Advances in Myocardial Perfusion MR Imaging: Physiological Implications,the Importance of Quantitative Analysis,and Impact on Patient Care in Coronary Artery Disease

Stress myocardial perfusion imaging (MPI) is the preferred test in patients with intermediate-to-high clinical likelihood of coronary artery disease (CAD) and can be used as a gatekeeper to avoid unnecessary revascularization. Cardiac magnetic resonance (CMR) has a number of favorable characteristics, including: (1) high spatial resolution that can delineate subendocardial ischemia; (2) comprehensive assessment of morphology, global and regional cardiac functions, tissue characterization, and coronary artery stenosis; and (3) no radiation exposure to patients. According to meta-analysis studies, the diagnostic accuracy of perfusion CMR is comparable to positron emission tomography (PET) and perfusion CT, and is better than single-photon emission CT (SPECT) when fractional flow reserve (FFR) is used as a reference standard. In addition, stress CMR has an excellent prognostic value. One meta-analysis study demonstrated the annual event rate of cardiovascular death or non-fatal myocardial infarction was 4.9% and 0.8%, respectively, in patients with positive and negative stress CMR. Quantitative assessment of perfusion CMR not only allows the objective evaluation of regional ischemia but also provides insights into the pathophysiology of microvascular disease and diffuse subclinical atherosclerosis. For accurate quantification of myocardial perfusion, saturation correction of arterial input function is important. There are two major approaches for saturation correction, one is a dual-bolus method and the other is a dual-sequence method. Absolute quantitative mapping with myocardial perfusion CMR has good accuracy in detecting coronary microvascular dysfunction. Flow measurement in the coronary sinus (CS) with phase contrast cine CMR is an alternative approach to quantify global coronary flow reserve (CFR). The measurement of global CFR by quantitative analysis of perfusion CMR or flow measurement in the CS permits assessment of microvascular disease and diffuse subclinical atherosclerosis, which may provide improved prediction of future event risk in patients with suspected or known CAD. Multi-institutional studies to validate the diagnostic and prognostic values of quantitative perfusion CMR approaches are required.     

Out-Of-Pocket Expenditure Associated with Physical Inactivity,Excessive Weight,and Obesity in China: Quantile Regression Approach

IntroductionPrevious studies exploring associations of physical inactivity, obesity, and out-of-pocket expenditure (OOPE) mainly used traditional linear regression, and little is known about the effect of both physical inactivity and obesity on OOPE across the percentile distribution. This study aims to assess the effects of physical inactivity and obesity on OOPE in China using a quantile regression approach.MethodsStudy participants included 10,687 respondents aged 45 years and older from the recent wave of the China Health and Retirement Longitudinal Study in 2015. Linear regression and quantile regression models were used to examine the association of physical activity, body weight with annual OOPE.ResultsOverall, the proportion of overweight and obesity was 33.2% and 5.8%, respectively. The proportion of individuals performing high-level, moderate-level, and low-level physical activity was 55.2%, 12.7%, and 32.1%, respectively. The effects of low-level physical activity on annual OOPE were small at the bottom quantiles but more pronounced at higher quantiles. Respondents with low-level activity had an increased annual OOPE of 26.9 USD, 150.3 USD, and 1,534.4 USD, at the 10th, 50th, and 90th percentiles, respectively, compared with those with high-level activity. The effects of overweight and obesity on OOPE were also small at the bottom quantiles but more pronounced at higher quantiles.ConclusionInterventions that improve the lifestyles and unhealthy behaviors among people with obesity and physical inactivity are likely to yield substantial financial gains for the individual and health systems in China.     

Necrotizing Bacillus cereus infection of the meninges without inflammatory reaction in a patient with acute myelogenous leukemia: a case report

A 64-year-old man in a severely immunocompromised state due to acute myelogenous leukemia died, respirator-unaided, about 10 h after the abrupt onset of coma. An earlier blood culture had yielded Bacillus cereus. The autopsy, performed 2 h after death, demonstrated diffuse subarachnoid hemorrhage without berry aneurysms, and the formalin-fixed brain was tinged with gray-brownish discoloration. The sections of the brain presented a whitish tint of the surface layer of all portion of the cerebral cortices, even those in the sulci. Histological examination of the brain revealed leptomeningeal B. cereus dissemination, and widespread necrosis of the leptomeninges and arachnoid vessels without inflammatory cell reaction. The grossly recognizable whitish surface layer of the cerebral cortex showed overt hyperchromatism, and contained neurons more degenerative than those located in the deeper cortical layer. The total absence of inflammatory reaction may be explained by a combination of the immunocompromised state of the patient and the character of B. cereus infection, which in itself induces little inflammatory reaction. The prominent lesions were confined to the cerebral surface layer and leptomeningeal tissue including the arachnoid vessels, which were all bathed in the cerebrospinal fluid, suggesting that some necrotizing toxins had been secreted into the fluid by the B. cereus. The necrosis of arachnoid vessels is thought to have in turn caused diffuse subarachnoid hemorrhage and marked disturbance of the cerebral blood flow, resulting in the terminal coma. Received: 4 April 1996 / Revised, accepted: 8 September 1996     

Voxel‐wise quantification of myocardial perfusion by cardiac magnetic resonance. Feasibility and methods comparison

The purpose of this study is to enable high spatial resolution voxel‐wise quantitative analysis of myocardial perfusion in dynamic contrast‐enhanced cardiovascular MR, in particular by finding the most favorable quantification algorithm in this context. Four deconvolution algorithms—Fermi function modeling, deconvolution using B‐spline basis, deconvolution using exponential basis, and autoregressive moving average modeling —were tested to calculate voxel‐wise perfusion estimates. The algorithms were developed on synthetic data and validated against a true gold‐standard using a hardware perfusion phantom. The accuracy of each method was assessed for different levels of spatial averaging and perfusion rate. Finally, voxel‐wise analysis was used to generate high resolution perfusion maps on real data acquired from five patients with suspected coronary artery disease and two healthy volunteers. On both synthetic and perfusion phantom data, the B‐spline method had the highest error in estimation of myocardial blood flow. The autoregressive moving average modeling and exponential methods gave accurate estimates of myocardial blood flow. The Fermi model was the most robust method to noise. Both simulations and maps in the patients and hardware phantom showed that voxel‐wise quantification of myocardium perfusion is feasible and can be used to detect abnormal regions. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.     

Midterm results of stent-graft repair of acute and chronic aortic dissection with descending tear: the complication-specific approach

BACKGROUND: Endovascular stent-graft placement for the treatment of patients with aortic dissection is emerging as an attractive alternative to conventional cardiac operations. However, there has been no report of longer-term follow-up. The purpose of this study is to describe our midterm results with endovascular stent-graft repair for the treatment of patients with aortic dissections. METHODS: Thirty-eight patients with aortic dissections with descending tears were treated with endovascular stent-grafting. Ten patients had acute type A, 14 patients had acute type B, and 14 patients had chronic type B dissection. Stent grafts fabricated from expanded polytetrafluoroethylene-covered Z stents were placed to close entry tears in all patients through the delivery systems introduced from the femoral or the iliac arteries. RESULTS: Two patients with complicated acute type B dissection, who would have required surgical intervention, died within 30 days of the procedure, although no other patients died within the same period. There were no late deaths during the mean follow-up period of 27 months. Early and late complication rates were 33% and 36%, respectively, in patients with acute dissection, whereas rates were 4% and 0% (P <.05 vs patients with acute dissection) in patients with chronic dissection. CONCLUSIONS: Entry closure with endovascular stent-graft placement may be a safe and effective method for the treatment of patients with aortic dissection. It could be an alternative to conventional surgical intervention in selected patients with chronic dissection. However, strict patient selection and close follow-up seem mandatory in patients with acute dissection receiving Z stent-based stent-grafts. Stent-graft repair should be delayed for acute type B dissection without complications.     

Randomized study of the benefits of preoperative corticosteroid administration on the postoperative morbidity and cytokine response in patients undergoing surgery for esophageal cancer

OBJECTIVE: To investigate whether preoperative corticosteroid administration plays a role in attenuating postoperative morbidity. SUMMARY BACKGROUND DATA: There is as yet no consensus on the beneficial effects of steroids in alleviating surgical stress. METHODS: A total of 66 patients undergoing surgery for thoracic esophageal cancer were randomly categorized preoperatively into two groups of 33 patients each. One group was administered an intravenous infusion of methylprednisolone (10 mg/kg body weight) 30 minutes before the surgery (MP group), while the other group received a placebo infusion (control group). The primary endpoint was organ system failure during the first 7 days after surgery. Comparisons of surgery-related complications, cytokine responses, and blood counts were also made between the two groups. RESULTS: The percentage of patients in the MP group who had one or more organ system failures was 33%, significantly lower than the corresponding percentage of 61% in the control group. The surgery-related complication rate and long-term survival rate were similar in the two groups. The peak plasma levels of interleukin (IL)-1 receptor antagonist, IL-6, and IL-8 were significantly lower in the MP group than in the control group. Changes in the plasma levels of IL-10 were significantly larger in the MP group. No significant differences in the circulating lymphocyte and neutrophil counts were observed between the groups. CONCLUSIONS: The results suggest that prophylactic administration of corticosteroids is associated with a decrease in postoperative morbidity in patients undergoing invasive surgery. The laboratory data suggest that corticosteroids may attenuate surgical stress-induced inflammatory responses both directly by suppressing the release of proinflammatory cytokines and via inducing IL-10 synthesis.     

Myelopathy due to scoliosis with vertebral hypertrophy in Klippel-Trenaunay-Weber syndrome

We describe a 37-year-old man complaining of right back pain and gait disturbance. He had a big soft tumor on his right back, hemihypertrophy of the right lower extremity, and right thoracic scoliosis. We diagnosed Klippel-Trenaunay-Weber syndrome based on the pathological findings of the soft tumor. Computed tomography (CT) scan revealed severe spinal stenosis due to a hypertrophic vertebral body and facet joint at T7. Treatment by decompression of hypertrophic bone led to complete neurological recovery. To our knowledge, no case has been reported of Klippel-Trenaunay-Weber syndrome with myelopathy which originated from thoracic scoliosis with a hypertrophic facet joint and vertebral body. We suggest that the cause of myelopathy in Klippel-Trenaunay-Weber syndrome originated not only from arteriovenous fistula, medullary angioma, and extradural hemangioma but also vertebral hypertrophy with scoliosis.     

Pathogenic implications of remnant vitelline structures in gastroschisis

Purpose

The pathogenesis of gastroschisis is unknown. It may be helpful in understanding its pathogenesis to know the structural relationships among umbilical components including umbilical vessels, urachus, and vitelline structures, and thus, the authors investigated the remnants of vitelline structures in a series of cases of gastroschisis.

Methods

Medical records of 41 cases with gastroschisis treated in our institute from 1979 to 2009 were retrospectively reviewed.

Results

Paraumbilical bands, possible remnants of vitelline structures, were observed in 4 cases (9.8%). All 4 bands were attached to the skin edge of the abdominal defect without incorporation into the umbilical cord. The band ended at the mesentery in 3 cases and at the antimesenteric site of the ileum in the remaining case. Histologic findings showed fibrous tissues in all cases. One was possibly associated with the development of colonic atresia. Another was noticed after silo reduction when herniated bowels became strangulated by the band. The other 2 cases were uncomplicated.

Conclusions

Our findings may support the recently proposed hypothesis that the developmental failure of the yolk sac and related vitelline structures to merge with or to be incorporated into the umbilical stalk might be associated with the pathogenesis of the abdominal wall defect in gastroschisis. Paraumbilical bands derived from vitelline structures may possibly cause intestinal ischemia prenatally or postnatally.