Differentiation between non-hypervascular pancreatic neuroendocrine tumour and pancreatic ductal adenocarcinoma on dynamic computed tomography and non-enhanced magnetic resonance imaging

Purpose: To determine the differentiating features between non-hypervascular pancreatic neuroendocrine tumour (PNET) and pancreatic ductal adenocarcinoma (PDAC) on dynamic computed tomography (CT) and non-enhanced magnetic resonance imaging (MRI). Material and methods: We enrolled 102 patients with non-hypervascular PNET (n = 15) or PDAC (n = 87), who had undergone dynamic CT and non-enhanced MRI. One radiologist evaluated all images, and the results were subjected to univariate and multivariate analyses. To investigate reproducibility, a second radiologist re-evaluated features that were significantly different between PNET and PDAC on multivariate analysis. Results: Tumour margin (well-defined or ill-defined) and enhancement ratio of tumour (ERT) showed significant differences in univariate and multivariate analyses. Multivariate analysis revealed a predominance of well-defined tumour margins in non-hypervascular PNET, with an odds ratio of 168.86 (95% confidence interval [CI]: 10.62-2685.29; p < 0.001). Furthermore, ERT was significantly lower in non-hypervascular PNET than in PDAC, with an odds ratio of 85.80 (95% CI: 2.57-2860.95; p = 0.01). Sensitivity, specificity, and accuracy were 86.7%, 96.6%, and 95.1%, respectively, when the tumour margin was used as the criteria. The values for ERT were 66.7%, 98.9%, and 94.1%, respectively. In reproducibility tests, both tumour margin and ERT showed substantial agreement (margin of tumour, κ = 0.6356; ERT, intraclass correlation coefficients (ICC) = 0.6155). Conclusions: Non-hypervascular PNET showed well-defined margins and lower ERT compared to PDAC, with significant differences. Our results showed that non-hypervascular PNET can be differentiated from PDAC via dynamic CT and non-enhanced MRI

Evaluating the malignant potential of intraductal papillary mucinous neoplasms of the pancreas : added value of non-enhanced endoscopic ultrasound to supplement non-enhanced magnetic resonance imaging

Purpose: To evaluate the diagnostic performance of combining non-enhanced magnetic resonance imaging (MRI) and non-enhanced endoscopic ultrasonography (EUS) for assessing the malignant potential of lesions in patients with intraductal papillary mucinous neoplasms of the pancreas (IPMNs). Material and methods: Data from 38 patients histopathologically diagnosed with IPMN adenomas or IPMN adenocarcinomas were retrospectively analysed. Preliminary univariate and multivariate analyses were conducted to identify statistically significant associations. Three blinded radiologists evaluated the image sets to assess the diagnostic performance of combined use of non-enhanced MRI and EUS as opposed to non-enhanced MRI alone in distinguishing malignant from benign lesions. Observer performance and interobserver variability were determined using receiver-operating-characteristic curve analysis and weighted κ statistics. Results: Multivariate analyses identified a significant difference between the abrupt change in the main pancreatic duct (MPD) calibre with distal pancreatic atrophy and the signal intensity of lesion-to-spinal cord ratio on MRI; a significant difference was observed in MPD size on EUS. Diagnostic performance assessments of the image sets did not differ significantly between the blinded radiologists. Conclusions: The clinical utility of non-enhanced EUS may be attributive in evaluating IPMN that has already been evaluated by non-enhanced MRI

3D quantitative analysis of diffusion-weighted imaging for predicting the malignant potential of intraductal papillary mucinous neoplasms of the pancreas

Purpose: To investigate the predictors of intraductal papillary mucinous neoplasms of the pancreas (IPMNs) with high-grade dysplasia, using 2-dimensional (2D) analysis and 3-dimensional (3D) volume-of-interest-based apparent diffusion coefficient (ADC) histogram analysis. Material and methods: The data of 45 patients with histopathologically confirmed IPMNs with high-grade or lowgrade dysplasia were retrospectively assessed. The 2D analysis included lesion-to-spinal cord signal intensity ratio (LSR), minimum ADC value ($ADC_{min}$), and mean ADC value ($ADC_{mean}$). The 3D analysis included the overall mean ($ADC_{overall mean}$), mean of the bottom 10th percentile ($ADC_{mean0-10}$), mean of the bottom 10-25th percentile ($ADC_{mean10-25}$), mean of the bottom 25-50th percentile ($ADC_{mean25-50}$), skewness ($ADC_{skewness}$), kurtosis ($ADC_{kurtosis}$), and entropy ($ADC_{entropy}$). Diagnostic performance was compared by analysing the area under the receiver operating characteristic curve (AUC). Inter-rater reliability was assessed by blinded evaluation using the intraclass correlation coefficient. Results: There were 16 and 29 IPMNs with high- and low-grade dysplasia, respectively. The LSR, $ADC_{overall mean}$, $ADC_{mean0-10}$, $ADC_{mean10-25}$, $ADC_{mean25-50}$, and $ADC_{entropy}$ showed significant between-group differences (AUC = 72-93%; p < 0.05). Inter-rater reliability assessment showed almost perfect agreement for LSR and substantial agreement for $ADC_{overall mean}$ and $ADC_{entropy}$. Multivariate logistic regression showed that $ADC_{overall mean}$ and $ADC_{entropy}$ were significant independent predictors of malignancy (p < 0.05), with diagnostic accuracies of 80% and 73%, respectively. Conclusion: $ADC_{overall mean}$ and $ADC_{entropy}$ from 3D analysis may assist in predicting IPMNs with high-grade dysplasia

Acute enlargement and subsequent rupture of an abdominal aortic aneurysm in a patient receiving chemotherapy for pancreatic carcinoma

AbstractWe report a case of ruptured abdominal aortic aneurysm (AAA) in a patient receiving chemotherapy for pancreatic cancer. We reviewed the literature on the effects of corticosteroids and chemotherapy on aaa formation and discuss possible mechanisms for drug action to promote aneurysm expansion and rupture. If cancer and AAA coincide and curative chemotherapy is possible, a potential impact of chemotherapy on AAA expansion should be considered. (J Vasc Surg 2000;32:197-200.

Is elevated creatinine level a contraindication to endovascular aneurysm repair?

AbstractPurposeIt is widely believed that chronic renal insufficiency (CRI) greatly increases the risk associated with endovascular abdominal aortic aneurysm repair (EVAR) and is a relative contraindication to the procedure and to the use of intra-arterial contrast agents (IACA). We reviewed a 5-year EVAR experience to determine whether the procedure and use of IACA have an important deleterious effect on renal function in patients with and without pre-existing CRI.MethodsEndovascular aneurysm repair (EVAR) was performed in 200 patients with a variety of endografts, with intra-arterial contrast agents. The patients were retrospectively assigned to three groups on the basis of preoperative serum creatinine concentration (Cr): group 1 (n = 108), Cr less than 1.5 mg/dL (normal range); group 2 (n = 65), Cr 1.5 to 2.0 mg/dL; group 3 (n = 27), Cr 2.1 to 3.5 mg/dL. No patients had undergone hemodialysis. In groups 2 and 3, patients received hydration perioperatively, and received mannitol intraoperatively; no nephrotoxic drugs were administered during the procedure, other than nonionic contrast agent (Omnipaque 350).ResultsThe incidence of postoperative complications between the three study groups was not statistically different. In group 1 a transient increase in serum Cr (>30% over baseline and >1.4 mg/dL) was noted in three patients (2.7%), two of whom (1.9%) required temporary hemodialysis and one (0.9%) who died of renal failure. In group 2 a transient increase in serum Cr was noted in two patients (3.1%); both patients (3.1%) required temporary hemodialysis, and one patient (1.5%) died of renal failure. In group 3 a transient increase in serum Cr was noted in two patients (7.4%); one patient (3.7%) required temporary hemodialysis, and one patient (3.7%) died of renal failure. Perioperative hypotension significantly increased the risk for elevated serum Cr and death (P < .05), and larger contrast volume was associated with an increase in serum Cr (P < .05) during the postoperative period.ConclusionsEVAR with intra-arterial contrast agents can be accomplished in patients with chronic renal insufficiency who do not require dialysis, with limited and acceptable morbidity and mortality, similar to that observed with open aneurysm repair. Contrary to other reports in which perioperative precautions were not used, our study shows that with EVAR the risk for worsening renal failure, dialysis, and death is only slightly, and not significantly, greater in patients with preoperative chronic renal insufficiency compared with patients with normal renal function. Perioperative hypotension and increased contrast volume are significant risk factors for postoperative increase in serum Cr and death. With appropriate precautions such as averting perioperative hypotension and limiting the volume of nonionic contrast agents, elevated Cr need not be a contraindication to EVAR with intra-arterial contrast agents

Endoleaks after endovascular graft treatment of aortic aneurysms: Classification, risk factors, and outcome

AbstractPurpose: Incomplete endovascular graft exclusion of an abdominal aortic aneurysm results in an endoleak. To better understand the pathogenesis, significance, and fate of endoleaks, we analyzed our experience with endovascular aneurysm repair. Methods:Between November 1992 and May 1997, 47 aneurysms were treated. In a phase I study, patients received either an endovascular aortoaortic graft (11) or an aortoiliac, femorofemoral graft (8). In phase II, procedures and grafts were modified to include aortofemoral, femorofemoral grafts (28) that were inserted with juxtarenal proximal stents, sutured endovascular distal anastomoses within the femoral artery, and hypogastric artery coil embolization. Endoleaks were detected by arteriogram, computed tomographic scan, or duplex ultrasound. Classification systems to describe anatomic, chronologic, and physiologic endoleak features were developed, and aortic characteristics were correlated with endoleak incidence. Results: Endoleaks were discovered in 11 phase I patients (58%) and only six phase II patients (21%; p < 0.05). Aneurysm neck lengths 2 cm or less increased the incidence of endoleaks (p < 0.05). Although not significant, aneurysms with patent side branches or severe neck calcification had a higher rate of endoleaks than those without these features (47% vs 29% and 57% vs 33%, respectively), and patients with iliac artery occlusive disease had a lower rate of endoleaks than those without occlusive disease (18% vs 42%). Endoleak classifications revealed that most endoleaks were immediate, without outflow, and persistent (71% each), proximal (59%), and had aortic inflow (88%). One patient with a persistent endoleak had aneurysm rupture and died. Conclusions: Endoleaks complicate a significant number of endovascular abdominal aortic aneurysm repairs and may permit aneurysm growth and rupture. The type of graft used, the technique of graft insertion, and aortic anatomic features all affect the rate of endoleaks. Anatomic, chronologic, and physiologic classifications can facilitate endoleak reporting and improve understanding of their pathogenesis, significance, and fate. (J Vasc Surg 1998;27:69-80.

Two-Photon Imaging of Calcium in Virally Transfected Striate Cortical Neurons of Behaving Monkey

Two-photon scanning microscopy has advanced our understanding of neural signaling in non-mammalian species and mammals. Various developments are needed to perform two-photon scanning microscopy over prolonged periods in non-human primates performing a behavioral task. In striate cortex in two macaque monkeys, cortical neurons were transfected with a genetically encoded fluorescent calcium sensor, memTNXL, using AAV1 as a viral vector. By constructing an extremely rigid and stable apparatus holding both the two-photon scanning microscope and the monkey's head, single neurons were imaged at high magnification for prolonged periods with minimal motion artifacts for up to ten months. Structural images of single neurons were obtained at high magnification. Changes in calcium during visual stimulation were measured as the monkeys performed a fixation task. Overall, functional responses and orientation tuning curves were obtained in 18.8% of the 234 labeled and imaged neurons. This demonstrated that the two-photon scanning microscopy can be successfully obtained in behaving primates

Reviving surgery with the smile, excitement, and Gemeinschaft concept: attempt at the Department of Surgery, Jikei University

Between 1994 and 2004, the number of surgeons in Japan declined by 18%, whereas the total number of medical doctors increased by 30% during the same period. This was due to the fact that the younger generation avoided tough working environments with long working hours. We attempted to revive surgery by reintroducing the good old Japanese community as the model under the slogan of “intimate community with excitement and sense of secureness”. In the absence of financial incentives, we were able to recruit young staff, and the number of surgeons at Jikei University has increased by 28% over the last 12 years and currently we have 280 surgeons. Our experience showed that although the younger generation is conscious about quality of life and financial success, they also value excitement, friendship, and happiness, something we were able to provide without financial spending. However, our success may be an exception and cannot be generalized; therefore, we should continue to strive to improve the surgeon’s quality of life by creating a better working environment, including sustainable work hours and decent financial incentives