Accuracy of computed tomography angiography in the detection of pulmonary embolism in patients with high body weight

BACKGROUND The accuracy of CT pulmonary angiography (CTPA) in detecting or excluding pulmonary embolism has not yet been assessed in patients with high body weight (BW). METHODS This retrospective study involved CTPAs of 114 patients weighing 75-99 kg and those of 123 consecutive patients weighing 100-150 kg. Three independent blinded radiologists analyzed all examinations in randomized order. Readers' data on pulmonary emboli were compared with a composite reference standard, comprising clinical probability, reference CTPA result, additional imaging when performed and 90-day follow-up. Results in both BW groups and in two body mass index (BMI) groups (BMI <30 kg/m(2) and BMI ≥ 30 kg/m(2), i.e., non-obese and obese patients) were compared. RESULTS The prevalence of pulmonary embolism was not significantly different in the BW groups (P=1.0). The reference CTPA result was positive in 23 of 114 patients in the 75-99 kg group and in 25 of 123 patients in the ≥ 100 kg group, respectively (odds ratio, 0.991; 95% confidence interval, 0.501 to 1.957; P=1.0). No pulmonary embolism-related death or venous thromboembolism occurred during follow-up. The mean accuracy of three readers was 91.5% in the 75-99 kg group and 89.9% in the ≥ 100 kg group (odds ratio, 1.207; 95% confidence interval, 0.451 to 3.255; P=0.495), and 89.9% in non-obese patients and 91.2% in obese patients (odds ratio, 0.853; 95% confidence interval, 0.317 to 2.319; P=0.816). CONCLUSION The diagnostic accuracy of CTPA in patients weighing 75-99 kg or 100-150 kg proved not to be significantly different.

Quality of life after pulmonary embolism: Prospective validation of the German version of the PEmb-QoL questionnaire.

BACKGROUND The Pulmonary Embolism Quality of Life questionnaire (PEmb-QoL) is a 40-item questionnaire to measure health-related quality of life in patients with pulmonary embolism. It covers six 6 dimensions: frequency of complaints, limitations in activities of daily living, work-related problems, social limitations, intensity of complaints, and emotional complaints. Originally developed in Dutch and English, we prospectively validated a German version of the PEmb-QoL. METHODS A forward-backward translation of the English version of the PEmb-QoL into German was performed. German-speaking consecutive adult patients aged ≥18 years with an acute, objectively confirmed pulmonary embolism discharged from a Swiss university hospital (01/2011-06/2013) were recruited telephonically. Established psychometric tests and criteria were used to evaluate the acceptability, reliability, and validity of the German PEmb-QoL questionnaire. To assess the underlying dimensions, an exploratory factor analysis was performed. RESULTS Overall, 102 patients were enrolled in the study. The German version of the PEmb-QoL showed a good internal consistency (Cronbach's alpha ranging from 0.72 to 0.96), item-total (0.53-0.95) and inter-item correlations (>0.4), and test-retest reliability (intra-class correlation coefficients 0.59-0.89) for the dimension scores. A moderate correlation of the PEmb-QoL with SF-36 dimension and summary scores (0.21-0.83) indicated convergent validity, while low correlations of PEmb-QoL dimensions with clinical characteristics (-0.16-0.37) supported discriminant validity. The exploratory factor analysis suggested four underlying dimensions: limitations in daily activities, symptoms, work-related problems, and emotional complaints. CONCLUSION The German version of the PEmb-QoL questionnaire is a valid and reliable disease-specific measure for quality of life in patients with pulmonary embolism.

Visualization and quantification of air embolism structure by processing postmortem MSCT data.

Venous air embolism (VAE) is an often occurring forensic finding in cases of injury to the head and neck. Whenever found, it has to be appraised in its relation to the cause of death. While visualization and quantification is difficult at traditional autopsy, Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) offer a new potential in the diagnosis of VAE. This paper reports the findings of VAE in four cases of massive head injury examined postmortem by Multislice Computed Tomography (MSCT) prior to autopsy. MSCT data of the thorax were processed using 3D air structure reconstruction software to visualize air embolism within the vascular system. Quantification of VAE was done by multiplying air containing areas on axial 2D images by their reconstruction intervals and then by summarizing the air volumes. Excellent 3D visualization of the air within the vascular system was obtained in all cases, and the intravascular gas volume was quantified.

von Willebrand factor-mediated platelet adhesion is critical for deep vein thrombosis in mouse models

Deep vein thrombosis (DVT) and its complication, pulmonary embolism, are frequent causes of disability and mortality. Although blood flow disturbance is considered an important triggering factor, the mechanism of DVT initiation remains elusive. Here we show that 48-hour flow restriction in the inferior vena cava (IVC) results in the development of thrombi structurally similar to human deep vein thrombi. von Willebrand factor (VWF)-deficient mice were protected from thrombosis induced by complete (stasis) or partial (stenosis) flow restriction in the IVC. Mice with half normal VWF levels were also protected in the stenosis model. Besides promoting platelet adhesion, VWF carries Factor VIII. Repeated infusions of recombinant Factor VIII did not rescue thrombosis in VWF(-/-) mice, indicating that impaired coagulation was not the primary reason for the absence of DVT in VWF(-/-) mice. Infusion of GPG-290, a mutant glycoprotein Ib?-immunoglobulin chimera that specifically inhibits interaction of the VWF A1 domain with platelets, prevented thrombosis in wild-type mice. Intravital microscopy showed that platelet and leukocyte recruitment in the early stages of DVT was dramatically higher in wild-type than in VWF(-/-) IVC. Our results demonstrate a pathogenetic role for VWF-platelet interaction in flow disturbance-induced venous thrombosis.

Cardiovascular changes after PMMA vertebroplasty in sheep: the effect of bone marrow removal using pulsed jet-lavage

Clinically, the displacement of intravertebral fat into the circulation during vertebroplasty is reported to lead to problems in elderly patients and can represent a serious complication, especially when multiple levels have to be treated. An in vitro study has shown the feasibility of removing intravertebral fat by pulsed jet-lavage prior to vertebroplasty, potentially reducing the embolization of bone marrow fat from the vertebral bodies and alleviating the cardiovascular changes elicited by pulmonary fat embolism. In this in vivo study, percutaneous vertebroplasty using polymethylmethacrylate (PMMA) was performed in three lumbar vertebrae of 11 sheep. In six sheep (lavage group), pulsed jet-lavage was performed prior to injection of PMMA compared to the control group of five sheep receiving only PMMA vertebroplasty. Invasive recording of blood pressures was performed continuously until 60 min after the last injection. Cardiac output and arterial blood gas parameters were measured at selected time points. Post mortem, the injected cement volume was measured using CT and lung biopsies were processed for assessment of intravascular fat. Pulsed jet-lavage was feasible in the in vivo setting. In the control group, the injection of PMMA resulted in pulmonary fat embolism and a sudden and significant increase in mean pulmonary arterial pressure. Pulsed jet-lavage prevented any cardiovascular changes and significantly reduced the severity of bone marrow fat embolization. Even though significantly more cement had been injected into the lavaged vertebral bodies, significantly fewer intravascular fat emboli were identified in the lung tissue. Pulsed jet-lavage prevented the cardiovascular complications after PMMA vertebroplasty in sheep and alleviated the severity of pulmonary fat embolism.

Clinical radiology and postmortem imaging (Virtopsy) are not the same: Specific and unspecific postmortem signs

The aim of this article is to disclose the characteristics of postmortem forensic imaging; give an overview of the several possible findings in postmortem imaging, which are uncommon or new to clinical radiologists; and discuss the possible pitfalls. Unspecific postmortem signs are enlisted and specific signs shall be presented, which are typical for one cause of death. Unspecific signs. Livor mortis may not only be seen from the outside, but also inside the body in the lungs: in chest CT internal livor mortis appear as ground glass opacity in the dependent lower lobes. The aortic wall is often hyperdense in postmortem CT due to wall contraction and loss of luminal pressure. Gas bubbles are very common postmortem due to systemic gas embolism after major open trauma, artificial respiration or initial decomposition; in particular putrefaction produces gas bubbles globally. Specific signs. Intracranial bleeding is hyperattenuating both in radiology and in postmortem imaging. Signs of strangulation are hemorrhage in the soft tissue of the neck like skin, subcutaneous tissue, platysma muscle and lymph nodes. The "vanishing" aorta is indicative for exsanguination. Fluid in the airways with mosaic lung densities and emphysema (aquosum) is typical for fresh-water drowning.

Low-dose pulmonary CT angiography: reduced radiation exposure and iodine load at low tube kilovoltage

CT pulmonary angiography is the currently accepted standard in ruling out acute pulmonary embolism. Issues of radiation dose received by patients via CT have been extensively disputed by radiologists and reported by the media. In recent years there has been considerable research performed to find ways for reducing radiation exposure from CT. Herein, we will discuss specific measures that have been shown to be valuable for CT pulmonary angiography. The limitations and the potential benefits of reduced CT peak tube kilovoltage will be detailed as this method is capable of reducing both radiation exposure and iodine load to the patient simultaneously. We discuss some of the emerging tools, which will hopefully play a significant role in wider acceptance of low-dose CT pulmonary angiography protocols.

Anomalous global effects induced by 'blind' distractors in visual hemifield defects

Previous research has revealed that a stimulus presented in the blind visual field of participants with visual hemifield defects can evoke oculomotor competition, in the absence of awareness. Here we studied three cases to determine whether a distractor in a blind hemifield would be capable of inducing a global effect, a shift of saccade endpoint when target and distractor are close to each other, in participants with lesions of the optic radiations or striate cortex. We found that blind field distractors significantly shifted saccadic endpoints in two of three participants with lesions of either the striate cortex or distal optic radiations. The direction of the effect was paradoxical, however, in that saccadic endpoints shifted away from blind field distractors, whereas endpoints shifted towards distractors in the visible hemifields, which is the normal global effect. These results provide further evidence that elements presented in the blind visual field can generate modulatory interactions in the oculomotor system, which may differ from interactions in normal vision.

Automated cement segmentation in vertebroplasty

Vertebroplasty is a minimally invasive procedure with many benefits; however, the procedure is not without risks and potential complications, of which leakage of the cement out of the vertebral body and into the surrounding tissues is one of the most serious. Cement can leak into the spinal canal, venous system, soft tissues, lungs and intradiscal space, causing serious neurological complications, tissue necrosis or pulmonary embolism. We present a method for automatic segmentation and tracking of bone cement during vertebroplasty procedures, as a first step towards developing a warning system to avoid cement leakage outside the vertebral body. We show that by using active contours based on level sets the shape of the injected cement can be accurately detected. The model has been improved for segmentation as proposed in our previous work by including a term that restricts the level set function to the vertebral body. The method has been applied to a set of real intra-operative X-ray images and the results show that the algorithm can successfully detect different shapes with blurred and not well-defined boundaries, where the classical active contours segmentation is not applicable. The method has been positively evaluated by physicians.

Unmyelinated afferents in human skin and their responsiveness to low temperature

In humans, there are different types of cutaneous cold-sensitive afferents responsible for cold sensation and cold pain. Innocuous cold is primarily mediated by a population of slow A delta afferents, based on psychophysical and neurophysiological studies. Noxious cold (usually below 15 degrees C) is mediated, at least in part, by polymodal nociceptors. There is also a population of unmyelinated afferents responsive to innocuous low temperature, some of which also respond to heat, whose sensory function has not been completely defined. A paradoxical hot/burning evoked by cooling is unmasked by A-fibre block, and similar sensations are evoked by applying simultaneous cool and warm stimuli to adjacent skin areas. These unmyelinated fibres activated by innocuous cooling (and heating) may contribute to this hot/burning sensation, along with other thermoregulatory functions.

Safety, effectiveness and predictors for early reoperation in therapeutic and prophylactic vertebroplasty: short-term results of a prospective case series of patients with osteoporotic vertebral fractures

Abstract Introduction Vertebroplasty (VP) is a cost-efficient alternative to kyphoplasty; however, regarding safety and vertebral body (VB) height restoration, it is considered inferior. We assessed the safety and efficacy of VP in alleviating pain, improving quality of life (QoL) and restoring alignment. Methods In a prospective monocenter case series from May 2007 until July 2008, there were 1,408 vertebroplasties performed during 319 interventions in 306 patients with traumatic, lytic and osteoporotic fractures. The 249 interventions in 233 patients performed because of osteoporotic vertebral fractures were analyzed regarding demographics, treatment and radiographic details, pain alleviation (VAS), QoL improvement (NASS and EQ-5D), complications and predictors for new fractures requiring a reoperation. Results The osteoporotic patient sample consisted of 76.7% (179) females with a median age of 80 years. A total of 54 males had a median age of 77 years. On average, there were 1.8 VBs fractured and 5 VBs treated. The preoperative pain was assessed by the visual analog scale (VAS) and decreased from 54.9 to 40.4 pts after 2 months and 31.2 pts after 6 months. Accordingly, the QoL on the EQ-5D measure (−0.6 to 1) improved from 0.35 pts before surgery to 0.56 pts after 2 and to 0.68 pts after 6 months. The preoperative Beck Index (anterior height/posterior height) improved from a mean of 0.64 preoperative to 0.76 postoperative, remained stable at 2 months and slightly deteriorated to 0.72 at 6 months postoperatively. There were cement leakages in 26% of the fractured VBs and in 1.4% of the prophylactically cemented VBs; there were symptoms in 4.3%, and most of them were temporary hypotension and one pulmonary cement embolism that remained asymptomatic. The univariate regression model revealed a tendency for a reduced risk for new or refractures on radiographs (OR = 2.61, 95% CI 0.92–7.38, p = 0.12) and reoperations (OR = 2.9, 95% CI 0.94–8.949, p = 0.1) when prophylactic augmentation was performed. The final multivariate regression model revealed male patients to have an about three times higher refracture risk (radiographic) (OR = 2.78, p = 0.02) at 6 months after surgery. Patients with a lumbar index fracture had an about three to five times higher refracture/reoperation risk than patients with a thoracic (OR = 0.33/0.35, p = 0.009/0.01) or thoracolumbar (OR = 0.32/0.22, p = 0.099/0.01) index fracture. Conclusion If routinely used, VP is a safe and efficacious treatment option for osteoporotic vertebral fractures with regard to pain relief and improvement of the QoL. Even segmental realignment can be partially achieved with proper patient positioning. Certain patient or fracture characteristics increase the risk for early radiographic refractures or new fractures, or a reoperation; a consequent prophylactic augmentation showed protective tendencies, but the study was underpowered for a final conclusion.

Transcranial Doppler-detected cerebral embolic load during transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is an alternative to surgery for high-risk patients with severe aortic valve stenosis. Periprocedural stroke is reported at an incidence up to 10%. Magnetic resonance imaging studies have identified new onset of clinically silent ischaemic cerebral lesions more frequently (68-84%). So far, few data are available about cerebral embolism during TAVI. The aim of this study was to determine the frequency of high-intensity transient signals (HITS) and to explore differences in the HITS pattern between transfemoral and transapical access and between self-expanding (SE) and balloon-expandable (BE) deployment technique.

Recombinant human factor VIIa prevents hysterectomy in severe postpartum hemorrhage: single center study

Abstract Objective: To evaluate the effectiveness of human recombinant activated factor VII (rhFVIIa, NovoSeven) in avoiding hysterectomy postpartum in the management of severe postpartum hemorrhage (PPH). Methods: We performed a prospective cohort study at our university tertiary care center. Patients with severe post partum hemorrhage (blood loss >2000 mL) and failed medical and uterus-preserving surgical management, were treated with intravenous bolus administration of rhVIIa. Main outcome measures were cessation of bleeding, postpartum hysterectomy and thromboembolic events. Results: In 20/22 patients included, PPH was caused primarily by uterine atony, including 7 (32%) with additional lower genital tract lesion; in two women, it was due to pathologic placentation (placenta increta, 9%). One case of amniotic fluid embolism and one woman with uterine inversion were included. Recombinant hFVIIa was successful in stopping the PPH and in preventing a hysterectomy in 20/22 women (91%). The remaining two patients with persistent bleeding despite rhFVIIa treatment, who underwent postpartum hysterectomy, had placenta increta. No thromboembolic event was noticed. Conclusions: This study describes the largest single center series of rhFVIIa treatment for fertility preservation in severe postpartum hemorrhage published to date. Our data suggest that administration of rhFVIIa is effective in avoiding postpartum hysterectomy after conservative medical and surgical measures have failed. Although randomized studies are lacking, rhFVIIa should be considered as a second-line therapeutic option of life-threatening postpartal bleeding, in particular if preservation of fertility is warranted and hysterectomy is to be avoided.