Previous studies using dynamic scintigraphy have shown that the measurement of changes in hepatic perfusion may be exploited to detect liver metastases. Similar hepatic haemodynamic changes also occur in cirrhosis, however, thereby reducing the diagnostic power of the technique. The ability of duplex colour Doppler sonography (DCDS) to differentiate between the changes in liver perfusion in patients with cirrhosis and those with hepatic metastases was assessed. Hepatic arterial and portal venous blood flows were measured in 30 control subjects, 20 patients with cirrhosis, and 55 patients with overt liver metastases.The Doppler perfusion index (DPI) (the rate of hepatic arterial to total liver blood flow) and the congestive index (ratio of the cross sectional area of the vessel to time averaged velocity of blood flow in the vessel) of the hepatic artery (HCI) and portal vein (PCI) were calculated. The hepatic arterial blood flow of the cirrhotic and metastatic groups was significantly raised compared with that of controls, and the portal venous blood flow of the former groups were reduced (p<00001). The DPIs of the cirrhotic and metastatic groups were therefore significantly raised compared with those of controls (p<0l0001). No significant difference was noted in HCI values between the three groups. The PCI values of the cirrhotic group, however, were significantly raised compared with those of controls and patients with metastases (p<00001). The data suggest that DCDS measurement of PCI may be of value in differentiating between the hepatic perfusion changes caused by cirrhosis and those resulting from hepatic metastases, thereby increasing the diagnostic power of this technique. (Gut 1993; 34: 554-557) The normal liver receives about 25% of its blood supply via the hepatic artery and the remainder through the portal vein. Parkin et al postulated that the presence of liver tumour might increase the hepatic arterial blood flow, as the blood supply of the tumour is almost exclusively arterial.' using dynamic scintigraphy as an indirect method of measuring blood flow, they calculated the ratio of hepatic arterial to total liver blood flow, the hepatic perfusion index (HPI), and found that it was raised in patients with liver metastases. In this study, we investigated the flow changes associated with hepatic metastases and cirrhosis to assess the value of DCDS in differentiating between the hepatic haemodynamic changes in patients with cirrhosis and those with colorectal liver metastases. MethodsThirty healthy volunteers (age range 23-77 years), 55 patients with histologically proved overt colorectal liver metastases (age range 31-75 years), and 20 patients with cirrhosis (age range 37-70 years) were included in the study. The cirrhosis was caused by alcohol abuse and all these patients had oesophageal varices at endoscopy. The severity of cirrhosis was evaluated according to Child-Pugh's classification. The score of the patients ranged from 2 to 13 with a mean of 7-1.All subjects were examined in the sup...

In this paper, we present an operational system for cyber threat intelligence gathering from various social platforms on the Internet particularly sites on the darknet and deepnet. We focus our attention to collecting information from hacker forum discussions and marketplaces offering products and services focusing on malicious hacking. We have developed an operational system for obtaining information from these sites for the purposes of identifying emerging cyber threats. Currently, this system collects on average 305 high-quality cyber threat warnings each week. These threat warnings include information on newly developed malware and exploits that have not yet been deployed in a cyber-attack. This provides a significant service to cyberdefenders. The system is significantly augmented through the use of various data mining and machine learning techniques. With the use of machine learning models, we are able to recall 92% of products in marketplaces and 80% of discussions on forums relating to malicious hacking with high precision. We perform preliminary analysis on the data collected, demonstrating its application to aid a security expert for better threat analysis.

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Summary Conventional imaging techniques are of limited value in identifying small liver metastases. Indirect methods of measuring blood-flow have shown that metastases may be associated with subtle changes in liver blood-flow. Doppler ultrasonography has the ability to measure liver blood-flow directly. In this study, the role of duplex sonography in the detection of hepatic metastases was evaluated. Hepatic arterial and portal venous blood-flows were In 1983, Parkin and colleagues suggested that changes in liver blood-flow occurring in patients with intra-hepatic tumour could be measured indirectly by dynamic scintigraphy. They described an increase in the ratio of hepatic arterial: total liver blood-flow in patients with overt hepatic metastases. However, this technique has not been widely used in clinical practice because of difficulties in interpretation and reproducibility (Laird et al., 1987).In contrast, duplex sonography has the capacity to measure liver blood-flow directly. In this study, the crosssectional area and velocity of blood-flow within the hepatic artery and portal vein were measured and blood-flow calculated. This technique is less invasive, independent of hepatic function and can be more readily standardised.The aim of this study was to assess the value of duplex sonography in the detection of colorectal liver metastases. StatisticsThe data were analysed using a Mann-Whitney test.

Current imaging modalities are unable to detect small liver metastases because of limited resolution and contrast differentiation. The association between liver metastases and altered liver blood flow has been demonstrated by dynamic scintigraphy, but the clinical feasibility of this test has been questioned. In this study a novel approach to detecting liver metastases was assessed by measurement of liver blood flow using a duplex/color Doppler System. Hepatic arterial and portal venous blood flows were measured in 16 controls, 50 patients with gastrointestinal cancer, and 6 patients with breast cancer. The ratio of hepatic arterial to total liver blood flow (Doppler perfusion index, DPI) and the ratio of hepatic arterial: portal venous blood flow (Doppler flow ratio, DFR) were calculated. The DPI and DFR values of controls and patients with overt liver metastases were clearly separated (p less than 0.0001). The results suggest that duplex/color Doppler ultrasound measurement of hepatic perfusion changes may be of value in the detection of liver metastases.

The important and rapidly emerging new field known as 'cyber threat intelligence' explores the paradigm that defenders of computer networks gain a better understanding of their adversaries by understanding what assets they have available for an attack. In this book, a team of experts examines a new type of cyber threat intelligence from the heart of the malicious hacking underworld - the dark web. These highly secure sites have allowed anonymous communities of malicious hackers to exchange ideas and techniques, and to buy/sell malware and exploits. Aimed at both cybersecurity practitioners and researchers, this book represents a first step toward a better understanding of malicious hacking communities on the dark web and what to do about them. The authors examine real-world darkweb data through a combination of human and automated techniques to gain insight into these communities, describing both methodology and results.

Previous studies have shown that overt intrahepatic tumours are associated with subtle changes in liver perfusion that can be measured directly using duplex colour Doppler sonography (DCDS). This study assessed the predictive value of DCDS in the early detection of occult colorectal hepatic metastases. Hepatic arterial and portal venous blood flow was measured in 50 control subjects and 135 patients with colorectal cancer, 67 with overt liver metastases and 68 with an apparently disease-free liver on the basis of computed tomography and laparotomy findings. The Doppler perfusion index (DPI), defined as the ratio of hepatic arterial to total liver blood flow, was calculated. Clear separation of the DPI values of controls and those of patients with overt metastases was observed (P < 0.0001). Thirty-eight of the 68 patients with a disease-free liver also had an abnormally high DPI value. After 1 year of follow-up, 21 patients with an abnormally high DPI at the time of apparently curative primary resection had developed liver metastases and a further four had died without post-mortem examination. The 30 patients with normal DPI remain disease-free. The data suggest that DPI is of value in the early detection of occult liver metastases.

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