Verifying the Magnitude Dependence in Earthquake Occurrence.

The existence of magnitude dependence in earthquake triggering has been reported. Such a correlation is linked to the issue of seismic predictability and it remains under intense debate whether it is physical or is caused by incomplete data due to the missing short-term aftershocks. Working firstly with a synthetic catalog generated by a numerical model that captures most statistical features of earthquakes and then with a high-resolution earthquake catalog for the Amatrice-Norcia (2016) sequence in Italy, where for the latter case we employ the stochastic declustering method to reconstruct the family tree among seismic events and limit our analysis to events above the magnitude of completeness, we found that the hypothesis of magnitude correlation can be rejected.

Estimating generation time of SARS-CoV-2 variants in Italy from the daily incidence rate.

The identification of the transmission parameters of a virus is fundamental to identify the optimal public health strategy. These parameters can present significant changes over time caused by genetic mutations or viral recombination, making their continuous monitoring fundamental. Here we present a method, suitable for this task, which uses as unique information the daily number of reported cases. The method is based on a time since infection model where transmission parameters are obtained by means of an efficient maximization procedure of the likelihood. Applying the method to SARS-CoV-2 data in Italy, we find an average generation time [Formula: see text] days, during the temporal window when the majority of infections can be attributed to the Omicron variants. At the same time we find a significantly larger value [Formula: see text] days, in the temporal window when spreading was dominated by the Delta variant. We are also able to show that the presence of the Omicron variant, characterized by a shorter [Formula: see text], was already detectable in the first weeks of December 2021, in full agreement with results provided by sequences of SARS-CoV-2 genomes reported in national databases. Our results therefore show that the novel approach can indicate the existence of virus variants, resulting particularly useful in situations when information about genomic sequencing is not yet available. At the same time, we find that the standard deviation of the generation time does not significantly change among variants.

The debate on the earthquake magnitude correlations: a meta-analysis.

Among the most important questions that await an answer in seismology, perhaps one is whether there is a correlation between the magnitudes of two successive seismic events. The answer to this question is considered of fundamental importance given the potential effect in forecasting models, such as Epidemic Type Aftershock Sequence models. After a meta-analysis of 29 papers, we speculate that given the lack of studies carried out with realistic physical models and given the possible bias due to the lack of events recorded in the experimental seismic catalogs, important improvements are necessary on both fronts to be sure to provide a statistically relevant answer.

Estimating the generation interval from the incidence rate, the optimal quarantine duration and the efficiency of fast switching periodic protocols for COVID-19.

The transmissibility of an infectious disease is usually quantified in terms of the reproduction number [Formula: see text] representing, at a given time, the average number of secondary cases caused by an infected individual. Recent studies have enlightened the central role played by w(z), the distribution of generation times z, namely the time between successive infections in a transmission chain. In standard approaches this quantity is usually substituted by the distribution of serial intervals, which is obtained by contact tracing after measuring the time between onset of symptoms in successive cases. Unfortunately, this substitution can cause important biases in the estimate of [Formula: see text]. Here we present a novel method which allows us to simultaneously obtain the optimal functional form of w(z) together with the daily evolution of [Formula: see text], over the course of an epidemic. The method uses, as unique information, the daily series of incidence rate and thus overcomes biases present in standard approaches. We apply our method to one year of data from COVID-19 officially reported cases in the 21 Italian regions, since the first confirmed case on February 2020. We find that w(z) has mean value [Formula: see text] days with a standard deviation [Formula: see text] day, for all Italian regions, and these values are stable even if one considers only the first 10 days of data recording. This indicates that an estimate of the most relevant transmission parameters can be already available in the early stage of a pandemic. We use this information to obtain the optimal quarantine duration and to demonstrate that, in the case of COVID-19, post-lockdown mitigation policies, such as fast periodic switching and/or alternating quarantine, can be very efficient.

The influence of the brittle-ductile transition zone on aftershock and foreshock occurrence.

Aftershock occurrence is characterized by scaling behaviors with quite universal exponents. At the same time, deviations from universality have been proposed as a tool to discriminate aftershocks from foreshocks. Here we show that the change in rheological behavior of the crust, from velocity weakening to velocity strengthening, represents a viable mechanism to explain statistical features of both aftershocks and foreshocks. More precisely, we present a model of the seismic fault described as a velocity weakening elastic layer coupled to a velocity strengthening visco-elastic layer. We show that the statistical properties of aftershocks in instrumental catalogs are recovered at a quantitative level, quite independently of the value of model parameters. We also find that large earthquakes are often anticipated by a preparatory phase characterized by the occurrence of foreshocks. Their magnitude distribution is significantly flatter than the aftershock one, in agreement with recent results for forecasting tools based on foreshocks.

Role of the imaging techniques in the diagnosis and staging of hidradenitis suppurativa.

Hidradenitis suppurativa (HS) is a chronic, inflammatory skin disease mainly affecting the axillary, inguinal and anogenital regions, and characterized by the presence of nodules, abscesses and sinus tracts and scarring. Clinical examination alone may underestimate the disease extension and severity. Some non-invasive skin imaging techniques such as ultrasound, magnetic resonance imaging, computed tomography, positron-emission tomography and dermoscopy, have been demonstrated to be useful in the diagnosis and management of HS. They may reveal some findings not appreciable at naked eye evaluation, suggesting the diagnosis in case of minimal/mild presentation or in non-active long-lasting cases and allowing a more accurate staging, treatment planning and monitoring of this debilitating disease.

Acute hemobilia from a pseudoaneurysm of the cystic artery arising from the left hepatic artery: Case report and literature review.

INTRODUCTION: Hemobilia represents only 6% of all causes of upper gastrointestinal bleeding. PRESENTATION OF CASE: We report a rare case of a bleeding pseudoaneurysm of the cystic artery, due to a re-activation of a chronic cholecystitis, which arose with a mixed symptomatology: jaundices and hematemesis. DISCUSSION: The rarity of our patient is increased for some vascular anatomic variations detected by Computed Tomography that influenced the management of the disease. Our patient was treated by endovascular embolization of the pseudoaneurysm and subsequent cholecystectomy. CONCLUSION: About pseudoaneurysm of the cystic artery only few cases have been already reported and to date there are no guidelines for its management. We describe both diagnostic features and therapeutic strategies in comparison to the most recent literature.

Non-Seminomatous Germ Cell Tumor Metastasis to the Jaw: An Imaging Case Report.

Testicular cancer typically spreads to the lymph nodes, but hematogenous dissemination to distant organs can also occur. Bone metastasis is uncommon and is thought to be a poor prognostic indicator. Jaw metastasis is exceedingly rare but is of great clinical significance, since it may be the first sign of an occult testicular cancer or the first evidence of relapse of a known tumor. Herein, we report the first case describing the imaging and clinical findings of a non-seminomatous germ cell tumor with jaw metastasis at diagnosis.

Features and perspectives of MR enterography for pediatric Crohn disease assessment.

The aim of this paper is to provide indications for performing magnetic resonance enterography (MRE) in Crohn's disease (CD), the essential technical elements of MRE techniques and typical findings in patients with CD. Patients suffering from CD frequently require cross-sectional imaging. By performing MRE, it is possible to obtain results comparable to those obtained with endoscopy in terms of identifying and assessing disease activity and better than other cross-sectional imaging techniques, such as CT, in the evaluation of the fibrosis and complications of disease. The MR imaging of diffusion MR is a technique which enables medical staff to add important additional information and which may replace the use of intravenous contrast agents in the near future. Magnetic resonance enterography is an accurate tool for assessing bowel disease and the various complications associated with CD. The lack of exposure to non-ionizing radiation is an important advantage of this imaging technique, especially in the case of pediatric patients. Familiarity with common and pathognomonic imaging features of CD is essential for every clinician involved in the treatment of inflammatory bowel disease and the care of patients.

Extragastrointestinal stromal tumor of lesser omentum: a challenging radiological and histological diagnosis.

Extragastrointestinal stromal tumors (EGISTs) are a rare subgroup of gastrointestinal stromal tumors (GISTs), arising from outside the walls of gastrointestinal tubular organs. We report a case of an EGIST of the lesser omentum that represented a diagnostic challenge. Due to its atypical radiologic findings, it was preoperatively mistaken for pedunculated hepatic hemangioma. Histopathologically, it showed epithelioid structure and c-kit negative, very uncommon for GIST. Only a few cases of EGISTs have been previously reported. We discuss imaging and histological features, emphasizing potential pitfalls.

Congenital portosystemic shunt: our experience.

Introduction. Congenital portosystemic venous malformations are rare abnormalities in which the portal blood drains into a systemic vein and which are characterized by extreme clinical variability. Case Presentations. The authors present two case reports of a congenital extrahepatic portosystemic shunt (Type II). In the first patient, apparently nonspecific symptoms, such as headache and fatigue, proved to be secondary to hypoglycemic episodes related to the presence of a portosystemic shunt, later confirmed on imaging. During portal vein angiography, endovascular embolization of the portocaval fistula achieved occlusion of the anomalous venous tract. In the second patient, affected by Down's syndrome, the diagnosis of a portosystemic malformation was made by routine ultrasonography, performed to rule out concurrent congenital anomalies. Because of the absence of symptoms, we chose to observe this patient. Conclusions. These two case reports demonstrate the clinical heterogeneity of this malformation and the need for a multidisciplinary approach. As part of a proper workup, clinical evaluation must always be followed by radiographic diagnosis.

The utilization of imaging features in the management of intraductal papillary mucinous neoplasms.

Intraductal papillary mucinous neoplasms (IPMNs) represent a group of cystic pancreatic neoplasms with large range of clinical behaviours, ranging from low-grade dysplasia or borderline lesions to invasive carcinomas. They can be grouped into lesions originating from the main pancreatic duct, main duct IPMNs (MD-IPMNs), and lesions which arise from secondary branches of parenchyma, denominated branch-duct IPMNs (BD-IPMNs). Management of these cystic lesions is essentially based on clinical and radiological features. The latter have been very well described in the last fifteen years, with many studies published in literature showing the main radiological features of IPMNs. Currently, the goal of imaging modalities is to identify "high-risk stigmata" or "worrisome feature" in the evaluation of pancreatic cysts. Marked dilatation of the main duct (>1 cm), large size (3-5 cm), and intramural nodules have been associated with increased risk of degeneration. BD-IPMNs could be observed as microcystic or macrocystic in appearance, with or without communication with main duct. Their imaging features are frequently overlapped with cystic neoplasms. The risk of progression for secondary IPMNs is lower, and subsequently an imaging based follow-up is very often proposed for these lesions.

Synchronous occurrence of colon adenocarcinoma and gastric schwannoma: case report and review of the literature.

MATERIAL OF STUDY: We report a case of a 66-year-old man with a gastric schwannoma incidentally discovered during the treatment of a colon cancer. At the pre-operative computed tomography performed for the stadiation of the colonic tumor was incidentally noted the presence of a nodular tumor between the liver and the gastric wall. RESULT: A wedge resection of this gastic tumor and the surgical resection of the left colon were performed all at once. The pathological examination of the gastric neoplasia revealed a picture consistent with gastric schwannoma. DISCUSSION: Gastrointestinal schwannomas are difficult but not impossible to diagnose preoperatively although they are often asymptomatic and radiologic findings are often nonspecific. Radiological features of Gastrointestinal schwannomas described in literature are reviewed. CONCLUSIONS: The treatment of choice is complete surgical excision with free margins because of diagnostic uncertainty, and the long-term outcome is excellent as these lesions are uniformly benign.

A rare pancreatic pseudoaneurysm in patient with acute pancreatitis and multiple myeloma.

The authors report the case of a 78-year old patient affected by multiple myeloma who develops acute pancreatitis and pseudoaneurysmal dilatation of the inferior pancreaticoduodenal artery causing erosion of the second portion of the duodenal wall and hematemesis. The authors focus first on the supposed etiological relationship between multiple myeloma and acute pancreatitis, and they assume that the therapeutic treatment for the bone marrow disease (bortezomib) may have triggered the pancreatic inflammatory response. They then analyze the pathogenesis of the vascular complication which seems to be related to the lytic action of pancreatic enzymes on the vessel wall which results in the formation of a pseudoaneurysm first and a pseudocyst then. The vascular complication was diagnosed by computed tomography (CT) thus avoiding selective angiography which was considered too invasive for the patient. The careful and conservative treatment of the complication has allowed for full healing of the cephalopancreatic region, in addition to avoiding surgery or embolization treatment of the pseudoaneurysm which is accompanied by a mortality rate as high as 50%.

Multidetector computed tomography aspects of tracheal mucosal leishmaniasis localization.

Tracheal mucosal localization of Leishmania is considered a rare and dangerous event. A single case of leishmaniasis of the trachea has been described in literature. Our work describes multidetector computed tomography features of leishmaniasis localized in the tracheal mucosa that occurred in a 68-year-old patient who lived in an endemic zone. Our patient underwent biopsy that established the diagnosis of leishmaniasis.

Liver damage after transarterial chemoembolization without embolizing agent in unresectable hepatocellular carcinoma.

AIM AND BACKGROUND: Transarterial chemoembolization represents a therapy for hepatocellular carcinoma, but in cirrhotic patients affected by large or multifocal HCC with poor hepatic functional reserve, the procedure can damage normal parenchyma. We analyzed the effects on hepatic function of a modified chemoembolization consisting of ethiodized oil (Lipiodol Ultra Fluid) and epirubicin without gelatine sponge (C-LIP). METHODS: Of 90 patients with hepatocellular carcinoma observed from January 1995 to December 1999, 16 with a diagnosis of advanced (large or multifocal) disease underwent 19 C-LIP. The 30th post-C-LIP day was considered as a checkpoint of the biochemical parameters for a possible hepatic failure. The value of alpha-fetoprotein and the clinical finding of ascites were also considered after 30 days. RESULTS: Postoperative values of serum aspartate aminotrasferases, as well as alanine aminotransferase, were significantly higher than preoperative values (P = 0.002 and P = 0.019, respectively) (Table 1). In all patients, there was a significant increase in postoperative total serum bilirubin (P = 0.003). Statistical analysis showed a significant finding of postoperative ascites (P = 0.035) and the effectiveness of C-LIP on neoplastic tissue by a decrease of alpha-fetoprotein values at 30 days (P = 0.067). CONCLUSIONS: Transcatether arterial chemoembolization could represent an effective therapy against multifocal or advanced hepatocellular carcinoma, and its effectiveness is probably not decreased by using a modified procedure without embolizing agent (C-LIP). However, even when performing such a safe procedure, the hepatic functional reserve of the individual patient needs to be accurately evaluated in order to avoid liver failure.

Long-term success of endovascular treatment of benign superior vena cava occlusion with chylothorax and chylopericardium.

The most likely etiology of benign obstruction of the superior vena cava (SVC) include fibrosing mediastinitis and iatrogenic etiologies such as sclerosis and obstruction caused by pacemakers and central venous catheter. Percutaneous stenting of SVC has been used with success both in malignant and benign superior vena cava syndrome; however, long-term follow-up of endovascular procedures is not well known. We present a case of a patient with complete occlusion of SVC of benign etiology, presenting dramatically with bilateral chylothorax and chylopericardium with cardiac tamponade, who underwent successful vena caval revascularization with thrombolytic therapy and placement of self-expanding metallic stent. The 42-month follow-up could encourage endovascular procedures even in SVC syndrome of benign etiology.