological alterations and artefacts in histologic specimens of the inner organs. The spleen, the liver, the kidneys and the pancreas were eviscerated in the course of standard forensic autopsy, followed by manual arterial and venous perfusion of the organs with the lipophilic contrast agent Angiofil®. Computed tomography (CT) of the organ packages was executed to evaluate if the perfusion with Angiofil® was sufficient. The CT scans revealed a good delineation of the vessel trees up to the organ periphery, suggesting a sufficient perfusion. Tissue samples were taken before and after perfusion, stained with hematoxylin-eosin (H&E) and examined by using microscopy. Native and perfused specimens were assessed on the basis of a qualitative rating scale in regard to the integrity of the cells, the tissue architecture and induced alterations. Subsequently the observed differences before and after perfusion with Angiofil® were analyzed quantitatively. While the liver, spleen and kidneys could be evaluated, further microscopic examinations of the pancreatic tissue were not possible due to vast autolytic changes. On the cellular level no changes in the liver, spleen and kidneys were observed after administering Angiofil®. While the tissue architecture of these organs remained intact, a significant blood volume displacement occurred. As a consequence, tissue with hypoemic or normal blood state demonstrated congestion. Further, optically empty spaces emerged regularly in the vessels and the parenchyma of each organ as a surrogate for the lipophilic contrast agent. With a few exceptions an adequate perfusion up to the microscopic level was observed. Following the results of this investigation, CT-controlled manual injection of Angiofil® into isolated organs may be an alternative to the generalized in situ application of contrast agents in the course of PMCTA. It is of eminent importance to know the artefacts induced by an Angiofil® injection in order to avoid a misinterpretation or a masking of findings. Thus, a collection of native tissue specimens has to be done before contrast agent application.

[Robot-assisted pancreatic resection]. / Roboterassistierte Pankreasresektion.

Although robot-assisted pancreatic surgery has been considered critically in the past, it is nowadays an established standard technique in some centers, for distal pancreatectomy and pancreatic head resection. Compared with the laparoscopic approach, the use of robot-assisted surgery seems to be advantageous for acquiring the skills for pancreatic, bile duct and vascular anastomoses during pancreatic head resection and total pancreatectomy. On the other hand, the use of the robot is associated with increased costs and only highly effective and professional robotic programs in centers for pancreatic surgery will achieve top surgical and oncological quality, acceptable operation times and a reduction in duration of hospital stay. Moreover, new technologies, such as intraoperative fluorescence guidance and augmented reality will define additional indications for robot-assisted pancreatic surgery.

Objective Assessment of Surgical Restaging after Concurrent Chemoradiation for Locally Advanced Pancreatic Cancer.

The role of neoadjuvant chemoradiation therapy in locally advanced pancreatic cancer (LAPC) is still controversial. The aim of this study was to evaluate surgical downstaging after concurrent chemoradiation therapy (CCRT) for LAPC by measuring the objective changes after treatment. From January 2003 through July 2011, 54 patients with LAPC underwent neoadjuvant CCRT. Computed tomography findings of the tumor size, including major vessel invasion, were analyzed before and after CCRT. Among the total recruited patients, 14 had borderline resectable malignancy and another 40 were unresectable before CCRT. After CCRT, a partial response was achieved in four patients. Stable disease and further disease progression were achieved in 36 and 14 patients, respectively. Tumor size showed no significant difference before and after CCRT (3.6 ± 1.1 vs. 3.6 ± 1.0 cm, P = 0.61). Vessel invasion showed improvement in two patients, while 13 other patients showed further tumor progression. Thirty-nine patients with unresectable malignancy and 11 patients with borderline resectable malignancy at time of initial diagnosis remained unchanged after CCRT. Four patients with borderline pancreatic malignancy progressed to an unresectable stage, whereas one unresectable pancreatic malignancy improved to a borderline resectable stage. Only one patient with borderline resectable disease underwent operation after CCRT; however, curative resection failed due to celiac artery invasion and peritoneal seeding. The adverse events associated with CCRT were tolerable. In conclusion, preoperative CCRT in LAPC rarely leads to surgical downstaging, and it could lower resectability rates.

Temporal assessment of pancreatic blood flow and perfusion following secretin stimulation using noninvasive MRI.

PURPOSE: To dynamically quantify pancreatic perfusion and flow within the arteries supplying the pancreas in response to secretin stimulation. MATERIALS AND METHODS: Twelve healthy male subjects were scanned at 1.5T with arterial spin labeling to measure tissue perfusion and phase contrast magnetic resonance imaging (MRI) to measure vessel flow. Superior mesenteric (SMA), gastroduodenal (GDA), common hepatic (HA), and splenic (SA) arterial flow and pancreatic perfusion were serially measured for 50 minutes following 1 IU/kg intravenous secretin. The significance of differences between timepoints was tested using a repeated measures one-way analysis of variance (ANOVA). RESULTS: Baseline blood flow (mean ± SEM or median [IQR]) for SMA, HA, SA, and GDA was 7.6 ± 1.3, 4.0 ± 0.5, 8.2 ± 0.8, and 0.9 (0.8-1.4) ml/s, respectively. Baseline pancreatic perfusion was 200 ± 25 ml/100g/min. Blood flow increased in the SMA (234%, P < 0.0001) and GDA (155%, P = 0.015) immediately after secretin injection. Reduced HA blood flow was observed after 10 minutes (P = 0.066) with no change in SA flow (P = 0.533). Increased pancreatic perfusion was maintained for 40 minutes after injection with a maximal increase at 5 minutes (16.8%, P = 0.025). CONCLUSION: Intravenous secretin resulted in significant temporal changes in pancreatic perfusion and arterial blood flow.

Dynamic contrast-enhanced (DCE) MRI assessment of microvascular characteristics in the murine orthotopic pancreatic cancer model.

OBJECT: The aim of this study was to assess the dynamic contrast enhanced magnetic resonance imaging (DCE-MRI)-derived pharmacokinetic parameters between two contrast agents in a murine orthotopic pancreatic cancer model and to evaluate the tumor heterogeneity and the potential association between kinetic parameters and angiogenic markers such as the microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression by immunohistochemistry. MATERIALS AND METHODS: Human pancreatic adenocarcinoma cell line MIAPaCa-2 was injected into the pancreas of BALB/C nu/nu mice. DCE-MRI was performed using Gd-DTPA and Gd-EOB-DTPA. Quantitative and semi-quantitative vascular parameters (K(trans), Kep, Ve and AUC) were calculated by using a dedicated postprocessing software program. Values were compared with tumor rim, tumor core and the entire tumor. The MVD and VEGF expressions between tumor rim and tumor core were also compared. RESULTS: There were no significant differences in K(trans), Kep, Ve, and AUC values of the three groups when using Gd-DTPA. However there were significant differences in K(trans), Kep, and AUC values of the three groups when using Gd-EOB-DTPA (P=0.014, 0.022, 0.007, respectively), in addition, the K(trans) and Kep values of tumor core were significantly lower than those of the entire tumor (adjusted P=0.014 and 0.027, respectively), the AUC values of core were significantly lower than those of the entire tumor and rim (adjusted P=0.039 and 0.009, respectively). Immunohistology results revealed that MVD and VEGF expression in the tumor rim was significantly higher than that in the core. There was positive correlation between AUC and MVD, VEGF. CONCLUSION: The murine orthotopic pancreatic cancer model provides an ideal animal model to study human pancreatic cancer. It can more sensitively semi-quantitatively and quantitatively analyze tumor angiogenesis through selecting the albumin-binding contrast agent.

Hemodynamic assessment of celiaco-mesenteric anastomosis in patients with pancreaticoduodenal artery aneurysm concomitant with celiac artery occlusion using flow-sensitive four-dimensional magnetic resonance imaging.

OBJECTIVES: Many pancreaticoduodenal artery (PDA) aneurysms are associated with celiac artery (CA) stenosis. The pathogenesis of PDA aneurysm may be associated with hemodynamic changes due to CA stenosis/occlusion. The aim of this study was to assess the hemodynamic changes of celiaco-mesenteric anastomosis in patients with PDA aneurysms concomitant with CA occlusion using four-dimensional flow-sensitive magnetic resonance imaging (4D-Flow). METHODS: 4D-Flow was performed preoperatively on five patients. Seven age- and sex-matched individuals were used as controls. Hemodynamic parameters such as flow volume and maximum flow velocity in PDAs, gastroduodenal arteries, common hepatic arteries, and superior mesenteric arteries were compared between both groups. Wall shear stress (WSS) and oscillatory shear index (OSI) were mapped in both groups. RESULTS: In the patient group, 4D-Flow identified retrograde flow of both gastroduodenal arteries and common hepatic arteries. Heterogeneous distribution patterns of both WSS and OSI were identified across the entire PDA in the patient group. OSI mapping showed multiple regions with extremely high OSI values (OSI > 0.3) in all patients. All PDA aneurysms, which were surgically resected, were atherosclerotic. CONCLUSIONS: 4D-Flow identified hemodynamic changes in celiaco-mesenteric arteries in patients with PDA aneurysms with concomitant CA occlusion. These hemodynamic changes may be associated with PDA aneurysm formation.

Concomitant vascular reconstruction during pancreatectomy for malignant disease: a propensity score-adjusted, population-based trend analysis involving 10,206 patients.

OBJECTIVE: To assess trends in the frequency of concomitant vascular reconstructions (VRs) from 2000 through 2009 among patients who underwent pancreatectomy, as well as to compare the short-term outcomes between patients who underwent pancreatic resection with and without VR. DESIGN: Single-center series have been conducted to evaluate the short-term and long-term outcomes of VR during pancreatic resection. However, its effectiveness from a population-based perspective is still unknown. Unadjusted, multivariable, and propensity score-adjusted generalized linear models were performed. SETTING: Nationwide Inpatient Sample from 2000 through 2009. PATIENTS: A total of 10,206 patients were involved. MAIN OUTCOME MEASURES: Incidence of VR during pancreatic resection, perioperative in-hospital complications, and length of hospital stay. RESULTS: Overall, 10,206 patients were included in this analysis. Of these, 412 patients (4.0%) underwent VR, with the rate increasing from 0.7% in 2000 to 6.0% in 2009 (P < .001). Patients who underwent pancreatic resection with VR were at a higher risk for intraoperative (propensity score-adjusted odds ratio, 1.94; P = .001) and postoperative (propensity score-adjusted odds ratio, 1.36; P = .008) complications, while the mortality and median length of hospital stay were similar to those of patients without VR. Among the 25% of hospitals with the highest surgical volume, patients who underwent pancreatic surgery with VR had significantly higher rates of postoperative complications and mortality than patients without VR. CONCLUSIONS: The frequency of VR during pancreatic surgery is increasing in the United States. In contrast with most single-center analyses, this population-based study demonstrated that patients who underwent VR during pancreatic surgery had higher rates of adverse postoperative outcomes than their counterparts who underwent pancreatic resection only. Prospective studies incorporating long-term outcomes are warranted to further define which patients benefit from VR.

Tissue perfusion in pathologies of the pancreas: assessment using 128-slice computed tomography.

PURPOSE: Perfusion CT can provide information regarding blood perfusion and permeability in (tumor) tissues in a non-invasive manner. In this study, values of CT perfusion parameters in several pancreas pathologies were determined and compared to a control population. MATERIALS AND METHODS: Dynamic 128-slice perfusion CT was performed in patients admitted to the radiology department between June 2010 and March 2011. Included pathologies were pancreatic adenocarcinoma, acute and chronic pancreatitis, neuroendocrine tumors, and (pseudo)cystic lesions. Parametric mappings of blood flow, blood volume, and permeability surface area product were generated. RESULTS: Blood flow and blood volume were significantly lower in acute and chronic pancreatitis compared to the control group. In the center of adenocarcinoma tumors, low blood flow and blood volume was observed, gradually increasing toward the tumor rim; perfusion values in pancreatic parenchyma adjacent to the tumor were not significantly different from the control population. In neuroendocrine tumors, significantly increased perfusion values were observed. CONCLUSION: Compared to the control population, significant decreases in perfusion values were observed in all pancreatic pathologies under study, except in neuroendocrine tumors. Perfusion CT values can be used as an additional parameter to differentiate pancreatic pathologies.

Assessment of tumor vascularization in pancreatic adenocarcinoma using 128-slice perfusion computed tomography imaging.

OBJECTIVE: Computed tomography (CT) perfusion studies can provide valuable information regarding tumor vascularization. We report on a study assessing CT perfusion characteristics in the normal pancreas and in patients with pancreatic adenocarcinoma. METHODS: Twenty healthy subjects and 20 patients with histologically confirmed pancreatic adenocarcinoma were included in the study after written informed consent and approval by our institutional review board. All subjects underwent perfusion CT imaging of the pancreas using 128-slice dual-source CT. The scanning sequence included 18 scans. Parametric maps of blood volume (BV), blood flow (BF), and permeability surface area product (PS) were generated and compared with density measurements. RESULTS: In normal pancreas, no significant difference in perfusion values was observed between head, body, and tail of the pancreas. Mean organ values were 76.76 (SD, 15.6) mL/100 g/min, 15.80 (SD, 2.40) mL/100 g, and 27.74 (SD, 16.8) mL/100 g/min for BF, BV, and PS, respectively. Compared with the normal pancreas, a 60% reduction in BF and BV was observed in the tumor tissue. Perfusion values gradually increased toward the tumor rim. Necrotic tumor areas were identified in 25% of patients. No significant differences were observed when comparing normal pancreas and healthy pancreatic tissue in adenocarcinoma patients. CONCLUSIONS: The feasibility of whole-tumor perfusion imaging using 128-slice CT was demonstrated in patients with pancreatic adenocarcinoma. Perfusion CT provides additional information compared with image assessment based on density measurements (Hounsfield units) and allows noninvasive assessment of vascularization in the tumor tissue.

Correlation between angiogenesis and islet graft function in diabetic mice: magnetic resonance imaging assessment.

BACKGROUND/PURPOSE: Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was used to evaluate neovascularization after intravenous injection of gadolinium, where contrast leaks out of new vessels and remains within the tissues. We examined the relationship between DCE-MRI and metabolic parameters such as blood glucose, serum insulin and glucose tolerance test (GTT) after intraportal islet transplantation. METHODS: Streptozotocin-induced diabetic BALB/c mice (n = 15) received syngeneic intraportal islet transplantation (500 islet equivalent). Blood glucose, serum insulin and GTT were evaluated till postoperative day (POD) 14. Liver DCE-MRI was performed at POD 3, 7 and 14. Correlations between DCE-MRI and metabolic parameters were examined using regression analysis. RESULTS: Eight mice achieved normoglycemia after intraportal transplantation. At POD 3 a significant but moderate correlation between DCE-MRI and blood glucose was found. No DCE-MRI or metabolic parameters correlated at POD 7. However, at POD 14 strong or moderate correlations between DCE-MRIs were found: negative correlations with blood glucose (R (2) = 0.86) and GTT (R (2) = 0.48) but a positive correlation with serum insulin (R (2) = 0.32). CONCLUSION: We report that DCE-MRI can reflect the metabolic and functional condition of the transplanted islets.

Incidence and management of arterial anomalies in patients undergoing pancreaticoduodenectomy.

CONTEXT: Pancreaticoduodenectomy entails ligation of vascular arcades arising from the celiac and superior mesenteric arteries. These are known to have anatomical variations. OBJECTIVE: This study was aimed at analyzing the spectrum of arterial anomalies and their clinical impact on the procedure itself. PATIENTS: The study includes 200 consecutive patients who underwent a pancreaticoduodenectomy between September 2003 and May 2009 after excluding those having distant metastases or local unresectability. MAIN OUTCOME MEASURES: The records of the patients were studied to assess the incidence of arterial anomalies and the operative complexities involved in a pancreaticoduodenectomy. RESULTS: Fifty-three patients (26.5%) had arterial anomalies. The complexity of the surgery was determined by the course of these arteries. The mean duration of surgery was 420 + or - 32.0 minutes in patients with arterial anomalies versus 370 + or - 38.5 minutes in those with a normal arterial anatomy (P=0.005). Fifty-one out of 53 (96.2%) patients underwent pancreaticoduodenectomy with negative resection margins. The pancreaticoduodenectomy was abandoned in two cases due to patient- and tumor-related factors. CONCLUSION: During pancreaticoduodenectomy, arterial anomalies can increase operative complexity but do not usually compromise the safety of the procedure or its oncological outcome.

True pancreaticoduodenal artery aneurysms: a decision analysis.

PURPOSE: True pancreaticoduodenal artery aneurysms are rare. No definitive study evaluating the natural history of these lesions or their preferred method of treatment has been published. The purpose of this study was to evaluate the outcome of preventive treatment of unruptured pancreaticoduodenal artery aneurysms using a Markov model. MATERIALS AND METHODS: With the use of a Markov model, we performed a decision analysis to evaluate the outcome of preventive treatment of unruptured pancreaticoduodenal artery aneurysms. The risk of rupture and the mortality of preventive treatment are unknown. Therefore, we performed sensitivity analysis using these parameters. Effectiveness was measured in life expectancy. RESULTS: For 80-year-old patients, preventive treatment was dominated by no treatment if mortality rates of preventive treatment were greater than 1.4%, greater than 2.6%, greater than 3.8%, and greater than 4.8% at annual rupture rates of 1%, 2%, 3%, and 4%, respectively. For 50-year-old patients, preventive treatment was dominated by no treatment if mortality rates of preventive treatment were greater than 3.3%, greater than 5.9%, greater than 8.0%, and greater than 9.7% at annual rupture rates of 1%, 2%, 3%, and 4%, respectively. CONCLUSION: The effectiveness of preventive treatment of unruptured pancreaticoduodenal artery aneurysms depends on the aneurysm rupture rate, mortality rate of preventive treatment, and patient age. Taking into account the effects of these parameters is important in making treatment decisions.

Stenosis of the third portion of the duodenum due to bleeding from the anterior pancreaticoduodenal artery: assessment by multiphase contrast-enhanced examination with multislice CT.

BACKGROUND: This study was undertaken to analyze the CT findings for the rare pathological process that stenosis of the third portion of the duodenum was presumed to be caused by bleeding from the anterior pancreaticoduodenal artery. METHODS: Four consecutive patients presenting with frequent vomiting, who did not have well-known underlying disorders causing duodenal stenosis, were retrospectively recruited. Multiphase contrast-enhanced CT examinations were performed with 0.5- or 1-mm collimation. Two radiologists evaluated 2-mm axial and multiplanar reformatted images. RESULTS: In all patients, endoscopy demonstrated severe edematous stenosis of the third portion of the duodenum not associated with ulcer, bleeding, or neoplasm. The following CT findings were observed in all patients: homogenous swelling of the third portion of the duodenum associated with luminal stenosis in un-enhanced images, a band-like area of lower contrast-enhancement surrounding the walls of the third portion of the duodenum in pancreatic-phase images, and stenosis of the celiac axis. In three patients, aneurysms of the anterior pancreaticoduodenal artery in arterial-phase images were depicted. In the remaining patient, the diameter of the artery was irregular. CONCLUSIONS: Multiphase contrast-enhanced CT examination using a multislice CT scanner helps to establish the diagnosis of this pathological process.

Arteriovenous malformation of the pancreas: assessment of clinical and multislice CT features.

BACKGROUND: This study was undertaken to analyze the clinical and CT features of arteriovenous malformation (AVM) of the pancreas. METHODS: Seven lesions in six consecutive patients (one woman and five men, mean age 51 years) with AVM of the pancreas who underwent multiphase contrast-enhanced CT with 0.5 or 1-mm collimation were retrospectively studied. CT images were evaluated and correlated with angiographic findings by two radiologists. RESULTS: In four patients, the lesions were incidental findings. Two patients presented with abdominal pain and gastrointestinal bleeding, respectively. Serum amylase levels were within normal limits in all patients. The mean size of the lesions was 32.1 mm (3.0-97.3 mm). Conglomeration of strong nodular stains and early enhancement of the portal venous system were observed for all the lesions. The diagnosis of AVM of the pancreas was retrospectively established for all lesions, but was prospectively established for four lesions. The feeding arteries of all lesions were depicted, showing agreement with those observed by angiography performed for four lesions. One lesion showed pseudocyst formation, haziness around the lesion, and strong enhancement of the duodenal wall. CONCLUSION: Multiphase CT examination using multislice CT is useful for diagnosis of AVM of the pancreas, including identification of the feeding arteries.

Pancreaticoduodenectomy with vascular resection for local advanced pancreatic head cancer: a single center retrospective study.

INTRODUCTION: Pancreaticoduodenectomy with vascular resection remains a controversial approach for patients with local advanced pancreatic head cancer for the lack of evidences of survival and quality of life benefits. The aim of this study was to evaluate whether patients of pancreatic head cancer benefit on quality of life, survival, and treatment cost from pancreaticoduodenectomy with vascular resection compared with palliative therapy. MATERIALS AND METHODS: Two hundred fourteen patients of pancreatic head cancer whose pancreatic head could not be dissected free from adjacent vascular were involved in this study. Eighty of these patients underwent pancreaticoduodenectomy with vascular resection, whereas other patients underwent palliative therapy. RESULTS: Pancreaticoduodenectomy with artery resection offered worse outcomes on almost all aspects of quality of life and survival compared with palliative therapy. Pancreaticoduodenectomy with vein resection offered better 5-year survival compared with palliative therapy, whereas palliative therapy offered better quality of life after surgery. CONCLUSION: Pancreaticoduodenectomy with artery resection is nonsensical on treatment of pancreatic head cancer with artery adhesion/invasion. As for patients with vein adhesion/invasion, pancreaticoduodenectomy with vein resection should be performed cautiously. When actual vein invasion is very possible to have taken place, the choice of treatment strategy should be considered carefully by the pancreatic surgeons.

Pancreatic perfusion: noninvasive quantitative assessment with dynamic contrast-enhanced MR imaging without and with secretin stimulation in healthy volunteers--initial results.

PURPOSE: To prospectively quantify pancreatic regional perfusion with dynamic contrast material-enhanced magnetic resonance (MR) imaging by using a one-compartment model and to assess perfusion changes during secretin stimulation in healthy volunteers. MATERIALS AND METHODS: The study had institutional review board approval, and written informed consent was obtained. Ten healthy volunteers (five men, five women; mean age, 24.7 years +/- 1.9 [standard deviation]; range, 22-29 years) underwent MR imaging pancreatic perfusion studies performed twice without secretin and twice during secretin stimulation. Dynamic contrast-enhanced MR imaging consisted of saturation-recovery T1-weighted turbo-field-echo imaging with peripheral pulse triggering and respiratory tracking. A dose of 0.05 mmol gadodiamide per kilogram of body weight was injected at a rate of 3.5 mL/sec. Regional perfusion parameters were fitted with a one-compartment model. The analysis of variance test for repeated measurements was used to assess differences in pancreatic perfusion without and that with secretin administration. RESULTS: Significant differences in perfusion parameters between the three pancreatic regions were observed (P < .05). During secretin stimulation, a significant difference was observed only between the body and the tail of the pancreas (P = .02). A significant increase (P = .003) in pancreatic perfusion was observed after secretin administration. Mean pancreatic perfusion was 184 mL/min/100 g of tissue +/- 71, 207 mL/min/100 g +/- 77, and 230 mL/min/100 g +/- 87 without secretin and 342 mL/min/100 g +/- 154, 338 mL/min/100 g +/- 156, and 373 mL/min/100 g +/- 176 after secretin stimulation in the head, body, and tail of the pancreas, respectively. Intraindividual variability was 21% without secretin stimulation and 46% with secretin stimulation. CONCLUSION: Dynamic contrast-enhanced MR imaging enables noninvasive quantification of regional pancreatic perfusion in resting conditions and demonstrates the increase in pancreatic perfusion during secretin stimulation in healthy subjects.

Reducing diabetes incidence through the inhibition of the renin-angiotensin system: a strategy for reducing cardiovascular mortality and morbidity?

The prevalence of type 2 diabetes is increasing worldwide, and prevention of the disease is a key objective. Several clinical trials reported a consistent reduction in the incidence of newly diagnosed diabetes in high-risk patients treated with renin-angiotensin system-inhibiting drugs. In all those trials, however, diabetes reduction was either a post-hoc analysis result or a secondary endpoint. Therefore, we need the results of ongoing specific prospectively designed trials, with new-onset diabetes as the principal endpoint.

CT depiction of small arteries in the pancreatic head: assessment using coronal reformatted images with 16-channel multislice CT.

BACKGROUND: To assess the capabilities of 16-channel multislice CT in acquiring almost exclusively arterial-phase images of the pancreas and depicting small pancreatic arteries in coronal reformatted images. MATERIALS AND METHODS: In 45 consecutive patients, arterial-phase contrast enhancement was measured in the aorta and its branches, portal venous system, and pancreas. Coronal reformatted images of 1.2- or 1.3-mm slice thickness at 0.8- or 0.9-mm intervals were generated from axial images acquired with 0.5-mm collimation. Two radiologists evaluated the quality of imaging in the arterial phase and the visibility of the pancreatic arteries in coronal reformatted images. RESULTS: Mean enhancement in the aorta and its branches was greater than 300 HU, while that in the portal venous system and pancreas was less than 100 HU. The images were judged to be suitable for delineating the pancreatic arteries in all patients. The following arteries were visualized: anterior superior pancreaticoduodenal (39 patients), posterior superior pancreaticoduodenal (41), anterior inferior pancreaticoduodenal (39), posterior inferior pancreaticoduodenal (33), dorsal pancreatic (42), its right branch (34), and transverse pancreatic (37). CONCLUSION: Multislice CT can depict small pancreatic arteries using coronal reformatted images generated from almost exclusively arterial-phase axial images acquired with 0.5-mm collimation.

Dynamic intravital fluorescence microscopy--a novel method for the assessment of microvascular permeability in acute pancreatitis.

Edema formation is the first manifestation of acute pancreatitis. Microcirculatory derangements like leukocyte-endothelial cell interaction and perfusion failure result in enhancement of microvascular permeability to large molecules playing a pivotal role in the progression of the acutely altered pancreatic tissue. Due to the lack of suitable methods the crucial mechanisms of enhanced permeability in vivo are not very well investigated. Sprague-Dawley rats were randomly assigned to three groups: (a) sham operated animals with normal pancreas, (b) the pancreatitis group induced by 60 min temporary occlusion of the arterial supply followed by reperfusion and (c) the histamine group in which the pancreas was superfused with 10(-5)M histamine. The pharmacokinetics of tetramethylrhodamine-labelled BSA in the intravital microscopic images of a capillary network of the pancreas were densitometrically quantified over 20 min. From these data the effective microvascular permeability was calculated taking also into account morphology of microvessels, elimination rate of the tracer from the intravascular space and capillary microhematocrit. In addition macromolecular leakage of gold-labelled BSA was investigated by electron microscopy. Microvascular permeability was 0.10 +/- 0.02 x 10(-7) cm/s, 0.49 +/- 0.04 x 10(-7) cm/s and 1.21 +/- 0.29 x 10(-7) cm/s for control, ischemia and histamine group, respectively (P < 0.05 ischemia, histamine vs. control and ischemia vs. histamine). Electron microscopy revealed albumin extravasation in the last two groups. We established a technique allowing to quantify microvascular permeability in pancreatic tissue by dynamic intravital microscopy being independent of the investigator. This technique enabling accurate pathophysiologic characterisation in terms of edema formation can form the basis for evaluating in the future novel treatment strategies directed against acute pancreatitis.

Noninvasive in vivo assessment of the pancreatic microcirculation: orthogonal polarization spectral imaging.

INTRODUCTION: Capillary perfusion failure of the pancreatic microcirculation is characteristic in the pathogenesis of acute pancreatitis and ischemia-reperfusion damage after pancreas transplantation. Up to now, no logistic suitable method for analyzing pancreatic capillary perfusion during operations in humans has been established without the use of fluorescent dyes. AIM: To compare the well-established technique of intravital epifluorescence microscopy with the novel noninvasive method of orthogonal polarization spectral (OPS) imaging for measurement of the pancreatic functional capillary density. METHODOLOGY: In eight anesthetized rats, six identical capillary regions of interest per animal were measured by both methods, and the results were compared. RESULTS: Absolute values from the capillary perfusion data were not significantly different between the two methods (fluorescence microscopy: 394 +/- 44 cm/cm2; OPS imaging: 385 +/- 45 cm/cm2). Correlation parameters were significant, and Bland-Altman analyses showed good agreement with a mean difference (bias) between the two methods of 6.9 cm/cm2, indicating that slightly smaller values are measured with OPS imaging. CONCLUSION: OPS imaging is a valid noninvasive method that analyzes the pancreatic microcirculation as accurately as the established intravital microscopy technique and therefore could be useful for clinical research and diagnosis during transplantation and operations.