Lars Grenacher

Intravoxel incoherent motion MRI for the differentiation between mass forming chronic pancreatitis and pancreatic carcinoma.

Purpose:To determine which of the quantitative parameters obtained from intravoxel incoherent motion diffusion weighted imaging (DWI) is the most significant for the differentiation between pancreatic carcinoma and mass-forming chronic pancreatitis. Materials and Methods:Twenty-nine patients with pancreatic masses were included, 9 proved to have a mass-forming pancreatitis and 20 had a pancreatic carcinoma. The patients were studied using intravoxel incoherent motion DWI with 11 b-values and the apparent diffusion coefficient (ADC), the true diffusion constant (D) and the perfusion fraction (f) were calculated. The diagnostic strength of the parameters was evaluated using receiver operating characteristic analysis. Results:The ADC in chronic pancreatitis was higher than in pancreatic carcinoma with significant differences at b = 50, 75, 100, 150, 200, 300 s/mm2 (ADC50 = 3.17 ± 0.67 vs. 2.55 ± 1.09, ADC75 = 2.46 ± 0.4 vs. 1.93 ± 0.52, ADC100 = 2.28 ± 0.48 vs. 1.73 ± 0.45, ADC150 = 1.97 ± 0.26 vs. 1.63 ± 0.40, ADC200 = 1.98 ± 0.24 vs. 1.53 ± 0.28, and ADC300 = 1.76 ± 0.19 vs. 1.46 ± 0.31 × 10−3 mm2/s). No significant differences were found at b = 25, 400, 600, and 800 s/mm2 (ADC25 = 4.69 ± 0.65 vs. 4.04 ± 1.35, ADC400 = 1.57 ± 0.21 vs. 1.37 ± 0.30, ADC600 = 1.38 ± 0.18 vs. 1.24 ± 0.25, and ADC800 = 1.27 ± 0.10 vs. 1.18 ± 0.19 × 10−3 mm2/s) nor using ADCtot (1.42 ± 0.23 vs. 1.28 ± 0.12 × 10−3 mm2/s). The perfusion fraction f was significantly higher in pancreatitis compared with pancreatic carcinoma (16.3% ± 5.30% vs. 8.2% ± 4.00%, P = 0.0001). There was no significant difference between groups for D (1.07 ± 0.224 × 10−3 mm2/s for chronic pancreatitis and 1.09 ± 0.3 × 10−3 mm2/s for pancreatic carcinoma, P = 0.66). For f, the highest area under the curve (0.894) and combined sensitivity (80%) and specificity (89.9%) were found. Conclusions:There were significant differences in ADC50–300 between chronic pancreatitis and pancreatic carcinoma. Because D is not significantly different between groups, differences in ADC can be attributed mainly to differences in perfusion. The perfusion fraction f proved to be the superior DWI-derived parameter for differentiation of mass-forming pancreatitis and pancreatic carcinoma.

A systematic review of localization, surgical treatment options, and outcome of insulinoma.

Objective Insulinoma with an incidence of 0.4% is a rare pancreatic tumor. Preserving surgery is the treatment of choice. Exact localization is necessary to plan the appropriate approach. This article gives an overview on localization and surgical strategies for treatment of insulinoma. Methods In this systematic review, 114 articles with 6222 cases of insulinoma were reviewed with emphasis on localization techniques and surgical treatment. Results Insulinoma happens mostly in the fifth decade of life, with a higher incidence in men. They occur mostly sporadic (94%), benign (87%), and single (90%). Insulinomas are mostly smaller than 20 mm (84%). The tumors are distributed almost equally in the pancreas. Conclusions Computed tomography is routinely used as first choice preoperatively. Intraoperative inspection, palpation, and sonography were applied with high success rate. Intraoperative sonography is considered as the most reliable technique. Enucleation is the most administered type of surgery (56%). Different types of resection include distal pancreatectomy (32%), Whipple procedure (3%), and subtotal pancreatectomy (<3%). Despite the development of laparoscopy, open approach is the favorite method (90%). The most common surgical complication is fistula. The mortality rate of open approach was higher (4vs0%). Despite high cure rate, recurrence of insulinoma occurs in 7% after surgery.

Cachexia but not obesity worsens the postoperative outcome after pancreatoduodenectomy in pancreatic cancer

BACKGROUND Prognosis after pancreatoduodenectomy for pancreatic cancer is determined by tumor characteristics, completeness of resection, and patients comorbidity. Our aim was to assess the effects of body mass and fat distribution on the postoperative course after pancreatoduodenectomy. METHODS Of 2,968 pancreatic resections, 408 patients with primary pancreatic adenocarcinoma who underwent pancreatoduodenectomy and of whom cross sectional images were available were identified and followed-up in a prospective database. Preoperative computed tomographic or magnetic resonance imaging scans were analyzed for abdominal wall fat, hip girdle fat, visceral fat, and abdominal depth. Peri- and postoperative parameters, including preoperative unintentional weight loss, cachexia-associated serum parameters, nonoperative and operative complications, and mortality and long-term survival were evaluated and correlated with body mass index and fat distribution. RESULTS Patients with low body mass index had a greater 90-day mortality (P = .048) and a trend toward greater complication rates and in-hospital mortality, despite a greater comorbidity in obese patients with a higher body mass index. Accordingly, patients with large amounts of abdominal wall fat had fewer intra-abdominal abscesses (P = .047), lower in-hospital (P = .019) and 90-day mortality rates (P = .007), and better long-term survival (P = .016). CONCLUSION In pancreatic cancer, underweight but not obese patients have a poor outcome after pancreatoduodenectomy. This observation emphasizes the need for pre- and perioperative therapeutic improvements in the setting of pancreatic cancer-associated cachexia.

Retained surgical sponge with migration into the duodenum and persistent duodenal fistula.

Abstract. Migration of a retained surgical sponge into the bowel is a rare cause of bowel obstruction. Thus far, there have not been any reports that the site of initial migration of the sponge was identified by imaging studies or surgical exploration because the onset of symptoms is usually delayed. Unique about the case presented herein is that a barium meal follow-through study revealed a duodenual fistula that had developed after uneventful cholecystectomy due to a retained surgical sponge that had migrated into the duodenum and obstructed the distal jejunum. Imaging findings are presented and discussed.

Pharmacodynamics of streptavidin-coated cyanoacrylate microbubbles designed for molecular ultrasound imaging

Objectives:To assess the pharmacodynamic behavior of cyanoacrylate, streptavidin-coated microbubbles (MBs) and to investigate their suitability for molecular ultrasound imaging. Materials and Methods:Biodistribution of MBs was analyzed in tumor-bearing mice using &ggr;-counting, immunohistochemistry, flow cytometry, and ultrasound. Further, vascular endothelial growth factor receptor 2-antibody coupled MBs were used to image tumor neovasculature. Results:After 1 minute >90% of MBs were cleared from the blood and pooled in the lungs, liver, and spleen. Subsequently, within 1 hour a decent reincrease of MB-concentration was observed in the blood. The remaining MBs were removed by liver and spleen macrophages. About 30% of the phagocytosed MBs were intact after 48 hours. Shell fragments were found in the kidneys only. No relevant MB-accumulation was observed in tumors. In contrast, vascular endothelial growth factor receptor 2-specific MBs accumulated significantly within the tumor vasculature (P < 0.05). Conclusions:The pharmacokinetic behavior of streptavidin-coated cyanoacrylate MBs has been studied. In this context, the low amount of MBs in tumors after >5 minutes is beneficial for specific targeting of angiogenesis.

Dual-energy perfusion-CT of pancreatic adenocarcinoma

PURPOSE To evaluate the feasibility of dual-energy CT (DECT)-perfusion of pancreatic carcinomas for assessing the differences in perfusion, permeability and blood volume of healthy pancreatic tissue and histopathologically confirmed solid pancreatic carcinoma. MATERIALS AND METHODS 24 patients with histologically proven pancreatic carcinoma were examined prospectively with a 64-slice dual source CT using a dynamic sequence of 34 dual-energy (DE) acquisitions every 1.5s (80 ml of iodinated contrast material, 370 mg/ml, flow rate 5 ml/s). 80 kV(p), 140 kV(p), and weighted average (linearly blended M0.3) 120 kV(p)-equivalent dual-energy perfusion image data sets were evaluated with a body-perfusion CT tool (Body-PCT, Siemens Medical Solutions, Erlangen, Germany) for estimating perfusion, permeability, and blood volume values. Color-coded parameter maps were generated. RESULTS In all 24 patients dual-energy CT-perfusion was. All carcinomas could be identified in the color-coded perfusion maps. Calculated perfusion, permeability and blood volume values were significantly lower in pancreatic carcinomas compared to healthy pancreatic tissue. Weighted average 120 kV(p)-equivalent perfusion-, permeability- and blood volume-values determined from DE image data were 0.27 ± 0.04 min(-1) vs. 0.91 ± 0.04 min(-1) (p<0.0001), 0.5 ± 0.07 *0.5 min(-1) vs. 0.67 ± 0.05 *0.5 min(-1) (p=0.06) and 0.49 ± 0.07 min(-1) vs. 1.28 ± 0.11 min(-1) (p<0.0001). Compared with 80 and 140 kV(p) the standard deviations of the kV(p)120 kV(p)-equivalent values were manifestly smaller. CONCLUSION Dual-energy CT-perfusion of the pancreas is feasible. The use of DECT improves the accuracy of CT-perfusion of the pancreas by fully exploiting the advantages of enhanced iodine contrast at 80 kV(p) in combination with the noise reduction at 140 kV(p). Therefore using dual-energy perfusion data could improve the delineation of pancreatic carcinomas.

A New Invasion Score for Determining the Resectability of Pancreatic Carcinomas with Contrast-Enhanced Multidetector Computed Tomography

Objective: It was the aim of this study to evaluate a new infiltration score to determine the resectability of pancreatic carcinomas in preoperative planning. Materials and Methods: Eighty patients with suspected pancreatic tumor were examined prospectively using 16-row spiral CT. The scans were evaluated for the presence of pancreatic carcinoma, peripancreatic tumor extension and vascular invasion using a standardized questionnaire. Invasion of the surgically relevant vessels was evaluated using a new invasion score. The operative and histological findings and the clinical follow-up served as the gold standard. Results: Forty patients had a pancreatic carcinoma, 5 had metastasis of a different primary tumor, and in 35 patients, there was no malignant pancreatic disease. The sensitivity for tumor detection was 100%, with a specificity of 88% for differentiating between malignant and benign pancreatic tumors. Invasion of the surrounding vessels was evaluated correctly using the invasion score, with a sensitivity of 89% and a specificity of 99%. In evaluation of resectability, a sensitivity of 94% and a specificity of 89% were achieved. Conclusion: Using 16-row spiral CT, the invasion score is a valid tool for correctly assessing invasion in relevant vessels in cases of pancreatic carcinoma and for determining resectability.

Computed tomography perfusion analysis of pancreatic carcinoma.

Objective The purpose of this study was to evaluate CT perfusion of pancreatic carcinomas using the Patlak model for assessing perfusion, permeability, and blood volume. Methods A total of 25 patients with pancreatic carcinoma were examined prospectively with a 64-slice computed tomography (CT) using a dynamic sequence after intravenous injection of 80-mL contrast material (370 mg/mL; flow rate, 5 mL/s). Eighty-kilovolt (peak) perfusion acquisitions were evaluated for estimating perfusion parameters for carcinoma and healthy tissue using a 2-compartment model (Patlak model). Results Twenty patients had hypodense tumors; in 5 patients, the tumor could not be delineated in contrast-enhanced CT. All carcinomas could be identified clearly in the color-coded perfusion maps. Perfusion, permeability, and blood volume values were significant lower in pancreatic carcinomas compared to healthy pancreatic tissue (0.27 ± 0.20 vs 0.89 ± 0.19 min−1, P < 0.0001; 0.43 ± 0.20 vs 0.75 ± 0.16 × 0.5 min−1, P < 0.0001; and 38.9 ± 20.7 vs 117.8 ± 46.9 mL/100 mL, P < 0.0001). Conclusion Computed tomographic perfusion of the pancreas using a 2-compartment perfusion model is feasible. Color-coded perfusion maps could be a helpful tool to delineate pancreatic carcinomas even if they are not visible in contrast-enhanced CT.

Anaplastic pancreatic cancer: Presentation, surgical management, and outcome.

BACKGROUND Anaplastic pancreatic cancers are rare neoplasms. The available data are focused on pathologic and molecular features, and little is known about the clinical presentation and management. The outcome of operative exploration and resection is unknown. METHODS From a prospective database, all consecutive operations for anaplastic pancreatic cancer performed at our institution were identified. The clinicopathologic details were analyzed and the outcome was compared with a matched group of typical pancreatic ductal adenocarcinomas (nested case-control study). RESULTS Eighteen patients with anaplastic pancreatic cancer were identified. The patients had a median age of 64 years. The tumors were large (median diameter, 4 cm) and showed peripheral contrast enhancement in radiologic imaging. Fifteen (83%) patients underwent resection, a palliative bypass procedure was performed in 1 (6%) patient, and 2 patients underwent exploration with biopsy only. Perioperative morbidity was 39% and mortality was 6%. The median survival rate in patients with anaplastic pancreatic cancer was 5.7 months and was less than in the control group of patients with pancreatic ductal adenocarcinoma (15.7 months). In anaplastic pancreatic cancer, the median duration of survival was significantly greater after R0/R1 resection, as compared with palliative surgery (7.1 vs 2.3 months). The duration of survival was significantly greater in neoplasms with osteoclast-like giant cells. In 3 (17%) patients, long-term survival of 33, 49, and 161 months was observed. CONCLUSION Anaplastic pancreatic cancer is an aggressive type of pancreatic cancer with a short median survival; however, because of the observation of prolonged survival after resection, resection should be performed whenever possible. The presence of osteoclast-like giant cells is associated with a favorable prognosis.

Enhancing pancreatic adenocarcinoma delineation in diffusion derived intravoxel incoherent motion f-maps through automatic vessel and duct segmentation.

Diffusion‐based intravoxel incoherent motion imaging has recently gained interest as a method to detect and characterize pancreatic lesions, especially as it could provide a radiation‐ and contrast agent‐free alternative to existing diagnostic methods. However, tumor delineation on intravoxel incoherent motion‐derived parameter maps is impeded by poor lesion‐to‐pancreatic duct contrast in the f‐maps and poor lesion‐to‐vessel contrast in the D‐maps. The distribution of the diffusion and perfusion parameters within vessels, ducts, and tumors were extracted from a group of 42 patients with pancreatic adenocarcinoma. Clearly separable combinations of f and D were observed, and receiver operating characteristic analysis was used to determine the optimal cutoff values for an automated segmentation of vessels and ducts to improve lesion detection and delineation on the individual intravoxel incoherent motion‐derived maps. Receiver operating characteristic analysis identified f = 0.28 as the cutoff for vessels (Area under the curve (AUC) = 0.901) versus tumor/duct and D = 1.85 μm2/ms for separating duct from tumor tissue (AUC = 0.988). These values were incorporated in an automatic segmentation algorithm and then applied to 42 patients. This yielded clearly improved tumor delineation compared to individual intravoxel incoherent motion‐derived maps. Furthermore, previous findings that indicated that the f value in pancreatic cancer is strongly reduced compared to healthy pancreatic tissue were reconfirmed. Magn Reson Med, 2011.