Detection of acute pulmonary embolism using native repeated magnetic resonance imaging acquisitions under free-breathing and without respiratory or cardiac gating. A diagnostic accuracy study.

Objectives: Computed tomography pulmonary angiography (CTPA) is the gold standard diagnostic method for patients with suspected pulmonary embolism (PE), but it has its drawbacks, including exposure to ionizing radiation and iodinated contrast agent. The present study aims to evaluate the diagnostic performance of our in-house developed non-contrast MRI protocol for PE diagnosis in reference to CTPA. Methods: 107 patients were included, all of whom underwent MRI immediately before or within 36 hours after CTPA. Additional cases examined only with MRI and a negative result were added to reach a PE prevalence of approximately 20%. The protocol was a non-contrast 2D steady-state free precession (SSFP) sequence under free-breathing, without respiratory or cardiac gating, and repeated five times to capture the vessels at different breathing/cardiac phases. The MRIs were blinded and read by two radiologists and the results were compared to CTPA. Results: Of the 243 patients included, 47 were positive for PE. Readers 1 and 2 demonstrated 89% and 87% sensitivity, 100% specificity, 98% accuracy and Cohen's kappa of 0.88 on patient level. In the per embolus comparison, readers 1 and 2 detected, 60 and 59/61 (98, 97%) proximal, 101 and 94/113 (89, 83%) segmental, and 5 and 2/32 (16, 6%) subsegmental emboli, resulting in 81 and 75% sensitivity respectively. Conclusion: The repeated 2D SSFP can reliably be used for the diagnosis of acute PE at the proximal and segmental artery levels.

Cost-Effectiveness of Performing Reference Ultrasonography in Patients with Deep Vein Thrombosis.

BACKGROUND: The diagnosis of recurrent ipsilateral deep vein thrombosis (DVT) with compression ultrasonography (CUS) may be hindered by residual intravascular obstruction after previous DVT. A reference CUS, an additional ultrasound performed at anticoagulant discontinuation, may improve the diagnostic work-up of suspected recurrent ipsilateral DVT by providing baseline images for future comparison. OBJECTIVES: To evaluate the cost-effectiveness of routinely performing reference CUS in DVT patients. METHODS: Patient-level data (n = 96) from a prospective management study (Theia study; NCT02262052) and claims data were used in a decision analytic model to compare 12 scenarios for diagnostic management of suspected recurrent ipsilateral DVT. Estimated health care costs and mortality due to misdiagnosis, recurrent venous thromboembolism, and bleeding during the first year of follow-up after presentation with suspected recurrence were compared. RESULTS: All six scenarios including reference CUS had higher estimated 1-year costs (€1,763-€1,913) than the six without reference CUS (€1,192-€1,474). Costs were higher because reference CUS results often remained unused, as 20% of patients (according to claims data) would return with suspected recurrent DVT. Estimated mortality was comparable in scenarios with (14.8-17.9 per 10,000 patients) and without reference CUS (14.0-18.5 per 10,000). None of the four potentially most desirable scenarios included reference CUS. CONCLUSION: One-year health care costs of diagnostic strategies for suspected recurrent ipsilateral DVT including reference CUS are higher compared to strategies without reference CUS, without mortality benefit. These results can inform policy-makers regarding use of health care resources during follow-up after DVT. From a cost-effectiveness perspective, the findings do not support the routine application of reference CUS.

Swedish obstetric thromboprophylaxis guideline: background and update.

Risk estimation concerning venous thromboembolism (VTE) and thromboprophylaxis for those at risk is routine in pregnancy. For 20 years, Swedish obstetricians have followed a weighted-risk algorithm guideline for risk estimation, based on which patient selection, timing, duration and dosage of thromboprophylaxis are determined. This article presents the latest update, the basis for the algorithm and its application for assessing moderate- to high obstetric VTE risk, defined as equal or greater absolute risk per time unit than the antepartum risk of women with one prior VTE. The risk score is based on risk factors conferring approximately fivefold increased risk of VTE or a multiple thereof. This article also presents algorithm efficacy data and describes lifestyle advice provided to patients. In our experience, the Swedish guideline for obstetric VTE risk estimation is easy to follow. It helps identify women at high risk. The risk of under- or overtreatment is thus minimised.

Neutrophil extracellular trap formation is an independent risk factor for occult cancer in patients presenting with venous thromboembolism.

BACKGROUND: Venous thromboembolism (VTE), particularly unprovoked VTE, is associated with occult cancer. The optimal screening regimen remains controversial. Neutrophil extracellular traps (NETs) are implicated in cancer-associated thrombosis, and elevated biomarkers of NET formation are associated with poor prognosis. OBJECTIVES: To investigate the association between NET formation and occult cancer in patients with VTE. METHODS: Blood biomarkers associated with NETs and neutrophil activation (nucleosomal citrullinated histone H3 [H3Cit-DNA], cell-free DNA, and neutrophil elastase) were quantified in patients with VTE. The primary outcome was cancer diagnosed during a one-year follow-up. RESULTS: This study included 460 patients with VTE, of which 221 (48%) had isolated deep vein thrombosis. Forty-three patients had active cancer at inclusion and were excluded from the primary analysis Cancer during follow-up was diagnosed in 29 of 417 (7.0%) patients. After adjustment for age and unprovoked VTE, the hazard ratio of cancer during follow-up per 500 ng/mL increase of H3Cit-DNA was 1.79 (95% CI, 1.03-3.10). Furthermore, patients with cancer-associated VTE (known active cancer or cancer diagnosed during follow-up) had higher levels of H3Cit-DNA than cancer-free patients with VTE after adjustment for age, hemoglobin, gender, chronic obstructive pulmonary disease, previous cancer, and start of anticoagulant treatment (odds ratio 2.06 per 500 ng/mL increase of H3Cit-DNA [95% CI, 1.35-3.13]). CONCLUSIONS: H3Cit-DNA is an independent predictor for occult cancer in patients with VTE and elevated in cancer-associated VTE, suggesting that H3Cit-DNA is potentially a useful diagnostic marker for cancer in patients with VTE and that elevated NET formation is a hallmark of cancer-associated VTE.

Inhaled ciclesonide in adults hospitalised with COVID-19: a randomised controlled open-label trial (HALT COVID-19).

OBJECTIVE: To assess the efficacy of inhaled ciclesonide in reducing the duration of oxygen therapy (an indicator of time to clinical improvement) among adults hospitalised with COVID-19. DESIGN: Multicentre, randomised, controlled, open-label trial. SETTING: 9 hospitals (3 academic hospitals and 6 non-academic hospitals) in Sweden between 1 June 2020 and 17 May 2021. PARTICIPANTS: Adults hospitalised with COVID-19 and receiving oxygen therapy. INTERVENTION: Inhaled ciclesonide 320 µg two times a day for 14 days versus standard care. MAIN OUTCOME MEASURES: Primary outcome was duration of oxygen therapy, an indicator of time to clinical improvement. Key secondary outcome was a composite of invasive mechanical ventilation/death. RESULTS: Data from 98 participants were analysed (48 receiving ciclesonide and 50 receiving standard care; median (IQR) age, 59.5 (49-67) years; 67 (68%) men). Median (IQR) duration of oxygen therapy was 5.5 (3-9) days in the ciclesonide group and 4 (2-7) days in the standard care group (HR for termination of oxygen therapy 0.73 (95% CI 0.47 to 1.11), with the upper 95% CI being compatible with a 10% relative reduction in oxygen therapy duration, corresponding to a <1 day absolute reduction in a post-hoc calculation). Three participants in each group died/received invasive mechanical ventilation (HR 0.90 (95% CI 0.15 to 5.32)). The trial was discontinued early due to slow enrolment. CONCLUSIONS: In patients hospitalised with COVID-19 receiving oxygen therapy, this trial ruled out, with 0.95 confidence, a treatment effect of ciclesonide corresponding to more than a 1 day reduction in duration of oxygen therapy. Ciclesonide is unlikely to improve this outcome meaningfully. TRIAL REGISTRATION NUMBER: NCT04381364.

Feasibility of monitoring the resolution of acute pulmonary embolism with non-contrast-enhanced magnetic resonance imaging at one day, one week, one, three, and six months.

BACKGROUND: Pulmonary embolism (PE) is a common cause of death with an incidence of approximately 1-2 cases per 1000 inhabitants in Europe and the United States. Treatment for PE is the administration of anticoagulants for at least three months. PURPOSE: To assess the feasibility of following the resolution rate of PE over time using repeated imaging with a non-contrast-enhanced magnetic resonance imaging (MRI) protocol. MATERIAL AND METHODS: Patients (n = 18) diagnosed with acute PE via computed tomography pulmonary angiography (CTPA) underwent non-contrast-enhanced MRI at two tertiary hospitals. The first MRI was performed within 36 h of CTPA, with follow-up at one week, one, three, and six months. The MRI sequence used was a non-contrast-enhanced standard two-dimensional steady-state free precession under free-breathing and without respiratory or cardiac gating. All MRI scans were then compared to the initial CTPA. The emboli were assessed visually for location and size, and clot burden was calculated using the Qanadli score. RESULTS: MRI revealed complete resolution in seven cases at one week, in five cases at one month, and in three cases at three months. The most significant resolution of emboli occurred within the first few weeks, with only 10% of the diagnosed emboli persisting at the one-month examination. CONCLUSION: The use of MRI imparts the ability to visualize PE without radiation and thus allows multiple examinations to be made, for example in studies investigating the resolution of PE or the evaluation of drug effect in clinical trials.

Prolonged electrocardiography registration does not lead to increased diagnosis of atrial fibrillation in pulmonary embolism patients, but sex affects generic health-related quality of life: Findings from a randomized clinical trial.

BACKGROUND: Pulmonary embolism (PE) is the third most common cause of cardiovascular death. Atrial fibrillation (AF) is the most common arrhythmia and is commonly detected in patients after embolic stroke. In this study, we set out to study if undiagnosed AF could be detected in patients with PE. In survivors of PE, persisting symptoms and exercise limitations are common. The disease burden of PE on quality of life (QoL) has received scarce attention. The primary aim was to study the prevalence of AF in patients with newly diagnosed PE. The secondary aim was to study QoL in PE patients. METHODS: Patients with newly diagnosed acute PE were randomized 1:1 to long-term electrocardiogram (ECG) screening for AF (handheld ECG or ECG patch) or standard-of-care. The study participants were asked to complete RAND-36 questionnaires upon inclusion. RESULTS: In total 89 PE patients (mean age 74.6 years) were included, and 40 out of these patients were randomized to AF screening. The study was terminated early due to futility when analysis 1 year after inclusion did not find any patients with newly detected AF.RAND-36 showed that QoL was affected in PE patients. Interestingly, sex differences were found; women had a significantly lower QoL in the dimensions of vitality (P = .006), general health (P = .039), and mental health (P = .041). CONCLUSION: Screening for AF in PE patients did not yield a significant proportion of new cases. QoL is more affected in female patients with PE, and increased awareness of this is suggested.

Comparing 'clinical hunch' against clinical decision support systems (PERC rule, wells score, revised Geneva score and YEARS criteria) in the diagnosis of acute pulmonary embolism.

BACKGROUND: Pulmonary embolism (PE) is a common and potentially life-threatening condition. Since it is considered a 'do not miss' diagnosis, PE tends to be over-investigated beyond the evidence-based clinical decision support systems (CDSS), which in turn subjects patients to unnecessary radiation and contrast agent exposure with no apparent benefits in terms of outcome. The purpose of this study was to evaluate the yield of 'clinical hunch' (gestalt) and four CDSS: the PERC Rule, Wells score, revised Geneva score, and Years criteria. METHODS: A review was conducted on the Electronic Medical Records (EMR) of 1566 patients from the Emergency Department at a tertiary teaching hospital who underwent CTPA from the 1st of January 2018 to the 31st of December 2019. The scores for the four CDSS were calculated retrospectively from the EMR data. We considered that a CTPA had been ordered on a clinical hunch when there was no mention of CDSS in the EMR, and no D-dimer test. A bypass of CDSS was confirmed when any step of the diagnostic algorithms was not followed. RESULTS: Of the total 1566 patients who underwent CTPA, 265 (17%) were positive for PE. The diagnosis yield from the five decision groups (clinical hunch and four CDSS) was as follows-clinical hunch, 15%; PERC rule, 18% (6% when bypassed); Wells score, 19% (11% when bypassed); revised Geneva score, 26% (13% when bypassed); and YEARS criteria, 18% (6% when bypassed). CONCLUSION: Clinicians should trust the evidence-based clinical decision support systems in line with the international guidelines to diagnose PE.

Development of an international standard set of outcome measures for patients with venous thromboembolism: an International Consortium for Health Outcomes Measurement consensus recommendation.

The International Consortium for Health Outcomes Measurement assembled an international working group of venous thromboembolism experts and patient representatives to develop a standardised minimum set of outcomes and outcome measurements for integration into clinical practice and potentially research to support clinical decision making and benchmarking of quality of care. 15 core outcomes important to patients and health-care professionals were selected and categorised into four domains: patient-reported outcomes, long term consequences of the disease, disease-specific complications, and treatment-related complications. The outcomes and outcome measures were designed to apply to all patients with venous thromboembolism aged 16 years or older. A measurement tool package was selected for inclusion in the core standard set, with a minimum number of items to be measured at predefined timepoints, which capture all core outcomes. Additional measures can be introduced to the user by a cascade opt-in system that allows for further assessment if required. This set of outcomes and measurement tools will facilitate the implementation of the use of patient-centred outcomes in daily practice.

Detection of upper extremity deep vein thrombosis by magnetic resonance non-contrast thrombus imaging.

BACKGROUND: Compression ultrasonography (CUS) is the first-line imaging test for diagnosing upper extremity deep vein thrombosis (UEDVT), but often yields inconclusive test results. Contrast venography is still considered the diagnostic standard but is an invasive technique. OBJECTIVES: We aimed to determine the diagnostic accuracy of magnetic resonance noncontrast thrombus imaging (MR-NCTI) for the diagnosis of UEDVT. METHODS: In this international multicenter diagnostic study, we prospectively included patients with clinically suspected UEDVT who were managed according to a diagnostic algorithm that included a clinical decision rule (CDR), D-dimer test, and diagnostic imaging. UEDVT was confirmed by CUS or (computed tomography [CT]) venography. UEDVT was excluded by (1) an unlikely CDR and normal D-dimer, (2) a normal serial CUS or (3) a normal (CT) venography. Within 48 h after the final diagnosis was established, patients underwent MR-NCTI. MR-NCTI images were assessed post hoc by two independent radiologists unaware of the presence or absence of UEDVT. The sensitivity, specificity, and interobserver agreement of MR-NCTI for UEDVT were determined. RESULTS: Magnetic resonance noncontrast thrombus imaging demonstrated UEDVT in 28 of 30 patients with UEDVT and was normal in all 30 patients where UEDVT was ruled out, yielding a sensitivity of 93% (95% CI 78-99) and specificity of 100% (95% CI 88-100). The interobserver agreement of MR-NCTI had a kappa value of 0.83 (95% CI 0.69-0.97). CONCLUSIONS: Magnetic resonance noncontrast thrombus imaging is an accurate and reproducible method for diagnosing UEDVT. Clinical outcome studies should determine whether MR-NCTI can replace venography as the second-line imaging test in case of inconclusive CUS.

Cost-effectiveness of magnetic resonance imaging for diagnosing recurrent ipsilateral deep vein thrombosis.

The diagnostic workup of recurrent ipsilateral deep vein thrombosis (DVT) using compression ultrasonography (CUS) can be complicated by persistent intravascular abnormalities after a previous DVT. We showed that magnetic resonance direct thrombus imaging (MRDTI) can exclude recurrent ipsilateral DVT. However, it is unknown whether the application of MRDTI in daily clinical practice is cost effective. The aim of this study was to evaluate the cost effectiveness of MRDTI-based diagnosis for suspected recurrent ipsilateral DVT during first year of treatment and follow-up in the Dutch health care setting. Patient-level data of the Theia study (NCT02262052) were analyzed in 10 diagnostic scenarios, including a clinical decision rule and D-dimer test and imaging with CUS and/or MRDTI. The total costs of diagnostic tests and treatment during 1-year follow-up, including costs of false-positive and false-negative diagnoses, were compared and related to the associated mortality. The 1-year health care costs with MRDTI (range, €1219-1296) were generally lower than strategies without MRDTI (range, €1278-1529). This was because of superior specificity, despite higher initial diagnostic costs. Diagnostic strategies including CUS alone and CUS followed by MRDTI in case of an inconclusive CUS were potential optimal cost-effective strategies, with estimated average costs of €1529 and €1263 per patient and predicted mortality of 1 per 737 patients and 1 per 609 patients, respectively. Our model shows that diagnostic strategies with MRDTI for suspected recurrent ipsilateral DVT have generally lower 1-year health care costs than strategies without MRDTI. Therefore, compared with CUS alone, applying MRDTI did not increase health care costs.

Changes in the plasma microvesicle proteome during the ovarian hyperstimulation phase of assisted reproductive technology.

The incidence of pulmonary and venous thromboembolism is increased during the first trimester of pregnancies after assisted reproductive technology (ART) compared to spontaneous conception. We previously found that haemostatic plasma variables changed but within normal limits during controlled ovarian hyperstimulation (COH) concomitant with a major increase in plasma microvesicles (MVs) and markers indicating cell activation. We now explored the proteome of these MVs. Thirty-one women undergoing ART were blood sampled at down-regulation (DR) of oestrogen and at high level stimulation (HLS) with its 10-100-fold increased oestrogen level. Samples were analysed by liquid chromatography and tandem mass spectrometry to identify and quantify the proteome. We identified 306 proteins in the MVs and 72 had changed significantly at HLS compared to DR and more than 20% of them were associated with haemostasis. Thus, proteins related to both haemostasis and complement activation altered in plasma MVs in parallel with MV activation during COH. This needs to be further explored in the clinical context.

Safety of using the combination of the Wells rule and D-dimer test for excluding acute recurrent ipsilateral deep vein thrombosis.

BACKGROUND: The diagnostic accuracy of clinical probability assessment and D-dimer testing for clinically suspected recurrent deep vein thrombosis (DVT) is largely unknown. AIM: To evaluate the safety of ruling out acute recurrent DVT based on an unlikely Wells score for DVT and a normal D-dimer test. METHODS: This was a predefined endpoint of the Theia study in which the diagnostic accuracy of magnetic resonance direct thrombus imaging in acute recurrent ipsilateral DVT was validated. The Wells rule and D-dimer test, performed as part of the study protocol, were not used for management decisions. The primary outcome of this analysis was the incidence of recurrent DVT at baseline or during 3-month follow-up for patients with an unlikely Wells score and a normal D-dimer test. RESULTS: Results of both Wells score and D-dimer tests were available in 231 patients without anticoagulant treatment. The recurrent DVT prevalence was 45% (103/231). Forty-nine patients had an unlikely Wells score and normal D-dimer test, of whom 3 (6.1%, 95% confidence interval [CI] 1.3%-18%) had recurrent DVT at baseline/follow-up, yielding a sensitivity of 97% (95% CI 92%-99%) and specificity of 36% (95% CI 28%-45%). Thus, if clinical probability scoring and D-dimer testing would have been applied, radiological imaging could have been omitted in 21% of patients with a diagnostic failure rate of 6.1%. CONCLUSION: By applying clinical probability scoring and D-dimer testing, radiological imaging could be spared in one fifth of patients with suspected recurrent ipsilateral DVT. However, the high failure rate does not support implementation of this strategy in daily practice.

Incidence of pulmonary and venous thromboembolism in pregnancies after in vitro fertilization with fresh respectively frozen-thawed embryo transfer: Nationwide cohort study.

BACKGROUND: The assisted reproductive technique in vitro fertilization (IVF) is associated with an increased risk of venous thromboembolism (VTE) and pulmonary embolism (PE) during the first trimester. OBJECTIVES: To compare the incidence of VTE and PE during the first trimester of IVF pregnancies using fresh or frozen-thawed embryo transfer to that during natural pregnancies. PATIENT/METHODS: Nationwide Swedish registry-based cohort study of women who gave birth (n = 902 891) at the age of 15-50 years to their first child from the 1st of January 1992 until the 31st of December 2012. Exposure groups were IVF with fresh respectively frozen-thawed embryo transfer. Incidences of VTE and PE were calculated, and time-varying hazard ratios estimated for all trimesters after fresh respectively frozen-thawed embryo transfer IVF and compared to natural conception. RESULTS AND CONCLUSION: Women giving birth after fresh embryo transfer IVF had a more than eightfold increased incidence of venous thromboembolism (hazard ratio [HR] 8.96, 95% CI 6.33 to 12.67) and pulmonary embolism during the first trimester, (HR 8.69, 95% CI 3.83 to 19.71) compared to women giving birth after natural conception. The incidence of VTE in women giving birth after frozen-thawed embryo transfer was not increased during the first trimester. To conclude, fresh embryo transfer IVF was associated with a significantly increased incidence of VTE and PE during the first trimester. These results suggest that frozen-thawed embryo transfer could be a preferred method of IVF with a minimised maternal risk.

Magnetic resonance imaging for diagnosis of recurrent ipsilateral deep vein thrombosis.

The diagnosis of recurrent ipsilateral deep vein thrombosis (DVT) is challenging, because persistent intravascular abnormalities after previous DVT often hinder a diagnosis by compression ultrasonography. Magnetic resonance direct thrombus imaging (MRDTI), a technique without intravenous contrast and with a 10-minute acquisition time, has been shown to accurately distinguish acute recurrent DVT from chronic thrombotic remains. We have evaluated the safety of MRDTI as the sole test for excluding recurrent ipsilateral DVT. The Theia Study was a prospective, international, multicenter, diagnostic management study involving patients with clinically suspected acute recurrent ipsilateral DVT. Treatment of the patients was managed according to the result of the MRDTI, performed within 24 hours of study inclusion. The primary outcome was the 3-month incidence of venous thromboembolism (VTE) after a MRDTI negative for DVT. The secondary outcome was the interobserver agreement on the MRDTI readings. An independent committee adjudicated all end points. Three hundred five patients were included. The baseline prevalence of recurrent DVT was 38%; superficial thrombophlebitis was diagnosed in 4.6%. The primary outcome occurred in 2 of 119 (1.7%; 95% confidence interval [CI], 0.20-5.9) patients with MRDTI negative for DVT and thrombophlebitis, who were not treated with any anticoagulant during follow-up; neither of these recurrences was fatal. The incidence of recurrent VTE in all patients with MRDTI negative for DVT was 1.1% (95% CI, 0.13%-3.8%). The agreement between initial local and post hoc central reading of the MRDTI images was excellent (κ statistic, 0.91). The incidence of VTE recurrence after negative MRDTI was low, and MRDTI proved to be a feasible and reproducible diagnostic test. This trial was registered at www.clinicaltrials.gov as #NCT02262052.

Diffusion-weighted imaging in acute pulmonary embolism: a feasibility study.

BACKGROUND: Magnetic resonance imaging (MRI) can be an alternative method to computed tomography angiography (CTA) for pulmonary embolism. PURPOSE: To evaluate the feasibility of diffusion-weighted imaging (DWI) detecting acute pulmonary embolism (PE) in free-breathing humans. MATERIAL AND METHODS: Twenty patients with PE verified by CTA and 20 controls were investigated with MRI (1.5 Aera, Siemens Healthcare). All sequences were performed in the transversal plane using free-breathing without gating. The protocol consisted of a two-dimensional steady-state free precession (SSFP) and a single-shot DWI echo-planar imaging sequence with a voxel resolution of 2 × 2 × 5 mm. Three b values were used: 50, 400, and 800 s/mm2. Images were analyzed in two orders: an open source analysis (OSA); and a blinded only DWI analysis (BDA) simulating clinical work. RESULTS: OSA of corresponding images showed 370 findings on CTA (i.e. one elongated emboli could be represented in multiple images). SSFP identified 237 of those (64%). DWI with b values of 50, 400, and 800 identified 327 (88%), 245 (66%), and 138 (37%), respectively. In BDA we found 160 true emboli (according to CTA) on b50, 78 on b400, and 54 on b800. Fifty-two of these findings at the subsegmental level could be correlated to PE on CTA but were not visible on SSFP. CONCLUSIONS: DWI has a high sensitivity for detecting PE but suffers from poor specificity. It could potentially be used as an eye catcher, i.e. where to look for PE in other MRI sequences.

How to train radiology residents to diagnose pulmonary embolism using a dedicated MRI protocol.

BACKGROUND: In recent years, magnetic resonance imaging (MRI) has been suggested as an alternative to computed tomography angiography (CTA) to diagnose pulmonary embolism (PE). In previous studies, only senior radiologists have been evaluated as reviewers. PURPOSE: To investigate if radiology residents can be trained to review MRI regarding PE and to determine the learning curve effects. MATERIAL AND METHODS: Four residents independently went through a training program consisting of 70 participants that had undergone steady-state free precession MRI. The individuals were randomized into ten training sessions. For each exam, the review time and presence or absence of embolus was recorded. After completing each session, the residents received feedback on diagnostic accuracy compared to a consensus reading by two specialists. The residents were also presented with the corresponding CTA. RESULTS: The review time was nearly halved (P = 0.0002) during the training program. Comparing the first three sessions with the last three sessions for all residents, the review time decreased from 5:22 min to 2:51 min. The inter-reader agreement improved for all residents during the training program reaching a clinically acceptable level after seven sessions. CONCLUSION: Our study suggests that radiology residents can be trained to independently review MRI investigations regarding PE within a short training program. Similar training programs could be more extensively used as effective teaching method for residents.

Detection of pulmonary embolism using repeated MRI acquisitions without respiratory gating: a preliminary study.

Background Pulmonary embolism (PE) is a severe medical condition with non-specific clinical findings. Computed tomography angiography (CTA) using iodinated contrast agents is the golden standard for diagnosis, but many patients have contraindications for CTA. Purpose To investigate the diagnostic accuracy of repeated acquisitions of magnetic resonance imaging (MRI), without respiratory gating or breath holding, in diagnosing PE using CTA as the reference standard. Material and Methods Thirty-three patients with clinically suspected PE underwent MRI within 48 h after diagnostic CTA. A control group of 37 healthy participants underwent MRI and was matched with an equal number of negative CTA exams. The MRI protocol was based on free-breathing steady-state free precession producing 4.5 mm slices in axial, sagittal, and coronal planes. Instead of respiratory or cardiac gating five repetitive slices were obtained in each anatomical position to compensate for movement and artifacts. Clinical assessment including d-dimer and Well's score was performed prior to imaging. One radiologist reviewed the CTA exams and two radiologists reviewed the MRI scans. Results All 70 MRI exams were of diagnostic quality and the total acquisition time for each MRI scan was 9 min 34 s. On CTA, 29 patients were diagnosed with PE and the MRI readers detected 26 and 27 of those, respectively. Specificity was 100% for both readers. Sensitivity was 90% and 93%, respectively. Inter-reader agreement using Cohen's kappa was 0.97. Conclusion Our unenhanced MRI protocol shows a high sensitivity and specificity for PE, but further studies are required before considering it as a safe diagnostic test.

Microparticles reveal cell activation during IVF - a possible early marker of a prothrombotic state during the first trimester.

Cell-derived microparticles (MPs) are known to be elevated in a number of diseases related to arterial and venous thromboembolism (VTE), such as acute myocardial infarction, VTE (deep-vein thrombosis and pulmonary embolism) and peripheral arterial disease. IVF-associated pregnancies have previously been shown to be associated with an increased incidence of VTE, mechanisms behind being unknown and sparsely studied. Our objective was to assess cell activation during IVF through analysis of MP levels and phenotype following ovarian stimulation. Thirty-one women undergoing IVF were included and blood samples were collected at down regulation of oestrogen and at high level stimulation with 10- to 100-fold increased endogenous oestrogen levels. MPs were analysed by flow cytometry and phenotyped according to size and protein expression. We found that overall phosphatidylserine positive platelet-, endothelial- and monocyte-derived MPs significantly increased following ovarian stimulation with increased levels of platelet activation markers CD40 ligand and P-selectin. Furthermore, there was an increase in endothelial-derived MPs exposing activation marker E-selectin and monocyte-derived MPs, while neutrophil-derived MPs decreased slightly. In conclusion we found a major increase in MPs and markers indicating cell activation in parallel with the profound oestrogen boost during IVF. To assess whether these changes in MPs are associated with thromboembolic events requires extended longitudinal studies.