The Value of Diffusion-Weighted MRI in the Diagnosis of Cerebral Fat Embolism

Fat embolism syndrome complicates open fractures involving long bones, although it occasionally follows nontraumatic conditions. Incomplete forms of the syndrome (ie, cerebral fat embolism) represent a challenge to diagnosis, and brain MRI represents a valuable diagnostic tool. We describe a patient who had a fat embolism to the brain after an isolated traumatic open fracture of the tibia. MRI with T2 and diffusion-weighted images revealed multiple, reversible brain lesions, suggesting vasogenic edema and consistent with this entity. At present, MR imaging is the most sensitive technique to evaluate cerebral fat embolism.     

脑脂肪栓塞早期诊断及治疗

目的探讨脑脂肪栓塞的早期诊断及治疗。方法回顾性分析我院收治的颅脑外伤并发脑脂肪栓塞2例。结果患者MRI提示两侧大脑半球、基底节区、卵圆中心及脑干可见多发斑点斑块状等T1、长T2异常信号影,液体衰减反转成像（FLAIR）呈高信号,弥散加权成像（DWI）呈高信号。患者凝血机制也发生改变。结论通过早期的MRI结合凝血机制改变可以尽早诊断脑脂肪栓塞,使患者得到有效救治。     

Residual lesions of cerebral fat embolism

Summary Necropsy findings of a case which survived for three months after massive cerebral fat embolism are presented. The lesions are charcterized by numerous patchy necroses and areas of demyelination in the white matter of cerebral and cerebellar hemispheres and brain stem, accompanied by atrophy of white matter and ventricular enlargement. Attention is drawn to the significance of these lesions for posttraumatic coma or dementia.

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Zusammenfassung Ein Fall von Spätläsionen nach massiver zerebraler Fettembolie zeigt zahlreiche fleckförmige Nekrosen und Zonen von Demyelinisierung der weißen Substanz der Großhirn- und Kleinhirnhemisphären und des Hirnstammes. Auf die Bedeutung dieser Läsionen für die Entstehung eines posttraumatischen Coma oder posttraumatischen Demenz wird hingewiesen.

     

Magnetic resonance findings in two episodes of repeated cerebral fat embolisms in a patient with autologous fat injection into the face

We report magnetic resonance image (MRI) and magnetic resonance spectroscopy (MRS) findings in a patient of cerebral fat embolism (CFE) occurred in a 26-year-old woman after an autologous fat injection into the face. After initial neurologic symptom onset, MRI and MRS data were obtained two times to investigate repeated CFE. We obtained the MRS data in the two different time intervals and two different echo times to compare the lesions with normal brain parenchyma. The results of MRS data showed that a decrease in N-acetyl-aspartate, an increase in lactate and a very high early peak of free lipids between 0.9 and 1.4 ppm were obtained at the acute infarcted lesion as compared with normal brain parenchyma. In addition, these findings were more clearly detected on short echo time spectrum rather than long spectrum. A close relationship between the clinical manifestations and MRI and MRS findings of the brain can helpful to distinguish CFE with other conditions and to evaluate the cause materials of infarctions rather than conventional MRI or diffusion-weighted imaging.     

MR imaging and 1H-MR spectroscopy in a case of cerebral infarction with transient cerebral arteriopathy

A case of cerebral infarction with transient cerebral arteriopathy in a 12-year-old female is described. The child showed with an acute onset of left hemiplegia, central facial palsy and aphasia. She was diagnosed with right internal carotid artery obstruction with no predisposing factors for cerebral infarction. A serial MR image and MR spectroscopy of the brain was performed. MR angiography revealed reversible vascular changes in the right middle cerebral artery after several months. The ratio of choline/creatine was elevated and that of N-acetylaspartate (NAA)/creatine was depressed in the cerebral lesion, however, they were normalized during the remission phase with long echo time-MR spectroscopy. The elevation of the lactate peak was clarified with short echo time-MR spectroscopy. The longitudinal follow up using MR angiography, and MR spectroscopy with long and short echo time was useful for the evaluation of reversible vascular change with cerebral infarction in children.     

Protective effects of AVS 1,2-bis (nicotinamido)-propane, against cold-induced brain edema: magnetic resonance imaging and spectroscopy

It was hypothesized that AVS 1,2-bis(nicotinamide)-propane, a free radical scavenger, could potentially be useful for the treatment of brain edema. Vasogenic brain edema was produced by freezing brain regions in 36 rats that had been treated with either AVS or saline. The efficacy of treatment was analyzed using proton magnetic resonance imaging (¹H MRI) and proton magnetic resonance spectroscopy (¹H MRS) of perchloric acid tissue extracts. T2-weighted MRI was obtained at 1 and 24 h after freezing. For ¹H MRS studies, rats were killed using liquid nitrogen and the extracted metabolites from the frozen hemispheres analyzed. ¹H MRI showed the edema lesion that indicated a region of a high signal intensity gradually extended and increased in intensity. Suppression of the edema development was observed in the AVS-treated group. Shortly after injury, the levels of acetate and lactate rapidly rose. Subsequently, the amino acid of alanine was also increased and N-acetyl aspartate and glutamine were markedly depressed. In AVS-treated rats, increases of lactate and alanine, and decreases of N-acetyl aspartate were statistically significant. We concluded that AVS is valuable for the treatment of vasogenic brain edema using these MR techniques.     

Cerebral fat embolism syndrome at a single trauma center

ObjectivesBased on a 16-year case series, we sought lessons about diagnosis and treatment of cerebral fat embolism syndrome.Materials and methodsUsing discharge codes at a Level 1 Trauma Center, we performed a retrospective chart review of clinical characteristics, diagnostic studies, treatments, and outcome in cerebral fat embolism syndrome.ResultsThirty-nine (40%) of 97 patients with fat embolism syndrome were diagnosed with cerebral fat embolism syndrome, with 29 (74%) presenting with coma. All had abnormal brain magnetic resonance imaging, with scattered cytotoxic edema (starfield pattern) in 29 (74%). All but two of the 21 patients with dilated fundoscopy showed retinal embolism. Among 29 patients with transcranial Doppler, the presence of microembolic signals in 15 (52%) was associated with fever (p = 0.039), right-to-left intracardiac shunting (p = 0.046) and a trend towards initial coma. In 11 patients with serial transcranial Dopplers and treatment with high-intensity statin therapy, the frequency of microembolic signals tended to decrease after therapy was initiated. Of the 28 (72%) of the 39 patients discharged, 16 (57%) had mild to moderate disability at last follow up.ConclusionsThe recognition of cerebral fat embolism syndrome may be improved with routine inclusion of brain magnetic resonance imaging, dilated fundoscopy, and transcranial Doppler. We share our empiric management algorithm for cerebral fat embolism syndrome using these studies and with consideration of experimental therapies in select patients to prevent ongoing cerebral injury.     

Changes of MRI in inter-spinal distraction fusion for lumbar degenerative disease: A retrospective analysis covering 3 years

ObjectiveTo assess the preoperative and postoperative changes in MRI image and the short-term efficacy of the ISDF with BacFuse covering 3 years.Methods32 patients who underwent ISDF were involved in this retrospective study. The symptoms assessment including VAS, ODI, and SF-12 were evaluated preoperative and postoperative at 1 year and 3 years. The X-ray was used to measure posterior disk height (PDH), foramina height (FH), foramina width (FW), and MRI was taken to assess the cross-sectional area of dura sac (CSADS), cross-sectional area of canal (CSAC), herniated disc area, ligamentum flavum area. The preoperative ratio of herniated disc area and ligamentum flavum area to CSAC were compared with post-operative ratio. The modified Pfirrmann grade system was used to assess the surgical lumbar disc.ResultsThe symptom indexes were significantly improved after surgery. PDH and FH increased significantly (P < 0.05) after surgery compared with that before surgery, but there was no statistical difference in FW (P > 0.05). CSADS and CSAC increased obviously (P < 0.05), while the area of herniated disc and ligamentum flavum decreased significantly (P < 0.05). The ratio changes showed a significant difference between last follow-up and pre-operation (P < 0.05), but there was no statistical significance in grade changes of surgical disc.ConclusionISDF with BacFuse could relieve clinical symptoms and expanse the spinal canal area in MRI. During 3-year observation, it could provide continuous traction and maintain the area of spinal canal, so as to partially retract the herniated disc and make it possible to repair the disc.     

Predictive blood coagulation markers for early diagnosis of venous thromboembolism after total knee joint replacement

Pulmonary embolism development may be prevented if asymptomatic venous thromboembolism (VTE) can be predicted and treated preoperatively or soon after total knee arthroplasty (TKA). The purpose of this study was to evaluate whether asymptomatic VTE can be predicted by blood coagulation markers preoperatively or early after TKA. This prospective single-centre study enrolled 68 patients (6 men, 62 women; mean age: 71 years) who underwent TKA between September 2004 and August 2009. Sixteen-row multidetector computed tomography was performed 4 days before and after surgery for diagnosis of asymptomatic VTE. Blood samples were taken to measure the plasma levels of soluble fibrin monomer complex (SFMC), D-dimer and cross-linked fibrin degradation products by leukocyte elastase (e-XDP) at 4 days preoperatively, and at 1 hour, 1 day and 4 days postoperatively. The preoperative SFMC, D-dimer and e-XDP levels did not differ significantly between the thrombus (n = 36) and no-thrombus (n = 32) groups. D-dimer and e-XDP levels showed the most significant increases at days 4 and 1, respectively, after surgery in the thrombus group. With cut-off points of 7.5 μg/ml for D-dimer and 8.2 U/ml for e-XDP, the sensitivities were 75% and 75%, and the specificities were 63% and 59%, respectively. By multiple logistic regression analysis, D-dimer at day 4 and e-XDP at day 1 postoperatively were independent markers for early diagnosis of VTE (odds ratio = 1.61 and 1.19, P = 0.01 and 0.04, respectively). The postoperative occurrence of new asymptomatic VTE may be predicted by D-dimer at day 4 and e-XDP at day 1 after TKA.     

Safety and Efficacy of Edoxaban,an Oral Factor Xa Inhibitor,Versus Enoxaparin for Thromboprophylaxis After Total Knee Arthroplasty: The STARS E-3 Trial

Introduction

This phase 3 trial compared the safety and efficacy of edoxaban, an oral direct factor Xa inhibitor, with enoxaparin sodium (enoxaparin) for thromboprophylaxis after total knee arthroplasty (TKA) in patients in Japan and Taiwan.

Materials and methods

In this randomized, double-blind, double-dummy study, patients received oral edoxaban 30 mg once daily beginning 6 to 24 hours postsurgery or enoxaparin 2000 IU (equivalent to 20 mg) subcutaneously twice daily beginning 24 to 36 hours postsurgery for 11 to 14 days. The primary efficacy endpoint was the composite of symptomatic pulmonary embolism and symptomatic and asymptomatic deep vein thrombosis. Safety endpoints included the incidence of major bleeding, clinically relevant non-major (CRNM) bleeding, major bleeding or CRNM bleeding, all bleeding events, adverse events, and adverse drug reactions.

Results

Of 716 patients enrolled, 360 and 356 were randomized to receive edoxaban or enoxaparin, respectively. The primary efficacy outcome occurred in 22/299 (7.4%) and 41/295 (13.9%) patients in the edoxaban and enoxaparin groups, respectively (relative risk reduction = 46.8%), indicating non-inferiority (P < 0.001) and superiority (P = 0.010) of edoxaban versus enoxaparin. In the edoxaban and enoxaparin groups, major bleeding occurred in 4/354 (1.1%) versus 1/349 (0.3%) patients (P = 0.373); major or CRNM bleeding occurred in 22/354 (6.2%) versus 13/349 (3.7%) patients (P = 0.129), respectively.

Conclusions

Edoxaban 30 mg once daily was more effective for thromboprophylaxis than subcutaneous enoxaparin 2000 IU twice daily following TKA and demonstrated a similar incidence of bleeding events.     

Stent retriever thrombectomy for acute ischemic stroke: A systematic review and meta-analysis of randomized controlled trials,including THRACE

Background and purpose

Endovascular thrombectomy has become the reference therapy for patients with large vessel occlusion (LVO). However, no meta-analysis including the THRACE Trial has yet been reported. Thus, the present review assessed the outcomes of stent retriever thrombectomy added to medical care compared with medical care alone in LVO patients.

Review of synthetic MRI in pediatric brains: Basic principle of MR quantification,its features,clinical applications,and limitations

Quantitative magnetic resonance imaging (MRI) with multislice, multi-echo, and multi-delay acquisition enables simultaneous quantification of R₁ and R₂ relaxation rates, proton density, and the B₁ field in a single acquisition, and requires only about 6 minutes for full-head coverage. Using dedicated SyMRI software, radiologists can generate any contrast-weighted image by manipulating the acquisition parameters, including repetition time, echo time, and inversion time. Moreover, automatic brain tissue segmentation, volumetry, and myelin measurement can also be performed. Using the SyMRI approach, a shorter scan time, an objective examination, and personalized MR imaging parameters can be obtained in daily clinical pediatric imaging. Here we summarize and review the use of SyMRI in imaging of the pediatric brain, including the basic principles of MR quantification along with its features, clinical applications, and limitations.     

A circuitry and biochemical basis for tuberous sclerosis symptoms: from epilepsy to neurocognitive deficits

Tuberous sclerosis complex (TSC) is an autosomal dominant monogenetic disorder that is characterized by the formation of benign tumors in several organs as well as brain malformations and neuronal defects. TSC is caused by inactivating mutations in one of two genes, TSC1 and TSC2, resulting in increased activity of the mammalian Target of Rapamycin (mTOR). Here, we explore the cytoarchitectural and functional CNS aberrations that may account for the neurological presentations of TSC, notably seizures, hydrocephalus, and cognitive and psychological impairments. In particular, recent mouse models of brain lesions are presented with an emphasis on using electroporation to allow the generation of discrete lesions resulting from loss of heterozygosity during perinatal development. Cortical lesions are thought to contribute to epileptogenesis and worsening of cognitive defects. However, it has recently been suggested that being born with a mutant allele without loss of heterozygosity and associated cortical lesions is sufficient to generate cognitive and neuropsychiatric problems. We will thus discuss the function of mTOR hyperactivity on neuronal circuit formation and the potential consequences of being born heterozygous on neuronal function and the biochemistry of synaptic plasticity, the cellular substrate of learning and memory. Ultimately, a major goal of TSC research is to identify the cellular and molecular mechanisms downstream of mTOR underlying the neurological manifestations observed in TSC patients and identify novel therapeutic targets to prevent the formation of brain lesions and restore neuronal function.