Imaging in colonic cancer

AbstractWhilst the diagnosis of colonic cancer is always based on visually guided flexible colonoscopy, which is the only technique that provides a histological diagnosis, the pre-treatment assessment of the cancer involves computed tomography. This can determine the exact site of the cancer in the colon, its dimensions and juxta-colonic extension and is used to investigate for liver, mesenteric or lung metastases

Market dynamics associated with credit ratings: a literature review.

Credit ratings produced by the major credit rating agencies (CRAs) aim to measure the creditworthiness, or more specifically the relative creditworthiness of companies, i.e. their ability to meet their debt servicing obligations. In principle, the rating process focuses on the fundamental long-term credit strength of a company. It is typically based on both public and private information, except for unsolicited ratings, which focus only on public information. The basic rationale for using ratings is to achieve information economies of scale and solve principal-agent problems. Partly for the same reasons, the role of credit ratings has expanded significantly over time. Regulators, banks and bondholders, pension fund trustees and other fiduciary agents have increasingly used ratings-based criteria to constrain behaviour. As a result, the influence of the opinions of CRAs on markets appears to have grown considerably in recent years. One aspect of this development is its potential impact on market dynamics (i.e. the timing and path of asset price adjustments, credit spreads, etc.), either directly, as a consequence of the information content of ratings themselves, or indirectly, as a consequence of the “hardwiring” of ratings into regulatory rules, fund management mandates, bond covenants, etc. When considering the impact of ratings and rating changes, two conclusions are worth highlighting. – First, ratings correlate moderately well with observed credit spreads, and rating changes with changes in spreads. However, other factors, such as liquidity, taxation and historical volatility clearly also enter into the determination of spreads. Recent research suggests that reactions to rating changes may also extend beyond the immediately-affected company to its peers, and from bond to equity prices. Furthermore, this price reaction to rating changes seems to be asymmetrical, i.e. more pronounced for downgrades than for upgrades, and may be more significant for equity prices than for bond prices. – Second, the hardwiring of regulatory and market rules, bond covenants, investment guidelines, etc., to ratings may influence market dynamics, and potentially lead to or magnify threshold effects. The more that different market participants adopt identical ratings-linked rules, or are subject to similar ratings-linked regulations, the more “spiky” the reaction to a credit event is likely to be. This reaction may include, in some cases, the emergence of severe liquidity pressures. Efforts have recently been made, notably with support from the rating agencies themselves, to encourage a more systematic disclosure of rating triggers and to renegotiate and smooth the possibly more destabilising forms of rating triggers. However, the lack of a clear disclosure regime makes it difficult to assess how far this process has evolved. Questions also remain as to the extent to which ratings-based criteria introduce a fundamentally new element into market behaviour, or, conversely, the extent to which they are simply a va riant of more traditional contractual covenants. Rating agencies strive to provide credit assessments that remain broadly stable through the course of the business cycle (rating “through the cycle”). Agencies and other analysts frequently contrast the fundamental credit analysis on which ratings are based with market sentiment — measured for example by bond spreads — which is arguably subject to more short-term influences. Agencies are adamant that they do not directly incorporate market sentiment into ratings (although they may use market prices as a diagnostic tool). On the contrary, they make every effort to exclude transient market sentiment. However, as reliance on ratings grows, CRAs are being increasingly expected to satisfy a widening range of constituencies, with different, and even sometimes conflicting, interests: issuers and “traditional” asset managers will look for more than a simple statement of near-term probability of loss, and will stress the need for ratings to exhibit some degree of stability over time. On the other hand, mark-to-market traders, active investors and risk managers may seek more frequent indications of credit changes. Hence, in the wake of major bankruptcies with heightened credit stress, rating agencies have been under considerable pressure to provide higher-frequency readings of credit status, without loss of quality. So far, they have responded to this challenge largely by adding more products to their traditional range, but also through modifications in the rating process. The rating process and the range of products offered by rating agencies have thus evolved over time, with, for instance, an increasing emphasis on the analysis of liquidity risks, a new focus on the hidden liabilities of companies and an increased use of market-based tools. It is too early, however, to judge whether these changes should simply be regarded as a refinement of the agencies’ traditional methodology or whether they suggest a more fundamental shift in the approach to credit risk measurement. For the same reason, it is not possible to draw any firm conclusions about changes in the effects of credit ratings on market dynamics.

Aspects et évaluation post-thérapeutiques des lésions du foie après traitement non chirurgical

The main non-surgical treatments for liver lesions include chemotherapy, targeted treatments, chemoembolization and radiofrequency ablation. The post-treatment imaging features are variable and depend on the initial appearance of the lesion, the type of treatment and the imaging modality. Evaluation of tumour response to treatment is important. RECIST criteria based on unidimensional lesion measurements may not always be appropriate. Other evaluation criteria (Choi for GIST, EASL for HCC or Chun criteria.) may be more relevant

Appendicitis and diverticulitis of the colon: Misleading forms

AbstractAppendicitis and diverticulitis of the colon are the two main causes of febrile acute abdomen in adults. Diagnosis from imaging (ultrasound and CT) is usually easy. However, an imaging procedure which is not suitable for the clinical situation and an examination performed with the wrong protocol are sources of error and must be avoided. Anatomical variants, inflammatory cancers, complicated forms (perforation, secondary occlusion of the small intestine, peripheral abscesses, fistulae, pylephlebitis, liver abscesses) and associated signs related to a peritoneal inflammatory reaction (reflex ileus, reactive ileitis or salpingitis) can also lead to a wrong diagnosis

Early lung ultrasonography predicts the occurrence of acute respiratory distress syndrome in blunt trauma patients

PURPOSE: Extent of lung contusion on initial computed tomography (CT) scan predicts the occurrence of acute respiratory distress syndrome (ARDS) in blunt chest trauma patients. We hypothesized that lung ultrasonography (LUS) on admission could also predict subsequent ARDS. METHODS: Forty-five blunt trauma patients were prospectively studied. Clinical examination, chest radiography, and LUS were performed on arrival at the emergency room. Lung contusion extent was quantified using a LUS score and compared to CT scan measurements. The ability of the LUS score to predict ARDS was tested using the area under the receiver operating characteristic curve (AUC-ROC). The diagnostic accuracy of LUS was compared to that of combined clinical examination and chest radiography for pneumothorax, lung contusion, and hemothorax, with thoracic CT scan as reference. RESULTS: Lung contusion extent assessed by LUS on admission was predictive of the occurrence of ARDS within 72 h (AUC-ROC = 0.78 [95 % CI 0.64-0.92]). The extent of lung contusion on LUS correlated well with CT scan measurements (Spearman\u27s coefficient = 0.82). A LUS score of 6 out of 16 was the best threshold to predict ARDS, with a 58 % [95 % CI 36-77] sensitivity and a 96 % [95 % CI 76-100] specificity. The diagnostic accuracy of LUS was higher than that of combined clinical examination and chest radiography: (AUC-ROC) 0.81 [95 % CI 0.50-1.00] vs. 0.74 [0.48-1.00] (p = 0.24) for pneumothorax, 0.88 [0.76-1.00] vs. 0.69 [0.47-0.92] (p < 0.05) for lung contusion, and 0.84 [0.59-1.00] vs. 0.73 [0.51-0.94] (p < 0.05) for hemothorax. CONCLUSIONS: LUS on admission identifies patients at risk of developing ARDS after blunt trauma. In addition, LUS allows rapid and accurate diagnosis of common traumatic thoracic injuries

Benefit of the Vittel criteria to determine the need for whole body scanning in a severe trauma patient.

OBJECTIVE: To evaluate the use of the Vittel criteria in addition to a clinical examination to determine the need for a whole body scan (WBS) in a severe trauma patient. MATERIALS AND METHODS: Between December 2008 and November 2009, 339 severe trauma patients with at least one Vittel criterion were prospectively evaluated with a WBS. The following data were collected: the Vittel criteria present, circumstances of the accident, traumatic injury on the WBS, and irradiation. The original intent to prescribe a computed tomography (CT) scan (whole body or a targeted region), based solely on clinical signs, was specified. RESULTS: Injuries were diagnosed in 55.75% of the WBS (n=189). The most common Vittel criteria were "global assessment" (n=266), "thrown, run over" (n=116), and "ejected from vehicle" (n=94). The multivariate analysis used the following as independent criteria for predicting severe traumatic injury on the WBS: Glasgow score less than 13, penetrating trauma, and colloid resuscitation greater than 11. Based solely on clinical factors, 164 patients would not have had any scan or (only) a targeted scan. In that case, 15% of the severe injuries would have been missed. CONCLUSION: Using the Vittel criteria to determine the need for a WBS in a severe trauma patient makes it possible to find serious injuries not suspected on the clinical examination, but at the cost of an increased number of normal scans

Portosystemic collateral vessels in liver cirrhosis: a three-dimensional MDCT pictorial review

PURPOSE: Portosystemic collateral vessels (PSCV) are a consequence of the portal hypertension that occurs in chronic liver diseases. Their prognosis is strongly marked by the risk of digestive hemorrhage and hepatic encephalopathy. MATERIALS AND METHODS: CT was performed with a 16-MDCT scanner. Maximum intensity projection and volume rendering were systematically performed on a workstation to analyze PSCV. RESULTS: We describe the PSCV according to their drainage into either the superior or the inferior vena cava. In the superior vena cave group, we found gastric veins, gastric varices, esophageal, and para-esophageal varices. In the inferior vena cava group, the possible PSCV are numerous, with different sub groups: gastro and spleno renal shunts, paraumbilical and abdominal wall veins, retroperitoneal shunts, mesenteric varices, gallbladder varices, and omental collateral vessels. Regarding clinical consequences esophageal and gastric varices are most frequently involved in digestive bleeding; splenorenal shunts often lead to hepatic encephalopathy; the paraumbilical vein is an acceptable derivation pathway for natural decompression of the portal system. CONCLUSION: Knowledge of precise cartography of PSCV is essential to therapeutic decisions. MDCT is the best way to understand and describe the different types of PSCV

Rectal metastasis of prostate cancer: about a case

Prostate adenocarcinomas present a high risk of metastasis. We report a case of an atypical prostate cancer metastasis. A male patient presented a prostatic adenocarcinoma treated by surgery. A biological recurrence was discovered during the follow-up by an increased rate of Prostate Specific Antigen (PSA) and was treated by hormonotherapy. Several months later, there was a re-increase of the PSA rate. The CT scan showed a radiation proctitis aspect. An intermittent hormonotherapy was decided. Six months later, he presented abdominal pain. Examinations were performed and showed a rectal carcinosarcoma with prostate origins. A surgical management was realised. The outcomes were an early recurrence. A symptomatic treatment was decided. There are not any rectal localisations reported in the literature. Only loco-regional invasions of the rectum are described and no histological modification of metastasis compared to the primitive tumor has been reported. So, we report a metastasis of a prostate adenocarcinoma which transformed into a carcinosarcoma. KEYWORDS: Adenocarcinoma; Carcinosarcoma; Metastasis; Prostate; Rectal neoplasm

Factors limiting complete tumor ablation by radiofrequency ablation

The purpose of this study was to determine radiological or physical factors to predict the risk of residual mass or local recurrence of primary and secondary hepatic tumors treated by radiofrequency ablation (RFA). Eighty-two patients, with 146 lesions (80 hepatocellular carcinomas, 66 metastases), were treated by RFA. Morphological parameters of the lesions included size, location, number, ultrasound echogenicity, computed tomography density, and magnetic resonance signal intensity were obtained before and after treatment. Parameters of the generator were recorded during radiofrequency application. The recurrence-free group was statistically compared to the recurrence and residual mass groups on all these parameters. Twenty residual masses were detected. Twenty-nine lesions recurred after a mean follow-up of 18 months. Size was a predictive parameter. Patients\u27 sex and age and the echogenicity and density of lesions were significantly different for the recurrence and residual mass groups compared to the recurrence-free group (p < 0.05). The presence of an enhanced ring on the magnetic resonance control was more frequent in the recurrence and residual mass groups. In the group of patients with residual lesions, analysis of physical parameters showed a significant increase (p < 0.05) in the time necessary for the temperature to rise. In conclusion, this study confirms risk factors of recurrence such as the size of the tumor and emphasizes other factors such as a posttreatment enhanced ring and an increase in the time necessary for the rise in temperature. These factors should be taken into consideration when performing RFA and during follow-up

Sigmoid stricture associated with diverticular disease should be an indication for elective surgery with lymph node clearance

BACKGROUND: The literature concerning stricture secondary to diverticulitis is poor. Stricture in this setting should be an indication for surgery because (a) of the potential risk of cancer and (b) morbidity is not increased compared to other indications for colectomy. The goal of this report is to study the post-surgical morbidity and the quality of life in patients after sigmoidectomy for sigmoid stricture associated with diverticular disease. METHOD: This is a monocenter retrospective observational study including patients with a preoperative diagnosis of sigmoid stricture associated with diverticular disease undergoing operation between Jan 1, 2007 and Dec 31, 2013. The GastroIntestinal Quality of Life Index was used to assess patient satisfaction. RESULTS: Sixteen patients were included of which nine were female. Median age was 69.5 (46-84) and the median body mass index was 23.55kg/m(2) (17.2-28.4). Elective sigmoidectomy was performed in all 16 patients. Overall, complications occurred in five patients (31.2%) (4 minor complications and 1 major complication according to the Dindo and Clavien Classification); none resulted in death. Pathology identified two adenocarcinomas (12.5%). The mean GastroIntestinal Quality of Life Index was 122 (67-144) and 10/11 patients were satisfied with their surgical intervention. CONCLUSION: Sigmoid stricture prevents endoscopic exploration of the entire colon and thus it may prove difficult to rule out a malignancy. Surgery does not impair the quality of life since morbidity is similar to other indications for sigmoidectomy. For these reasons, we recommend that stricture associated with diverticular disease should be an indication for sigmoidectomy including lymph node clearance