Reports on progress in physics the complex dynamics of earthquake fault systems: new approaches to forecasting and nowcasting of earthquakes.

Charles Richter's observation that 'only fools and charlatans predict earthquakes,' reflects the fact that despite more than 100 years of effort, seismologists remain unable to do so with reliable and accurate results. Meaningful prediction involves specifying the location, time, and size of an earthquake before it occurs to greater precision than expected purely by chance from the known statistics of earthquakes in an area. In this context, 'forecasting' implies a prediction with a specification of a probability of the time, location, and magnitude. Two general approaches have been used. In one, the rate of motion accumulating across faults and the amount of slip in past earthquakes is used to infer where and when future earthquakes will occur and the shaking that would be expected. Because the intervals between earthquakes are highly variable, these long-term forecasts are accurate to no better than a hundred years. They are thus valuable for earthquake hazard mitigation, given the long lives of structures, but have clear limitations. The second approach is to identify potentially observable changes in the Earth that precede earthquakes. Various precursors have been suggested, and may have been real in certain cases, but none have yet proved to be a general feature preceding all earthquakes or to stand out convincingly from the normal variability of the Earth's behavior. However, new types of data, models, and computational power may provide avenues for progress using machine learning that were not previously available. At present, it is unclear whether deterministic earthquake prediction is possible. The frustrations of this search have led to the observation that (echoing Yogi Berra) 'it is difficult to predict earthquakes, especially before they happen.' However, because success would be of enormous societal benefit, the search for methods of earthquake prediction and forecasting will likely continue. In this review, we note that the focus is on anticipating the earthquake rupture before it occurs, rather than characterizing it rapidly just after it occurs. The latter is the domain of earthquake early warning, which we do not treat in detail here, although we include a short discussion in the machine learning section at the end.

Combined cut down and endovascular retrieval of orphaned ventriculoatrial shunt with stenting of chronic superior vena cava occlusion.

Revascularization of the superior vena cava (SVC) in the context of symptomatic luminal obstruction is a therapeutic intervention performed for SVC syndrome of benign or malignant etiology. Venous occlusion can preclude future access and cause symptoms ranging from mild chest discomfort to the more serious effects of SVC syndrome. This case report demonstrates the treatment of a novel case of SVC syndrome arising from a previously placed SVC stent. An intravascular, extraluminal orphaned ventriculoatrial shunt was used to go through the SVC but around the existing lumen-limiting stent to place a new larger stent for revascularization. This case highlights the need for an innovative approach for complex foreign body retrieval and treatment of chronic SVC occlusion.

Long aftershock sequences within continents and implications for earthquake hazard assessment.

One of the most powerful features of plate tectonics is that the known plate motions give insight into both the locations and average recurrence interval of future large earthquakes on plate boundaries. Plate tectonics gives no insight, however, into where and when earthquakes will occur within plates, because the interiors of ideal plates should not deform. As a result, within plate interiors, assessments of earthquake hazards rely heavily on the assumption that the locations of small earthquakes shown by the short historical record reflect continuing deformation that will cause future large earthquakes. Here, however, we show that many of these recent earthquakes are probably aftershocks of large earthquakes that occurred hundreds of years ago. We present a simple model predicting that the length of aftershock sequences varies inversely with the rate at which faults are loaded. Aftershock sequences within the slowly deforming continents are predicted to be significantly longer than the decade typically observed at rapidly loaded plate boundaries. These predictions are in accord with observations. So the common practice of treating continental earthquakes as steady-state seismicity overestimates the hazard in presently active areas and underestimates it elsewhere.

Why do seismic hazard models worldwide appear to overpredict historical intensity observations?

Probabilistic seismic hazard assessments (PSHAs) provide the scientific basis for building codes to reduce damage from earthquakes. Despite their substantial impact, little is known about how well PSHA predicts actual shaking. Recent PSHA for California, Japan, Italy, Nepal, and France appear to consistently overpredict historically observed earthquake shaking intensities. Numerical simulations show that observed shaking is equally likely to be above or below predictions. This result from independently developed models and datasets in different countries and tectonic settings indicates possible systematic bias in the hazard models, the observations, or both. Analysis of possible causes shows that much of the discrepancy is due to a subtle and rarely considered issue: the conversion equations used in comparing the models-which forecast shaking as peak ground acceleration or velocity-and observations-parameterizations of qualitative shaking reports. Historical shaking reports fill a crucial data gap, but more research is warranted on how qualitative observations relate to instrumental shaking measures for earthquakes.

Seismology: speed and size of the Sumatra earthquake.

Our seismological results reveal that Indonesia's devastating Sumatra-Andaman earthquake on 26 December 2004 was 2.5 times larger than initial reports suggested--second only to the 1960 Chilean earthquake in recorded magnitude. They indicate that it slowly released its energy by slip along a 1,200-km fault, generating a long rupture that contributed to the subsequent tsunami. Now that the entire rupture zone has slipped, the strain accumulated from the subduction of the Indian plate beneath the Burma microplate has been released, and there is no immediate danger of a similar tsunami being generated on this part of the plate boundary, although large earthquakes on segments to the south still present a threat.

Conventional Hepatic Volumetry May Lead to Inaccurate Segmental Yttrium-90 Radiation Dosimetry.

OBJECTIVE: To compare radioembolization treatment zone volumes from mapping cone beam CT (CBCT) versus planning CT/MRI and to model their impact on dosimetry. METHODS: Y90 cases were retrospectively identified in which intra-procedural CBCT angiograms were performed. Segmental and lobar treatment zone volumes were calculated with semi-automated contouring using Couinaud venous anatomy (planning CT/MRI) or tumor angiosome enhancement (CBCT). Differences were compared with a Wilcoxon signed-rank test. Treatment zone-specific differences in segmental volumes by volumetric method were also calculated and used to model differences in delivered dose using medical internal radiation dosimetry (MIRD) at 200 and 120 Gy targets. Anatomic, pathologic, and technical factors likely affecting segmental volumes by volumetric method were evaluated. RESULTS: Forty segmental and 48 lobar CBCT angiograms and corresponding planning CT/MRI scans were included. Median Couinaud- and CBCT-derived segmental volumes were 281 and 243 mL, respectively (p = 0.005). Differences between Couinaud and CBCT lobar volumes (right, left) were not significant (p = 0.24, p = 0.07). Couinaud overestimated segmental volumes in 28 cases by a median of 98 mL (83%) and underestimated in 12 cases by median 69 mL (20%). At a 200 Gy dose target, Couinaud estimates produced median delivered doses of 367 and 160 Gy in these 28 and 12 cases. At a 120 Gy target, Couinaud produced doses of 220 and 96 Gy. Proximal vs. distal microcatheter positioning, variant arterial anatomy, and tumor location on or near segmental watersheds were leading factors linked to volumetric differences. CONCLUSION: Use of CBCT-based volumetry may allow more accurate, personalized dosimetry for segmental Y90 radioembolization.

The economics of quality and safety in radiology: Accreditation programs and landmark legislation.

Quality and patient safety are essential to the practice of radiology. "Quality is our image" is the slogan for the American College of Radiology (ACR), which has embraced the quality and safety movement as a central tenet. The impact of advances in radiology on diagnosis and management of complex medical disorders cannot be understated. Nevertheless, these revolutionary technologies do come at a cost. Increasing utilization of advanced imaging in emergency departments throughout the country poses challenges both in terms of appropriate use and management of radiation dose. The indispensable place advanced imaging plays in diagnosis has necessitated guidelines and accountability to protect patients and radiology staff. In this series, we have created a concise discourse on what we have determined to be the essentials of the economics of quality and safety as it pertains to radiology. In this first article, we summarize the accreditation programs in radiology, their legislative background, and the associated financial and market responses that have subsequently resulted. We discuss the progression from historical predecessors to the passage of the Mammography Quality and Safety Act (MQSA), which served as a model for subsequent laws governing the quality and safety of other imaging modalities. These laws have had real economic implications for radiology practices seeking to meet new increasingly stringent guidelines. We also break down the costs of participation in the ACR accreditation and center of excellence programs.

Interventional radiology's role in the diagnosis and management of patients with gallbladder carcinoma.

Gallbladder carcinoma is a rare, aggressive biliary tract malignancy, with a 5-year survival of less than 5%. It is the 6th most common gastrointestinal malignancy in the United States and more commonly found in women. While some risk factors include gallstones, porcelain gallbladder, and smoking, gallbladder carcinoma is often found incidentally following cholecystectomy or percutaneous image guided biopsy. Patients frequently present in a late disease state when they are no longer surgical candidates and minimally invasive image guided-interventions therefore play a critical role in the management and treatment of these patients. This review will discuss some of the key procedures and roles interventional radiologists play in the diagnosis and management of patients suffering from gallbladder carcinoma including tissue sampling, placement of intra-arterial infusion pumps, preoperative portal vein embolization (PVE), biliary drainage, management of post-operative complications such as bile leaks or biliary obstruction, and management of chronic pain.

Insights into earthquake hazard map performance from shaking history simulations.

Why recent large earthquakes caused shaking stronger than shown on earthquake hazard maps for common return periods is under debate. Explanations include: (1) Current probabilistic seismic hazard analysis (PSHA) is deficient. (2) PSHA is fine but some map parameters are wrong. (3) Low-probability events consistent with a map sometimes occur. This issue has two parts. Verification involves how well maps implement PSHA ("have we built the map right?"). Validation asks how well maps forecast shaking ("have we built the right map?"). We explore how well a map can ideally perform by simulating an area's shaking history and comparing "observed" shaking to that predicted by a map generated for the same parameters. The simulations yield shaking distributions whose mean is consistent with the map, but individual shaking histories show large scatter. Infrequent large earthquakes cause shaking much stronger than mapped, as observed. Hence, PSHA seems internally consistent and can be regarded as verified. Validation is harder because an earthquake history can yield shaking higher or lower than the hazard map without being inconsistent. As reality gives only one history, it is hard to assess whether misfit between a map and actual shaking reflects chance or a map biased by inappropriate parameters.

Micropapillary and/or Solid Histologic Subtype Based on Pre-Treatment Biopsy Predicts Local Recurrence After Thermal Ablation of Lung Adenocarcinoma.

BACKGROUND: To investigate whether histologic subtyping from biopsies can predict local recurrence after thermal ablation for lung adenocarcinoma. METHODS: Patients treated with CT-guided thermal ablation for lung adenocarcinoma that had pre-ablation needle biopsy with analysis of histologic components were identified. Age, gender, smoking status, treatment indication (primary stage 1 tumor versus salvage), histologic subtype, ground-glass radiographic appearance, tumor size, ablation modality, and ablation margin were evaluated in relation to time to local recurrence (TTLR). Cumulative incidence of recurrence (CIR) was calculated using competing risks analysis and compared across groups using Fine and Grey method with clustering. Multivariate analysis was conducted with stepwise regression. RESULTS: There were 53 patients with 57 tumors diagnosed as adenocarcinoma on pre-ablation biopsy and with histologic subtype analysis. Of these, 19% (11) had micropapillary components, 14% (8) had solid components, and 26% (15) had micropapillary and/or solid components. In the univariate analysis, solid (subdistribution hazard ratio [SHR] = 4.04, p = 0.0051, 95% confidence interval [CI] = 1.52-10.7), micropapillary (SHR = 3.36, p = 0.01, CI = 1.33-8.47), and micropapillary and/or solid components (SHR = 5.85, p = 0.00038, CI = 2.21-15.5) were significantly correlated with shorter TTLR. On multivariate analysis, the presence of micropapillary and/or solid component (SHR = 11.4, p = 0.00021, CI: 3.14-41.3) was the only independent predictor of TTLR. The 1-, 2-, and 3-year CIR in patients with micropapillary and/or solid components was 33, 49, and 66% compared to 5, 14, and 18% in patients with no micropapillary or solid components on biopsy specimens. CONCLUSION: Micropapillary and/or solid histologic components identified in pre-ablation biopsy are associated with shorter TTLR after thermal ablation of lung adenocarcinoma.

Are chargemaster rates for imaging studies lower in States that cap noneconomic damages (tort reform)?

PURPOSE: To determine whether chargemaster (a list of prices for common services and procedures set by individual hospitals) rates for diagnostic imaging were lower in states that cap awards for noneconomic damages (NED) than states with unlimited awards for medical negligence. METHODS: We analyzed 2011 chargemaster data from the Centers for Medicare & Medicaid, pertaining to 6 ambulatory patient classifications specific to imaging. The dataset includes outpatient imaging facilities and hospitals in 49 states and the District of Columbia. The association between caps on NED and chargemaster rates for imaging in a sample of 15,218 data points was analyzed using linear regression and two-sample t tests assuming unequal variances. RESULTS: In states that cap NED, the chargemaster rates were higher for the following modalities: Level II Echocardiogram without Contrast (mean charges: $2,015.60 versus $1,884.81, P = .0018); Level II Cardiac Imaging ($4,670.25 versus $4,398.58, P = .002); MRI & Magnetic Resonance Angiography without Contrast ($2,654.31 versus $2,526.74, P = .002); and Level III Diagnostic and Screening Ultrasound ($1,073.31 versus $1,027.32, P = .037). High charge-to-payment ratios were associated with states with the highest charges. There was a positive correlation between number of outpatient centers in the state and the average chargemaster rates for the state (mean chargemaster rate = 1727 + 0.79*Number of Outpatient Centers; R-squared = 0.23, P = .0004). CONCLUSIONS: Chargemaster rates for select imaging services are not lower in states that have capped NED.

Chromium Therapy for Insulin Resistance Associated with HIV-Disease.

OBJECTIVE: With the advent of highly active anti-retroviral therapy, HIV disease has become a chronic condition, but with a number of metabolic complications including insulin resistance and diabetes mellitus, dyslipidemia and hypertension and an increased incidence of atherosclerosis. The aim of the current study was to test the safety and efficacy of chromium picolinate for HIV- associated insulin resistance. MATERIALS/METHODS: The study was a randomized, double-blind, placebo-controlled trial with subjects receiving 500µg of chromium picolinate or placebo twice daily for two months. HIV- infected subjects were selected based on a fasting concentration of plasma glucose greater than 5.5mmol/L or a plasma glucose concentration of greater than 7.7mmol/L (but less than 11mmol/L) 2h after oral ingestion of 75g of glucose. Insulin sensitivity was assessed with a hyper-insulinemic-euglycemic clamp and glucose tolerance was assessed with the oral glucose tolerance test. Subjects were monitored closely for alterations in viral load, CD4+ cells, hemoglobin and hematocrit, kidney and liver function, and fasting lipid profiles. RESULTS: Forty-three subjects were enrolled and 39 completed the protocol (20 in the chromium-supplemented and 19 in the placebo arm). Following chromium-supplementation, there were no significant changes in either insulin sensitivity or glucose tolerance. There was a significant improvement in serum HDL cholesterol concentration in the group supplemented with chromium. CONCLUSIONS: Chromium picolinate supplementation at this level was well-tolerated, but overall was not an effective therapy for insulin resistance in these HIV-infected subjects.

Time-variable deformation in the New Madrid seismic zone.

New geodetic measurements show that the New Madrid is currently deforming too slowly, if at all, to account for large earthquakes in the region over the past 5000 years. This result, together with increasing evidence for temporal clustering and spatial migration of earthquake sequences in continental interiors, indicates that either tectonic loading rates or fault properties vary over a few thousand years.